JP2006276346A - Original plate for lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original plate for a lithographic printing plate which is superior in any of printing durability, ink-blur staining resistance, erasure staining resistance, and self-staining resistance. <P>SOLUTION: The original plate for the lithographic printing plate has an aluminum substrate which is treated with a solution of pH11.5 to 13.0 including an alkali metal silicate solution to have a 3.0 to 15.0 mg/m<SP>2</SP>surface Si amount, an intermediate layer formed on the aluminum substrate by using a constituent component having an acid radical and a constituent component having an onium radical, and an image forming layer formed on the intermediate layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate precursor using an aluminum plate as a support.

  In general, a lithographic printing plate precursor is subjected to a roughening treatment such as a mechanical roughening treatment or an electrochemical roughening treatment on the surface of an aluminum plate, and further anodized to form an anodized film. After the formation, the photosensitive layer is applied and dried to form a photosensitive layer (hereinafter also referred to as an image recording layer). The lithographic printing plate precursor is exposed to an image and then developed with a developer. The exposed portion is removed from the positive type lithographic printing plate precursor, and the non-exposed portion is removed from the negative type lithographic printing plate precursor. Printed version.

  The lithographic printing plate obtained in this manner is then attached to the plate cylinder of a printing press, and ink and fountain solution are supplied to the surface and used for printing. The ink-affinity becomes an image part, and the part from which the photosensitive layer is removed becomes hydrophilic and becomes a non-image part, and is printed on paper.

  The surface of the support for a lithographic printing plate has excellent hydrophilicity because it is used so as to carry a non-image part, and has excellent adhesion with an image recording layer formed thereon, etc. Therefore, various contradictory performances are required. If the hydrophilicity of the surface of the lithographic printing plate support is too low, ink will adhere to the non-image area during printing, and the blanket cylinder will be soiled, and so-called background soiling will occur. That is, the stain resistance is deteriorated. On the other hand, if the adhesion between the lithographic printing plate support and the image recording layer is too low, the image recording layer is easily peeled off and the durability (printing durability) is deteriorated when the number of printed sheets is large.

  Therefore, the lithographic printing plate support is subjected to an alkali metal silicate treatment (also referred to as a silicate treatment or a hydrophilization treatment) in order to improve the hydrophilicity of the surface before forming the image recording layer. In order to improve the adhesion to the image recording layer, an intermediate layer is further formed after the hydrophilic treatment.

  For example, in Patent Document 1, an anodized aluminum plate is an aqueous solution of an alkali metal silicate containing a hydroxide, having a pH of 12.4 to 13.0 at 25 ° C. and a specific gravity of 1. A method for producing a support for a lithographic printing plate is described, wherein the treatment is performed with an aqueous solution having a conductivity of 35 to 180 [mS / cm] at 70 ° C.

  Patent Document 2 discloses photosensitivity in which a positive photosensitive layer is provided on a hydrophilized aluminum support on which a component having an acid group and a polymer compound having an onium group are provided. A lithographic printing plate is described.

Patent Document 3 discloses a lithographic printing plate precursor in which a heat-sensitive layer whose solubility in an alkaline aqueous solution is changed by heating on an aluminum support, and the amount of Si atoms attached to the surface of the aluminum support is 5. A lithographic printing plate precursor of ˜20 mg / cm ² is described.

Patent Document 4 discloses a lithographic printing plate support obtained by subjecting an aluminum plate to an electrochemical surface roughening treatment using an aqueous solution containing at least hydrochloric acid, an anodizing treatment, and an alkali metal silicate treatment. In addition, a lithographic printing plate precursor having an image recording layer capable of forming an image by heat, wherein the lithographic printing plate precursor has large pits having an average opening diameter of 2 to 10 μm and an average opening diameter of 0.05 to 0. For the planographic printing plate, having a grained shape with a structure in which small pits of .8 μm are superposed on the surface, and the ratio of the depth to the opening diameter of the small pits is 0.2 to 0.6 on average. For the support, an actual area S _x ⁵⁰ obtained by an approximate three-point method from three-dimensional data obtained by measuring 512 × 512 points of 50 μm □ of the surface using an atomic force microscope, and a geometric measurement area S ₀ from ^50., the following equation (20) Ri surface area ratio ΔS obtained is 20 to 40%, Si atom adhesion quantity of the surface of the lithographic printing plate support has been described for the lithographic printing plate precursor is 1.0~15.0mg / m ² .
ΔS ⁵⁰ = (S _x ⁵⁰ −S ₀ ⁵⁰ ) / S ₀ ⁵⁰ × 100 (%) (20)

Japanese Patent Laid-Open No. 2-185493 Japanese Patent Laid-Open No. 10-282645 JP 2004-219661 A Japanese Patent Laid-Open No. 2004-249693

By the way, in the shadow portion of the printed matter, the area ratio of the halftone dots is high (70 to 90%), and in the area corresponding to that of the planographic printing plate, the area of the image portion (image recording layer) is large and the non-image portion (support) The area of the exposed part of the body is relatively small.
In such a case, when printing, especially when the supply amount of dampening water is reduced, the inks placed on adjacent image parts come into contact with each other (that is, entangled), and the non-image part between them comes into contact. A phenomenon that ink adheres and a non-image portion of a printed material is crushed (that is, soiled) easily occurs. Such a phenomenon is called “entangled dirt”.
In recent years, the demand for FM screen printing has been increasing for the purpose of high-definition printing, but FM screens that adjust the density by the density of halftone dots are compared with AM screens that adjust the density by the size of the halftone dots. Since the distance between adjacent halftone dots in the shadow portion is small, the above-described entanglement contamination is likely to occur.

Further, in a lithographic printing plate precursor, there is a case where an image recording layer that should be removed after development may remain due to adhesion of dust or the like. In such a case, it is used for the image recording layer. An image to be originally removed is removed using an erasing solution containing a solvent such as a coating solvent and an acid such as phosphoric acid.
At this time, if an image recording layer, an intermediate layer, or the like remains in the area where the erasing liquid is used, ink adheres during printing, and the non-image area is stained. Such a phenomenon is called “erasing dirt”.

In addition, when printing is performed, printing may be temporarily stopped. In this case, the planographic printing plate is left unattended, and the non-image portion is stained due to the influence of contamination in the atmosphere. For this reason, when printing is paused and resumed, the printed matter becomes dirty. This stain is referred to as “left stain”. If the unclean stain occurs, it becomes necessary to print several sheets until normal printing is performed, and there is a disadvantage that printing paper is wasted.
Therefore, lithographic printing plates are required to have excellent anti-entanglement stain resistance, erasure stain resistance and neglected stain resistance when FM screens are used for halftone dots in addition to printing durability. .

  However, the proposal regarding the hydrophilic treatment and the formation of the intermediate layer described above is not intended to improve the balance between water and ink when an FM screen is used for halftone dots. When a screen is used, it is not possible to sufficiently achieve a lithographic printing plate precursor having excellent printing resistance, entanglement stain resistance, erasure stain resistance, and neglectable stain resistance.

  Accordingly, the present invention provides a lithographic printing plate precursor having excellent printing resistance, entanglement stain resistance, erasure stain resistance, neglectable stain resistance, and erasure stain resistance even when an FM screen is employed for the halftone dots. The purpose is to provide.

  As a result of intensive studies to achieve the above object, the present inventor uses an aluminum plate that has been subjected to a silicate treatment in which the pH of the alkali metal silicate aqueous solution to be used is controlled and the amount of Si adhering to the surface is within a desired range. In addition, by including a specific polymer compound in the intermediate layer, even when an FM screen is used for the halftone dots, printing durability, entanglement stain resistance, erasure stain resistance, neglected stain resistance, The present inventors have found that a lithographic printing plate precursor having excellent erasability due to erasure can be obtained, thereby completing the present invention.

  That is, the present invention provides the following (I) to (IV).

(I) Aluminum having a surface Si amount of 3.0 to 15.0 mg / m ² obtained by treatment with an aqueous solution containing alkali metal silicate and having a pH of 11.5 to 13.0. A plate, an intermediate layer formed using a polymer material including a component having an acid group and a component having an onium group on the aluminum plate, and an image recording layer formed on the intermediate layer Lithographic printing plate precursor.

(II) The lithographic printing plate precursor as described in (I) above, wherein the aluminum plate has a surface area ratio ΔS of 10 to 50% and a steepness a45 of 5 to 40%.
However, the surface area ratio ΔS is obtained by measuring the actual area S _x obtained by the approximate three-point method from the three-dimensional data obtained by measuring 512 × 512 points of the surface 50 μm □ using an atomic force microscope, and geometric measurement. The area S ₀ is a value obtained by the following formula (1), and the steepness a45 is an area of a portion having an inclination of 45 ° or more with respect to the actual area S _x (an inclination of 45 ° or more). Rate.
ΔS = (S _x −S ₀ ) / S ₀ × 100 (%) (1)

  (III) The intermediate layer includes a polymer compound containing 60 to 80 mol% of the component having the acid group and 20 to 40 mol% of the component having the onium group. The lithographic printing plate precursor as described in (II).

  (IV) The image recording layer includes an alkali-soluble polymer compound, a photothermal conversion substance, (a) a monomer represented by the following formula (2), and (b) an aliphatic group having 7 or more carbon atoms having a bridge-like bond. The lithographic printing plate precursor as described in any one of (I) to (III) above, comprising a monomer having a group and (c) a fluorine-based polymer compound containing a monomer having an acid group as a copolymerization component.

In the formula (2), Rf is a substituent containing a fluoroalkyl group or a perfluoroalkyl group having 9 or more fluorine atoms, n is 1 or 2, and R ¹ is hydrogen or a methyl group. .

As will be described below, according to the present invention, even when an FM screen is used as a halftone dot, printing durability is good and any of entanglement stain resistance, erasure stain resistance, and neglected stain resistance is achieved. It is possible to obtain an excellent lithographic printing plate precursor.
That is, even when FM screen printing is performed, it is possible to perform image printing in which contamination of the non-image portion is suppressed. In addition, even when the image area is removed with an erasing liquid after development, the image recording layer and the intermediate layer are not left in the area where the erasing liquid is used, and an image in which the stain on the non-image area is suppressed is printed. It becomes possible. Further, it is possible to reduce waste of printing paper caused by temporarily stopping printing.

Hereinafter, the present invention will be described in detail.
[Support for lithographic printing plate]
<Aluminum plate (rolled aluminum)>
In order to obtain the lithographic printing plate precursor according to the present invention, a known aluminum plate can be used. The aluminum plate used in the present invention is a metal mainly composed of dimensionally stable aluminum, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and a trace amount of foreign elements can also be used.

  In the present specification, various substrates made of the above-described aluminum or aluminum alloy are generically used as an aluminum plate. The foreign elements that may be contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium, and the content of the foreign elements in the alloy is 10% by mass or less. It is.

  Thus, the composition of the aluminum plate used in the present invention is not specified. For example, a conventionally known material described in the fourth edition of the Aluminum Handbook (1990, published by the Light Metal Association), for example, JIS Al-Mn aluminum plates such as A1050, JIS A1100, JIS A1070, JIS A3004 containing Mn, and internationally registered alloy 3103A can be appropriately used. For the purpose of increasing the tensile strength, an Al—Mg alloy or an Al—Mn—Mg alloy (JIS A3005) in which 0.1% by mass or more of magnesium is added to these aluminum alloys can also be used. Furthermore, an Al—Zr alloy or an Al—Si alloy containing Zr or Si can also be used. Furthermore, an Al—Mg—Si based alloy can also be used.

  Regarding the JIS 1050 material, the techniques proposed by the applicant of the present application are disclosed in Japanese Patent Application Laid-Open Nos. 59-153861, 61-51395, 62-146694, 60-215725, and 60-215725. JP 60-215726, JP 60-215727, JP 60-216728, JP 61-272367, JP 58-11759, JP 58-42493, JP 58- 221254, JP-A-62-148295, JP-A-4-254545, JP-A-4-165541, JP-B-3-68939, JP-A-3-234594, JP-B-1-47545, and JP-A-62. It is described in each publication of -140894. In addition, techniques described in Japanese Patent Publication No. 1-35910 and Japanese Patent Publication No. 55-28874 are also known.

  Regarding the JIS1070 material, the techniques proposed by the applicant of the present application are disclosed in JP-A-7-81264, JP-A-7-305133, JP-A-8-49034, JP-A-8-73974, JP-A-8-108659 and It is described in JP-A-8-92679.

  Regarding Al-Mg alloys, the techniques proposed by the applicant of the present application are disclosed in Japanese Patent Publication Nos. Sho 62-5080, Sho 63-60823, Shoko 3-61753, JP Sho 60-20396, JP-A-60-203497, JP-B-3-11635, JP-A-61-274993, JP-A-62-23794, JP-A-63-47347, JP-A-63-47348, JP-A-63-47349. JP-A 64-1293, JP-A 63-135294, JP-A 63-87288, JP-B 4-73392, JP-B 7-100844, JP-A 62-149856, JP-B JP-A-4-73394, JP-A-62-181191, JP-B-5-76530, JP-A-63-30294, and JP-B-6-37116. Also described in JP-A-2-215599, JP-A-61-201747, and the like.

  With regard to Al—Mn alloys, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 60-230951, 1-306288, and 2-293189. In addition, JP-B-54-42284, JP-B-4-19290, JP-B-4-19291, JP-B-4-19292, JP-A-61-35995, JP-A-64-51992, JP-A-4-19592, No. 226394, US Pat. No. 5,009,722, US Pat. No. 5,028,276 and the like.

  With regard to the Al—Mn—Mg alloy, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 62-86143 and 3-2222796. JP-B 63-60824, JP-A 60-63346, JP-A 60-63347, JP-A-1-293350, European Patent No. 223,737, US Pat. No. 4,818, No. 300, British Patent No. 1,222,777, etc.

  Regarding the Al—Zr alloy, the technique proposed by the applicant of the present application is described in Japanese Patent Publication No. 63-15978 and Japanese Patent Application Laid-Open No. 61-51395. Also described in JP-A-63-143234 and JP-A-63-143235.

  The Al—Mg—Si alloy is described in British Patent 1,421,710.

  In order to use an aluminum alloy as a plate material, for example, the following method can be employed. First, a molten aluminum alloy adjusted to a predetermined alloy component content is subjected to a cleaning process and cast according to a conventional method. In the cleaning process, in order to remove unnecessary gas such as hydrogen in the molten metal, flux treatment, degassing process using argon gas, chlorine gas, etc., so-called rigid media filter such as ceramic tube filter, ceramic foam filter, A filtering process using a filter that uses alumina flakes, alumina balls or the like as a filter medium, a glass cloth filter, or a combination of a degassing process and a filtering process is performed.

  These cleaning treatments are preferably performed in order to prevent defects caused by foreign matters such as non-metallic inclusions and oxides in the molten metal and defects caused by gas dissolved in the molten metal. Regarding filtering of the molten metal, JP-A-6-57432, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, JP-A-5-311261, JP-A-5-311261 6-136466 and the like. Further, the degassing of the molten metal is described in JP-A-5-51659, Japanese Utility Model Laid-Open No. 5-49148, and the like. The applicant of the present application has also proposed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017.

Next, casting is performed using the molten metal that has been subjected to the cleaning treatment as described above. As for the casting method, there are a method using a solid mold typified by a DC casting method and a method using a driving mold typified by a continuous casting method.
In DC casting, solidification occurs at a cooling rate of 0.5 to 30 ° C./second. If it is less than 0.5 ° C./second, a large number of coarse intermetallic compounds may be formed. When DC casting is performed, an ingot having a thickness of 300 to 800 mm can be manufactured. The ingot is chamfered as necessary according to a conventional method, and usually 1 to 30 mm, preferably 1 to 10 mm, of the surface layer is cut. Before and after that, soaking treatment is performed as necessary. When performing a soaking treatment, heat treatment is performed at 450 to 620 ° C. for 1 to 48 hours so that the intermetallic compound does not become coarse. If the heat treatment is shorter than 1 hour, the effect of soaking may be insufficient.

  Then, hot rolling and cold rolling are performed to obtain a rolled aluminum plate. An appropriate starting temperature for hot rolling is 350 to 500 ° C. An intermediate annealing treatment may be performed before or after hot rolling or in the middle thereof. The conditions for the intermediate annealing treatment are heating at 280 to 600 ° C. for 2 to 20 hours, preferably 350 to 500 ° C. for 2 to 10 hours using a batch annealing furnace, or 400 to 600 ° C. using a continuous annealing furnace. Heating is performed for 6 minutes or less, preferably 450 to 550 ° C. for 2 minutes or less. The crystal structure can be made finer by heating at a heating rate of 10 to 200 ° C./second using a continuous annealing furnace.

  The flatness of the aluminum plate finished to a predetermined thickness, for example, 0.1 to 0.5 mm by the above steps may be further improved by a correction device such as a roller leveler or a tension leveler. The flatness may be improved after the aluminum plate is cut into a sheet shape, but in order to improve productivity, it is preferably performed in a continuous coil state. Further, a slitter line may be used for processing into a predetermined plate width. Moreover, in order to prevent generation | occurrence | production of the damage | wound by friction between aluminum plates, you may provide a thin oil film on the surface of an aluminum plate. As the oil film, a volatile or non-volatile film is appropriately used as necessary.

  On the other hand, as the continuous casting method, a twin roll method (hunter method), a method using a cooling roll typified by the 3C method, a double belt method (Hazley method), a cooling belt or a cooling block typified by Al-Swiss Caster II type The method using is industrially performed. When the continuous casting method is used, it solidifies at a cooling rate of 100 to 1000 ° C./second. Since the continuous casting method generally has a higher cooling rate than the DC casting method, it has a feature that the solid solubility of the alloy component in the aluminum matrix can be increased. Regarding the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-3-79798, JP-A-5-201166, JP-A-5-156414, JP-A-6-262203, and JP-A-6-122949. JP-A-6-210406 and JP-A-6-26308.

  When continuous casting is performed, for example, if a method using a cooling roll such as a Hunter method is used, a cast plate having a thickness of 1 to 10 mm can be directly cast continuously, and the hot rolling step is omitted. The advantage of being able to In addition, when a method using a cooling belt such as the Husley method is used, a cast plate having a thickness of 10 to 50 mm can be cast. Generally, a hot rolling roll is arranged immediately after casting and continuously rolled. Thus, a continuous cast and rolled plate having a thickness of 1 to 10 mm is obtained.

  These continuous cast and rolled plates are subjected to processes such as cold rolling, intermediate annealing, improvement of flatness, slits, and the like in the same manner as described for DC casting. Finished to a thickness of 5 mm. Regarding the intermediate annealing condition and the cold rolling condition when using the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-6-220593, JP-A-6-210308, JP-A-7-54111, It is described in JP-A-8-92709.

Various characteristics described below are desired for the aluminum plate thus manufactured.
As for the strength of the aluminum plate, it is preferable that the 0.2% proof stress is 140 MPa or more in order to obtain the stiffness required for a lithographic printing plate support. Further, in order to obtain a certain level of waist strength even when performing a burning treatment, the 0.2% yield strength after heat treatment at 270 ° C. for 3 to 10 minutes is preferably 80 MPa or more, and 100 MPa or more. It is more preferable that In particular, when the waist strength is required for an aluminum plate, an aluminum material added with Mg or Mn can be used, but if the waist is strengthened, the ease of fitting to the plate cylinder of a printing press becomes inferior. Depending on the application, the material and the amount of trace components added are appropriately selected. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 7-126820 and 62-140894.

  The crystal structure of the aluminum plate may cause poor surface quality when the surface of the aluminum plate is subjected to chemical or electrochemical surface roughening. It is preferably not too coarse. The crystal structure on the surface of the aluminum plate preferably has a width of 200 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, and the length of the crystal structure is 5000 μm or less. Is preferably 1000 μm or less, and more preferably 500 μm or less. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 6-218495, 7-39906, and 7-124609.

  The alloy component distribution of the aluminum plate, when chemical surface roughening treatment or electrochemical surface roughening treatment is performed, poor surface quality occurs due to non-uniform distribution of the alloy component on the surface of the aluminum plate. Therefore, it is preferable that the surface is not very uneven. With regard to these, the techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 6-48058, 5-301478, and 7-132689.

  In the intermetallic compound of the aluminum plate, the size and density of the intermetallic compound may affect the chemical roughening treatment or the electrochemical roughening treatment. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 7-138687 and 4-254545.

  In the present invention, an aluminum plate as shown above can be used with unevenness by lamination rolling, transfer, or the like in the final rolling step.

The aluminum plate used in the present invention is a continuous belt-like sheet material or plate material. That is, it may be an aluminum web, or a sheet-like sheet cut to a size corresponding to a planographic printing plate precursor shipped as a product.
Since scratches on the surface of the aluminum plate may become defects when processed into a lithographic printing plate support, it is possible to generate scratches at the stage prior to the surface treatment process for making a lithographic printing plate support It is necessary to suppress as much as possible. For that purpose, it is preferable that the package has a stable form and is hardly damaged during transportation.
In the case of an aluminum web, for example, the packaging of aluminum is, for example, laying a hardboard and felt on an iron pallet, applying cardboard donut plates to both ends of the product, wrapping the whole with a polytube, and inserting a wooden donut into the inner diameter of the coil Then, a felt is applied to the outer periphery of the coil, the band iron is used to squeeze it, and the display is performed on the outer periphery. Moreover, a polyethylene film can be used as the packaging material, and needle felt and hard board can be used as the cushioning material. There are various other forms, but the present invention is not limited to this method as long as it is stable and can be transported without being damaged.

  The thickness of the aluminum plate used in the present invention is about 0.1 to 0.6 mm, preferably 0.15 to 0.4 mm, and more preferably 0.2 to 0.3 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, the user's desires, and the like.

<Surface treatment>
The support for a lithographic printing plate used in the lithographic printing plate precursor according to the present invention is not particularly limited as long as it is subjected to an alkali metal silicate treatment. However, the aluminum plate is roughened, anodized, and It is preferably obtained by applying an alkali metal silicate treatment.

In the following, as a representative method for forming a suitable surface grain shape,
A method of sequentially performing mechanical surface roughening treatment, alkali etching treatment, desmutting treatment with an acid and electrochemical surface roughening treatment using an electrolytic solution on an aluminum plate,
A method of performing mechanical surface roughening treatment, alkaline etching treatment, desmutting treatment with acid and electrochemical surface roughening treatment using different electrolytes a plurality of times on an aluminum plate,
A method of sequentially performing an alkali etching treatment, an acid desmutting treatment on an aluminum plate, and an electrochemical surface roughening treatment using an electrolytic solution,
Examples include a method of subjecting an aluminum plate to alkali etching treatment, desmutting treatment with an acid, and electrochemical surface roughening treatment using different electrolytic solutions a plurality of times, but the present invention is not limited thereto. In these methods, after the electrochemical roughening treatment, an alkali etching treatment and an acid desmutting treatment may be further performed.

As a more preferable method,
Aluminum plate with mechanical surface roughening treatment, alkali etching treatment, desmutting treatment with acid, electrochemical surface roughening treatment using electrolytic solution containing nitric acid, alkaline etching treatment, desmutting treatment with acid, electrolytic solution containing hydrochloric acid The method of performing the electrochemical roughening process used, the alkali etching process, and the desmut process by an acid in order is mentioned.
Hereinafter, each step of the surface treatment will be described in detail.

<Mechanical roughening>
In the surface treatment, it is preferable to perform a mechanical surface roughening treatment.
Examples of the mechanical surface roughening treatment include, for example, a wire brush grain method in which the aluminum surface is scratched with a metal wire, a ball grain method in which the aluminum surface is grained with a polishing ball and an abrasive, JP-A-6-135175, and Japanese Patent Publication A brush grain method in which the surface is grained with a nylon brush and an abrasive described in Japanese Patent No. 50-40047 can be used.
A transfer method in which the uneven surface is pressed against the aluminum plate can also be used. That is, in addition to the methods described in JP-A-55-74898, JP-A-60-36195, and JP-A-60-20396, transfer is performed several times. The method described in JP-A-6-24168 and JP-A-6-24168 characterized in that the surface is elastic is also applicable.

In addition, by using electric discharge machining, shot blasting, laser, plasma etching, etc., a method of repeatedly transferring using a transfer roll etched with fine irregularities, and an uneven surface coated with fine particles on an aluminum plate It is also possible to use a method in which an uneven pattern corresponding to the average diameter of the fine particles is repeatedly transferred to the aluminum plate a plurality of times by contacting the surface and applying a pressure a plurality of times from above. As a method for imparting fine irregularities to the transfer roll, known methods described in JP-A-3-8635, JP-A-3-66404, JP-A-63-65017, etc. may be used. it can. Further, a fine groove may be cut in two directions using a die, a cutting tool, a laser, or the like on the roll surface, and a square unevenness may be formed on the surface. The roll surface may be subjected to a known etching process or the like so that the formed square irregularities are rounded.
Further, in order to increase the surface hardness, quenching, hard chrome plating, or the like may be performed.
In addition, as the mechanical surface roughening treatment, methods described in JP-A Nos. 61-162351 and 63-104889 can be used.
In the present invention, the above-described methods can be used in combination in consideration of productivity and the like. These mechanical surface roughening treatments are preferably performed before the electrochemical surface roughening treatment.

Hereinafter, the brush grain method used suitably as a mechanical roughening process is demonstrated.
The brush grain method generally uses a roller-shaped brush in which a large number of brush hairs such as synthetic resin hair made of synthetic resin such as nylon (trade name), propylene, and vinyl chloride resin are implanted on the surface of a cylindrical body. This is carried out by rubbing one or both of the surfaces of the aluminum plate while spraying a slurry liquid containing an abrasive on a rotating roller brush. Instead of the roller brush and the slurry liquid, a polishing roller which is a roller having a polishing layer on the surface can be used.
When a roller brush is used, the flexural modulus is preferably 10,000 to 40,000 kg / cm ² , more preferably 15,000 to 35,000 kg / cm ² , and the bristle strength is preferably Brush hair of 500 gf or less, more preferably 400 gf or less is used. The diameter of the brush bristles is generally 0.2 to 0.9 mm. The length of the brush bristles can be appropriately determined according to the outer diameter of the roller brush and the diameter of the body, but is generally 10 to 100 mm.

A well-known thing can be used for an abrasive | polishing agent. For example, abrasives such as pumicestone, silica sand, aluminum hydroxide, alumina powder, silicon carbide, silicon nitride, volcanic ash, carborundum, and gold sand; a mixture thereof can be used. Of these, pumiston and silica sand are preferable. In particular, silica sand is preferable in terms of excellent surface roughening efficiency because it is harder and less likely to break than Pamiston.
The average particle diameter of the abrasive is preferably 3 to 50 μm, and more preferably 6 to 45 μm in terms of excellent surface roughening efficiency and a narrow graining pitch.
For example, the abrasive is suspended in water and used as a slurry. In addition to the abrasive, the slurry liquid may contain a thickener, a dispersant (for example, a surfactant), a preservative, and the like. The specific gravity of the slurry liquid is preferably 0.5-2.

  As an apparatus suitable for the mechanical surface roughening treatment, for example, an apparatus described in Japanese Patent Publication No. 50-40047 can be given.

<Electrochemical roughening treatment>
In the electrochemical surface roughening treatment, an electrolytic solution used for the electrochemical surface roughening treatment using a normal alternating current can be used. Among these, a desired uneven structure can be formed on the surface by using an electrolytic solution mainly composed of hydrochloric acid or nitric acid.
As the electrochemical surface roughening treatment in the present invention, it is preferable to perform the first and second electrolytic treatments with an alternating waveform current in an acidic solution before and after the cathodic electrolytic treatment. By cathodic electrolysis, hydrogen gas is generated on the surface of the aluminum plate and smut is generated to make the surface state uniform, and uniform electrochemical roughening is possible during subsequent electrolysis with alternating waveform current It becomes.
This electrochemical surface roughening treatment can be performed according to, for example, an electrochemical grain method (electrolytic grain method) described in Japanese Patent Publication No. 48-28123 and British Patent No. 896,563. This electrolytic grain method uses a sinusoidal alternating current, but it may be performed using a special waveform as described in JP-A-52-58602. Further, the waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A-60-190392, JP-A-58-120531, JP-A-63-176187, JP-A-1-5889, JP-A-1-280590, JP-A-1-118489, JP-A-1-148592, and JP-A-1-17896. JP-A-1-188315, JP-A-1-1549797, JP-A-2-235794, JP-A-3-260100, JP-A-3-253600, JP-A-4-72079, JP-A-4-72098, The methods described in JP-A-3-267400 and JP-A-1-141094 can also be applied. In addition to the above, it is also possible to perform electrolysis using an alternating current having a special frequency that has been proposed as a method of manufacturing an electrolytic capacitor. For example, it is described in US Pat. Nos. 4,276,129 and 4,676,879.

Various electrolyzers and power sources have been proposed. U.S. Pat. No. 4,023,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP-A-53. -32821, JP-A 53-32822, JP-A 53-32823, JP-A 55-122896, JP-A 55-13284, JP-A 62-127500, JP-A-1-52100 JP-A-1-52098, JP-A-60-67700, JP-A-1-230800, JP-A-3-257199 and the like can be used.
Also, JP-A-52-58602, JP-A-52-152302, JP-A-53-12738, JP-A-53-12739, JP-A-53-32821, JP-A-53-32822, JP 53-32833, JP 53-32824, JP 53-32825, JP 54-85802, JP 55-122896, JP 55-13284, JP 48-28123, JP-B-51-7081, JP-A-52-13338, JP-A-52-133840, JP-A-52-133844, JP-A-52-133845, JP-A-53- Nos. 149135 and 54-146234 can be used.

  As an acidic solution which is an electrolytic solution, in addition to nitric acid and hydrochloric acid, U.S. Pat. Nos. 4,671,859, 4,661,219, 4,618,405, 4,600, 482, 4,566,960, 4,566,958, 4,566,959, 4,416,972, 4,374,710, The electrolyte solution described in each specification of 4,336,113 and 4,184,932 can also be used.

  The concentration of the acidic solution is preferably 0.5 to 2.5% by mass, but it is particularly preferably 0.7 to 2.0% by mass in consideration of use in the smut removal treatment. Moreover, it is preferable that liquid temperature is 20-80 degreeC, and it is more preferable that it is 30-60 degreeC.

  An aqueous solution mainly composed of hydrochloric acid or nitric acid is an aqueous solution of hydrochloric acid or nitric acid having a concentration of 1 to 100 g / L, such as nitric acid compounds having nitrate ions such as aluminum nitrate, sodium nitrate, ammonium nitrate, or aluminum chloride, sodium chloride, ammonium chloride, etc. At least one of the hydrochloric acid compounds having hydrochloric acid ions can be used by adding in a range from 1 g / L to saturation. Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may melt | dissolve in the aqueous solution which has hydrochloric acid or nitric acid as a main component. Preferably, a solution obtained by adding aluminum chloride, aluminum nitrate or the like to an aqueous solution of hydrochloric acid or nitric acid having a concentration of 0.5 to 2% by mass so that aluminum ions are 3 to 50 g / L is preferably used.

Further, by adding and using a compound capable of forming a complex with Cu, uniform graining is possible even for an aluminum plate containing a large amount of Cu. Examples of the compound capable of forming a complex with Cu include ammonia; hydrogen atom of ammonia such as methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, cyclohexylamine, triethanolamine, triisopropanolamine, EDTA (ethylenediaminetetraacetic acid), etc. And amines obtained by substituting with a hydrocarbon group (aliphatic, aromatic, etc.); metal carbonates such as sodium carbonate, potassium carbonate, potassium hydrogen carbonate and the like. In addition, ammonium salts such as ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium phosphate, and ammonium carbonate are also included.
The temperature is preferably 10-60 ° C, more preferably 20-50 ° C.

  The AC power supply wave used for the electrochemical surface roughening treatment is not particularly limited, and a sine wave, a rectangular wave, a trapezoidal wave, a triangular wave or the like is used, but a rectangular wave or a trapezoidal wave is preferable, and a trapezoidal wave is particularly preferable. A trapezoidal wave means what was shown in FIG. In this trapezoidal wave, the time (TP) until the current reaches a peak from zero is preferably 1 to 3 msec. If it is less than 1 msec, processing irregularities such as chatter marks that occur perpendicular to the traveling direction of the aluminum plate are likely to occur. When TP exceeds 3 msec, especially when a nitric acid electrolyte is used, it is easily affected by trace components in the electrolyte typified by ammonium ions and the like that spontaneously increase by electrolytic treatment, and uniform graining is performed. It becomes hard to be broken. As a result, the stain resistance tends to decrease when a lithographic printing plate is obtained.

A trapezoidal wave alternating current duty ratio of 1: 2 to 2: 1 can be used. However, as described in Japanese Patent Laid-Open No. 5-195300, in an indirect power feeding method in which no conductor roll is used for aluminum. A duty ratio of 1: 1 is preferable.
A trapezoidal AC frequency of 0.1 to 120 Hz can be used, but 50 to 70 Hz is preferable in terms of equipment. When the frequency is lower than 50 Hz, the carbon electrode of the main electrode is easily dissolved, and when the frequency is higher than 70 Hz, it is easily affected by an inductance component on the power supply circuit, and the power supply cost is increased.

  One or more AC power supplies can be connected to the electrolytic cell. As shown in FIG. 3, the current ratio between the AC anode and cathode applied to the aluminum plate facing the main electrode is controlled to achieve uniform graining and to dissolve the carbon of the main electrode. In addition, it is preferable to install an auxiliary anode and divert part of the alternating current. In FIG. 3, 11 is an aluminum plate, 12 is a radial drum roller, 13a and 13b are main poles, 14 is an electrolytic treatment liquid, 15 is an electrolytic solution supply port, and 16 is a slit. , 17 is an electrolyte passage, 18 is an auxiliary anode, 19a and 19b are thyristors, 20 is an AC power source, 40 is a main electrolytic cell, and 50 is an auxiliary anode cell. An anodic reaction that acts on the aluminum plate facing the main electrode by diverting a part of the current value as a direct current to an auxiliary anode provided in a tank separate from the two main electrodes via a rectifier or switching element It is possible to control the ratio between the current value for the current and the current value for the cathode reaction. On the aluminum plate facing the main electrode, the ratio of the amount of electricity involved in the anodic reaction and the cathodic reaction (the amount of electricity at the time of cathode / the amount of electricity at the time of anode) is preferably 0.3 to 0.95.

  As the electrolytic cell, electrolytic cells used for known surface treatments such as a vertical type, a flat type, and a radial type can be used, but a radial type electrolytic cell as described in JP-A-5-195300 is particularly preferable. . The electrolytic solution passing through the electrolytic cell may be parallel to the traveling direction of the aluminum web or may be a counter.

(Nitric acid electrolysis)
Fine irregularities can be formed on the surface by an electrochemical surface roughening treatment using an electrolytic solution mainly composed of nitric acid.
The fine irregularities have an average opening diameter of 0.1 to 5 μm and are uniformly generated on the entire surface of the aluminum plate. To obtain such a grain, the total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed is preferably from ^{1~1000C / dm 2, 50~300C / dm} 2 It is more preferable that The current density at this time is preferably ²⁰ to 100 A / dm ² .

(Hydrochloric acid electrolysis)
Since hydrochloric acid itself has a strong ability to dissolve aluminum, it is possible to form fine irregularities on the surface with only slight electrolysis. The finer irregularities have an average opening diameter of 0.01 to 0.2 μm and are uniformly generated on the entire surface of the aluminum plate. Such grained total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed in order to obtain the, is preferably from 1~100C / dm ^2, in 20~70C / dm ² More preferably. The current density at this time is preferably ²⁰ to 50 A / dm ² .

In such an electrochemical surface roughening treatment with an electrolyte mainly composed of hydrochloric acid, a large crater-like swell is simultaneously formed by increasing the total amount of electricity involved in the anode reaction to 400 to 1000 C / dm ^2. In this case, fine irregularities having an average opening diameter of 0.01 to 0.4 μm are formed on the entire surface by being superimposed on a crater-like wave having an average opening diameter of 10 to 30 μm.

  In the present invention, as the first electrochemical surface roughening treatment, the electrochemical surface roughening treatment (nitric acid electrolysis) using the above-described electrolyte mainly composed of nitric acid is performed, and the second electrochemical surface roughening treatment is performed. As the surface treatment, it is preferable to perform the electrochemical surface roughening treatment (hydrochloric acid electrolysis) using the above-described electrolyte mainly composed of hydrochloric acid. That is, the present invention also provides a method for producing a lithographic printing plate support, in which at least an aluminum plate is subjected to nitric acid electrolysis and hydrochloric acid electrolysis sequentially as a roughening treatment, and further subjected to an anodic oxidation treatment to obtain a lithographic printing plate support. provide.

The aluminum plate is preferably subjected to cathodic electrolysis during the first and second electrochemical surface roughening treatments performed in the electrolytic solution such as nitric acid or hydrochloric acid. By this cathodic electrolysis treatment, smut is generated on the surface of the aluminum plate, and hydrogen gas is generated to enable a more uniform electrochemical surface roughening treatment. This cathodic electrolysis treatment is carried out in an acidic solution at a cathode electric quantity of preferably 3 to 80 C / dm ² , more preferably 5 to 30 C / dm ² . If the amount of cathodic electricity is less than 3 C / dm ² , the amount of smut adhesion may be insufficient, and if it exceeds 80 C / dm ² , the amount of smut adhesion may be excessive. Further, the electrolytic solution may be the same as or different from the solution used in the first and second electrochemical roughening treatments.

<Alkaline etching treatment>
The alkali etching treatment is a treatment for dissolving the surface layer by bringing the aluminum plate into contact with an alkali solution.

  Alkaline etching treatment that is performed before the electrochemical surface roughening treatment, when mechanical surface roughening treatment is not performed, is the rolling oil, dirt, natural oxide film, etc. on the surface of the aluminum plate (rolled aluminum). For the purpose of removing the surface, and when the mechanical surface roughening treatment has already been performed, the edge portion of the unevenness generated by the mechanical surface roughening treatment is dissolved to change the surface to a surface with reduced steepness. It is done for the purpose.

If you do not mechanical surface-roughening treatment before the alkali etching treatment, the etching amount is preferably from 0.1 to 10 g / m ^2, and more preferably 1 to 5 g / m ^2. If the etching amount is less than 0.1 g / m ² , rolling oil, dirt, natural oxide film, etc. may remain on the surface, so uniform pits cannot be generated in the subsequent electrochemical roughening treatment. Unevenness may occur. On the other hand, when the etching amount is 1 to 10 g / m ² , the surface rolling oil, dirt, natural oxide film and the like are sufficiently removed. An etching amount exceeding the above range is economically disadvantageous.

When performing mechanical surface-roughening treatment before the alkali etching treatment, the etching amount is preferably from 3 to 20 g / m ^2, and more preferably 5 to 15 g / m ^2. If the etching amount is less than 3 g / m ² , the unevenness formed by mechanical surface roughening may not be smoothed, and uniform pit formation may not be possible in subsequent electrolytic treatment. In addition, the stain may deteriorate during printing. On the other hand, when the etching amount exceeds 20 g / m ² , the concavo-convex structure may disappear.

Alkaline etching treatment performed immediately after the electrochemical surface roughening treatment is performed by dissolving the smut formed in the acidic electrolyte and dissolving the edge portion of the pit formed by the electrochemical surface roughening treatment. The purpose is to reduce the degree a45.
Since the pits formed by the electrochemical surface roughening process differ depending on the type of the electrolytic solution, the optimum etching amount also varies. However, the etching amount of the alkali etching process performed after the electrochemical surface roughening process is 0.1. It is preferably ˜5 g / m ² . When a nitric acid electrolyte is used, the etching amount needs to be set larger than when a hydrochloric acid electrolyte is used.
When the electrochemical surface roughening treatment is performed a plurality of times, an alkali etching treatment can be performed as necessary after each treatment.

  Examples of the alkali used in the alkaline solution include caustic alkali and alkali metal salts. Specifically, examples of caustic alkali include caustic soda and caustic potash. Examples of the alkali metal salt include alkali metal silicates such as sodium metasilicate, sodium silicate, potassium metasilicate, and potassium silicate; alkali metal carbonates such as sodium carbonate and potassium carbonate; sodium aluminate and alumina. Alkali metal aluminates such as potassium acid; alkali metal aldones such as sodium gluconate and potassium gluconate; dibasic sodium phosphate, dibasic potassium phosphate, tribasic sodium phosphate, tertiary potassium phosphate, etc. An alkali metal hydrogen phosphate is mentioned. Among these, a caustic alkali solution and a solution containing both a caustic alkali and an alkali metal aluminate are preferable from the viewpoint of high etching rate and low cost. In particular, an aqueous solution of caustic soda is preferable.

  Although the density | concentration of an alkaline solution can be determined according to the etching amount, it is preferable that it is 1-50 mass%, and it is more preferable that it is 10-35 mass%. When aluminum ions are dissolved in the alkaline solution, the concentration of aluminum ions is preferably 0.01 to 10% by mass, and more preferably 3 to 8% by mass. The temperature of the alkaline solution is preferably 20 to 90 ° C. The treatment time is preferably 1 to 120 seconds.

  Examples of the method of bringing the aluminum plate into contact with the alkaline solution include, for example, a method in which the aluminum plate is passed through a tank containing the alkaline solution, a method in which the aluminum plate is immersed in a tank containing the alkaline solution, The method of spraying on the surface of a board is mentioned.

<Desmut treatment>
After the electrochemical surface roughening treatment or the alkali etching treatment, pickling (desmut treatment) is preferably performed in order to remove dirt (smut) remaining on the surface. Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid.
The desmutting treatment is performed, for example, by bringing the aluminum plate into contact with an acidic solution having a concentration of 0.5 to 30% by mass (containing 0.01 to 5% by mass of aluminum ions) such as hydrochloric acid, nitric acid, and sulfuric acid. . Examples of the method of bringing the aluminum plate into contact with the acidic solution include a method in which the aluminum plate is passed through a tank containing the acidic solution, a method in which the aluminum plate is immersed in a tank containing the acidic solution, and the acidic solution being aluminum. The method of spraying on the surface of a board is mentioned.
In the desmutting treatment, as an acidic solution, a waste solution of an aqueous solution mainly containing nitric acid or an aqueous solution mainly containing hydrochloric acid discharged in the electrochemical surface roughening treatment described above, or sulfuric acid discharged in an anodic oxidation treatment described later A waste solution of an aqueous solution mainly composed of can be used.
It is preferable that the liquid temperature of a desmut process is 25-90 degreeC. Moreover, it is preferable that processing time is 1-180 second. Aluminum and aluminum alloy components may be dissolved in the acidic solution used for the desmut treatment.

<Anodizing treatment>
The aluminum plate treated as described above is preferably further subjected to an anodizing treatment. The anodizing treatment can be performed by a method conventionally used in this field. In this case, for example, in a solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less, an aluminum plate can be energized as an anode to form an anodized film. As a solution used for the anodizing treatment, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid and the like can be used alone or in combination of two or more.

  Under the present circumstances, the component normally contained at least in an aluminum plate, an electrode, tap water, groundwater, etc. may be contained in electrolyte solution. Furthermore, the 2nd, 3rd component may be added. Examples of the second and third components herein include metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn; Cation such as ammonium ion; anion such as nitrate ion, carbonate ion, chloride ion, phosphate ion, fluoride ion, sulfite ion, titanate ion, silicate ion, borate ion, etc., 0 to 10,000 ppm It may be contained at a concentration of about.

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, the electrolyte concentration is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 0.5. ˜60 A / dm ² , voltage 1 to 100 V, electrolysis time 15 seconds to 50 minutes are appropriate, and the amount of anodic oxide film is adjusted as desired.

  Further, JP-A-54-81133, JP-A-57-47894, JP-A-57-51289, JP-A-57-51290, JP-A-57-54300, JP-A-57-136596, JP-A-58-107498, JP-A-60-200366, JP-A-62-136696, JP-A-63-176494, JP-A-4-17697, JP-A-4-280997, JP-A-6-280997 The methods described in JP-A-207299, JP-A-5-24377, JP-A-5-32083, JP-A-5-125597, JP-A-5-195291 and the like can also be used.

  Of these, as described in JP-A-54-12853 and JP-A-48-45303, it is preferable to use a sulfuric acid solution as the electrolytic solution. The sulfuric acid concentration in the electrolytic solution is preferably 10 to 300 g / L (1 to 30% by mass), and the aluminum ion concentration is 1 to 25 g / L (0.1 to 2.5% by mass). It is preferable that it is 2 to 10 g / L (0.2 to 1% by mass). Such an electrolytic solution can be prepared, for example, by adding aluminum sulfate or the like to dilute sulfuric acid having a sulfuric acid concentration of 50 to 200 g / L.

When anodizing is performed in an electrolytic solution containing sulfuric acid, direct current may be applied between the aluminum plate and the counter electrode, or alternating current may be applied.
When a direct current is applied to the aluminum plate, the current density is preferably from 1 to 60 A / dm ^2, and more preferably 5 to 40 A / dm ^2.
In the case where continuous anodizing treatment is performed, a low current of 5 to 10 A / m ² is initially introduced so that current is concentrated on a part of the aluminum plate and so-called “burning” does not occur. It is preferable to increase the current density to 30 to 50 A / dm ² or more as the current is passed at the density and the anodization process proceeds.
When the anodizing process is continuously performed, it is preferable to perform the liquid feeding method in which the aluminum plate is fed with an electrolyte.
By performing anodizing treatment under such conditions, a porous film having many pores called micropores can be obtained. Usually, the average pore diameter is about 5 to 50 nm, and the average pore density is 300. ˜800 / μm ² or so.

The amount of the anodized film is preferably 1 to 5 g / m ² . If it is less than 1 g / m ² , the plate tends to be damaged, whereas if it exceeds 5 g / m ² , a large amount of electric power is required for production, which is economically disadvantageous. The amount of the anodized film is more preferably 1.5 to 4 g / m ² . Moreover, it is preferable that the difference in the amount of the anodized film between the central portion of the aluminum plate and the vicinity of the edge portion is 1 g / m ² or less.

As the electrolysis apparatus used for the anodizing treatment, those described in JP-A-48-26638, JP-A-47-18739, JP-B-58-24517, and the like can be used.
Among these, the apparatus shown in FIG. 4 is preferably used. FIG. 4 is a schematic view showing an example of an apparatus for anodizing the surface of an aluminum plate. In the anodizing apparatus 410, the aluminum plate 416 is transported as indicated by arrows in FIG. In the power supply tank 412 in which the electrolytic solution 418 is stored, the aluminum plate 416 is charged to (+) by the power supply electrode 420. The aluminum plate 416 is conveyed upward by the roller 422 in the power supply tank 412, changed in direction downward by the nip roller 424, and then conveyed toward the electrolytic treatment tank 414 in which the electrolytic solution 426 is stored. The direction is changed horizontally. Next, the aluminum plate 416 is charged to (−) by the electrolytic electrode 430 to form an anodized film on the surface thereof, and the aluminum plate 416 exiting the electrolytic treatment tank 414 is conveyed to a subsequent process. In the anodizing apparatus 410, the roller 422, the nip roller 424, and the roller 428 constitute a direction changing means, and the aluminum plate 416 is disposed between the power supply tank 412 and the electrolytic treatment tank 414 in the inter-tank section. By 428, it is conveyed into a mountain shape and an inverted U shape. The feeding electrode 420 and the electrolytic electrode 430 are connected to a DC power source 434.

  A feature of the anodizing apparatus 410 in FIG. 4 is that the feeding tank 412 and the electrolytic treatment tank 414 are partitioned by a single tank wall 432, and the aluminum plate 416 is conveyed in a mountain shape and an inverted U shape between the tanks. It is in. As a result, the length of the aluminum plate 416 in the inter-tank portion can be minimized. Therefore, the overall length of the anodizing apparatus 410 can be shortened, so that the equipment cost can be reduced. In addition, by conveying the aluminum plate 416 in a mountain shape and an inverted U shape, it is not necessary to form an opening for allowing the aluminum plate 416 to pass through the tank walls of the tanks 412 and 414. Therefore, since the liquid feeding amount required to maintain the liquid level height in each tank 412 and 414 at a required level can be suppressed, the operating cost can be reduced.

<Sealing treatment>
In this invention, you may perform the sealing process which seals the micropore which exists in an anodic oxide film as needed. The sealing treatment can be performed according to a known method such as boiling water treatment, hot water treatment, steam treatment, sodium silicate treatment, nitrite treatment, ammonium acetate treatment and the like. For example, even if the sealing treatment is carried out by the apparatus and method described in JP-B-56-12518, JP-A-4-4194, JP-A-5-20296, JP-A-5-179482, etc. Good.

<Alkali metal silicate treatment>
In the present invention, as described above, the aluminum plate is subjected to a treatment such as roughening treatment or anodizing treatment as necessary, and then subjected to a hydrophilization treatment with an alkali metal silicate aqueous solution (alkali metal silicate). Salt treatment).
The alkali metal silicate treatment can be performed according to the methods and procedures described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461, but in the present invention The Si amount on the surface of the lithographic printing plate support is 3.0 to 15.0 mg / m ² , preferably 3.5 to 10.0 mg / m ² , more preferably 4.0 to 8.0 mg / m. ² , more preferably 4.5 to 6.5 mg / m ² . When the Si amount is 3.0 mg / m ² or more, the entanglement stain resistance is good, and when the Si amount is 15.0 mg / m ² or less, the printing durability is good.
In addition, when the Si amount on the surface of the lithographic printing plate support is in the above range, the entanglement stain resistance is excellent even when the supply amount of dampening water is reduced when printing using an FM screen for halftone dots. It will be. In addition, printing durability, erasure stain resistance and neglected stain resistance are excellent.

  The present inventor has increased the amount of Si on the surface of the support for a lithographic printing plate within the above range while improving the hydrophilicity, while ensuring an excellent printing durability by providing an intermediate layer described later. Even when an FM screen is used, it has been found for the first time that the printing durability is excellent, the occurrence of entanglement stains can be suppressed, and the occurrence of erasure stains and neglected stains can be suppressed. It was made to.

In the present invention, the amount of Si on the surface of the support for a lithographic printing plate is determined as a Si atom adhesion amount (Simg / m ² ) by a calibration curve method using an X-ray Fluorescence Spectrometer (XRF). Use the measured value. As a standard sample for preparing a calibration curve, a sodium silicate aqueous solution containing a known amount of Si atoms is uniformly dropped into an area of 30 mmφ on an aluminum plate and then dried. The model of the X-ray fluorescence analyzer and other conditions are not particularly limited. An example of conditions for X-ray fluorescence analysis of Si is shown below.

  X-ray fluorescence analyzer: RIX3000 manufactured by Rigaku Corporation, X-ray tube: Rh, measurement spectrum: Si-Kα, tube voltage: 50 kV, tube current: 50 mA, slit: COARSE, spectral crystal: RX4, detector: F -PC, analysis area: 30 mmφ, peak position (2θ): 144.75 deg. , Background (2θ): 140.70 deg. And 146.85 deg. Integration time: 80 seconds / sample

The alkali metal silicate used for the alkali metal silicate treatment is not particularly limited, and examples thereof include sodium silicate, potassium silicate, and lithium silicate. These may be used alone or in combination of two or more. The aqueous solution of alkali metal silicate may contain an appropriate amount of sodium hydroxide, potassium hydroxide, lithium hydroxide or the like.
Moreover, the alkali metal silicate aqueous solution may contain an alkaline earth metal salt or a Group 4 (Group IVA) metal salt. Examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; oxalates; Examples of the Group 4 (Group IVA) metal salt include titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride. And zirconium tetrachloride. These alkaline earth metal salts and Group 4 (Group IVA) metal salts are used alone or in combination of two or more.

  The alkali metal silicate treatment is performed by bringing an aluminum plate subjected to a treatment such as a roughening treatment or an anodizing treatment into contact with an alkali metal silicate aqueous solution. The method of bringing the aluminum plate into contact with the alkali metal silicate aqueous solution is not particularly limited. For example, the method of passing the aluminum plate through the tank containing the aqueous solution, and the aluminum plate in the tank containing the aqueous solution. Examples include a dipping method and a method of spraying the aqueous solution onto the surface of an aluminum plate.

  The conditions for the alkali metal silicate treatment are not particularly limited as long as the Si amount falls within the above range, but the liquid temperature is preferably 10 to 80 ° C, more preferably 15 to 50 ° C, and more preferably 20 to 20 ° C. More preferably, it is 40 degreeC. The treatment time is preferably 1 to 100 seconds, more preferably 2 to 20 seconds, and further preferably 3 to 10 seconds.

The alkali metal silicate treatment is performed using an alkali metal silicate aqueous solution having a pH of 11.5 to 13.0. The aqueous alkali metal silicate solution preferably has a pH of 11.7 to 12.5, more preferably a pH of 11.8 to 12.3. Within the above range, even when an FM screen is used for the halftone dots, the printing durability, entanglement stain resistance, erasure stain resistance, and neglected stain resistance are excellent. If the pH is 11.5 or more, the entanglement stain resistance is good even when an FM screen is used for the halftone dots, and the neglectable stain resistance is good if the pH is 13.0 or less.
The reason for this is not clear, but when the pH is in the above range, the amount of Si increases and the amount of silanol groups (SiOH) present on the surface of the aluminum plate increases, resulting in higher hydrophilicity. Conceivable.

  The method of adjusting the pH to the above range is not particularly limited. For example, a method of adding a strong alkali such as sodium hydroxide, potassium hydroxide, lithium hydroxide or the like to an aqueous alkali metal silicate solution, an alkali metal silicate, for example. A method of increasing the concentration of Among these, a method of adding sodium hydroxide is preferable.

  The concentration of the aqueous alkali metal silicate solution is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass, and further preferably 2 to 6% by mass.

<Washing treatment>
It is preferable to perform water washing after the completion of the above-described processes. For washing with water, pure water, well water, tap water, or the like can be used, and water containing Ca is preferably used. Further, a nip device may be used to prevent the processing liquid from being brought into the next process.

<Back coat layer>
The support for a lithographic printing plate obtained as described above has a back surface (a surface on which the image recording layer is not provided) so that the image recording layer is not damaged even if it is overlaid when a lithographic printing plate precursor is used. ) May be provided with a coating layer made of an organic polymer compound (hereinafter also referred to as “backcoat layer”) as necessary.
As a main component of the back coat layer, at least one resin selected from the group consisting of a saturated copolymerized polyester resin, a phenoxy resin, a polyvinyl acetal resin, and a vinylidene chloride copolymer resin having a glass transition point of 20 ° C. or higher is used. Is preferred.

  The saturated copolyester resin is composed of a dicarboxylic acid unit and a diol unit. Examples of the dicarboxylic acid unit include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, tetrabromophthalic acid, and tetrachlorophthalic acid; adipic acid, azelaic acid, succinic acid, oxalic acid, suberic acid, and sebacic acid , Saturated aliphatic dicarboxylic acids such as malonic acid and 1,4-cyclohexanedicarboxylic acid.

  The backcoat layer further comprises a dye or pigment for coloring, a silane coupling agent for improving the adhesion to the support, a diazo resin comprising a diazonium salt, an organic phosphonic acid, an organic phosphoric acid, a cationic polymer, Wax, higher fatty acids, higher fatty acid amides, silicone compounds composed of dimethylsiloxane, modified dimethylsiloxane, polyethylene powder and the like that are usually used as slipping agents can be appropriately contained.

  The thickness of the backcoat layer may be basically such that even if no interleaf is present, the image recording layer to be described later is hardly damaged, and is preferably 0.01 to 8 μm. When the thickness is less than 0.01 μm, it is difficult to prevent the recording layer from being scratched when the planographic printing plate precursors are handled in layers. On the other hand, when the thickness exceeds 8 μm, the backcoat layer swells due to chemicals used around the lithographic printing plate during printing, the thickness varies, and the printing pressure may change to deteriorate the printing characteristics.

  Various methods can be used as a method of providing the back coat layer on the back surface of the support. For example, a method in which the above components for the back coat layer are dissolved in an appropriate solvent and applied as a solution, or an emulsified dispersion is applied and dried; a previously formed film is supported with an adhesive or heat. The method of bonding to a body; The method of forming a molten film with a melt extruder and bonding to a support body is mentioned. The most preferable method for securing a suitable thickness is a method in which the components for the backcoat layer are dissolved in a suitable solvent, applied as a solution, and dried. In this method, an organic solvent as described in JP-A-62-251739 can be used alone or in combination as a solvent.

  In the production of a lithographic printing plate precursor, any one of the back-coat layer on the back surface, the intermediate layer on the front surface, and the image recording layer may be provided on the support first, or both may be provided simultaneously.

<Surface shape of aluminum plate>
The surface of the aluminum plate treated as described above preferably has a surface area ratio ΔS of 10 to 50% and a steepness a45 of 5 to 40%.
When the surface area ratio ΔS and the steepness a45 are within the above ranges, the printing durability when an FM screen is used for the halftone dots is further improved.

However, the surface area ratio ΔS is obtained by measuring the actual area S _x obtained by the approximate three-point method from the three-dimensional data obtained by measuring 512 × 512 points of the surface 50 μm □ using an atomic force microscope, and geometric measurement. The area S ₀ is a value obtained by the following formula (1), and the steepness a45 is an area ratio of a portion having an inclination with an angle of 45 ° or more with respect to the actual area S _x (an inclination of 45 ° or more). It is.

ΔS = (S _x −S ₀ ) / S ₀ × 100 (%) (1)

The surface area ratio ΔS is more preferably 15 to 50%, and further preferably 20 to 50%.
The steepness a45 is more preferably 5 to 30%, and further preferably 5 to 25%.

  The surface area ratio ΔS and the steepness a45 are obtained by the method described below.

(I) Measurement of surface shape with atomic force microscope First, the surface shape is measured with an atomic force microscope (AFM) to obtain three-dimensional data (f (x, y)).
The measurement can be performed, for example, under the following conditions. That is, the lithographic printing plate support is cut to a size of 1 cm square, set on a horizontal sample stage on a piezo scanner, the cantilever is approached to the sample surface, and when the region where the atomic force works is reached, XY Scanning in the direction, the unevenness of the sample is captured by the displacement of the piezo in the Z direction. A piezo scanner that can scan 150 μm in the XY direction and 10 μm in the Z direction is used. The cantilever has a resonance frequency of 120 to 150 kHz and a spring constant of 12 to 20 N / m (for example, SI-DF20, manufactured by Seiko Instruments Inc .; NCH-10, manufactured by NANOSENSORS; or AC-160TS, manufactured by Olympus Corporation) Measured in DFM mode (Dynamic Force Mode). Further, the reference plane is obtained by correcting the slight inclination of the sample by approximating the obtained three-dimensional data by least squares.
At the time of measurement, a surface of 50 μm □ is measured at 512 × 512 points. The resolution in the XY direction is 1.9 μm, the resolution in the Z direction is 1 nm, and the scan speed is 60 μm / sec.

(Ii) Calculation of surface area ratio ΔS Using three-dimensional data (f (x, y)) based on the measurement of 50 μm □ of the surface obtained in (i) above, three adjacent points are extracted, The total area of the formed small triangles is obtained and set as the actual area S _x . The surface area ratio ΔS is obtained by the above formula (1) from the obtained real area S _x and the geometric measurement area S ₀ .

(Iii) Calculation of steepness a45 Using the three-dimensional data (f (x, y)) obtained in (i) above, each reference point and two adjacent points in a predetermined direction (for example, right and bottom) The angle formed by the small triangle formed by the three points and the reference plane is calculated for each reference point. The number of reference points whose inclination of the micro triangle is 45 degrees or more is obtained by subtracting the number of all reference points (the number of all data 512 × 512 points and the number of points having no two adjacent points in a predetermined direction). In other words, the area ratio a45 of the portion having the inclination of 45 degrees or more is calculated by dividing by 511 × 511 points.

[Middle layer]
Next, the intermediate layer will be described.
The intermediate layer is formed using a polymer material including a component having an acid group and a component having an onium group. By forming an intermediate layer using the polymer compound on the above-described lithographic printing plate support, the lithographic printing plate precursor of the present invention has printing durability, anti-stain resistance and erasure anti-staining property. Become good. This polymer compound is formed, for example, by polymerizing at least an acid group-containing monomer and an onium group-containing monomer. Hereinafter, this polymer compound will be described in detail.

The acid group is preferably an acid group having an acid dissociation index (pKa) of 7 or less, more preferably —COOH, —SO ₃ H, —OSO ₃ H, —PO ₃ H ₂ , —OPO ₃ H ₂ , —CONHSO. ₂ , —SO ₂ NHSO ₂ —, particularly preferably —COOH.
Moreover, what is preferable as an onium group is an onium group containing an atom of Group 15 (Group VA) or Group 16 (Group VIA) of the periodic table, more preferably a nitrogen atom, a phosphorus atom or a sulfur atom. Particularly preferred is an onium group containing a nitrogen atom.

  The polymer used in the present invention is preferably a polymer compound characterized in that the main chain structure is a vinyl polymer such as acrylic resin, methacrylic resin or polystyrene, urethane resin, polyester or polyamide. More preferably, it is a polymer compound characterized in that the main chain structure of the polymer is a vinyl polymer such as an acrylic resin, a methacrylic resin or polystyrene. Particularly preferably, the monomer having an acid group is a compound represented by the following general formula (1) or general formula (2), and the monomer having an onium group is a general formula (3) or general formula (4) described later. Or it is a polymer compound characterized by being a compound represented by General formula (5).

In the formula, A represents a divalent linking group. B represents an aromatic group or a substituted aromatic group. D and E each independently represent a divalent linking group. G represents a trivalent linking group. X and X ′ each independently represents an acid group having a pKa of 7 or less, or an alkali metal salt or ammonium salt thereof. R ₁ represents a hydrogen atom, an alkyl group or a halogen atom. a, b, d and e each independently represents 0 or 1; t is an integer of 1 to 3.

More preferably among the monomers having an acid group, A represents —COO— or —CONH—, B represents a phenylene group or a substituted phenylene group, and the substituent is a hydroxyl group, a halogen atom or an alkyl group. D and E each independently represent an alkylene group or a divalent linking group having a molecular formula of C _n H _2n O, C _n H _2n S or C _n H _{2n + 1} N. G represents a trivalent connecting group molecular formula is represented by _{C n H 2n-1, C} n H 2n-1 O, C n H 2n-1 S or C _n H _2n N. However, n represents the integer of 1-12 here. X and X ′ each independently represent a carboxylic acid, a sulfonic acid, a phosphonic acid, a sulfuric monoester or a phosphoric monoester. R ₁ represents a hydrogen atom or an alkyl group. a, b, d and e each independently represent 0 or 1, but a and b are not 0 at the same time. Among the monomers having an acid group, a compound represented by the general formula (1) is particularly preferable, and B represents a phenylene group or a substituted phenylene group, and the substituent is a hydroxyl group or an alkyl group having 1 to 3 carbon atoms. D and E each independently represent an alkylene group having 1 to 2 carbon atoms or an alkylene group having 1 to 2 carbon atoms linked by an oxygen atom. R ₁ represents a hydrogen atom or an alkyl group. X represents a carboxylic acid group. a is 0 and b is 1.

Specific examples of the monomer having an acid group are shown below. However, the present invention is not limited to this specific example.
(Specific examples of monomers having acid groups)
Acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, itaconic acid, maleic acid, maleic anhydride

  Next, the polymer represented by the following general formula (13), (14) or (15), which is a monomer having an onium group, will be described.

In the formula, J represents a divalent linking group. K represents an aromatic group or a substituted aromatic group. M independently represents a divalent linking group. Y ₁ represents an atom of the periodic table 15 group (Group VA), and Y ₂ represents an atom of the periodic table group 16 (Group VIA). Z ⁻ represents a counter anion. R ₂ represents a hydrogen atom, an alkyl group or a halogen atom. R ₃ , R ₄ , R ₅ and R ₇ each independently represents a hydrogen atom or, optionally, an alkyl group, aromatic group or aralkyl group to which a substituent may be bonded, and R ₆ represents an alkylidine group or a substituted group. Although it represents alkylidine, R ₃ and R ₄ or R ₆ and R ₇ may be bonded to each other to form a ring. j, k and m each independently represents 0 or 1; u represents an integer of 1 to 3.

More preferably among the monomers having an onium group, J represents —COO— or —CONH—, K represents a phenylene group or a substituted phenylene group, and the substituent is a hydroxyl group, a halogen atom or an alkyl group. M represents an alkylene group or a divalent linking group having a molecular formula of C _n H _2n O, C _n H _2n S, or C _n H _{2n + 1} N. However, n represents the integer of 1-12 here. Y ₁ represents a nitrogen atom or a phosphorus atom, and Y ₂ represents a sulfur atom. Z ⁻ represents a halogen ion, PF ₆ ⁻ , BF ₄ ⁻ or R ₈ SO ₃ ⁻ . R ₂ represents a hydrogen atom or an alkyl group. R ₃ , R ₄ , R ₅ and R ₇ each independently represent a hydrogen atom or, optionally, a C 1-10 alkyl group, aromatic group or aralkyl group to which a substituent may be bonded; ₆ represents an alkylidine group having 1 to 10 carbon atoms or a substituted alkylidine, but R ₃ and R ₄ , and R ₆ and R ₇ may be bonded to each other to form a ring. j, k and m each independently represent 0 or 1, but j and k are not 0 at the same time. R ₈ represents a C 1-10 alkyl group, aromatic group or aralkyl group to which a substituent may be bonded.

More preferably among monomers having an onium group, K represents a phenylene group or a substituted phenylene group, and the substituent is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. M represents an alkylene group having 1 to 2 carbon atoms or an alkylene group having 1 to 2 carbon atoms linked by an oxygen atom. Z ⁻ represents a chlorine ion or R ₈ SO ₃ ^— . R ₂ represents a hydrogen atom or a methyl group. j is 0 and k is 1. R ₈ represents an alkyl group having 1 to 3 carbon atoms.

Specific examples of the monomer having an onium group are shown below. However, the present invention is not limited to this specific example.
(Specific examples of monomers having an onium group)

Monomers having an acid group may be used alone or in combination of two or more, and monomers having an onium group may be used alone or in combination of two or more. Furthermore, the polymer used in the present invention may be a mixture of two or more monomers having different monomers, composition ratios or molecular weights.
The polymer used in the present invention preferably contains 60 to 80 mol%, more preferably 65 to 75 mol% of a component having an acid group. Moreover, it is preferable to contain 20-40 mol% of the structural component which has an onium group, and it is more preferable to contain 25-35 mol%.
When the polymer contains the constituent component having an acid group and the constituent component having an onium group in the above range, the obtained lithographic printing plate precursor is further improved in printing durability.

  In addition, the structural component which has an acid group may be used independently or may be used in combination of 2 or more types, and the monomer which has onium group may be used independently or may be used in combination of 2 or more types. Furthermore, the polymers used in the present invention may be used in admixture of two or more types having different monomers, composition ratios or molecular weights.

Furthermore, these polymers may contain at least one selected from the polymerizable monomers shown in the following (1) to (14) as a copolymerization component.
(1) N- (4-hydroxyphenyl) acrylamide or N- (4-hydroxyphenyl) methacrylamide, o-, m- or p-hydroxystyrene, o- or m-bromo-p-hydroxystyrene, o- or Acrylamides, methacrylamides, acrylates, methacrylates and bidroxystyrenes having an aromatic hydroxyl group such as m-chloro-p-hydroxystyrene, o-, m- or p-hydroxyphenyl acrylate or methacrylate ,
(2) unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride and its half ester, itaconic acid, itaconic anhydride and its half ester,

  (3) 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-aminosulfonylphenyl) methacryl Amides, methacrylamides such as N- [1- (3-aminosulfonyl) naphthyl] methacrylamide, N- (2-aminosulfonylethyl) methacrylamide, o-aminosulfonylphenyl acrylate, m-aminosulfonylphenyl Unsaturated sulfonamides such as acrylic acid esters such as acrylate, p-aminosulfonylphenyl acrylate, 1- (3-aminosulfonylphenylnaphthyl) acrylate, o-aminosulfonylphenyl methacrylate, m-aminosulfonylphenyl methacrylate, p-amino Unsaturated sulfonamides such as sulfonylphenyl methacrylate and methacrylates such as 1- (3-aminosulfonylphenylnaphthyl) methacrylate,

(4) phenylsulfonylacrylamide, which may have a substituent such as tosylacrylamide, and phenylsulfonylmethacrylamide, which may have a substituent such as tosylmethacrylamide;
(5) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group, such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate,
(6) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, cyclohexyl acrylate, octyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, (Substituted) acrylic acid esters such as 4-hydroxybutyl acrylate, glycidyl acrylate, N-dimethylaminoethyl acrylate,
(7) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, octyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, (Substituted) methacrylate esters such as 4-hydroxybutyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl methacrylate,

(8) Acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N-ethyl acrylamide, N-ethyl methacrylamide, N-hexyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-cyclohexyl methacryl Amide, N-hydroxyethylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-phenylmethacrylamide, N-benzylacrylamide, N-benzylmethacrylamide, N-nitrophenylacrylamide, N-nitrophenylmethacrylamide, N Acrylamide or methacrylamide such as ethyl-N-phenylacrylamide and N-ethyl-N-phenylmethacrylamide
(9) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether,

(10) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, vinyl benzoate,
(11) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene,
(12) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, phenyl vinyl ketone,
(13) Olefins such as ethylene, propylene, isobutylene, butadiene, isoprene,
(14) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like.

  Next, typical examples of the polymer used in the present invention are shown below. The composition ratio of the polymer structure represents a mole percentage.

  The polymer used in the present invention can generally be produced using a radical chain polymerization method (see “Textbook of Polymer Science” 3rd ed. (1984) FW Billmeyer, A Wiley-Interscience Publication).

The molecular weight of the polymer used in the present invention may be in a wide range, but when measured using a light scattering method, the weight average molecular weight (M _w ) is preferably from 500 to 2,000,000. More preferably, it is in the range of 1,000,000 to 600,000. Further, the number average molecular weight (M _n ) calculated from the integrated intensity of the terminal group and the side chain functional group in NMR measurement is preferably 300 to 500,000, and is preferably in the range of 500 to 100,000. More preferred. If the molecular weight is smaller than the above range, the adhesion to the substrate is weakened and printing durability may be deteriorated. On the other hand, when the molecular weight exceeds the above range, the adhesion to the support becomes too strong, and the photosensitive layer residue in the non-image area may not be sufficiently removed. The amount of the unreacted monomer contained in the polymer may be in a wide range, but is preferably 20% by mass or less, more preferably 10% by mass or less.

A polymer having a molecular weight in the above range can be obtained by using a polymerization initiator and a chain transfer agent together and adjusting the addition amount when the corresponding monomer is copolymerized. The chain transfer agent refers to a substance that moves the active site of the reaction by a chain transfer reaction in a polymerization reaction, and the ease of the transfer reaction is represented by a chain transfer constant Cs. The chain transfer constant Cs × 10 ⁴ (60 ° C.) of the chain transfer agent used in the present invention is preferably 0.01 or more, more preferably 0.1 or more, and particularly preferably 1 or more. preferable. As the polymerization initiator, peroxides, azo compounds, and redox initiators that are commonly used in radical polymerization can be used as they are. Of these, azo compounds are particularly preferred.

Specific examples of the chain transfer agent include halogen compounds such as carbon tetrachloride and carbon tetrabromide, alcohols such as isopropyl alcohol and isobutyl alcohol, 2-methyl-1-butene, 2,4-diphenyl-4-methyl- Olefins such as 1-pentene, ethanethiol, butanethiol, dodecanethiol, mercaptoethanol, mercaptopropanol, methyl mercaptopropionate, ethyl mercaptopropionate, mercaptopropionic acid, thioglycolic acid, ethyl disulfide, sec-butyl disulfide, 2 -Sulfur-containing compounds such as hydroxyethyl disulfide, thiosalicylic acid, thiophenol, thiocresol, benzyl mercaptan, phenethyl mercaptan and the like are exemplified, but not limited thereto.
More preferably, ethanethiol, butanethiol, dodecanethiol, mercaptoethanol, mercaptopropanol, methyl mercaptopropionate, ethyl mercaptopropionate, mercaptopropionic acid, thioglycolic acid, ethyl disulfide, sec-butyl disulfide, 2-hydroxyethyl disulfide Thiosalicylic acid, thiophenol, thiocresol, benzyl mercaptan, phenethyl mercaptan, particularly preferably ethanethiol, butanethiol, dodecanethiol, mercaptoethanol, mercaptopropanol, methyl mercaptopropionate, ethyl mercaptopropionate, mercaptopropionic acid Thioglycolic acid, ethyl disulfide, sec-butyl disulfide, 2-hydride Carboxymethyl ethyl disulfide.

  The amount of the unreacted monomer contained in the polymer may be in a wide range, but is preferably 20% by mass or less, and more preferably 10% by mass or less.

<Formation of intermediate layer>
The intermediate layer used in the present invention is provided by applying the coating solution (intermediate layer forming coating solution) in which each component of the above-described intermediate layer is dissolved on the above-described lithographic printing plate support by various methods. be able to. Although there is no restriction | limiting in particular in the method of apply | coating an intermediate | middle layer, The following method is mentioned as a typical thing. That is, (1) A solution in which the specific polymer in the present invention is dissolved in an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof, or a mixed solvent of these organic solvent and water is applied onto a support. A coating method provided by drying. Alternatively, (2) the support is immersed in a solution in which the specific polymer in the present invention is dissolved in an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof, or a mixed solvent of these organic solvents and water. Thereafter, a coating method in which the intermediate layer is formed by washing and drying with water or air or the like can be mentioned.

  In the application method (1), a solution having a concentration of 0.005 to 10% by mass in total may be applied by various methods. As the coating means, any means such as bar coater coating, spin coating, spray coating, curtain coating, etc. may be used. In the coating method (2), the concentration of the solution is 0.005 to 20% by mass, preferably 0.01 to 10% by mass, and the immersion temperature is 0 to 70 ° C., preferably 5 to 60 ° C. The soaking time is 0.1 to 5 minutes, preferably 0.5 to 120 seconds.

  The above intermediate layer forming coating solution includes basic substances such as ammonia, triethylamine and potassium hydroxide, inorganic acids such as hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid, organic sulfonic acids such as nitrobenzenesulfonic acid and naphthalenesulfonic acid, PH is adjusted with organic phosphonic acids such as phenylphosphonic acid, organic acidic substances such as organic carboxylic acids such as benzoic acid, coumaric acid and malic acid, naphthalenesulfonyl chloride, organic chlorides such as benzenesulfonyl chloride, etc., pH 0-12, More preferably, it can also be used in the range of pH 0-6. In addition, a substance that absorbs ultraviolet light, visible light, infrared light, or the like can be added to the coating solution for forming an intermediate layer in order to improve the tone reproducibility of the lithographic printing plate.

The total coating amount of the intermediate layer in the present invention after drying is appropriately 1 to 100 mg / m ² , and preferably ² to 70 mg / m ² .
By providing the intermediate layer described above, the lithographic printing plate precursor according to the present invention is also capable of entanglement stain resistance, erasure stain resistance, neglected stain resistance, and printing durability even when an FM screen is used for halftone dots. It will be excellent.

The operation of the intermediate layer used in the present invention is not clear, but when the image recording layer is removed using an erasing liquid, the interaction between the intermediate layer and the aluminum plate is weakened, and the intermediate layer can be easily removed. it is conceivable that.
In general, an image recording layer (thermal positive type image recording layer) containing an alkali-soluble polymer compound and a photothermal conversion substance, which will be described later, is near the support surface due to thermal diffusion to the support during exposure. In some cases, the removal of the image recording layer in the non-image area may be incomplete, but in the present invention, the polymer used for the intermediate layer has good removability by the developer, When a positive type image recording layer is provided, the non-image area is treated with an aqueous solution containing an alkali metal salt having a pH of 11.5 to 13.0, and the aluminum content is 3.0 to 15.0 mg / m ² Since the plate is exposed, it is considered that the occurrence of entangled dirt is effectively suppressed.

[Image recording layer]
As described above, after providing the intermediate layer on the lithographic printing plate support, an image recording layer is further provided to obtain the lithographic printing plate precursor of the present invention. The lithographic printing plate precursor according to the invention comprises the above-described intermediate layer and an image recording layer described later on the above-described lithographic printing plate support in this order, but other layers ( For example, the above-described backcoat layer and an overcoat layer described later) can be provided.

  A photosensitive composition is used for the image recording layer. The photosensitive composition suitably used in the present invention is not particularly limited. For example, a thermal positive photosensitive composition containing an alkali-soluble polymer compound and a photothermal conversion substance (hereinafter referred to as this composition and the composition). The image recording layer was referred to as “thermal positive type”), a thermal negative photosensitive composition containing a curable compound and a photothermal conversion substance (hereinafter also referred to as “thermal negative type”), and photopolymerization type photosensitive. Composition (hereinafter also referred to as “photopolymer type”), negative photosensitive composition containing diazo resin or photocrosslinking resin (hereinafter also referred to as “conventional negative type”), positive containing quinonediazide compound Type photosensitive composition (hereinafter also referred to as "conventional positive type"), photosensitive composition that does not require a special development step (Referred to below as "non-treatment type".) And the like.

Also, as a thermal positive type, a thermal negative type, etc., the digitized image information is carried on a high-convergence radiation such as a laser beam, and the lithographic printing plate precursor is scanned and exposed with the light, via a lith film. Without any problem, it is preferably used in computer-to-plate (CTP) technology for directly producing a lithographic printing plate. Therefore, an image recording layer that can be written by infrared laser exposure and used for such applications is preferable.
Hereinafter, these suitable photosensitive compositions will be described.

<Thermal positive type>
<Photosensitive layer>
The thermal positive type photosensitive composition contains an alkali-soluble polymer compound and a photothermal conversion substance. In the thermal positive type image recording layer, the photothermal conversion substance converts the energy of light such as infrared lasers into heat, which effectively eliminates the interaction that reduces the alkali solubility of alkali-soluble polymer compounds. To do.

Examples of the alkali-soluble polymer compound include a resin containing an acid group in the molecule and a mixture of two or more thereof. In particular, a phenolic hydroxy group, sulfonamide group (in -SO ₂ NH-R (wherein, R represents a hydrocarbon group.)), Active imino group _{(-SO 2 NHCOR, -SO 2 NHSO} 2 R, -CONHSO A resin having an acid group such as ₂ R (wherein R has the same meaning as described above) is preferable in terms of solubility in an alkali developer.
In particular, a resin having a phenolic hydroxy group is preferable in that it has excellent image-forming properties when exposed to light such as an infrared laser. For example, phenol-formaldehyde resin, m-cresol-formaldehyde resin, p-cresol-formaldehyde resin, m- / p-mixed cresol-formaldehyde resin, phenol / cresol (any of m-, p- and m- / p-mixed) mixed-formaldehyde resin (phenol-cresol-formaldehyde co-condensation resin) and other novolak resins Are preferable.
Furthermore, a polymer compound described in JP-A No. 2001-305722 (particularly [0023] to [0042]), and a repetition represented by the general formula (1) described in JP-A No. 2001-215893 Preferred examples also include polymer compounds containing units and polymer compounds described in JP-A No. 2002-311570 (particularly [0107]).

  Preferable examples of the photothermal conversion substance include pigments or dyes having a light absorption region in the infrared region having a wavelength of 700 to 1200 nm from the viewpoint of recording sensitivity. Examples of the dye include azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes (for example, , Nickel thiolate complex). Among these, cyanine dyes are preferable, and cyanine dyes represented by the general formula (I) described in JP 2001-305722 A are particularly preferable.

The thermal positive type photosensitive composition may contain a dissolution inhibitor. As the dissolution inhibitor, for example, dissolution inhibitors described in JP-A-2001-305722, [0053] to [0055] are preferably exemplified.
In addition, in the thermal positive type photosensitive composition, as a additive, a sensitivity modifier, a printing agent for obtaining a visible image immediately after heating by exposure, a compound such as a dye as an image colorant, a coating property In addition, it is preferable to include a surfactant for improving the processing stability. For these, compounds as described in [0056] to [0060] of JP-A No. 2001-305722 are preferable.
The photosensitive composition described in detail in Japanese Patent Application Laid-Open No. 2001-305722 is also preferably used in other respects.

  In the present invention, in addition to the alkali-soluble polymer compound and the photothermal conversion substance, (a) a monomer represented by the following formula (2) (hereinafter referred to as “monomer a”), (b) And a monomer having an aliphatic group having 7 or more carbon atoms having a bridge bond (hereinafter referred to as “monomer b”) and (c) a monomer having an acid group (hereinafter referred to as “monomer c”). It is preferable to contain a high molecular compound fluorine-based polymer (hereinafter referred to as “specific copolymer”) as a component.

In the formula (2), Rf is a substituent containing a fluoroalkyl group or a perfluoroalkyl group having 9 or more fluorine atoms, n is 1 or 2, and R ¹ is hydrogen or a methyl group. .
The bridge-like bond refers to a bond obtained by bonding non-adjacent atoms in one ring structure in a bridging manner. When the monomer b has two or more cycloaliphatic groups, it suffices if at least one has a bridge-like bond.

In lithographic printing, when the amount of dampening water is increased during printing, a phenomenon occurs in which ink does not adhere to the image area or the image density becomes thin. Such a phenomenon is called poor inking.
However, the inclusion of the specific copolymer in the image recording layer allows the lithographic printing plate precursor to adhere ink to the image area regardless of whether the amount of dampening water supplied during printing is large or small. Meat is good. That is, the lithographic printing plate precursor of the present invention can be used in cases where the amount of dampening water is large or small by incorporating the polymer compound fluorine-based polymer in the image recording layer of the lithographic printing plate precursor of the present invention. When the FM screen is used, the entanglement stain resistance is good, and the ink deposits on the image portion is also good. That is, it becomes easier to balance water and ink during printing.

The mechanism of action of the specific copolymer is not clear, but is presumed as follows.
The specific copolymer has a tendency to be unevenly distributed due to the function of the monomer a. At that time, the functional group of the monomer b which is the second copolymer component is also oriented on the surface. Although the partial structure containing fluorine contributes to the improvement of the development resistance, there is a concern that its high oil repellency affects the fleshing property.
However, since the aliphatic group having 7 or more carbon atoms having a bridge-like bond contained in the monomer b is sterically bulky and has a relatively low affinity with a coexisting alkali-soluble resin such as a novolak resin, it is more oriented on the surface. Since this aliphatic group has a high lipophilicity, by copolymerizing the monomer b with a specific copolymer, even if the introduction amount is small, the surface is made highly lipophilic, It is considered that the inking property is improved.

Since this specific copolymer exhibits excellent lipophilicity even if the amount of introduction of an aliphatic group having 7 or more carbon atoms having a bridge-like bond that contributes to lipophilicity is small, this specific copolymer has Can introduce sufficient acid groups to impart alkali solubility. The specific copolymer has excellent alkali solubility due to the monomer c that performs this function. Therefore, the specific copolymer unevenly distributed on the surface becomes soluble in alkali in the exposed area, so that the developability of the image recording layer is sufficient.
Therefore, when the above specific copolymer is used as an image recording layer of a lithographic printing plate precursor, it is possible to provide a lithographic printing plate precursor that is excellent in both ink depositing in the image area and developability in the non-image area. I believe.
Below, a specific copolymer is demonstrated.

<Specific copolymer>
The specific copolymer contains the monomer a represented by the above formula (2).

  Specific examples of the fluorine atom-containing substituent in Rf include the following fluoroalkyl (meth) acrylates.

CH ₂ = CRCO ₂ (CH ₂ ) _m C _n F _{2n + 1}
CH ₂ = CRCO ₂ (CH ₂ ) _m C _n F _2n H
However, m is 1 or 2, n is an integer of 4-12, R is a C1-C4 alkyl group.

Here, by using a fluoroalkyl group or a perfluoroalkyl group represented by Rf having 9 or more fluorine atoms, an image recording layer having a fluorine atom concentration distribution in the film thickness direction, specifically, An image recording layer having a concentration distribution in which the concentration of fluorine atoms near the surface of the image recording layer is high and the concentration of fluorine atoms decreases in the depth direction is formed.
Moreover, 9-30 are preferable and, as for the number of the fluorine atoms per unit in the monomer a, 13-25 are more preferable. When it is in the above range, the effect of orienting the specific copolymer on the surface is exhibited well, and the ink is excellent in the image area.
Moreover, 5-30 mmol / g is preferable and, as for content of the fluorine atom contained in a specific copolymer, 8-25 mmol / g is more preferable. If it is the said range, the oil repellency of a fluorine atom will become appropriate, and the ink deposit property to an image part will become favorable.

The specific copolymer contains the monomer b. Since the aliphatic group having a bridge-like bond contained in the monomer b is present in the vicinity of the surface of the image recording layer, high lipophilicity is imparted to the surface of the image area, and ink inking on the image area is improved. This aliphatic group is bulky compared to those having no bridge-like structure, and has a large number of carbon atoms in the structure, so that it has an affinity for a polymer having an acid group such as a coexisting alkali-soluble resin. It is considered that it can be imparted with excellent lipophilicity to the image-recording layer because it is low and does not embed in the acid group-containing polymer and becomes more easily surface-oriented.
The aliphatic group having 7 or more carbon atoms having a bridge-like bond in the specific copolymer is preferably 0.1 to 10 mmol / g, more preferably 0.2 to 8.0 mmol / g. 0.4 to 5 mmol / g is more preferable. If it is the said range, an image-recording layer will become a thing with high wall property and excellent alkali solubility.

  The monomer b is listed, for example, in Japanese Patent Application Laid-Open No. 2002-311577 filed earlier by the applicant of the present application. Hereinafter, specific examples (b-1) to (b-38) of the monomer b preferable for use in the specific copolymer are shown, but the monomer b is not limited thereto.

The specific copolymer contains the monomer c. The monomer c is not particularly limited as long as it is a compound having at least one polymerizable unsaturated group and acid group in the molecule. The monomer c is an alkali-soluble structural unit.
Among the acid groups, it is preferable to include, as a copolymerization component, monomers having acid groups listed in the following (1) to (6).

(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid groups (hereinafter referred to as “active imide groups”. —SO ₂ NHCOR, —SONHSO ₂ R, —CONHSO ₂ R)
(4) Carboxylic acid group (—CO ₂ H)
(5) Sulfonic acid group (—SO ₃ H)
(6) Phosphate group (—OPO ₃ H ₂ )

Among the above (1) to (6), Ar is a divalent aryl linking group which may have a substituent, and R is a hydrogen atom or a hydrocarbon group which may have a substituent. .
Among the compounds having an acid group selected from the above (1) to (6), those having (1) a phenol group, (2) a sulfonamide group, and (4) a carboxylic acid group are preferable from the viewpoint of effects, (4) Those having a carboxylic acid group are more preferable from the viewpoint of ensuring sufficient inking properties and developability.

  Examples of the monomer (1) having a phenol group include monomers having a hydroxyaryl group in the side chain. Examples of the monomer having a hydroxyaryl group in the side chain include those containing at least one monomer represented by the following formula (a).

However, in formula (a), R ¹¹ represents a hydrogen atom or a methyl group. R ¹² represents a hydrogen atom, a halogen atom, a hydrocarbon group having 10 or less carbon atoms, an alkoxy group having 10 or less carbon atoms, or an aryloxy group having 10 or less carbon atoms. p represents an integer of 1 to 3.

  Examples of the monomer (2) having a sulfonamide group include a polymer having, as a main component, a minimum structural unit derived from a compound having a sulfonamide group. Examples of the compound as described above include compounds having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated bond groups in the molecule. Among these, low molecular weight compounds having an acryloyl group, an allyl group, or a vinyloxy group, and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in the molecule are preferable. For example, they are represented by the following formulas (i) to (v). Compounds.

In formulas (i) to (v), x ¹ and x ² each independently represent —O— or —NR ⁷ . R ¹ and R ⁴ each independently represents a hydrogen atom or —CH ₃ . R ² , R ⁵ , R ⁹ , R ¹² and R ¹⁶ each independently represent a C 1-12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a substituent. R ³ , R ⁷ and R ¹³ each independently represent a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. R ⁶ and R ¹⁷ each independently represents a C 1-12 alkyl group, cycloalkyl group, aryl group or aralkyl group which may have a substituent. R ⁸ , R ¹⁰ and R ¹⁴ each independently represent a hydrogen atom or —CH ₃ . R ¹¹ and R ¹⁵ each independently represent a C 1-12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a single bond or a substituent. Y ¹ and Y ² each independently represent a single bond or CO.

  Examples of the monomer (3) having an active imide group include a minimum structural unit derived from a compound having an active imide group. Examples of the structural unit as described above include a structural unit having at least one active imide group represented by the following structural formula and one or more polymerizable unsaturated groups.

  Examples of the monomer (4) having a carboxylic acid group include a minimum unit derived from a compound having at least one carboxylic acid group and at least one polymerizable unsaturated group in the molecule.

  Examples of the monomer (5) having a sulfonic acid group include a minimum unit derived from a compound having one or more sulfonic acid groups and polymerizable unsaturated groups in the molecule.

  Examples of the monomer (6) having a phosphate group include a minimum unit derived from a compound having at least one phosphate group and at least one polymerizable unsaturated group in the molecule.

The specific copolymer does not need to contain only one type of monomer having an acid group selected from the group consisting of the above (1) to (6), and two or more types of monomers having the same acid group are introduced. Two or more monomers having different acid groups may be introduced.
In addition, the amount of the acid group introduced into the specific copolymer is not particularly limited as long as the specific copolymer can be dissolved in an alkaline developer having a pH of 10 to 13.

  Particularly preferred as the monomer c is a monomer represented by the following formula (I).

In formula (I), R ¹ is a hydrogen atom or a methyl group, and is preferably a methyl group. The linking group represented by R ² in formula (I) is a linking group having 2 to 30 carbon atoms excluding the substituent, and specifically includes 2 such as alkylene, substituted alkylene, arylene, and substituted arylene. And a group having a structure in which a plurality of these groups are linked by an amide bond or an ester bond. For example, a preferred example of the linking group having a chain structure includes a structure in which alkylenes such as ethylene and propylene are linked through an ester bond.

The linking group represented by R ² is more preferably an (n + 1) -valent hydrocarbon group having an aliphatic cyclic structure having 3 to 30 carbon atoms. Specific examples include compounds having an aliphatic cyclic structure such as cyclopropane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, cyclohexyl, dicyclohexyl, norbornane. In addition, (n + 1) -valent hydrocarbons are similarly exemplified by removing (n + 1) hydrogen atoms on any carbon atom constituting a compound having an aliphatic chain structure having 5 to 20 atoms. Can do.

Any carbon atom of the compound constituting the aliphatic cyclic and chain structure may be substituted with a heteroatom selected from the group consisting of a nitrogen atom, an oxygen atom, or a sulfur atom. Two or more places may be substituted, and when two or more places are substituted, they may be substituted by different heteroatoms.
Examples of the substituent that can be introduced into the linking group represented by R ² include monovalent nonmetallic atomic groups other than hydrogen, such as halogen atoms (—F, —Br, —Cl, —I), hydroxyl groups. And a group, an alkoxy group, an aryloxy group, a mercapto group, an aryl group, an alkenyl group, an alkynyl group, and the like.

When A in Formula (1) is NR ₃ —, R represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by R include an alkyl group, an aryl group, an alkenyl group, and an alkynyl group.
Specific examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isopropyl, isobutyl, sec-butyl, tert -C1-C1 such as butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-norbornyl group Examples include up to 10 linear, branched, or cyclic alkyl groups.

In formula (I), A is preferably an oxygen atom or —NH— because synthesis of the monomer represented by formula (I) is facilitated.
In the formula (I), n is an integer of 1 to 5, and 1 is preferable from the viewpoint of good inking properties. The acid group in the specific copolymer is preferably 0.2 to 10.0 mmol / g, more preferably 0.3 to 5.0 mmol / g per molecule of the specific copolymer. More preferably, it is 4 to 3.0 mmol / g.

In addition to monomer a, monomer b, and monomer c, other monomers may be used in combination with the specific copolymer to the extent that the effect of the present invention is not impaired, for the purpose of improving coatability. .
Here, examples of the monomer used in combination include known monomers such as acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, vinyl esters, styrenes, acrylonitrile, maleic anhydride, maleic imide, and the like. The structural unit derived from is mentioned.

  Examples of the acrylic esters include methyl acrylate, ethyl acrylate, (n- or i-) propyl acrylate, (n-, i-, sec- or tert-) butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, Dodecyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 5-hydroxypentyl acrylate, cyclohexyl acrylate, allyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, glycidyl acrylate, benzyl acrylate, methoxybenzyl Acrylate, chlorobenzyl acrylate, 2- (p-hydroxyphenyl) ethyl acrylate Furfuryl acrylate, tetrahydrofurfuryl acrylate, phenyl acrylate, chlorophenyl acrylate, sulfamoylphenyl acrylate and the like.

  Examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, (n- or i-) propyl methacrylate, (n-, i-, sec- or tert-) butyl methacrylate, amyl methacrylate, 2-ethylhexyl methacrylate, and dodecyl. Methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 5-hydroxypentyl methacrylate, cyclohexyl methacrylate, allyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, glycidyl methacrylate, methoxybenzyl methacrylate, chlorobenzyl Methacrylate, 2- (p-hydroxyphenyl) ethyl Methacrylate furfuryl methacrylate, tetrahydrofurfuryl methacrylate, phenyl methacrylate, chlorophenyl methacrylate, sulfamoylphenyl methacrylate and the like.

  Examples of the acrylamides include acrylamide, N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-butylacrylamide, N-benzylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, and N-tolylacrylamide. N- (p-hydroxyphenyl) acrylamide, N- (sulfamoylphenyl) acrylamide, N- (phenylsulfonyl) acrylamide, N- (tolylsulfonyl) acrylamide, N, N-dimethylacrylamide, N-methyl-N- Examples include phenylacrylamide, N-hydroxyethyl-N-methylacrylamide, and the like.

  Examples of the methacrylamides include methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, N-butylmethacrylamide, N-benzylmethacrylamide, N-hydroxyethylmethacrylamide, N -Phenylmethacrylamide, N-tolylmethacrylamide, N- (p-hydroxyphenyl) methacrylamide, N- (sulfamoylphenyl) methacrylamide, N- (phenylsulfonyl) methacrylamide, N- (tolylsulfonyl) methacrylamide N, N-dimethylmethacrylamide, N-methyl-N-phenylmethacrylamide, N-hydroxyethyl-N-methylmethacrylamide and the like.

  Examples of the vinyl esters include vinyl acetate, vinyl butyrate, vinyl benzoate, and the like.

  Examples of the styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, propyl styrene, cyclohexyl styrene, chloromethyl styrene, trifluoromethyl styrene, ethoxymethyl styrene, acetoxymethyl styrene, methoxy styrene, and dimethoxy styrene. Chlorostyrene, dichlorostyrene, bromostyrene, iodostyrene, fluorostyrene, carboxystyrene and the like.

  Among the monomers used in combination as described above, it is preferable to use acrylic acid esters, methacrylic acid esters, vinyl esters, styrenes and acrylonitriles having 20 or less carbon atoms.

The average molecular weight of the specific copolymer is appropriately determined from the viewpoints of inking properties and developability. Usually, when the average molecular weight is high, the inking property is improved but the developing property tends to deteriorate. When the average molecular weight is low, the developing property is good but the inking property tends to be deteriorated.
The average molecular weight is preferably from 1,000 to 1,000,000, more preferably from 2,000 to 500,000, from the viewpoint of the balance between the effect of improving the coating properties and the inking property, the developability, the handling property, the solvent solubility, and the uniformity during coating. , 3000 to 300,000 are more preferable.
The specific copolymer may be linear, branched or have a block structure.

  When the specific copolymer described above is used in the image recording layer, the specific copolymer may be used alone, or other high functional groups having a fluorine-based substituent outside the scope of the present invention. One or more kinds of molecular compounds may be used in combination and used as a mixture. When used as a mixture, the content of the other polymer compound having a fluorine-based substituent is preferably 1 to 80% by mass, and 1 to 70% by mass with respect to the total weight of the specific copolymer. Is more preferable, and it is further more preferable that it is 1-60 mass%. As the other polymer compound having a fluorine-based substituent, a commercially available one can be used without limitation, and specifically, a fluorine-based surfactant widely used in the field is preferably used.

  The structures of other polymer compounds (P-1 to P-51) that can be used in combination with the specific copolymer are exemplified below together with their weight average molecular weights, but the other polymer compounds are limited to these. is not.

Further, the thermal positive type image recording layer is not limited to a single layer but may have a two-layer structure.
As an image recording layer having a two-layer structure (multilayer image recording layer), a lower layer (hereinafter referred to as “A layer”) having excellent printing durability and solvent resistance is provided on the side close to the support, and a positive layer is provided thereon. A type provided with a layer having excellent image formability (hereinafter referred to as “B layer”) is preferable. This type has high sensitivity and can realize a wide development latitude. The B layer generally contains a photothermal conversion substance. Preferred examples of the photothermal conversion substance include the dyes described above.

As the resin used in the A layer, a polymer having a monomer having a sulfonamide group, an active imino group, a phenolic hydroxy group or the like as a copolymerization component is preferably used because it has excellent printing durability and solvent resistance. . As the resin used for the B layer, an alkaline aqueous solution-soluble resin having a phenolic hydroxy group is preferably exemplified.
In addition to the resin, the composition used for the A layer and the B layer can contain various additives as necessary. Specifically, various additives as described in JP-A-2002-3233769, [0062] to [0085] are preferably used. Further, the additives described in [0053] to [0060] of JP-A-2001-305722 described above are also preferably used.
About each component which comprises A layer and B layer, and its content, it is preferable to make it describe in Unexamined-Japanese-Patent No. 11-218914.

<Others>
As a method for producing a thermal positive type image recording layer and a plate making method, methods described in detail in JP-A No. 2001-305722 can be used.

<Thermal negative type>
The thermal negative photosensitive composition contains a curable compound and a photothermal conversion substance. The thermal negative type image recording layer is a negative photosensitive layer in which a portion irradiated with light such as an infrared laser is cured to form an image portion.
<Polymerized layer>
As one of the thermal negative type image recording layers, a polymerization type image recording layer (polymerization layer) is preferably exemplified. The polymerization layer contains a photothermal conversion substance, a radical generator, a radical polymerizable compound that is a curable compound, and a binder polymer. In the polymerization layer, infrared light absorbed by the photothermal conversion substance is converted into heat, the radical generator is decomposed by this heat to generate radicals, and the radical polymerizable compound is polymerized in a chain by the generated radicals and cured. .

As a photothermal conversion substance, the photothermal conversion substance used for the thermal positive type mentioned above is mentioned, for example. Specific examples of particularly preferred cyanine dyes include those described in JP-A-2001-133969, [0017] to [0019].
Preferable examples of the radical generator include onium salts. In particular, onium salts described in JP-A-2001-133969, [0030] to [0033] are preferable.
Examples of the radically polymerizable compound include compounds having at least one terminal ethylenically unsaturated bond, preferably two or more.
As the binder polymer, a linear organic polymer is preferably exemplified. Preferable examples include linear organic polymers that are soluble or swellable in water or weak alkaline water. Among them, a (meth) acrylic resin having an unsaturated group such as an allyl group or an acryloyl group or a benzyl group and a carboxy group in the side chain is preferable in that it has an excellent balance of film strength, sensitivity, and developability. .
As the radical polymerizable compound and the binder polymer, those described in detail in [0036] to [0060] of JP-A No. 2001-133969 can be used.

  The additive described in [0061] to [0068] of JP-A No. 2001-133969 is contained in the thermal negative photosensitive composition (for example, a surfactant for improving coatability). Is preferred.

  As a method for producing the polymerization layer and a plate making method, methods described in detail in JP-A No. 2001-133969 can be used.

<Acid cross-linked layer>
Further, as one of the thermal negative type image recording layers, an acid cross-linked image recording layer (acid cross-linked layer) is also preferably exemplified. The acid crosslinking layer comprises a photothermal conversion substance, a thermal acid generator, a compound that crosslinks with an acid that is a curable compound (crosslinking agent), and an alkali-soluble polymer compound that can react with the crosslinking agent in the presence of an acid. contains. In the acid cross-linking layer, infrared light absorbed by the light-to-heat conversion substance is converted into heat, and the thermal acid generator is decomposed by this heat to generate an acid, and the generated acid reacts with the cross-linking agent and the alkali-soluble polymer compound. And harden.

Examples of the photothermal conversion substance include the same substances as those used for the polymerization layer.
Examples of the thermal acid generator include thermal decomposition compounds such as photoinitiators for photopolymerization, photochromic agents for dyes, and acid generators used in microresists.
Examples of the crosslinking agent include an aromatic compound substituted with a hydroxymethyl group or an alkoxymethyl group; a compound having an N-hydroxymethyl group, an N-alkoxymethyl group or an N-acyloxymethyl group; and an epoxy compound.
Examples of the alkali-soluble polymer compound include a novolak resin and a polymer having a hydroxyaryl group in the side chain.

<Photopolymer type>
The photopolymerization type photosensitive composition contains an addition polymerizable compound, a photopolymerization initiator, and a polymer binder.
As the addition polymerizable compound, an ethylenically unsaturated bond-containing compound capable of addition polymerization is preferably exemplified. The ethylenically unsaturated bond-containing compound is a compound having a terminal ethylenically unsaturated bond. Specifically, for example, it has a chemical form such as a monomer, a prepolymer, and a mixture thereof. Examples of monomers include esters of unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, maleic acid) and aliphatic polyhydric alcohol compounds, amides of unsaturated carboxylic acids and aliphatic polyvalent amine compounds. Is mentioned.
Moreover, as an addition polymerizable compound, a urethane type addition polymerizable compound is also preferably exemplified.

As the photopolymerization initiator, various photopolymerization initiators or a combination system (photoinitiation system) of two or more photopolymerization initiators can be appropriately selected depending on the wavelength of the light source to be used. For example, the initiation system described in JP-A-2001-22079, [0021] to [0023] is preferable.
The polymer binder not only functions as a film forming agent for the photopolymerization type photosensitive composition, but is soluble or swellable in alkaline water because the image recording layer needs to be dissolved in an alkaline developer. An organic high molecular polymer is used. As such an organic polymer, those described in JP-A-2001-22079, [0036] to [0063] are preferably exemplified.

  In the photopolymer type photopolymerization type photosensitive composition, additives described in JP-A-2001-22079, [0079] to [0088] (for example, a surfactant for improving coatability) , Colorants, plasticizers, thermal polymerization inhibitors).

  Further, it is preferable to provide an oxygen-blocking protective layer on the photopolymer type image recording layer in order to prevent the action of inhibiting the polymerization of oxygen. Examples of the polymer contained in the oxygen barrier protective layer include polyvinyl alcohol and copolymers thereof.

<Conventional negative type>
The conventional negative-type photosensitive composition contains a diazo resin or a photocrosslinking resin. Among these, a photosensitive composition containing a diazo resin and an alkali-soluble or swellable polymer compound (binder) is preferable.
Examples of the diazo resin include condensates of aromatic diazonium salts and active carbonyl group-containing compounds such as formaldehyde; condensates of p-diazophenylamines and formaldehyde with hexafluorophosphate or tetrafluoroborate. Organic solvent-soluble diazo resin inorganic salts which are reaction products of In particular, a high molecular weight diazo compound containing 20 mol% or more of a hexamer described in JP-A-59-78340 is preferable.
Examples of the binder include a copolymer containing acrylic acid, methacrylic acid, crotonic acid, or maleic acid as an essential component. Specifically, a multi-component copolymer of monomers such as 2-hydroxyethyl (meth) acrylate, (meth) acrylonitrile, (meth) acrylic acid as described in JP-A-50-118802, Examples thereof include multi-component copolymers composed of alkyl acrylate, (meth) acrylonitrile and unsaturated carboxylic acid as described in JP-A-56-4144.

  The conventional negative type photosensitive composition has, as additives, the bake-out agent, dye, and flexibility and abrasion resistance described in JP-A-7-281425, [0014] to [0015]. It is preferable to contain a plasticizer for imparting, a compound such as a development accelerator, and a surfactant for improving coatability.

<Conventional positive type>
The conventional positive-type photosensitive composition contains a quinonediazide compound. Among these, a photosensitive composition containing an o-quinonediazide compound and an alkali-soluble polymer compound is preferable.
Examples of the o-quinonediazide compound include esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and phenol-formaldehyde resin or cresol-formaldehyde resin, described in US Pat. No. 3,635,709. And esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and pyrogallol-acetone resin.
Examples of the alkali-soluble polymer compound include phenol-formaldehyde resin, cresol-formaldehyde resin, phenol-cresol-formaldehyde co-condensation resin, polyhydroxystyrene, N- (4-hydroxyphenyl) methacrylamide copolymer, A carboxy group-containing polymer described in JP-A-7-36184, an acrylic resin containing a phenolic hydroxy group as described in JP-A-51-34711, and described in JP-A-2-866 Examples thereof include acrylic resins having a sulfonamide group and urethane resins.

  Conventional positive type photosensitive compositions include compounds such as sensitivity modifiers, printing agents, dyes and the like described in JP-A-7-92660, [0024] to [0027] as additives. It is preferable to contain a surfactant for improving the coating property as described in [0031] of Kaihei 7-92660.

<Non-treatment type>
Examples of the non-processing type photosensitive composition include a thermoplastic fine particle polymer type, a microcapsule type, and a sulfonic acid-generating polymer-containing type. These are all heat-sensitive types containing a photothermal conversion substance. The photothermal conversion substance is preferably the same dye as that used in the above-described thermal positive type.

The thermoplastic fine particle polymer type photosensitive composition is obtained by dispersing a hydrophobic and heat-meltable fine particle polymer in a hydrophilic polymer matrix. In the image recording layer of the thermoplastic fine particle polymer type, the hydrophobic fine particle polymer is melted by heat generated by exposure and is fused to form a hydrophobic region, that is, an image portion.
As the fine particle polymer, those in which fine particles melt and coalesce with heat are preferable, and those having a hydrophilic surface and capable of being dispersed in a hydrophilic component such as dampening water are more preferable. Specifically, ResearchDisclosureNo. 33303 (January 1992), JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, and JP-A-9-171250, and European Patent Application Publication No. 931,647. Preferred examples thereof include thermoplastic fine particle polymers. Of these, polystyrene and polymethyl methacrylate are preferred. Examples of the fine particle polymer having a hydrophilic surface include those in which the polymer itself is hydrophilic; those in which a hydrophilic compound such as polyvinyl alcohol and polyethylene glycol is adsorbed on the surface of the fine particle polymer to make the surface hydrophilic.
The fine particle polymer preferably has a reactive functional group.

  As a microcapsule type photosensitive composition, a compound having a heat-reactive functional group as described in JP-A No. 2000-118160 or JP-A No. 2001-277740 is included. A microcapsule type is preferable.

  Examples of the sulfonic acid generating polymer used in the sulfonic acid generating polymer-containing photosensitive composition include sulfonic acid ester groups, disulfone groups, and sec- or tert-sulfonamides described in JP-A No. 10-282672. Examples thereof include polymers having a group in the side chain.

  By incorporating a hydrophilic resin into the unprocessed photosensitive composition, not only on-press developability is improved, but also the film strength of the photosensitive layer itself is improved. Examples of the hydrophilic resin include those having a hydrophilic group such as hydroxy group, carboxy group, hydroxyethyl group, hydroxypropyl group, amino group, aminoethyl group, aminopropyl group, carboxymethyl group, and hydrophilic sol-gel conversion system. A binder resin is preferred.

  The unprocessed type image recording layer does not require a special development step and can be developed on a printing press. As a method for producing an unprocessed image recording layer and a plate-making printing method, methods described in detail in JP-A No. 2002-178655 can be used.

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

Moreover, you may add a water-soluble thing among the photothermal conversion agents mentioned above to an overcoat layer. Furthermore, for the purpose of ensuring the uniformity of coating, a nonionic surfactant such as polyoxyethylene nonylphenyl ether or polyoxyethylene dodecyl ether can be added to the overcoat layer in the case of aqueous solution coating. .
The dry coating amount of the overcoat layer is preferably 0.1 to 2.0 g / m ² . Within this range, the on-press developability is not impaired, and the surface of the heat-sensitive layer can be satisfactorily prevented from being contaminated with lipophilic substances such as fingerprints.

[Manufacture of lithographic printing plates]
The lithographic printing plate precursor using the lithographic printing plate support obtained by the present invention is made into a lithographic printing plate by various treatment methods according to the image recording layer.
Examples of the active light source used for image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, and a chemical lamp. Examples of the laser beam include helium-neon laser (He-Ne laser), argon laser, krypton laser, helium-cadmium laser, KrF excimer laser, semiconductor laser, YAG laser, and YAG-SHG laser.

After the above exposure, if the image recording layer is one of a thermal positive type, a thermal negative type, a conventional negative type, a conventional positive type, and a photopolymer type, it is exposed and then developed using a developer to obtain a lithographic printing plate. It is preferable to obtain.
The developer is preferably an alkaline developer, and more preferably an alkaline aqueous solution substantially free of an organic solvent.
Moreover, the developing solution which does not contain alkali metal silicate substantially is also preferable. As a method of developing using a developer substantially not containing an alkali metal silicate, a method described in detail in JP-A No. 11-109637 can be used.
A developer containing an alkali metal silicate can also be used.

When the image recording layer is an unprocessed type, the lithographic printing plate precursor according to the present invention is mounted on a printing machine without further processing after image exposure and is usually used with ink and / or fountain solution. You can print with the procedure. Further, as described in Japanese Patent No. 2938398, after being mounted on a printing machine cylinder, it is exposed with a laser mounted on the printing machine, and then ink and / or fountain solution is applied to perform on-machine development. It is also possible to do. In these cases, since the heat-sensitive layer is removed by ink and / or fountain solution on the printing press, there is no need for a separate development step, and there is no need to stop the printing press for printing after development. Printing can be continued as soon as development is completed.
Even in the case of having an untreated type heat-sensitive layer, it can be used for printing after developing with water or an appropriate aqueous solution as a developer.

1. Preparation of lithographic printing plate precursor (Example 1)
<Preparation of aluminum plate>
Si: 0.08 mass%, Fe: 0.30 mass%, Cu: 0.035 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Ti: 0.02 mass% The remainder was made of aluminum and an inevitable impurity aluminum alloy to a thickness of 0.24 mm to obtain a JIS 1050 aluminum plate. After making this aluminum plate width 1030mm, it used for the roughening process shown below.
The average crystal grain size of the obtained aluminum plate was 50 μm in the minor axis and 300 μm in the major axis.

<Roughening treatment>
The roughening treatment was performed by continuously performing the following treatments (a) to (i). After each treatment and washing with water, the liquid was removed with a nip roller.

(A) Mechanical surface roughening treatment Using an apparatus as shown in FIG. 1, a suspension of abrasive (pumice) having a specific gravity of 1.12 and water is supplied as a polishing slurry to the surface of the aluminum plate. However, a mechanical surface roughening treatment was performed with a rotating roller-like nylon brush. In FIG. 1, 1 is an aluminum plate, 2 and 4 are roller brushes, 3 is a polishing slurry, and 5, 6, 7 and 8 are support rollers. The average particle size of the abrasive was 8 μm, and the maximum particle size was 50 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate was subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 26% by mass, an aluminum ion concentration of 6.5% by mass, and a temperature of 72 ° C. to dissolve the aluminum plate by 7 g / m ² . Then, water washing by spraying was performed.

(C) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used in this treatment was a waste liquid from the step of performing an electrochemical surface roughening treatment using alternating current in an aqueous nitric acid solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 35 ° C. The AC power supply waveform is the waveform shown in FIG. 2, the time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, the trapezoidal rectangular wave AC is used, with the carbon electrode as the counter electrode An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell used was the one shown in FIG. In FIG. 3, 11 is an aluminum plate, 12 is a radial drum roller, 13a and 13b are main poles, 14 is an electrolytic treatment liquid, 15 is an electrolytic solution supply port, and 16 is a slit. , 17 is an electrolyte passage, 18 is an auxiliary anode, 19a and 19b are thyristors, 20 is an AC power source, 40 and 41 are main electrolytic cells, and 50 and 51 are auxiliary anode cells. .
The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 110 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Then, water washing by spraying was performed.

(E) Alkali etching treatment An aluminum plate was subjected to an etching treatment by spraying at 73 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass%, and the aluminum plate was dissolved by 5.5 g / m ² . Removes the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening treatment was performed using the alternating current of the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(F) Desmut treatment Desmut treatment by spraying was performed with a 15% by weight aqueous solution of sulfuric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water by spraying.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 6.2 g / L aqueous solution (containing 4.5 g / L of aluminum ions) at a temperature of 35 ° C. Using a sinusoidal alternating current, an electrochemical roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The electrolytic cell used was the one shown in FIG.
The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 60 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. Then, water washing by spraying was performed.

(H) Alkali etching treatment The aluminum plate was subjected to an etching treatment at 48 ° C. using an aqueous solution having a caustic soda concentration of 5% by mass and an aluminum ion concentration of 6.5% by mass to dissolve the aluminum plate by 0.20 g / m ² . Removes the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening treatment was performed using the alternating current of the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(I) Desmutting treatment A desmutting treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(J) Anodizing treatment Next, the anodizing apparatus having the structure shown in FIG. 5 (the lengths of the first and second electrolysis parts are 6 m each, the lengths of the first and second feeding parts are 3 m each, the first and first Anodization treatment was performed using 2 feed electrodes each having a length of 2.4 m). As the electrolytic solution supplied to the first and second electrolytic units 63a and 63b, sulfuric acid was used. All electrolytes had a sulfuric acid concentration of 170 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 47 ° C. Then, water washing by spraying was performed.

In this anodizing device, currents from the power supplies 67a and 67b flow to the first power supply electrode 65a provided in the first power supply section 62a, flow to the aluminum plate 11 through the electrolytic solution, and in the first electrolysis section 63a. An oxide film is generated on the surface of the aluminum plate 11, passes through the electrolytic electrodes 66a and 66b provided in the first electrolysis unit 63a, and returns to the power sources 67a and 67b.
On the other hand, the current from the power supplies 67c and 67d flows to the second power supply electrode 65b provided in the second power supply part 62b, dissolves the electrolyte, flows to the aluminum plate, and the surface of the aluminum plate 11 by the second electrolysis part 63b. Then, the oxide film is generated, passes through the electrolytic electrodes 66c and 66d provided in the second electrolysis unit 63b, and returns to the power sources 67c and 67d.

The amount of electricity fed from the power sources 67a and 67b to the first feeding unit 62a is equal to the amount of electricity fed from the power sources 67c and 67d to the second feeding unit 62b, and the first electrolysis unit 63a and the second electrolysis unit The current density of 63b was 30 mA / dm ² in all cases. The amount of the oxide film generated in the first electrolysis unit 63a was 1.35 g / m ² . In the 2nd electric power feeding part 62b, it will feed through the oxide film surface produced | generated by the 1st electrolysis part 63a, and the final oxide film amount was 2.4 g / m < ² >. In FIG. 5, 64a and 64b are nip rollers.

(K) Alkali metal silicate treatment (silicate treatment)
The aluminum plate after the anodizing treatment was immersed in a treatment tank of an aqueous sodium silicate solution to perform alkali metal silicate treatment (silicate treatment). The aqueous sodium silicate solution used and the immersion time were as shown in “Condition A” in Table 1. Thereafter, washing with spray using well water was performed to obtain a lithographic printing plate support.

<Formation of intermediate layer>
On each lithographic printing plate support obtained above, the ratio of the acid group component shown in the following formula (13) and the onium group component shown in the following formula (14) to No. 1 in Table 2 in 100 g of methanol. A coating solution in which 0.3 g of the polymer compound polymerized in (1) was dispersed was applied and dried at 80 ° C. for 15 seconds to form an intermediate layer. The coating amount of the intermediate layer was 15 mg / m ² .

<Formation of image recording layer>
Next, an image recording layer coating solution A1 having the following composition was coated on the intermediate layer with a wire bar so as to be 0.85 g / m ² after drying, and dried at 140 ° C. for 50 seconds.
After that, the image recording layer coating liquid B1 having the following composition was applied with a wire bar so as to be 0.25 g / m ² after drying, and dried at 140 ° C. for 1 minute to form a multilayer thermal positive type image recording layer. And a lithographic printing plate precursor was obtained.

<Coating liquid A1 for image recording layer>
N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate copolymer (molar ratio 36/34/30, weight average molecular weight 50,000, acid value 2.65) 1.920 g
-M, p-cresol novolak (m-cresol novolak / p-cresol novolak = 6/4, weight average molecular weight 4000) 0.213 g
-Cyanine dye A represented by the following formula 0.032 g
・ 0.008 g of p-toluenesulfonic acid
・ Tetrahydrophthalic anhydride 0.190g
・ Bis-p-hydroxyphenylsulfone 0.126 g
・ 2-methoxy-4- (N-phenylamino) benzenediazonium ・ hexafluorophosphate 0.032 g
-0.078 g of a dye in which the counter anion of Victoria Pure Blue BO is a 1-naphthalenesulfonic acid anion
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.020g
・ Γ-butyrolactone 13.180 g
・ Methyl ethyl ketone 25.410g
1-methoxy-2-propanol 12.970 g

<Image Recording Layer Coating Liquid B1>
-Phenol / m, p-cresol novolak (phenol / m-cresol novolak / p-cresol novolak = 5/3/2, weight average molecular weight 4000) 0.274 g
-0.029 g of cyanine dye A represented by the above formula
-Structural polymer B / methyl ethyl ketone 30% solution represented by the following formula (Structural polymer B / methyl ethyl ketone 30% solution) 0.140 g
-Quaternary ammonium salt C shown by the following formula 0.004 g
・ Sulfonium salt D represented by the following formula: 0.065 g
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.004g
-0.020 g of fluorosurfactant E represented by the following formula
・ Methyl ethyl ketone 10.39g
・ 1-methoxy-2-propanol 20.98g

(Example 2)
In Example 2, a lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the sodium silicate aqueous solution and the immersion time used in (k) were changed to the conditions shown in “Condition B” in Table 1. .

(Example 3)
In Example 3, a lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the sodium silicate aqueous solution and the immersion time used in (k) were changed to the conditions shown in “Condition C” in Table 1. .

(Example 4)
In Example 4, a lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the sodium silicate aqueous solution and the immersion time used in (k) were changed to the conditions shown in “Condition D” in Table 1. did.

(Example 5)
In Example 5, a lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the sodium silicate aqueous solution and the immersion time used in (k) were changed to the conditions shown in “Condition E” in Table 1. did.

(Example 6)
In Example 6, 0.3 g of a polymer compound obtained by polymerizing an acid group component represented by the above formula (13) and an onium group component represented by the above formula (14) at a ratio indicated by No2 in Table 2 was dispersed. A lithographic printing plate precursor was prepared in the same manner as in Example 2 except that the intermediate layer was prepared using the applied coating solution.

(Example 7)
In Example 7, 0.3 g of a polymer compound obtained by polymerizing an acid group component represented by the above formula (13) and an onium group component represented by the above formula (14) at a ratio indicated by No. 3 in Table 2 was dispersed. A lithographic printing plate precursor was prepared in the same manner as in Example 2 except that the intermediate layer was prepared using the applied coating solution.

(Example 8)
In Example 8, an aluminum plate was produced in the same manner as in Example 1 except that an aluminum alloy of Cu: 0.025% by mass was used.
Further, the amount of electricity in (d) above is 197 C / dm ^{2 in} terms of the total amount of electricity when the aluminum plate is an anode, and the amount of dissolution of the aluminum plate is 3.0 g / m ² by carrying out (e) at 50 ° C. A lithographic printing plate precursor was prepared in the same manner as in Example 2 except that the hydrochloric acid concentration in the above (g) was 5.0 g / L.

Example 9
In Example 9, a lithographic printing plate precursor was prepared in the same manner as in Example 8, except that the above (e) was performed at 40 ° C. and the amount of dissolution of the aluminum plate was 10.0 g / m ² .

(Example 10)
In Example 10, a lithographic printing plate precursor was produced in the same manner as in Example 8, except that (g), (h), and (i) were not performed.

(Example 11)
In Example 11, an aluminum plate was produced in the same manner as in Example 1, except that an aluminum alloy of Cu: 0.005% by mass was used.
Further, the above (e) is performed at 32 ° C. and the dissolution amount of the aluminum plate is 0.25 g / m ^{2. The} above (h) is performed at 32 ° C. and the dissolution amount of the aluminum plate is 0.10 g / m ² . Except for the above, a lithographic printing plate precursor was prepared in the same manner as in Example 8.

(Example 12)
In Example 12, a lithographic printing plate precursor was produced in the same manner as in Example 10 except that the above (e) was carried out at 45 ° C. and the dissolution amount of the aluminum plate was 2.0 g / m ² .

(Comparative Example 1)
In Comparative Example 1, a lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the sodium silicate aqueous solution and the immersion time used in (k) were changed to the conditions shown in “Condition F” in Table 1. .

(Comparative Example 2)
In Comparative Example 2, a lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the sodium silicate aqueous solution and the immersion time used in (k) were changed to the conditions shown in “Condition G” in Table 1. .

(Comparative Example 3)
In Comparative Example 3, a lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the sodium silicate aqueous solution and the immersion time used in (k) were changed to the conditions shown in “Condition H” in Table 1. .

(Comparative Example 4)
In Comparative Example 4, a lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the sodium silicate aqueous solution and the immersion time used in (k) were changed to the conditions shown in “Condition I” in Table 1. .

(Comparative Example 5)
In Comparative Example 5, a lithographic printing plate precursor was prepared in the same manner as in Example 2 except that no intermediate layer was formed.

(Comparative Example 6)
In Comparative Example 6, 0.3 g of a polymer compound obtained by polymerizing the acid group component represented by the above formula (13) and the onium group component represented by the above formula (14) at a ratio indicated by No 4 in Table 2 was dispersed. A lithographic printing plate precursor was prepared in the same manner as in Example 2 except that the intermediate layer was prepared using the applied coating solution.

(Comparative Example 7)
In Comparative Example 7, 0.3 g of a polymer compound obtained by polymerizing the acid group component represented by the above formula (13) and the onium group component represented by the above formula (14) at a ratio indicated by No5 in Table 2 was dispersed. A lithographic printing plate precursor was prepared in the same manner as in Example 2 except that the intermediate layer was prepared using the applied coating solution.

2. Calculation of surface area ratio ΔS and steepness a45 of lithographic printing plate support The surface area ratio ΔS and steepness a45 were calculated as follows for the lithographic printing plate support obtained by performing the treatment of (k) above. .

(1) Measurement of surface shape with electron force microscope First, the surface shape was measured with an atomic force microscope (SP13700, manufactured by Seiko Denshi Kogyo Co., Ltd.) to obtain three-dimensional data (f (x, y)). A specific procedure will be described below.
The planographic printing plate support is cut to a size of 1 cm square, set on a horizontal sample stage on a piezo scanner, and the cantilever is approached to the sample surface. Scanning was performed, and the unevenness of the sample was captured by the displacement of the piezoelectric element in the Z direction. A piezo scanner that can scan 150 μm in the XY direction and 10 μm in the Z direction was used. A cantilever having a resonance frequency of 120 to 150 kHz and a spring constant of 12 to 20 N / m (AC-160TS, manufactured by Olympus Corporation) was used and measured in a DFM mode (Dynamic Force Mode). Further, the reference plane was obtained by correcting the slight inclination of the sample by least-square approximation of the obtained three-dimensional data.
At the time of measurement, the surface of 50 μm □ was measured at 512 × 512 points. The resolution in the XY direction was 1.9 μm, the resolution in the Z direction was 1 nm, and the scan speed was 5 μm / sec.

(2) Calculation of surface area ratio ΔS Next, using the three-dimensional data (f (x, y)) obtained in (1) above, three adjacent points are extracted, and a micro triangle formed by the three points is extracted. The total area was calculated and used as the actual area _Sx . The surface area ratio ΔS was determined by the following formula (1) from the obtained real area S _x and the geometric measurement area S ₀ .

ΔS = [(S _x −S ₀ ) / S ₀ ] × 100 (%) (1)

(3) Calculation of steepness a45 Using the three-dimensional data (f (x, y)) obtained in (1) above, each reference point and two adjacent points in a predetermined direction (for example, right and bottom) The angle formed by the small triangle formed by the three points and the reference plane is calculated for each reference point. The number of reference points whose inclination of the micro triangle is 45 degrees or more is obtained by subtracting the number of all reference points (the number of all data 512 × 512 points and the number of points having no two adjacent points in a predetermined direction). I.e., 511 × 511 points), the area ratio of the portion with the inclination of 45 degrees or more was calculated.

  The calculated surface area ratio ΔS and the steepness a45 were as shown in Table 3.

3. The amount of Si on the surface of the lithographic printing plate support The amount of Si on the surface of the lithographic printing plate support after the alkali metal silicate treatment was measured by a calibration curve method using a fluorescent X-ray analyzer. The results are shown in Table 4.
As a standard sample for preparing a calibration curve, an aqueous solution containing a known amount of silicon atoms was uniformly dropped into an area of 30 mmφ on an aluminum plate and then dried. The conditions for fluorescent X-ray analysis are shown below.

  X-ray fluorescence analyzer: RIX3000 manufactured by Rigaku Corporation, X-ray tube: Rh, measurement spectrum: Si-Kα, tube voltage: 50 kV, tube current: 50 mA, slit: COARSE, spectral crystal: RX4, detector: F -PC, analysis area: 30 mmφ, peak position (2θ): 144.75 deg. , Background (2θ): 140.70 deg. And 146.85 deg. Integration time: 80 seconds / sample

4). Exposure and development of lithographic printing plate precursor The lithographic printing plate precursor obtained above is exposed using a Trend setter manufactured by Creo under the conditions of a beam intensity of 10 W and a drum rotation speed of 150 rpm, and an FM screen (Staccato 20, manufactured by Creo) The test pattern created in step 1 was drawn in an image.
Next, a 1: 8 water diluted solution (conductivity of about 43 mS / cm) of developer DT-2 manufactured by Fuji Photo Film Co., Ltd. was charged as the developer, and finisher FG-1 manufactured by Fuji Photo Film Co., Ltd. was used as the finisher. Using a PS processor LP940H manufactured by Fuji Photo Film Co., Ltd., which was charged with a 1: 1 water dilution solution, the lithographic printing plate precursor after exposure was maintained for 12 seconds while maintaining the developer and finisher liquid temperature at 30 ° C. Development was performed to obtain a lithographic printing plate.

5). Evaluation of lithographic printing plate precursors The printing durability of the lithographic printing plate obtained above, the ease of balancing water and ink (entanglement stain resistance and fleshing resistance), anti-bleeding stain resistance, and erasure stain resistance. Evaluation was made by the following method.

(1) Ease of balancing water and ink The lithographic printing plate obtained above is mounted on a Heidelberg printing press SOR-M, and it is IF102 3% (made by Fuji Photo Film Co., Ltd.) in dampening water. The ink was printed with Varius (N) ink (manufactured by Dainippon Ink & Chemicals, Inc.), and the amount of dampening water was gradually reduced from the standard water scale. The degree of occurrence of entangled dirt in () was visually evaluated. Further, the amount of dampening water was gradually increased from the standard water scale, and the inking property of the image area was evaluated. The results are shown in Table 4. In Table 4, it is indicated as “easy to balance”. In the table, ○ indicates that the inking property is good and no entanglement stain is generated, and x indicates that the inking property is generated but the entanglement stain is generated and the halftone dot is almost completely crushed. .

(2) Printing durability The lithographic printing plate obtained above is mounted on a Lislon printing machine manufactured by Komori Corporation, and printing is performed using Varius (N) ink (manufactured by Dainippon Ink & Chemicals, Inc.) as ink. The printing durability was evaluated based on the number of printed sheets when it was visually confirmed that the density of the solid image of the printed material began to decrease. The results are shown in Table 4.

(3) Anti-stain stain resistance The lithographic printing plate obtained above is mounted on a printing machine SOR-M manufactured by Heidelberg, IF102 3% (manufactured by Fuji Photo Film Co., Ltd.) in fountain solution, and Varius (N ) After printing 5000 sheets using black ink (manufactured by Dainippon Ink & Chemicals, Inc.), the planographic printing plate was removed from the printing press and left for 1 hour. After leaving for 1 hour, the lithographic printing plate was mounted on the printing machine again and printed, and the number of printed sheets at the time when the printed matter was recovered and the normal printed matter was obtained was evaluated. The smaller the number of printed sheets, the better the stain resistance. The results are shown in Table 4.

(4) Erasing stain resistance The unnecessary image portion of the lithographic printing plate obtained above was erased with an erasing solution PR-2 (manufactured by Fuji Photo Film Co., Ltd.) and then washed with water. The erasing time was changed every 10 seconds between 10 seconds and 120 seconds.
Next, the washed lithographic printing plate is mounted on a printing press made by Mitsubishi Heavy Industries, Ltd., IF102 3% (made by Fuji Photo Film Co., Ltd.) in fountain solution, and GEOS (S) Red (Dainippon Ink, Inc.) in ink. 1000 sheets were printed using Chemical Industries, Ltd., and the erasure resistance was visually evaluated. The results are shown in Table 4. The meanings of the symbols in Table 4 are as follows.
○: Unnecessary image portion erase time is 30 seconds or less. Δ: Unnecessary image portion erase time is 40 to 80 seconds.

  As is apparent from Table 4, the lithographic printing plate precursors (Examples 1 to 12) of the present invention are easy to balance water and ink and printing durability when FM screens are used for halftone dots. It is excellent in both resistance to leaving dirt and resistance to erasure.

In contrast, when the pH of the aqueous solution used in the alkali metal silicate treatment is too low (Comparative Example 1), the entanglement stain resistance is poor, and when the pH is too high (Comparative Example 4), water and ink are used. It was inferior in balance.
Further, when the surface Si amount is too small (Comparative Example 2), the entanglement stain resistance and neglected stain resistance are poor, and when the surface Si amount is too large (Comparative Example 3), the printing durability is low. It was inferior.
In the case where no intermediate layer is formed on the surface (Comparative Example 5), the erasure stain resistance, the neglectable stain resistance, and the printing durability are inferior, and the intermediate layer does not contain a component having an onium group. (Comparative Example 6) is inferior in printing durability and erasure stain resistance, and when the intermediate layer does not contain a component having an acid group (Comparative Example 7), it is resistant to erasure stain and stain resistance. And printing durability were inferior.

It is a side view which shows the concept of the process of the brush graining used for the mechanical roughening process in preparation of the support body for lithographic printing plates used for the lithographic printing plate precursor of this invention. It is a graph which shows an example of the alternating waveform current waveform figure used for the electrochemical roughening process in preparation of the support body for lithographic printing plates used for the lithographic printing plate precursor of this invention. It is a side view which shows an example of the radial type cell in the electrochemical roughening process using alternating current in preparation of the support body for lithographic printing plates used for the lithographic printing plate precursor of this invention. It is the schematic of the anodizing apparatus used for the anodizing process in preparation of the support body for lithographic printing plates used for the lithographic printing plate precursor of this invention. It is the schematic of the anodizing apparatus of the two-stage electric power feeding method used for the anodizing process in preparation of the support body for lithographic printing plates used for the lithographic printing plate precursor of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aluminum plate 2, 4 Roller-shaped brush 3 Polishing slurry liquid 5, 6, 7, 8 Support roller 11 Aluminum plate 12 Radial drum roller 13a, 13b Main electrode 14 Electrolytic process liquid 15 Electrolyte supply port 16 Slit 17 Electrolyte path 18 Auxiliary anodes 19a, 19b Thyristors 20 AC power supply 40 Main electrolytic cell 50 Auxiliary anode cell 62a First power supply unit 62b Second power supply unit 63a First electrolysis unit 63b Second power supply unit 64a, 64b Nip roller 65a First power supply electrode 65b Second power supply Electrodes 66a, 66b, 66c, 66d Electrolytic electrodes 67a, 67b, 67c, 67d Power supply 410 Anodizing device 412 Power supply tank 414 Electrolytic treatment tank 416 Aluminum plate 418, 426 Electrolytic solution 420 Power supply electrode 422, 428 Roller 424 Nip roller 430 Electrolytic electrode 32 tank wall 434 DC power supply

Claims (2)

An aluminum plate having a surface Si amount of 3.0 to 15.0 mg / m ² obtained by treatment using an aqueous solution of pH 11.5 to 13.0 containing an alkali metal silicate;
An intermediate layer formed using a polymer material containing a component having an acid group and a component having an onium group on the aluminum plate;
A lithographic printing plate precursor comprising an image recording layer formed on the intermediate layer. 2. The planographic printing plate precursor according to claim 1, wherein the aluminum plate has a surface area ratio ΔS of 10 to 50% and a steepness a45 of 5 to 40%.
However, the surface area ratio ΔS is obtained by measuring the actual area S _x obtained by the approximate three-point method from the three-dimensional data obtained by measuring 512 × 512 points of the surface 50 μm □ using an atomic force microscope, and geometric measurement. The area S ₀ is a value obtained by the following formula (1), and the steepness a45 is an area of a portion having an inclination of 45 ° or more with respect to the actual area S _x (an inclination of 45 ° or more). Rate.
ΔS = (S _x −S ₀ ) / S ₀ × 100 (%) (1)

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