JPH06108290A - Continuous electrolytic treatment device - Google Patents

Abstract

PURPOSE:To efficiently perform the electrolytic treatment while preventing a current from concentrating in the side end part and sneaking round to the rear side by making the effective area of a high current density smaller than that of a low current density in an electrode arranged to face a band-shaped metallic plate running in an electrolyte. CONSTITUTION:A band-shaped Al product is run in the electrolyte like sulfuric acid, and power is supplied between this product and an electrolytic electrode facing it to perform the anodic oxidation treatment. In this electrolytic treatment device, this electrolytic electrode 8 is so constituted that the effective area of at least a part of the electrode where the current density exceeds about 5A/dm<2> is smaller than that where the current density does not exceed about 5A/dm<2>. For example, the electrolytic electrode 8 is so formed that the width is stepwise changed in the running direction of an arrow (a) of the Al product 7, and the electrolytic electrode 8 consists of a wide electrode part 9 wider than the Al product 7 and a narrow electrode part 10 narrower than it. The wide electrode part 9 consists of a low current density part (b) having <5A/dm<2> current density, and the narrow electrode part 10 consists of a high current density part (c) having >=5A/dm<2> current density.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for continuously electrolytically treating a strip-shaped metal plate such as anodizing treatment of an aluminum plate used for a lithographic printing plate support.

[0002]

2. Description of the Related Art Generally, an aluminum support used for a lithographic printing plate is required to have excellent hydrophilicity and water retention property, and therefore, the surface thereof is finely divided by a mechanical, chemical or electrochemical method. Rough surface is formed by forming irregularities. Further, in order to improve the mechanical strength and the water retention of the roughened surface, the surface is generally anodized.

Conventionally, the anodizing treatment of the support for a lithographic printing plate has been carried out by JP-A-48-26638, JP-B-58-24517 and JP-A-47.
The method is carried out by the anodizing method disclosed in each of Japanese Patent Publication No. 18739, etc., and this method is called a so-called submerged power supply method. As an anodizing apparatus (so-called flat type) by this submerged power feeding method, for example, there is an apparatus shown in FIG.

The anodizing apparatus shown in FIG. 12 includes a power supply tank 32 for negatively charging the aluminum product 31, an anodizing tank 33 for anodizing the aluminum product 31,
An intermediate portion 34 that prevents a short circuit of current between the power feeding tank 32 and the anodizing treatment tank 33 is provided, and an electrolytic solution 35 is stored in the power feeding tank 32 and the anodizing treatment tank 33. And the power supply tank 32
A power supply electrode 36 is arranged in the electrolytic solution 35, and an electrolytic electrode 37 is arranged in the anodizing tank 33 in the electrolytic solution 35. The power supply electrode 36 and the electrolytic electrode 37 are connected to each other via a DC power supply 38. The electrolytic electrode 37 in the anodizing treatment tank 33 is shown in FIG.
As shown in, the width is formed longer than the width of the aluminum product 31.

In such an anodizing apparatus,
A current from the DC power supply 38 flows in the power supply tank 32 from the power supply electrode 36 through the electrolytic solution 35 to the aluminum product 31, and the current flows in the aluminum product 31 to the anodizing treatment tank 33. As a result, the aluminum product in the anodizing tank 33 is
An anodized film is formed on the surface of 31.

[0006]

On the other hand, in the production line of the lithographic printing plate support, the size of the lithographic printing plate product is very diverse, so that the aluminum product, which is the object to be processed, usually has various widths. Is used.

Therefore, conventionally, as shown in FIG. 13 described above, the width of the electrolytic electrode is made wider than the maximum width of the aluminum product so that it can be applied to all various aluminum products.

Therefore, in the anodizing treatment tank, the electric current is concentrated on the side end portions of the aluminum product, and the amount of the oxide film on both side end portions is increased as compared with the central portion. Such a phenomenon does not become a problem when the amount of supplied current is small, but when increasing the processing line speed to improve productivity or increasing the anodized film amount to improve quality performance, It is necessary to increase the current density, and when the current density is increased, the amount of oxide film on the side edges of aluminum products increases significantly, which exceeds the allowable limit in terms of quality and causes so-called discoloration due to local concentration of reactions. It was a failure. Therefore, it was not possible to increase the current density, and it was not possible to speed up the processing line or increase the amount of anodized film. In addition, the equipment is large and the equipment cost is high.

Furthermore, an electric current circulates to the back surface of the surface to be processed of the aluminum product, and the efficiency of film formation on the surface to be processed is reduced. Therefore, the present applicant has proposed an anodizing device in which the width of the electrode is narrowed or a masking plate is provided between the electrode and the strip-shaped metal plate (Japanese Patent Application No. 3-294204).
issue).

The present invention is to further improve the above-mentioned proposed technique and provide a continuous electrolytic treatment apparatus capable of more efficiently performing electrolytic treatment while preventing the concentration of electric current on the side end portion and the sneak to the back surface. To aim.

[0011]

The present invention has been made to achieve the above object, and a continuous electrolytic treatment apparatus of the present invention has an electrolytic solution and an electrode provided in the electrolytic solution. In an apparatus for electrolytically treating a strip-shaped metal plate by running the strip-shaped metal plate in an electrolytic solution, the effective area of at least a part of the electrode having a current density of more than 5 A / dm ² is 5 A / dm ^2.
The feature is that it is smaller than the effective area of the electrode that does not exceed ² .

[0012] The current density was divided electrodes on whether more than about 5A / dm ^2, if the current density exceeds about 5A / dm ^2, around the concentrate and the back surface of the current to the side edge This is because the harmful effects of inclusion are great. In addition, this adverse effect fluctuates due to various electrolysis conditions. Therefore, in accordance with this fluctuation, the range in which the effective area is reduced in the electrodes whose current density exceeds approximately 5 A / dm ² (1/2 of the electrode, 2 / 3 part, all etc.). The effective area is an area that contributes to the electrolytic treatment of the electrodes.

[0013] at least a portion of the effective area of the current density exceeds about 5A / dm ² electrode, as a means to be smaller than the effective area of the electrode current density does not exceed about 5A / dm ^2, for example, current density at least a portion of the width of the electrode in excess of about 5A / dm ^2, means for reducing formation than the width of the width and the strip metal plate electrode current density does not exceed about 5A / dm ^2, current density of about 5A / dm ² There is a means for forming a notch in the side end of at least a part of the electrode exceeding 5 cm, and a means for providing a masking plate at the side end of at least a part of the electrode having a current density exceeding approximately 5 A / dm ² .

[0014] at least a portion of the width of the current density exceeds about 5A / dm ² electrodes, the means to smaller than forming width of width and strip metal plate electrode current density does not exceed about 5A / dm ^2, small The width is appropriately set to an optimum length depending on the width of the strip-shaped metal plate, the distance between the strip-shaped metal plate and the electrodes, and the like. For example, when the width of the strip-shaped metal plate is 1000 mm and the distance between the strip-shaped metal plate and the electrode is 20 mm, the range of 300 to 900 mm is preferable, and the range of 500 to 800 mm is particularly preferable.

Means for forming one or more notches and holes in at least a portion of the electrode having a current density of greater than about 5 A / dm ² is
For example, the side end portion of the electrode is formed in a continuous triangle, quadrangle, arc shape, or the like, or a hole is formed in the entire electrode and the hole is made smaller toward the side end.

In the means for providing a masking plate on the side edge of at least a part of the electrode having a current density of more than about 5 A / dm ² , the masking plate is between the electrode and the strip-shaped metal plate.
It is provided at least at a position not facing the strip-shaped metal plate but facing the electrode. That is, when the masking plate is the minimum, the inner side edge of the masking plate coincides with the side edge of the strip-shaped metal plate, and in other cases, the inner side edge of the masking plate is the side edge of the strip-shaped metal plate. It is located inside. The position of the inner side edge of this masking plate is
It is appropriately determined by the width of the strip-shaped metal plate, the width of the electrode, the distance between the strip-shaped metal plate and the electrode, for example, 20 from the side edge of the strip-shaped metal plate.
A range of 0 mm is preferred. If the inner side edge of the masking plate is outside the side edge of the strip-shaped metal plate, the concentration of current on the side edge of the strip-shaped metal plate cannot be effectively suppressed, and the inner side edge of the masking plate is From the side edge of the board to the inside
If it is inside 200 mm, the amount of anodized film on the side edge of the strip-shaped metal plate will be smaller than usual.

Such a masking plate is provided on the surface of the electrode, and it is possible to use an electrode cover in which the central portion has a larger aperture ratio than the side end portions in the width direction of the strip-shaped metal plate. The electrode cover is provided with an opening, and the opening ratio of the opening is larger in the central portion. For example, when the opening has a circular shape, the central portion has a large diameter and the side end portions have a small diameter, or the central portion has a base and the side end has an apex.

Further, the continuous electrolysis apparatus of the present invention has an electrolytic solution and electrodes provided in the electrolytic solution, and is an apparatus for electrolytically treating the strip-shaped metal plate by running the strip-shaped metal plate in the electrolytic solution. In at least a part of the electrodes having a current density of more than about 5 A / dm ² , the distance between the electrode and the strip-shaped metal plate becomes longer toward the side edge in the width direction of the strip-shaped metal plate. It is configured.

In order to make the distance to the strip-shaped metal plate longer toward the side edge, the cross-sectional shape is formed so as to project toward the strip-shaped metal plate toward the center. This protruding shape may be continuous or discontinuous. For example, the continuously changing shape may be a circular arc shape, an isosceles triangle shape, a parabolic shape, or the like. There is a staircase shape as the shape that changes to.

The strip-shaped metal plate may be a strip-shaped metal plate made of pure aluminum or an aluminum alloy. Examples of the aluminum alloy include metals such as silicon, iron, copper, manganese, magnesium, chromium, zinc, bismuth and nickel. There is an aluminum alloy. The thickness of the strip-shaped metal plate is generally in the range of 0.1 to 0.5 mm.

The electrolytic solution may be, for example, an aqueous solution of sulfuric acid, phosphoric acid, oxalic acid or a salt thereof, or a mixed solution thereof, and an optimum one may be selected to obtain a desired quality. The concentration and temperature of the electrolytic solution can be freely selected. As the power supply waveform, a direct current is generally used, but in addition, an optimum waveform such as an AC waveform or an AC / DC superposed waveform can be selected to obtain a desired quality. As the current density during electrolytic treatment,
You can choose freely. For example, the value may be constant during the processing time, or the current density may be gradually increased.

The continuous electrolytic treatment method and apparatus of the present invention can be applied to anodizing treatment, electrolytic etching treatment, electrolytic plating treatment and the like. When it is used as an anodizing device, it can be applied to a conventionally used known anodizing device (flat type), but a supporting roller for supporting the strip-shaped metal plate and at least one of the upstream and downstream of the supporting roller. It can also be applied to a device (radial type) having a power feeding roller provided in contact with a band-shaped metal plate and a substantially concentric electrode provided along the outer peripheral surface of the supporting roller.

When the present invention is used in an anodizing apparatus for a lithographic printing plate, a roughening treatment is usually performed before the anodizing treatment. This roughening treatment is for improving the water retention of the aluminum support and the adhesion to the photosensitive material coated on the aluminum support.
It is carried out by a chemical surface roughening method, an electrochemical surface roughening method or a combination thereof.

As the mechanical surface roughening method, there are a wire brush graining method, a brush graining method, a sandblast method, a ball graining method and the like. Examples of the chemical surface roughening method include a method of selectively dissolving the surface. As an electrochemical graining method, there is a method using nitric acid, hydrochloric acid and a mixed solution thereof as an electrolytic solution. Furthermore, salts such as aluminum nitrate, aluminum chloride, ammonium nitrate, ammonium chloride, manganese nitrate, manganese chloride, iron nitrate and iron chloride may be added thereto. Further, an aqueous solution of a neutral salt such as sodium chloride or sodium nitrate can also be used.

Further, after the surface roughening treatment and before the anodizing treatment, if necessary, an alkali etching treatment, a neutralization treatment,
Desmutting treatment or the like can be appropriately selected and combined. In addition, two or more units may be connected in the longitudinal direction with the above-mentioned device as one unit, and the same anodizing treatment described above may be repeated a plurality of times.

After subjecting the strip-shaped metal plate to anodizing treatment, if necessary, the sealing treatment described in JP-A-1-150583, JP-A-60
-149491 disclosed hydrophilic treatment, U.S. Pat. No. 3,181,461, aqueous alkali metal silicate solution treatment, U.S. Pat.No. 3,860,426, hydrophilic cellulose-containing undercoat layer coating containing a water-soluble metal salt are appropriately selected. Can be implemented.

When the strip-shaped metal plate according to the present invention is used as a lithographic printing plate support, a photosensitive layer can be provided on the surface of the lithographic printing plate support to prepare a photosensitive lithographic printing plate. The composition of the photosensitive layer includes a diazo resin, an o-quinonediadizo compound, a photosensitive azide compound, a photopolymerizable composition, and a photosensitive resin having an unsaturated double bond in the molecule. And the like.

[0028]

According to the present invention, the effective area of the electrode is reduced or the distance between the side end of the electrode and the strip-shaped metal plate is increased at the portion of the electrode where the electric current concentrates on the side edge or sneak into the back surface. As a result, the current is prevented from concentrating and sneaking into the side end, and the current is sufficiently supplied to the electrode portion where the current is not concentrating on the side end or sneaking into the back surface.

An example of the continuous electrolytic treatment apparatus for a strip-shaped metal plate of the present invention will be described with reference to the drawings. 1 is a schematic view of an anodizing device for a lithographic printing plate support, FIG. 2 is a plan view of an electrolytic electrode, FIG. 3 is a sectional view taken along line AA in FIG. 2, and FIG. 4 is BB in FIG.
It is a line sectional view. In these figures, the power feeding tank 1, the anodizing tank 2, the intermediate portion 3, the power feeding electrode 4, the electrolytic solution 5 and the DC power source 6 are configured in substantially the same manner as the conventional anodizing device shown in FIG. The same applies to the aluminum product 7.

In FIG. 1, reference numeral 8 is an electrolytic electrode for anodizing the aluminum product 7, and this electrolytic electrode 8
2 is formed so that the width changes stepwise along the traveling direction a of the aluminum product 7, as shown in FIG. 2, and as shown in FIG. It is composed of a portion 9 and a narrow electrode portion 10 narrower than the width of the aluminum product 7, as shown in FIG.
The wide electrode portion 9 has a current density of 5 A / dm ²
Is a low current density portion b, and the narrow electrode portion 10 is a high current density portion c having a current density of 5 A / dm ² or more.

To perform anodization with the anodizing device as described above, the power supply electrode 4 and the electrolytic electrode 8 are energized by the DC power source 6 in the same manner as in the conventional case, whereby the aluminum product 7 is stored in the anodizing tank 2. An anodic oxide film is formed on the surface. At this time, in the narrow electrode portion 10, the aluminum product 7
Since the width of the narrow electrode portion 10 is smaller than the width of, the current is supplied to the front surface of the aluminum product 7 substantially evenly. Further, in the wide electrode portion 9, current concentrates on the side end portion of the aluminum product 7, but since the current density is small, unevenness of the film, burn failure, and film formation on the back surface hardly occur.

[0032] Figure 5, a current density of at least a portion of the width of the electrode in excess of about 5A / dm ^2, the current density was smaller than the width and the width of the strip-shaped metal plate electrodes not exceeding about 5A / dm ² FIG. 6 is a plan view of another example of an electrode. Example electrode shown in FIG.
11 is a wide electrode portion 12 wider than the width of the aluminum product 7
And the narrow electrode part 13 narrower than the width of the aluminum product 7,
They are formed alternately at substantially equal intervals.

FIG. 6 is a partial plan view of an electrode in which one or more kinds of notches and holes are formed in at least a part of the electrode having a current density exceeding about 5 A / dm ² . Example electrode 15 shown in FIG.
Has rectangular notches 16 formed at both ends at regular intervals.

In FIGS. 7, 8 and 9, the current density is about 5 A /
FIG. 9 is a partial plan view of an electrode portion of an example in which a masking plate is provided on at least a side end portion of an electrode exceeding dm ² .

The electrode 11 of the example shown in FIG. 7 is the same as the conventional one, but a masking plate 15 is fixed to the upper surface of the electrode 11 leaving a part of the center thereof. In this masking plate, rectangular notches 16 are formed at regular intervals on the center side. Therefore, the exposed area of the side end portion of the electrode 11 is smaller than that of the central portion.

Although the electrode 18 of the example shown in FIG. 8 is the same as the conventional one, a masking plate 19 is fixed to the upper surface of the electrode 18 leaving a part of the center thereof. The masking plate 19 is provided with a large number of circular holes 20, that is, the electrodes 18 are exposed in the holes 20. The size of the holes 20 becomes larger toward the central portion side. Therefore, the exposed area of the electrode 18 increases toward the center.

The electrode 22 of the example shown in FIG. 9 is the same as the conventional one, but a masking plate 23 is fixed to the side end of the electrode 22. The masking plate 23 has isosceles notches 24 formed at regular intervals on the center side. Therefore, the exposed area of the side end portion of the electrode 22 is smaller than that of the central portion.

FIGS. 10 and 11 show that at least a part of the electrode having a current density of more than about 5 A / dm ² is arranged such that the distance from the strip-shaped metal plate becomes longer toward the side edge in the width direction of the strip-shaped metal plate. It is sectional drawing of the anodization tank of the example formed.

The electrode 25 of the example shown in FIG. 10 is formed into an isosceles triangle whose upper surface (the surface facing the aluminum product) has a high center and both ends are low. Example electrode shown in Figure 11
27 has an upper surface (a surface facing an aluminum product) formed in an arc shape having a high center and low side edges.

[0040]

【Example】

Strip-shaped metal plate to be anodized: A long JIS 1050 aluminum strip-shaped product (thickness 0.2 mm, width 1000 mm) was subjected to the following treatment at a line transfer speed of 50 m / min. First,
The surface was grained with a rotating nylon brush using the Pamisu water suspension as an abrasive. At this time, the surface roughness (center line average roughness) was 0.5 μm. After washing with water, etching was carried out in a 10% aqueous solution of caustic soda at 70 ° C. so that the amount of aluminum dissolved was 6 g / m ² . After washing with water, the mixture was neutralized in a 30% aqueous solution of nitric acid and washed again with water. Thereafter, in a 0.7% nitric acid aqueous solution, a rectangular wave alternating waveform having a voltage of 13 V for the anode and a voltage of 6 V for the cathode was used (power supply waveform described in the example of JP-A-52-77702) for 20 seconds for electrolytic surface roughening. The surface was washed with a 20% aqueous solution of sulfuric acid, and then washed with water.

Example 1 The above aluminum product was anodized by using the electrode having the form shown in FIG. The width of this electrode was 600 mm. The conditions of the anodizing treatment were as follows: an electrolytic solution was an aqueous solution of sulfuric acid of 150 g / l and 30 ° C. for 30 seconds.

Example 2 The above aluminum product was
Anodizing treatment was performed using the electrode of the form shown in FIG. This electrode had a width of 700 mm, and the distance between the highest point at the center (point closest to the aluminum product) and the lowest points at both ends was 100 mm. Anodizing conditions are the same as in Example 1.

Example 3 The above aluminum product was anodized by using an electrode covered with a cover shown in FIG. This electrode had a width of 1500 mm, and an isosceles triangular notch inside the cover had a base of 200 mm and a height of 300 mm.
Anodizing conditions are the same as in Example 1.

[Prior Art 1] The above aluminum product is shown in FIG.
Anodization was performed using the electrode having the form shown in FIG. The width of this electrode was 1500 mm. Anodizing conditions are the same as in Example 1.

Table 1 shows the results obtained by comparing the characteristics of Examples 1 to 3 and Conventional Example 1 described above.

[0046]

[Table 1]

The edge concentration of the film and the amount of backing are measured by the gravimetric method.
The occurrence of burns was judged by visual evaluation and comparison.

[0048]

According to the present invention, since the concentration of the electric current on the side end portion can be suppressed, the edge concentration of the film can be suppressed and the film distribution in the width direction can be made uniform. Higher current density can be achieved. Further, since the backside of the electric current can be suppressed and the amount of the film on the back surface can be reduced, the efficiency of forming the film on the surface can be improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an anodizing device for a lithographic printing plate support, which is an example of a continuous electrolytic treatment device for a strip-shaped metal plate according to the present invention.

FIG. 2 is a plan view of electrolysis of a lithographic printing plate support which is another example of the continuous electrolytic treatment apparatus for strip-shaped metal plates according to the present invention.

3 is a sectional view taken along line AA in FIG.

FIG. 4 is a sectional view taken along line BB in FIG.

FIG. 5 is a plan view of an electrode as another example of the continuous electrolytic treatment apparatus for strip-shaped metal plates according to the present invention.

FIG. 6 is a partial plan view of an electrode portion which is another example of the continuous electrolytic treatment apparatus for strip-shaped metal plates according to the present invention.

FIG. 7 is a partial plan view of an electrode portion which is another example of the continuous electrolytic treatment apparatus for a strip-shaped metal plate according to the present invention.

FIG. 8 is a partial plan view of an electrode portion which is another example of the continuous electrolytic treatment apparatus for strip-shaped metal plates according to the present invention.

FIG. 9 is a sectional view of an anodizing tank which is another example of the continuous electrolytic treatment apparatus for strip-shaped metal plates according to the present invention.

FIG. 10 is a partial plan view of an electrode portion which is another example of the continuous electrolytic treatment apparatus for a strip-shaped metal plate according to the present invention.

FIG. 11 is a sectional view of an anodizing tank which is another example of the continuous electrolytic treatment apparatus for strip-shaped metal plates according to the present invention.

FIG. 12 is a schematic cross-sectional view of a conventional anodizing device for a lithographic printing plate support.

FIG. 13 is a plan view of an electrode of a conventional anodizing device for a lithographic printing plate support.

[Explanation of symbols]

 8, 11, 18, 22, 22, 25, 27 ... Electrodes 9, 12 ... Wide electrode section 10, 13 ... Narrow electrode section 16 ... Notches 15, 19, 23 ... Masking plate 20 ... Hole 24 ... Notch

Claims (3)

[Claims] 1. An apparatus having an electrolytic solution and an electrode provided in the electrolytic solution, wherein a strip-shaped metal plate is run in the electrolytic solution to electrolytically treat the strip-shaped metal plate, and a current density is about 5 A / An electrolytic treatment apparatus characterized in that the effective area of at least a part of the electrodes exceeding dm ² is made smaller than the effective area of the electrodes whose current density does not exceed about 5 A / dm ^2. At least a portion of the width of 2. A current density exceeds about 5A / dm ² electrode is smaller than the width of the width and the strip metal plate electrode current density does not exceed about 5A / dm ² The continuous electrolytic treatment apparatus according to claim 1. 3. An apparatus comprising an electrolytic solution and an electrode provided in the electrolytic solution, wherein a strip-shaped metal plate is run in the electrolytic solution to electrolytically treat the strip-shaped metal plate, and the current density is about 5 A / dm ²
At least a part of the electrode exceeding the distance is formed so that the distance from the strip-shaped metal plate becomes longer toward the side end in the width direction of the strip-shaped metal plate.