JPH03240998A - Method for continuously coloring titanium coil - Google Patents

Abstract

PURPOSE:To effectively inhibit the occurrence of ununiformity in color due to gas generated by a reaction by uncoiling and travelling a Ti coil, which is then introduced into an electrolytic bath and brought into contact with an immersed roll after the lapse of a specified time. CONSTITUTION:When a Ti coil is continuously colored by anodic oxidation, it is uncoiled, travelled, introduced into an electrolytic bath and brought into contact with an immersed roll after the lapse of >=3sec. At least the surface of the roll is made of an electrically nonconductive material as required. The Ti coil can uniformly and continuously be colored by stable work.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for continuously and uniformly coloring a titanium coil without causing color unevenness.

<Prior art and its problems> In recent years, with the trend toward luxury in various fields, there has been a noticeable trend of applying colored titanium plates to interior materials and decorative items of buildings.

By the way, one of the methods for coloring titanium (pure titanium or titanium alloy) material used for such purposes is F"
A method of forming an oxide film on a surface that gives a color appearance through light interference is known, and generally, the method involves forming the oxide film by anodic electrolysis in an aqueous solution of phosphoric acid or phosphate. (anodic oxidation method) is used. However, conventional anodic oxidation methods tend to cause color unevenness in colored titanium materials, and it is extremely difficult to suppress color unevenness to an inconspicuous level, especially for materials with large surfaces such as architectural boards. A point had been made.

Therefore, in order to solve the above-mentioned problems that were pointed out in the conventional "method for producing colored titanium materials by anodizing", the present inventors first conducted "anodic electrolysis in a molten nitrate or dichromate". A patent application was filed in 1983 for the method of oxidizing titanium to produce color.
It was proposed as No.-325249. This method is suitable for producing colored titanium materials with a large surface area, such as interior materials for buildings, because the resulting product has very little color unevenness and can be colored in a wide variety of colors. It was a tool that held great promise.

Separately, the inventors have also stated that ``In particular, when a coiled titanium material is continuously anodic electrolyzed in molten salt to produce continuous color, abnormal oxidation may occur on the surface or deformation of the plate material. The company also found out that ``the titanium coil is energized by the conductor roll, and the titanium coil penetrates into the molten salt from the conductor roll.'' They also proposed to avoid the above problem by setting the distance to a point to a value that conforms to specific rules (Japanese Patent Application No. 1253472).

As described above, a stable mass production system for colored titanium plates with excellent appearance and shape was being established through several proposals made by the present inventors, but studies have continued from various viewpoints through actual operation. The inventors concluded that, ``Even if we carry out continuous coloring operations for titanium coils by anodizing under conditions that are thought to be the best that have been confirmed so far, when product quality is evaluated using stricter standards, They concluded that there is room for further improvement in terms of uniform coloring.

For these reasons, the inventors of the present invention went back to the basics and decided to develop a "continuous coloring operation for titanium coils by anodic oxidation."
When we re-washed the uniform coloration inhibiting factor, the following new facts were discovered.

That is, in order to continuously anodize the titanium coil, the first
As shown in the figure, it is necessary to immerse the titanium coil into the electrolytic treatment bath using a ``dipping roll,'' but normally in such equipment, the coil is immersed into the electrolytic bath almost at the same time. One side is set in contact with the dipping roll.

By the way, for example, if we use a "melt nitrate" as an electrolytic bath, when electrolysis is carried out using titanium as an anode in the electrolytic bath, gas is observed to be generated from the surface of the titanium. This is presumed to be because titanium is oxidized to produce titanium dioxide according to the formula % formula % (11), and at the same time, nitrate ions are decomposed to produce nitrogen dioxide gas. However, in Fig. When continuous anodic oxidation treatment is performed in the manner shown, one side of the titanium coil (where the reaction of formula 11 occurs most intensely) will be in contact with the dipping roll, so the generated gas will form bubbles and form a bond with the titanium coil. and the immersion roll, which prevents the reaction from proceeding smoothly and causes uneven color.

Furthermore, in this case, the gas generated and accumulated between the titanium coil and the dipping roll becomes large bubbles and is discharged from the end face of the titanium coil, which causes color unevenness on the surface that is not in contact with the dipping roll. Easy to occur.

This phenomenon occurs not only in anodization carried out in an electrolytic bath consisting of a ``nitrate melt,'' but also in anodization carried out in an aqueous solution, which has conventionally been carried out in boat fishing. That is, gas generation is observed on the titanium surface even during anodic oxidation of titanium in an aqueous solution, and this is presumed to be due to the following reaction.

Ti+60H =TiO2+ 3 HzO+'AOt+ 6 e-...
・(2J〈Means for solving the problem〉) Having obtained the above-mentioned new knowledge, the inventors of the present invention sought a means to eliminate the causes of color unevenness and stably manufacture colored titanium coil products of higher quality. As a result of repeated research, (al) The reaction in equation (1) above occurs on the surface of titanium, so once the surface of titanium is covered with Ti0z, the reaction becomes difficult to proceed any further.In reality, the reaction takes 3 seconds. The process progresses rapidly and almost ends within 5 seconds, and no further growth of the Ti0z film is observed.
The reaction of formula (2) follows almost the same process. Therefore, when continuously coloring a titanium coil by anodic oxidation, it is necessary to take at least 3 seconds (preferably 5 seconds or more) from the time the titanium coil enters the electrolytic bath until it contacts the dipping roll. By doing so, it is possible to effectively determine the color unevenness caused by the gas generated by the reaction.

(bl) Furthermore, if the material of the dipping roll is conductive, such as Ti, there is a risk that electrolysis will occur on the surface of the dipping roll, causing color unevenness in the product, and a large electrolytic current will flow. Although it is economically disadvantageous, we were able to obtain the knowledge that if the above-mentioned immersion roll were made non-conductive, such adverse effects could be completely eliminated, and the production of high-quality products would be further stabilized. .

The present invention was made based on the above-mentioned findings, etc. ``When titanium coils are continuously anodized and colored by anodic electrolysis, each part of the traveling titanium coil penetrates into the electrolytic bath. Either perform the anodizing treatment while maintaining a time margin of 3 seconds or more between the time of contact with the dipping roll, or
Alternatively, by applying a dipping roll whose surface is at least made of a non-conductive material and performing anodizing treatment, it is possible to continuously and stably produce high-quality colored titanium coil products with minimal color unevenness. It is characterized by the fact that it has been made easy to manufacture.

Here, "titanium coil" refers to pure titanium coil as well as
It is a general term that includes titanium alloy coils, and it goes without saying that the type of "electrolytic bath" does not matter whether it is a molten salt or an aqueous solution.

A commonly used "non-conductive immersion roll" can be realized by composing the surface or the entire surface of the roll with a non-conductive material, but there are no particular restrictions on the type of non-conductive pierce. However, if the electrolytic bath is a molten salt, it is better to make the non-conductive immersion roll, for example, from ceramics (alumina, etc.).

As explained earlier, the reason why we specifically limited the time allowance from when each part of the traveling titanium coil enters the electrolytic bath to when it comes into contact with the dipping roll to 3 seconds or more is as explained above. , the above formula (1) or (2) that occurs on the titanium surface.
Most of the reaction in the equation proceeds rapidly by the time 3 seconds have passed, but when most of the titanium surface is covered with TiO2 (i.e., after 3 seconds have passed), the reaction becomes extremely slow. This is because gas generation is drastically reduced and color unevenness is less likely to occur.

However, since the reaction of formula (11) or formula (2) is almost completed in 5 seconds or more, it is preferable to allow the above-mentioned "time margin" to be 5 seconds or more if possible.

It is appropriate to take the above-mentioned "time margin" by means as shown in FIG. 2, for example.

That is, Fig. 2 fa) shows the conventional method of immersing a titanium coil in an electrolytic bath, but this method can be changed to Fig. 2 (b) or Fig. 2 (
By simply making improvements like C), you can easily get the necessary time margin. In other words, the method shown in Fig. 2 (b) is a method that reduces the angle of entry of the titanium coil into the electrolytic bath, and the method shown in Fig. 2 (C) is a method in which the immersion roll is placed deep from the surface of the electrolytic bath. Both methods can easily lengthen the time from when the titanium coil enters the electrolytic bath until it comes into contact with the dipping roll.

Next, the effects of the present invention will be explained in more detail with reference to Examples.

<Example> Pure titanium coil (JIS
Type 1, 2B specification) was pre-pickled in a 10% HtJ aqueous solution at 50°C, and then subjected to a coloring test by continuous anodic oxidation.

Step 3 shown in Figure 2 above is used to immerse the titanium coil in the electrolytic bath.
A seed method was applied. Of these, Figure 2 (al is the conventional method, Figure 2 (b) and Figure 2 (C) are the methods in which the titanium coil is immersed in the electrolytic bath to the time it comes into contact with the dipping roll is lengthened. As mentioned above, this is an improved method.

The following two types of electrolytic baths were used.

(A) A molten salt made by mixing KNO and NaN0z in a weight ratio of 1=1.

(B) Hondori 101L (Saraji) 5% Na5POa aqueous solution.

In addition, the line speed was adjusted so that the total processing time was 15 seconds.

Here, although the color tone of the surface obtained by anodic oxidation varies depending on the electrolytic voltage, in this example, 0 indicates that the surface is colored blue or pink.

The results obtained from these tests are shown in Table 1.

As is clear from the results shown in Table 1, titanium coils colored according to the conditions specified in the present invention have little color unevenness on both sides, whereas the conventional method (before improvement) It can be seen that color unevenness occurs more frequently on the surface that is in contact with the surface.

In addition, apart from this, coloring tests to gold, green, and other tones were also conducted, and similar results were obtained in both cases.

Summary of Effects> As explained above, the present invention brings about industrially useful effects such as being able to uniformly and continuously color titanium coils without color unevenness under stable operation.

FIG. 1 is a conceptual diagram illustrating a continuous coloring method for titanium coils by anodic oxidation.

Figure 2 shows the titanium coil dipping method used when titanium coils are continuously colored by anodic oxidation. Figure 2 (a) shows the conventional method, Figure 2 (b) and Figure 2 ( C
) indicate improvement methods.

Claims (2)

[Claims] (1) When continuously anodizing and coloring titanium coils by anodic electrolysis, each part of the traveling titanium coil is immersed in the electrolytic bath until it comes into contact with the dipping roll.
A continuous coloring method for titanium coils, which is characterized by carrying out anodizing treatment while maintaining a time margin of more than seconds. (2) The method for continuously coloring a titanium coil according to claim 1, wherein at least the surface of the dipping roll is made of a non-conductive material.