JP2778667B2 - Aluminum alloy plate for printing plate and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy plate for a printing plate used as a support for offset printing or the like, and in particular, to form a uniform electrolytically roughened surface by a short electrolytic roughening treatment. The present invention relates to an aluminum alloy plate for a printing plate and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, in offset printing, an aluminum or aluminum alloy (hereinafter referred to as aluminum) plate is generally used as a support. This aluminum plate for a printing plate is obtained by subjecting the surface of an aluminum plate to a surface roughening treatment in order to impart adhesion to a photosensitive film and water retention of a non-image portion. Conventionally, mechanical treatment methods such as a ball polishing method and a brush polishing method have been used as the surface roughening method. Recently, however, hydrochloric acid or an electrolytic solution mainly containing hydrochloric acid, or nitric acid or nitric acid has been mainly used. Electrolytic surface roughening method for electrochemically roughening the surface of an aluminum plate using an electrolytic solution to be treated, and furthermore, a method combining the aforementioned mechanical treatment method and this electrolytic surface roughening method. Is being used. This is because the rough surface plate obtained by the electrolytic surface roughening method is suitable for plate making and also has excellent printing performance.In the electrolytic surface roughening method, the aluminum alloy plate is formed into a coil shape. This is because it is suitable for continuous processing.

As described above, it is required that the surface of the aluminum alloy plate to be roughened be formed with uniform irregularities (pits) by the roughening treatment. In an aluminum alloy plate for a printing plate on which uniform irregularities are formed,
Adhesion with the photosensitive film and water retention are improved, and excellent image clarity and printing durability can be obtained. In recent years, in order to reduce the cost of the surface roughening treatment, there is a strong demand for the development of an aluminum alloy plate capable of forming uniform irregularities in a shorter time or with a smaller amount of electricity.

An aluminum alloy plate suitable for such electrochemical surface roughening treatment can be obtained by adding Fe, Cu and other trace elements.
e: 0.2 to 1.0% by weight, Cu: 0.1 to 2.0
Weight% and 1 selected from Sn, In, Ga and Zn
An aluminum alloy sheet containing 0.05 to 0.1% by weight of at least one element has been proposed (JP-A-58-21).
0144). This aluminum alloy plate is characterized in that a uniform electrolytic rough surface can be obtained.

Further, as an aluminum alloy plate having excellent roughness uniformity, Fe: 0.05 to 0.5% by weight, Mg:
0.1 to 0.9% by weight, Si: 0.2% by weight or less, and Cu: 0.05% by weight or less, and one or more elements selected from the group consisting of Zr, V and Ni. 0.0
An aluminum alloy plate containing 1 to 0.3% by weight and the balance consisting of Al and unavoidable impurities has been proposed (JP-A-62-230946).

Further, as an aluminum alloy plate having good strength and uniformity of pits, Mg: 0.30 to 3% by weight, Fe: 0.15 to 0.50% by weight, Ni: 0.0
05 to 0.30% by weight and Ti: 0.01 to 0.1
0 wt%, Si, Cu, and Mn are each regulated to 0.20 wt% or less, and the balance is Al and the content of each element is 0.10 wt% or less. Has been proposed (JP-A-63-30294).

Further, while forming a uniform rough surface,
As an aluminum alloy plate that prevents contamination of non-image areas and improves tone reproducibility and color tone (brightness) of image areas, F
e: 0.1 to 1.0% by weight, Si: 0.02 to 0.
There has been proposed an aluminum alloy plate containing 15% by weight and an impurity of Cu: 0.003% by weight or less, with the balance being unavoidable impurities other than Al and Cu (Japanese Patent Publication No. 47545/1994).

Furthermore, Fe: 0.1 to 0.5% by weight, Si: 0.03 to 0.30% by weight, Cu: 0.0
01 to 0.03% by weight, Ni: 0.001 to 0.0
3% by weight, Ti: 0.002 to 0.05% by weight and G
a: containing 0.005 to 0.020% by weight, and
An aluminum alloy plate having a total content of a and Ti of 0.010 to 0.050% by weight has been proposed (JP-A-3-177528). In this aluminum alloy plate, streaks and irregular image quality unevenness, which are streak-like unevenness in surface roughness, are improved, and the rough surface is uniform, so that contamination of non-image areas is prevented.

[0009]

However, recently,
In order to reduce the cost, an improvement in the electrolytic processing speed is required, and there is a need for an aluminum plate that can form uniform pits in a short electrolytic surface roughening treatment. That is, even when the electrolytic surface roughening treatment time is short and the amount of electricity is small, uniform independent pits are formed in a short time, and unetched portions (unetched portions of the aluminum plate surface) are formed on the aluminum plate. It is desired that this does not occur. However, the conventional aluminum plate has not satisfied such a demand.

The present invention has been made in view of such a problem, and even if the electrolytic surface roughening treatment is performed for a short time, the roughened pits are uniformly formed on the electrolytic roughened surface, and the pits of the pits are formed. An object of the present invention is to provide an aluminum alloy plate for a printing plate having a substantially constant size and a method for manufacturing the same.

[0011]

The first aluminum alloy plate for a printing plate according to the present invention has an Fe content of 0.20 to 0.6.
Wt%, Si: 0.03 to 0.15 wt%, Ti:
An aluminum alloy plate for a printing plate containing 0.005 to 0.05% by weight and Ni: 0.005 to 0.20% by weight, with the balance being Al and unavoidable impurities. The surface portion from the surface layer to be applied to a depth of 3 μm is characterized by containing 0.05 to 0.2% by weight of Si.

The Ti content is preferably at least 0.010% by weight.

Further, the method for producing an aluminum alloy plate for a printing plate according to the present invention, characterized in that B contains 1 to 50 ppm by weight, comprises the composition according to any one of claims 1 to 3. The aluminum alloy ingot is subjected to a homogenization treatment at a temperature of 500 to 630 ° C., and then a starting temperature of 400 to 45
By subjecting the aluminum alloy sheet to hot rolling at 0 ° C., the Si content in the surface layer portion of the aluminum alloy sheet is increased.

In this case, a cold rolling step and an intermediate annealing step may be provided after the hot rolling step. Further, it may have a leveler correction step.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have made an attempt to obtain an aluminum alloy plate for a printing plate on which uniform roughening pits are formed, even when performing electrolytic surface roughening treatment in a short time. As a result of diligent research, it has been found that, among the alloy elements contained in the aluminum alloy plate, Fe and Si which have been conventionally added.
It has been found that, in addition to appropriately adjusting the content of, it is effective to add appropriate amounts of Ni and Ti. In this case, of the surface layers subjected to the electrolytic roughening treatment of the aluminum alloy plate for a printing plate, 3 mm from the outermost surface in the thickness direction with respect to the outermost surface.
By making the Si content of the surface layer up to a depth of μm equal to or higher than the Si content of the entire aluminum alloy plate, it has been found that the electrolytically roughened surface is formed even more uniformly. It has also been found that by adding B as needed, the aluminum alloy plate can be etched even more uniformly.

By appropriately adjusting the alloy element content of the aluminum alloy sheet and the Si content of its surface layer in this way, even when the electrolytic surface roughening treatment is performed in a short time, the surface having good uniformity can be obtained. Pits can be obtained.

First, the reasons for limiting the composition of the aluminum alloy plate for a printing plate according to claim 1 will be described.

Fe (iron): 0.20 to 0.6% by weight Fe has an action of forming uniform pits on the roughened electrolytic surface. Fe is an element that combines with other elements in an aluminum alloy to form an Al-Fe eutectic compound. This eutectic compound has the effect of reducing the size of recrystallized grains and the effect of forming a uniform electrolytic rough surface. If the Fe content is less than 0.20% by weight, the number of reaction initiation points of the electrolytic surface-roughening pits is insufficient, and an unetched portion is generated. On the other hand, Fe
When the content exceeds 0.6% by weight, the roughened electrolytic surface becomes non-uniform due to the formation of a coarse compound. Therefore, the Fe content is set to 0.20 to 0.6% by weight.

Si (silicon): 0.03 to 0.15 weight
% Si forms an Al-Fe-Si-based intermetallic compound and acts as a nucleus for recrystallization between passes in hot rolling, and thus has an effect of miniaturizing recrystallized grains during hot rolling. . When the Si content is less than 0.03% by weight, this effect is small, and the streak evaluation after the printing plate support is deteriorated. On the other hand, when the Si content exceeds 0.15% by weight, the roughened electrolytic surface becomes non-uniform due to the formation of a coarse compound. Therefore, the Si content is 0.03 to 0.15% by weight.
And

Ni (nickel): 0.005 to 0.2
0% by weight of Ni has the function of making the electrolytic rough surface uniform. Ni is Fe
Binds to other elements in the aluminum alloy as in
-An element that easily forms a Ni-based eutectic compound. Further, since Ni is electrochemically nobler than Fe, uniform independent pits are easily formed. For this reason, by adding Ni, a uniform roughened surface can be obtained by a short-time electrolytic surface roughening treatment.

When the Ni content is less than 0.005% by weight,
Since the effect of shortening the time for breaking the passivation film is small, non-uniformity of etching pits due to insufficient electrolysis occurs. On the other hand, when the Ni content exceeds 0.20% by weight, a coarse compound is formed, and the electrolytic rough surface becomes non-uniform. Therefore, Ni
The content is 0.005 to 0.20% by weight.

Ti (titanium): 0.005 to 0.05
The Ti-B master alloy has a function of refining the ingot structure to refine the crystal grains by weight, preferably 0.01% by weight or more . If the Ti content is less than 0.005% by weight, the grain refinement is insufficient. Also,
Ti has the effect of making the electrolytic rough surface uniform, in addition to the above-described miniaturization effect, similarly to the other components described above. In order to sufficiently obtain this effect, the Ti content is preferably 0.01% by weight or more. If the Ti content is less than 0.01% by weight, the electrolytically roughened surface tends to be non-uniform. On the other hand, if the Ti content exceeds 0.05% by weight, a coarse compound is formed, and deep streaky pits due to the coarse compound are formed, so that the electrolytically roughened surface becomes uneven.
Therefore, the Ti content is 0.005 to 0.05% by weight.
And preferably at least 0.01% by weight.

Next, the Si content of the surface layer from the surface of the aluminum alloy plate for a printing plate to a depth of 3 μm will be described.

S of surface layer of aluminum alloy plate for printing plate
i: 0.05 to 0.2% by weight As described above, Si has an effect of refining recrystallized grains during hot rolling. In addition to this effect, by concentrating Si in the surface layer of the aluminum alloy plate, the electrolytic roughened surface can be made even more uniform. If the Si content of the surface layer from the surface to a depth of 3 μm is less than 0.05% by weight, the amount of surface concentration is insufficient, and the uniformity of the electrolytic rough surface is deteriorated. On the other hand, when the Si content in the surface layer portion exceeds 0.2% by weight, an uneven rough surface due to over-etching is formed. Therefore, the Si content of the surface layer from the outermost surface to a depth of 3 μm is set to 0.05 to 0.2% by weight.

The aluminum alloy plate for a printing plate according to claim 3 contains B in addition to the above-mentioned elements.

B (boron): preferably 1 to 50
The amount ppm Ti-B master alloy as described above acts as a grain refiner. This crystal grain refining action is caused by an increase in the refined nuclei due to an increase in the amount of Ti-B particles due to a decrease in the amount of solute Ti. The present inventors have found that, in addition to this effect, an increase in the number of Ti-B particles has an effect of making the electrolytic rough surface uniform.

If the B content is less than 1 ppm by weight, etching pits tend to be non-uniform due to insufficient electrolysis. On the other hand, when the B content exceeds 50 ppm by weight, a coarse compound is formed, and the coarse compound forms streak-like deep pits, so that the electrolytically roughened surface becomes uneven. Therefore, when B is contained, the content is 1 to 50 ppm by weight.
It is preferable that

In any aluminum alloy plate for a printing plate, Cu, Mn, Z
n, Cr, Mg, etc. are considered, and each is 0.02% by weight.
The following does not adversely affect the effects of the present invention.

In the method for producing an aluminum alloy plate for a printing plate according to the present invention, the aluminum alloy ingot having the above composition is subjected to a homogenization treatment at a temperature of 500 to 630 ° C. Hot rolling is performed at a temperature to obtain an aluminum alloy plate for a printing plate. Since the aluminum alloy plate for a printing plate thus obtained has a high Si content in the surface layer portion, when subjected to electrolytic surface roughening treatment, the unetched portion decreases and the pit size decreases. It will be uniform.

The reason for limiting the numerical values of the homogenization treatment temperature and the hot rolling start temperature in the method for producing an aluminum alloy plate for a printing plate will be described.

Homogenization temperature: 500 to 630 ° C. If the homogenization temperature is lower than 500 ° C., the homogenization of the aluminum alloy ingot becomes insufficient, so that the obtained aluminum alloy sheet is subjected to electrolytic surface roughening. In this case, the roughened electrolytic surface becomes non-uniform. On the other hand, when the homogenization treatment temperature exceeds 630 ° C., the crystal grain size becomes coarse, so that the macrostructure becomes coarse, and streaks, which are streaks, are generated.

Further, by setting the homogenization temperature to an appropriate value, the surface roughness of the electrolytic layer can be made uniform by setting the Si concentration in the surface layer to an appropriate amount. Homogenization temperature is 500 ℃
If it is less than 3 μm, the Si concentration in the surface layer portion having a depth of up to 3 μm from the surface is insufficient, and the uniformity of the electrolytic rough surface is deteriorated. On the other hand, when the homogenization temperature exceeds 630 ° C., 3
In the surface layer portion having a depth of up to μm, the amount of Si concentration becomes excessive, and a non-uniform rough surface due to over-etching is formed. Therefore, the homogenization temperature is set to 500 to 630 ° C.

Hot rolling start temperature: 400 to 450 ° C. When the hot rolling start temperature is less than 400 ° C., the structure becomes non-uniform, and the electrolytically roughened surface of the obtained aluminum alloy plate becomes non-uniform. . On the other hand, the hot rolling start temperature is 450
If the temperature exceeds ℃, crystals grow between each pass of hot rolling,
Streaks occur. Therefore, the hot rolling start temperature is 4
00 to 450 ° C.

The hot rolling may be started after cooling the aluminum alloy ingot to a temperature of 400 to 450 ° C. after the above-mentioned homogenization treatment. May be started after the aluminum alloy ingot having the reduced temperature is again heated to a temperature of 400 to 450 ° C.

After the completion of the hot rolling, the obtained aluminum alloy sheet is subjected to one or more cold rolling steps with intermediate annealing as necessary to obtain a printing plate aluminum alloy sheet having a predetermined thickness. obtain. In this case, a leveler correction step may be further provided.

[0036]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples that depart from the scope of the claims. First,
An example (first example) of the aluminum alloy plate for a printing plate according to claim 1 will be described.

First Example An ingot of each aluminum alloy having the chemical composition shown in Table 1 below (Examples 1-3 and Comparative Examples 1-10) was beveled to a thickness of 480 mm to a thickness of 595 ° C. A homogenization treatment at a temperature of 5 hours, followed by hot rolling at a starting temperature of 425 ° C., followed by cold rolling, intermediate annealing and cold rolling in order, to obtain an aluminum sheet having a thickness of 0.3 mm. An alloy plate was obtained. The Si content of the surface layer from the surface of each of the obtained aluminum alloy plates to a depth of 3 μm was analyzed by glow discharge mass spectrometry (GD-MS).

[0038]

[Table 1]

Next, each of the aluminum alloy plates manufactured as described above was subjected to degreasing and neutralization cleaning under the processing conditions 1 or 2 shown in Table 2 below, and then subjected to AC electrolytic surface roughening treatment. Further, in order to remove oxides and the like formed by electrolysis, desmutting treatment was performed. After the end of this desmutting treatment, each aluminum alloy plate was washed with water and dried, cut out to a predetermined size, and used as a cut plate. Note that 1 dm ^{2 in} Table 2 is 0.01 m ² .

[0040]

[Table 2]

The cut surface of each aluminum alloy plate after a series of roughening treatments was surface-observed with a scanning electron microscope (SEM) at a magnification of 350 times.
A photograph was taken so as to be 2 mm ² . From the obtained photograph, the unetched rate was calculated by the following mathematical formula 1.

[0042]

## EQU1 ## Unetched rate (%) = area of unroughened part / total area × 100

From the result of this calculation, the unetched rate was 8.
The case of 0% or less was evaluated as ○ (good), and the case where the unetched rate exceeded 8.0% was evaluated as x (bad), and the unetched portion was evaluated.

The roughened surface of each cut plate was observed and photographed by using a scanning electron microscope with a magnification of 500 times. The total length is 100
A cm line was drawn and the size (diameter) of the pit below the line was measured. If the difference between the smallest pit and the largest pit is 3 μm or less, the uniformity is ◎ (excellent). If it exceeds 3 μm and 5 μm or less, the uniformity is ○ (good).
A sample larger than the sample was evaluated as having poor uniformity (poor).

Further, each aluminum alloy plate (rolling direction 1)
The surface of 5 cm × 10 cm in the vertical direction of rolling × 2 sheets = 3 dm ² ) was chemically etched with aqua regia to evaluate the length of the streaks. ◎ (streak evaluation: excellent) when the length of the streak pattern in the rolling direction is less than 0.5 cm, ○ (streak evaluation: good) and 1 when the length was 0.5 cm or more and less than 1 cm.
cm or more was evaluated as x (streak evaluation: poor).
Table 3 below shows the evaluation of streaks, unetched portions, and uniformity. In each example and comparative example,
Each evaluation under processing condition 1 and each evaluation under processing condition 2 were the same.

[0046]

[Table 3]

As shown in Table 3 above, in Examples 1 to 3, since the content of each element is within the range specified by the present invention, both the unetched portion evaluation and the uniformity evaluation are good. Met. In particular, in Examples 1 and 2, the Ti content was 0.031 and 0.047% by weight and 0.01 and 0.01% respectively.
Since it was more than 0% by weight, the rough electrolytic surface was further uniformed, and the streak evaluation was extremely good.

On the other hand, in Comparative Example 1, since the Si content was less than the range specified in the present invention, which was 0.01% by weight, the refinement of the crystal grains was insufficient, and the streak was prolonged. In Comparative Example 2, the Si content was 0.19% by weight.
Therefore, a coarse compound was formed and the size of the pits varied.

In Comparative Example 3, the Fe content was 0.1
Because of 6% by weight, pits for electrolytic surface roughening are insufficient.
An unetched portion was formed on the rough electrolytic surface. Further, in Comparative Example 4, since the Fe content was as large as 0.64% by weight, a coarse compound was formed, the pit size was varied, and the uniformity was poor.

In Comparative Example 5, since the Ni content was as small as 0.003% by weight, the time for breaking the passive film could not be sufficiently reduced, and the uniformity was deteriorated. On the other hand, in Comparative Example 6, since the Ni content was as large as 0.233% by weight, a coarse compound was formed and the uniformity was poor.

In Comparative Example 7, since the Ti content was as small as 0.003% by weight, the cast structure was insufficiently refined.
Streaks are longer. On the other hand, in Comparative Example 8, since the Ti content was as large as 0.066% by weight, a coarse compound was formed, the pits became deeper and streaked, and the pit uniformity was poor.

In Comparative Example 9, since the Si content in the surface layer of the aluminum alloy plate was as low as 0.03% by weight, the amount of surface concentration was insufficient, and the uniformity was deteriorated. On the other hand, Comparative Example 10
Then, the Si content of the surface layer of the aluminum alloy plate is
Since it was as large as 0.23% by weight, over-etching was caused, the size of the pits varied, and the uniformity evaluation was poor.

Next, an embodiment (second embodiment) of the aluminum alloy plate for a printing plate according to claim 3 will be described.

Second Example Ingots (Examples 4, 5 and Comparative Examples 11 and 12) of aluminum alloys having the chemical compositions shown in Table 4 below were subjected to facing and homogenization in the same manner as in the first example. Processing, hot rolling, cold rolling, intermediate annealing and cold rolling are sequentially performed to achieve a thickness of 0.3
mm was obtained. The comparative examples 1 to 10 of the first embodiment can be made comparative examples of the second embodiment.

[0055]

[Table 4]

Next, as in the first embodiment, each aluminum alloy plate was degreased under the processing conditions 1 and 2 shown in Table 2 above.
Neutralization washing, AC electrolytic surface roughening treatment and desmutting treatment were performed. After the end of the desmutting treatment, each aluminum alloy plate was washed with water and dried, cut to a predetermined size to obtain a cut plate, and various tests were performed on the cut plate in the same manner as in the first embodiment. The etching part evaluation and the uniformity evaluation were investigated. The results obtained are shown in Table 5 below.

[0057]

[Table 5]

As shown in Table 5 above, in Examples 4 and 5, the content of each element was within the range specified in the present invention, and the B content was contained. The rough surface became uniform, and the streak evaluation was equal to or higher than that of the first embodiment. Further, the uniformity was extremely good.

On the other hand, in Comparative Example 11, the B content was 59 ppm by weight, which was larger than the range specified in the present invention, so that a coarse compound was formed and the uniformity was poor.
In Comparative Example 12, since the B content was 0.4 wt ppm, which was smaller than the range specified in the present invention, none of the streak evaluation, the unetched portion evaluation, and the uniformity evaluation were particularly excellent. .

Next, an example of a method for manufacturing an aluminum alloy plate for a printing plate according to the present invention will be described. Table 1 above
An ingot of an aluminum alloy having the same chemical composition as in Examples 1 to 3 and Examples 4 and 5 in Table 4 above was chamfered to a thickness of 480 mm, and then homogenized under the conditions shown in Table 6 below. The aluminum alloy sheets having a thickness of 0.3 mm (Examples 6 to 10 and Comparative Examples 13 to 16) were subjected to a tempering treatment, hot rolling, cold rolling, intermediate annealing and cold rolling.

The obtained aluminum alloy plate was subjected to AC electrolytic surface roughening treatment under the same conditions as in the first embodiment, and then cut out to obtain a cut plate. The roughened surface of the cut plate was observed at a magnification of 350 times using a scanning electron microscope (SEM), and a photograph was taken so that the area of the visual field was 0.02 mm ² . From this photograph, the non-etching rate was calculated from the above-mentioned formula 2. The case where the unetched rate was 10.0% or less was evaluated as ○ (good), and the case where the unetched rate exceeded 10.0% was evaluated as x (bad), and the unetched portion of each cut plate was evaluated.

Further, the roughened surface was observed at a magnification of 500 times using a scanning electron microscope (SEM), and a photograph was taken. From the obtained photograph, the uniformity was evaluated in the same manner as in the first example. That is, the difference in size between the smallest pit and the largest pit is 3 μm or less: ◎ (excellent);
(Good) Those having a size larger than 5 μm were evaluated as having poor uniformity (poor).

The aluminum alloy plate obtained as described above (rolling direction 15 cm × rolling vertical direction 10 cm × 2)
(3 dm ² ) was chemically etched with aqua regia to evaluate the streak length. The case where the length of the stripe pattern in the rolling direction was less than 1 cm was evaluated as ○ (streak evaluation: good) and the case where the length was 1 cm or more was evaluated as x (streak evaluation: poor). Table 6 below shows evaluations for streaks, unetched portions, and uniformity.

[0064]

[Table 6] The chemical compositions 1 to 5 in Table 6 indicate that the chemical compositions are the same as those in Examples 1 to 5 described above.

As shown in Table 6, in Examples 6 to 10, the evaluations for streak, unetched portion and uniformity were all good.

On the other hand, in Comparative Example 13, the homogenization treatment temperature was 488 ° C., which was lower than the temperature specified in the present invention, so that the homogenization was insufficient and the streak evaluation was poor. In Comparative Example 14, since the homogenization treatment temperature was 643 ° C. higher than the temperature specified in the present invention, the crystal grains became coarse, the macrostructure became coarse, and the streak evaluation was poor.

In Comparative Example 15, the hot rolling start temperature was 37
Since the temperature was 6 ° C., which was lower than the temperature specified in the present invention, the structure became non-uniform and the streaks became longer. On the other hand, in Comparative Example 16, since the hot start temperature was 466 ° C., which was higher than the range specified in the present invention, crystals grew between each pass in hot rolling, and streaks occurred.

[0068]

As described above, the aluminum alloy plate for a printing plate according to the present invention not only contains a predetermined chemical component but also has an appropriate amount of Si in the surface layer. In this electrolytic surface roughening treatment, the roughened pits are uniformly distributed on the surface, the size of each pit becomes substantially constant, and the streak becomes shorter.

In the method for producing an aluminum alloy plate for a printing plate according to the present invention, the homogenization treatment temperature and the hot rolling start temperature are appropriate, and the Si content in the surface layer becomes an appropriate amount. It is possible to manufacture an aluminum alloy plate for a printing plate in which uniform roughened pits are obtained later and streak generation is extremely suppressed.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-177528 (JP, A) JP-A-3-122241 (JP, A) JP-A-62-230946 (JP, A) (58) Investigation Field (Int.Cl. ⁶ , DB name) C22C 21/00 B41N 1/08 C22F 1/04

Claims (6)

(57) [Claims] 1. Fe: 0.20 to 0.6% by weight, S
i: a printing plate containing 0.03 to 0.15% by weight, Ti: 0.005 to 0.05% by weight, and Ni: 0.005 to 0.20% by weight, with the balance being Al and unavoidable impurities Aluminum alloy plate for printing plates, characterized in that the surface layer portion from the surface subjected to electrolytic surface roughening treatment to a depth of 3 μm contains 0.05 to 0.2% by weight of Si. Board. 2. The aluminum alloy plate for a printing plate according to claim 1, wherein the Ti content is 0.010% by weight or more. 3. The aluminum alloy plate for a printing plate according to claim 1, further comprising B: 1 to 50 ppm by weight. 4. An aluminum alloy ingot having a composition according to claim 1, wherein the aluminum alloy ingot has a composition of 500 to 63.
The homogenization treatment is performed at a temperature of 0 ° C., and then the starting temperature is 40
A method for producing an aluminum alloy plate for a printing plate, comprising increasing the Si content in the surface layer of the aluminum alloy plate by performing hot rolling at 0 to 450 ° C. 5. The method for producing an aluminum alloy plate for a printing plate according to claim 4, further comprising a cold rolling step and an intermediate annealing step after the hot rolling step. 6. The method for producing an aluminum alloy plate for a printing plate according to claim 5, further comprising a leveler correcting step after the cold rolling step.