JP2001219662A - Aluminum alloy substrate for printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy substrate for a printing plate such as a PS plate which is improved in respect to the uniformity of a roughened surface formed by electrolytic etching. SOLUTION: This aluminum alloy substrate for the PS plate has a composition of Fe 0.11-0.60%, Si 0.01-0.20%, Ni 0.005-0.075%, Zn 0.005-0.075% and Cu less than 0.05% by wt.% and of Al and unavoidable impurities the residues, and satisfies the relations of Zn(%)<=0.08-Ni(%) and Fe(%)>=0.1+Si(%), while crystallized-precipitated matters of 0.01<=d<=2 (μm: 2×10-6 m) exist in the matrix thereof by 1×103<=n<=3×105 (pcs./mm2) when the diameter corresponding to a circle of the crystallized-precipitated matters is denoted by (d) and the number of pieces thereof by (n).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy support for a PS plate or the like used for lithographic printing, and more particularly to an aluminum alloy support excellent in uniformity of a rough surface by electrolytic etching.

[0002]

2. Description of the Related Art In lithographic printing, a photosensitive layer containing a photosensitive material such as a diazo compound is coated on a support made of an aluminum alloy, and a PS plate (Presensitized Plate) is exposed to an image.
A lithographic printing plate on which an image portion is formed by performing plate making processes such as development is wound around a cylindrical plate cylinder of a printing press, and ink is attached to the image portion in the presence of dampening water attached to the non-image portion. Lever ink is transferred to a rubber blanket and printed on paper.

As a support for the PS plate, an aluminum alloy plate which has been subjected to a surface treatment such as surface roughening treatment (graining) by electrolytic etching or the like, or anodizing treatment is used. Initially, as an aluminum alloy, JIS1050
(Pure Al with a purity of 99.5% or more), JIS1100 (A
1-0.05-0.20% Cu alloy), JIS3003
(Al-0.05 to 0.20% Cu-1.5% Mn alloy) has been mainly used.

[0004] The aluminum alloy support (1) has a uniform roughened surface by electrolytic etching. (2) Good adhesion of the photosensitive layer. (3) Various characteristics are required, such as that no stain is generated in the non-image area during printing. However, JIS105
0, JIS1100 and JIS3003 themselves could not sufficiently satisfy the above requirements,
Various improvements have been made.

[0005] For example, Japanese Patent Application Laid-Open No. 58-221254 discloses that Si 0.02 to 0.15%, Fe 0.1 to 1.0%.
%, Cu 0.003% or less, and a blank for offset printing comprising the balance Al and inevitable impurities are disclosed.
Japanese Patent Application Laid-Open No. 62-148295 discloses Fe0.
Aluminum alloy support for lithographic printing, comprising 0.05 to 1.0%, Si 0.2% or less, Cu 0.05% or less, the balance being Al and unavoidable impurities, and 0.012% or less of simple Si distributed in the metal structure. The body is disclosed.

Japanese Patent Application Laid-Open No. 58-221254 discloses Cu
Corrosion resistance decreases with an increase in the content, and due to this, stains in non-image areas increase during printing.
It is proposed to regulate it to 003% or less. Further, according to Japanese Patent Application Laid-Open No. 62-148295, a rough surface having uniform pits due to electrolytic etching is obtained, no streak (streak-like unevenness) is observed, and a stain on a non-image portion is suppressed during printing. It has the effect of being able to.

[0007] However, in response to a demand for improved printing accuracy,
JP-A-58-221254 and JP-A-62-148.
No. 295, it has been difficult to sufficiently cope with the conventional aluminum alloy support. In particular, it has become necessary to further improve the uniformity of the rough surface by electrolytic etching. In addition, there has been an increasing demand for forming a rough surface having excellent uniformity by a short-time electrolytic surface roughening treatment for cost reduction.

In response to this demand, Japanese Patent Application Laid-Open No. 9-184039
No .: Fe: 0.25 to 0.6% by weight, Si:
0.03 to 0.15%, Ti: 0.005 to 0.05
%, Ni: 0.005 to 0.20%, the balance being Al and unavoidable impurities, and 0.1 ≦ Ni / Si ≦
An aluminum alloy support for a printing plate characterized by satisfying 3.7 has been proposed.

In the aluminum alloy plate for a printing plate disclosed in Japanese Patent Application Laid-Open No. 9-184039, the chemical solubility, which is improved by adding Ni, is suppressed by the ability to suppress the chemical solubility of Si, so that the uniformity of the rough surface is improved. And the occurrence of pits due to immersion in an electrolytic solution in a non-energized state before the electrolytic treatment can be suppressed.

Japanese Patent Application Laid-Open No. 9-272937 discloses that, by weight%, Fe: 0.20 to 0.6%, Si: 0.03 to
0.15%, Ti: 0.005 to 0.05%, Ni:
0.005 to 0.20%, and 0.005 or more of one or more selected from the group consisting of Cu and Zn.
-0.050%, and 0.001 to 0.02 of one or more selected from the group consisting of In, Sn and Pb.
There has been proposed an aluminum alloy plate for a printing plate containing 0%, the balance being Al and unavoidable impurities.

The aluminum alloy plate for a printing plate disclosed in JP-A-9-272937 is prepared by adding one or more of Cu and Zn, and one or more of In, Sn and Pb, and solidifying in an aluminum matrix. By dissolving, the potential difference between the aluminum matrix and the intermetallic compound is adjusted to make the electrolytic rough surface uniform.

[0012]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 9-184 is disclosed.
No. 039 and the proposal of Japanese Patent Application Laid-Open No. 9-272937, the roughness uniformity is improved as compared with the prior art, but higher printing accuracy is required. Therefore, the present invention is to improve the roughness uniformity by electrolytic etching. It is an object to provide a more improved aluminum alloy support for a printing plate.

[0013]

The present inventors have studied the uniformity of electrolytic etching of an aluminum alloy support for a PS plate in order to solve the above-mentioned problems, and have found the following. (1) Al-Fe-based intermetallic compounds that crystallize or precipitate in an aluminum matrix act as cathode points during electrolytic etching to control their solubility. (2) When Ni is added, it is taken into the Al-Fe-based intermetallic compound and becomes an Al-Fe-Ni-based intermetallic compound, whereby the uniformity of dissolution can be improved. (3) Zn weakens the natural oxide film formed on the surface of aluminum, thereby improving the uniformity of the rough surface.
However, when Zn is added excessively, the effect of weakening the oxide film becomes too large, and the amount of dissolution at the time of electrolytic etching becomes excessive, thereby deteriorating the uniformity of the rough surface.

(4) By setting the amounts of Ni and Zn to be in a predetermined relationship, uniformity of the rough surface by electrolytic etching can be ensured. (5) Si forms an Al-Fe-Si-based intermetallic compound. If the amount of the Al-Fe-Si-based intermetallic compound is excessive, the uniformity of the rough surface obtained by electrolytic etching is impaired. . Therefore, it is necessary to adjust the content in relation to the Fe content.

The aluminum alloy support for a printing plate of the present invention is based on the above-mentioned findings.
0.11 to 0.60%, Si: 0.01 to 0.20%,
Ni: 0.005 to 0.075%, Zn: 0.005 to
It has a composition of 0.075%, Cu less than 0.05%, balance Al and unavoidable impurities, and Zn (%) ≦ 0.08
−Ni (%), Fe (%) ≧ 0.1 + Si (%), assuming that the equivalent circle diameter of crystals and precipitates is d and the number is n, 0.01 ≦ d ≦ 2 (μm ： 2 × 10
⁻⁶ m) of crystals / precipitates of 1 × 10 ³ ≦ n ≦ 3 × 10 ⁵ (pieces /
mm ² ).

In the present invention, the crystals and precipitates are Al--Fe
, Al-Fe-Ni and Al-Fe-Si based intermetallic compounds.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The components of the present invention and other reasons for limitation will be described below. <Fe: 0.11 to 0.60%> Fe forms an Al-Fe-based intermetallic compound, improves the uniformity of the rough surface by electrolytic etching, and improves the fatigue resistance. However, if it is less than 0.11%, this effect is insufficient, and if it exceeds 0.60%, the intermetallic compound tends to be coarse, thereby impairing the uniformity of the rough surface by electrolytic etching. The range is 0.60%. Desirable Fe
Is 0.2 to 0.4%.

<Si: 0.01 to 0.20%> Si forms an Al-Fe-Si-based intermetallic compound and promotes the refining of recrystallized grains during hot rolling. If the content is less than 0.01%, this effect is insufficient, and coarse crystal grains are generated, thereby impairing the uniformity of the rough surface due to electrolytic etching and generating a light unetched portion called a streak. On the other hand, 0.
If it exceeds 20%, the Al-Fe-Si-based intermetallic compound becomes coarse, which impairs the uniformity of the rough surface by electrolytic etching. Therefore, Si is set to 0.01 to 0.20%. Desirable Si content is 0.04 to 0.08%.

When Si becomes excessive in relation to Fe, the amount of Al—Fe—Si based intermetallic compound increases, which impairs the uniformity of the rough surface due to electrolytic etching. Therefore, in the present invention, as described above, Fe (%) ≧
It is desirable to satisfy the relationship of 0.1 + Si (%).

<Ni: 0.005 to 0.075%> Ni
Is taken into the Al-Fe intermetallic compound and Al-Fe
-Becomes a Ni-based intermetallic compound and has the effect of improving dissolution uniformity. However, if it is less than 0.005%, this effect is insufficient, and the uniformity of the rough surface by the electrolytic etching is not sufficiently improved. On the other hand, if it exceeds 0.075%, Al—Fe—
The Ni-based intermetallic compound becomes coarse and the rough surface formed by electrolytic etching becomes non-uniform. Therefore, in the present invention, the content is in the range of 0.005 to 0.075%. Desirable Ni
Is 0.01 to 0.03%.

<Zn: 0.005 to 0.075%> Zn
, As described above, weakens the oxide film formed on the surface of aluminum, thereby improving the uniformity of the rough surface. However, if less than 0.005%, this effect is insufficient,
On the other hand, if added excessively, the effect of weakening the oxide film becomes too large, so the content is made 0.075% or less.

Both Zn and Ni have the effect of increasing the solubility of the material, and when both are added in excess, the solubility of the material is increased and conversely, the uniformity of the rough surface is reduced. According to the study of the present inventors, the contents of Ni and Zn are set to Zn (%) ≦ 0.08.
It has been found that the above-mentioned inconvenience does not occur if regulation is performed so as to satisfy -Ni (%).

<Cu: less than 0.05%> Cu makes the etching property of the material non-uniform when contained in a very small amount. That is, it is an element that inhibits the uniformity of the rough surface after electrolytic etching. In particular, non-uniformity is large in an aluminum alloy containing Ni and Zn. Therefore, in the present invention, less than 0.05%, preferably less than 0.02%, more preferably 0.005%
And The most desirable Cu content for the best etchability is less than 0.003%.

<Other Impurity Elements> The aluminum alloy support for a printing plate of the present invention contains unavoidable impurity elements in addition to the above elements, but the object of the present invention is not impaired within the following ranges. Mg: 0.02% or less Ti: 0.03% or less V: 0.01% or less B: 0.002% or less

Next, the aluminum alloy for a printing plate of the present invention
The crystals / precipitates of the support will be described. Investigation by the present inventors
According to the discussion, the size and size of the intermetallic compound
Amount affects the uniformity of the rough surface by electrolytic etching.
You. That is, the circle equivalent diameter d is 0.01 μm (0.01 ×
10^-6For intermetallic compounds less than m), the starting point of etching
However, if it exceeds 2 μm, the uniformity is impaired. Ma
In addition, 1 × 10 ^ThreePieces / mm^TwoLess than etch
Surface roughness due to the small number of intermetallic compounds
One sex is a decoy, and 3 × 10^FivePieces / mm^TwoExceeds
The resolvability becomes too high and the uniformity of the rough surface is reduced.

The size and amount of the crystals and precipitates depend on the casting conditions (mainly the cooling rate), the homogenization treatment performed after casting, and the hot rolling conditions (mainly the rolling temperature). In the present invention, it is effective to omit the homogenization treatment usually performed on the present aluminum alloy. That is, the homogenization treatment has the advantage that crystals and precipitates are uniformly dispersed in the matrix, but tends to be coarse. Therefore, in the present invention, it is effective to prevent coarsening of crystals and precipitates and improve the uniformity of the rough surface.

A description will now be given of a study in terms of production which is effective for the aluminum alloy support for a printing plate of the present invention. <Casting> Casting is not particularly limited in producing the aluminum alloy support for a lithographic printing plate of the present invention,
For example, a conventionally known casting method such as a DC casting method can be applied.

<Heat Treatment> Generally, the ingot obtained by casting is subjected to a homogenization heat treatment in a temperature range of 450 to 600 ° C. This homogenization heat treatment causes a part of Fe to form a solid solution and the Al-Fe intermetallic compound to be uniformly and finely dispersed. However, as described above, it is not an essential step in the present invention.

Even when the homogenization treatment is performed, 0.01 ≦ d ≦ 2, where d is the equivalent circle diameter of the crystal / precipitate and n is the number thereof.
(2 μm: 2 × 10 ⁻⁶ m) crystals and precipitates are 1 × 10 ³ ≦
It is desirable to control the temperature and the holding time so that n ≦ 3 × 10 ⁵ (pieces / mm ² ). After the homogenization heat treatment, the ingot can be cooled once and then subjected to the soaking treatment for the next step of hot rolling. Alternatively, the hot rolling can be performed directly from the homogenization heat treatment.

<Hot rolling> After the homogenizing heat treatment, hot rolling is performed. Hot rolling is suitably performed in a temperature range of 300 to 600 ° C. If the temperature exceeds 600 ° C., the recrystallized grains become coarse, and streaks tend to occur due to the surface roughening treatment.

<Cold Rolling> After hot rolling, cold rolling is performed. This cold rolling disperses the Al-Fe intermetallic compound and makes the crystal structure uniform and fine. In order to obtain this effect, it is necessary to reduce the area by 50%, preferably 70% or more.

<Annealing> After cold rolling, annealing is performed mainly for imparting appropriate strength and elongation to the sheet material. Annealing is performed in a temperature range of 300 to 600 ° C. If the temperature is lower than 300 ° C., the object cannot be achieved. If the temperature is higher than 600 ° C., oxidation of the surface becomes remarkable, which is not preferable. Desirable annealing temperature is 350-500 ° C. Annealing may be performed in any of a continuous annealing furnace and a batch annealing furnace.

<Finish Cold Rolling> After annealing, cold rolling is performed again. The purpose of this cold rolling is to adjust and finish the hardness required for the aluminum alloy support for a printing plate. Since the hardness required for the printing plate aluminum alloy support for PS plate or the like is the H _16, to adjust the rolling reduction to accommodate this.

<Surface Treatment> After the finish cold rolling is completed, the surface is immersed in an electrolytic solution such as hydrochloric acid or nitric acid to perform a surface roughening treatment by electrolytic etching. The surface roughening treatment is performed to improve the adhesion to the photosensitive layer in the image area and to improve the hydrophilicity and water retention in the non-image area. After performing the surface roughening treatment, the surface may be subjected to an anodic oxidation treatment to improve the wear resistance and hydrophilicity of the surface.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. <Example 1> An alloy slab having a composition (wt.
Obtained by C casting method. The casting speed is 30 mm / min and the slab thickness is 200 mm. The slab was heated to 510 ° C., then hot-rolled, and subjected to annealing and cold rolling to obtain a 0.3 mm-thick plate-shaped test material.

[0036]

[Table 1]

The obtained test material was immersed in a 10% aqueous sodium hydroxide solution at 50 ° C. for 30 seconds, degreased, and then baked at 25 ° C.
Desmut treatment was performed by dipping in 10% nitric acid for 30 seconds. Next, this test material was immersed in 2% hydrochloric acid at 25 ° C.
AC electrolytic etching was performed with a sine wave of 60 Hz and 50 A / dm2, followed by a desmutting process of immersing in a 50% aqueous solution of 10% sodium hydroxide for 6 seconds and then immersing in 25% of 10% nitric acid for 30 seconds. Dried. After drying,
The rough surface was photographed with a scanning electron microscope (SEM) at a magnification of 500 × 0.0252 mm ² to evaluate the pit uniformity. In the evaluation, the circle equivalent diameter was 5 μm (5 × 10
The total area of the pits exceeding ⁻⁶ m) was less than 5% of the evaluation area, and ピ ッ ト was obtained when the total area was 5% or more. Further, the etched surface of 50 × 100 mm ^{2 was} visually observed, and the case where an unetched portion was observed was evaluated as x, and the case where it was not observed was evaluated as ○.

The results are shown in Table 1, and the results are shown in Example No. 1 according to the present invention. 1 to No. 3 has excellent pit uniformity,
In addition, no unetched portion was observed, indicating that the rough surface uniformity by electrolytic etching was excellent.

Comparative Example No. In No. 4, since the Zn content exceeds the range of the present invention, the solubility is excessively increased, and the pit uniformity is hindered.

Comparative Example No. 5, the effect of weakening the oxide film on the aluminum surface was insufficient because the Zn content did not reach the range of the present invention, and the pit uniformity was poor.
In addition, unetched portions were observed.

Comparative Example No. In No. 6, since the Si content exceeded the range of the present invention and the Zn content did not reach the range of the present invention, the pit uniformity was poor, and in addition, an unetched portion was observed.

Comparative Example No. No. 7 shows that the Si content is beyond the range of the present invention, and in relation to Fe,
(%) ≧ 0.1 + Si (%)
Poor pit uniformity.

Comparative Example No. 8 is within the scope of the present invention in terms of composition, but 0.01 ≦ d ≦ 2 (μm: 2 × 10 ⁻⁶⁾
m) is 1 × 10 ³ ≦ n ≦ 3 × 10
^Since it exceeded the range of ⁵ (pieces / mm ² ), an unetched portion was observed.

Comparative Example No. In No. 9, since the Cu content exceeded the range of the present invention, the uniformity of pits was poor, and in addition, unetched portions were observed.

[0045]

As described above, according to the present invention, the weight%
And Fe: 0.11 to 0.60%, Si: 0.01 to
0.20%, Ni: 0.005 to 0.075%, Zn:
It has a composition of 0.005 to 0.075%, less than 0.005% of Cu, and the balance of Al and unavoidable impurities.
(%) ≦ 0.08−Ni (%), Fe (%) ≧ 0.1 +
Assuming that the relationship of Si (%) is satisfied, the equivalent circle diameter of crystals and precipitates is d, and the number is n, 0.01 ≦ d ≦ 2 (μ
m: 2 × 10 ⁻⁶ m) 1 × 10 ³ ≦ n ≦ 3
Since the aluminum alloy support for a printing plate is characterized by the presence of × 10 ⁵ (pieces / mm ² ), a roughened surface by electrolytic etching can be formed more uniformly than a conventional support.

Continued on the front page (72) Inventor Mitsuo Ishida 1st section of Showa, Chiyoda-cho, Yuraku-gun, Gunma Prefecture Inside the Gunma Plant of Kodak Polychrome Graphics Co., Ltd. (72) Inventor Keitaro Yamaguchi 85-85 Hiramatsu, Susono City, Shizuoka Prefecture Mitsubishi Aluminum F-term in the Technology Development Center Co., Ltd. (reference) 2H114 AA04 AA14 BA10 DA04 DA64 EA02 GA08 GA09

Claims (2)

[Claims] 1. Fe: 0.11 to 0.60% by weight
%, Si: 0.01 to 0.20%, Ni: 0.005 to
0.075%, Zn: 0.005 to 0.075%, Cu
It has a composition of less than 0.05%, the balance being Al and unavoidable impurities, Zn (%) ≦ 0.08-Ni (%), Fe
(%) ≧ 0.1 + Si (%)
If the equivalent circle diameter of crystals and precipitates is d and the number is n, 0.0
Crystals and precipitates of 1 ≦ d ≦ 2 (μm: 2 × 10 ⁻⁶ m) are contained in the matrix at 1 × 10 ³ ≦ n ≦ 3 × 10 ⁵ (pieces / mm)
² ) An aluminum alloy support for a printing plate, characterized by being present. 2. Crystals and precipitates are Al-Fe, Al-F
The aluminum alloy support for a printing plate according to claim 1, wherein the aluminum alloy support is mainly composed of one or more of e-Ni-based and Al-Fe-Si-based intermetallic compounds.