JPS5815559B2 - How to color aluminum or aluminum alloy shapes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an aluminum or aluminum alloy shaped material (
The present invention relates to a method for coloring an aluminum profile (hereinafter simply referred to as an aluminum profile).

Conventionally, when electrolytically coloring an aluminum shape, the shape was
Generally, it was attached to a frame or two transport frames.

However, this method has the disadvantage that the processing amount is naturally limited and cannot be processed in large quantities, and furthermore, it has not been possible to obtain beautiful aluminum shapes that are uniform, dark, and evenly colored.

The present invention has been made in view of the above-mentioned drawbacks of the conventional art.
By simultaneously dipping and electrolytically coloring, it is possible to simultaneously process large quantities of aluminum shapes and obtain uniformly colored aluminum shapes.
The present invention aims to provide a method for coloring aluminum shapes that can solve problems associated with the increase in size of equipment.

That is, the present invention simultaneously transports four transport frames formed by vertically suspending a large number of aluminum or aluminum alloy shaped materials with anodized coatings in rows, and simultaneously transports four transport frames that are suspended from the four transport frames. A large number of molds were simultaneously immersed in an electrolytic bath containing a metal salt, and electrodes were placed at the left, right, inner, outer, and center positions of the four frames, and two rows of molds facing each other were positioned between the two electrodes. The first and third and second and fourth of the four frames are each made into one energizing unit, and these two energizing units are not energized at the same time (each energizing unit is The gist of the method is to sequentially apply anodic direct current electrolysis at a voltage of 15 to 25 V, alternating current electrolysis at a voltage of 10 to 25 V, and cathodic direct current electrolysis at a voltage of 15 to 30 V, and electrolytically color the product.

In the present invention, four frames of a transport frame in which aluminum shapes with anodized coatings are hung vertically in multiple rows are simultaneously transported to an electrolytic coloring tank using, for example, a crane or a conveyor, and are simultaneously immersed in an electrolytic bath.

In the anodic oxidation treatment, an aluminum profile having a length of, for example, 6 m is electrolytically oxidized in an aqueous solution of sulfuric acid, chromic acid, oxalic acid, or the like.

Electrodes are installed in the electrolytic coloring tank, and as shown in FIG. 1, electrodes E1. In addition to arranging the electrodes E3, the electrodes E2 are arranged at the center of the four frames.

Note that it is also possible to use the tank walls as electrodes at both the left and right outer positions.

Also, electrode E1. It is also possible to install two electrodes at the center positions of the four frames so as to form a pair with E3.

It has been found that when two electrodes are installed at the position in this way, the uniformity of the colored film can be improved more than when one electrode is installed.

The first and third frames and the second and fourth frames of the four frames are each configured as one energization unit.

That is, as shown in FIG.
and A2 are electrically connected to each other to form a current-carrying unit U1,
And the second and fourth of the four frames, namely transport frames 2 and 4
The aluminum shapes A2 and A4 stacked on top of each other are electrically connected to each other to form a current-carrying unit U2.

Here, the energizing unit refers to an electrical connection relationship in which when one of the first and third units or the second and fourth unit is energized, the other one is left in a non-energized state. .

For example, in FIG. 1, the aluminum profile A1 connected to the current-carrying unit U1. A3 was first subjected to anodic DC electrolysis at a voltage of 15 to 25V, then after AC electrolysis at a voltage of 10 to 25V,
After sequentially passing cathodic DC electrolysis with a voltage of 15 to 30 V, the aluminum profile A2 is connected to the current-carrying unit U2. Similarly, A4 is sequentially subjected to electrolytic coloring treatment.

On the other hand, it is desirable for the power supply in electrolysis to be provided at the same time or for each energization unit from the viewpoint of economics and equipment simplification, but it is also possible to provide multiple power supplies for each conveyance frame.

In the figure, 5 is an electrolytic coloring bath, and 6 is an electrolytic bath containing a metal salt.

The metal salts contained in the electrolytic bath include nickel salts, cobalt salts,
One or more water-soluble salts such as copper salts, tin salts, and silver salts are used.

Depending on the type of water-soluble salt, appropriate amounts of sulfuric acid, boric acid, hydroxide metal salts such as nickel hydroxide, metal carbonate salts, ammonia, etc. are added to adjust the conductive dust and pH of the electrolytic bath.

Furthermore, additives such as citric acid, succinic acid, and tartaric acid are added as necessary.

Here, an example of a bath composition when nickel sulfate is the main component is 150 to 180 g of nickel sulfate hexahydrate.
/l, boric acid 5-50g/l.

The temperature of the electrolytic coloring bath is room temperature to 40'C1, and the pH is 2 to 5.
5, preferably 3 to 45.

As the counter electrode, aluminum or metals of the same quality throughout the country used in the electrolytic solution, such as nickel, tin, copper, etc., are used.

The surface area ratio of the electrode and mold material (opposite electrode ratio) is 2:1 to 1:50,
Preferably it is 1:5 to 1:10.

By the way, the current density and electrolysis time in anodic DC electrolysis, AC electrolysis, and cathodic DC electrolysis depend on the electrolytic bath composition, counter electrode ratio,
The maximum current density for anodic DC electrolysis is 0, although it may vary depending on the distance between the counter electrode and the processing amount of the aluminum mold material.
1 to 1.5 A/dm2, electrolysis time is 1 to 15 seconds, and maximum current density in AC electrolysis is 0.1 to 2. OA/dm2,
Electrolysis time is 1 to 30 seconds, maximum current density in cathodic DC electrolysis is 0.1 to 1.0 A/dm, electrolysis time is 30 to 24 seconds.
It is desirable to set it to 0 seconds.

Although alternating current electrolysis and cathodic direct current electrolysis are usually performed in the same electrolytic cell as anodic direct current electrolysis, it is also possible to prepare a separate electrolytic cell and use this electrolytic cell to perform alternating current electrolysis and cathodic direct current electrolysis.

When performing the three electrolytic treatments in the same electrolytic cell, a changeover switch may be provided on the power source to switch the power supply each time the electrolytic treatments are performed.

In the present invention, the electrolytic coloring treatment also has the effect of AC electrolysis,
If you are able to obtain a satisfactorily colored film but would like to obtain an even darker color, do not electrolytically color each energizing unit at the same time. Electrolytic treatment may be repeated.

In addition, when performing anodic direct current electrolysis, the present invention also provides for
Can be left in a non-energized state.

In this case, 60 seconds or more is preferable.

By incorporating this non-energized state, the uniformity of coloring can be further improved.

Further, when switching from AC electrolysis to cathodic DC electrolysis, it is possible to make the device non-energized for a certain period of time.

When alternating current electrolysis is performed in an industrially large-scale electrolytic cell, an induced current is generated, so in order to eliminate this, it is desirable to leave the cell in a non-energized state for a certain period of time.
Preferably it is 15 seconds or more.

Similarly, when switching from anodic direct current electrolysis to alternating current electrolysis, it is possible to keep the device in a non-energized state, and the non-energized time at this time is 5 seconds or more, preferably 10 seconds or more.

The present invention may sequentially apply anodic DC electrolysis, AC electrolysis, and cathode DC electrolysis to one energization unit, and then sequentially apply each of the above electrolysis to other energization units, or alternatively, one energization unit may be subjected to anodic DC electrolysis, AC electrolysis, After sequentially applying electrolysis, each of the above-mentioned similar electrolysis is sequentially applied to other current-carrying units, and then, after applying cathodic direct current electrolysis to the one current-carrying unit, similar electrolysis is applied to the other current-carrying units. Good too.

In the present invention, good results can be obtained by performing cathodic direct current electrolysis at a voltage higher than the voltage during anodic direct current electrolysis.

The aluminum shape material subjected to the electrolytic coloring treatment in this manner is subjected to a sealing treatment or painting as necessary.

According to the present invention, it is possible to obtain a uniform, dark and beautiful colored aluminum profile without uneven coloring, and this is believed to be due to the following reasons.

That is, when the entire conveyance frame is treated as one current-carrying unit and is energized simultaneously, current flows simultaneously through adjacent molds, for example, aluminum molds A1 and A2, and A3 and A4 in FIG. An electrical repulsion phenomenon occurs between the mold materials, preventing the uniformity of the resistance of the anodic oxide film, making it impossible to stabilize the current density, and also preventing the uniform adsorption of metal ions due to the repulsion of metal ions. For example, in FIG. 1, uncolored parts occur at a, b, c, and d, but in the present invention, the first and third, and the second and fourth transport frames are each one. By sequentially applying anodic direct current electrolysis, alternating current electrolysis, and cathodic direct current electrolysis to aluminum shapes that are configured as energizing units and are not adjacent to each other under predetermined conditions,
The action of removing impurities that are thought to be attached or adsorbed to the anodic oxide film, or the action of equalizing the resistance of the anodic oxide film, or, for example, the aluminum shapes A1 and A3, or A2 and A4 in FIG. 1, are electrolyzed. Therefore, in combination with the effect of preventing the non-adherent portions, the anodic oxide film is further improved, the current density is stabilized, and the distribution state of metal ions in the electrolytic bath is also uniformized. The metal or metal oxide is evenly and easily deposited into the anodic oxide film, and the amount of the deposit increases and the electrical conductivity is also significantly improved.

As a result, for example, even though the distance from the electrode is different between one side and the other side of the aluminum profile, which generally tends to cause uneven coloring, it is possible to obtain an aluminum profile that is uniformly colored without uneven coloring. it is conceivable that.

As described above, the present invention is suitable for a large-scale production system in which four transport frames are simultaneously transported and a large number of aluminum shapes are electrolytically colored, and furthermore, the present invention is suitable for a large-scale production system in which four frames of transport frames are transported simultaneously and a large number of aluminum shapes are electrolytically colored. This is an excellent coloring method that eliminates the disadvantages and allows several times the processing time compared to conventional methods, and also makes it possible to obtain beautiful aluminum shapes with a uniform and dark color.

According to the present invention, it is possible to carry out a large-scale live coloring treatment of aluminum shapes, and the coloring properties are excellent.

Further, according to the present invention, it is not affected by impurities contained in the electrolytic bath, and poor coloring can be prevented, and the tolerance range for impurities is wide.

Therefore, there is no need to strictly control the quality of water during bath preparation and pretreatment during electrolytic coloring, and there is no need to provide a large ion exchange device (this method is industrially very suitable).

Furthermore, the present invention eliminates the need for electrodes, which were conventionally provided at the very edges of a large number of molds marked on a conveying frame, in large-scale live coloring processing, and allows a uniform colored film to be obtained with a small number of electrodes. Therefore, the equipment can be kept to a minimum and the electrolysis can be carried out efficiently.

Next, examples of the present invention will be shown.

Example Four transport frames 1, 2, 3, and 4, each consisting of a large number of aluminum profiles suspended vertically in a row, were simultaneously transported using a crane, degreased, and
After performing the etching and neutralization treatments, the mold material was immersed in an anodizing tank and placed in a 180 g/l sulfuric acid solution at a current density of 1.
Direct current electrolysis was carried out under the conditions of 3A/dm'', electrolysis time of 30 minutes, and bath temperature of 20°C to form an anodic oxide film.

After washing with water, the transport frames 1, 2, 3, and 4 were simultaneously transported to an electrolytic coloring bath 5, where they were lowered and the shapes were simultaneously immersed in an electrolytic bath 6.

Electrode E1 at this time. The arrangement structure of E2 and E3 is the first
As shown in the figure.

The composition and conditions of the electrolytic bath 6 are as follows.

Nickel sulfate hexahydrate 1.50 ? /l diboric acid 50 ? /IPH'
3.7 temperature
35°C. Contains 760 ppm of sodium ions (as an example of impurities).

The transport frames 1 and 3 and 2 and 4 are electrically connected, respectively, to each energized unit U1. After configuring U2 and leaving it in a non-energized state for 5 seconds, first, DC power is supplied to the energized unit U1 and the transport frame 1,
Shapes A1. A3 was placed as an anode, and DC electrolysis was performed under conditions of a voltage of 18 V and an electrolysis time of 10 seconds.

Next, after leaving it in a non-energized state for 15 seconds, AC power was supplied to the energizing unit U1 to perform AC electrolysis under the conditions of a voltage of 20 V and an electrolysis time of 10 seconds, and then a non-energizing state for 10 seconds, and then again. After supplying DC power, the mold materials A1 and A are
3 was placed as a cathode, and DC electrolysis was performed under conditions of a voltage of 20 V and an electrolysis time of 60 seconds.

Next, the power supply connection is switched to the energizing unit U2, and the shapes A2. A4 was electrolyzed under the same conditions as above.

In addition, each current density is approximately 0.3 to 0.02 in order of each electrolysis.
A/dm2.0.8-0.6 A/dm2.0.3-0.
05A/di.

As a result, each mold material A1. A2. A3. A bronze uniform colored film was formed on A4 paper.

Further, when the sodium ion concentration was about 60 ppm, no influence appeared and no defective coloring occurred.

Comparative Example 1 A mold material on which an anodized film was formed in the same manner as in the above example was simultaneously immersed in the electrolytic bath 6 used in the above example, and the transport frames 1 and 3 and 2 and 4 were electrically connected, respectively. Each of the energizing units U1 and U2 was constructed in the same manner as in the previous embodiment.

First, DC power is supplied to the energizing unit U1 and the shape material A1 is
．． A3 was subjected to anodic DC electrolysis under conditions of a voltage of 23 V and an electrolysis time of 10 seconds, and then mold materials A1 and A3 were subjected to cathode DC electrolysis under conditions of a voltage of 20 V and an electrolysis time of 45 seconds.

Next, the power supply connection is switched to the energizing unit U2, and the shape material A2. A4
was electrolyzed under the same conditions as above.

As a result, spalling occurred and a good colored film could not be obtained.

Comparative Example 2 A mold material on which an anodized film was formed in the same manner as in the above example was simultaneously immersed in the electrolytic bath 6 used in the above example, and the transport frames 1, 2, 3, and 4 were electrically connected to each other. Connected.

Each mold material A1. A2. A3. A4 was simultaneously subjected to anodic direct current electrolysis, alternating current electrolysis, and cathodic direct current electrolysis at 10 V for 10 seconds, 5 V for 5 seconds, and 20 V for 60 seconds.

As a result, spalling and uneven coloring occurred and a good colored film could not be obtained.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of electrolytic coloring by the method of the present invention. 1.2, 3, 4...Transfer frame, 5...Electrolytic coloring tank, 6...Electrolytic bath, Ul, U2...
・・Electrification unit, A,, A2゜A3. A4... Aluminum profile, El, E2. E3... Electrode.

Claims (1)

[Claims] 1 Simultaneously conveys four frames of a transport frame formed by vertically suspending a large number of aluminum or aluminum alloy shapes with anodized coatings in rows, and simultaneously transports a large number of shapes suspended from the four transport frames. Simultaneously immersed in an electrolytic bath containing metal salts,
Electrodes are arranged at the left, right, inner and outer positions and at the center position of the four frames, so that two rows of mold members facing each other are located between the two electrodes, and the third, the second and the fourth respectively as one energizing unit,
Without energizing those two energizing units at the same time, for each energizing unit, anode DC electrolysis with a voltage of 15 to 25 V, a voltage of 10
A method for coloring aluminum or aluminum alloy shaped materials, which comprises sequentially applying alternating current electrolysis at a voltage of ~25 V and cathodic direct current electrolysis at a voltage of 15 to 30 V to electrolytically color the material.