JPH10278446A - Manufacture of lithographic printing substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacture of a lithographic printing substrate including an electrolytic surface coarsening treatment which is free from generation of a striped areal irregularity even by using a low costed aluminum material. SOLUTION: In a method for manufacture of a lithographic printing substrate by application of surface coarsening treatment containing electrolytic surface coarsening treatment of aluminum material or aluminum alloy material, anodic oxidation is executed by 0.01-20 C/dm<2> electricity quantity prior to the electrolytic surface coarsening treatment, and the anodic oxidation treatment of 0.01-20 C/dm<2> of electricity quantity per treatment is executed 1-19 times in the middle of the electrolytic surface coarsening treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a lithographic printing plate support, and more particularly to an aluminum or aluminum alloy material obtained by repeating anodizing treatment a predetermined number of times before and during electrolytic surface roughening treatment. The present invention relates to a method for producing a lithographic printing plate support, wherein a surface roughening treatment is performed while adjusting the surface state of the support (hereinafter referred to as an aluminum material).

[0002]

2. Description of the Related Art Conventionally, an aluminum plate has been used as a support for a lithographic printing plate. The surface of the aluminum plate is used to improve the adhesion to a photosensitive layer provided thereon and to be used during printing. Usually, the surface is roughened for the purpose of improving the property of retaining dampening water.

[0003] As a method of roughening an aluminum plate, there are mechanical graining methods such as ball graining and brush graining, and electrochemical graining by passing an alternating current in an acidic electrolyte such as hydrochloric acid or nitric acid. A method of surface treatment, a method of combining these, and the like are known.

[0004] Among these surface roughening methods, an electrolytic surface roughening method has recently attracted attention due to the stability and good controllability of the surface roughening step. This method has the disadvantage that the power supply device is larger than the mechanical surface roughening method, but has a reduced number of incidental facilities and a reduced number of mechanical sliding parts, resulting in a reduced failure stop rate, There are great advantages in industrial production, such as easy control of the process.

In the electrolytic surface roughening method, an aluminum plate having a large average roughness and a uniform rough surface is easily obtained. Conditions for obtaining such a rough surface include a power supply waveform, a current density,
By controlling various conditions such as electrolysis time, electrolyte composition, humidity, and electrolysis conditions, an aluminum rough plate having desired performance can be obtained. The stable range of these electrolysis conditions is extremely narrow, and it has been difficult to perform stable production while adjusting the conditions within certain conditions. However, in recent years, it has become easier due to advances in control devices and sensors.

Methods for adjusting the electrolytically roughened surface include the ratio of the quantity of electricity between the anode and the cathode (JP-A-54-65607), the power supply waveform (JP-A-55-25381), and the unit area. Combination of the amount of electricity per unit (Japanese Patent Laid-Open No. 56-29
No. 699) is known.

[0007]

However, in such a method, when an attempt is made to adjust the roughened surface of the electrolytic solution, the apparatus or equipment must be capable of greatly changing the electrolytic conditions so as to cope with the adjustment. It must be designed. This entails the upsizing of equipment and equipment, equipment costs,
It is not preferable in terms of running cost. For this reason, there is a strong demand for a method for more effectively controlling the electrolytic surface-roughened surface without greatly changing the electrolytic conditions in the electrolytic surface-roughening step, and the present applicant has already disclosed Japanese Patent Application Laid-Open No. 63-307990. Has proposed a technique in which an anodic oxide film is formed on the surface of an aluminum plate before the electrolytic surface roughening treatment and the diameter of the electrolytic pits is increased to obtain a high surface roughness Ra value.

On the other hand, there is an increasing demand for using relatively inexpensive aluminum materials which contain a large amount of impurities or are not heat-treated for the purpose of reducing material costs. However, when such an inexpensive aluminum material is electrolytically roughened, a large number of stripe-like surface quality irregularities occur on its surface due to the influence of the distribution of the intermetallic compound and the crystal structure. In the streak part of this unevenness of surface quality and its surroundings,
The size and density of the pits are different, and further processing is required for use as a lithographic printing plate support, and in some cases, the pits become unusable. It is difficult to completely eliminate such surface quality unevenness even by the above-mentioned technique by the present applicant, and there is a situation where a more effective roughening method is desired.

The present invention has been made in view of such a situation, and includes an electrolytic surface roughening treatment which does not cause streak-like surface quality unevenness even when an inexpensive aluminum material is used. An object of the present invention is to provide a method for producing a lithographic printing plate support.

[0010]

The inventors of the present invention have conducted intensive studies on the above-mentioned problems, and found that the anodic oxidation treatment was carried out before the electrolytic surface roughening treatment and also during the electrolytic surface roughening treatment. The present inventors have found that the surface morphology of the aluminum material after the surface treatment can be adjusted and the surface quality is improved, and the present invention has been completed. That is, the object of the present invention is to provide a method for producing a lithographic printing plate support by performing a surface roughening treatment including an electrolytic surface roughening treatment on an aluminum material according to the present invention. 0.0
Anodizing is performed at 1 to ²⁰ C / dm ² , and the amount of electricity per one time is 0.01 to 20 during the electrolytic graining treatment.
This is achieved by a method for producing a lithographic printing plate support, wherein the anodic oxidation treatment at C / dm ² is performed 1 to 19 times.

According to the manufacturing method of the present invention, the anodic oxidation of a relatively small amount of electricity is repeated a plurality of times during the electrolytic surface roughening treatment in addition to before the electrolytic surface roughening treatment. By performing electrolytic surface roughening while controlling the film formation amount, fine adjustment of the surface roughening of the aluminum material becomes possible, and even with inexpensive aluminum materials, streak-like surface quality unevenness can be effectively reduced. Can be resolved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a lithographic printing plate support of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a flowchart illustrating an embodiment of the method for producing a lithographic printing plate support of the present invention. The production method of the present invention, in the step of producing a lithographic printing plate support,
It is characterized in that the first anodizing treatment is performed prior to the electrolytic surface roughening treatment, and subsequently, the electrolytic surface roughening treatment and the anodizing treatment are repeatedly performed.

The steps before and after that are optional. For example, as shown in the drawing, a mechanical roughening treatment or the like may be applied to an aluminum material, followed by an etching or desmutting treatment. Examples of the mechanical surface roughening treatment include a method using a transfer roll or a roll brush, and a method such as liquid honing, and these can be used in combination in consideration of productivity and the like. Prior to mechanical surface roughening, removal of rolling oil on the aluminum plate surface using a solvent such as trichlene or a surfactant, or cleaning of aluminum using an alkaline etching agent such as sodium hydroxide or potassium hydroxide. The board surface may be exposed. After performing the mechanical surface roughening treatment in this way,
Chemical etching is performed using an alkaline solution such as caustic soda for the purpose of smoothing and equalizing the surface. In addition, when the chemical etching treatment is performed using an alkaline solution, an insoluble residue, that is, a smut is generated on the surface. Therefore, the smut is removed using an acidic solution.

Next, prior to the electrolytic surface-roughening treatment, the first anodizing treatment is performed, and then the electrolytic surface-roughening treatment and the anodizing treatment are repeated. In the manufacturing method of the present invention, there is a correlation between the amount of the anodic oxide film and the surface state of the aluminum plate after the electrolytic surface roughening treatment, and the surface state of the aluminum material is adjusted by adjusting the amount of the anodic oxide film. It is based on the finding that it can be done.

The electrolytic surface roughening treatment can be performed according to a known method. That is, this is performed by immersing an aluminum material in an electrolytic solution composed of an acidic solution such as an aqueous solution of nitric acid or hydrochloric acid, and applying a sinusoidal or trapezoidal alternating current using the aluminum material as an anode. Here, the concentration of the electrolyte is 0.5 to 2.5.
The weight% and the liquid temperature are generally in the range of 20 to 80C. The frequency of the alternating waveform is generally 60 Hz, and the current density is generally about 10 to 200 A / dm ² . Also in the present invention, the electrolytic surface roughening treatment can be performed under these conditions. As the electrolytic cell, a known electrolytic cell such as a vertical type, a flat type, and a radial type can be used. The electrolytic solution passing through the electrolytic cell may be parallel or counter with respect to the progress of the aluminum material. In the method of the present invention for forming an electrolytic surface after forming an anodic oxide film, the pit diameter tends to be larger than when the anodic oxide film is not formed. It is desirable to control the pit diameter by increasing the temperature or current density. However, these adjustments do not require major changes in equipment.

The anodic oxidation treatment is performed by immersing an aluminum material in an acidic solution containing sulfuric acid or phosphoric acid and applying a direct current or an alternating current using the aluminum material as an anode.
The quantity of electricity in the anodizing treatment is 0.01C per time
/ Dm ^{2 to} 20 C / dm ² , preferably 0.1 C / dm 2
Particularly preferred is ^{2 to 5} C / dm ² . That is, in the anodized film weight ^{basis, 8 × 10 -5 ~0.2g / m} 2 are preferred per, particularly preferably ^{8 × 10 -4 ~5 × 10 -2} g / m 2. The current waveform used for this anodization treatment is as follows:
Either an alternating current waveform or a DC current waveform can be used, but a DC current waveform is preferable in consideration of melting of an electrode used as a counter electrode of the aluminum material. As the DC current waveform, a three-phase full-wave rectified waveform, a single-phase full-wave rectified waveform, a continuous DC waveform, an intermittent DC waveform, or the like using a thyristor or a diode may be used. In addition, the number of times of anodizing
2-20 in total including the treatment performed before the electrolytic surface roughening treatment
Times are preferable, and 2 to 5 times are particularly preferable. If the amount is less than this, the adjustment of the roughened surface is insufficient, while if it is performed 20 times or more, the surface is excessively roughened, and the surface quality is deteriorated.
Note that the conditions for each process may be the same or different. Further, it is desirable to perform water washing before and after each treatment.

The post-process after the above-mentioned electrolytic surface roughening and anodic oxidation is optional. For example, as shown in the figure, etching or desmutting is performed after the final electrolytic surface roughening. Thereafter, an anodic oxidation treatment (anodizing) or a sealing treatment (not shown) can be performed. The etching and desmutting processes are the same as those in the previous step. Also, the anodic oxidation treatment here is different from the anodic oxidation treatment before and during the electrolytic surface roughening treatment, and aims to improve the wear resistance of the aluminum material surface subjected to a series of surface roughening treatments. Is what you do. Next, in order to optimize the adhesion to the photosensitive composition, the anodic oxide film is subjected to sealing treatment with steam or hot water.

In the manufacturing method according to the present invention, the shape of the aluminum material to be treated may be any of a plate shape, a sheet shape, and a belt shape (web).

EXAMPLES Next, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. An aluminum alloy plate that has not been heat-treated is brushed with a grain (No. 8 BG x 5).
This was subjected to a mechanical roughening treatment at 250 rpm and a pressing pressure of 6 KW), followed by etching with a 20% aqueous solution of caustic soda at a liquid temperature of 60 ° C. so that the etching amount became 10 g / m ^2, and then 1% nitric acid The smut was removed by treating with an aqueous solution for 10 seconds. The aluminum alloy plate thus treated was subjected to anodic oxidation treatment under the conditions shown in Table 1 before and during electrolytic graining treatment. The electrolytic surface roughening treatment performed after each anodic oxidation treatment is performed using a 2% nitric acid aqueous solution as an electrolytic solution at a liquid temperature of 40 ° C., using an alternating current of 60 Hz, a current density of 20 A / dm ² , and an anode electric quantity of 200 C / Dm ² . This roughened aluminum alloy plate is
Etching amount 1 with caustic soda at a concentration of 20% and liquid temperature of 35 ° C
g / m ^2, and then the concentration is 20
%, And desmutted with an aqueous solution of sulfuric acid at a liquid temperature of 60 ° C. Next, anodizing was performed in a sulfuric acid aqueous solution having a concentration of 10% and a liquid temperature of 30 ° C. to form a 2 g / m ² anodic oxide film. Table 1 shows the evaluation results of the grain shape and the surface quality of the aluminum alloy plate thus treated.

[0020]

[Table 1]

As can be seen from Table 1, in this embodiment in which the anodizing treatment was performed prior to the electrolytic surface roughening treatment and the anodizing treatment was performed 1 to 19 times during the electrolytic surface roughening treatment, Good evaluation results were obtained for both the grain shape and the surface quality.

[0022]

As described above, according to the method for producing a lithographic printing plate support according to the present invention, heat treatment is not performed.
Alternatively, even an aluminum material having many impurities and easily causing streak-like surface quality unevenness can be improved to a more excellent surface quality. Moreover, since the roughened surface can be adjusted mainly by the amount of the anodic oxide film, there is no need to largely change the conditions of the electrolytic surface roughening treatment, and the equipment is not enlarged.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a method for producing a lithographic printing plate support according to the present invention.

Claims (2)

[Claims] In a method for producing a support for a lithographic printing plate by subjecting an aluminum material or an aluminum alloy material to a surface roughening treatment including an electrolytic surface roughening treatment, the amount of electricity is reduced to 0.1 before the electrolytic surface roughening treatment. performs anodized 01~20C / dm ^2, and to make 1-19 times the anodic oxidation processing for the electric amount per the 0.01~20C / dm ² in the middle of the electrolytic surface roughening treatment A method for producing a lithographic printing plate support, which is characterized in that: 2. An anodizing treatment of an aluminum material or an aluminum alloy material in an electrolytic solution containing sulfuric acid or phosphoric acid by passing a direct current or an alternating current using the aluminum material or the aluminum alloy material as an anode. The method for producing a lithographic printing plate support according to claim 1.