JPH01252800A - Electrolytic treatment equipment - Google Patents

Abstract

PURPOSE:To uniformly perform electrolytic etching treatment by specifying the length of a web of each electrode in its progressional direction at the electrode part in an electrolytic cell in which alternating waveform current is utilized and the metallic web is continuously subjected to electrolytic etching treatment. CONSTITUTION:In an electrolytic cell in which a metallic web is continuously subjected to electrolytic etching treatment by alternating waveform current, when length of the web of each electrode in its progressional direction at the electrode part is defined as (l) and the transferring velocity of the metallic web is defined as V and the frequency of alternating waveform current is defined as F, l>=V/F is satisfied. Furthermore a soft starting zone for performing low current density treatment is preferably provided to the inlet part of the metallic web. Thereby electrolytic etching treatment is uniformly performed without unevenness and continuous electrolytic treatment good in finished quality is enabled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a continuous electrolytic treatment tank that can perform electrolytic etching treatment with excellent uniformity when continuously performing electrolytic etching treatment on a metal web using alternating waveform current. This is what we are trying to provide.

[Conventional technology]

Electrolytic etching methods for the surfaces of aluminum, iron, etc. have been widely put into practical use, and alternating waveform currents are commonly used to improve the required quality and reaction efficiency. For example, in Japanese Patent Publication No. 56-19280, by using an alternating waveform voltage applied so that the anode special voltage is larger than the cathode special voltage in the electrolytic etching treatment of an aluminum plate, the surface roughness is excellent as an offset printing plate support. 9 Normal electrolytic etching treatment is performed in an acidic electrolytic bath such as 1 to 5% nitric acid or hydrochloric acid with a flow density of 10 to 100 A/dn? It will be held in When using an alternating waveform current, for example when using an aluminum plate as the metal web, during the anodic period A l ”→Aj
l! A dissolution reaction of +'3e occurs, and during the period of the cathode) (-)-6-+ -)1, ↑, and AJ2"+30H
→Ae At the same time as the hydrogen gas generation reaction of (0H)3, a smut generation reaction of aluminum hydroxide occurs on the aluminum plate. These reactions occur alternately depending on the frequency of the power source. These basic reactions can be controlled by bath type, concentration, temperature conditions, current density,
It is generally possible to obtain the required roughened surface by controlling electrical conditions such as the amount of electricity applied.

[Problem that the invention seeks to solve]

However, when an alternating waveform current is used, there is always a difference between a part where the process starts due to the dissolution reaction and a part where the process starts due to the smut forming reaction, depending on the current cycle when the metal web is introduced into the electrolytic cell. These differences naturally occur depending on the frequency of the power supply. For example, the processing speed is 50 m/min and the power frequency is 2H.
z, the difference occurs at a pitch of 41.7 cm in the longitudinal direction of the metal web. This difference is extremely important when excellent treated surface uniformity is required. That is, the difference in reaction at the start point may result in a non-uniform treated surface even after the treatment is completed.

Considering the mechanism by which these non-uniformities occur, it is natural that the higher the current density and the higher the processing speed, the stronger the degree of non-uniformity becomes. However, from the viewpoint of mass production, high processing speed and high current density processing are desired, and manufacturing is performed under conditions where this non-uniformity is likely to occur.

In addition, the length l of the electrode part, the traveling speed of the metal web V,
If 1<V/F, where F is the frequency of the alternating waveform current, the electrolytic treatment will not be performed uniformly in the running direction of the metal web.

The purpose of the present invention is to solve the conventional drawbacks in an electrolytic bath for continuously electrolytically etching a metal web.
It is an object of the present invention to provide an electrolytic processing apparatus that eliminates differences in reactions at the start point, eliminates non-uniformity of electrolytic etching processing, and is capable of stably performing continuous processing.

Means and operation for solving problem C] As a result of various studies, the present inventors have discovered that, in an electrolytic bath that continuously performs electrolytic etching treatment on a metal web using an alternating waveform current, one electrode in the electrode section The length of the web in the direction of travel per
When V is the moving speed of the metal web and F is the frequency of the alternating waveform current, by setting l≧V/F, it is more preferable to provide a soft start zone for low current density treatment at the entrance portion of the metal web. It has been discovered that by doing so, electrolytic etching can be performed uniformly and evenly.

That is, in performing electrolytic etching treatment using an alternating waveform current, the present invention sets the length ε of the electrode portion in the web traveling direction per electrode to be equal to or more than V/F, and applies low current density treatment to the entrance portion of the metal web. This is an electrolytic treatment apparatus characterized by providing a soft start zone for performing electrolytic treatment.

In the present invention, the length p of each electrode in the web traveling direction of the electrode portion satisfies l≧V/F, where V is the moving speed of the metal web and F is the frequency of the alternating waveform current. If it is necessary to divide the length 2 of one electrode into less than V/F due to restrictions in electrode manufacturing or electrolytic cell manufacturing, the electrode must be manufactured in parts and the I made it in parts! It is also possible to arrange the electrodes consecutively and make the total length of each continuous electrode equal to or greater than V/F.

The length 2 of the electrode may be at least V/F, but preferably at least twice V/F, which makes it possible to obtain a more uniform electrolytically etched surface.

The reason for this is that an anode period and a cathode period always occur in each electrode, that is, a dissolution reaction must occur, and there is no electrode that only undergoes a smut generation reaction, so that non-uniformity is prevented. That's what I do.

As for the material of the electrode, any material normally used for AC electrodes can be used.

In addition, for the purpose of preventing dissolution of AC electrodes, for example, carbon, as seen in Japanese Patent Application Laid-open No. 60-56099,
A supplementary anode electrode may also be used.

Furthermore, conductor chloride may be used instead of the auxiliary anode electrode.

In the present invention, providing a soft start zone for performing low current density treatment at the inlet portion of the metal web means that the electrode of the soft start zone faces the surface facing the metal web, as described in Japanese Patent Application No. 173674/1983. This refers to creating a soft start zone by cutting diagonally so that the length is shortened, and by bringing the cut surface into direct contact with the electrolyte. Of course, the soft start effect may be further enhanced by connecting a resistor or a coil in series to the lead wire to which the soft start zone electrode is connected. This substantially eliminates defects caused by differences in initial reactions.

As an electrolytic cell, No. 1 of JP-A No. 60-56099 is used.
Well-known structures such as a flat type as shown in the figure and a radial type as shown in FIG. 2 can be used.

The length and current distribution of the soft start zone can be arbitrarily set as required, but it is preferable that the length be equal to or greater than V/F. Preferably, the current distribution gradually decreases toward the inlet.

In carrying out the present invention, a contact power supply method using a conductor roll or a liquid power supply method may be used as a power supply method.

〔Example〕

EXAMPLES Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

Comparative Example-1 In the apparatus shown in Figure 2, the thickness was 0 under the following processing conditions.
．． JIS 3003-1, Fil 300 mm
114 aluminum web was subjected to continuous electrolytic etching treatment.

Processing conditions Processing speed 40m/win Electrolyte 1.5% nitric acid 45°C current waveform
Rectangular alternating waveform current frequency 2Hz Current density 80A/d Electrode length ffi=IQcm Number of electrodes 42 Electrode spacing 20mm Distance between aluminum nibs and electrodes 101WI11 As a result, the aluminum web is roughly perpendicular to the direction of travel. Non-uniformity of the planarized surface occurred. The honeycomb-like surface with a diameter of 2 μm was divided into a portion where circular pits with a diameter of 5 to 10 μm were scattered and a honeycomb-like surface with a diameter of 2 μm.

Example-1 Using the apparatus shown in FIG. 1, a thickness of 0.
JIS 3003- with 3 eaves and width 300m+n! (14
Continuous electrolytic etching treatment of aluminum web was performed.

Processing conditions Processing speed 40m/l1in Electrolyte 1.5% nitric acid 45°C current waveform
Square wave alternating waveform Current frequency: 2Hz Current density: 80 A/dn (Length of electrode: l=70cm Number of electrodes: 6 Electrode spacing: 20 mm Spacing between aluminum nib and electrode: 10 mm At this time, the length β of the soft start zone MS is 70c
m, and the average single flow density in this part is 10A/drr
The resistor was adjusted so that f. The spacing between the soft start zone electrode and the aluminum web was 30 strokes at the soft start zone entrance and IOM at the soft start zone exit.

As a result, a roughened surface with excellent uniformity was obtained as an offset printing plate support. Honeycomb-shaped pits with a diameter of 2 μm were uniformly obtained on the front surface.

(Effects of the Invention) Using the apparatus of the present invention enables continuous electrolytic treatment with good finish quality, and the effect is particularly remarkable in the low frequency range of 0.1 to 5 Hz.

By improving the finished quality, the commercial value of the metal web to be processed can be further increased.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the structure of an electrolytic treatment apparatus according to the present invention. FIG. 2 is a side view showing an example of a conventional continuous electrolytic treatment apparatus.

Claims (2)

[Claims] (1) In an electrolytic bath that continuously performs electrolytic etching treatment on a metal web using an alternating waveform current, the length l in the web traveling direction per electrode of the electrode part is the moving speed of the metal web, V, and the alternating waveform An electrolytic treatment apparatus characterized in that, where F is the frequency of a waveform current, l≧V/F. (2) The electrolytic treatment apparatus according to claim 1, wherein the electrode at the entrance of the metal web to the electrolytic cell is a soft start zone for performing low current density treatment.