JPS6026840B2 - Electrolytic coloring method for Al or Al gold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is capable of stably and uniformly processing anodized A-alloy or A-alloy without the need for complicated process margin control.
It relates to a method of electrolytically coloring the color tones ranging from bronze to black.

As a method for coloring A or an alloy with A, an electrolytic coloring method is widely adopted in which the material is anodized and then subjected to direct current or alternating current electrolysis. In this case, depending on the desired color tone, electrolytic coloring with Ni salt and various other metal salts added is used. For example, to obtain a bronze color tone, Ni, Co, Sn salts, etc. are added. Those that do are commonly adopted. In this case, in particular, the presence of stannous ions (SnH) in the coating was essential for improving coloring speed, coloring spreadability, uniform coloring, etc. In this way, the presence of stannous ions in the coloring bath during electrolytic coloring of A or A-ta alloys makes it possible to easily obtain coloring in a range of colors from bronze to black even by ordinary alternating current electrolytic coloring methods. However, on the other hand, the stannous ions in colored liquids lack stability and change into stannous ions in a relatively short time, which then undergoes hydrolysis. There was also the disadvantage that insoluble precipitates were likely to form.

In other words, the fact that stannous ions tend to form insoluble precipitates means that the concentration of stannous ions in the coloring agent necessary for coloring decreases in a short period of time, causing a change in the coloring state, and A. This results in a lack of uniformity in the color tone of the product material, and also leads to uneven coloring, uneven coloring, and non-uniform coloring. Furthermore, the turbid state of the colored bath due to the hydrolyzed precipitates of Sn ions becomes more significant as the precipitate concentration gradually increases, and this affects the colored state. Not only is this a serious hindrance to operation, but the loss of Sn due to Sn precipitates cannot be ignored from a medical standpoint. In the past, attempts have been made to add organic acids such as cresol sulfonic acid and phenolsulfonic acid to improve the stability of stannous ions in such electrolytic coloring baths, but this has achieved some success. However, it has not yet been fully satisfactory industrially.

From the above-mentioned viewpoint, the present inventors have solved various problems in the electrolytic coloring method for A-type or A-type alloys that uses a coloring agent containing stannous ions, and have solved the various problems in the electrolytic coloring method for A-type or A-type alloys, which uses a coloring agent containing stannous ions. In order to find an electrolytic coloring method that can stably obtain uniformly colored A-so products without deterioration, uneven coloring, or color variation, we are particularly searching for a method for stabilizing the stannous ion in colored pigments. As a result of repeated research, it has been found that pyrogallol [C64(OH)3], i.e., its isomer phloroglucin: ・Gachi○ has outstanding effects as a tin stabilizer, and it has been found that pyrogallol [C64(OH)3], and its isomer phloroglucin: If one or both of pyrogallol and phloroglucin is contained in the aqueous solution, and the secondary electrolytic coloring treatment of A or A-alloy is performed in this aqueous solution, special processing tolerance management is required. They found that it is possible to obtain a colored film with a stable and uniform color tone over a long period of time.

Although the mechanism of action of pyrogallol and phloroglucin is not necessarily clear, it is thought to be as follows.

In other words, stannous ions are easily oxidized by dissolved oxygen in an acidic coloring bath at a PHI level, and 1-hydrolysis proceeds to produce precipitates such as basic salts and metastannic acid, but when pyrogallol and phloroglucin are added, By doing so, the deoxidation/reduction reaction of dissolved oxygen in the bath proceeds preferentially, and this suppresses the oxidation of stannous ions. It should be noted that even if the amount of pyrogallol or phloroglucin added is as small as 0.3%, it will not be as effective as the conventionally known hydrolysis inhibitors.
Considering the fact that the effect lasts for a long time, it is thought that there are complex reactions that cannot be explained only by the deoxidizing effect of dissolved oxygen as described above. Therefore, the present invention has been made based on the above findings, and is based on the fact that anodized A-type or A-type alloy is treated with a stannous salt and one or two of pyrogallol and phloroglucin. It is characterized in that by electrolytically coloring in a coloring bath with added color, a uniform coloring effect can be maintained over a long period of time without requiring special tolerance control. The coloring composition in the electrolytic coloring method of this invention is, for example, NiS0418.
LO: 502 noc, SnS04:0 evening/evening, sun 2S04
Pyrogallol and It is made by adding one or two types of phloroglucin, and the amount of the stannous ion stabilizer such as pyrogallol is preferably 0.02 to 10 t/t, particularly 0.3 to 10 d/t. One evening/that range is optimal.

That is, the amount of addition of this pyrogallol etc. is 0.02 evening/day.
If the amount is less than that, the effect as a stannous ion stabilizer may not be fully exhibited, and if it is added in excess of 10 times a day, no further improvement in the effect will be obtained and there will be a pharmaceutical disadvantage. This is because it invites The appropriate Sn concentration in the colored liquid medium used in the method of this invention is 1 to 10 Tanok, which is higher than the Sn concentration of the tinned salt commonly used in the past.
Although the Sn concentration is the same as that of Sn concentration, and the conventional composition can be used as is, good results are obtained especially at the Sn concentration of 5 to 10 days.

Further, as the electrolytic conditions, known methods and conditions for alternating current electrolysis or direct current electrolysis can be used as they are.

For example, electrolysis current: 0.1-0. Pine/dwa (voltage 10
With alternating current electrolysis for 1 to 15 minutes at a voltage of ~15 V), a color ranging from bronze to black can be easily obtained. Now,
There is a slight difference in performance as a Sn stabilizer between pyrogallol and phloroglucin, which are Sn stabilizers, with pyrogallol showing a superior effect. Although phloroglucin has a relatively weak effect as a stabilizer, it can provide sufficiently superior effects compared to conventionally known stabilizers. However, 1,2,4benzenetriol, which is an isomer of the same pyrogallol, has slightly different properties and weak performance as a Sn stabilizer, so it cannot be used as a colored stabilizer containing stannous ions. It's not appropriate.

Next, the present invention will be explained using examples and comparing with comparative examples.

Example 1 A sulfuric acid acidic solution of stannous sulfate (SnS04) with a Sn concentration of 6.0 mm/sleeve and a pH of 1.0 was prepared, and immediately after that,
The tin salt was divided into 1 unit, and the tin stabilizer shown in Table 1 was added to each of the 8 units and left to stand, and the progress of hydrolysis of the tin salt over time was compared and studied.

Moreover, for each, the tin ion concentration in the solution and the coloring state in electrolytic coloring after one month had passed were compared. These results are also shown in Table 1. The results shown in Table 1 also show that in the method of the present invention, which uses a colored solution containing pyrogallol as a Sn stabilizer, the solution becomes slightly cloudy even after one month, and there is almost no hydrolysis. It can be seen that the addition of a small amount of 0.3 hours/day is extremely effective as a stabilizer.

It is also clear that the tin ion concentration in the solution, which was initially 6.0 m/m, has decreased only slightly to 5.90 m/m. Also, when using a color bath containing phloroglucin, which is an isomer of pyrogallol, as shown in the example shown in Test No. 2 in Table 1,
This shows the second best results when the above-mentioned pyrogallol is added.

Table 1 (In Table 1, ◎……Solution almost transparent, ○……The solution becomes slightly cloudy. △……Solution turbidity, slight precipitation, x... Solution cloudiness, precipitation, XX......solution cloudy, precipitate deposited).

On the other hand, the stabilizers used as cresol sulfonic acid, etc., had a small amount of addition of 0.3 m/m, and had a weak hydrolysis prevention effect, and after a few days, The solution became cloudy due to the basic tin salt, and the formation and accumulation of precipitates was observed, and after one month, the concentration of stannous ions in the solution decreased to less than half, and it was clear that most of the Sn had precipitated. It is.

In addition, a comparison of the colorability by electrolytic coloring was conducted using a 1100mm aluminum plate with a width of 5 m, a length of 10 m, and a thickness of 1 sail. AC electrolysis was carried out for 10 minutes using IW in a state where the electrolysis was carried out. As shown in Table 1, the method of the present invention uniformly colored both surfaces of the aluminum plate black, and no color unevenness was observed, whereas the method shown as a comparative example In this case, the color tone remained amber or bronze, and it was not enough to achieve black coloration, and unevenness and color variations were observed. From the above results, the method of the present invention using a colored compound containing pyrogallol or phloroglucin not only maintains the stability of the stannous ion in the colored compound over a long period of time, but also
It is clear that the coloring effect is also very good. Furthermore, apart from this, the remaining 3 units of the 11 units of sulfuric acid acidic solution that were previously divided were shown to be different over time when pyrogallol was added at different concentrations as shown in Table 2 and left to stand. (Note) The symbols indicating the degree of turbidity are the same as those shown in Table 1.

A comparative study was made of the progress of hydrolysis of tin salts according to Table 2.

Furthermore, for each, the tin ion concentration in the solution and the coloring state in electrolytic coloring after one month had passed were also compared. The results are also shown in Table 2. The results shown in Table 2 show that the amount of Sn stabilizer such as pyrogallol added in the electrolytic coloring method of the present invention is preferably 0.02 to 1.
0 evening/suggests that the range is appropriate.

Example 2 Ratio S04:300 Tano Evening, Sun 2C204:3 Evening/So, A
10 days: 5 evenings/ Using the sulfuric acid alumite grade for 10 nights at 0°C, 2. */d 5052 material (surface area 1d pillow) was hard alumite treated (film thickness 30mm) at that current density for 40 minutes, washed with water and other prescribed treatments, and then pyrogallol was added as a tin stabilizer and colored with the following composition. Coloring treatment was performed by immersing it in water.

NiS04・Fine 20:50 evening/evening, SnS〇4:10 evening/evening, Sun2S04:5 evening/evening (amount that makes PHI.0), pyrogallol; 0.3 evening/so.

The coloring is at room temperature, in the state of Inberra, AC 15V.
Secondary electrolytic coloring of ×1 enemy (counter electrode: S-keiyu) was performed to make it black.

The color changed from amber to black within a few minutes of the secondary electrolytic treatment, and after 10 minutes, it had a nearly jet black finish, and the colorability was extremely good. Aluminum treated material (1100 material,
3003 village, 606 nail material, etc.) and alumite treatment conditions, a total of 200 coloring treatments were performed over a period of 3 months. The same bath was used from the beginning until 3 months later, and the stability of the coloring was extremely good, and the coloring bath remained clean or slightly cloudy throughout.
No formal coloring was necessary. Furthermore, in a similar coloring process, cresol sulfonic acid was used as a tin stabilizer 10/20 days, but after a day or two, the coloring bath became cloudy due to the formation of basic tin salts, and some precipitates were deposited due to static staining. As a result, it was necessary to pass the liquid through an oven.

As mentioned above, according to the method of the present invention, at low cost,
Easily and reliably prevents the hydrolysis of stannous ions in electrolytic coloring baths containing stannous salts, eliminating the need for complicated margin control and ensuring no uneven coloring or color variation even during long-term operations. Industrially useful effects are brought about, such as the ability to stably supply uniformly colored A-so products.

Claims (1)

[Claims] 1. Al or Al alloy which is characterized by electrolytically coloring anodized Al or Al alloy in a coloring bath to which stannous salt and one or more of pyrogallol and phloroglucin are added. electrolytic coloring method.