JP2002322529A - Aluminum alloy plate for printing plate and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy plate for a printing plate which has high electrolytic efficiency, and in which reactivity, the fineness of pits and the uniformity of the roughened face can be improved in electrolytic roughening treatment at a high current density and in a short time, and a production method therefor. SOLUTION: An aluminum alloy ingot having a composition containing, by mass, 0.25 to 0.45% Fe, 0.02 to 0.08% Si and <=0.04% Cu, and the balance Al with inevitable impurities, and in which the content of Ni in the inevitable impurities is controlled to <=0.005% is subjected to homogenizing treatment at >=550 deg.C, and is thereafter hot-rolled at a starting temperature of 400 to 450 deg.C. Subsequently, the plate is subjected to annealing treatment of rising its temperature at the average temperature rising rate of 10 to 60 deg.C/hr for at least one time, and performing holding at 450 to 500 deg.C for 1 to 20 hr, so that the aluminum alloy plate is produced.

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 lithographic printing plate and a method for producing the same. It is about the method.

[0002]

2. Description of the Related Art In general, an aluminum alloy plate for printing is used by roughening the surface by applying a current in a dilute solution of hydrochloric acid or nitric acid. At this time, an aluminum alloy that forms a uniform rough surface with a small amount of electricity is required.

[0003] As a technique for manufacturing an aluminum alloy plate capable of obtaining a highly reactive and uniform roughened surface during electrolytic surface roughening,
Two types of technology have been proposed. First, as a method of achieving a uniform electrolytic rough surface by adjusting the additive element,
For example, those described in JP-A-11-99760 can be mentioned. As a method for achieving a uniform electrolytic roughened surface by adjusting an intermetallic compound of an additional element in an aluminum alloy, for example, Japanese Patent Application Laid-Open No. H11-11533
No. 3 publication.

[0004]

However, recently,
Under the demand of high productivity, as described in Japanese Patent Application Laid-Open No.
/ Dm ² at 3 seconds, as in 85A / dm ² for 6 seconds, began to high current density and electrolytic roughening in a short time are suggested.

Further, with the improvement of the technology of the photosensitive film, there is a demand for an aluminum alloy plate capable of forming finer pits, in other words, forming uniformly dispersed pits.

[0006] However, in the above-mentioned conventional technology for making the electrolytic rough surface uniform, in the electrolytic treatment at a high current density and in a short time,
The reactivity, the fineness of the pits, and the uniformity of the rough surface are all inadequate, and there has been a demand for the development of an aluminum alloy plate that satisfies the characteristics required for recent printing plates and their manufacturing methods. I have.

The present invention has been made in view of the above problems, and has high electrolysis efficiency, high reactivity, fineness of pits and rough surface in a high current density and short time electrolytic surface roughening treatment. An object of the present invention is to provide an aluminum alloy plate for a printing plate capable of improving uniformity and a method for producing the same.

[0008]

The aluminum alloy plate for a printing plate according to the present invention comprises 0.25 to 0.45% by mass of Fe, 0.02 to 0.08% by mass of Si, and 0.04% of Cu.
% Of Al and unavoidable impurities, and the composition is such that Ni in the unavoidable impurities is regulated to 0.005% by mass or less, and the particle size is 1 μm or less.
The amount of the intermetallic compound is 0.02% by mass or more.

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 0.45% by mass,
i: 0.02 to 0.08 mass%, Cu: 0.04 mass%
The aluminum alloy ingot having the following composition, with the balance being Al and inevitable impurities, having a composition in which Ni in the inevitable impurities is regulated to 0.005% by mass or less, is
A step of homogenizing at a temperature of 50 ° C. or higher, a step of hot rolling at a starting temperature of 400 to 450 ° C., and thereafter, heating at least once at an average heating rate of 10 to 60 ° C./hour to 450 Performing an annealing treatment at 1 to 20 hours at a temperature of from 500 to 500 ° C. to produce an aluminum alloy sheet having an Fe intermetallic compound having a particle size of 1 μm or less of 0.02% by mass or more. .

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The inventors of the present application have proposed that F
e) The effect of intermetallic compounds was studied diligently. That is, in the prior art, most of the Fe content is crystallized with a particle diameter of more than 1 μm mainly generated in the casting process, and a small amount of the remaining Fe is dissolved in the aluminum alloy, and the particle diameter is 1 μm or less. The amount of the precipitate (Fe intermetallic compound) was extremely small. The above-mentioned intermetallic compound, which is a crystallized substance having a particle size of more than 1 μm alone, does not have an appropriate existence density (area density).
Therefore, in the present invention, attention is paid to Fe intermetallic compounds having a particle size of 1 μm or less, and by precipitating an intermetallic compound having a particle size of 1 μm or less by a homogenization treatment and an annealing treatment, the distribution thereof is adjusted, and the reactivity and the coarseness are adjusted. A test was performed for surface uniformity.

As a result, it has been found that an Fe intermetallic compound having a particle size of 1 μm or less serves as a pit forming nucleus, and a large number of pits can be formed, so that a uniform surface with a small amount of electricity can be formed. The present invention has been completed based on this finding.

That is, the particle size in the aluminum alloy plate is 1 μm.
m by adjusting the content of the fine Fe intermetallic compound in the aluminum alloy to 0.02 mass% or more,
There are many starting points for pit generation, and fine pits uniformly dispersed with a small amount of electricity can be formed.

In this case, in order to produce such a fine Fe intermetallic compound in a predetermined amount or more, it is desirable to perform casting under the condition that the solid solubility of Fe is as high as possible. Further, the particle size generated in the casting process exceeds 1 μm.
The e intermetallic compound can be once dissolved in an aluminum alloy by a homogenization treatment, and then precipitated as a Fe intermetallic compound having a particle size of 1 μm or less by intermediate annealing. That is, in the homogenization process, the aluminum alloy plate is
Heating to a temperature of 550 ° C. or higher at which the intermetallic compound forms a solid solution makes the Fe-based crystallization finer and increases the amount of Fe solid solution in the aluminum alloy. And, after the end of hot rolling,
By performing annealing, Fe in solid solution is precipitated,
The particle size is changed to an Fe intermetallic compound having a particle size of 1 μm or less.

[0014] Hot rolling is performed and then at least one
Annealing times. The annealing treatment conditions are as follows: the temperature is raised at an average rate of 10 to 60 ° C./hour;
And heating for 1 to 20 hours. Thereby, the content of the Fe intermetallic compound having a particle size of 1 μm or less in the aluminum alloy can be 0.02% by mass or more.

Next, the reasons for limiting the numerical values in the manufacturing method of the present invention will be described.

[Homogenization treatment temperature: 550 ° C. or higher] If the homogenization treatment temperature is lower than 550 ° C., the crystallized substances generated in the casting process cannot be sufficiently refined, and the amount of Fe solid solution increases. I can't let it. Therefore, Fe intermetallic compounds having a particle size of less than 1 μm are reduced.

[Hot rolling start temperature: 400 to 550]
[° C] When the starting temperature of hot rolling exceeds 550 ° C, crystal grains grow excessively. As a result, the roughened surface becomes non-uniform, so the hot rolling start temperature is set to 550 ° C. or less. Also,
When the starting temperature of hot rolling is lower than 400 ° C., dynamic recrystallization during rolling is insufficient, and the uniformity of the rough surface is similarly impaired. Therefore, the hot rolling start temperature is 400 to 550 ° C.
And

[Temperature increase rate: 1 to 60 ° C./hour] If the temperature increase rate is less than 1 ° C./hour, the throughput becomes too long and the production cost increases. On the other hand, the heating rate is 60 ° C. /
If the time is exceeded, the rate of temperature rise is too high, so that the precipitation does not proceed sufficiently and a desired fine Fe intermetallic compound cannot be produced.

[Heat-holding temperature: 450 to 500 ° C.] When the heat-holding temperature is lower than 450 ° C., the proceeding speed of the precipitation is slow and the precipitation is insufficient. In addition, the heating holding temperature is 50
If the temperature exceeds 0 ° C., on the contrary, solid solution proceeds and precipitates decrease.

Next, the reasons for adding the components and the reasons for limiting the composition of the aluminum alloy plate for a printing plate of the present invention will be described.

[Fe: 0.25 to 0.45% by mass] F
e forms an Al-Fe intermetallic compound and has an effect on maintaining mechanical strength by refining recrystallized grains and making the structure uniform. This Fe-based intermetallic compound acts as a starting point of initial pits during electrolytic surface roughening. However, when the Fe content is less than 0.25% by mass, even when all the Fe contained in the aluminum alloy is precipitated as an intermetallic compound, the reactivity in the electrolytic treatment is insufficient and uniform pits are formed. And the strength is low,
Not suitable for use as a printing plate. On the other hand, when the Fe content exceeds 0.45% by mass, the intermetallic compound having a particle size exceeding 1 μm, that is, the crystallized product is not sufficiently reduced regardless of the conditions of the homogenization treatment. For this reason, such coarse crystals serve as starting points for generating coarse pits. Therefore, F
The e content is set to 0.25 to 0.45% by mass.

[Si: 0.02 to 0.08% by mass] S
i forms an Al-Fe-Si-based intermetallic compound and acts as a nucleus for recrystallization between passes during hot rolling, and thus has an effect of miniaturizing recrystallization during hot rolling. Further, the effect of promoting the formation of initial pits and improving the uniformity of pits is achieved. However, when the Si content is 0.1.
When the Si content is less than 02% by mass, the reactivity in the electrolytic treatment is low, and when the Si content exceeds 0.08% by mass, the reactivity in the electrolytic treatment becomes excessive and non-uniform pits are formed.

[Cu: 0.04% by mass or less] Cu affects the uniformity of electrolytic surface roughening, but if the Cu content exceeds 0.04% by mass, uniformly dispersed pits cannot be formed. Therefore, the Cu content is set to 0.04% by mass or less.

The positively added element is as described above. The reason for restricting the content of Ni, which is an unavoidable impurity, is as follows.

[Ni: 0.005% by mass or less] Although Ni improves the etching property of electrolytic surface roughening, if the Ni content exceeds 0.005% by mass, the etching property during electrolytic surface roughening becomes excessive. And it is easily corroded, resulting in printing stains. For this reason, the Ni content is restricted to 0.005% by mass or less.

Since Mn, which is an unavoidable impurity, lowers the etching property of the aluminum alloy and may cause printing stains, its content is preferably limited to 0.05% by mass or less.

[0027]

EXAMPLES The effects of the present invention will be described below with reference to examples of the present invention, as compared with comparative examples that are out of the scope of the present invention. Table 1 below shows the composition of the aluminum alloy plate used and the manufacturing conditions. First, a molten aluminum alloy having the composition shown in Table 1 was cast into an ingot having a thickness of 400 mm. Next, the aluminum alloy sheet was homogenized by heating at a temperature shown in Table 1 for 6 hours, and the starting temperature was set to 450 ° C. to start hot rolling. Hot rolling was completed when the thickness of the aluminum alloy plate reached 3 mm. Then, it cold-rolled until thickness became 1.5 mm, and then performed intermediate annealing under the conditions described in Table 1. After the intermediate annealing, the aluminum alloy sheet was cold-rolled until the thickness became 0.24 mm. The amount of the Fe intermetallic compound in Table 1 is the mass ratio of the Fe-based intermetallic compound having a particle size of 1 μm or less to the entire aluminum alloy.

[0028]

[Table 1]

Next, a description will be given of a test method of the aluminum alloy plate manufactured under the above-described conditions.

[Method for measuring the amount of Fe intermetallic compound deposited]
About 2 g of an aluminum alloy plate was dissolved in phenol heated to 180 ° C. Then, the residue was filtered with a micro filter having a pore size of 1 μm. The filtrate was further filtered through a 0.1 μm pore microfilter. The residue obtained is Al-
Fe-based compound and simple metal Si. The residue was dissolved in hydrochloric acid, and the amount of Fe in the bath was measured by ICP-MS (atomic absorption spectrometry).
e The amount of the intermetallic compound was calculated.

[Method of Measuring Electrolytic Efficiency] An aluminum alloy plate was immersed in a 2% by mass aqueous HCl solution, the temperature of the aqueous HCl solution was adjusted to 25 ° C., and the current density was 80 A / dm.
^2. Energization was performed under the condition that the energization time was 11 seconds to perform electrolytic surface roughening. The mass of the aluminum alloy plate before and after energization was measured, and the difference between them was defined as the dissolution loss. In this case, since the amount of electricity passed is 880 C / dm ² , the theoretical dissolution amount is calculated to be 0.0821 g / dm ² from Faraday's law. Therefore, the electrolysis efficiency can be calculated by the following equation 1.

[0032]

## EQU1 ## Electrolysis efficiency [%] = dissolution loss [g / dm ² ] /
0.0821 [g / dm ² ] × 100 [%]

[Observation of Rough Surface] The surface of the aluminum alloy plate subjected to electrolytic surface roughening in the above-described measurement of electrolytic efficiency was observed with a scanning electron microscope. Then, the rough surface is observed at a magnification of 1000 with a scanning electron microscope, and when pits of about 7 to 10 μm are uniformly dispersed almost over the entire surface, ○ small pits of 3 μm or less or coarse pits of 15 μm or more Are mixed when X is mixed.

Table 1 shows the ratio of Fe intermetallic compound having a particle size of less than 1 μm, the electrolytic efficiency and the uniformity of the rough surface. As a result, in Examples 1 to 7, the composition and the ratio of the Fe intermetallic compound satisfied the first aspect of the present invention, and both the electrolytic efficiency and the uniformity of the rough surface were excellent. Examples 1 to 7 satisfied the production conditions described in claim 2 of the present invention, and the amount of the Fe intermetallic compound was sufficiently large.

On the other hand, in Comparative Example 1, the average heating rate was too high, and the holding time of the intermediate annealing was too short, so that the formation of fine Fe intermetallic compounds was insufficient. In Comparative Example 2, the holding temperature of the intermediate annealing was too high, and the amount of the fine Fe intermetallic compound was small. In Comparative Example 3, the holding temperature of the intermediate annealing was too low, and the amount of the fine Fe intermetallic compound was small. In Comparative Example 4, since the holding temperature of the intermediate annealing was too high and the holding time was too long, the amount of the fine Fe intermetallic compound was insufficient. In Comparative Example 8, since the homogenization temperature was too low, the Fe intermetallic compound having a particle size of 1 μm or more generated at the time of casting did not sufficiently form a solid solution. Did not. Further, in Comparative Example 5, the Fe content was small, the average heating rate was too high, and the intermediate annealing time was too short, so that the proportion of the Fe intermetallic compound was small. Therefore, Comparative Examples 1 to 5 and 8 all had low electrolytic efficiency and poor uniformity of the rough surface.

In Comparative Example 6, since the Fe content was small, the electrolysis efficiency was low, the reactivity was insufficient, and the uniformity of the rough surface was poor. In Comparative Example 7, since the Fe content was excessive,
The reactivity was excessive and the rough surface was uneven. Comparative Example 9
Since the Cu content was too large, uniform pits were not formed and the uniformity of the rough surface was poor. In Comparative Example 10, the Ni content of the inevitable impurities was too large, so that the reactivity became excessive and the uniformity of the rough surface was poor.

[0037]

As described above, according to the present invention,
Aluminum alloy for printing plates with high electrolysis efficiency, excellent reactivity, fine and uniform pits distribution, and excellent uniformity of rough surface in electrolytic roughening treatment with high current density and short time You can get a board.

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Claims (2)

[Claims] 1. Fe: 0.25 to 0.45 mass%, S
i: 0.02 to 0.08 mass%, Cu: 0.04 mass%
And the balance consists of Al and unavoidable impurities, and has a composition in which Ni in the unavoidable impurities is regulated to 0.005% by mass or less, and the Fe intermetallic compound having a particle size of 1 μm or less is 0.02% by mass. % Of an aluminum alloy plate for a printing plate. 2. Fe: 0.25 to 0.45 mass%, S
i: 0.02 to 0.08 mass%, Cu: 0.04 mass%
The aluminum alloy ingot having the following composition, with the balance being Al and inevitable impurities, having a composition in which Ni in the inevitable impurities is regulated to 0.005% by mass or less, is
A step of homogenizing at a temperature of 50 ° C. or higher, a step of hot rolling at a starting temperature of 400 to 450 ° C., and thereafter, heating at least once at an average heating rate of 10 to 60 ° C./hour to 450 Performing an annealing treatment at 1 to 20 hours at a temperature of from 500 to 500 ° C. to produce an aluminum alloy plate having an Fe intermetallic compound having a particle size of 1 μm or less of 0.02% by mass or more. A method for manufacturing an aluminum alloy plate for a printing plate.