JP3256106B2 - Aluminum alloy plate for printing plate and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used for lithographic printing and the like.
The present invention relates to an aluminum alloy plate for a printing plate having excellent uniformity of a roughened surface obtained by electrolytic surface roughening treatment and a method for producing the same.

[0002]

2. Description of the Related Art Generally, aluminum or an aluminum alloy is used as a material for a support in offset printing. In order to improve the adhesion of a photosensitive film to a printing plate and the water retention of a non-image area, a rough surface is used. Is being processed. As the surface roughening method, a mechanical processing method such as a ball polishing method or a brush polishing method, or an electrolytic solution mainly containing hydrochloric acid or nitric acid or an electrolytic solution mainly containing nitric acid is used to electrochemically treat the plate surface. There is an electrolytic surface roughening treatment method for roughening, or a treatment method combining these mechanical treatment methods and the like with an electrolytic surface roughening treatment method. The rough plate obtained by electrolytic surface roughening has high plate making aptitude and printing function, and is suitable for continuous processing of coil materials.

As an aluminum material suitable for such an electrochemical surface roughening treatment, there is an aluminum alloy containing predetermined amounts of Fe, Si and Cu (Japanese Patent Laid-Open No. 58-2).
8874, JP-A-58-221254). In addition, it is necessary to suppress the generation of streaky structures called streaks, which are affected by the uniformity of the electrolytically roughened surface, hot rolling, or casting conditions.
By adding predetermined amounts of e, Si, and Ti, and by appropriately selecting casting conditions and hot rolling conditions, the generation of specific coarse intermetallic compounds and coarse structures such as feather structures or hot fibers are suppressed. The technology is known (JP-A-62-148295).

Further, it is known that by restricting Cu to a predetermined amount or less, tone reproducibility and color tone (brightness) of an image area become good, and printing smear can be prevented. (Japanese Patent Publication No. 1-47545). In recent years, it has been required to improve the electrolytic processing speed in order to reduce the manufacturing cost, and it is necessary to obtain a still shallower pitch uniformly in order to improve the exposure sensitivity of the photosensitive film. ing.

[0005]

However, even when the printing plate material according to the prior art described above is used, an unetched portion may be formed or the uniformity of electrolytic surface roughening may be poor. In addition, there is a problem that the processing time required until an electrolytically roughened surface is uniformly obtained becomes long.

The present invention has been made in view of such a problem, and it is possible to obtain shallow uniform pits for improving the exposure sensitivity of a photosensitive film and to shorten the electrolytic processing time. An object of the present invention is to provide an aluminum alloy plate for a printing plate and a method for producing the same.

[0007]

The aluminum alloy plate for a printing plate according to the present invention comprises Fe: 0.25 to 0.60% by weight, Si: 0.03 to 0.10% by weight, Cu: 0.0
03% by weight or less, Ti: 0.05% by weight or less, and P
b: contains 12 to 150 ppm by weight or less, with the balance being A
1 and unavoidable impurities.

The method for producing an aluminum alloy plate for a printing plate according to the present invention is characterized in that Fe: 0.25 to 0.60% by weight,
i: 0.03 to 0.10% by weight, Cu: 0.003% by weight or less, Ti: 0.05% by weight or less, and Pb: 12
To 150 wt ppm or less, with the balance being 500 ingots of aluminum alloy consisting of Al and inevitable impurities.
A step of performing a homogenizing treatment at a temperature of from 400 to 450 ° C and a step of performing hot rolling at a hot rolling start temperature of from 400 to 450 ° C.

After the hot rolling step, the hot rolled sheet may be cold rolled.

[0010]

The inventors of the present invention have conducted intensive experiments and researches to solve the above-mentioned problems. As a result, the oxide film formed during the pre-treatment of the aluminum plate or the electrolytic surface roughening treatment has been found to reduce the uniformity of the roughened pits. It has been found that the influence greatly depends on the composition of the aluminum alloy plate to be used and the degree of the influence changes.

Further, it has been found that when the amount of the passivation film formed in the AC electrolytic surface roughening treatment is small, the uniformity of the surface roughening pits becomes excellent, and the electrolytic treatment time is further shortened. That is, while containing a predetermined amount of Fe, Si, Cu, and Ti, and by appropriately managing the homogenization processing conditions and the rolling processing conditions in the manufacturing process, it is possible to suppress the formation of passivation during the electrolytic surface roughening processing. It is.

The reasons for adding the components of the aluminum alloy sheet and the reasons for limiting the composition in the present invention will be described below.

Fe (iron): 0.25 to 0.60% by weight Fe combines with other elements in an aluminum alloy to form Al—
Al-Fe is an element that forms an Fe-based eutectic compound,
The eutectic compound is effective for making the recrystallized grains finer and effective for forming a uniform electrolytic roughened surface. Fe
If the content is less than 0.25% by weight, the number of reaction initiation points of the electrolytic surface-roughening pits is insufficient, and the time required for uniformizing the electrolytic surface-roughened surface becomes longer. If the Fe content exceeds 0.60% by weight, the electrolytically roughened surface becomes non-uniform due to the formation of a coarse compound. Therefore, the Fe content is 0.25 to 0.60.
% By weight.

Si (silicon): 0.03 to 0.10
% By weight of Si forms an Al-Fe-Si-based intermetallic compound, which acts as a nucleus for recrystallization between hot rolling passes, and thus has a recrystallized grain refinement effect. Si content is 0.0
If the content is less than 3% by weight, the effect is small, and the streak evaluation in the printing plate support product is inferior. Also, S
When the i content exceeds 0.10% by weight, the roughened electrolytic surface becomes non-uniform due to the formation of a coarse compound. For this reason,
The Si content is 0.03 to 0.10% by weight.

Cu (copper): 0.003% by weight or less Cu exists in a solid solution state in an aluminum alloy and has an action of adjusting the potential of an aluminum matrix and an intermetallic compound. Can be reduced. If the Cu content exceeds 0.003% by weight, the reaction resistance increases due to the increase in the amount of the passivation film formed, and the electrolytic etching pit becomes excessive,
The roughened electrolytic surface becomes non-uniform. Therefore, the Cu content is set to 0.003% by weight or less.

Ti (titanium): 0.05% by weight or less Ti-B is generally known to have an effect as a grain refiner. If the Ti content exceeds 0.05% by weight, a coarse compound is formed, and the electrolytically roughened surface becomes non-uniform. Therefore,
The Ti content is 0.05% by weight or less.

Pb: (Pb): 12 to 150 ppm by weight The formation of etching pits in electrochemical surface roughening involves an increase in reaction resistance due to non-uniform formation of a passive film.
In this regard, the addition of a small amount of Pb suppresses the formation of a passivation film, thereby suppressing the formation of non-uniform pits and the increase in reaction resistance. When the Pb content is less than 12 ppm, the effect of suppressing the formation of the passivation film is small. On the other hand, if the Pb content exceeds 150 ppm, the roughened pits are distorted, and the electrolytically roughened surface becomes uneven. Therefore, the Pb content is 12 to 150 ppm by weight.

Next, the reasons for limiting the processing conditions in the method for manufacturing an aluminum alloy sheet according to the present invention will be described.

Homogenization temperature: 500 to 600 ° C. First, the aluminum alloy ingot having the above composition is homogenized. When the homogenization treatment temperature is lower than 500 ° C., the roughened electrolytic surface becomes non-uniform due to insufficient homogenization. On the other hand, when the homogenization temperature exceeds 600 ° C., the crystal grains and the macrostructure become coarse, resulting in poor streak evaluation. Therefore, the homogenization temperature is 500-600 ° C
And

Hot rolling start temperature: 400 to 450 ° C. After homogenization, the aluminum alloy ingot is hot rolled.
In this case, if the hot rolling start temperature is less than 400 ° C., the structure becomes non-uniform, and the electrolytically roughened surface becomes non-uniform. On the other hand, when the hot rolling start temperature exceeds 450 ° C., the streak evaluation is inferior due to crystal grain growth in the hot rolling pass. This hot rolling starts after the ingot is cooled to 400 to 450 ° C. after completion of the homogenization treatment at 500 to 600 ° C. or 400 to 450 ° C. after completion of the homogenization treatment at 500 to 600 ° C. It is possible to start by reheating to ° C.

After the hot rolling, the rolled sheet is further cold-rolled. In this case, it is preferable to perform intermediate annealing during the cold rolling. The conditions for the cold rolling and the intermediate annealing are not particularly limited, but may be ordinary conditions.

[0022]

EXAMPLES Examples of the aluminum alloy for printing according to the present invention will be specifically described below in comparison with comparative examples. The aluminum alloy ingot having the composition shown in Table 1 below was chamfered to a thickness of 470 mm, and after homogenization treatment at 590 ° C. for 4 hours and hot rolling at 430 ° C., cold rolling and intermediate annealing were performed. And then cold rolled to 0.3m
Thus, an aluminum alloy plate having a thickness of m was obtained.

[0023]

[Table 1]

The obtained Al alloy plate was degreased with a 10% by weight aqueous solution of sodium hydroxide at a temperature of 50 ° C. for 30 seconds.
Neutralized washing with 25% by weight of nitric acid at a temperature of 25 ° C. for 30 seconds, and in 2% by weight of nitric acid, a current density of 20 A / dm ^{2 and a} frequency of 60 Hz,
Under alternating current electrolysis conditions at a temperature of 25 ° C., the current and potential change with respect to the reference electrode (SCE) are measured at intervals of 0.2 μs for each cycle. Calculated.

After the neutralization washing, the current density was 20 A / dm ^{2 in 2} % by weight nitric acid, the frequency was 60 Hz, and the temperature was 25.
The surface of each Al alloy plate was subjected to AC electrolytic surface roughening treatment at 10 ° C. for 10 seconds, neutralized and washed with 30% by weight of nitric acid at a temperature of 25 ° C. for 10 seconds, washed with water, and dried. The measured value at this time is defined as weight 1. Thereafter, the aluminum alloy plate was immersed in a mixed solution of phosphoric acid and chromic acid at a temperature of 90 ° C. for 2 minutes, washed with water, and dried, and the weight of each Al alloy plate was measured. The measured value at this time was defined as weight 2, and the value obtained by subtracting weight 2 from weight 1 was defined as the film formation weight. Table 2 shows the results of the impedance and the film formation weight.

[0026]

[Table 2]

After the above-described AC electrolytic surface roughening treatment, before neutralization washing, the surface was degreased with a 10% by weight aqueous solution of sodium hydroxide at a temperature of 40 ° C. for 10 seconds. The roughened surface of this Al alloy plate was scanned with a scanning electron microscope (SEM) for 35 minutes.
Observe the surface at 0x magnification and the visual field area is 0.02mm in total
^A photograph was taken so as to obtain a value of 2, and the unetched rate was determined from the photograph by the method shown in the following formula 1.

[0028]

## EQU1 ## Unetched rate (%) = area of non-roughened part / total area × 100 Further, etching was evaluated from the obtained unetched rate. The results are shown in Table 3 below. However, in the etching evaluation column, 〇 (good) indicates an unetched rate of 0.0 to 1
0.0%, x (defective) means that the unetched rate exceeds 10.0%.

Further, the roughened surface is scanned with a scanning electron microscope (SE).
M) was used to observe the surface at a magnification of 500 times and photographed. In this photo, draw a line with a total length of 100 cm,
Uniformity was evaluated by determining the size difference between the largest pit and the smallest pit below this line. The results are shown in Table 3 below. However, Δ (good) indicates that the difference in pit size is 3 μm or less, and X (bad) indicates that the difference in pit size exceeds 3 μm.

As shown in Tables 1 to 3, Example No. 1
Nos. 3 to 3 are within the scope of the present invention, and Comparative Examples Nos.
1 is a comparative example in which the composition deviated from the present invention and the uniformity evaluation or etching evaluation was poor.

[0031]

[Table 3]

Next, a description will be given of the results of a test on the effect of the manufacturing conditions in the method for manufacturing an aluminum alloy plate for printing according to the present invention. Example No. 1 shown in Table 1 above.
The aluminum alloy ingot having a chemical composition of 1 to 3 is chamfered to a thickness of 470 mm, subjected to homogenization treatment and hot rolling under the conditions of A to G shown in Table 4 below, and subjected to intermediate annealing after cold rolling. Then, cold rolling was performed to obtain a final alloy plate having a thickness of 0.3 mm.

[0033]

[Table 4] The obtained Al alloy plate was evaluated by the same method as the evaluation in Table 3.

The Al alloy plate obtained by the above method (rolling direction 15 cm × rolling vertical direction 10 cm × 2 sheets = 3 sheets)
dm ² ) was subjected to chemical etching (macro etching) with aqua regia to evaluate streak. However, in the streak evaluation column, ○ (good) indicates that the length of the stripe pattern in the rolling direction is 0.5 cm or more, less than 1.0 cm, and × (bad).
Is a case where the length of the stripe pattern in the rolling direction is 1.0 cm or more. Table 4 also shows the results of the streak evaluation, uniformity evaluation and etching evaluation of the Al alloy plate manufactured under the manufacturing conditions shown in Table 4. Example No. A to C are within the scope of the present invention, and Comparative Examples Nos. D to G indicate that the manufacturing conditions were out of the range of the present invention and the streak evaluation was poor.

As is clear from Tables 3 and 4, this embodiment is excellent in etching evaluation, uniformity evaluation and streak evaluation. On the other hand, the comparative example is poor in etching evaluation, uniformity evaluation or streak evaluation.

[0036]

As described in detail above, according to the present invention, F
e: 0.25 to 0.60% by weight, Si: 0.03 to 0.10% by weight, Cu: 0.003% by weight or less, Ti:
0.05% by weight or less, and Pb: 12 to 150% by weight
Since it contains pm, it is possible to obtain an aluminum alloy plate for a printing plate that has excellent uniformity of roughening pits and that can perform electrolytic treatment in a short time.

Further, according to the present invention, it is possible to manufacture an aluminum alloy plate for a printing plate capable of forming a uniform roughened surface by electrolytic treatment in a short time.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-215727 (JP, A) JP-A-1-1622751 (JP, A) JP-A-3-177528 (JP, A) JP-A-53-1982 114059 (JP, A) JP-A-63-288008 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22C 21/00-21/18

Claims (3)

(57) [Claims] 1. Fe: 0.25 to 0.60% by weight, S
i: 0.03 to 0.10% by weight, Cu: 0.003% by weight or less, Ti: 0.05% by weight or less, and Pb: 12
An aluminum alloy plate for a printing plate, characterized in that the aluminum alloy plate contains from 150 to 150 ppm by weight, with the balance being Al and inevitable impurities. 2. Fe: 0.25 to 0.60% by weight, S
i: 0.03 to 0.10% by weight, Cu: 0.003% by weight or less, Ti: 0.05% by weight or less, and Pb: 12
Containing 150 to 150 ppm by weight, with the balance being an aluminum ingot consisting of Al and inevitable impurities, a step of homogenizing at a temperature of 500 to 600 ° C, and a hot rolling start temperature of 400 to 450 ° C. And hot rolling. The method for producing an aluminum alloy plate for a printing plate. 3. The method according to claim 2, wherein the hot-rolled sheet is cold-rolled after the hot-rolling step.