JP2003129300A - Surface-roughening process for aluminum plate and aluminum substrate for lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a substrate for a lithographic printing plate by forming a good rough surface on an aluminum plate using only electrolytic etching. SOLUTION: An etching step wherein the aluminum plate is etched with an alkali, a desmutting step wherein the aluminum plate is desmutted with an acid, a roughening step wherein the aluminum plate is subjected to electrolytic polishing with an electrolyte containing nitric acid and sulfuric acid, a second etching step wherein the aluminum plate is etched with an alkali, a second desmutting step wherein the aluminum plate is desmutted with an acid and an anodic oxidation step wherein the aluminum plate is subjected to anodic oxidation, are performed in this order.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for roughening an aluminum plate. The present invention also relates to an aluminum support for a lithographic printing original plate and a method for producing the same.

[0002]

In printing plates, especially lithographic printing plates, it is common to use an aluminum plate as a support. Aluminum is characterized by being lightweight, inexpensive, low in elongation, highly hydrophilic, and easy to polish. All of these characteristics are advantageous when an aluminum plate is used as a support for a lithographic printing plate. When making a planographic printing plate,
An image composed of a hydrophobic (ink-receptive) image portion and a hydrophilic (fountain solution-receptive) non-image portion is formed. The hydrophobic image area is formed from a layer (usually a photosensitive layer) provided on the aluminum support, and the hydrophilic image area is formed from the exposed hydrophilic surface of the aluminum support. The surface of the aluminum plate is relatively hydrophilic, but if it is left as it is, water retention (fountain solution receptivity) is insufficient. Therefore, in the production of the aluminum support, the surface of the aluminum plate is roughened to carry out a roughening treatment for improving water retention.

In the roughening treatment of an aluminum plate, it is necessary to consider not only the improvement of water retention but also the adhesion to a layer provided thereon, the prevention of stains during printing and the reproducibility of halftone dots. . For the roughening treatment, mechanical treatment (eg, brush polishing method, ball polishing method, wire polishing method), electrochemical treatment (eg, electrolytic etching method), chemical treatment (eg, chemical etching method), Numerous means have been proposed such as liquid honing, sandblasting and combinations thereof. However, the means that can satisfy the conditions to be considered in addition to the improvement of water retention are brush polishing method, electrolytic etching method, chemical etching method and liquid honing method. It is limited to the polishing method, the electrolytic etching method and the combination thereof.

The brush polishing method is described, for example, in JP-A-6-135175. FIG. 1 is a schematic cross-sectional view of the brush polishing apparatus (the same as FIG. 1 of JP-A-6-135175). The device shown in FIG. 1 uses two types of brushes (2, 4). As shown in FIG. 1, a roll-shaped brush (2, 4) sandwiching an aluminum plate (1).
And two support rolls (5, 6, 7, 8) are arranged respectively. The support rolls (5, 6, 7, 8) are arranged such that the shortest distances between their outer surfaces are smaller than the outer diameters of the roll-shaped brushes (2, 4), respectively, whereby the aluminum plate (1) is formed. Is a roll brush (2, 4)
Is pressurized to. The aluminum plate (1) is conveyed at a constant speed while being pressed between the support rolls (5, 6, 7, 8). Polishing slurry liquid (3)
Are supplied onto the aluminum plate (1), and the surface of the aluminum plate (1) is polished by the rotation of the roll brushes (2, 4).

As the polishing slurry liquid (3), it is usual to use a pumicetone-water suspension. A nylon brush is generally used as the roll brush (2, 4). In the brush polishing method, a large amount of aluminum plates can be continuously processed by using the apparatus shown in FIG. There is also an advantage that a uniform rough surface can be obtained. However, adjustment of the brush polishing device requires skill.
With a brush polishing device, wear of the brush is unavoidable, and it is necessary for a skilled worker to constantly fine-tune the device in response to the wear of the brush. Further, the brush polishing method has a problem that it is difficult to increase the surface roughness.

The electrolytic etching method is described in, for example, Japanese Patent Publication No. 63-16000. FIG. 2 is a schematic sectional view of an electrolytic etching apparatus (Japanese Patent Publication No. Sho 63-1600).
(The same as FIG. 3 of Japanese Patent No. 0). As shown in FIG. 2, the aluminum plate (11) is introduced into the apparatus by the guide roll (12) and wound around the drum roll (13). The aluminum plate (11) transported in the device is
It is transferred to the outside of the device by the guide roll (14). The electrolytic treatment is performed from the electrolytic treatment start point (A ′) to the electrolytic treatment end point (B ′). The electrodes (15, 16) are arranged inside the device so as to face the aluminum plate (11).
The electrode (24) at the electrolytic treatment start portion is a so-called soft start zone, and is electrically insulated from the electrode (15) by an insulator (25) made of an insulating material. The contact feeding roll (17) is in contact with the aluminum plate (11) and is rotationally driven at the same speed as the aluminum plate. The electrolytic solution (18) was mixed with the drum roll (1
3) is supplied from the electrolyte solution supply part (19) arranged immediately below, fills the inside of the device, and the electrolyte solution discharge part (20, 20 ')
Is discharged from the device. The discharged electrolytic solution is forcedly circulated by the pump (22) through the circulation tank (21). As for the output terminals of the alternating waveform power supply (23), one is a contact power supply roll (17) and the other is an electrode (15, 1).
6) and the electrode (24) in the soft start zone, and voltage is applied. Electrodes in soft start zone (2
4) is connected via a resistor (26). Resistor (2
6) controls the current to the electrode (24) in the soft start zone.

A dilute solution of nitric acid or hydrochloric acid (1 to 5%) is usually used as the electrolytic solution (18). The electrolytic etching method can obtain an aluminum plate having a rough surface of a certain quality without requiring special skill. However, the obtained rough surface state (cross-sectional shape) is better in the brush polishing method than in the electrolytic etching method.

Japanese Patent Publication No. 57-16918 proposes to carry out the electrolytic etching method after the brush polishing method. For the combination of the brush polishing method and the electrolytic etching method, the Printing Engineering Handbook (1)
(983) pp. 505-506 "Recently, Fuji Photo Film announced a PS plate with a multi-grained grain structure called multi-grain, which was produced by brush polishing-chemical etching-electrolytic etching-anodizing process. There is. " By combining the brush polishing method and the electrolytic etching method, the problems of both can be solved mutually.
For example, the combined use with the electrolytic etching method alleviates the burden of the brush polishing method and allows a skilled worker to perform the treatment relatively easily without strictly adjusting the brush polishing apparatus. In addition, a better rough surface structure can be obtained by combining them.

FIG. 3 shows a result of measuring a rough surface of an aluminum plate obtained by carrying out a conventional brush polishing method with a stylus meter (printing engineering manual, page 505, FIG. 2.5.12 (1). ) Is the same). FIG. 4 is a result of measuring a rough surface of an aluminum plate obtained by carrying out the conventional electrolytic etching method with a stylus meter (see Printing Engineering Handbook page 505, FIG.
It is the same as (2) in 5.12). FIG. 5 is a result of measuring a rough surface of an aluminum plate obtained by performing a conventional electrolytic etching method after a conventional brush polishing method by a stylus meter (printing engineering manual, page 505, FIG. 2.5. 12 of (3)
Same as). As shown in FIG. 5, by combining the brush polishing method and the electrolytic etching method, a good rough surface which cannot be obtained by the brush polishing method alone (FIG. 3) or the electrolytic etching method alone (FIG. 4) can be formed. it can.

[0010]

By carrying out the electrolytic etching method after the brush polishing method, most of the problems in the prior art have been solved. However, there is one problem that has not been solved sufficiently. That is, this is a problem that requires skill to adjust the brush polishing device. The combined use with the electrolytic etching method reduced the burden of the brush polishing method, but it is still necessary to adjust the brush polishing apparatus.

It is an object of the present invention to form a rough surface on an aluminum plate by the electrolytic etching method alone or by the brush polishing method alone or the combination of the brush polishing method and the electrolytic etching method. It is also an object of the present invention to form a multi-layered grain structure on the surface of an aluminum plate only by the electrolytic etching method. Furthermore, it is an object of the present invention to provide an electrolytic etching method in which the reuse of the electrolytic solution is easy. Furthermore, an object of the present invention is to provide a method for producing an aluminum support for a lithographic printing plate precursor that can be carried out by a skilled technician without rigorously preparing the apparatus.

[0012]

The object of the present invention is to provide a roughening treatment method for an aluminum plate according to the following (1) to (4), an aluminum support for a lithographic printing original plate according to the following (5) and the following (6). It was achieved by the method of manufacturing an aluminum support for a lithographic printing original plate of (10) to (10). (1) A roughening treatment method for an aluminum plate, which comprises immersing an aluminum plate having a smooth surface in an electrolytic solution and roughening the surface by electrolytic polishing, wherein the electrolytic solution contains nitric acid and sulfuric acid. Roughening treatment method for aluminum plate.

(2) The roughening treatment method according to (1), wherein the electrolytic solution contains 5 to 30 g / liter of nitric acid and 0.5 to 10 g / liter of sulfuric acid. (3) The surface-roughening treatment method according to (1), after performing an electrolytic polishing treatment using an electrolytic solution containing nitric acid and sulfuric acid, and further performing a second electrolytic polishing treatment using an electrolytic solution containing nitric acid. (4) The roughening treatment method according to (3), wherein the electrolytic solution used for the second electrolytic polishing treatment contains 0.1 to 30 g / liter of nitric acid.

(5) An aluminum support for a lithographic printing original plate having a multi-layered grain structure formed on the surface only by electrolytic polishing treatment. (6) Etching process for etching aluminum plate with alkali; Desmut process for desmutting aluminum plate with acid; Roughening process for electrolytic polishing aluminum plate with electrolytic solution containing nitric acid and sulfuric acid; Aluminum plate with alkali Second etching step of etching treatment;
A second method of desmutting an aluminum plate with an acid; and a method of manufacturing an aluminum support for a lithographic printing plate precursor, which comprises an anodizing step of anodizing an aluminum plate in this order.

(7) The production method according to (6), wherein nitric acid is used as an acid in the desmut step. (8) For the lithographic printing original plate described in (6), between the surface roughening step and the second etching step, a second surface roughening step of electrolytically polishing an aluminum plate with an electrolytic solution containing nitric acid is performed. Method for manufacturing aluminum support. (9) The production method according to (6), wherein sulfuric acid is used as the acid in the second desmut step. (10) The manufacturing method according to (6), wherein an electrolytic solution containing sulfuric acid is used in the anodizing step. The aluminum plate having a smooth surface means that the surface roughness (Ra) is less than 0.1.

[0016]

As a result of the research conducted by the present inventors, the electrolytic etching method succeeded in forming a rough surface on an aluminum plate similar to the brush polishing method. That is, when a mixed acid of nitric acid and sulfuric acid is used as the electrolytic solution, unlike the conventional electrolytic etching method (using hydrochloric acid or nitric acid as the electrolytic solution), a surface roughness similar to the brush polishing method is obtained on the aluminum plate surface. To be Following the new electrolytic etching method using a mixed acid of nitric acid and sulfuric acid, the conventional electrolytic etching method using nitric acid is carried out, and a rough surface similar to the case where the brush polishing method and the electrolytic etching method are used in combination is applied. It can be formed into a plate. That is, a result equivalent to the combined use of the brush polishing method and the electrolytic etching method, that is, the best result obtained by the conventional technique, that is, the multilayered grain structure can be obtained only by the electrolytic etching method.

As mentioned above, the electrolytic etching method, unlike the brush polishing method, can be carried out without the need for rigorous preparation of the apparatus by a skilled technician. Further, since a mixed acid of nitric acid and sulfuric acid is used in the electrolytic solution, it is not necessary to use pure nitric acid or sulfuric acid, in other words, nitric acid mixed with some sulfuric acid or sulfuric acid mixed with some nitric acid. Available for In the production of an aluminum support for a lithographic printing plate precursor, there are many steps (etching step, desmutting step, anodizing step) using nitric acid or sulfuric acid in addition to the surface roughening treatment, and nitric acid and sulfuric acid are contained in the waste liquid of the processing step. Both are usually included. In the present invention, nitric acid and sulfuric acid contained in the waste liquid can be reused in the electrolytic solution without being separated.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION [Manufacturing Process of Aluminum Support for Lithographic Printing Plate] FIG. 6 shows a method for manufacturing an aluminum support for a lithographic printing plate, in which electrolytic etching is carried out after brush polishing (prior art). It is a flowchart showing. In the conventional technique shown in FIG. 6, the aluminum plate (A
l) is a brush polishing step (Bu), a first etching step (Et1), a first desmutting step (De1), an electrolytic polishing step (El) using an electrolytic solution containing nitric acid, a second etching step (Et2), Second desmut process (De2),
Then, an aluminum support is manufactured by the anodizing step (An). As shown in FIG. 6, it is common to carry out a water washing step (Wa1 to Wa5) before and after each step. Note that AC is an AC power supply and DC is a DC power supply.

FIG. 7 is a flow chart showing the basic aspect of the present invention. In the embodiment shown in FIG. 7, a first etching step (Et1), a first desmutting step (De1), and an electrolytic polishing step (E using an electrolytic solution containing nitric acid and sulfuric acid).
l), the second etching step (Et2), the second desmutting step (De2), and the anodizing step (An) to produce an aluminum support. As shown in FIG. 7, it is usual to carry out a water washing step (Wa1 to Wa4) before and after each step. Note that AC is an AC power supply and DC is a DC power supply.

FIG. 8 is a flow chart showing the most preferred embodiment of the present invention. In the embodiment shown in FIG. 8, the first etching step (Et1), the first desmut step (De)
1), a first electrolytic polishing step (El1) using an electrolytic solution containing nitric acid and sulfuric acid, a second electrolytic polishing step (El2) using an electrolytic solution containing nitric acid, a second etching step (Et2), a second desmutting step (De2), and the anodizing step (A
The aluminum support is produced according to n). As shown in FIG. 8, it is common to carry out a water washing step (Wa1 to Wa5) before and after each step. AC is an AC power source, D
C is a DC power supply.

[Aluminum Plate] The aluminum plate is
It preferably has a thickness of 0.1 to 0.6 mm.
Aluminum plates include pure aluminum plates, as well as aluminum alloy plates and aluminum-coated composite supports. As an aluminum alloy plate, iron was used as a material.
1S aluminum alloy plate containing 1 to 0.5% by mass, silicon 0.03 to 0.3% by mass, copper 0.001 to 0.03% by mass, and titanium 0.002 to 0.1% by mass. Is preferred.

[Etching Step] Before and after the electrolytic polishing step, the aluminum plate is preferably subjected to an etching step of immersing in an alkaline aqueous solution. Examples of the alkali include alkali metal hydroxides (eg, sodium hydroxide, potassium hydroxide), alkali metal carbonates (eg, sodium carbonate) and alkali metal silicates (eg, sodium silicate). The concentration of the alkaline aqueous solution is 1 to 30
Mass% is preferred. The temperature of the alkaline aqueous solution is 20 to 8
The temperature is preferably 0 ° C., and the immersion time is preferably 5 to 250 seconds. Aluminum ions may be added to the etching bath in about one fifth of the alkali.

[Desmut Step] Following the etching step, the aluminum plate is preferably immersed in an aqueous solution of an acid (eg nitric acid, sulfuric acid, hydrochloric acid) to remove smut and neutralize after alkali etching. The acid used in the desmutting step is preferably the same as the acid used in the subsequent step (eg, electrolytic polishing step, anodizing step). For example, nitric acid or sulfuric acid is preferably used as the acid in the desmutting process performed immediately before the electropolishing process using an electrolytic solution containing nitric acid and sulfuric acid. Further, in the desmutting process performed immediately before the anodizing process using the electrolytic solution containing sulfuric acid, it is preferable to use sulfuric acid as the acid. The concentration of the acid aqueous solution is preferably 0.1 to 30 mass%. The temperature of the aqueous acid solution is preferably 5 to 70 ° C., and the immersion time is preferably 5 to 25 seconds.

[Electrolytic Polishing Step] In the present invention, the electrolytic solution used in the electrolytic polishing step (first electrolytic polishing step) contains nitric acid and sulfuric acid. The electrolytic solution used in the electropolishing step (first electropolishing step) preferably contains 5 to 30 g / liter of nitric acid and 0.5 to 10 g / liter of sulfuric acid, and 6 to 15 g / liter of nitric acid and 1 to 1 5
More preferably, it contains g / l of sulfuric acid. Corrosion inhibitors (or stabilizers), if necessary, for the electrolyte
A grain-leveling agent can be added. Examples of corrosion inhibitors include nitrates, chlorides, monoamines, diamines, aldehydes, phosphoric acid, chromic acid, boric acid and ammonium oxalate salts. An appropriate amount (0.
5 to 20 g / l) of aluminum ions may be present.

The temperature of the electrolytic solution is preferably 20 to 70 ° C., more preferably 35 to 55 ° C. There is no particular limitation on the waveform (rectangular wave, trapezoidal wave, sine wave) of the alternating current used in the electrolytic polishing step. It is possible to use single-phase and three-phase alternating currents that are normal commercial alternating currents. The power supply amount is preferably 50 to 600 C / dm ² , and more preferably 100 to 350 C / dm ² . Current density is 10 to 35 A / dm ²
Is preferable, and 15 to 25 A / dm ² is more preferable. The processing time is preferably 10 to 300 seconds.

[Second Electropolishing Step] Following the first electropolishing step, it is preferable to carry out a second electropolishing step using an electrolytic solution containing nitric acid. The electrolytic solution used in the second electropolishing step preferably contains 0.1 to 30 g / liter of nitric acid, and more preferably 0.5 to 25 g / liter of nitric acid. If necessary, a corrosion inhibitor (or stabilizer) or a grain homogenizer can be added to the electrolytic solution. Examples of corrosion inhibitors are nitrates, chlorides,
Included are monoamines, diamines, aldehydes, phosphoric acid, chromic acid, boric acid and ammonium oxalate salts.
Appropriate amount (0.5 to 20 g / liter) in the electrolyte
Aluminum ions may be present.

The temperature of the electrolytic solution is preferably 10 to 60 ° C. There is no particular limitation on the waveform (rectangular wave, trapezoidal wave, sine wave) of the alternating current used in the second electrolytic polishing step. It is possible to use single-phase and three-phase alternating currents that are normal commercial alternating currents. Current density is 5 to 100 A / d
It is preferably m ² . Processing time is 10 to 30
It is preferably 0 seconds. The second electrolytic polishing step preferably makes the average surface roughness of the aluminum support 0.2 to 0.8 μm.

[Anodizing Step] It is preferable to provide an anodizing film on the aluminum plate by the anodizing step. Sulfuric acid or phosphoric acid is generally used as the electrolytic solution in the anodizing step. Mixed acid of sulfuric acid and phosphoric acid (JP-A-55-2
No. 8400) can also be used as the electrolytic solution. However, sulfuric acid is most preferred. The electrolytic solution preferably contains aluminum ions. The anodic oxidation method using sulfuric acid is usually performed with a direct current. However, it is also possible to carry out the anodizing method using alternating current. The concentration of sulfuric acid is preferably 5 to 30% by mass. The electrolysis temperature is preferably in the range of 20 to 60 ° C.
The electrolysis time is preferably 5 to 250 seconds.
The amount of oxide film formed on the surface is 1 to 10 g / m ²
Is preferred. Current density is 1 to 20 A / d
m ² is preferred. In the anodizing method using phosphoric acid, the concentration of phosphoric acid is preferably 5 to 50% by mass.
The electrolysis temperature is preferably 30 to 60 ° C., which is easy. The electrolysis time is preferably 10 to 300 seconds. The current density is preferably 1 to 15 A / dm ² .

[Hydrophilic treatment] The produced aluminum support can be subjected to a hydrophilic treatment, if necessary. Examples of the hydrophilization treatment include silicate (eg, sodium silicate, potassium silicate) treatment (US Pat. No. 2,714,066, 3).
No. 181461), potassium fluorozirconate treatment (US Pat. No. 2,946,638), phosphomolybdate treatment (US Pat. No. 320124).
7), alkyl titanate treatment (GB 1108559), polyacrylic acid treatment (DE 1091433), polyvinylphosphonic acid treatment (DE 1134093, UK 1230447). Description), phosphonic acid treatment (described in JP-B-44-6409), phytic acid treatment (described in US Pat. No. 3,307,951), treatment with a salt of a hydrophilic organic polymer compound and a divalent metal (see JP-A-58-16893 and JP-A-58-18291), hydrophilic treatment by undercoating a water-soluble polymer having a sulfonic acid group (described in JP-A-59-101651), coloring treatment with an acid dye (described in JP-A-59-101651). Japanese Patent Laid-Open No. 60-6435
2), and hydrophilization treatment by silicate electrodeposition (described in US Pat. No. 3,658,662).

[Sealing treatment] After the electropolishing step and the anodizing step, the sealing treatment can be carried out. The sealing treatment can be carried out by immersing the aluminum support in hot water (including a hot aqueous solution of an inorganic salt or an organic salt) or by a steam bath.

[Undercoat layer] An undercoat layer may be provided on the aluminum support. The components of the undercoat layer include hydrophilic polymers (eg, polysaccharides), organic phosphonic acids, organic phosphoric acids, organic phosphinic acids, amino acids (eg, glycine, β-
Alanine), hydroxylamine (eg, triethanolamine) hydrochloride, a water-soluble polymer having a sulfonic acid group (described in JP-A-59-101651) and an acid dye (described in JP-A-60-64352). included. Examples of polysaccharides include cellulose ether (eg, carboxymethyl cellulose)), dextrin and gum arabic. Examples of the organic phosphonic acid include aminoalkylphosphonic acid (eg, 2-aminoethylphosphonic acid), arylphosphonic acid (eg, phenylphosphonic acid,
Naphthylphosphonic acid), alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid. Examples of organic phosphoric acid include phenyl phosphoric acid, naphthyl phosphoric acid, alkyl phosphoric acid and glycerophosphoric acid. Examples of organic phosphinic acids include phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acids and glycerophosphinic acids. The organic phosphonic acid, the organic phosphoric acid and the organic phosphinic acid may have a substituent.

The coating solution for the undercoat layer may use water, methanol, ethanol or methyl ethyl ketone as a solvent. A dye or pigment may be added to the undercoat layer to prevent halation. The coating amount of the undercoat layer after drying is preferably ² to 200 mg / m ² ,
More preferably 5 to 100 mg / m ² .

[Image forming layer] A lithographic printing plate or a lithographic printing original plate can be prepared using an aluminum support. The simplest method is the so-called drawing plate, in which a hydrophobic image is formed by a hand-made technique on an aluminum support,
A lithographic printing plate can be produced. However, generally, a lithographic printing plate precursor having an image forming layer provided on an aluminum support is used to prepare a lithographic printing plate. Various types of image forming layers provided on an aluminum support have been proposed for a lithographic printing plate precursor. In the lithographic printing plate precursor, the hydrophilic surface of the aluminum support functions as a fountain solution-receptive non-image area. Therefore, the image forming layer contains a hydrophobic component, remains on the aluminum support after image formation, and functions as an ink receptive hydrophobic region (image portion). Light or heat is used for the image forming reaction, but light is generally used in terms of resolution.

A typical image forming layer is a layer containing a photopolymerizable monomer (including a photocrosslinkable polymer) or a photodegradable polymer. In the image forming layer containing a photopolymerizable monomer, the monomer in the exposed area is polymerized by imagewise exposure to form an ink-receptive hydrophobic area (image area), then the unexposed area is removed, and the fountain solution is received. The hydrophilic surface of the aluminum support, which functions as a non-image part of the image. In the image forming layer containing a photodegradable polymer, the polymer in the exposed area is decomposed by imagewise exposure, and then the decomposed polymer in the exposed area is removed.
Exposing the hydrophilic surface of the aluminum support which functions as the fountain solution-receptive non-image area. The remaining unexposed area polymer functions as an ink-receptive hydrophobic area (image area).

[0035]

EXAMPLES Example 1 The following treatment was carried out while an aluminum plate (1S material) having a thickness of 0.24 mm was conveyed at a line speed of 30 m / min.

(First etching step) An aluminum plate was immersed in a 20 g / liter sodium hydroxide aqueous solution to carry out an alkali etching treatment. The etching amount was 5 g / m ² . (First water washing step) The aluminum plate was thoroughly washed with water. (First Desmut Step) The aluminum plate was neutralized and washed with a 10 g / liter nitric acid aqueous solution. (Electrolytic polishing step) The aluminum plate was subjected to an electrolytic polishing step in an aqueous solution of 9 g / liter of nitric acid and 5 g / liter of sulfuric acid by using a sinusoidal alternating waveform current (power supply amount 800 C / dm ² ).

(Second Water Washing Step) The aluminum plate was thoroughly washed with water. (Second etching step) An aluminum plate was immersed in a 20 g / liter sodium hydroxide aqueous solution to carry out an alkali etching treatment. Etching amount is 0.5g /
It was m ² . (Third water washing step) The aluminum plate was thoroughly washed with water. (Second Desmut Step) The aluminum plate was neutralized and washed with a 150 g / liter sulfuric acid aqueous solution. (Anodic oxidation process) An aluminum plate was anodized in a 150 g / l sulfuric acid aqueous solution. The amount of the anodized film formed was 2.5 g / m ² . (Fourth water washing step) The aluminum plate was thoroughly washed with water.

(Measurement of Surface Roughness) The surface roughness (Ra) of the produced aluminum support was measured. The results are shown in Table 1. The rough surface was similar to that shown in FIG. 3 (conventional brush polishing treatment only) rather than FIG. 4 (conventional electrolytic polishing treatment only).

[Example 2] An aluminum support was prepared in the same manner as in Example 1 except that the amount of power supplied and the amount of sulfuric acid in the electrolytic polishing step were changed as shown in Table 1. The surface roughness (Ra) of the produced aluminum support was measured. The results are shown in Table 1. As for the state of the rough surface, the state shown in FIG.
Similar to (conventional brush polishing only) was obtained.

[0040]

[Table 1] Table 1 ──────────────────────────────────── Power supply (C / dm ² ) Sulfuric acid amount 100 200 300 400 600 600 800 ──────────────────────────────────── 5g / l 0. 58 0.78 0.91 1.04 1.44 1.83 2 g / l 0.31 0.38 0.42 0.60 1.11 1.49 1 g / l 0.20 0.21 0.38 0 .58 0.90 1.29 ────────────────────────────────────

Example 3 The following treatment was carried out while an aluminum plate (1S material) having a thickness of 0.24 mm was conveyed at a line speed of 30 m / min.

(First etching step) An aluminum plate was immersed in a 20 g / liter sodium hydroxide aqueous solution to carry out an alkali etching treatment. The etching amount was 5 g / m ² . (First water washing step) The aluminum plate was thoroughly washed with water. (First Desmut Step) The aluminum plate was neutralized and washed with a 10 g / liter nitric acid aqueous solution. (First Electropolishing Step) An aluminum plate was subjected to a sine wave alternating waveform current (power supply amount 200 C / dm ² ) at 9 g /
The electropolishing step was performed in an aqueous solution of 1 liter of nitric acid and 2 g / liter of sulfuric acid.

(Second water washing step) The aluminum plate was thoroughly washed with water. (Second electropolishing step) An aluminum plate was subjected to a sine wave alternating waveform current (power supply amount 240 C / dm ² ) to obtain 10 g.
The electropolishing process was carried out in an aqueous nitric acid solution / liter.

(Third water washing step) The aluminum plate was thoroughly washed with water. (Second etching step) An aluminum plate was immersed in a 20 g / liter sodium hydroxide aqueous solution to carry out an alkali etching treatment. Etching amount is 0.5g /
It was m ² . (Fourth water washing step) The aluminum plate was thoroughly washed with water. (Second Desmut Step) The aluminum plate was neutralized and washed with a 150 g / liter sulfuric acid aqueous solution. (Anodic oxidation process) An aluminum plate was anodized in a 150 g / l sulfuric acid aqueous solution. The amount of the anodized film formed was 2.5 g / m ² . (Fifth water washing step) The aluminum plate was thoroughly washed with water.

(Measurement of Surface Roughness) The surface roughness (Ra) of the produced aluminum support was measured and found to be 0.43. As a rough surface state, a state similar to that of FIG. 5 (combination of conventional brush polishing treatment and electrolytic polishing treatment) was obtained rather than FIG. 4 (only conventional electrolytic polishing treatment).

Example 4 An aluminum support was prepared in the same manner as in Example 3 except that the amount of sulfuric acid in the first electrolytic polishing step was changed to 5 g / liter. The surface roughness (Ra) of the produced aluminum support was measured and found to be 0.64. As a rough surface state, a state similar to that of FIG. 5 (combination of conventional brush polishing treatment and electrolytic polishing treatment) was obtained rather than FIG. 4 (only conventional electrolytic polishing treatment).

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a brush polishing device.

FIG. 2 is a schematic sectional view of an electrolytic etching apparatus.

FIG. 3 is a result of measuring a rough surface of an aluminum plate obtained by performing a conventional brush polishing method with a stylus meter.

FIG. 4 is a result of measuring a rough surface of an aluminum plate obtained by performing a conventional electrolytic etching method with a stylus meter.

FIG. 5 is a result of measuring a rough surface of an aluminum plate obtained by performing a conventional electrolytic etching method after a conventional brush polishing method with a stylus meter.

FIG. 6 is a flowchart showing a method (prior art) for manufacturing an aluminum support for a lithographic printing original plate, in which an electrolytic etching method is carried out after a brush polishing method.

FIG. 7 is a flowchart showing a basic aspect of the present invention.

FIG. 8 is a flow chart showing the most preferred embodiment of the present invention.

[Explanation of symbols]

1,11 Aluminum plate 2, 4 roll brush 3 Polishing slurry liquid 5, 6, 7, 8 Support roll 12 guide rolls 13 drum rolls 14 Guide roll 15, 16 electrodes 17 Contact power supply roll 18 Electrolyte 19 Electrolyte supply part 20, 20 'Electrolyte discharge part 21 Circulation tank 22 pumps 23 Alternating waveform power supply 24 Soft Start Zone Electrodes 25 insulator 26 resistors A'electrolytic treatment start point B'Electrolytic treatment end point Al Aluminum plate An anodizing process Bu brush polishing process De desmut process El Electropolishing process Et etching process Wa water washing process AC AC power supply DC AC power supply

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuzo Yoshichi             Fuji-Sha, 4000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture             Shin Film Co., Ltd. (72) Inventor Tsuyoshi Hirokawa             Fuji-Sha, 4000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture             Shin Film Co., Ltd. F-term (reference) 2H114 AA04 AA14 DA04 DA09 DA64                       EA01 EA09 GA05 GA06 GA08                       GA09

Claims (10)

[Claims] 1. A roughening treatment method for an aluminum plate, which comprises immersing an aluminum plate having a smooth surface in an electrolytic solution and roughening the surface by electrolytic polishing, wherein the electrolytic solution contains nitric acid and sulfuric acid. A method for surface-roughening an aluminum plate, characterized by: 2. The roughening treatment method according to claim 1, wherein the electrolytic solution contains 5 to 30 g / liter of nitric acid and 0.5 to 10 g / liter of sulfuric acid. 3. The surface-roughening treatment according to claim 1, wherein after the electropolishing treatment using an electrolytic solution containing nitric acid and sulfuric acid, a second electropolishing treatment using an electrolytic solution containing nitric acid is further performed. Law. 4. The electrolytic solution used in the second electrolytic polishing treatment,
The roughening treatment method according to claim 3, which contains 0.1 to 30 g / liter of nitric acid. 5. An aluminum support for a lithographic printing plate precursor having a multi-layered grain structure formed on the surface only by electrolytic polishing treatment. 6. An etching process for etching an aluminum plate with an alkali; a desmutting process for desmutting an aluminum plate with an acid; a roughening process for electrolytically polishing an aluminum plate with an electrolytic solution containing nitric acid and sulfuric acid; Second etching step of etching with alkali; Second step of desmutting aluminum plate with acid
Desmut process: And the manufacturing method of the aluminum support for lithographic printing original plates which performs the anodizing process of anodizing an aluminum plate in this order. 7. The manufacturing method according to claim 6, wherein nitric acid is used as the acid in the desmutting step. 8. The lithographic printing method according to claim 6, wherein a second roughening step of electrolytically polishing an aluminum plate with an electrolytic solution containing nitric acid is performed between the roughening step and the second etching step. Method for producing aluminum support for original plate. 9. The manufacturing method according to claim 6, wherein sulfuric acid is used as the acid in the second desmutting step. 10. The manufacturing method according to claim 6, wherein an electrolytic solution containing sulfuric acid is used in the anodizing step.