JPH06227174A - Aluminum-plated steel sheet for lithographic printing supporter - Google Patents

Abstract

PURPOSE:To provide an aluminum-plated steel sheet for lithographic printing supporter, in which a uniform grain can be obtained by short-time electrolytic polishing. CONSTITUTION:The aluminum-plated steel sheet for lithographic printing supporter is featured including an aluminum plated layer with grain size of 0.2 to 5mum, a thickness of 1-10mum and an aluminum purity of 99.0 mass % or more having no Al group metal interlayer compound contained therein, on one surface or two surfaces of the steel sheet, and the steel sheet is in the form of a rolled structure.

Description

Detailed Description of the Invention

[001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum-plated steel sheet for a lithographic printing support, which can obtain uniform grain by electrolytic polishing for a short time.

[002]

2. Description of the Related Art At present, an aluminum alloy plate is widely used as a support for lithographic printing which is used for lithographic printing after forming a photosensitive layer such as a photosensitive resin on the surface of the plate,
This support is manufactured by degreasing an aluminum alloy plate, graining it by polishing, and then performing anodic oxidation treatment. Here, to make the surface grainy,
The water retention during printing and the adhesion to the photosensitive layer are enhanced, and the anodic oxidation treatment is performed to enhance printing durability.

As the graining method, a mechanical polishing method using a polishing ball or sandblast, a chemical polishing method of etching in an acid or alkaline solution, an electrolytic polishing method of electrolytic etching in an acidic solution, etc. have been put into practical use. The polishing method has a drawback that it becomes complicated because it requires removal of the abrasive and polishing debris remaining in the recesses after graining. Also, in the chemical polishing method, in order to make the depth and size of the sand uniform,
Not only must the liquid composition and the liquid temperature be controlled within a narrow range, but it also takes a long time for graining, so it is industrially difficult to carry out on a continuous line scale. Therefore, in recent years,
The electropolishing method, which can form a good grain in a relatively short time, has become the mainstream.

However, in the electrolytic polishing method, even if polished under the same conditions, the grain of the aluminum alloy plate remarkably changes depending on the surface condition and composition. For example, Japanese Patent Application Laid-Open No. 4-254545 discloses a countermeasure for electrolytically polishing a rolled plate, which causes streak-like unevenness and affects images. Further, in Japanese Unexamined Patent Publication No. 4-165041, irregular unevenness occurs due to the distribution state of Al-Fe-based and Al-Fe-Si-based intermetallic compounds having different electrolytic polishing properties from aluminum of the alloy plate, and non-image It is described that the ink adheres to the portion and the image quality becomes uneven.

As a method of eliminating the influence of the surface condition and composition, electrolytic polishing is easy, and A1 of high aluminum purity is used.
There is a method of using a material equivalent to 050 for the support. But,
When a high-purity aluminum plate becomes thinner, its strength decreases,
Folding and pecos tend to occur during handling, and plate elongation tends to occur during printing. In particular, burning processing (usually 200 to 3
These problems become more prominent when the treatment is performed at 00 ° C. for 3 to 10 minutes. Furthermore, this A1050 equivalent material has a proof stress of 150 even if the strength is increased by cold rolling.
Since it is only about N / mm ^{2, in} the case of a large size plate, the plate thickness had to be made as thick as 0.24 mm or more.

As a support having excellent strength, there is a method of using a cold-rolled hot dip aluminum plated steel sheet (JP-A-57-63292, JP-A-57-80097, JP-A-57-80097).
7-108255, 57-173196). However, the hot-dip aluminized steel sheet contains 3 to 6 mass% Fe.
% Inevitable, and since plating is performed with a plating bath containing 0.2 to 10 mass% of Si, Al-Fe based intermetallic compounds and Si are present in the surface layer of the plating layer. For this reason, it was difficult to make the grain uniform by electropolishing, and it was difficult to make the depth and size of the grain recess excellent in water retention and adhesion.

As another method, there is a method of using an aluminum-coated steel sheet coated with aluminum by a powder pressure welding method (Japanese Patent Laid-Open No. 58-55503). This steel sheet is obtained by applying aluminum powder to a steel sheet. 2 at 450 ° C
After heating for 5 minutes, cold rolling with a reduction rate of 5%
Since it is produced by a method of heating at 0 ° C. for 10 seconds, the aluminum coating layer is recrystallized in the heating step after rolling and the crystal grains become large, resulting in large pits and non-uniformity when electrolytically polished. However, the depth and size of the sand become uneven.

[0085]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an aluminum-plated steel sheet for a lithographic printing support, which can have a uniform grain.

[0109]

The present invention provides an aluminum-plated steel sheet having an aluminum purity of 99.0 mass% or more with a plating crystal grain of 0.2 to 5 μm on one or both sides of the steel sheet and not containing an Al-based intermetallic compound. The plated steel sheet having a thickness of 1 to 10 μm and a steel sheet having a rolled structure.

[0101]

[Function] The grain size of aluminum plating affects the depth and size of the grain recesses in electrolytic polishing, and the grain size is 0.2 μm.
If it is less than the above range, the recesses after electrolytic polishing become too fine, the water retention becomes poor at the time of printing, and the non-image area is stained. On the other hand, if the particle size exceeds 5 μm, the recesses become too large and the adhesion to the photosensitive layer deteriorates.

In addition to crystal grains, the aluminum plating has a purity of 99.0 mass% or more in order to enable uniform graining with excellent water retention and adhesion by electrolytic polishing for a short time. If the purity is lower than this, it becomes difficult to make the grain size and the recess depth uniform. In addition, impurities such as Al-F
If the e-based intermetallic compound is included, the grain becomes nonuniform even if the purity is high. Therefore, the Al-Fe based intermetallic compound is not included. Such high-purity aluminum plating containing no Al-Fe-based impurities may be formed by electroplating or vapor deposition plating. In these plating methods, Fe, Mn, Cr, etc. are mixed as unavoidable impurities into the plating layer, but no intermetallic compound is formed because all the metals are in a dispersed state. For example, since an Al-Fe intermetallic compound is usually not formed unless there is a temperature of 350 [deg.] C. or higher, an Al-Fe intermetallic compound is not formed by aluminum electroplating or vapor deposition plating that does not rise to such a temperature. .

The plating layer has a thickness of 1 to 10 μm. 1
If the thickness is less than μm, the base steel sheet is exposed during electrolytic polishing, making subsequent anodic oxidation treatment difficult, and the rust resistance during printing and storage deteriorates. On the other hand, if it exceeds 10 μm, there is no problem in performance, but it becomes expensive and the printing cost rises.

The base steel sheet has a rolled structure in order to exert strong strength even if it is thin. If the crystal structure is used, the strength is low, so that breakage and peko are likely to occur during handling.

The aluminum-plated steel sheet of the present invention is either cold-rolled ordinary steel steel strip, which is electrically or vapor-deposited aluminum-plated, or annealed ordinary steel steel strip is similarly aluminum-plated, and then cold-rolled. It can be manufactured by

In order to produce a lithographic printing support from the aluminum-plated steel sheet produced in this manner, degreasing, graining and anodizing treatment may be sequentially carried out as in the conventional case.
For degreasing, for example, the concentration is 1 to 5 mass% and the temperature is 20 to 60 ° C.
Alkaline etching by immersing in the sodium hydroxide solution for 2 to 30 seconds, or concentration 2 to 10 mass%, temperature 40
Immerse in sodium chloride solution at ~ 70 ° C to obtain a current density of 2
Electrolytic treatment may be performed at 10 kA / m ² for ² to 10 seconds. The amount of aluminum dissolved in the degreasing treatment is preferably 1 g / m ² or less, and it is not necessary to perform the degreasing treatment for a long time like an aluminum alloy plate.

Graining is carried out by electrolytic polishing, which is carried out in a hydrochloric acid or nitric acid solution and has a concentration of 0.2 to 3 mass.
A range of s%, preferably 0.5-1.5 mass% is suitable. The electrolysis conditions vary depending on how much sand is used, but generally the temperature is 20 to 50 ° C., preferably 30 to 4
It may be carried out at 0 ° C. and a current density (alternating current) of 3 to 20 kA / m ² , preferably 5 to 10 kA / m ² for 5 to 30 seconds. The alternating current may be a rectangular wave, a trapezoidal wave, or a normal alternating current, which is obtained by alternating the positive and negative polarities. This electrolytic polishing does not need to be carried out for a long time unlike an aluminum alloy plate. After graining, desmut treatment is applied to clean the surface. This desmut may be dipped in an aqueous solution of alkali or acid for 2 to 10 minutes.

The anodizing treatment was carried out with a sulfuric acid aqueous solution having a concentration of 10 to 40 mass% and a temperature of 10 to 40 ° C. and a current density of 0.1 to 1 k.
Electrolysis may be performed at A / m ² . After this treatment, a pore-sealing treatment with a silicate and a hydrophilic treatment with hot water may be carried out, if necessary.

The

【Example】

Example 1 An unannealed cold-rolled steel sheet was electrolytically degreased and pickled by a conventional method, and then electro-aluminum plated to a thickness of 5 μm under the following conditions to produce aluminum-plated steel sheets having different plated crystal grains. The aluminum plating purity of this steel sheet is 99.0m
It was more than ass%.

(Bath composition) Ethylimidazolium chloride 507 g / L Aluminum chloride 865 g / L (Plating conditions) Bath temperature 60 to 120 ° C. Plating solution flow rate 0.5 to 1.0 m / s Current density 0.05 to 5 kA / m ²

Next, each of the plated steel sheets was sequentially subjected to degreasing, electrolytic polishing, desmutting, anodic oxidation and sealing treatment under the following conditions to form a support, and then a photosensitive layer was formed to form a plate. Printed. (1) Degreasing treatment It was immersed in a sodium chloride solution having a concentration of 5 mass% and a temperature of 60 ° C., electrolyzed at a current density of 5 kA / m ² for 5 seconds, and washed with water. (2) Electrolytic polishing treatment In a nitric acid solution having a concentration of 1 mass% and a temperature of 35 ° C., electrolysis was performed for 9 to 12 seconds at a current density of 5 kA / m ² with a rectangular wave alternating current.

(3) Desmutting treatment: The sample was immersed in a sulfuric acid solution having a concentration of 20 mass% and a temperature of 50 ° C. for 3 minutes and then washed with water. (4) Anodizing Treatment In a sulfuric acid solution having a concentration of 20 mass% and a temperature of 20 ° C., electrolysis was performed for 1 minute at a current density of 0.2 kA / m ² with lead as a counter electrode. (5) Sealing treatment After immersing in a soda silicate aqueous solution having a concentration of 1 mass% and a temperature of 90 ° C for 1 minute, it was washed with water and dried.

(6) Formation of Photosensitive Layer 1.5 g of a photodimerization type photopolymer photosensitive liquid having the following composition was used.
It was applied to a film thickness of m ² . Condensation polyester of P-phenylenediacrylic acid diethyl ester and 1,4-dihydroxyethoxy-cyclohexane 4.0 g 2-benzoylmethylene-1-methyl-β-naphthothialine 0.32 g hydroquinone 0.08 g phthalocyanine blue- (pigment) 0.8 g Benzoic acid 0.16 g Monochlorobenzene 100 ml

Table 1 shows the plated crystal grains, grain after electrolytic polishing, and printability. The surface of the grain after electrolytic polishing was observed with a scanning electron microscope, and those with excellent uniformity of recesses were evaluated with a circle, good ones with a Δ mark, and inferior ones with a X mark. Further, the printability was evaluated by marking ◯ when the non-image area was excellent in stain resistance, Δ when good, and X when poor, after printing 100,000 copies with an offset printing machine.

[0242]

[Table 1]

Example 2 An unannealed cold-rolled steel sheet was electrolytically degreased and pickled by a conventional method, then heated to 200 to 300 ° C. in a vacuum, and subjected to ion beam activation treatment and vapor-deposited aluminum under the following conditions. Plating was performed to a thickness of 5 μm to produce aluminum-plated steel sheets having different plated crystal grains. The aluminum plating purity of this steel plate was 99.0 mass% or more. Then, the grain and printability of the obtained plated steel sheet were investigated in the same manner as in Example 1.
The results are shown in Table 2.

(1) Ion beam activation treatment Vacuum degree 1 × 10 ^-2 Pa Ar ion irradiation dose 15 C / m ² (2) Vapor deposition aluminum plating Vacuum degree 1 × 10 ^-2 Pa Heating method of vapor deposition bath Electronic beam Heating (scanning)

[027]

[Table 2]

Example 3 In Example 1, a plating bath to which MnCl ₂ and FeCl ₃ were added was used, and in Example 2, Fe, Mn, etc. were vapor-deposited in parallel with Al vapor deposition to obtain aluminum purity. Aluminum plated steel sheets with different thickness (plating thickness 5μ
m) was prepared, and the grain and printability of the plated steel sheet were investigated in the same manner as in Example 1. For the investigation, aluminum alloy plate JIS 1050 material (No. 11) and JIS 300 were used.
3 materials (No. 12), hot-dip aluminum plated steel sheet (N
No. 13) was used as a comparative material. The results are shown in Table 3.

[029]

[Table 3]

Even if the aluminum purity is 99.0% or more like the No. 11 aluminum alloy plate of the comparative material, Al
When the intermetallic compound is contained, the grain is inferior in the electrolytic polishing for a short time. In addition, as in Comparative Material No. 12, Al
Those containing Mn in addition to the intermetallic compound and having inferior aluminum purity are difficult to have good graining by electrolytic polishing for a short time. Further, in the hot-dip aluminum-plated steel sheet of Comparative Material No. 13, since the Al-based intermetallic compound and Si are present on the plated surface, uniform grain is not formed.

Example 4 In Examples 1 and 2, an annealed cold-rolled steel sheet was used as the steel sheet, followed by cold rolling after plating, and the plated steel sheet obtained in Examples 1 and 2 was temper-rolled. Then, the obtained plated steel sheet having a thickness of 0.24 mm was subjected to a burning treatment, and the mechanical properties before and after the treatment were investigated. Table 4 shows the results. The comparative material is JIS105 with a plate thickness of 0.24 mm.
It is 0 material.

[0332]

[Table 4]

[033]

INDUSTRIAL APPLICABILITY As described above, the aluminum-plated steel sheet of the present invention can be uniformly grained by electrolytic polishing when used for a lithographic printing support.

[Procedure amendment]

[Submission date] August 5, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 016

[Correction method] Change

[Correction content]

Graining is carried out by electrolytic polishing, which is carried out in a hydrochloric acid or nitric acid solution and has a concentration of 0.2 to 3 mass.
A range of s%, preferably 0.5-1.5 mass% is suitable. The electrolysis conditions vary depending on how much sand is used, but generally the temperature is 20 to 50 ° C., preferably 30 to 4
It may be carried out at 0 ° C. and a current density (alternating current) of 3 to 20 kA / m ² , preferably 5 to 10 kA / m ² for 5 to 30 seconds. The alternating current may be a rectangular wave, a trapezoidal wave, or a normal alternating current, which is obtained by alternating the positive and negative polarities. This electrolytic polishing does not need to be carried out for a long time unlike an aluminum alloy plate. After graining, desmut treatment is applied to clean the surface. This desmut may be dipped in an aqueous solution of alkali or acid for 1 to 10 minutes.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 017

[Correction method] Change

[Correction content]

The anodizing treatment was carried out with a sulfuric acid aqueous solution having a concentration of 10 to 40 mass% and a temperature of 10 to 40 ° C. and a current density of 0.1 to 1 k.
Electrolysis may be performed at A / m ² . After this treatment, sealing treatment with an aqueous silicate solution and hydrophilic treatment with hot water may be performed, if necessary.

Claims (1)

[Claims] 1. An aluminum plating layer having a plating crystal grain of 0.2 to 5 μm and an aluminum purity of 99.0 mass% or more and not containing an Al-based intermetallic compound, having a thickness of 1 to 10 μm on one or both sides of a steel sheet, An aluminum-plated steel sheet for a lithographic printing support, characterized in that the steel sheet has a rolling structure.