JPH093501A - Noble metal powder mixture and method for producing noble metal jewelry using this noble metal powder mixture - Google Patents

Abstract

(57) [Summary] [Object] To provide a noble metal powder mixture for producing a noble metal jewelry and a method for producing a noble metal jewelry using this noble metal powder mixture. [Structure] In% by weight, (1) waxes: 10 to 50%, surfactant: 0.
A noble metal powder mixture containing 3 to 5% and the rest being noble metal powder. (2) Waxes: 10 to 50%, surfactant: 0.
A noble metal powder mixture containing 3 to 5% and the rest consisting of noble metal powder is heated and melted to form a slurry, and the slurry is cast into a mold and then solidified to produce a formed body, and the formed body is a ceramic powder. And a method for producing a precious metal jewelery, which comprises immersing and burning in an investment material consisting of a homogeneous mixture of an organic binder and water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precious metal powder mixture for producing a precious metal jewelry and a method for producing a precious metal jewelry using this precious metal powder mixture.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a jewelery product using a precious metal powder, a mixture of a precious metal powder and waxes is injection-molded to produce a molded product, and the molded product is fired to produce the precious metal jewelery product. Is known (see Japanese Patent Application Laid-Open No. 4-218628).

It is also possible to produce a molded body by heating and melting a mixture of the above-mentioned precious metal powder and waxes and pouring it into a mold, and firing this molded body to produce a precious metal jewelry.

There is also known a method in which a molded body of a flexible composition is embedded in ceramic powder so as not to be deformed during firing and fired (see Japanese Patent Laid-Open No. 5-114011).

[0005]

However, when the above-mentioned conventional mixture of noble metal powder and waxes is heated and melted, the noble metal powder and the waxes are separated to form a slurry in which the noble metal powder is non-uniformly dispersed. The distribution of the noble metal powder in the molded product obtained by casting the slurry in which the non-uniform dispersion is uneven is also non-uniform.

Further, when the molded body is embedded in ceramic powder and baked, cutting or cracking occurs in the extremely thin and thin delicate shape portion of the molded body during baking, resulting in defective products and mass production is difficult. Met.

[0007]

The inventors of the present invention have conducted research to solve the above problems, and as a result, (a) prevent separation of the noble metal powder and waxes that occur during heating and melting of the mixture. Then, in order to form a slurry in which the noble metal powder is uniformly dispersed in the molten wax, it is preferable to add 0.3 to 5% by weight of the surfactant.

(B) Deformation, cracking, cutting, etc. of a molded product obtained by heat-melting a mixture of a noble metal powder and a wax containing 0.3 to 5% by weight of a surfactant and then casting and molding. The results of the study have been obtained such that, in order to perform the calcination without using the calcination, the calcination should be carried out in the state of being embedded in an investment material composed of a homogeneous mixture of ceramic powder, an organic binder and water.

The present invention was made on the basis of the results of such research, and in terms of weight%, (1) waxes:
10 to 50%, surfactant: 0.3 to 5%, noble metal powder mixture consisting of the rest of noble metal powder, (2) waxes: 10 to 50%, surfactant: 0.3 to 5 %, And the remaining noble metal powder mixture consisting of the noble metal powder is heated and melted to form a slurry, the slurry is cast into a mold and then solidified to prepare a molded body, and the molded body is made of ceramic powder and an organic binder. And a method for producing a precious metal jewelery, which comprises immersing in an investment material composed of a homogeneous mixture of water and water and firing.

The wax content of the noble metal powder mixture of the present invention is limited to 10 to 50% because the wax content is 1
If it is less than 0%, sufficient fluidity cannot be obtained even if the precious metal powder mixture is heated. On the other hand, if it exceeds 50%, the amount of the precious metal powder contained in the compact is too small, and the desired dimension is obtained. This is because precious metal jewelry cannot be obtained. Further, the reason for limiting the amount of the surfactant contained in the noble metal powder mixture of the present invention to 0.3 to 5% is that if the amount is less than 0.3%, the noble metal powder cannot be uniformly dispersed in the molten wax. This is because if the content exceeds 5%, the dispersion effect cannot be further improved and the molded body is easily deformed, which is not preferable.

The waxes contained in the noble metal powder mixture of the present invention are synthetic waxes such as paraffin wax and polyethylene wax, and natural waxes such as beeswax and carnauba wax, and their mixtures are most preferably paraffin wax. preferable.

Further, the surfactant contained in the noble metal powder mixture of the present invention is specifically sorbitan fatty acid ester, propylene glycol fatty acid ester, polyglycerin fatty acid ester, fatty acid monoglyceride, polyoxyethylene sorbitan fatty acid ester, polyoxy. Such as ethylene glycerin fatty acid ester.

The noble metal powder mixture of the present invention is prepared by heating and melting waxes, adding the noble metal powder and the surfactant, and stirring the mixture. At this time, the noble metal powder mixture is a slurry, and this slurry is cast into a compact. The mold for casting the slurry may be any mold as long as it is a precision casting mold such as a plaster mold, a lost wax mold, a rubber mold, and a metal mold.

When the obtained molded product is embedded in an investment material having the same shrinkage as that of the wax and baked, even if the molded product has an extremely thin and delicate shape, No cracking, cutting, or deformation. Therefore, the investment material used in the method for producing a precious metal jewelry using the precious metal powder of the present invention is a ceramic powder: 50 to 90%,
It is preferable to use an investment material containing a cellulose-based water-soluble binder: 0.8 to 50% and the balance of water and inevitable impurities.

The precious metal powder used in the present invention may be powder of any precious metal such as gold or gold alloy, platinum or platinum alloy, silver or silver alloy.

[0016]

EXAMPLES As precious metal powder, pure gold powder having an average particle size of 10 μm, pure platinum powder having an average particle size of 5 μm, average particle size: 1
Pure silver powder of 5 μm was prepared, paraffin wax, polyethylene wax, beeswax, and galvana wax were prepared as waxes, and sorbitan monooleate was prepared as a surfactant.

After melting the above waxes by heating at 90 ° C., the noble metal powder and the sorbitan monooleate as a surfactant are added to the melted waxes so as to have the composition shown in Table 1 and stirred. Slurry noble metal powder mixtures A to K were produced.

[0018]

[Table 1]

A noble metal powder mixture having the composition shown in Table 1 was poured into a rubber mold having a thickness: 2 mm of a flower flyer, air-cooled and solidified, and then taken out from the rubber mold to prepare a flower flyer-shaped molded body. . These molded bodies were embedded in an investment material having the composition shown in Table 2 and fired under the conditions shown in Table 2 to produce flower flyer sintered bodies, and the method for producing the jewelry of the present invention (hereinafter referred to as the method of the present invention). 1 to 7, comparative jewelery manufacturing methods (hereinafter referred to as comparative methods) 1 to 2, and conventional jewelery manufacturing methods (hereinafter referred to as conventional methods) 1 to 2.

The flower flyer sintered bodies produced by the methods 1 to 7 of the present invention, the comparative methods 1 and 2 and the conventional methods 1 and 2 were taken out from the investment material and examined for the presence of cracks on the surface of the flower flyer sintered bodies. The results are shown in Table 2.

[0021]

[Table 2]

[0022]

EFFECTS OF THE INVENTION From the results shown in Tables 1 and 2, cracks are generated in the fired flower fly bodies produced by the conventional methods 1 and 2, while the flowers obtained by the methods 1 to 7 of the present invention. It can be seen that cracks are not seen in the flyer fired body. However, when the amount of the surfactant contained in the noble metal powder mixture is too small as seen in Comparative method 1, cracks are generated in the flower flyer sintered body due to the non-uniform dispersion of the noble metal powder, while in Comparative method 2 As can be seen, when the amount of the surfactant contained in the noble metal powder mixture is too large, the molded body is easily deformed and a sintered body having a desired shape cannot be obtained.

As described above, the present invention is capable of mass-producing precious metal jewelery with a simple device such as a rubber mold, and has an excellent industrial effect.

Claims (2)

[Claims] 1. Waxes by weight: 10 to 50%,
Surfactant: A noble metal powder mixture containing 0.3 to 5% and the rest being noble metal powder. 2. Waxes by weight: 10 to 50%,
Surfactant: A noble metal powder mixture containing 0.3 to 5% and the rest consisting of noble metal powder is heated and melted to form a slurry, and the slurry is cast into a mold and then solidified to prepare a formed body, A method for producing a precious metal jewelery, which comprises immersing the molded body in an investment material made of a homogeneous mixture of ceramic powder, an organic binder and water and baking the investment.