JP2009090600A - Method for manufacturing aluminum plate for printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the electrolytic etchability of a printing plate used as a PS plate. <P>SOLUTION: During the course of cold rolling of an aluminum plate or after the final cold rolling thereof, the aluminum plate is treated with an alkaline or acidic aqueous solution containing Cu at ≥0.1 ppm to thereby impart the Cu to the aluminum plate surface. The Cu concentration of the extreme surface of the aluminum plate after the end of the cold rolling is desirably 0.03 to 0.1% by mass%. The Cu concentration in the inside of the aluminum plate is desirably ≤0.02% by mass%. Satisfactory treatment is performed in the pretreatment to be carried out prior to the electrolytic etching, and in addition, there is the effect that satisfactory etchability can be obtained even in the electrolytic etching. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing an aluminum plate for a printing plate used for lithographic printing, and is subjected to electrolytic etching treatment and used for the above use.

A printing plate aluminum plate used for a lithographic printing plate is subjected to electrolytic etching after hot rolling and cold rolling. The electrolytic etching is performed for the purpose of roughening the surface of the printing plate in order to improve the adhesion of the photosensitive film and the water retention in the non-image area.
Further, the aluminum plate has a surface oxide film grown in the manufacturing process, and the rolling oil used in rolling remains. Since these oxide films and rolling oils impair the uniformity of electrolytic etching properties, cleaning treatment using an acid or alkali solution is performed prior to electrolytic etching for the purpose of removing or degreasing oxide films (for example, patent documents). 1).

By the way, in an aluminum plate that is subjected to electrolytic etching, if a large amount of Cu is contained, coarse pits are easily formed during electrolytic etching, and good etching is not performed. Therefore, in general, an aluminum material in which the amount of Cu is suppressed to 0.02% or less. Is used.
JP 2004-35984 A

  However, when the amount of Cu in the aluminum material is reduced, the degreasing and alkali etching properties that are pretreatments of the printing plate are reduced, and the oxide film present on the aluminum surface is not sufficiently removed, thereby reducing the uniformity of the electrolytic etching treatment. There is a problem that there are cases.

  The present invention has been made in the background of the above circumstances, and the treatment before electrolytic etching is made good, and the formation of coarse pits is suppressed and the pretreatment is made well during electrolytic etching. It aims at providing the manufacturing method of the aluminum plate for printing plates in which electrolytic etching is made uniformly favorable.

  That is, among the methods for producing an aluminum plate for a printing plate of the present invention, the first present invention is an alkaline or acidic aqueous solution containing 0.1 ppm or more of Cu during or after cold rolling of an aluminum plate. And Cu is imparted to the surface of the aluminum plate.

  The method for producing an aluminum plate for a printing plate according to the second aspect of the present invention is characterized in that, in the first aspect of the present invention, after the treatment with the aqueous solution, final cold rolling is further performed at a reduction rate of 20% or more. .

  The method for producing an aluminum plate for a printing plate according to a third aspect of the present invention is the method according to the second aspect of the present invention, wherein after the treatment with the aqueous solution, a heat treatment is performed to heat to 450 ° C. or more before the end of the final cold rolling. Features.

  According to a fourth aspect of the present invention, there is provided the method for producing an aluminum plate for a printing plate according to any one of the first to third aspects, wherein the Cu concentration on the outermost surface of the aluminum plate after the end of the cold rolling is 0. It is characterized by being 03 to 0.1%.

  According to a fifth aspect of the present invention, there is provided the method for producing an aluminum plate for a printing plate according to any one of the first to fourth aspects, wherein the Cu concentration inside the aluminum plate is 0.02% or less by mass%. It is characterized by.

  That is, according to the present invention, Cu is applied to the surface by treating the aluminum plate with an aqueous solution containing 0.1 ppm or more of Cu during the cold rolling. This aluminum plate is well pretreated with Cu of the surface layer during the pretreatment performed after the cold rolling and prior to the electrolytic etching, so that the oxide film and the degreasing are surely performed. In this pretreatment, the outermost surface containing Cu richly is dissolved and removed. When this aluminum plate is subjected to electrolytic etching, the Cu-rich outermost surface is removed, so that the formation of coarse pits due to Cu-rich is avoided and good electrolytic etching is possible.

The reason for the conditions defined in the present invention will be described below.
Cu concentration / treatment liquid: 0.1 ppm or more In the treatment for an aluminum plate during or after cold rolling, if the amount of Cu contained in the aqueous solution is less than 0.1 ppm by mass, Cu is applied to the aluminum plate surface. Cannot be made uniform, and the pretreatment is not performed well. However, when the treatment is performed with an aqueous solution exceeding 50 ppm, the improvement of the Cu application effect is reduced, and Cu is coarsely deposited on the surface of the aluminum material, making uniform application difficult. Therefore, the Cu content should be 50 ppm or less. Is desirable. For the same reason, the lower limit of the amount of Cu contained in the aqueous solution is desirably 0.5 ppm, and the upper limit is more desirably 20 ppm.
The aqueous solution used for the treatment may be either alkaline or acidic. For example, caustic soda, nitric acid, sulfuric acid and the like can be used. Examples of the treatment method include a spray method and an immersion method.
In addition, the said process can also be additionally performed after the last cold rolling.

Final cold rolling: 20% or more When the treatment with the aqueous solution is performed during the cold rolling, it is desirable that the final cold rolling is further performed at a reduction rate of 20% or more after the treatment. This is because Cu applied to the surface can be made uniform by rolling, and if the rolling reduction is less than 20%, the effect of making uniform is insufficient, which is not preferable. More preferably, it is 50% or more.

Heat treatment: 450 ° C. or higher After the treatment with the Cu-containing aqueous solution, it is desirable to perform a heat treatment for heating the aluminum plate to 450 ° C. or higher. The pretreatment effect can be ensured by diffusing Cu adhering to the surface by the heat treatment into the surface layer of the aluminum plate. The heat treatment is desirably performed for 2 seconds or more in a continuous furnace, and desirably performed for 3 minutes or more in a batch furnace.
In addition, you may perform the said heat processing which performs cold rolling after the process by Cu containing aqueous solution, and heats to 450 degreeC or more after that.

Outer surface Cu concentration: 0.03 to 0.1%
If the Cu concentration on the outermost surface of the aluminum material before the pretreatment is less than 0.03% by mass%, the improvement effect on the pretreatment is small. On the other hand, even if it exceeds 0.1%, the improvement in the effect is small. Adverse effects. For this reason, the Cu concentration is determined. For the same reason, it is desirable that the lower limit is 0.06% and the upper limit is 0.08%.
The outermost surface concentration can be shown as the surface layer concentration. In this case, the surface layer can be represented by a depth of 0.03 μm from the surface.

Aluminum material dough Cu concentration: 0.02% or less It is desirable that the aluminum plate subjected to the Cu application treatment has a Cu concentration of 0.02% by mass or less. In the aluminum material containing Cu exceeding 0.02%, the effect of the Cu application treatment is small, and coarse pits are easily formed during electrolytic etching. For the same reason, the Cu concentration of the aluminum material is more preferably 0.005% or less.
Although the other component of this aluminum material is not specifically limited as this invention, For example, Fe: 0.2-0.6%, Si: 0.03-0.10%, Mg: 0.01-0. Examples thereof include 08%, Zn: 0.01 to 0.08%, and the balance of Al and inevitable impurities.

  As described above, according to the method for producing an aluminum plate for a printing plate of the present invention, the aluminum plate is treated with an alkaline or acidic aqueous solution containing 0.1 ppm or more of Cu during or after the cold rolling of the aluminum plate. Since Cu is applied to the surface of the aluminum plate, a good treatment is performed in the pretreatment performed before the electrolytic etching, and a good etching property can be obtained even in the electrolytic etching.

When producing an aluminum alloy sheet according to the present invention, an aluminum alloy having a composition with a Cu content of 0.02% or less is preferably selected. In a normal manufacturing method, after the alloy is melted, homogenization is performed as necessary. The homogenization process can be omitted.
The molten aluminum alloy is made into an aluminum alloy thin plate through a process of hot rolling → cold rolling.

In the present invention, during the cold rolling or after the final cold rolling, the aluminum alloy plate is treated with an alkaline or acidic aqueous solution containing 0.1 ppm or more of Cu to adhere Cu to the surface of the aluminum plate. As the aqueous solution, caustic soda, nitric acid, sulfuric acid and the like are used.
For the aluminum alloy plate, before the end of the final cold rolling, more preferably, a heat treatment to be heated to 450 ° C. or higher is performed in a continuous furnace or a batch furnace, and Cu deposited on the surface of the aluminum plate by the aqueous solution treatment is converted into aluminum. Diffusion to the plate surface layer.

  After performing the aqueous solution treatment described above, the final cold rolling is preferably performed at a rolling reduction of 20% or more. The number of passes at this time is not particularly limited.

The aluminum alloy plate obtained above preferably contains 0.03% to 0.1% of Cu on the outermost surface (surface layer 0.03 μm depth). As described above, the aluminum alloy plate is usually subjected to electrolytic etching prior to the application of the photosensitive agent, and surface cleaning as a pretreatment prior to the etching. The pretreatment is performed for the purpose of removing oil, dirt, etc. adhering to the surface and removing the oxide film as described above. This pretreatment is usually performed by caustic treatment using caustic soda. However, the present invention may include acid treatment, other treatments, or may comprise a treatment that does not include caustic treatment. In short, it is a treatment process that can achieve the above object. I just need it. It should be noted that the solution used for washing, the washing procedure, conditions, and the like are not particularly limited in the present invention, and can be carried out by a conventional method. In addition, the surface may be cleaned by mechanical polishing together with the pretreatment.
In the pretreatment, Cu is adhered to the surface of the aluminum alloy thin plate, and the pretreatment is effectively performed by the Cu. Further, the rich Cu is removed from the outermost surface layer by this pretreatment.

The aluminum alloy plate whose surface has been cleaned is then subjected to electrolytic etching in order to roughen the surface. This electrolytic etching is performed for the purpose of firmly fixing a photosensitive agent described later to the printing plate surface. In the present invention, the conditions for this electrolytic etching are not particularly limited, and can be performed by a conventional method.
In the material of the present invention, the outermost surface is not in a Cu-rich state, and good etching is performed without forming coarse pits.

  Further, in the aluminum alloy plate, an anodized film is usually formed after the roughening treatment for corrosion prevention and wear resistance. This film treatment can be performed by a conventional method, and the present invention is not particularly limited with respect to production conditions and film properties. After forming the anodized film, a desired photosensitizer is applied to the surface. The type of the photosensitive agent is not limited in the present invention, and a known photosensitive agent can be used. Further, an apparatus, a coating method, and a coating amount used for coating the photosensitive agent are appropriately selected. After application of the photosensitive agent, it is supplied as a PS plate.

(Production of materials)
A JIS A 1050 (0.3% Fe-0.05% Si-Cu) based aluminum material having the composition shown in Table 1 (the balance Al) was cast and subjected to homogenization (560 ° C. × 12 hours), followed by heat. Rolling was performed to 6 mm. In the basic process, cold rolling was performed up to 3 mm, and then Cu application treatment was performed. Next, cold rolling was performed up to 2 mm, and heat treatment was performed at 460 ° C. for 20 seconds. Further, cold rolling was performed to a thickness of 0.30 mm. Next, tensile correction was performed and finished to obtain a test material. In the case of other manufacturing methods, it is shown in the remarks column.

(Evaluation method)-Measurement method
Measurement of Cu Concentration Regarding the Cu concentration contained in the aluminum material, the aluminum material before Cu application treatment was measured by cantlet analysis. On the other hand, the Cu concentration after Cu application treatment was depth analyzed by GD-MASS, the average of the Cu strength concentration of the detected surface layer (0.03 μm depth) was determined, and the results are shown in Table 1.
Further, the Cu concentration of the aqueous treatment solution described later was adjusted, and the Cu concentration was measured by in-treatment / ICP analysis, and is shown in Table 1. The addition of Cu was adjusted by adding an aqueous ammonia solution of copper hydroxide in the case of an alkaline solution. In the case of an acidic liquid, it was adjusted by adding copper sulfate.

Pretreatment As pretreatment, 10% NaOH, 30 ° C, 5 seconds etching on the sample material, 5% nitric acid, 25 ° C, 5 seconds neutralized oxide film thickness on the surface of the sample material Was measured. The measurement was performed by counting oxygen with EPMA and comparing it with oxygen counted from a known film thickness and converting it to a thickness. Eleven points were measured every 100 mm from a plate width of 1000 mm. When the maximum thickness was 3 nm or less, ◎, 5 nm or less was judged as ◯, and when there were one or more points exceeding 5 nm, the result was shown in Table 1. It was shown to.

Exchanges 60A / dm ² in an electrolytic etch uniformity 2% hydrochloric acid was applied for 30 seconds, 11 points for each 100 mm from the plate width of 1000mm width 1 mm ² was observed with an electron microscope, coarse exceeding 10μm diameter circle equivalent The case where the total area ratio of pits and unetched portions was 3% or less was judged as ◎, the case where it was 10% or less was judged as ○, and the case where it exceeded 10% was judged as ×, and EG uniformity is shown in Table 1.

  As shown in Table 1, the sample material of the present invention was excellent in both pretreatment properties and electrolytic etching properties. On the other hand, in the comparative example in which the treatment with the Cu-containing aqueous solution was not performed and the comparative example in which the amount of Cu in the Cu-containing aqueous solution was inappropriate, both the pretreatment property and the electrolytic etching property were inferior.

Claims (5)

  An aluminum plate for a printing plate, characterized by being treated with an alkaline or acidic aqueous solution containing 0.1 ppm or more of Cu during or after the cold rolling of the aluminum plate to impart Cu to the surface of the aluminum plate Manufacturing method.   2. The method for producing an aluminum plate for a printing plate according to claim 1, wherein after the treatment with the aqueous solution, final cold rolling is further performed at a reduction rate of 20% or more.   3. The method for producing an aluminum plate for a printing plate according to claim 2, wherein after the treatment with the aqueous solution, a heat treatment is performed by heating to 450 ° C. or more before the end of the final cold rolling.   The aluminum concentration of the printing plate according to any one of claims 1 to 3, wherein the Cu concentration on the outermost surface of the aluminum plate after the cold rolling is 0.03 to 0.1% by mass. Production method.   The method for producing an aluminum plate for a printing plate according to any one of claims 1 to 4, wherein the Cu concentration inside the aluminum plate is 0.02% or less by mass.