JP2946445B2 - Continuous electrolyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In general, an aluminum support used for a lithographic printing plate is required to have excellent hydrophilicity and water retention, and therefore, its surface is finely divided by a mechanical, chemical or electrochemical method. The surface is roughened 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, anodizing treatment of a lithographic printing plate support has been disclosed in Japanese Patent Application Laid-Open No. 48-26638 and Japanese Patent Publication No. 58-2451.
No. 7, JP-A-47-18739, and the like, which are disclosed in Japanese Patent Application Laid-Open Nos. 47-18739, and this method is called a so-called submerged power supply system. As an anodizing apparatus (so-called flat type) using the submerged power supply system, for example, there is an apparatus shown in FIG.

An anodizing apparatus shown in FIG. 12 includes a power supply tank 32 for negatively charging an aluminum product 31, an anodizing tank 33 for anodizing the aluminum product 31,
An intermediate portion 34 for preventing a short circuit of current between the power supply tank 32 and the anodic oxidation treatment tank 33 is provided, and an electrolytic solution 35 is stored in the power supply tank 32 and the anodic oxidation treatment tank 33. And the power supply tank 32
The power supply electrode 36 is disposed in the electrolytic solution 35 in the anodic oxidation treatment tank 33, and the power supply electrode 36 is connected to the electrolytic electrode 37 via a DC power supply 38. Then, the electrolytic electrode 37 in the anodizing tank 33 is configured as shown in FIG.
As shown in the figure, the width is formed longer than the width of the aluminum product 31.

[0005] In such an anodizing apparatus,
The current from the DC power supply 38 flows from the power supply electrode 32 to the aluminum product 31 via the electrolytic solution 35 in the power supply tank 32, and the current flows inside the aluminum product 31 to the anodizing tank 33. As a result, the aluminum product
An anodic oxide film is formed on the surface of 31.

[0006]

In a lithographic printing plate support production line, since the size of the lithographic printing plate product is very diverse, the aluminum product to be treated is usually of 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 as to be applicable to all various aluminum products.

[0008] Therefore, in the anodizing tank, current concentrates on the side edges of the aluminum product, and the amount of oxide film on both side edges increases as compared with the central portion. Such a phenomenon is not so problematic when the supply current amount is small, but when the processing line is speeded up to improve productivity or when the amount of anodized film is increased to improve quality performance. The current density must be increased. If the current density is increased, the amount of the oxide film on the side edge of the aluminum product increases remarkably, exceeding the permissible limit in quality or the concentration of local reaction, so-called burn. A failure occurred. Therefore, it was not possible to increase the current density and to increase the speed of the processing line or increase the amount of the anodic oxide film. In addition, the equipment becomes large and the equipment cost increases.

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

[0010] The present invention is to further improve the above proposed technique, and to provide a continuous electrolytic processing apparatus capable of more efficiently performing electrolytic processing while preventing current from concentrating on side edges and sneaking to the back surface. Aim.

[0011]

Means for Solving the Problems The present invention has been made to achieve the above object, and a continuous electrolytic processing apparatus of the present invention has an electrolyte and electrodes provided in the electrolyte. Then, in an apparatus for performing an electrolytic treatment of a strip-shaped metal plate by running the strip-shaped metal plate in an electrolytic solution, an effective area of at least a part of an electrode having a current density exceeding 5 A / dm ² is reduced to 5 A / dm ^2.
It is configured to be smaller than the effective area of the electrode not exceeding 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 adverse effect of the embedding is large. In addition, since this adverse effect varies depending on various electrolysis conditions, in accordance with the variation, of the electrodes whose current density exceeds about 5 A / dm ² , the range in which the effective area is reduced (a half of the electrode, 2 / 3 part, all). The effective area is an area that contributes to the electrolytic treatment of the electrode.

[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 Means for forming a notch in at least a part of the side end of the electrode exceeding the above, and means for providing a masking plate on at least a part of the side end of the electrode having a current density exceeding about 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 thus set is appropriately set to an optimum length depending on the width of the band-shaped metal plate, the distance between the band-shaped metal plate and the electrode, and the like. For example, when the width of the band-shaped metal plate is 1000 mm and the distance between the band-shaped metal plate and the electrode is 20 mm, the range is preferably 300 to 900 mm, and particularly preferably 500 to 800 mm.

The means for forming one or more notches and holes in at least a portion of the electrode having a current density exceeding about 5 A / dm ² comprises:
For example, the side end of the electrode is formed in a continuous triangle, square, arc, or the like, or a hole is formed in the entire electrode, and the hole is reduced in size toward the side end.

In a means for providing a masking plate on at least a part of a side end of an electrode having a current density exceeding about 5 A / dm ² , the masking plate is provided between the electrode and the metal strip,
It is provided at least at a position that does not face the strip-shaped metal plate but faces 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 band-shaped metal plate, otherwise, the inner side edge of the masking plate is the side edge of the band-shaped metal plate. It is located more inside. The position of the inner side edge of this masking plate is
The width of the strip-shaped metal plate, the width of the electrode, the distance between the strip-shaped metal plate and the electrode, etc. are appropriately determined.
A range of 0 mm is preferred. If the inner side edge of the masking plate is outside the side edge of the band-shaped metal plate, it is not possible to effectively suppress the concentration of current on the side edge of the band-shaped metal plate, and the inner side end of the masking plate is From the side edge of the board toward the inside
When the distance is within 200 mm, the amount of the anodic oxide film at the side end of the strip-shaped metal plate is smaller than usual.

Such a masking plate can be provided on the surface of the electrode, and an electrode cover having a larger opening ratio at the center portion than at the side end in the width direction of the strip-shaped metal plate can be used. The electrode cover has an opening formed therein, and the opening ratio of the opening is larger at the center. For example, when the opening is circular, the central part has a large diameter and the side ends have a small diameter, or an isosceles triangle with the central part having the bottom side and the side end part having the apex.

Further, the continuous electrolysis apparatus of the present invention has an electrolytic solution and an electrode provided in the electrolytic solution, and performs an electrolytic treatment of the strip-shaped metal plate by running the strip-shaped metal plate in the electrolytic solution. Wherein at least a part of the electrode having a current density exceeding about 5 A / dm ² is formed such that a distance from the strip-shaped metal plate becomes longer toward a side end in a width direction of the strip-shaped metal plate. It is configured.

In order to increase the distance from the band-shaped metal plate toward the side end, the cross-sectional shape is formed so as to protrude toward the band-shaped metal plate toward the center. This protruding shape may be continuous or discontinuous.For example, as a continuously changing shape, there are an arc shape, an isosceles triangular shape, a parabolic shape, and the like. There is a step shape as a shape that changes to.

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

As the electrolytic solution, for example, an aqueous solution of sulfuric acid, phosphoric acid, oxalic acid or a salt thereof, or a mixed solution thereof may be used, but an optimal solution may be selected to obtain desired quality. The concentration and temperature of the electrolyte can be freely selected. As the power supply waveform, a direct current is generally used, but other than this, an optimal waveform such as an AC waveform or an AC / DC superimposed waveform can be selected to obtain a desired quality. The current density during electrolytic treatment
You can choose freely. For example, the current density may be kept 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 the anodizing apparatus is used, the anodizing apparatus can be applied to a conventionally used known anodizing apparatus (flat type). However, a supporting roller for supporting the strip-shaped metal plate and at least one of upstream and downstream of the supporting roller are provided. The present invention can also be applied to a device (radial type) having a power feeding roller that comes into contact with the provided strip-shaped metal plate and a substantially concentric electrode provided along the outer peripheral surface of the support roller.

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

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

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

After the anodizing treatment of the strip-shaped metal plate, if necessary, the sealing treatment described in JP-A-1-150583,
-141491 described hydrophilization treatment, U.S. Pat. No. 3,118,461 specification alkali metal silicate aqueous solution treatment, U.S. Pat.No. 3,860,426 specification hydrophilic cellulose containing water-soluble metal salt described in U.S. Pat. Can be implemented.

When the strip-shaped metal plate according to the present invention is used as a support for a planographic printing plate, a photosensitive layer can be provided on the surface thereof to form a photosensitive planographic printing plate. Examples of the composition of the photosensitive layer include those composed of a diazo resin, those composed of an o-quinonediazido compound, those composed of 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 current is concentrated on the side edge or goes around the back surface. This prevents the current from concentrating and sneaking around the side edge, and sufficiently supplies the current to the portion of the electrode where the current does not concentrate on the side edge or sneak onto the back surface.

An example of the continuous electrolytic processing apparatus for a strip-shaped metal plate of the present invention will be described with reference to the drawings. 1 is a schematic diagram of an anodizing apparatus for a lithographic printing plate support, FIG. 2 is a plan view of an electrolytic electrode, FIG. 3 is a cross-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, a power supply tank 1, an anodizing tank 2, an intermediate portion 3, a power supply electrode 4, an electrolytic solution 5, and a DC power supply 6 are configured in substantially the same manner as the conventional anodizing apparatus shown in FIG. The same applies to the aluminum product 7.

In FIG. 1, reference numeral 8 denotes an electrolytic electrode for anodizing an aluminum product 7;
As shown in FIG. 2, the width of the aluminum product 7 is changed stepwise along the traveling direction a. As shown in FIG. As shown in FIG. 4, it comprises a narrow electrode portion 10 which is narrower than the width of the aluminum product 7.
The current density of the wide electrode portion 9 is 5 A / dm ^2.
And the narrow electrode portion 10 is a high current density portion c having a current density of 5 A / dm ² or more.

In order to perform anodic oxidation with the above-described anodizing apparatus, a current is supplied from the DC power supply 6 to the power supply electrode 4 and the electrolytic electrode 8 in the same manner as in the prior art. An anodic oxide film is formed on the surface. At this time, in the narrow electrode portion 10, the width of the narrow electrode portion 10 is smaller than the width of the aluminum product 7, so that the current is supplied substantially uniformly to the front surface of the aluminum product 7. Also,
In the wide electrode portion 9, the current is concentrated on the side end portion of the aluminum product 7, but the current density is low, so that unevenness of the coating, burnout failure, and generation of the coating on the rear 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. 14 is a plan view of another example of an electrode. The electrode of the example shown in FIG.
11 is a wide electrode portion 12 wider than the width of the aluminum product 7.
And the narrow electrode portion 13 which is 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 cutouts and holes are formed in at least a part of an electrode having a current density exceeding about 5 A / dm ² . The electrode 15 of the example shown in FIG.
Has rectangular notches 16 formed at both ends at regular intervals.

FIGS. 7, 8 and 9 show that 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 part of a side end of an electrode exceeding dm ² .

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

The electrode 18 in the example shown in FIG. 8 is the same as the conventional one, but a masking plate 19 is fixed on the upper surface except for a part of the center of the electrode 18. 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, and the size of the holes 20 increases toward the center. Therefore, the exposed area of the electrode 18 increases toward the center.

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

FIGS. 10 and 11 show that at least a part of the electrode having a current density exceeding about 5 A / dm ² has a longer distance from the strip-shaped metal plate toward the side end in the width direction of the strip-shaped metal plate. It is sectional drawing of the anodic oxidation tank of the example formed.

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

[0040]

【Example】

An anodized strip metal plate: A long JIS 1050 aluminum strip 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 sanded with a rotating nylon brush using the Pumice 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 performed 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 an aqueous solution of 0.7% nitric acid, a rectangular wave alternating waveform having a voltage of 13 volts at the anode and a voltage of 6 volts at the cathode (power supply waveform described in Example of JP-A-52-77702) was used for electrolytic roughening for 20 seconds. The surface was washed in a 20% aqueous sulfuric acid solution and then washed with water.

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

Example 2 The above aluminum product was
Anodizing treatment was performed using an electrode having 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 point at both ends was 100 mm. The anodizing conditions are the same as in Example 1.

Example 3 The above aluminum product was anodized 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.
The anodizing conditions are the same as in Example 1.

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

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

[0046]

[Table 1]

The concentration of the edge of the film and the amount of backing are determined by the weight method.
The occurrence of burns was determined by visual evaluation and comparison.

[0048]

According to the present invention, since the current can be suppressed from concentrating on the side edge, the edge concentration of the film can be suppressed, the film distribution in the width direction can be made uniform, and the critical current density at the burn failure can be reduced. The current density can be increased to increase the current density. In addition, the amount of film on the back surface can be reduced by suppressing the backflow of the current, so that the efficiency of film formation on the front surface can be improved.

[Brief description of the drawings]

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

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

FIG. 3 is a sectional view taken along line AA in FIG. 2;

FIG. 4 is a sectional view taken along line BB in FIG. 2;

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

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

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

FIG. 9 is a partial plan view of an electrode portion which is another example of the continuous electrolytic processing apparatus for a strip-shaped metal plate according to the present invention.

FIG. 10 is a cross-sectional view of an anodic oxidation tank as another example of the continuous electrolytic processing apparatus for a strip-shaped metal plate according to the present invention.

FIG. 11 is a cross-sectional view of an anodic oxidation tank as another example of the continuous electrolytic processing apparatus for a strip-shaped metal plate according to the present invention.

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

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

[Explanation of symbols]

 8, 11, 18, 22, 25, 27 ... electrode 9, 12 ... wide electrode part 10, 13 ... narrow electrode part 16 ... notch 15, 19, 23 ... masking plate 20 ... hole 24 ... notch

Continuation of the front page (56) References JP-A-6-207299 (JP, A) JP-A-6-41785 (JP, A) JP-A-4-176899 (JP, A) , U) (58) Fields investigated (Int. Cl. ⁶ , DB name) C25D 11/04 C25D 7/06 C25D 11/00 305 C25D 21/00 C25D 21/12

Claims (3)

(57) [Claims] An apparatus for electrolytically treating a strip-shaped metal plate by running the strip-shaped metal plate in the electrolyte, comprising an electrolyte and an electrode provided in the electrolyte, wherein the current density is about 5 A / An electrolytic processing apparatus characterized in that the effective area of at least a part of the electrode exceeding dm ² is smaller than the effective area of the electrode having a current density not exceeding 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 processing apparatus according to claim 1. 3. An apparatus for electrolytically treating a strip-shaped metal plate by running the strip-shaped metal plate in the electrolyte, comprising an electrolyte and an electrode provided in the electrolyte, wherein the current density is about 5 A / dm ²
At least a part of the electrodes exceeding the width of the strip metal plate is formed so that the distance from the strip metal plate becomes longer toward the side end in the width direction of the strip metal plate.