JPH10130897A - Aluminum plate and its surface roughening method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-quality aluminum sheet which obviates streaks even with such aluminum sheet having bearing differences of crystal grains and its surface roughening method. SOLUTION: An indirect power feed system which separates an electrolytic reaction vessel to execute the anode reaction of the aluminum sheet 1 and an electrolytic reaction vessel to execute the cathode reaction thereof is used as a device to be used for an electrolytic polishing treatment in this surface roughening method for the aluminum sheet. The electrolytes of the same kind are used for a power feed vessel 3 to execute the cathode reaction of the aluminum sheet and a vessel 2 to execute the electrolytic polishing treatment by the anode reaction of the aluminum sheet. The treatment is executed by setting at least one or more of the electrolyte compsn., temp. and current density of the power feed vessel at the conditions under which the anode 4 for executing the cathode reaction of the aluminum sheet hardly dissolves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for roughening an aluminum plate used as a support for a lithographic printing plate and an aluminum plate produced by the method. In particular, the present invention relates to a method suitable for roughening an aluminum plate in which streaks tend to occur due to a difference in crystal grain orientation.

[0002]

2. Description of the Related Art Conventionally, there has been a method of increasing the surface area by forming unevenness of a uniform shape on the surface of a metal plate while controlling its depth and distribution, thereby improving the adhesion of a coating layer and the water retention of the surface. Attempted. As one of them, a method of performing a treatment combining one or more of mechanical roughening, chemical etching, and electrochemical roughening is known. In particular, as a method for obtaining a surface shape suitable as an aluminum support for a lithographic printing plate, an electrochemical roughening method using an alternating current or a direct current in an aqueous solution mainly containing nitric acid or hydrochloric acid has been put to practical use.

[0003] As a method of electrochemical surface roughening using a direct current, a method described in Japanese Patent Application Laid-Open No. 1-141094 is known. As a method for generating uniform honeycomb pits by electrochemical surface roughening using alternating current, a method described in Japanese Patent Publication No. 5-65360 is known. In Japanese Patent Publication No. 5-65360, it is preferable that the ratio (Qc / Qa) of the quantity of electricity Qc at the time of cathode and the quantity of electricity Qa at the time of anode of the aluminum plate is in the range of 1 to 2.5. , 2.5 or more, a uniform grain is not formed, and the energy efficiency is reduced. Japanese Patent Application Laid-Open No. 55-137993 discloses an electrochemical surface roughening method using an alternating current (Qc
/ Qa) is preferably in the range of 0.3 to 0.95.

Japanese Patent Application Laid-Open No. 63-176188 discloses that it is effective to perform electrolytic polishing after performing electrochemical surface roughening. Furthermore,
JP-A-6-135175 describes that it is effective to perform chemical etching after mechanical surface roughening or before and after electrochemical surface roughening.

[0005]

As described above, the surface roughening of the aluminum plate is performed by appropriately combining mechanical surface roughening, electrochemical surface roughening, electrolytic polishing, and chemical etching. However, in the case where the aluminum plate to be treated has a difference in crystal grain orientation, a crease-like streak called streak may be generated when chemical etching is performed at 1 g / m ² or more. Therefore, the heat treatment conditions in the aluminum plate rolling process must be severe, which is industrially disadvantageous. As a method for supplying power to the aluminum plate, there are a direct power supply method using a conductor roll and an indirect power supply method (liquid supply method) without using a conductor roll. In the direct power supply system, there is a problem that a spark is easily generated at a contact point between the conductor roll and the aluminum plate. In addition, in the indirect power supply method, there was no material that could withstand the anode material under the liquid conditions used for electrolytic polishing.

The present invention has been made in view of the above circumstances, and provides a high-quality aluminum plate that does not cause streaks even in an aluminum plate having a crystal grain misorientation, and a method of roughening the aluminum plate. The purpose is to:

[0007]

Means for Solving the Problems As a result of intensive studies, the inventors have conducted electrolytic polishing using a liquid power supply system, and the apparatus used for electrolytic polishing at that time employs an electrolytic reaction of an anode reaction and a cathode reaction of an aluminum plate. Using an indirect power supply system with a separate reaction tank, use the same type of electrolyte in the power supply tank and the tank that performs the electropolishing reaction, and control at least one of the composition, temperature, and current density of the electrolyte in the power supply tank As a result, it has been found that the life of the anode can be prolonged, and a stable process without spark can be realized. In addition, it has been found that the electropolishing treatment in an acidic aqueous solution using an aluminum plate as an anode can reduce the occurrence of processing unevenness due to the difference in crystal grain orientation, and have completed the present invention.

That is, the above object is achieved by the following surface roughening method according to the present invention. (1) As an apparatus used for electrolytic polishing, an indirect power supply system in which an electrolytic reaction tank for performing an anodic reaction on an aluminum plate and an electrolytic reaction tank for performing a cathodic reaction are used, and a method for performing a cathode reaction on the aluminum plate is used. The type of the electrolytic solution in the power supply tank and the tank for performing the electropolishing treatment by the anodic reaction of the aluminum plate is the same, and at least one of the electrolytic solution composition, the temperature, and the current density of the power supply tank is adjusted in the power supply tank. A method for roughening an aluminum plate, wherein the aluminum plate is treated under a condition in which an anode for performing a cathode reaction of the aluminum plate is hardly dissolved.

(2) The type of electrolyte or the type and composition of the electrolyte in the power supply tank for electrolytic polishing and the power supply tank for anodic oxidation are set to be the same ( The method for roughening an aluminum plate according to 1).

(3) The above (1) or the above (1), wherein an indirect power supply system is used as an apparatus used for the electrolytic polishing treatment, and a power supply tank for anodizing treatment performed in the next step of the electrolytic polishing treatment is used as a power supply tank. The method for roughening an aluminum plate according to (2).

(4) Lead, platinum or iridium oxide is used for the anode, lead, carbon, stainless steel, aluminum, titanium, tantalum, niobium, zirconium, hafnium, silver or an alloy thereof is used for the cathode, and aluminum facing each electrode is used. The method for roughening an aluminum plate according to any one of the above (1) to (3), wherein the plate is subjected to electrolytic treatment at a current density of 1 to 100 A / dm ² for 1 to 180 seconds.

(5) The method for roughening an aluminum plate according to the above (1), which is performed after mechanical roughening or before and after electrochemical roughening. Plate roughening method.

(6) In the step of (a) mechanical roughening treatment, (b) electropolishing treatment in an acidic aqueous solution, and (c) anodizing treatment, the aluminum plate is subjected to electrolysis in the acidic aqueous solution. A method for surface-roughening an aluminum plate, wherein the polishing treatment is the surface-roughening method according to the above (1).

(7) The aluminum plate is sequentially treated as follows: (a) mechanical surface roughening treatment (b) electrolytic polishing treatment in an acidic aqueous solution or etching treatment in an acid or alkali aqueous solution (c) in an acidic aqueous solution Surface roughening treatment using direct current or alternating current in (d) electrolytic polishing treatment in an acidic aqueous solution, or etching treatment in an acid or alkali aqueous solution (e) anodizing treatment A method for roughening an aluminum plate, wherein the electrolytic polishing in the acidic aqueous solution is the surface roughening method according to the above (1).

(8) An aluminum plate is sequentially subjected to (a) electrolytic polishing treatment in an acidic aqueous solution, or etching treatment in an acid or alkali aqueous solution, and (b) electricity using a direct current in an aqueous solution mainly containing nitric acid. Chemical surface roughening treatment (c) Electropolishing treatment in acidic aqueous solution or etching treatment in acid or alkali aqueous solution (d) Electrochemistry using DC or AC in aqueous solution mainly composed of nitric acid (E) electrolytic polishing in an acidic aqueous solution, or etching in an acid or alkali aqueous solution (f) anodizing treatment, the electrolytic polishing in the acidic aqueous solution is performed. A method for surface roughening an aluminum plate, which is the surface roughening method according to the above (1).

(9) The method according to any one of the above (5) to (8), wherein a desmut treatment is performed after an electrolytic polishing treatment in an acidic aqueous solution or an etching treatment in an acid or alkali aqueous solution. The method for roughening an aluminum plate according to the above.

(10) As the aqueous solution used in the electropolishing treatment, an aqueous solution mainly composed of sulfuric acid or phosphoric acid having a pH of 3 or less, a concentration of 1 to 90 wt%, and a liquid temperature of 10 to 90 ° C. is used. The method for roughening an aluminum plate according to any one of 1) to (9).

(11) The roughness of the aluminum plate according to any one of (1) to (10), wherein the amount of dissolution of the aluminum plate in the electrolytic polishing step is 0.05 to 30 g / m ^2. Surface method.

(12) The above-mentioned (1) to (11), wherein an aluminum plate is used which causes a processing unevenness due to a difference in crystal grain orientation when chemically etched.
The method for roughening an aluminum plate according to any one of the above.

(13) The method for roughening an aluminum plate according to any one of the above (1) to (12), wherein an aluminum plate is omitted from intermediate annealing before cold rolling.

(14) The above (1) to (13), wherein an aluminum plate produced by continuous casting is used.
The method for roughening an aluminum plate according to any one of the above.

(15) An aluminum plate for a lithographic printing plate support produced by the method according to any one of the above (1) to (14), wherein the physical properties of the surface are in the following ranges. (I) The surface shape defined using the value measured by AFM (atomic force microscope) is in the following range. Using an atomic force microscope (AFM) with a resolution of 0.1 μm in the horizontal (X, Y) direction, measurement was performed in a measurement range of 100 μm square, the surface area determined by the approximate three-point method was a, and the upper projected area was b. When the value of a / b (specific surface area) is 1.
15 to 1.5 AF in which the resolution in the horizontal (X, Y) direction is 1.9 μm
AF with an average surface roughness of 0.35 to 1.0 μm measured in a measurement range of 240 μm square using M and a resolution of 1.9 μm in the horizontal (X, Y) direction.
5 to 40% of the rate of inclination of 30 degrees or more measured in a measuring range of 240 μm square using M (II) 85 degree glossiness specified in JIS is 30 or less. (III) When observed with a scanning electron microscope at a magnification of 750, an average diameter of 0.5 to 20 μm is obtained in a field of view of 80 μm.
The area ratio of the honeycomb pit of m is 30 to 100
%.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The roughening method of the present invention will be described below in detail. The aluminum plate used in the present invention is selected from a pure aluminum plate, an alloy plate containing aluminum and a trace amount of a different element, or a plastic film on which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include silicon, iron, nickel, manganese, copper, magnesium, chromium, zinc, bismuth, titanium, and vanadium.
Conventionally known materials, such as JIS A 1050 material, JIS A 3103 material, described in the Aluminum Handbook 4th Edition (1990, Light Metal Association)
JIS A 3005 material, JIS A 1100 material, J
It is possible to use an IS A 3004 material or an alloy obtained by adding 5 wt% or less of magnesium to these materials for the purpose of increasing tensile strength. In the following description, the above-mentioned aluminum alloy plate and laminate plate will be referred to as an aluminum plate.

The above-mentioned aluminum plate may be an aluminum plate manufactured by a normal casting method or a continuous casting and rolling method. As a method of continuous casting and rolling, a twin roll method, a belt caster method, a block caster method, or the like can be used. The present invention is effective for an aluminum plate having a misorientation in crystal grains, and such an orientation difference in crystal grains can be obtained by omitting intermediate annealing before cold rolling or an aluminum plate produced by continuous casting. Therefore, the present invention is suitable for the above aluminum plate. The thickness of the aluminum plate used in the present invention is not particularly limited, and may be a thickness appropriately set according to the purpose of use. For example, when used as a lithographic printing plate support, the thickness is about 0.1 to 0.6 mm.

The present invention provides a lithographic printing plate support by subjecting an aluminum plate to a surface treatment in combination with at least one of mechanical roughening, chemical etching, anodizing treatment, and hydrophilic treatment. The surface can be a suitable surface, but it is characterized by performing electropolishing in an acidic aqueous solution after mechanical roughening and before and after electrochemical roughening. . Hereinafter, preferred modes of each processing will be described.

[Mechanical surface roughening treatment] The mechanical surface roughening referred to in the present invention is performed by rotating a nylon brush roll having a bristle diameter of 0.2 to 0.9 mm and a slurry supplied to the surface of an aluminum plate. It is advantageous to mechanically roughen with a liquid. Known abrasives can be used, but silica sand, quartz, aluminum hydroxide or a mixture thereof is preferred. Regarding the mechanical surface roughening treatment, for example, the methods described in JP-A-6-135175 and JP-B-50-40047 can be suitably used. Of course, the method of spraying the slurry liquid, the method using a wire brush,
For example, a method of transferring the surface shape of a rolling roll having irregularities to an aluminum plate may be used. Other methods are disclosed in JP-A-55-74898 and JP-A-61-1623.
51 and JP-A-63-104889 are also applicable.

[Electropolishing in Acidic Aqueous Solution] In the method of electropolishing an aluminum plate in an acidic aqueous solution as referred to in the present invention, the step of anodically reacting the aluminum plate for electropolishing is carried out by a known aqueous polishing method used for electrolytic polishing. However, an aqueous solution mainly containing sulfuric acid or phosphoric acid is preferred. Particularly preferably, 1 to 90 wt.
% (Preferably 40 to 80 wt%). The liquid temperature is 10 to 90 ° C. (preferably 50 to 80 ° C.), the current density is 1 to 100 A / dm ² (preferably 5 to 80 A / dm ² ).
dm ² ) and the electrolysis time can be selected from the range of 1 to 180 seconds. Sulfuric acid, phosphoric acid, chromic acid, hydrogen peroxide, citric acid, boric acid, hydrofluoric acid, phthalic anhydride and the like may be added to the aqueous solution in an amount of 1 to 50% by weight. In addition to aluminum, an alloy component contained in an aluminum alloy may be contained in an amount of 0 to 10 wt%. As the current, DC, pulse DC, and AC can be used, but continuous DC is preferable.

An apparatus used for the electropolishing treatment is, for example, shown in FIG.
As shown in (1), an indirect power supply system is used in which an electrolytic reaction tank for performing an anodic reaction on the aluminum plate 1 and an electrolytic reaction tank for performing a cathode reaction are separated. Here, the type of the electrolyte 11 in the tank 2 having the cathode 6 and performing the electropolishing reaction is the same as the type of the electrolyte 10 in the tank 3 having the anode 4.
It is preferable that at least one of the composition, temperature, and current density of the electrolytic solution 10 is set to a condition that the anode 4 is hardly dissolved. Further, a single DC power supply 7 is connected to the anode 4 and the cathode 6. The aluminum plate 1 is configured to be appropriately conveyed by pass rollers 8 and nip rollers 9 arranged as shown. In the above apparatus, the anodic reaction of the aluminum plate may be performed first, or the cathodic reaction may be performed first. In particular, it is preferable to perform the cathode reaction of the aluminum plate first. Further, it is preferable that the type of the electrolytic solution or the type and the composition of the electrolytic solution in the power supply tank for the electrolytic polishing treatment and the power supply tank for the anodic oxidation treatment are the same. Here, the type of the electrolytic solution is the type of the acid, and the composition indicates the mixing ratio of the acid. Further, it is preferable that the apparatus used for the electrolytic polishing process uses an indirect power supply system, and the power supply tank uses a power supply tank for anodizing treatment performed in the next step of the electrolytic polishing treatment. Therefore, for example, the tank configuration shown in FIG. 2 can be adopted. As shown in the figure, a tank 5a for performing electropolishing is provided in a region of the electropolishing process 20, and a first cathode 6a is provided in the bath 5a, and a bath 5c for performing anodization is provided in the anodizing region 30. A second cathode 6b is provided in the tank 5c, and a common power supply tank 5b is provided between the two tanks 5a and 5c.
Is provided. It should be noted that a configuration using two DC power supplies 7a and 7b was used as the power supply.

In the electropolishing treatment referred to in the present invention, a known aqueous solution used for electropolishing or anodic oxidation can be used as an electrolysis condition of a power supply tank for performing a cathode reaction of an aluminum plate.
The type of the liquid is preferably an aqueous solution mainly containing sulfuric acid or phosphoric acid. As a liquid composition, nitric acid, sulfuric acid or phosphoric acid is preferably 1 to 50 wt% (preferably 5 to 20 watts).
t%). Liquid temperature 10-60 ° C (preferably 30-50 ° C), current density 1-100A / dm ²
(Preferably 5 to 80 A / dm ² ), and the electrolysis time is 1 to 1
A range of 80 seconds is preferred. In addition, aluminum and aluminum alloy components contained in the aluminum alloy are 0 to 10 watts.
t% may be contained.

As the electrolytic treatment apparatus for the electrolytic polishing treatment, those used in known electrolytic treatments such as a flat type tank and a radial type tank can be used. The flow rate may be either parallel flow or counter flow with respect to the aluminum plate, and is selected from the range of 0.01 to 10000 cm / min. The distance between the aluminum plate and the electrode is 0.3-10c
m is preferable, and 0.8 to 2 cm is particularly preferable. As a power supply method, a direct power supply method using a conductor roll may be used, or an indirect power supply method (liquid power supply method) without using a conductor roll may be used, but the indirect power supply method is particularly preferable. Known electrode materials and structures used in electrolytic treatment and fuel cells can be used. The cathode material is preferably lead, carbon, stainless steel, aluminum, titanium, tantalum, niobium, zirconium, hafnium, silver or an alloy thereof. Particularly, silver is preferable. The material of the anode is preferably lead, ferrite, iridium oxide or platinum. Platinum and iridium oxide are preferably used by cladding or sintering the surface of a corrosion-resistant material such as zirconium or tantalum in an electrolytic solution. The processing surface of the aluminum plate may be the upper surface, the lower surface, or both surfaces.

After the completion of the electropolishing treatment, it is preferable to drain the liquid with a nip roller, or drain the liquid with a nip roller and rinse with water to prevent the treatment liquid from being carried to the next step. Before or after the electropolishing treatment described in the present invention, a chemical etching treatment or a desmut treatment in an acid or alkali aqueous solution may be performed. For chemical etching, see US Pat.
Other known means described in 834398 can be used.

After the electropolishing treatment, the liquid temperature is set to a normal temperature to 70
By performing desmut treatment with sulfuric acid, phosphoric acid, hydrochloric acid, chromic acid, nitric acid or a mixed acid containing two or more of these acids at a concentration of 1 to 90 wt%, a more excellent aluminum support for a lithographic printing plate can be obtained. it can. Further, 0 to 10% by weight of aluminum may be dissolved in the acidic aqueous solution. The processing time is preferably from 1 to 30 seconds. After the end of the desmutting treatment, it is preferable to perform draining with a nip roller, or draining with a nip roller and washing with water to prevent the treatment liquid from being carried to the next step.

[Etching Treatment in Acid or Alkaline Aqueous Solution] The chemical etching treatment in an acid or alkali aqueous solution in the present invention is described in US Pat.
In addition to the method described in Japanese Patent No. 398, known means can be used. As the acid or alkali that can be used in the acidic aqueous solution, those described in JP-A-57-16918 or the like can be used alone or in combination. The treatment is preferably performed at a liquid temperature of 40 to 90 ° C. for 1 to 120 seconds. The concentration of the acidic aqueous solution is 0.5 to 25
wt% is preferable, and the amount of aluminum dissolved in the acidic aqueous solution is preferably 0.5 to 5 wt%. The concentration of the alkaline aqueous solution is preferably 5 to 30 wt%, and the aluminum dissolved in the alkaline aqueous solution is 1 to 30 wt%.
t% is preferred.

After the completion of the etching process, it is preferable to perform draining with a nip roller and washing with water by spraying so as not to carry the processing solution to the next step. When chemical etching is performed using an aqueous solution of a base, smut is generally formed on the surface of aluminum. Therefore, phosphoric acid, nitric acid, sulfuric acid, chromic acid, hydrochloric acid, or a mixed acid containing two or more of these acids is used. Desmut treatment is performed. Furthermore, 0-5 wt% aluminum is contained in the acidic aqueous solution.
% May be dissolved. The solution temperature is from room temperature to 70 ° C., and the processing time is preferably from 1 to 30 seconds. After the end of the desmutting treatment, it is preferable to perform draining with a nip roller and washing with water by spraying so as not to bring the treatment liquid into the next step.

[Aqueous solution mainly composed of nitric acid] The aqueous solution mainly composed of nitric acid according to the present invention is used for electrochemical surface roughening treatment using DC or AC described later. As the aqueous solution mainly composed of nitric acid, those used for usual electrochemical surface roughening treatment using direct current or alternating current can be used. 1 to 100 g / l aqueous nitric acid solution is added to aluminum nitrate, sodium nitrate, ammonium nitrate and the like. Hydrochloric acid or nitric acid compound having hydrochloric acid ions such as nitrate ion, aluminum chloride, sodium chloride, ammonium chloride, etc.
One or more can be used by adding up to 1 g / l to a saturation concentration. In the aqueous solution mainly composed of nitric acid,
Iron, copper, manganese, nickel, titanium, magnesium,
The metal contained in the aluminum alloy such as silica may be dissolved. Preferably, a solution in which aluminum chloride and aluminum nitrate are added to a 0.5 to 2 wt% aqueous solution of nitric acid so that aluminum ions are 3 to 50 g / l is used. The temperature is preferably from 10 to 60C, more preferably from 20 to 50C.

[Aqueous solution mainly composed of hydrochloric acid] The aqueous solution mainly composed of hydrochloric acid according to the present invention is used for electrochemical surface roughening treatment using DC or AC described later. The aqueous solution mainly composed of hydrochloric acid may be one used for a conventional electrochemical surface-roughening treatment using direct current or alternating current. An aqueous solution of hydrochloric acid of 1 to 100 g / l is added to aluminum nitrate, sodium nitrate, ammonium nitrate and the like. Hydrochloric acid or nitric acid compound having hydrochloric acid ions such as nitrate ion, aluminum chloride, sodium chloride, ammonium chloride, etc.
One or more can be used by adding up to 1 g / l to a saturation concentration. In the aqueous solution mainly containing hydrochloric acid,
Iron, copper, manganese, nickel, titanium, magnesium,
The metal contained in the aluminum alloy such as silica may be dissolved. Preferably, a solution in which aluminum chloride and aluminum nitrate are added to a 0.5 to 2 wt% aqueous solution of nitric acid so that aluminum ions are 3 to 50 g / l is used. Further, hypochlorous acid may be added. The temperature is preferably from 10 to 60C, more preferably from 20 to 50C.

[Electrochemical surface roughening treatment using alternating current]
The electrochemical surface-roughening treatment using alternating current in the present invention refers to a method of applying an alternating current between an aluminum plate and an electrode facing the aluminum plate in an electrolytic solution to electrochemically roughen the surface. As the electrolytic solution, those used for electrochemical surface roughening treatment using a known alternating current can be used, but it is advantageous to use an aqueous solution mainly containing nitric acid or an aqueous solution mainly containing hydrochloric acid. . The temperature is preferably from 10 to 60C, more preferably from 20 to 50C. In electrochemical surface roughening in an aqueous solution mainly composed of nitric acid, the average diameter is 0.5 to
It is preferable that pits of 3 μm are generated at a rate of 1 × 10 ^{5 to} 6 × 10 ⁶ / mm ² . However, when the amount of electricity is relatively large, the electrolytic reaction concentrates and honeycomb pits exceeding 3 μm are also generated. A sine wave, a rectangular wave, a trapezoidal wave, a triangular wave, or the like can be used as an AC power supply waveform used for electrochemical surface roughening, but a rectangular wave or a trapezoidal wave is preferable, and a trapezoidal wave is particularly preferable.

Referring to FIG. 3 more specifically,
In the trapezoidal wave, the time tp from the time when the current reaches 0 to the peak is preferably 1 msec, particularly 1 to 10 msec.
c is preferred. Due to the influence of the impedance of the power supply circuit, if tp is less than 1, a large power supply voltage is required at the time of rising of the current waveform, and the equipment cost of the power supply increases. If it is longer than 10 msec, it takes a long time to apply a certain amount of electricity, which leads to an increase in the size of the equipment used for electrochemical surface roughening, and increases the equipment cost.

The condition of one cycle of alternating current used for electrochemical surface roughening is determined by the anode reaction time ta of the aluminum plate.
And the ratio (tc / ta) of the reaction time to the cathode reaction time tc is 1 to 2
0, the ratio (Qc / Qa) of the quantity of electricity Qc at the time of anode to the quantity of electricity Qa at the time of anode is 0.3 to 2;
0, and the anode reaction time ta is preferably in the range of 5 to 1000 msec. In particular, (tc / ta) is 2.5 to 15, and (Qc / Qa) is 2.5 to 1
More preferably, it is 5. In order to form uniform honeycomb pits on the surface of the aluminum plate, it is important to balance the distribution of the oxide film on the surface of the aluminum plate and the generation of the smut mainly composed of aluminum hydroxide. The distribution of the oxide film means the distribution of the starting point of the pitting reaction at the time of the anodic reaction of the aluminum plate.

The method of forming the smut plays an important role in preventing the pitting reaction from occurring again in the portion where the pitting reaction has occurred once, and dispersing the honeycomb pits. In addition, even when the aluminum plate undergoes an anodic reaction, the smut becomes rich in aluminum ion concentration near the interface where the reaction is occurring, and precipitates as aluminum hydroxide. Further, the aluminum plate generates hydrogen gas at the time of the cathode reaction, and the pH at the interface is deposited as an aluminum deposition region. In particular, aluminum hydroxide tends to precipitate in the pitted area of the anodic reaction immediately before the cathodic reaction, and smut is formed in such a way as to cover the pits. It serves to keep the current from being concentrated. On the surface of the aluminum plate that has been electrochemically roughened,
When a smut mainly composed of aluminum hydroxide of 0.8 g / m ² or more is produced, the average diameter is 0.5 to 3 μm.
m honeycomb pits are uniformly dispersed.

When (tc / ta) is less than 1, the starting point of the pitting reaction due to the dissolution of the oxide film formed by the anodic reaction of the aluminum plate decreases, and uniform honeycomb pits cannot be formed. (Tc / ta) is 20
If it is larger, the oxide film generated by the anodic reaction of the aluminum plate is excessively dissolved, the starting point of the pitting reaction becomes too large, and uniform honeycomb pits are not generated,
The surface area does not increase. If (Qc / Qa) is less than 0.3, the starting point of the pitting reaction due to the dissolution of the oxide film generated by the anodic reaction of the aluminum plate is reduced, and uniform honeycomb pits cannot be generated. (Qc
When / Qa) is larger than 20, the oxide film formed by the anodic reaction of the aluminum plate is too dissolved, the starting point of the pitting reaction becomes too large, uniform honeycomb pits are not formed, and the surface area does not increase.

The current density is preferably 10 to 200 A / dm ² on both the anode cycle side Ia and the cathode cycle side Ic of the current at the peak value of the trapezoidal wave. (Ic / Ia)
Is preferably in the range of 0.3 to 20. The total amount of electricity participating in the anodic reaction of the aluminum plate at the time when the electrochemical surface roughening is completed is 10 to 1000 C /
dm ² is preferred, and 100 to 600 C / dm ² is particularly preferred.

As the electrolytic cell used for electrochemical surface roughening using alternating current according to the present invention, an electrolytic cell used for a known surface treatment such as a vertical type, a flat type, and a radial type can be used. Particularly preferred is a radial electrolytic cell as described in JP-A-195300. The electrolytic solution passing through the electrolytic cell may be parallel or counter to the progress of the aluminum web. One or more AC power supplies can be connected to one electrolytic cell. Control the current ratio of the AC anode and cathode applied to the aluminum plate facing the main pole,
It is preferable to provide an auxiliary anode for uniform graining and to dissolve the carbon of the main electrode, and to divide a part of the alternating current. An anodic reaction acting on an 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 rectifying element or a switching element And the ratio of the current value participating in the cathode reaction to the current value participating in the cathode reaction may be controlled.

[Electrochemical surface-roughening using direct current] The electrochemical surface-roughening treatment using direct current as referred to in the present invention means that a direct current is applied between an aluminum plate and an electrode facing the same in an electrolytic solution. A method of applying an electric current to electrochemically roughen the surface. As the electrolytic solution, those used for the electrochemical surface roughening treatment using a known direct current can be used, but it is advantageous to use the aqueous solution mainly containing nitric acid or the aqueous solution mainly containing hydrochloric acid. . The temperature is preferably from 10 to 60 ° C, and from 25 to
50 ° C. is more preferred. As a processing apparatus used for electrochemical surface roughening using a direct current, a known apparatus using a direct current can be used. However, as described in JP-A-1-140994, a pair of anodes or more is used. It is preferable to use a device in which cathodes are alternately arranged. Examples of other known devices include JP-A-6-328876 and JP-A-8-67.
No. 078, JP-A-61-19115 and JP-B-57-4.
An apparatus described in each of the 4760 publications can be used. Alternatively, a direct current may be applied between the conductor roll in contact with the aluminum plate and the cathode facing the aluminum roll to perform electrochemical surface roughening treatment using the aluminum plate as the anode. After the completion of the electrolytic treatment, it is preferable to perform draining with a nip roller and washing with water by spraying so as not to bring the treatment liquid into the next step. The direct current used for electrochemical roughening has a ripple rate of 20
% Is preferable. Current density is 10-200
Preferably A / dm ^2, the aluminum plate electric quantity during anode is preferably not 100~1000C / dm ^2. The anode can be selected from known oxygen generating electrodes such as ferrite, iridium oxide, platinum, and platinum clad or plated with a valve metal such as titanium, niobium, or zirconium. The cathode can be selected from carbon, platinum, titanium, niobium, zirconium, stainless steel, and an electrode used for a fuel cell cathode.

[Anodic Oxidation Treatment] Anodizing treatment is performed to increase the abrasion resistance of the surface of the aluminum plate. As the electrolyte used for the anodizing treatment, any electrolyte can be used as long as it forms a porous oxide film. Generally, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixture thereof is used. The concentration of these electrolytes is appropriately determined by the type of electrolyte.
The anodizing treatment conditions vary depending on the electrolyte used, and thus cannot be specified unconditionally.
~ 80wt%, liquid temperature 5 ~ 70 ° C, current density 1 ~ 60A
/ Dm ² , voltage 1 to 100 V, electrolysis time 10 seconds to 300
It is appropriate if it is in the range of seconds. In the sulfuric acid method, the treatment is usually performed with a direct current, but an alternating current can also be used. The amount of the anodic oxide film is suitably in the range of 1 to 10 g / m ² . When the amount is less than 1 g / m ² , the printing durability is insufficient, and the non-image portion of the lithographic printing plate is easily damaged, and at the same time, the ink adheres to the scratched portion, that is, so-called scratch stain is easily generated. .

[Hydrophilic treatment] After the anodic oxidation treatment, the surface of the aluminum plate is subjected to a hydrophilic treatment if necessary. Examples of the hydrophilic treatment used in the present invention include U.S. Pat. Nos. 2,714,066, 3,181,461, and
There is an alkali metal silicate (for example, sodium silicate aqueous solution) method as disclosed in each of 2807334 and 3902734. In this method, an aluminum plate is immersed in an aqueous solution of sodium silicate or electrolytically treated. Other Japanese Patent Publication No. 36-22063
Potassium fluoride zirconate disclosed in US Pat. No. 3,276,868 and US Pat. No. 4,153,461.
And the method of treating with polyvinyl phosphonic acid as disclosed in the specifications of Japanese Patent No. 4689272 and No. 4689272.

[Sealing Treatment] After the surface roughening treatment and the anodic oxidation treatment, it is preferable to perform a sealing treatment. Such a sealing treatment is performed by immersion in hot water and a hot aqueous solution containing an inorganic salt or an organic salt, a steam bath or the like.

Hereinafter, a process for producing an aluminum support for a lithographic printing plate using the surface roughening method of the present invention will be described. [Manufacturing process-1] An aluminum plate is treated in the following order. (A) Electropolishing treatment in an acidic aqueous solution or chemical etching treatment in an acid or alkali aqueous solution: This treatment is performed by using a rolling oil, a natural oxide film,
This is performed for the purpose of removing dirt and the like and uniformly performing the next electrochemical surface roughening. The dissolution amount of the aluminum plate at this time is preferably 1 to 30 g / m ² , and 1.5 to ² g / m 2.
More preferably, 0 g / m ^{2 is} dissolved. (B) Electrochemical surface roughening treatment using direct current or alternating current in an aqueous solution mainly containing nitric acid or hydrochloric acid:
Craters or honeycomb or cubic pits having an average diameter of about 0.1 to 3 μm
It is generated at an area ratio of 0 to 100%, and has an effect that the non-image portion of the printing plate is hardly stained and the printing durability is improved. (C) electrolytic polishing treatment in an acidic aqueous solution or chemical etching treatment in an acid or alkali aqueous solution: the treatment mainly comprises aluminum hydroxide produced by the electrochemical surface roughening treatment. This is performed for the purpose of removing the smut component and smoothing the edge portions of the generated pits and improving the stain performance when the printing plate is obtained. Dissolution amount of the aluminum plate at this time preferably be 0.05-5 g / m ² dissolution, and more preferably 0.1 to 3 g / m ² dissolution. (D) Anodizing treatment: This treatment is performed to increase the abrasion resistance of the surface of the aluminum plate.

[Manufacturing Method-2] An aluminum plate is treated in the following order. (A) Mechanical roughening treatment (b) Electropolishing treatment in an acidic aqueous solution or chemical etching treatment in an acid or alkali aqueous solution: This treatment is generated by the mechanical roughening. It is performed for the purpose of dissolving the edge portion of the unevenness obtained, obtaining a surface having a smooth undulation, and obtaining a printing plate having good stain performance. At this time, the dissolution amount of the aluminum plate is preferably 5 to ²⁰ g / m ² . (C) Electrochemical surface roughening treatment using a direct current or an alternating current in an aqueous solution mainly containing nitric acid or hydrochloric acid:
Craters or honeycomb or cubic pits having an average diameter of about 0.1 to 3 μm
It is generated at an area ratio of 0 to 100%, and has an effect of preventing the non-image portion of the printing plate from being stained and improving the printing durability. (D) electrolytic polishing treatment in an acidic aqueous solution or chemical etching treatment in an acid or alkali aqueous solution: the treatment mainly includes aluminum hydroxide produced by the electrochemical surface roughening treatment. This is performed for the purpose of removing the smut component and smoothing the edge portions of the generated pits and improving the stain performance when the printing plate is obtained. Dissolution amount of the aluminum plate at this time preferably be 0.05-5 g / m ² dissolution, and more preferably 0.1 to 3 g / m ² dissolution. (E) Anodizing treatment: This treatment is performed to increase the abrasion resistance of the surface of the aluminum plate.

[Manufacturing Step-Part 3] The aluminum plate is treated in the following order. (A) Electropolishing treatment in an acidic aqueous solution or chemical etching treatment in an acid or alkali aqueous solution: This treatment is performed by using a rolling oil, a natural oxide film,
This is performed for the purpose of removing dirt and the like and uniformly performing the next electrochemical surface roughening. The dissolution amount of the aluminum plate at this time is preferably 1 to 30 g / m ² , and 1.5 to ² g / m 2.
More preferably, 0 g / m ^{2 is} dissolved. (B) Electrochemical surface roughening treatment using direct current or alternating current in an aqueous solution mainly containing nitric acid or hydrochloric acid:
Craters or honeycombs or cubic pits having an average diameter of about 0.1 to 20 μm are formed on the aluminum surface at an area ratio of 30 to 100% to improve the resistance to non-image areas of the printing plate and the printing durability. There is action. (C) electrolytic polishing treatment in an acidic aqueous solution or chemical etching treatment in an acid or alkali aqueous solution: the treatment includes the smut generated by the electrochemical roughening and the edge portion of the pit or This is performed for the purpose of dissolving a plateau portion where no pits are formed, and obtaining a surface having smooth irregularities. Further, the non-image portion of the printing plate is less likely to be stained and has an effect of improving printing durability. Dissolution amount of the aluminum plate at this time preferably be 1 to 30 g / m ² dissolution, and more preferably 1.5 to 20 / m ² dissolution. (D) Electrochemical surface roughening treatment using DC or AC in an aqueous solution mainly composed of nitric acid or hydrochloric acid:
Craters or honeycomb or cubic pits having an average diameter of about 0.1 to 3 μm
It is generated at an area ratio of 0 to 100%, and has an effect of preventing the non-image portion of the printing plate from being stained and improving printing durability. (E) Electropolishing treatment in an acidic aqueous solution or chemical etching treatment in an acid or alkali aqueous solution: This treatment is mainly made of aluminum hydroxide produced by the electrochemical surface roughening treatment. This is performed for the purpose of removing the smut component, smoothing the edge portion of the generated pit, and improving the stain performance of the printing plate. Dissolution amount of the aluminum plate at this time preferably be solutions 0.05-5 g / m ^2, and more preferably 0.1 to 3 g / m ² dissolution. (F) Anodizing treatment: This treatment is performed to enhance the abrasion resistance of the surface of the aluminum plate.

As described above, an excellent aluminum support for a lithographic printing plate having the following physical property values is produced by surface treatment of an aluminum plate by combining the surface roughening treatment and various treatments according to the present invention. Can be. In the present invention, the aluminum support before the application of the photosensitive layer is made of JI
The glossiness at 85 degrees defined by SZ9741-1983 is preferably 30 or less, and the amount of dampening water on the printing press exceeding 30 becomes difficult to see. When observed with a scanning electron microscope, the average pit diameter is 0.5 to 20 μm, preferably 0.5 to 20 μm.
The proportion of the portion where honeycomb pits or crater-like pits having a size of 3 μm occupy 30 to 1 of the total surface area.
00% is preferable, and if it is less than 30%, the surface quality of the printing plate becomes poor, and the proofreading work becomes difficult.

The area of the portion where honeycomb pits or crater-like pits are generated is determined as follows. A SEM photograph at a magnification of 1500 times is taken from directly above the sample with a scanning electron microscope. Fuji Photo Film Co., Ltd.
Enlarge and copy to 200%. A transparent PET sheet is superimposed on the image enlarged and copied to 200%, and the area where the pit is generated is manually painted black. The image of the PET sheet was captured by a flatbed scanner, binarized by Photoshop on a Macintosh, and then the area of the black portion was calculated. The average surface roughness, the specific surface area, and the ratio of the area having an inclination of 30 ° or more (a30) calculated based on the three-dimensional surface shape measured by AFM according to the present invention are the blanket-like stain performance (blank stain), This is related to the difficulty of smearing (the difficulty of entanglement) and the printing durability of the halftone dot non-image area, and has a trade-off relationship with each other, but the following range is preferable. Using an AFM having a resolution of 0.1 μm in the horizontal (X, Y) direction and measuring in a measurement range of 100 μm square, when the surface area obtained by the approximate three-point method is a and the upper projected area is b, a
The value (specific surface area) of / b is preferably from 1.15 to 1.50, particularly preferably from 1.15 to 1.30. If it is less than 1.15, the adhesion between the photosensitive layer and the support will be poor (the printing durability will be poor), and if it exceeds 1.50, the blank stain performance will be poor.
AFM with a horizontal (X, Y) resolution of 1.9 μm
The average surface roughness measured in a measuring range of 240 μm square is preferably 0.35 to 1.0 μm, particularly 0.35 to
0.8 μm is preferred. If the average surface roughness is less than 0.35 μm, the non-image area is more likely to be stained when the average surface roughness is larger than 1.0 μm. A where the resolution in the horizontal (X, Y) direction is 1.9 μm
It is preferable that the rate of inclination of 30 degrees or more measured in a measurement range of 240 μm square using FM is 5 to 40%. If the ratio of the inclination of 30 degrees or more is less than 5%, the non-image portion is likely to be stained on the halftone dot, and if it is more than 40%, the non-image portion is easily stained on the blanket. The fractal dimension representing the preferred surface morphology in the present invention is 10 fold using an AFM having a resolution in the horizontal (X, Y) direction of 0.1 μm or 1.9 μm.
The fractal dimension obtained by a box counting method, a scale conversion method, a cover method, a radius of gyration method, a density correlation function method, or the like measured in a measurement range of 0 μm square or 240 μm square is 2.1 to 2.5.

The atomic force microscope (Atomic Force Microscope) used for the measurement in the present invention:
AFM) is SP13700 manufactured by Seiko Electronic Industry Co., Ltd.
In the measurement, set the aluminum plate cut into a size of 1 cm square on the horizontal sample stage on the piezo scanner, approach the sample surface with the cantilever, and scan in the XY directions when reaching the area where the atomic force acts At this time, the unevenness of the sample was captured by piezo displacement in the Z direction. The piezo scanner used was capable of scanning XY 150 μm and Z 10 μm. The cantilever is SI-DF20 manufactured by NANOPROBE and has a resonance frequency of 120 to 150 kHz.
z and a spring constant of 12 to 20 N / m, and were measured in a DFM mode (Dynamic Force Mode). Further, the obtained three-dimensional data was subjected to least-squares approximation to correct a slight inclination of the sample, thereby obtaining a reference plane. XY
240 μm when measuring in the direction of 1.9 μm
The angle was measured (4 fields of 120 μm square), the resolution in the Z direction was 1 nm, and the scan speed was 60 μm / sec. When the resolution in the XY directions is 0.1 μm, 1
A measurement of 00 μm square (4 fields of view of 50 μm square) is performed, the resolution in the Z direction is 1 nm, and the scan speed is 25 μm / sec.
Met. The pitch of the undulation of the large waves was calculated by performing frequency analysis on the three-dimensional data. The average surface roughness is JIS
Center line average roughness R defined in B0601-94
a is extended three-dimensionally. The surface gradient is obtained by extracting three adjacent points from the three-dimensional data, calculating the angle between a small triangle formed by the three points and the reference plane for all data, obtaining a gradient distribution curve, and calculating the gradient from this. The ratio of 30 degrees or more was calculated. The pit diameter of the medium wave is obtained by calculating the upper projected area S surrounded by the edge of the pit, and 2 · (S / π)
^It was calculated by ^1/2 . The surface area was determined by extracting three adjacent points from the three-dimensional data and calculating the total area of the small triangles formed by the three points.

A conventionally known photosensitive layer is provided on the lithographic printing plate support thus obtained, and a photosensitive lithographic printing plate can be obtained. The resulting lithographic printing plate has excellent performance. The photosensitive substance used in the photosensitive layer is not particularly limited, and those usually used for photosensitive lithographic printing plates can be used. For example, various types described in JP-A-6-135175 can be used. Further, the photosensitive layer may be either a negative type or a positive type. Aluminum undercoat layer (intermediate layer) if necessary before coating the photosensitive layer
Is provided. As the organic undercoat layer provided on the undercoat layer, those conventionally known can be used, and for example, those described in JP-A-6-135175 can be used. Further, a mat layer may be provided on the photosensitive layer in order to improve the adhesion to the lith film during vacuum printing. Further, a back coat layer may be provided on the back surface for the purpose of preventing the dissolution of aluminum during development.

According to the present invention, P is treated not only on one side but also on both sides.
It can also be applied to the production of S plates. Further, the present invention can be applied not only to the roughening of the aluminum support for lithographic printing plates, but also to the roughening of any aluminum plate.

The present invention can be further clarified by the following examples. However, the present invention is not limited by these examples. (Example 1) The intermediate annealing treatment before the cold rolling step was omitted,
The treatment shown in Table 1 was performed using a JIS A 1050 aluminum plate having a thickness of 0.24 mm and a width of 1030 mm in which streaks were easily generated by chemical etching in an acid or alkali aqueous solution.

[0057]

[Table 1]

The etching methods in Table 1 are as follows. -Electropolishing treatment in phosphoric acid aqueous solution (Example 1-1):
An aqueous solution containing an aluminum plate containing 60 wt% of phosphoric acid 6
Electrolytic polishing was performed at 0 ° C. at a current density of 20 A / dm ² for 30 seconds using the aluminum plate as an anode. Thereafter, a water washing treatment was performed. -Electropolishing treatment in sulfuric acid aqueous solution (Example 1-2): An aqueous solution containing an aluminum plate at 50 wt% sulfuric acid at 60 ° C.
Then, electrolytic polishing was performed at a current density of 20 A / dm ² for 30 seconds using the aluminum plate as an anode. Thereafter, a water washing treatment was performed. Chemical etching treatment in a NaOH solution (Comparative Example 1): An aluminum plate is heated to 60 ° C. in an aqueous solution containing 26 wt% of NaOH and 6.5 wt% of aluminum ions.
The aluminum plate was etched by dipping for 2 seconds. Thereafter, a water washing treatment was performed.

(Example 2) The intermediate annealing treatment before the cold rolling step was omitted, and the thickness was increased to a value that streaks were easily generated by chemical etching in an acid or alkali aqueous solution.
The treatment was performed using a JIS A 1050 aluminum plate having a size of 24 mm and a width of 1030 mm. First, specific gravity 1.1
While the suspension of silica sand and water of No. 2 was supplied to the surface of the aluminum plate as a polishing slurry, mechanical surface roughening was performed with a rotating roller-shaped nylon brush. Nylon brush is made of 6/10 nylon, hair length 50m
m, hair diameter was 0.295 mm. The nylon brush was planted so that holes were made in a stainless steel cylinder having a diameter of 300 mm to make it dense. Three rotating brushes were used.
The distance between the two support rollers (Φ200 mm) below 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 the load before pressing the brush roller against the aluminum plate. The direction of rotation of the brush was the same as the direction of movement of the aluminum plate. Then, the processing of Table 2 was performed.

[0060]

[Table 2]

The etching method in Table 2 is as follows. -Electropolishing treatment in phosphoric acid aqueous solution (Example 2-1):
An aqueous solution containing an aluminum plate containing 60 wt% of phosphoric acid 6
Electrolytic polishing was performed at 0 ° C. at a current density of 20 A / dm ² for 70 seconds using the aluminum plate as an anode. Thereafter, a water washing treatment was performed. -Electropolishing treatment in sulfuric acid aqueous solution (Example 2-2): an aqueous solution containing an aluminum plate at 50 wt% sulfuric acid at 60 ° C
Then, electrolytic polishing was performed at a current density of 20 A / dm ² for 30 seconds using the aluminum plate as an anode. Thereafter, a water washing treatment was performed. Chemical etching treatment in a NaOH solution (Comparative Example 2): An aluminum plate was heated to 60 ° C. in an aqueous solution containing 26 wt% of NaOH and 6.5 wt% of aluminum ions.
The aluminum plate was etched by dipping for 2 seconds. Thereafter, a water washing treatment was performed. When the surface of the aluminum plate treated according to Example 2-1, Example 2-1 and Comparative Example 2 was observed with a scanning electron microscope, the sharp portions formed by the brush and the slurry liquid were dissolved, and the surface was smoothed. The surface had a swell of 5 to 30 μm pitch.

(Example 3) The intermediate annealing treatment before the cold rolling step was omitted, and the thickness at which streak was easily generated by chemical etching in an acid or alkali aqueous solution was set to 0.
Using a JIS A 1050 aluminum plate having a width of 24 mm and a width of 1030 mm, the treatment was continuously performed in the following order. (A) The aluminum plate was subjected to electrolytic polishing at 70 ° C. in an aqueous solution containing 50 wt% of sulfuric acid at a current density of 20 A / dm ² for 40 seconds using the aluminum plate as an anode. afterwards,
Washing with a spray was performed. (B) Electrochemical surface roughening treatment was continuously performed using an AC voltage. At this time, the electrolytic solution was a 1 wt% aqueous solution of nitric acid (containing 0.5 wt% of aluminum ions and 0.007 wt% of ammonium ions), and the liquid temperature was 45 ° C. The AC power supply waveform (see FIG. 3) is such that the time tp until the current value reaches a peak from zero is 1 msec, the duty ratio is 1: 1,
Electrochemical surface roughening treatment was performed using a trapezoidal rectangular wave alternating current and a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The current density is 60 at the peak value of the current.
A / dm ^2, the amount of electricity the aluminum plate was 230C / dm ² as the total quantity of electricity when the anode. 5% of the current flowing from the power supply was diverted to the auxiliary anode. Thereafter, water washing by spraying was performed. (C) Electrolytic polishing was performed at 70 ° C. in an aqueous solution containing 50 wt% of sulfuric acid at a current density of 4 A / dm ² for 2.5 seconds using an aluminum plate as an anode. About 0.1g of aluminum plate
/ M ² dissolved, removal of a smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening was performed using alternating current at the preceding stage, and dissolution of the edge portion of the generated pit, and edge portion Was smoothed. Then, it was washed with water by spraying. (D) An aqueous solution of 15 wt% sulfuric acid (containing 0.5 wt% of aluminum ions) at a liquid temperature of 35 ° C. using a DC voltage, a current density of 2 A / dm ² and an anodized film amount of 2.4 g.
/ M ² . Thereafter, water washing by spraying was performed. (E) Sodium silicate 2.5 wt% for the purpose of hydrophilic treatment
%, And immersed in an aqueous solution of 70 ° C. for 14 seconds, then washed with a spray and dried. After each treatment and washing with water, the liquid was drained with a nip roller.

When the surface of the aluminum plate treated as described above was observed with a JEOL FESEM, honeycomb pits having an average diameter of 0.5 to 3.0 μm were found.
In addition, no streaks due to the difference in crystal grain orientation occurred on the surface of the aluminum plate. Further, the intermediate layer and the photosensitive layer were applied to the aluminum plate and dried to prepare a negative PS plate having a dry film thickness of 2.0 g / m ² . When printing was performed using this PS plate, a good printing plate was obtained.

Example 4 The procedure was performed in the same manner as in Example 3 except that the step (e) was not immersed in the aqueous sodium silicate solution. No streak caused by the difference in crystal grain orientation was generated on the surface of the treated aluminum plate. Further, an intermediate layer and a positive photosensitive layer were applied to this aluminum plate and dried to prepare a PS plate. When this PS plate was printed, it was a good printing plate.

(Example 5) The intermediate annealing treatment before the cold rolling step was omitted, and the thickness at which streak was easily generated by chemical etching in an acid or alkali aqueous solution was set to 0.
Using a JIS A 1050 aluminum plate having a width of 24 mm and a width of 1030 mm, the treatment was continuously performed in the following order. (A) While supplying a suspension of silica sand and water having a specific gravity of 1.12 as a polishing slurry liquid to the surface of an aluminum plate, mechanical roughening was performed with a rotating roller-shaped nylon brush. The nylon brush was made of nylon 6/10, and had a bristle length of 50 mm and a bristle diameter of 0.295 mm. The nylon brush was planted so that holes were made in a stainless steel cylinder having a diameter of 300 mm to make it dense. Three rotating brushes were used. Two support rollers under the brush (Φ2
00 mm) was 300 mm. The brush roller has a load of the drive motor for rotating the brush, which is 7% of the load before pressing the brush roller against the aluminum plate.
Pressed down to kw plus. The direction of rotation of the brush was the same as the direction of movement of the aluminum plate. (B) The aluminum plate was subjected to electrolytic polishing at 70 ° C. in an aqueous solution containing 50 wt% of sulfuric acid at a current density of 20 A / dm ² for 30 seconds using the aluminum plate as an anode. As a result, the sharp portions of the irregularities generated by the brush and the slurry liquid at the previous stage were dissolved to obtain a smooth surface having a swell of 5 to 30 μm pitch. Thereafter, washing with water was performed by spraying. (C) Electrochemical surface roughening treatment was continuously performed using an AC voltage. At this time, the electrolytic solution was a 1 wt% aqueous solution of nitric acid (containing 0.5 wt% of aluminum ions and 0.007 wt% of ammonium ions), and the liquid temperature was 45 ° C. The AC power supply waveform performs electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave AC with a time tp until the current value reaches a peak from zero to a peak of 1 msec, a duty ratio of 1: 1. Was. Ferrite was used for the auxiliary anode. The current density is 60 A / dm ² at the peak value of the current,
The quantity of electricity is the sum of the quantity of electricity when the aluminum plate is the anode, 20
It was 0 C / dm ² . 5% of the current flowing from the power supply was diverted to the auxiliary anode. Thereafter, water washing by spraying was performed. (D) At 70 ° C. in an aqueous solution containing 50% by weight of sulfuric acid, electrolytic polishing was performed at an electric current density of 10 A / dm ² for 11 seconds using an aluminum plate as an anode. As a result, about 1 g / m ² of the aluminum plate was dissolved, and a smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening was performed using alternating current at the preceding stage was removed. The edge part melted and the edge part became smooth. afterwards,
Washed with spray. (E) An aqueous solution of 15 wt% sulfuric acid (containing 0.5 wt% of aluminum ions) at a liquid temperature of 35 ° C., a DC voltage, a current density of 2 A / dm ² and an anodized film amount of 2.4 g.
/ M ² . Thereafter, water washing by spraying was performed. (F) For the purpose of hydrophilic treatment, 2.5 wt% sodium silicate
%, And immersed in an aqueous solution of 70 ° C. for 14 seconds, then washed with a spray and dried. After each treatment and washing with water, the liquid was drained with a nip roller.

When the surface of the aluminum plate treated as described above was observed with a JEOL FESEM, 5 to 30
Honeycomb pits having an average diameter of 0.5 to 3.0 μm were superimposed on large undulations of μm. In addition, no streaks due to the difference in crystal grain orientation occurred on the surface of the aluminum plate. Further, the intermediate layer and the photosensitive layer were applied to this aluminum plate and dried to obtain a dry film thickness of 2.0 g /
A negative PS plate of m ² was prepared. When printing was performed using this PS plate, a good printing plate was obtained.

Example 6 Example 6 was carried out under exactly the same conditions as in Example 5 except that the sample was not immersed in the aqueous sodium silicate solution of (f). No streak caused by the difference in crystal grain orientation was generated on the surface of the treated aluminum plate. Further, an intermediate layer and a positive photosensitive layer were applied to this aluminum plate and dried to prepare a PS plate. When this PS plate was printed, it was a good printing plate.

(Example 7) The intermediate annealing treatment before the cold rolling step was omitted, and the thickness at which streak was easily generated by chemical etching in an acid or alkali aqueous solution was set to 0.
Using a JIS A 1050 aluminum plate having a width of 24 mm and a width of 1030 mm, the treatment was continuously performed in the following order. (A) The aluminum plate was subjected to electrolytic polishing at 70 ° C. in an aqueous solution containing 70 wt% of phosphoric acid at a current density of 40 A / dm ² for 20 seconds using the aluminum plate as an anode. Thereafter, water washing by spraying was performed. (B) Electrochemical surface roughening treatment was continuously performed using a DC voltage. At this time, the electrolytic solution was a 1 wt% aqueous solution of nitric acid (containing 0.5 wt% of aluminum ions and 0.007 wt% of ammonium ions), and the liquid temperature was 45 ° C. Titanium was used for the anode. 20% ripple rate for electrolysis
The following DC voltage was used. The current density is 50 A / dm ² , and the quantity of electricity is 400 in total of the quantity of electricity when the aluminum plate is the anode.
C / dm ² . The cathode and the anode were a pair. Thereafter, water washing by spraying was performed. (C) Electrolytic polishing was performed at 70 ° C. in an aqueous solution containing 70% by weight of phosphoric acid at a current density of 40 A / dm ² for 15 seconds using an aluminum plate as an anode. Then, it was washed with water by spraying. (D) Electrochemical surface roughening treatment was continuously performed using an AC voltage. At this time, the electrolytic solution was a 1 wt% aqueous solution of nitric acid (containing 0.5 wt% of aluminum ions and 0.007 wt% of ammonium ions), and the liquid temperature was 45 ° C. The AC power supply waveform is an electrochemical roughening process using a trapezoidal rectangular wave AC with a time TP until the current value reaches a peak from zero to a peak, a duty ratio of 1: 1, and a carbon electrode as a counter electrode. Was. Ferrite was used for the auxiliary anode. The current density is 60 A / dm ² at the peak value of the current,
The quantity of electricity is 15 as the sum of the quantity of electricity when the aluminum plate is the anode.
It was 0 C / dm ² . 5% of the current flowing from the power supply was diverted to the auxiliary anode. Thereafter, water washing by spraying was performed. (E) At 70 ° C. in an aqueous solution containing 70 wt% of phosphoric acid, an electrolytic polishing treatment was performed at a current density of 20 A / dm ² for 5 seconds using an aluminum plate as an anode. As a result, about 1 g / m ² of the aluminum plate was dissolved, and a smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening was performed using alternating current at the preceding stage was removed. The edge part melted and the edge part became smooth. Then, it was washed with water by spraying. (F) An aqueous solution of 15 wt% sulfuric acid (containing 0.5 wt% of aluminum ions) at a liquid temperature of 35 ° C. using a DC voltage, a current density of 2 A / dm ² and an anodized film amount of 2.4 g.
/ M ² . Thereafter, water washing by spraying was performed. (G) For the purpose of hydrophilic treatment, 2.5 wt% sodium silicate
%, And immersed in an aqueous solution of 70 ° C. for 14 seconds, then washed with a spray and dried. After each treatment and washing with water, the liquid was drained with a nip roller. Observation of the surface of the aluminum plate treated as described above with a JEOL FESEM revealed that honeycomb pits having an average diameter of 0.5 to 3.0 μm overlapped large undulations of 5 to 20 μm. In addition, no streaks due to the difference in crystal grain orientation occurred on the surface of the aluminum plate. Further, the intermediate layer and the photosensitive layer were applied to the aluminum plate and dried to prepare a negative PS plate having a dry film thickness of 2.0 g / m ² . When printing was performed using this PS plate, a good printing plate was obtained.

(Example 8) The same procedure as in Example 7 was carried out except that (g) the sodium silicate aqueous solution was not used. No streak caused by the difference in crystal grain orientation was generated on the surface of the treated aluminum plate. Further, an intermediate layer and a positive photosensitive layer were applied to this aluminum plate and dried to prepare a PS plate. When this PS plate was printed, it was a good printing plate.

Example 9 An aluminum plate was treated in the same manner as in Example 7, except that the aqueous solution of phosphoric acid used in the electropolishing treatment was changed to a 50 wt% aqueous solution of sulfuric acid. No streak caused by the difference in crystal grain orientation was generated on the surface of the treated aluminum plate.

(Example 10) The intermediate annealing treatment before the cold rolling step was omitted, and streak was easily generated by chemical etching in an acid or alkali aqueous solution. , JIS A 105
The treatment was continuously performed using a 0 aluminum plate. (A) While supplying a suspension of an abrasive (aluminum hydroxide) having a specific gravity of 1.12 and water as a polishing slurry to the surface of an aluminum plate, mechanically roughening is performed by a rotating roller-shaped nylon brush. Was. The nylon brush was made of nylon 6/10, and had a bristle length of 50 mm and bristle diameters as shown in Table 3. The nylon brush was planted so that holes were made in a stainless steel cylinder having a diameter of 300 mm to make it dense. Three rotating brushes were used. The distance between the two support rollers (Φ200mm) under the brush is 300
mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus the load before pressing the brush roller against the aluminum plate. The direction of rotation of the brush was the same as the direction of movement of the aluminum plate. (B) The aluminum plate was spray-etched at a sodium hydroxide concentration of 26 wt%, an aluminum ion concentration of 6.5 wt%, and a liquid temperature of 75 ° C. to dissolve the aluminum plate at 15 g / m ² . Thereafter, washing with water was performed by spraying. (C) Desmut treatment was performed by spraying with a 1 wt% nitric acid aqueous solution (containing 0.5 wt% aluminum ions) at a liquid temperature of 30 ° C., followed by washing with spray.
As the nitric acid aqueous solution used for the desmutting, a waste liquid from a step of performing electrochemical surface roughening using an alternating current in a nitric acid aqueous solution was used. (D) Electrochemical surface roughening treatment was continuously performed using an AC voltage having a frequency of 0.67 Hz. At this time, the electrolytic solution is a 1 wt% aqueous solution of nitric acid (aluminum ion 0.5 w
t%, containing 0.007% by weight of ammonium ion), and the liquid temperature was 45 ° C. The AC power supply waveform was subjected to electrochemical surface roughening treatment using a trapezoidal rectangular wave AC with a carbon electrode as a counter electrode, with a time tp until the current value reaches a peak from zero to 1 msec. Qc / Qa = 2, tc / ta =
2, la = lc. The quantity of electricity was as shown in Table 3 as the sum of the quantity of electricity when the aluminum plate was the anode. The quantity of electricity was changed according to the set value of la. Thereafter, water washing by spraying was performed. (E) An electrolytic polishing treatment was performed at 60 ° C. in an aqueous solution containing 50 wt% of sulfuric acid using an aluminum plate as an anode. The current density used was a direct current of 10 A / dm ² . The aluminum plate was melted in the amount shown in Table 3 to remove the smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening was performed using alternating current in the preceding stage, and to remove the generated pits. The edge portion was melted, and the edge portion was smoothed. Then, it was washed with water by spraying. (F) An aqueous solution of 15 wt% sulfuric acid (containing 0.5 wt% of aluminum ions) at a liquid temperature of 35 ° C. using a DC voltage, a current density of 2 A / dm ² and an anodized film amount of 2.4 g.
/ M ² . Thereafter, water washing by spraying was performed. When the surface of the treated aluminum plate was observed with a Hitachi FESEM,
Large swells of ~ 30 [mu] m, average diameters of 0.5-3.0
μm honeycomb pits were superimposed. Average diameter 0.5
Table 3 shows the area ratio where bits of .about.3.0 .mu.m are generated. The glossiness at 85 degrees was as shown in Table 1. The average surface roughness, surface gradient distribution, and specific surface area determined by AFM were as shown in Table 3. The intermediate layer and the photosensitive layer are applied to this aluminum plate and dried, and the dried film thickness is 2.
A negative PS plate of 0 g / m ² was prepared. When printing was performed using this PS plate, the evaluation results in Table 3 were obtained.

[0072]

[Table 3]

Example 11 Example 10-1 was repeated except that, after the anodic oxidation treatment of (f), the film was immersed in an aqueous solution of sodium silicate.
The surface treatment of the aluminum plate was performed under exactly the same conditions as 10-2 and 10-3. An intermediate layer and a negative photosensitive layer were applied to the treated aluminum plate and dried to prepare a PS plate. When this PS plate was printed, it was a good printing plate.

[0074]

As described above, by carrying out the present invention, it is possible to perform a uniform surface roughening treatment on an aluminum plate without generating processing irregularities due to a difference in the orientation of crystal grains. Become. Further, when the aluminum plate treated according to the present invention is used for a lithographic printing plate support, an excellent printed image can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of an embodiment of an electrolytic polishing apparatus used in the present invention.

FIG. 2 is a schematic diagram of a case where an anodizing treatment and a power supply tank in which an anode is installed are shared in the present invention.

FIG. 3 is an example of a trapezoidal alternating current waveform used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum plate 2 Power supply tank 3 Power supply tank 4 Anode 6 Cathode 7 Power supply 8 Pass roller 9 Nip roller 10, 11 Electrolyte 20 Electrolytic polishing area 30 Anodic polishing area ta Anode reaction time tc Cathode reaction time Ia Anode cycle side current Ic Cathode cycle side current tp Time from current 0 to peak

Claims (15)

[Claims] 1. An indirect power supply system in which an electrolytic reaction tank for performing an anodic reaction on an aluminum plate and an electrolytic reaction tank for performing a cathodic reaction are used as an apparatus used for the electrolytic polishing treatment, and a cathode reaction of the aluminum plate is performed. The same type of electrolyte is used for the power supply tank and the tank for performing the electropolishing treatment by the anodic reaction of the aluminum plate, and at least one of the electrolyte composition, the temperature, and the current density of the power supply tank is changed to the power supply tank. A method for roughening an aluminum plate, wherein the anode is subjected to a cathodic reaction of the aluminum plate in step (1), and the treatment is performed under such conditions that the anode is hardly dissolved. 2. The type of electrolyte or the type and composition of the electrolytic solution in the power supply tank for electrolytic polishing and the power supply tank for anodic oxidation treatment are set to be the same. 3. The method for roughening an aluminum plate according to item 1. 3. The method according to claim 1, wherein an indirect power supply system is used as an apparatus used for the electrolytic polishing treatment, and a power supply tank for anodizing treatment performed in the next step of the electrolytic polishing treatment is used as a power supply tank. The method for roughening an aluminum plate according to the above. 4. An anode comprising lead, platinum or iridium oxide,
Using a lead, carbon, stainless steel, aluminum, titanium, tantalum, niobium, zirconium, hafnium, silver or an alloy thereof as a cathode, an aluminum plate facing each electrode is placed at a current density of 1 to 100 A / dm ² . 1
The method for roughening an aluminum plate according to any one of claims 1 to 3, wherein the electrolytic treatment is performed for 80 seconds. 5. The method for roughening an aluminum plate according to claim 1, wherein the method is performed after mechanical roughening or before or after electrochemical roughening. Roughening method. 6. The step of: (a) mechanically roughening the aluminum plate; (b) electrolytic polishing in an acidic aqueous solution; and (c) performing anodizing in the acidic aqueous solution. A method for roughening an aluminum plate, wherein the treatment is the surface roughening method according to claim 1. 7. An aluminum plate is sequentially treated as follows: (a) mechanical surface roughening treatment; (b) electrolytic polishing treatment in an acidic aqueous solution; or etching treatment in an acid or alkali aqueous solution. (D) electrolytic polishing treatment in an acidic aqueous solution, or etching treatment in an acid or alkali aqueous solution, and (e) anodizing treatment. A method for roughening an aluminum plate, wherein the electropolishing treatment in an acidic aqueous solution is the surface roughening method according to claim 1. 8. An aluminum plate is sequentially subjected to (a) electrolytic polishing treatment in an acidic aqueous solution, or etching treatment in an acid or alkali aqueous solution, and (b) electrochemical treatment using a direct current in an aqueous solution mainly composed of nitric acid. Rough surface treatment (c) Electropolishing treatment in acidic aqueous solution or etching treatment in acid or alkali aqueous solution (d) Electrochemical treatment using DC or AC in aqueous solution mainly composed of nitric acid (E) electrolytic polishing in an acidic aqueous solution, or etching in an acidic or alkaline aqueous solution (f) anodizing treatment, the electrolytic polishing in the acidic aqueous solution is required. Item 4. A method for roughening an aluminum plate, which is the method for roughening an aluminum plate according to Item 1. 9. A desmut treatment is performed after an electrolytic polishing treatment in an acidic aqueous solution or an etching treatment in an acid or alkali aqueous solution.
8. The method for roughening an aluminum plate according to any one of 8 above. 10. An aqueous solution used for an electropolishing treatment,
pH 3 or less, concentration 1 to 90 wt%, and liquid temperature 1
The method for roughening an aluminum plate according to any one of claims 1 to 9, wherein an aqueous solution mainly containing sulfuric acid or phosphoric acid at 0 to 90 ° C is used. 11. The method for roughening an aluminum plate according to claim 1, wherein the amount of dissolution of the aluminum plate in the electrolytic polishing step is 0.05 to 30 g / m ² . 12. The roughening of an aluminum plate according to claim 1, wherein an aluminum plate is used which causes processing unevenness due to a difference in orientation of crystal grains when chemically etched. Surface method. 13. An aluminum plate from which intermediate annealing before cold rolling is omitted is used.
The method for roughening an aluminum plate according to any one of claims 12 to 12. 14. The method for roughening an aluminum plate according to claim 1, wherein an aluminum plate manufactured by continuous casting is used. 15. The aluminum plate for a lithographic printing plate support produced by the method according to claim 1, wherein the physical properties of the surface are in the following ranges. (1) The surface shape defined using the value measured by AFM (atomic force microscope) is in the following range. Using an atomic force microscope (AFM) with a resolution of 0.1 μm in the horizontal (X, Y) direction, measurement was performed in a measurement range of 100 μm square. When the value of a / b (specific surface area) is 1.
15 to 1.5 AF in which the resolution in the horizontal (X, Y) direction is 1.9 μm
AF with an average surface roughness of 0.35 to 1.0 μm measured in a measurement range of 240 μm square using M and a resolution of 1.9 μm in the horizontal (X, Y) direction.
5 to 40% of the rate of inclination of 30 degrees or more measured in a measuring range of 240 μm square using M (2) 85 degree glossiness specified by JIS is 30 or less. (3) When observed at a magnification of 750 with a scanning electron microscope, the average diameter is 0.5 to 20 μm in a field of view of 80 μm.
30% to 100% area of honeycomb pit
That.