JPH05214578A - Production of noble metal electrocasting - Google Patents

Abstract

PURPOSE:To stably, inexpensively and rapidly produce the noble metal electrocasting regardless of electrocasting conditions by executing a copper electrocasting by a copper electrocasting liquid on a wax base body, then removing the wax base body by heating and dissolving and further, executing the noble metal electrocasting thereon. CONSTITUTION:The wax base body having a low m. p. of about 60 deg.C is formed on a matrix. This wax base body is subjected to surface roughening and a catalyst, such as palladium, is imparted thereon; thereafter, the electroless copper plating is executing thereon. The wax base body formed with a conductive film in such a manner is degreased by an immersion degreasing liquid and is then subjected to copper electrocasting by using the copper electrocasting liquid. The wax base body is thereafter removed by applying heat thereto. The noble metal electrocasting is executing on the resulted copper electrocasting. As a result, the electrocasting of platinum, etc., to be executed at a high temp. of about, for example, 90 deg.C, is easily and stably executed. The copper substrate electrocasting is thereafter dissolved away by nitric acid, by which the noble metal electrocasting is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a noble metal electroformed product which is a precious metal or a noble metal alloy decorative article or a work using a wax as a matrix substrate.

[0002]

2. Description of the Related Art It is widely practiced to deposit a precious metal layer on a metal substrate by plating to make a decoration or a work. However, these methods are usually used for making an inexpensive accessory or a work. Thus, the noble metal deposition layer is thin and the strength of the entire article is maintained by the substrate itself.

On the other hand, as an alternative to this, an electroformed product for decoration is known, but when a metal such as silver or copper is used as a base material of the conventional mold, the master mold is electrolytically degreased and then activated.
After the steps of base plating and precious metal electroforming, the master mold was finally melted with nitric acid or the like to produce a precious metal electroformed product. By the way, in recent years, a wax has been favored as a base material of the master mold in view of the ease of manufacturing the master mold and the ease of melting the master mold after electroforming. Especially in the case of low melting point wax, the melting point is 60 ° C, so the master mold can be dissolved in about 15 minutes just by immersing it in warm water, and when silver or copper is used for the master mold, it takes about 3 days to melt and nitric acid etc. Compared with the large amount of chemicals required, the cost and time can be saved significantly.

However, although the wax master block has many advantages as described above, due to its characteristics, the master block melts when a process requiring a treatment at a temperature of 60 ° C. or higher comes into the process. There was a problem that electroformed products could not be made. For example, if an electrolytic degreasing agent, which is usually used at about 60 ° C, is used, the sharpness of the mother die is impaired, and when manufacturing platinum electroformed products, commercially available platinum electroforming liquid is used at a high temperature of 90 ° C. Therefore, there is a problem that the mother die melts out and an electroformed product cannot be produced.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a manufacturing method for producing an electroformed product of a noble metal by using a wax as a base material of a mold.

[0006]

In order to solve the above-mentioned problems, the present invention is to degrease a wax substrate on which a conductive coating is formed with an immersion degreasing solution, and then perform copper electroforming with a copper electroforming solution, After that, the wax base subjected to the copper electroforming is heated to extract the wax, and the noble metal electroforming is further performed. According to the above method, the wax base is used as a master mold and the noble metal electrode having a high operating temperature is used. A precious metal electroformed product can be produced while using a casting liquid.

In the above method of the present invention, before noble metal electroforming,
By using copper electroforming as the base plating, which was conventionally thin, it has sufficient strength, and the wax of the mother die can be extracted at the stage when the base copper electroforming is finished. In this way, by extracting the wax after electroforming the copper base, it is not necessary to worry about the processing temperature in the subsequent noble metal electroforming treatment, for example, even when using the platinum electroforming liquid used at 90 ℃, electroformed products It can be manufactured. Further, after electroforming the noble metal, the copper electroforming as the base is easily dissolved by dipping in nitric acid or the like, and an electroformed product containing only the noble metal is completed. As an example of the base copper electroforming liquid, a copper sulfate electroforming liquid that can be used at 30 to 40 ° C. is suitable. In the degreasing process, by changing the electrolytic degreaser used at about 60 ° C to the immersion degreaser used at 40 ° C,
The sharpness of the mother mold is no longer compromised.

[0008]

EXAMPLE An example of a method for producing an electroformed product using a wax as a mother mold according to the present invention will be described, but the present invention is not limited thereto. A base material for a pendant was prepared with a low melting point wax. This wax substrate was immersed in ultrasonically applied acetone for 24 minutes to roughen the surface, and then immersed in a mixed solution of 50 ml of trichloroethane and 150 ml of isopropyl alcohol for 6 minutes to expand the surface. Then, the wax substrate was dipped in a solution prepared by dissolving 4 g of polyvinyl alcohol in a mixed solution of 100 ml of water and 100 ml of isopropyl alcohol, treated for 6 minutes while applying ultrasonic waves, and then taken out of the substrate and left to dry at room temperature for 8 hours. .. Then, the substrate is
Re-immerse in a mixed solution of isopropyl alcohol and polyvinyl alcohol, treat for 6 minutes while applying ultrasonic waves,
The operation of taking out and drying at room temperature for 8 hours was repeated. Next, 100 ml of water, 100 ml of isopropyl alcohol, 4 hydrochloric acid
The above substrate was immersed in a solution of 2 g of polyvinyl alcohol and 0.1 g of palladium chloride dissolved in a mixed solution of ml for 6 minutes, and then the substrate was taken out and left to dry at room temperature for 8 hours. After that, it was again immersed in the mixed solution of water, isopropyl alcohol, hydrochloric acid, polyvinyl alcohol and palladium chloride for 6 minutes and dried at room temperature for 8 hours. After the hydrophilic coating was firmly applied on the wax substrate in this manner, catalyzing treatment and accelerator rating treatment were performed.
MK220 manufactured by Muromachi Chemical Co., Ltd. was used as the catalyzing solution, and palladium chloride 1 g / l, stannous chloride 70 g /
1, a solution prepared to have a concentration of 31 ml / l HCl was used, and MK330 (MK 330: 10 ml + water: 90 ml) manufactured by Muromachi Chemical Co., Ltd. was also used as the accelerator solution. The substrate coated with the hydrophilic coating is immersed in the above-mentioned catalyzing solution with a stirrer at room temperature for 10 minutes, taken out and thoroughly washed with water, then immersed in the above-mentioned accelerator solution at room temperature for 10 minutes and washed with water to impart a catalyst. I went. Next, electroless copper plating was performed on the wax substrate to which the catalyst was added. As the electroless copper plating bath, a solution prepared by using an alkaline electroless copper plating bath MK430 manufactured by Muromachi Chemical Industry Co., Ltd. to have a copper concentration of 22.9 g / l was used, and the catalyst-added wax substrate was stirred for 20 minutes while air stirring at room temperature. After immersion, it was washed with water. After that, it was made at 60 ° C at 40 ° C with Japan Electroplating Engineering's immersion degreaser Eatrex # 11.
Immersion degreasing for 2 seconds, washing with water, immersion in a 10% by volume sulfuric acid aqueous solution for 30 seconds, washing with water, and a copper electroforming solution containing an additive for copper electroforming manufactured by Ebara Cordierite at 40 ° C, 10 A / dm Electrolysis was performed at a current density of ² for 60 minutes, and copper electroforming was performed at 50 μm. afterwards,
Nippon Electroplating Engineers Gold Strike Plating Solution Aurobond plating at 32 ° C for 6V for 30 seconds, then using Nippon Electroplating Engineering Gold Plating Solution Autoronex CI at 32 ° C at 1 A / dm ² The substrate coated with 1 μm of gold by plating at a current density for 6 minutes was immersed in hot water for 15 minutes, and the wax material was extracted from the small holes previously formed on the copper electroforming. The copper electroformed product thus obtained was electroformed with a platinum electroforming bath Platinate manufactured by Nippon Electroplating Engineering Co., Ltd. at 90 ° C. and a current density of 2.5 A / dm ² for 280 minutes. , 100 μm platinum electroforming was performed. Then, it was washed with water, immersed in nitric acid for 30 minutes to dissolve the electroplated copper base, and further washed with water to form an electroplated pendant of pure platinum. This electroformed pendant beautifully reproduces the shape of the mother mold,
It was a very good product with no pinholes or lumps.

[0009]

PRIOR ART A wax substrate was subjected to electroless copper plating in the same manner as in the examples. Then, at 60 ° C with an electrolytic degreasing agent manufactured by Nippon Electroplating Engineers,
Electrolytic degreasing was performed for 60 seconds at a current density of ² A / dm ² . At this time,
The base material was softened by heat and its shape was slightly deformed. Then, it was washed with water, immersed in a 10% by volume sulfuric acid aqueous solution for 30 seconds and washed with water, and the additive for copper plating manufactured by Nippon Electroplating Engineers Co., Ltd. was added with Cubus M at room temperature for 2 A / Electrolysis was performed at a current density of dm ² for 20 minutes, and copper plating was performed at 10 μm. After that, it was washed with water, and when electroplating was carried out at 90 ° C. with a platinum electroforming solution Platinate manufactured by Japan Electroplating Engineering Company, the wax base melted and the copper plating was cracked, and it could not be electroformed at all. ..

[0010]

As described above, according to the method for producing a noble metal electroformed product of the present invention, a noble metal electroformed product having a low-melting wax as a matrix is stable regardless of the type of noble metal electroformed liquid. It becomes possible to manufacture by making it possible to save the cost and time significantly as compared with the case of using a metal such as silver or copper as the mother die.

Claims (1)

[Claims] 1. A method for manufacturing a noble metal electroformed product using a wax substrate as a master mold, after dewaxing a wax substrate subjected to a conductive film forming treatment with an immersion degreasing solution and then copper electroforming with a copper electroforming solution. Then, heat is applied to the wax base on which the copper electroforming has been performed, the wax is extracted, and the noble metal electroformed product is further produced.