JPH01240685A - Etching method - Google Patents

Abstract

PURPOSE:To safely regenerate an etchant at a low cost by regenerating an etchant of ferric chloride by means of air oxidation. CONSTITUTION:In the main body 1 of air oxidation equipment consisting of a device 1a for removing mist, a spray 1b, a packing material 1c, an air blower 1d, a blast pipe 1e, a pump 4, etc., an etchant of ferric chloride is sprayed at about 60 deg.C via the spray 1b. Subsequently, air is fed from the air blower 1d to oxidize the etchant, and this etchant is moved into a chemical addition tank 2, where hydrochloric acid and water are properly and automatically added through a supply pipe 2e based on the values measured by means of an oxidation-reduction electrometer 2b, a specific gravity measurement sensor 2c, an acid concentration measurement electrometer 2d, etc., and the resulting mixture is agitated. This etchant is allowed to flow via a transport tube 5 into an etching device 3 and then circulated into the spray 1b in the main body 1 of the air oxidation equipment by means of the pump 4. By this method, etching can be safely and inexpensively carried out while keeping the concentration of ferric chloride at the prescribed conditions.

Description

[Detailed description of the invention] , [Subject of the invention] The present invention relates to an etching method.

[Prior art] Methods for regenerating foamed ferric chloride etchant include adding an oxidizing agent such as hydrogen peroxide or sodium hypochlorite, contacting it with chlorine gas, and electrolysis. be.

The method of adding hydrogen peroxide has poor reaction efficiency, and in order to achieve the desired regeneration, it must be added at multiple levels; therefore, the etchant is considerably diluted, which may affect the etching equipment. It is undesirable because it affects
This method is also costly.

The method of using sodium hypochlorite is dangerous because it generates chlorine gas when added as a concentrated solution. Therefore, it must be added in a diluted state, which poses the problem of diluting the etchant like hydrogen peroxide. In addition, salt accumulates, making it inconvenient for repeated recycling. Similarly, a method using a chlorate such as sodium chlorate is also unfavorable in terms of accumulation of alkali salts.

As mentioned above, the method of oxidation regeneration using chemicals is not suitable as a method of connecting the regeneration device and the etching apparatus a and continuously reusing the etchant, which is the object of the present invention.

The method of regeneration using chlorine gas is the most efficient and ideal method in terms of chemical reactions, but chlorine gas is extremely harmful and poses problems in terms of the working environment and pollution.

In contrast, the electrolytic method does not have the above-mentioned problems, and the metal dissolved by etching can be precipitated and separated, making it an ideal method from the point of view of regeneration. The current situation is that it is not.

[Object of the Invention] An object of the present invention is to provide an etching method that eliminates the drawbacks of the prior art described above, regenerates an etchant at low cost and safely, and utilizes the same.

[Summary of the Invention] The gist of the present invention is to utilize air oxidation as a method for regenerating etchant. This ensures safety and regenerates the etchant with good quality and properties, allowing for cyclic use.

Air oxidation is efficient at about 75 to 80°C, but is limited by the desired value or the heat resistance of the circulation path piping, pumps, etc. Generally, the heat resistance temperature is limited to about 50 to 70°C for medium- to high-density polyethylene or hard vinyl chloride.

[Embodiments of the Invention] Fig. 1 shows a system diagram of the etching method of the present invention, where l is the main body of the air oxidizer, 1a is the mist removal device, lb is the spray, lc is the filler, and ld is the blower. , 1e
is a blower pipe, If is a heat insulator, 2 is a chemical addition tank body, 2a is a stirrer, 2b is an oxidation-reduction potentiometer, and 2c is a ratio sensor.

2d is an electrometer for measuring acid concentration, 2e is a chemical supply pipe, and 3 is a mechanical
4 is a pump, and 5 is a transport pipe.

In FIG. 1, the air oxidizer main body l includes a sprayer 1b.
It is composed of a filling material 1c, a blower 1d, a blower pipe 1e, a mist removing device 1a, a pump 4, and the like. Pump 4 is 5001/s at a pressure of 10Kgf/Cm"
The etchant is atomized in the form of a mist from the spray 1b. The temperature of the etchant is 60°C.

Next, air is blown at a rate of 411d or is/*tn to oxidize the etchant. The oxidized etchant is transferred to the chemical addition tank 2, and appropriate hydrochloric acid, Add water.

The inside of the chemical addition tank 2 is stirred with agitation@2a, and the etchant after adding the chemicals is flowed into the oxidation device 3 through the transport pipe 5, and then transferred to the air oxidation device main body l again by the pump 4.
of spray 1b.

Under the above conditions, the amount dissolved in the etchant was 200g/hO.
When etching an alloy of 58 iron and 421 nickel continuously at a rate of nr, the degree of aging of the etchant (the number obtained by dividing the divalent iron by the total iron in the etchant) is 0.18 to 0.
It is possible to maintain sufficient practicality within the range of 19.

In this embodiment, is the chemical addition tank 2 shown before the etching device 3? It's okay even after i3.

[Effects of the Invention] By carrying out the present invention, the concentration of ferric chloride can be controlled at a low cost and safely under certain conditions without the presence of substances such as alkali metals that impede etching. This makes it possible to establish an etching method and greatly contributes to the improvement of etching technology.

[Brief explanation of the drawing]

FIG. 1 shows a systematic diagram of the etching method of the present invention. l... Air oxidation device book 2a - Stirrer body 2b - Redox potential meter la - Mist removal device 12c - Specific gravity measurement sensor lb - Spray
2d・Acid concentration measuring electrometer LC・Filling 2e
・Chemical supply pipe ld・Air blower 41!3・・Etching device i
s・Air pipe 4・・Pump IF・Heat insulation material 5・・Transport pipe 2・・Chemical addition tank body

Claims (1)

[Claims] An etching method characterized by connecting a device for regenerating ferric chloride etchant by air oxidation and an etching device to continuously recycle the etchant.