JP3256105B2 - Aluminum alloy plate for printing plate and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aluminum alloy plate for a printing plate used as a support for a printing plate in offset printing, and a method for producing the same.

[0002]

2. Description of the Related Art In offset printing, an aluminum plate is generally used as a support, and it is necessary to roughen the surface of the support in terms of adhesion to a photosensitive film and water retention in a non-image area. is there.

Conventionally, a mechanical treatment such as a ball polishing method or a brush polishing method has been used as a surface roughening method. Recently, however, hydrochloric acid, an electrolytic solution containing this as a main component, or nitric acid has been mainly used. Using an electrolytic solution as a component, an electrolytic surface roughening method for electrochemically roughening the surface of an aluminum plate as a support, or a combination of the mechanical and electrolytic surface roughening methods Processing methods are mainly used. This is because the rough plate obtained by the electrolytic surface roughening method is suitable for plate making and has excellent printing performance. Further, the electrolytic surface roughening treatment is suitable for a case where the aluminum plate is coiled and subjected to continuous treatment.

[0004] Various aluminum plates have been developed as such aluminum plates suitable for the electrochemical surface roughening treatment (Japanese Patent Application Laid-Open Nos. 58-28874 and 58-22125).
No. 4), it is known that it is necessary to contain predetermined amounts of Fe, Si and Cu.

Further, in an aluminum plate roughened by an electrolytic surface roughening method, the surface unevenness of the surface is made uniform, and a streak structure (streak) on the surface is affected by hot rolling conditions or casting conditions. In order to suppress or reduce the specific coarse intermetallic compound and feather structure or heat by adding a predetermined amount of Fe, Si and Ti to the aluminum ingot and performing casting or hot rolling under appropriate conditions. Technology has been developed to prevent the generation of coarse tissues such as interstitial fibers (Japanese Patent Application Laid-Open No. 62-148295).
issue).

[0006]

However, when the aluminum plate is roughened by the above-mentioned electrolytic surface roughening treatment method, a single electrode or electrolytic cell cannot be used due to the management of the electrolytic solution. The electrodes or electrolytic baths are arranged in multiple stages, and the electrolytic surface roughening treatment is performed while continuously passing the aluminum plate through each stage. Therefore, in the middle of each stage, the electrolytic surface roughening treatment for the aluminum plate is interrupted. As described above, unlike the case where the electrolytic treatment is continuously performed with a single tank and a single electrode, an unetched portion occurs when the electrolytic treatment is performed in each stage. Even if a material is used, the surface of the aluminum plate may not be uniformly roughened in some cases.

[0007] Recently, it has been required to improve the electrolytic treatment speed in order to reduce the cost. However, even if the aluminum alloy material according to the above-mentioned known technique is used, the surface of the aluminum plate can be made uniform. It may take a considerable time before the surface is roughened.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and is intended to form uniform pits on the surface of a multi-stage process, even in the case of a surface roughening process by electrolysis including an interruption in the middle. An object of the present invention is to provide an aluminum alloy plate for a printing plate and a method for producing the same, which can reduce the time required for electrolytic treatment.

[0009]

The aluminum alloy plate for a printing plate according to the present invention comprises Fe: 0.25 to 0.6% by weight, Si: 0.03 to 0.1% by weight, Cu: 0.05.
% By weight, Ti: 0.05% by weight or less, and Zn: 0.1% by weight.
An aluminum alloy containing 0.1 to 0.10% by weight, with the balance being Al and inevitable impurities,
The relationship between the contents of Ti and Zn is Zn / 2 + Ti-Cu
≧ 0.003% by weight.

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 0.6% by weight,
i: 0.03 to 0.1% by weight, Cu: 0.05% by weight
Hereinafter, a composition containing 0.05% by weight or less of Ti and 0.01 to 0.10% by weight of Zn, with the balance being Al and unavoidable impurities, and the relationship between the contents of Cu, Ti, and Zn Is Zn / 2 + Ti-Cu ≧ 0.003% by weight
500 to 600
Homogenization treatment at a temperature of 400 ° C., after which the starting temperature is 400
After hot rolling at a temperature of from 450 ° C. to 450 ° C., cold rolling is performed, and further, intermediate annealing is performed, followed by cold rolling.

[0011]

The inventors of the present invention have found that aluminum alloy plates for printing plates can form uniform pits and reduce the time required for electrolytic treatment even in electrolytic surface roughening treatment including interruption. Various experimental studies were conducted to develop. As a result, it was found that the surface roughening by electrolysis is greatly affected by the composition of the aluminum alloy plate, the manufacturing process thereof, and the oxide film (passive film) formed during electrolysis.

In particular, by adding a small amount of Zn within the range of impurities to an aluminum alloy containing predetermined amounts of Fe, Si, Cu and Ti, the formation of a passive film on the surface of the alloy plate is suppressed, The pits formed by the electrolysis can be formed uniformly, and the time required for the electrolysis can be shortened.Also, in the manufacturing process of the aluminum alloy sheet, the conditions of the homogenization and the hot rolling are limited. Pits can be formed uniformly.

In order to form the pits uniformly, the weight of the passivation film formed on the surface of the alloy plate must be 0.4%.
g / m ² or less, and the impedance during electrolysis is 10.5
It is preferable to be Ω · cm ² or less.

The reasons for adding the components of the aluminum alloy sheet and the reasons for limiting the composition and the manufacturing conditions in the manufacturing process of the aluminum alloy sheet will be described below.

Fe (iron): 0.25 to 0.6% by weight Fe is an element that combines with other elements in an aluminum alloy to form an Al-Fe eutectic compound.
By adding Fe, recrystallized grains can be refined and a uniform electrolytic roughened surface can be formed. However, when the addition amount of Fe is less than 0.25% by weight, the formation rate of pits which is a reaction starting point when roughening is slow, and it takes a long time to uniformly roughen the surface by electrolysis. It costs. On the other hand, if Fe is added in excess of 0.6% by weight, a coarse compound is formed, and the roughened surface becomes non-uniform. Therefore, the added amount of Fe is set to 0.25 to 0.6% by weight.

Si (silicon): 0.03 to 0.1 weight
The amount% Si forms an Al-Fe-Si based intermetallic compound, which acts as a nucleus for recrystallization between hot passes, and can make recrystallized grains fine during hot rolling. However, if the added amount of Si is less than 0.03% by weight, recrystallized grains cannot be refined, and a large amount of streaks will occur. On the other hand, when Si is added in excess of 0.1% by weight, a coarse compound is formed, and the roughened surface becomes non-uniform. Therefore, the addition amount of Si is set to 0.03 to 0.1% by weight.

Cu (copper): 0.05% by weight or less Cu exists as a solid solution in an aluminum alloy plate,
Adjust the potential of the aluminum matrix and the intermetallic compound. By adding Cu, the resistance in the early stage of the electrolysis can be suppressed, but if it exceeds 0.05% by weight, the formation amount of the passivation film increases, so that the electrolysis resistance increases. . For this reason, coarse pits are formed and the surface becomes uneven. Therefore, Cu
Is 0.05% by weight or less.

Ti (titanium): 0.05% by weight or less Ti is an element for refining crystal grains in an aluminum alloy. However, if the added amount of Ti exceeds 0.05% by weight, a coarse compound is formed, and the roughened surface becomes uneven. Therefore, the addition amount of Ti is set to 0.05% by weight or less. In this case, it is preferable to add a Ti-B master alloy as a crystal grain refiner.

Zn (zinc): 0.01 to 0.10 weight
% Usually, when the aluminum alloy plate is roughened by electrolytic graining treatment method, and generate nonuniform passive film, resistance of the electrolyte is being or increased, pits in the surface of the alloy plate It is formed. However, by adding a small amount of Zn within the range of impurities, the formation of a passivation film can be suppressed, pits formed by electrolysis can be formed uniformly, and the resistance of electrolysis can be suppressed.

If the amount of Zn having such an effect is less than 0.01% by weight, the effect of suppressing the formation of a passivation film is small, and if Zn exceeds 0.10% by weight, A coarse intermetallic compound is generated, coarse pits are formed during etching, and the surface becomes uneven. Therefore, the addition amount of Zn is set to 0.01 to 0.10% by weight.

Zn / 2 + Ti—Cu ≧ 0.003% by weight As described above, in the electrolytic surface roughening treatment method, a non-uniform passivation film is formed or the resistance of electrolysis is increased while the alloy plate is being formed. Pits are formed on the surface of the alloy, but the present inventors have found that the relationship between the amount of Cu added to promote the formation of the passivation film and the amount of Zn and Ti added to suppress the formation of the passivation film is Zn / 2 + Ti−.
It has been found that it is necessary to satisfy Cu ≧ 0.003. If the value of Zn / 2 + Ti-Cu is less than 0.003, the formation amount of the passivation film increases, and the resistance of electrolysis increases. For this reason, coarse pits are formed at the time of etching, and the surface becomes uneven. Therefore, Z
The relationship between the added amounts of n, Ti and Cu is Zn / 2 + Ti−
It is necessary to satisfy Cu ≧ 0.003% by weight.

Next, the reason for limiting the homogenizing treatment temperature and the hot rolling start temperature in the manufacturing process of the aluminum alloy sheet will be described.

Homogenization temperature: 500 to 600 ° C. When an aluminum alloy plate is manufactured from an aluminum alloy ingot by rolling or the like, it is necessary to perform homogenization at a predetermined temperature before rolling. If this temperature is lower than 500 ° C., it cannot be homogenized sufficiently, while
When the homogenization treatment is performed at a temperature exceeding 0 ° C., the crystal grains and the macrostructure become coarse, and a large amount of streaks is generated. Therefore, the homogenization temperature is set to 500 to 600 ° C.

Hot rolling start temperature: 400 to 450 ° C. When hot rolling is performed after the above-mentioned homogenization treatment, it is necessary to start rolling at a predetermined temperature. If the starting temperature is lower than 400 ° C., the macrostructure becomes uneven, and the roughened surface becomes uneven. On the other hand, when hot rolling is started at a temperature exceeding 450 ° C., a large amount of streaks are generated because crystal grains grow in the hot pass. Therefore, the starting temperature of hot rolling is 400 to 450.
° C. In the case of performing the rolling treatment, the homogenizing treatment may be followed by cooling to a temperature within the range of the hot rolling start temperature and rolling. Rolling may be performed by heating.

[0025]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples that fall outside the scope of the claims of the present invention. First, an aluminum alloy ingot having a component composition shown in Table 1 below was face-polished to a thickness of 470 mm, and subjected to a homogenization treatment at a temperature of 590 ° C. for 4 hours. Thereafter, the temperature at the start of rolling was set to 430 ° C., followed by hot rolling, followed by cold rolling. Then, after the intermediate annealing, cold rolling was performed to produce an aluminum alloy plate having a thickness of 0.3 mm. In Table 1 below, values outside the scope of the claims of the present invention are underlined.

[0026]

[Table 1]

Next, degreasing 1, neutralization cleaning 1, AC electrolytic surface roughening treatment, degreasing 2, and neutralization cleaning were performed on each aluminum alloy plate manufactured as described above under the processing conditions shown in Table 2 below. 2 was applied in order. After washing and drying each aluminum alloy plate, a predetermined size was cut out and used as a test material.

[0028]

[Table 2]

With respect to the test material manufactured as described above, the impedance and the weight of the film were measured, and the unetched portion and uniformity of the surface of the test material were evaluated. That is, when the impedance and the weight of the film are equal to or less than the predetermined values, the time required for the electrolytic treatment can be shortened, and when the unetched portion is small and the uniformity is good, over the entire surface of the test material. It can be determined that the roughening has been successfully performed.

The conditions for measuring the impedance and the weight of the film, and the evaluation criteria for the etched portion and the uniformity will be described below.

Conditions for Measuring Impedance In the measurement of impedance, first, the test material was subjected to degreasing and neutralization cleaning in order under the processing conditions shown in Table 3 below.

[0032]

[Table 3]

Thereafter, alternating current electrolysis was performed under the conditions shown in Table 4 below, and the current and potential change with respect to the reference electrode (SCE) were measured at intervals of 0.2 μsec for each cycle. Then, the impedance in consideration of the phase difference was calculated based on the current and potential change at the 600th cycle.

[0034]

[Table 4]

Measurement Conditions for Film Weight In the measurement of the film weight, first, the test material was subjected to degreasing, neutralization washing 1, AC electrolytic surface roughening treatment, and neutralization washing 2 in order under the processing conditions shown in Table 5 below. went.

[0036]

[Table 5]

After the neutralization washing 2 shown in Table 5 above was performed, the weight of the test material was measured. The measured value at this time is defined as weight 1. Thereafter, the test materials were immersed in a mixed solution of phosphoric acid and chromic acid at a temperature of 90 ° C. for 2 minutes, washed and dried, and the weight of each test material was measured. The measured value at this time is defined as weight 2, and the weight of the coating is from weight 1 to weight 2
Was subtracted.

Evaluation Criteria for Unetched Area The surface of the roughened test material was scanned with a scanning electron microscope (hereinafter referred to as “S
EM ”), and micrographs were taken so that the total area of the image was 0.02 mm ² . The SEM magnification was 350 times. Based on this photograph, the area of the unroughened portion was determined, and the unetched rate was calculated by the following equation (1).

[0039]

## EQU1 ## Unetched rate (%) = area of unroughened portion / total area × 100 The unetched portion was evaluated based on the unetched rate calculated in this manner.
That is, when the non-etching rate is 10.0% or less, excellent,
In the case of more than 10% and less than 20%, it is considered as good, and in the case of more than 20%, it is shown as poor in Table 6 below.

Evaluation Criteria for Uniformity The surface of the roughened test material was observed using an SEM, and a micrograph at a magnification of 500 times was taken. A line having a total of 100 cm was drawn on this photograph, and the size of the pits below the line was measured.

At this time, when the size difference between the smallest pit and the largest pit is 3 μm or less, the uniformity is excellent.
When the thickness is larger than 5 μm and less than 5 μm, the uniformity is good.
If it is larger than μm, the uniformity is determined to be poor, and
○, △, and △, respectively.

Table 6 below shows the results of the measurement and evaluation based on the above-described measurement conditions of the impedance and the film weight, and the evaluation criteria for the unetched portion and the uniformity.

[0043]

[Table 6]

As shown in Table 6 above, Examples Nos. 1-3
Regarding the above, both the impedance and the weight of the film became preferable values, and the electrolytic treatment could be performed in a short time. In addition, as shown in the evaluation of the unetched portion and the evaluation of the uniformity, in Examples No. 1 to No. 3, a good roughened surface was obtained over the whole.

On the other hand, in each of Comparative Examples Nos. 1 and 2, the electrolytic treatment could be performed in a short time, but in Comparative Example No. 1 in which the amount of added Si was small, the uniformity was good, but the unetched portions were not. Was inferior to the examples. In Comparative Example No. 2 in which the amount of added Si was large, the evaluation of the unetched portion was excellent, but the surface was extremely non-uniform as compared with the example.

In each of Comparative Examples Nos. 3 and 4, the electrolysis treatment was able to be performed in a short time, but Comparative Example No. 3 in which the amount of Fe added was small had good uniformity.
The evaluation of the unetched part was inferior to the example. In Comparative Example No. 4 in which the amount of Fe added was large, the evaluation of the unetched portion was excellent, but the surface was extremely non-uniform as compared with the example.

In Comparative Example No. 5, since the added amount of Cu was large, the weight of the film was increased and the resistance of electrolysis was increased. For this reason, a long time was required for the electrolytic treatment, and coarse pits were formed, and the surface was extremely non-uniform as compared with the example.

In Comparative Example No. 6, since the amount of Zn added was small, the effect of suppressing the formation of a passive film was small.
As the weight of the film increased, the resistance of electrolysis increased. In Comparative Example No. 7, since the amount of Zn added was large, coarse pits were formed during electrolysis, and the surface became extremely non-uniform as compared with the example.

In Comparative Example No. 8, although the electrolytic treatment could be performed in a short time, a large amount of Ti was added, so that a coarse compound was formed and the surface was extremely non-uniform as compared with the example.

For Comparative Examples 9 to 11, Zn, T
Since the addition amounts of i and Cu did not satisfy the predetermined relationship, the formation amount of the passivation film increased, and the resistance of electrolysis increased. In addition, sufficient etching by the electrolytic treatment was not performed, and the surface became non-uniform as compared with the example.

Next, as a second embodiment of the present invention, a case where a predetermined aluminum alloy ingot is subjected to a homogenizing treatment, a rolling treatment and the like to produce an aluminum alloy plate for a printing plate will be described. First, an aluminum alloy ingot having a component composition of Nos.
mm, and subjected to a homogenization treatment and hot rolling under the temperature conditions shown in Table 7 below. And after hot rolling,
Cold rolling, intermediate annealing, and final cold rolling were performed to produce an aluminum alloy plate having a thickness of 0.3 mm. In Table 7 below, values outside the scope of the claims of the present invention are underlined.

[0052]

[Table 7]

Next, degreasing 1, neutralization cleaning 1, alternating current electrolytic surface roughening treatment, degreasing 2, and neutralization cleaning were performed on each aluminum alloy plate manufactured as described above under the processing conditions shown in Table 2 above. 2 was applied in order. After washing and drying each aluminum alloy plate, a predetermined size was cut out and used as a test material. In the AC electrolytic surface roughening treatment, 2
After electrolysis for 0 seconds, electrolysis was performed again for 20 seconds with a pause of 20 seconds.

With respect to each of the test materials manufactured as described above, the streak, the unetched portion and the uniformity of the surface were evaluated. Hereinafter, the evaluation criteria of the streak will be described. The evaluation criteria for the unetched portion and the uniformity are the same as the evaluation criteria in the first embodiment.

Streak Evaluation Criteria In the evaluation of streak, two test materials having sizes of 15 cm and 10 cm in the rolling direction and the direction perpendicular to the rolling direction were prepared. Therefore, the area is 15cm × 10c
m × 2 sheets = 0.03 m ² . The surface of this test material is subjected to chemical etching (macro etching) with aqua regia, and the case where the length of the streak in the rolling direction is less than 0.5 cm is excellent.
In the case where it is 0.5 cm or more and less than 1 cm, it is good, and when it is 1 cm or more, it is bad.
Indicated by “O” and “X”.

[0056]

[Table 8]

As shown in Table 8 above, Examples Nos. 4 to 6
In each case, good results were obtained in the evaluation of streaks, the evaluation of unetched portions, and the evaluation of uniformity.

On the other hand, for Comparative Examples Nos. 12 to 15,
In each case, the evaluation of the unetched portion and the evaluation of the uniformity were good, but in the evaluation of the streak, the results were all poor.

[0059]

As described above, according to the present invention,
When the aluminum alloy plate is made to have a predetermined component composition and the aluminum alloy plate is manufactured under a predetermined heat treatment condition, uniform pits are formed on the surface of the aluminum alloy plate when the surface is roughened by electrolysis. Thus, an aluminum alloy plate for a printing plate having a favorable roughened surface can be manufactured. In addition, the formation of a passivation film on the surface of the aluminum alloy plate can be suppressed, and the impedance during electrolysis can be suppressed, so that the time required for the electrolysis can be reduced.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-210144 (JP, A) JP-A-63-143234 (JP, A) JP-A-53-11603 (JP, A) 177529 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C22C 21/00-21/18

Claims (2)

(57) [Claims] 1. Fe: 0.25 to 0.6% by weight, S
i: 0.03 to 0.1% by weight, Cu: 0.05% by weight
Hereinafter, an aluminum alloy containing 0.05% by weight or less of Ti and 0.01 to 0.10% by weight of Zn, and the balance being Al and unavoidable impurities. The relationship is Zn / 2 + Ti-Cu ≧ 0.
An aluminum alloy plate for a printing plate, characterized by satisfying 003% by weight. 2. Fe: 0.25 to 0.6% by weight, S
i: 0.03 to 0.1% by weight, Cu: 0.05% by weight
Hereinafter, a composition containing 0.05% by weight or less of Ti and 0.01 to 0.10% by weight of Zn, with the balance being Al and unavoidable impurities, and the relationship between the contents of Cu, Ti, and Zn Is Zn / 2 + Ti-Cu ≧ 0.003% by weight
500 to 600
Homogenization treatment at a temperature of 400 ° C., after which the starting temperature is 400
A method for producing an aluminum alloy plate for a printing plate, comprising: performing cold rolling after hot rolling at a temperature of from 450 ° C. to 450 ° C .;