JPH09279277A - Aluminum alloy plate for printing plate and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an aluminum alloy plate for a printing plate in which roughened pits are uniformly formed on the electrolytic roughened face and the diameter of the pits is made approximately certain and to provide a method for producing the same. SOLUTION: This aluminum alloy plate for a printing plate has a compsn. contg., by weight, 0.20 to 0.6% Fe, 0.03 to 0.15% Si, 0.005 to 0.05% Ti, 0.005 to 0.20% Ni, and the balance Al with inevitable impurities. The aluminum alloy plate for a printing plate can be obtd. by subjecting an aluminum alloy ingot having the above chemical compsn. to homogenizing treatment at 500 to 630 deg.C and next executing hot rolling in which the starting temp. is regulated to 400 to 450 deg.C. In the case the obtd. aluminum alloy plate for a printing plate is subjected to electrolytic roughening treatment, the polarization resistance in the initial stage 4 of anodic reaction is regulated to 4 to 17Ωcm<2> .

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 more particularly to an aluminum alloy plate for a printing plate capable of forming a uniform electrolytically roughened surface. It relates to the manufacturing method.

[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, an electrolytic solution mainly containing hydrochloric acid or hydrochloric acid or an electrolytic solution mainly containing nitric acid has been used. An electrolytic surface roughening method for electrochemically roughening the surface of an aluminum plate using a liquid, and a processing method combining the above-mentioned mechanical processing method and this electrolytic surface roughening method are mainly used. It is becoming. This is because the rough plate obtained by the electrolytic surface roughening method is suitable for plate making, and also has excellent printing performance,
Further, the electrolytic surface roughening method is suitable for the case where the aluminum alloy plate is coiled and subjected to continuous processing.

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

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 by a high dissolution rate with respect to chemical etching.

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 Cu of 0.003% by weight or less, and the balance of inevitable impurities other than Al and Cu (Japanese Patent Publication No. 1-47545).

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 (also referred to as streaks, hereinafter referred to as streaks), which are streaky irregularities, and irregular image quality irregularities are improved, and the rough surface is uniform. Dirt on the wire 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, it is required that the electrolytic surface roughening treatment time is short, the etching is performed uniformly in a short time, and an unetched portion (an unetched portion of the aluminum plate surface) does not occur in the aluminum plate. However, the conventional aluminum plate has not satisfied such a demand.

The present invention has been made in view of the above problems, and an aluminum alloy plate for a printing plate in which roughening pits are uniformly formed on an electrolytic rough surface and the size of the pits is substantially constant. And its manufacturing method.

[0011]

The aluminum alloy plate for a printing plate according to the present invention comprises Fe: 0.20 to 0.6% by weight, Si: 0.03 to 0.15% by weight, Ti: 0.0
05 to 0.05% by weight and Ni: 0.005 to 0.
An aluminum alloy plate for a printing plate, containing 20% by weight, and the balance being Al and inevitable impurities, characterized by having a polarization resistance of 4 to 17 Ωcm ² during electrolytic surface roughening treatment.

The method for producing an aluminum alloy plate for a printing plate according to the present invention is characterized in that Fe: 0.20 to 0.6% by weight,
i: an aluminum alloy 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 The ingot is subjected to a homogenization treatment at a temperature of 500 to 630 ° C., and then a starting temperature of 400 to 450
It is characterized by producing an aluminum alloy plate having a polarization resistance of 4 to 17 Ωcm ² at the time of electrolytic graining treatment by performing hot rolling at a temperature of ℃.

In this case, after the hot rolling, cold rolling,
Intermediate annealing and final cold rolling may be sequentially performed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted intensive studies to obtain an aluminum alloy plate for a printing plate on which uniform roughened pits are formed. As a result, among the alloy elements contained in the aluminum alloy plate, Fe and Si more 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. It was also found that it is effective to set the polarization resistance during electrolytic surface roughening within a predetermined range.

An AC electrolytic surface roughening method is generally employed for the surface roughening treatment of the printing plate. In this method, the anodes and cathodes alternate. At the cathode,
A passivation film is formed on the surface of the aluminum plate, while at the anode the surface layer dissolves. The film formation reaction at the cathode and the aluminum dissolution reaction at the anode occur cyclically (alternately) at a constant frequency, so that formation of the passive film and its destruction are alternately repeated on the surface of the aluminum plate. This allows
The surface of the aluminum plate is gradually roughened to form irregularities (pits) on the surface of the aluminum plate. In this case, the initial reaction of the anode in each cycle has a great influence on the rough surface morphology, that is, the abundance ratio of the unetched portion and the uniformity of the pit size. From this point of view, as a result of earnest studies by the inventors of the present application, in order to improve the etching property and reduce the unetched portion as much as possible, in order to improve the uniformity of the rough surface by making the pit size constant. Found that it is necessary to define the polarization resistance in each cycle within an appropriate range.

First, the reasons for limiting the chemical composition of the aluminum alloy ingot for a printing plate and the method for producing an aluminum alloy plate for a printing plate according to the present invention will be described.

Fe (iron): 0.2 to 0.6% by weight Fe is a main component of the aluminum alloy, and is an element forming an Al—Fe intermetallic compound in the aluminum alloy. By adding Fe, the recrystallized grains can be made finer, the structure is made uniform, and the mechanical strength is improved. Fe is Al-Fe
A system intermetallic compound is formed and functions as a starting point of initial pits during electrolytic surface roughening. Fe content is 0.
If the content is less than 2% by weight, the initial pits at the time of electrolytic surface roughening become insufficient because the Al-Fe-based intermetallic compound is insufficient. On the other hand, if the Fe content exceeds 0.6% by weight, a coarse compound is formed, and the electrolytically roughened surface becomes non-uniform. Therefore, the Fe content is set to 0.2 to 0.6% by weight.

Si (silicon): 0.03 to 0.15
% By weight of Si forms an Al-Fe-Si-based intermetallic compound to promote formation of initial pits and to improve pit uniformity. If the Si content is less than 0.03% by weight, the intermetallic compound is insufficient, so that the formation of initial pits is insufficient. On the other hand, if the Si content exceeds 0.15% by weight, a coarse compound is formed, and the electrolytically roughened surface becomes non-uniform. Therefore, the Si content is 0.03 to 0.3.
15% by weight.

Ti (titanium): 0.005 to 0.05
% By weight Ti is an element for refining the cast structure. If the Ti content is less than 0.005% by weight, the refining effect becomes insufficient. On the other hand, when the Ti content exceeds 0.05% by weight, T
The micronizing effect due to the i content is saturated, which is wasteful. In addition, a coarse compound is formed, and uneven pits are likely to be generated during the electrolytic surface roughening treatment. Therefore, the Ti content is set to 0.005 to 0.05% by weight.

Ni (nickel): 0.005 to 0.2
0 wt% Ni improves the chemical solubility of the aluminum alloy plate,
It is an element that increases the amount of etching during electrolytic surface roughening.
In addition, Ni is Al-Fe in the aluminum alloy.
-Form a Si-Ni based intermetallic compound. Since this compound has a more noble electrochemical potential than the Al-Fe-Si intermetallic compound, the formation of initial pits during the electrolytic surface roughening is further promoted, and the uniform electrolytic rough surface is formed in a short time. To be formed. Ni content is 0.
If the content is less than 005% by weight, the improvement in chemical solubility is insufficient and the ability to form initial pits is insufficient.
On the other hand, if the Ni content exceeds 0.20% by weight, chemical dissolution is excessively promoted, so that the uniformity of pits on the rough electrolytic surface is impaired. Therefore, the Ni content is
0.005 to 0.2% by weight.

Next, the reason for limiting the numerical value of the polarization resistance during electrolytic surface roughening will be described.

Polarization resistance: 4 to 17 Ωcm ² As described above, the polarization resistance in each cycle has a great influence on the abundance ratio of unetched portions and the uniformity of pit size. When the contained elements such as Fe, Si and Ni are present in the aluminum alloy plate as intermetallic compounds,
Since the potential difference between the intermetallic compound and the aluminum matrix becomes large, the polarization resistance becomes small and the etching property improves. Therefore, no unetched part occurs,
Uniform pits are formed. However, if the polarization resistance becomes too small, the dissolution will be excessively promoted and the entire surface will be easily dissolved, and the uniformity of the pits will be impaired. Therefore, in addition to the above chemical composition, it is necessary to make the polarization resistance appropriate.

When the polarization resistance is less than 4 Ωcm ² , the entire surface is likely to be dissolved as described above, it is difficult to form uniform pits, and the uniformity of the electrolytic rough surface is impaired. On the other hand, when the polarization resistance exceeds 17 Ωcm ² , the etching property becomes insufficient and the unetched portion increases. Therefore,
The polarization resistance is 4 to 17 Ωcm ² .

Although the electrolytic surface roughening treatment is usually carried out for several thousand cycles, the polarization resistance is set to 4 to 17 Ωcm ² for all cycles.

The definition of the polarization resistance in the present invention will be described below. FIG. 1 is a graph showing the relationship between the potential (V) on the horizontal axis and the current density (A / cm ² ) on the vertical axis, showing one cycle (potential-current) in the electrolytic graining treatment. It is a figure showing a curve. The potentials in the figure are saturated calomel electrodes (SCE)
Is the potential when the potential of is 0V. As shown by the arrow in FIG. 1, the potential rises from the maximum anode potential 3 to the maximum cathode potential 2 with the lapse of time, and then decreases to become the maximum anode potential 3 again. Such cycle 5 is repeated a plurality of times, and the potential becomes 0 V twice in one cycle. Among 0V, the one in the process of increasing the potential is the potential 1 at the start of the anode reaction. Cycle 5
Of these, the portion above the potential 1 is the initial stage 4 of the anodic reaction, and the slope in this initial stage 4 of the anodic reaction, that is, the potential divided by the current density is defined as the polarization resistance. In this case, the specific length of the anode reaction initial stage 4 is not particularly limited, but when the frequency of the electrolytic surface roughening treatment is 50 Hz, for example, about 1 mm from the anode reaction start time of each cycle 5. It is the range until the second passes.

When the initial stage of the anodic reaction is unclear, such as when the frequency of electrolytic surface roughening treatment is different, the initial stage of the anodic reaction is ½ of one cycle from the starting point of the anodic reaction.
Defined as 0 hours elapsed. Further, it goes without saying that the cycle 5 shown in FIG. 1 is an example, and the present invention is not limited to this.

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-mentioned composition is homogenized at a temperature of 500 to 630 ° C. and then started at 400 to 450 ° C. Hot rolling is performed at a temperature to obtain an aluminum alloy plate for a printing plate. In this case, after hot rolling, cold rolling, intermediate annealing, and final cold rolling may be sequentially performed. The reasons 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 treatment temperature: 500 to 630 ° C. When an aluminum alloy sheet is produced from an aluminum alloy ingot by rolling or the like, it is necessary to perform homogenization treatment at a predetermined temperature before rolling the ingot. . If the homogenization temperature is less than 500 ° C, the homogenization is insufficient and
Since the polarization resistance becomes too low, the uniformity of the electrolytic rough surface is impaired. On the other hand, when the homogenization treatment temperature exceeds 630 ° C., the aluminum alloy ingot dissolves a large amount of alloy elements, so that the starting points of the initial pits during electrolytic surface roughening decrease and the polarization resistance increases. The etching area increases. Therefore, the homogenization treatment temperature is 500 to 630.
° C.

Hot rolling start temperature: 400 to 450 ° C. After the above homogenizing treatment, the aluminum alloy ingot is hot rolled at a predetermined start temperature. Hot rolling start temperature is 400
If the temperature is lower than 0 ° C, the dynamic recrystallization during rolling is insufficient, the crystal structure of the rolled plate becomes non-uniform, the polarization resistance becomes large, and unetched parts increase and pits become non-uniform. On the other hand, when the hot rolling start temperature exceeds 450 ° C,
During each pass of hot rolling, the crystal grains grow excessively and the polarization resistance becomes too small, so that the uniformity of the electrolytic rough surface is impaired. Therefore, the hot rolling start temperature is set to 400 to 450 ° C.

[0030]

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 the present invention will be described.

First Example Ingots (Examples 1 to 6 and Comparative Examples 1 to 10) of aluminum alloys having the chemical compositions shown in Table 1 below were chamfered to a thickness of 470 mm at 590 ° C. A homogenization treatment is performed at a temperature for 4 hours, and then the starting temperature is set to 430 ° C., hot rolling is performed, and further cold rolling, intermediate annealing, and cold rolling are sequentially performed to obtain an aluminum plate having a thickness of 0.3 mm. An alloy plate was obtained.

[0032]

[Table 1]

Next, each aluminum alloy plate manufactured as described above was degreased and neutralized and washed under any of the processing conditions A to E shown in Table 2 below, and then the AC electrolytic rough surface was obtained. Then, a desmutting treatment was performed to remove oxides and the like formed by electrolysis. After completion of the desmutting treatment, each aluminum alloy plate was washed with water and dried, cut into a certain size, and used as a test material. Under the treatment condition E, as a mechanical treatment, the aluminum alloy plate was polished with a nylon brush using a pumice suspension. In addition, 1 dm ^{2 in} Table 2 is 0.0
It is 1 m ² .

The polarization resistance of each aluminum alloy plate was measured during the AC electrolytic surface roughening treatment under each treatment condition A to E. Current (current density) of each cycle of each electrolytic surface roughening treatment
Further, the potential with respect to the saturated calomel electrode was measured, and the polarization resistance was calculated from the potential-current curve at the first cycle and the potential-current curve at the 500th cycle among the obtained potential-current curves. The obtained polarization resistance under each treatment condition is shown in Table 3 below.

[0035]

[Table 2]

[0036]

[Table 3] The unetched portions and uniformity of each test material were evaluated by the following tests.

Evaluation of Unetched Area The roughened surface of each test material was observed with a scanning electron microscope (SEM) at a magnification of 350 times so that the area of the visual field was 0.02 mm ^2. I took a picture. From the obtained photograph, the unetched rate was calculated by the following mathematical formula 1.

[0038]

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

From this calculation result, 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.

Uniformity Evaluation The roughened surface of each test material was observed with a scanning electron microscope at a magnification of 500, and the surface was observed and photographed. A line having a total length of 100 cm was drawn on the obtained observation photograph, and the size (diameter) of the pit under the line was measured. Those having a difference in size between the smallest pit and the largest pit of 3 μm or less were evaluated as having good uniformity (good) and those having a size larger than 3 μm were evaluated as having poor uniformity (poor).

Table 4 below shows the evaluation of the non-etched portion and the uniformity for each processing condition.

[0042]

[Table 4]

As shown in Table 4, in Examples 1 to 6, the content of each element is within the range specified in the present invention, and each polarization resistance at the 1st and 500th cycles is the present invention. Since it was within the range defined by the above, both the unetched part evaluation and the uniformity evaluation were good.

On the other hand, in Comparative Example 1, since the Ni content of the aluminum alloy plate was 0.004% by weight, which was less than the range specified in the present invention, the ability to form initial pits was not sufficient, and the chemical solubility was low. Was insufficient. For this reason, many unetched parts remain, and the pit size varies, which deteriorates the uniformity.

In Comparative Example 2, Ni of the aluminum alloy plate was used.
The content is as high as 0.3% by weight. Also, processing conditions B and E
The polarization resistance at the 1st cycle in Table ¹ is as small as 3.8 and 3.7 Ωcm ^2, and the polarization resistance at the 500th cycle in the processing conditions B and E is as small as 3.8 and 3.2 Ωcm ² . Due to these factors, the chemical solubility was excessively promoted, resulting in poor uniformity evaluation.

In Comparative Example 3, since the Si content was as high as 0.03% by weight, a coarse compound was formed and the electrolytically roughened surface became non-uniform, resulting in poor uniformity evaluation. In addition, an unetched part has occurred.

In Comparative Example 4, since the Si content was as small as 0.01% by weight, the formation of initial pits was insufficient and the uniformity of pits deteriorated.

In Comparative Example 5, since the Fe content was as small as 0.15% by weight, the Al--Fe intermetallic compound was insufficient, and the initial pits were not sufficiently formed during electrolytic graining. . Further, the polarization resistances at the first cycle under the processing conditions A and E were as large as 17.1 and 17.4 Ωcm ^2, and the polarization resistances at the 500th cycle under the processing conditions A and E were 17.8 and 1, respectively. 17.1 Ωcm
^{It was 2} and big. Due to these factors, an unetched portion is generated. In addition, the uniformity evaluation was poor.

In Comparative Example 6, since the Fe content was as large as 0.70% by weight, a coarse compound was formed. Further, the polarization resistances in the first cycle under the processing conditions B to E are respectively
It is as small as 3.2, 3.8, 3.3, and 3.9 Ωcm ^2, and the polarization resistance at the 500th cycle under the processing conditions B to E is 3.7, 3.5, 3.4, and 3. 9Ω
It is as small as cm ² . Due to these factors, the size of the pits varied, and the uniformity evaluation became poor.

In Comparative Example 7, since the Ti content was as small as 0.003% by weight, the grain refinement was insufficient and the uniformity evaluation was poor.

In Comparative Example 8, since the Ti content was as high as 0.06% by weight, non-uniform pits were formed.

In Comparative Example 9, the polarization resistances in the first cycle under the processing conditions A to E were 3.9, 3.1, and 3.1, respectively.
In addition to being as small as 3.8, 2.8 and 3.6 Ωcm ² , the polarization resistance at the 500th cycle under the processing conditions A to E is 3.2, 3.1, 3.8, 2.9 and 3. 5
Since it is as small as Ωcm ² , the pit size varies, and the uniformity evaluation becomes poor.

In Comparative Example 10, the polarization resistances in the first cycle under the processing conditions A to E were 17.5 and 17.
1, 17.8, 17.1 and 18.0 Ωcm ^2, and the polarization resistance at the 500th cycle under the processing conditions A to E was 17.5, 17.1, 17.2, 1 respectively.
Since it was as large as 7.1 and 18.1 Ωcm ² , the etching property was lowered and an unetched portion was generated. In addition, the size of the pits varied.

Next, an embodiment (second embodiment) of a method for manufacturing an aluminum alloy plate for a printing plate will be described.

Second Example An ingot of each aluminum alloy having the same chemical composition as that of Example 1 shown in Table 1 above was chamfered to have a thickness of 470 mm, and then the temperature conditions shown in Table 5 below. Homogenization treatment, hot rolling, cold rolling, intermediate annealing, and final cold rolling were performed to obtain aluminum alloy sheets having a thickness of 0.3 mm (Examples 7 to 9 and Comparative Examples 11 to 14). .

Next, with respect to each aluminum alloy plate, under any one of the processing conditions A to E shown in Table 2 above,
Degreasing, neutralization cleaning, dipping, AC electrolytic surface-roughening treatment, and desmut treatment were sequentially performed. After the obtained aluminum alloy plate was washed with water and dried, it was cut into a certain size to obtain a test material. The polarization resistance was measured at the 300th cycle of each treatment. The unetched portion and the uniformity were evaluated by the same test method and evaluation criteria as in the first embodiment. However, the case where all of the processing conditions A to E were good was marked with ◯, and the case of any one of the processing conditions A to E was defective and marked with x. The results obtained are shown in Table 5 below.

[0057]

[Table 5]

As shown in Table 5 above, in Examples 7 to 9, the evaluations on the unetched portion and the uniformity were all good.

On the other hand, in Comparative Example 11, the homogenization treatment temperature was 488 ° C., which was lower than the temperature specified in the present invention, so that the polarization resistances under the treatment conditions B, C and D were respectively 3.
It became as small as 7, 3.9 and 3.6 Ωcm ² , and the uniformity evaluation was poor.

In Comparative Example 12, the homogenization treatment temperature was 640.
C. and higher than the temperature specified in the present invention, the polarization resistances under the processing conditions A and E are 17.4 and 1 respectively.
It became as large as 7.3 Ωcm ² and an unetched portion was generated. In addition, the size of the pits varied.

In Comparative Example 13, the hot rolling start temperature was 37.
Since the temperature is 5 ° C., which is lower than the range specified in the present invention, the polarization resistance under the processing condition C is as large as 17.1 Ωcm ² ,
An unetched part has occurred. In addition, the size of the pits varied.

In Comparative Example 14, the hot rolling start temperature was 47.
Since the temperature is 3 ° C., which is higher than the range specified in the present invention, the polarization resistance under the processing condition D is as small as 3.9 Ωcm ² ,
The pit size varied, and the uniformity evaluation became poor.

[0063]

As described above, the aluminum alloy plate for a printing plate according to the present invention, in addition to containing predetermined chemical components, has an appropriate polarization resistance during electrolytic graining treatment. The roughening pits are uniformly formed on the electrolytic rough surface, and the size of each pit becomes substantially constant.

In the method for producing an aluminum alloy plate for a printing plate according to the present invention, an aluminum alloy ingot having a predetermined chemical composition is homogenized and hot-rolled under predetermined conditions. A printing plate aluminum alloy plate having an appropriate polarization resistance can be obtained.

[Brief description of drawings]

FIG. 1 shows the potential (V) on the horizontal axis and the current density (A on the vertical axis).
/ Cm ² ) is a graph showing the relationship between the two, showing one cycle in the electrolytic surface roughening treatment.

[Explanation of symbols] 1; potential at the start of anode reaction 2; maximum cathode potential 3; maximum anode potential 4; initial stage of anode reaction 5; cycle

Claims (3)

[Claims] 1. Fe: 0.20 to 0.6% by weight, S
A printing plate containing i: 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 inevitable impurities. An aluminum alloy plate for a printing plate, which has a polarization resistance of 4 to 17 Ωcm ² during electrolytic graining treatment. 2. Fe: 0.20 to 0.6% by weight, S
i: an aluminum alloy 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 The ingot is subjected to a homogenization treatment at a temperature of 500 to 630 ° C., and then a starting temperature of 400 to 450
A method for producing an aluminum alloy plate for a printing plate, which comprises producing an aluminum alloy plate having a polarization resistance of 4 to 17 Ωcm ² during electrolytic surface roughening by hot rolling at a temperature of ℃. 3. The method for producing an aluminum alloy plate for a printing plate according to claim 2, wherein cold rolling, intermediate annealing and final cold rolling are sequentially performed after the hot rolling.