JP4849420B2 - Method for electrolytic treatment of etching solution - Google Patents

Description

  The present invention relates to an electrolytic treatment method for an etchant containing a manganese salt as an active ingredient.

  As a method of forming an electroplated film on a resin molded body, after degreasing and etching, neutralization and pre-dip are performed as necessary, and then a colloidal solution containing a tin compound and a palladium compound is used. A general method is a method in which an electroless plating catalyst is applied, an activation treatment (accelerator treatment) is performed as necessary, and then electroless plating and electroplating are sequentially performed (Non-Patent Document 1).

  In this case, a chromic acid mixture composed of a mixture of chromium trioxide and sulfuric acid is widely used as the etching treatment liquid. However, the chromic acid mixture contains toxic hexavalent chromium and thus has an adverse effect on the working environment. In addition, in order to treat wastewater safely, it is necessary to neutralize and precipitate hexavalent chromium after reducing it to trivalent chromium ions, and complicated treatment is required for wastewater treatment. For this reason, in consideration of safety at the time of work in the field and the environmental impact of wastewater, an etching treatment liquid not containing chromic acid is desired.

  As a result of repeated research to develop an etching solution that can replace the chromic acid mixture, the present inventors have found at least one component selected from the group consisting of manganese salts, inorganic acids, and perhalogenates and perhalogenates. A novel etching solution containing an active ingredient has been found. The etching solution is a highly safe etching treatment solution that does not contain highly harmful components such as chromic acid, and forms a plating film with high adhesion when used in etching treatments for various resin molded products. can do.

However, when the etching process is continuously performed using the etching solution, the perhalogen acid and the perhalogenate are reduced to the halogen acid and the halogen acid salt, respectively. Accumulation in the layer tends to cause self-decomposition of the etching solution, and the concentration of manganese salt, perhalogenic acid, perhalogenate, etc. rapidly decreases, and the composition of the etching solution cannot be kept constant. In this way, the etching solution in which the concentration of manganese salt, perhalogen acid, perhalogenate, or the like is lowered has a reduced oxidizing action, and eventually etching cannot be continued. For this reason, it is desired to develop a method capable of extending the life of the etching solution containing the above-described manganese salt as an active ingredient by solving the problem of performance degradation due to the self-decomposition of the etching solution.
Tadao Hayashi, Masao Matsuoka, Hidemi Rope Funa; Electroplating Research Group, “Electroless Plating—Basics and Applications”, Nikkan Kogyo Shimbun (1994), pp. 133

  The present invention has been made in view of the current state of the prior art described above, and its main object is to accumulate halogen acid and / or halogen acid salt by using a novel etching solution containing the above manganese salt. In such a case, the method is to provide a method that enables continuous use for a long time by reducing the concentration.

  As a result of intensive studies to achieve the above-mentioned object, the present inventor, for the etching liquid containing the above-described manganese salt as an active ingredient, when halogen acid and / or halogen acid salt accumulates with use, It has been found that by performing anodic electrolytic oxidation treatment, the concentration of the halogen acid and the halogen acid salt can be reduced, the performance of the etching solution can be prevented from being deteriorated, and excellent etching performance can be maintained for a long time. The invention has been completed.

That is, the present invention provides the following electrolytic treatment method for an etching solution.
1. From an aqueous solution containing 20 to 1200 g / L of inorganic acid, 0.01 to 40 g / L of manganese salt, and 1 to 200 g / L of at least one component selected from the group consisting of perhalogenates and perhalogenates. An etching solution electrolytic treatment method comprising:
An anodic electrolytic oxidation treatment of an etching solution in which the concentration of a halogen acid and / or a halogen acid salt is increased by use.
2. Item 2. The method according to Item 1, wherein the etching solution in which the total concentration of the halogen acid and the halogen acid salt is 10 g / L or more is subjected to electrolytic treatment.
3. Item 3. The method according to Item 1 or 2, wherein an insoluble electrode is used as the anode.
4). The method according to any one of items 1 to 3 for performing electrolysis in the anodic current density 0.1~20A / dm ^2.
5). Item 5. The method according to any one of Items 1 to 4, wherein the anodic electrolytic oxidation treatment is performed with stirring.

  Hereinafter, the processing method of the present invention will be specifically described.

Etching solution to be treated The etching solution to be treated in the present invention is selected from the group consisting of 20 to 1200 g / L of inorganic acid, 0.01 to 40 g / L of manganese salt, and perhalogen acid and perhalogenate. It consists of an aqueous solution containing 1 to 200 g / L of at least one component. The etching solution is an etching treatment solution that can replace a chromic acid mixed solution that can form a plating film having good adhesion to various resin molded bodies such as ABS resin. It is a novel etching solution that is high and easy to treat waste water.

  Among the active ingredients in the etching solution, inorganic acids include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, boric acid, carbonic acid, sulfurous acid, nitrous acid, phosphorous acid, boric acid, hydrogen peroxide, perchloric acid, etc. Can be used. Of these, sulfuric acid, hydrochloric acid and the like are particularly preferable. These inorganic acids can be used singly or in combination of two or more. The content of the inorganic acid is about 20 to 1200 g / L, preferably about 300 to 1000 g / L.

  Of the effective components in the etching solution, permanganate is particularly preferable as the manganese salt. The permanganate may be a salt in an aqueous solution, and specific examples thereof include sodium permanganate and potassium permanganate. Manganese salts can be used singly or in combination of two or more. The manganese salt content is about 0.01 to 40 g / L, preferably about 0.1 to 10 g / L.

  Among the active ingredients in the etching solution, examples of perhalogen acids include perchloric acid, perbromic acid, and periodic acid. As the perhalogenate, the above-mentioned water-soluble salt of perhalogen acid can be used, and for example, sodium perhalogenate, potassium perhalogenate, or the like can be used. Perhalogenic acid and perhalogenate can be used singly or in combination of two or more.

  The content of at least one component selected from the group consisting of perhalogenic acid and perhalogenate is about 1 to 200 g / L, preferably about 10 to 100 g / L.

Electrolytic treatment method of etching solution When the above etching solution is subjected to etching treatment for a long period of time, perhalogen acid and / or perhalogenate in the etchant is reduced to produce halogen acid and / or halogenate, When accumulated in the etchant, decomposition of the etchant proceeds rapidly.

  According to the present invention, the concentration of the halogen acid and the halogen acid salt can be reduced by performing an anodic electrolytic oxidation treatment on the etching solution having an increased halogen acid and / or halogen acid salt concentration by the method described later. It is possible to maintain good etching performance for a long time.

  There is no particular limitation on the timing of the anodic electrolytic oxidation treatment, and the anodic electrolytic oxidation treatment may be appropriately performed when accumulation of halogen acid and / or halogen acid salt occurs. In particular, when the total concentration of the halogen acid and the halogen acid salt is about 10 g / L or more, the decomposition of the etching solution proceeds rapidly, and the concentrations of manganese salt, perhalogen acid, perhalogenate and the like tend to decrease remarkably. is there. For this reason, it is preferable to perform an anodic electrolytic oxidation treatment on the etching solution in which the total concentration of the halogen acid and the halogen acid salt is about 10 g / L or more.

  In addition, when performing anodic electrolysis, there is no particular limitation on the concentration of manganese salt, inorganic acid and perhalogen acid in the etching solution to be treated, and anodic electrolysis is performed on an etching solution of any concentration. Can do. Since the concentration of the manganese salt decreases as the etching process proceeds, the manganese salt may not be included in the etching solution when the anodizing process is performed. Such an etching solution can be continuously used by adjusting the concentration of the active ingredient to a predetermined range after the anodic electrolytic treatment.

  In the treatment method of the present invention, first, when a precipitate is contained in the etching solution to be treated, it is preferable to remove the precipitate by a method such as filter filtration.

  Next, an anodic electrolytic oxidation treatment is performed on the etching solution. A schematic diagram of an example of a processing apparatus used for electrolytic treatment is shown in FIG.

  As the anode, any insoluble electrode can be used without particular limitation. Specific examples of insoluble electrodes include Ti / Pt (Ti coated with platinum coating), Ti / Ir oxide (Ti coated with Ir oxide coating), Ti / Ru (Ti Ru oxide) Coated), Ti / Ir oxide-Ru oxide (coated by mixing Ir oxide and Ru oxide on Ti), Ti / Ir oxide-Ta oxide (Ir on Ti) Oxide and Ta oxide mixed and coated), Ti / Pt / Ir oxide-Ru oxide (Ti / Pt mixed with Ir oxide and Ru oxide and coated) , Ti / Pt / Ir oxide-Ta oxide (Ti / Pt mixed with Ir oxide and Ta oxide and coated), stainless steel, aluminum, lead alloy (Pb-Sn alloy, P -Ag alloy, Pb-Sb alloy), lead oxide (lead monoxide, lead dioxide, lead trioxide, trilead tetraoxide), lead, tin oxide, carbon, diamond electrode (diamond containing nitrogen and boron is silicon And those coated on a substrate such as niobium) and ITO electrodes (indium tin oxide). Among these anodes, lead alloys (Pb—Sn alloy, Pb—Ag alloy, Pb—Sb alloy), lead oxides (lead monoxide, lead dioxide, lead trioxide, trilead tetroxide), lead, etc. Preferably, lead oxide is particularly preferable.

  There is no restriction | limiting in particular as a cathode, Both an insoluble electrode and a soluble electrode can be used. As the insoluble electrode, an electrode similar to the above-described anode can be used. As the cathode, copper, nickel, tin, iron, zinc, brass, aluminum, stainless steel, or the like can be used. In particular, as the cathode, lead alloy, lead, Pt / Ti, nickel, copper, brass, stainless steel and the like are preferable.

  The shape of the electrode is not particularly limited, and any shape such as a rod shape, a plate shape, or a mesh shape can be used.

  If necessary, one or both of the anode and the cathode may be in a state of not being brought into direct contact with the etching solution using a diaphragm. The material of the diaphragm is not particularly limited, and any material that is stable in the etching solution may be used. For example, an unglazed porcelain diaphragm can be used. There are no particular limitations on the type, shape, size, etc. of the porcelain diaphragm, as long as it is large enough to accommodate the electrodes. In the case of using a diaphragm, as the electrolytic solution in the electrode chamber, for example, an aqueous solution of an inorganic acid can be used. In this case, it is preferable to use the same inorganic acid as the inorganic acid contained in the etching solution to be processed. The concentration of the inorganic acid used as the electrolytic solution is, for example, preferably about 2 to 200 g / L, and more preferably about 20 to 100 g / L.

  The size of the electrode plate is not particularly limited, but the surface area ratio between the anode and the cathode is preferably about anode: cathode = 1: 1 to 100: 1, preferably about 1: 1 to 10: 1. More preferred.

The conditions of the anodic electrolytic oxidation treatment are not particularly limited. For example, the liquid temperature is about 20 to 70 ° C., preferably about 25 to 70 ° C., and the anodic current density is about 0.1 to 20 A / dm ² , preferably It may be about 1 to 10 A / dm ² .

  The treatment time of the anodic electrolytic oxidation treatment varies depending on the amount of the etching solution to be treated, and is not particularly limited, but until the concentration of the halogen acid and the halide salt contained in the etching solution is sufficiently reduced. Electrolytic treatment may be performed.

  The anodic electrolytic oxidation treatment can be performed with or without stirring the etching solution. In particular, the concentration of the halogen acid and the halogen acid salt can be greatly reduced by performing the anodic electrolytic oxidation treatment with stirring. The stirring method is not particularly limited, and any method such as air stirring, stirring with nitrogen gas, and liquid circulation with a pump can be employed. Further, the etching solution may be stirred by a method of swinging the electrode plate. In particular, methods such as air agitation, agitation with nitrogen gas, and liquid circulation with a pump are preferred. In addition, when the electrolytic treatment is performed using the diaphragm, the electrolytic solution in the diaphragm may be stirred.

  By performing the above-described anodic electrolytic oxidation treatment, the concentration of the halogen acid and / or the halogen acid salt contained in the etching solution is decreased, and the concentration of the perhalogen acid and / or the perhalogen acid salt is increased. In addition, the manganese salt concentration may slightly decrease. Therefore, after the anodic electrolytic oxidation treatment, the performance of the etching solution can be recovered and reused by adding manganese salt, perhalogen acid, perhalogenate, or the like as necessary.

  According to the method for treating an etching solution of the present invention, a novel etching solution containing at least one component selected from the group consisting of inorganic acids, manganese salts, and perhalogenates and perhalogenates as an active ingredient By the simple method of electrolytic oxidation, the concentration of halogen acid and / or halogen acid salt that increases in the etching solution can be reduced.

  Therefore, by adopting the electrolytic treatment method of the present invention, it is possible to maintain the etching performance for a long period of time with respect to a highly safe etching solution containing the above-described manganese salt as an active ingredient.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
The electrolytic treatment was performed under the conditions shown in Table 1 below using the electrolytic treatment apparatus having the structure shown in FIG.

  The composition of the etching solution to be processed is shown in Table 2 below. The amount of each etching solution was 1 L.

  The composition of the etching solution after electrolytic treatment under the above conditions is shown in Table 3 below.

  As is clear from the above results, the etching solution having each composition shown in Table 2 is subjected to an electrolytic treatment to reduce the concentration of the halogen acid or the halogen acid salt, thereby reducing the concentration of the perhalogen acid or the perhalogen acid salt. It can be seen that the concentration can be increased.

Example 2
The electrolytic oxidation treatment was performed under the same conditions as in Example 1 with the etching solution having the composition shown in Table 4 below as the treatment target. The composition of the etching solution after the elapse of 2 hours, 5 hours and 10 hours after the start of electrolysis is shown in Table 4 below.

  As is apparent from the above results, it can be seen that the sodium iodate concentration decreases and the sodium periodate concentration increases with the lapse of electrolysis time.

Decomposition resistance test No. 1 used in Example 1. For the etching solution of No. 10, the etching solution before and after the anodic electrolytic treatment was allowed to stand at 65 ° C. for 48 hours, and then the concentration of each component of potassium permanganate, sodium periodate and sodium iodate was measured. . In addition, about the etching liquid after anodic electrolytic oxidation treatment, the potassium permanganate was added and the decomposition resistance test was done as 0.5 g / L same as the etching liquid before anodic electrolytic oxidation treatment.

  Table 5 below shows the concentration of each component in the etching solution after standing.

  As is clear from the above results, the etching solution that was not subjected to the anodic electrolytic oxidation treatment was allowed to stand at 65 ° C. for 48 hours, and then the concentrations of potassium permanganate and sodium periodate were drastically decreased. It can be seen that the amount of sodium has increased and the decomposition of the etching solution has progressed. On the other hand, it can be seen that the etching solution subjected to the anodic electrolytic oxidation treatment does not change in concentration even after being left and has good stability.

Etching performance test A flat plate of ABS resin (trade name: Psycolac 3001M, manufactured by UMG ABS Co., Ltd.) using the etching solution before performing the decomposition resistance test by the above-described method and each etching solution after the decomposition resistance test. Electroless plating was performed in the processing steps shown in Table 6 below using (10 cm × 5 cm × 0.3 cm, surface area of about 1 dm ² ) as an object to be plated.

  After the electroless plating film was formed by the above-described method, the ratio of the electroless plating film formed on the sample surface was measured to evaluate the depositability of the electroless plating.

Next, using a copper sulfate plating bath, an electroplating treatment was performed for 120 minutes at a current density of 3 A / dm ² and a temperature of 25 ° C. to form a copper plating film. The sample thus obtained was dried at 80 ° C. for 120 minutes and left to reach room temperature, and then a 10 mm wide cut was made in the plating film, and a tensile tester (manufactured by Shimadzu Corporation, Autograph SD). −100-C), the plating film was pulled perpendicular to the resin, and the peel strength was measured.

  The above results are shown in Table 7 below.

  As is clear from the above results, the etching solution before the anodic electrolytic oxidation treatment, when left at 65 ° C. for 48 hours, greatly deteriorates the etching performance, and the electroless plating deposition properties and the plating film It can be seen that the adhesion is greatly reduced. On the other hand, it can be seen that the etching solution subjected to the anodic electrolytic oxidation treatment maintained good etching performance even after the standing test, and the stability of the etching solution was greatly improved.

Example 3
No. described in Table 2 above. Using each of the etching solutions 1, 3, 5, 7, and 9, electrolytic treatment was performed under the same conditions as those described in Table 1 above while stirring the air in the etching solution. The composition of the etching solution after the electrolytic treatment is shown in Table 8 below.

  As is clear from Table 8, the concentration of the halogen acid or the halogen acid salt could be greatly reduced by performing the anodic electrolytic oxidation treatment with air stirring. Moreover, when this result is compared with the result in the case where the electrolytic treatment is performed in an unstirred state described in Table 3, the concentration of the halogen acid or the halide salt is greatly reduced by performing the air stirring. You can see that

Schematic of an example of the electrolytic treatment apparatus for enforcing the electrolysis method of this invention.

Claims (5)

From an aqueous solution containing 20 to 1200 g / L of inorganic acid, 0.01 to 40 g / L of manganese salt, and 1 to 200 g / L of at least one component selected from the group consisting of perhalogenates and perhalogenates. An etching solution electrolytic treatment method comprising:
An anodic electrolytic oxidation treatment of an etching solution in which the concentration of a halogen acid and / or a halogen acid salt is increased by use. The method according to claim 1, wherein an etching solution having a total concentration of halogen acid and halogen acid salt of 10 g / L or more is subjected to electrolytic treatment. The method according to claim 1 or 2, wherein an insoluble electrode is used as the anode. The method according to claim 1, wherein electrolysis is performed at an anode current density of 0.1 to 20 A / dm ² . The method according to any one of claims 1 to 4, wherein the anodic electrolytic oxidation treatment is performed under stirring.

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