JP2015105382A - Clay-like molding for noble metal sintered body formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clay-like molding for noble metal sintered body formation, formed of a clay-like composition having excellent flexibility and bendability and consequently capable of increasing a period of time in molding, such as bending.SOLUTION: The clay-like molding for noble metal sintered body formation is formed by molding a clay-like composition comprising a noble metal powder and/or a noble metal alloy powder, an organic binder, an organic additive and water into a line shape having a diameter of 0.5-3.0 mm or a plate shape having a thickness of 0.2-3.0 mm. When closely wound around the outer peripheral surface of a core rod having a round cross section having a diameter of 13 mm by one round, a crack is not caused.

Description

  The present invention relates to a clay-like molded body for forming a noble metal sintered body obtained by molding a clay-like composition for forming a noble metal sintered body into a linear or plate shape.

Conventionally, for example, jewelry and art crafts made of precious metals such as rings are generally manufactured by casting or forging a precious metal-containing material such as silver or gold.
However, in recent years, precious metal clay (clay-like composition for forming a sintered body) containing precious metal powders such as silver and gold has been commercially available. There has been proposed a method for producing a precious metal jewelry or arts and crafts having the following shape (see, for example, Patent Documents 1 to 3).
According to such a method, precious metal clay can be freely modeled in the same manner as normal clay work, and after drying a modeled object obtained by modeling, it is baked using a heating furnace. It is possible to manufacture jewelry made of precious metals, arts and crafts, etc. very easily.

Japanese Patent No. 4265127 JP-A-4-26707 JP 2005-187858 A

When manufacturing this noble metal sintered body, it is necessary to first model noble metal clay, but since such modeling is mainly performed manually, the clay dries in the middle. In some cases, it may be difficult to perform processing such as bending. In particular, the shape of the precious metal sintered body is complicated due to diversification in design and preference, and the time required for the shaping tends to be long. And when the clay-like composition dries in the middle of the modeling and tries to bend the dried body, the conventional product is cracked on the surface and breaks when further bent. Therefore, when making a ring or the like, it is necessary to perform modeling in a limited time, and the design is limited.
In view of such circumstances, the present invention has been completed as a result of intensive research for the following purposes.

  The present invention has excellent flexibility and bending workability during precious metal clay modeling, and as a result, can be easily shaped such as bending, and is formed into a linear or plate shape that is convenient for modeling. It is an object of the present invention to provide a clay-like molded body for forming a precious metal sintered body.

  In the present invention, a clay-like composition containing noble metal powder and / or noble metal alloy powder, an organic binder, an organic additive and water is linear or 0.5 mm to 3.0 mm in diameter or 0.5 mm to 3.0 mm in diameter. It is a clay-like molded body for forming a precious metal sintered body formed into a 0 mm plate shape, and when it is tightly wound around the outer peripheral surface of a core rod having a circular section of 13 mm in diameter, no cracks are generated. Features.

  This type of clay-like composition is produced by stirring and mixing a noble metal powder and / or noble metal alloy powder, an organic binder, an organic additive, and water, and has excellent gas barrier properties in order to prevent curing due to drying. Stored and sold in a state of being wrapped in a packaging material such as a film. Usually, it is in a lump shape and is shaped into a desired shape after being taken out from the packaging material. At that time, before finishing the desired product such as a ring, the block-like clay-like composition is processed into a linear or elongated plate by crushing or stretching, and then processing such as rounding is performed. The clay-like composition after being taken out from is dried and hardened in a relatively short time, and when it is processed into a linear shape or a plate shape, a time may elapse, and then it may be cracked. For this reason, after taking out from a packaging material, it is necessary to model in a short time, and there exists a limit in the product shape which can be modeled.

  The clay-like molded body for forming a noble metal sintered body according to the present invention is formed into a linear or plate shape having a predetermined size, and is tightly wound around the outer peripheral surface of a core rod having a circular section of 13 mm in diameter. Since it does not crack when it is broken, it can be easily shaped such as a ring by rolling it after taking it out of the packaging material. Since it is preliminarily formed into a linear or plate shape, it can save time for processing into this molded body shape, and it becomes possible to spend a lot of time on modeling work in a shape close to the final product, It can be finished in a precise product shape to meet various demands.

  In the clay-like molded body for forming a noble metal sintered body according to the present invention, the initial hardness measured with a type E durometer is E8 to E20, and the hardness after standing for 1 hour at room temperature is E40 or less. Features.

In the conventional clay-like composition, immediately after taking out from the packaging material, it is relatively soft and easy to form, but as time passes, the hardness increases and bending for shaping becomes difficult. Become.
The clay-like molded body for forming a noble metal sintered body according to the present invention has an initial hardness of E8 to E20 immediately after taking out from the packaging material, and a hardness after aging after standing at room temperature for 1 hour is E40 or less. The increase in hardness over time is small, and therefore, there is no possibility that modeling will not be possible due to the increase in hardness during modeling, maintaining excellent flexibility and bending workability as a clay-like composition, and a ring Etc. can be easily manufactured.
Here, the initial hardness is a hardness measured within a time range of about 1 minute required for measurement with a durometer immediately after removing a packaging material containing a clay-like molded body for forming a precious metal sintered body. It shall be said. Further, the hardness after aging is the hardness measured after removing the packaging material containing the clay-like molded body for forming the precious metal sintered body and leaving it to stand at room temperature for 1 hour.

  If the hardness of Type E is within the above range, modeling is easy, and even if there is an increase in hardness during modeling, there is no problem with modeling. Moreover, if the hardness after time is in this range, sufficient flexibility is maintained even after the passage of 1 hour at room temperature, and modeling is possible thereafter. For this reason, for example, after modeling for about 30 minutes to produce a semi-finished product, it can be stored by sealing it in a packaging material, and it can be taken out from the packaging material and shaped again, temporarily interrupting the modeling operation, It can also be applied when restarting after a while.

  According to the clay-like molded body for forming a noble metal sintered body of the present invention, since it is molded into a linear or plate shape of a predetermined size, the subsequent shaping can be facilitated and a cross section having a diameter of 13 mm. Since it does not cause cracking when it is tightly wound around the outer peripheral surface of a circular core rod, the shape of a ring or the like can be easily modeled, and a precise model can be manufactured.

The clay-like molded body for forming a noble metal sintered body of the present invention has a diameter of a clay-like composition containing at least a noble metal powder such as gold powder and silver powder and / or a noble metal alloy powder, an organic binder, an organic additive and water. It is formed into a linear shape of 0.5 mm to 3.0 mm or a plate shape of thickness 0.2 mm to 3.0 mm. As the organic additive, propylene glycol can be suitably used, and glycerin and polyethylene glycol may be further included.
This clay-like molded body for forming a precious metal sintered body is stored and sold in a state of being sealed with a packaging material having gas barrier properties. After removing the packaging material, the outer periphery of a core rod having a circular cross section having a diameter of 13 mm is used. It has the characteristic that no cracks occur when it is tightly wound around the surface for one round. In addition, immediately after taking out from the packaging material (including about 1 minute time required for measurement), the hardness measured with a Type E durometer is set as the initial hardness, and after leaving the packaging material for 1 hour at room temperature The initial hardness is E8 to E20, and the post-time hardness is E40 or less.
Details will be described below.

(A) Noble metal powder, noble metal alloy powder As the noble metal powder and noble metal alloy powder used in the present invention, gold powder, silver powder, copper powder, platinum powder, and alloy powders thereof can be used. A mixed powder of silver powder and copper powder can also be used. As the silver alloy powder, a silver-copper alloy is preferably used. These noble metal powder and / or noble metal alloy powder are the main components of the clay-like composition constituting the clay-like molded body for forming a noble metal sintered body. In order to achieve the effect of the present invention, the content is not a dominant condition, but in constituting a more practical clay-like composition, the content is 50% by mass or more and 95% by mass or less. It is preferable that That is, when the content is less than 50% by mass, the texture and gloss of the noble metal are not obtained. On the other hand, when the content exceeds 95% by mass, the elongation and strength of the clay-like composition are lowered, which is not preferable.

(B) Organic Binder The organic binder used in the present invention is at least one or two of cellulose binder, polyvinyl binder, acrylic binder, wax binder, resin binder, starch, gelatin, and wheat flour. You may comprise by the combination of a seed | species or more. Of the above, it is most preferable to use a cellulose-based binder, particularly water-soluble cellulose such as methylcellulose.

(C) Organic additive Propylene glycol is used as the organic additive used in the present invention. In this case, when there are few organic additives, it becomes easy to dry and flexibility falls with progress of time, and when too much, the formability as a clay-like composition deteriorates, and it tends to be difficult to mold, 0.1 mass%-3.0 mass% are preferable.
Furthermore, by adding glycerin and / or polyethylene glycol in addition to propylene glycol, the flexibility of the clay-like composition after drying is further improved.
When adding glycerin and polyethylene glycol, it is desirable to adjust so that the total content of propylene glycol, glycerin and polyethylene glycol is 0.1 mass% to 3.0 mass%. Glycerin and polyethylene glycol are liquid substances having both hydrophilic and lipophilic properties and are known to give viscosity when incorporated in clay-like compositions. By adding to the composition, the effect that the clay-like composition is difficult to dry even if it is left for a long time and the flexibility is not easily lowered is more increased than when propylene glycol is added alone.

  Furthermore, the clay-like composition of the present invention may further contain at least one of fats and oils, olive oil, and a surfactant as necessary.

  Examples of oils and fats include organic acids (oleic acid, stearic acid, phthalic acid, palmitic acid, sepacic acid, acetylcitric acid, hydroxybenzoic acid, lauric acid, myristic acid, caproic acid, enanthic acid, butyric acid, capric acid), Organic acid ester (organic acid ester having methyl group, ethyl group, propyl group, butyl group, octyl group, hexyl group, dimethyl group, diethyl group, isopropyl group, isobutyl group), higher alcohol (octanol, nonanol, decanol), Examples include polyhydric alcohols (glycerin, arabit, sorbitan), ethers (dioctyl ether, didecyl ether), and the like.

  The surfactant is added to and mixed with the clay-like composition, thereby pulverizing a solid material generated by the reaction between the binder and water and improving the mixing property between the noble metal powder and the binder. The kind of surfactant is not specifically limited, A normal surfactant can be used. Surfactant is a generic term for substances that have water-friendly parts (hydrophilic groups) and oil-friendly parts (lipophilic groups / hydrophobic groups) in the molecule. Polyethylene glycol in the invention is also included in the surfactant. However, the term “surfactant” as used herein refers to the one excluding the polyethylene glycol added in anticipation of the action specific to the present invention, and the dispersion / aggregation action, foaming / defoaming action, wettability improvement, flexibility Examples thereof include sodium lauryl sulfate and polyoxyethylene alkyl ether added in a predetermined amount for a smoothing action, an antistatic action and the like.

When producing a clay-like molded body for forming a noble metal sintered body having such a composition, first, an organic binder, an organic additive and water, and if necessary, fats and oils, olive oil, and a surfactant are added, and a stirring vessel is added. Stir and mix in. And this mixed solution is introduce | transduced in a kneading apparatus with a noble metal powder.
For this kneading apparatus, a stainless kneading container is used, and an inner wall of which is coated with CrN is preferable. Since the CrN coating is excellent in wear resistance and lubricity, it is possible to suppress mixing of Fe.
In the kneading apparatus, the clay-like composition can be produced by kneading the noble metal powder and the mixed solution.
In addition, although fats and oils were added at the time of stirring and mixing of the mixed solution, fats and oils and the like may be added when stirring and mixing an organic binder, an organic additive, and water, and mixing a precious metal powder therein and kneading in a kneading apparatus. it can.

The clay-like composition taken out from the kneading container is divided into blocks of an appropriate size and then formed into a linear shape having a diameter of 0.2 mm to 3.0 mm or a plate shape having a thickness of 0.2 mm to 3.0 mm. It becomes a clay-like molded body for a precious metal sintered body. In this molding, first, a lump of clay-like composition is thinly extended while being crushed by a roll or the like, and processed into a sheet. In order to obtain a plate-shaped molded body, the sheet is cut into an appropriate size with a width of 1.0 mm or more. In order to obtain a linear shaped product, the sheet is cut into a strip having an appropriate width, and the strip is rolled into a line.
The linear or plate-like clay-like molded body for forming a noble metal sintered body thus formed is then stored and sold in a state of being packaged with a packaging material.
As a packaging material, a film made of a resin such as polyvinylidene chloride (PVDC) having gas barrier properties, a metal foil, or a laminate film of a metal layer and a resin layer is used. By covering the outer surface of the door closely, contact with the outside air is blocked. Moreover, it is good also as a packaging material of the form of the bag formed with these films. Furthermore, instead of a film, a container that can accommodate a clay-like molded body for forming a noble metal sintered body, such as a box or a can made of a material having gas barrier properties, may be used as a packaging material.

And, the clay-like molded body for forming a precious metal sintered body immediately after taking out from the packaging material is considered not to be cracked when tightly wound around the outer peripheral surface of a core rod having a circular section of 13 mm in diameter. The Also, the initial hardness measured by a type E durometer according to JIS K 6253 is E8 to E20, and the hardness after aging after standing at room temperature for 1 hour is less than E40 with respect to this initial hardness. Is done.
In order to produce a noble metal sintered body from this noble metal sintered body forming clay-like molded body, first, the noble metal sintered body-forming clay-like molded body is taken out of the packaging material and is deformed by, for example, rolling it, to obtain a desired shape. After forming the modeled object, the modeled object is dried by applying hot air to the modeled object. Since the molded article is cured by drying, the precious metal sintered body is manufactured by firing after shaping using a file, a cutter, a sculpture knife, or the like as necessary. When the surface is polished after firing, gloss as a noble metal comes out and can be used for decorations and the like.
Since this precious metal sintered body forming clay-like molded body is preliminarily formed into a linear or plate-like shape, the action of kneading or extending the clay-like composition manually can be omitted, and the ring can be formed. Then, it can be easily formed into a ring shape by rounding the linear or plate-like formed body. Therefore, it is possible to spend a lot of time for forming the ring and patterning the ring surface.

In the above modeling operation, since the clay-like molded body for forming the noble metal sintered body is taken out from the packaging material, no cracks are generated when it is tightly wound around the outer peripheral surface of the core rod having a circular section of 13 mm in diameter. It can be easily formed into a ring or the like. Moreover, since initial hardness is E8-E20, after taking out a clay-like molded object from a packaging material, it is easy to model this manually. In this case, it is rich in flexibility, and only the surface is in a dry state, the packaging material is difficult to adhere, and can be easily taken out from the packaging material.
In addition, after taking out from the packaging material, the hardness after aging after standing at room temperature for 1 hour is E40 or less, so that it does not become hard during modeling and cannot be modeled. If about 1 hour has passed since the clay-like molded body for forming the precious metal sintered body was taken out from the packaging material, the molding was almost completed for a ring or the like, and the hardness after that time was E40 or less. If it is the range, modeling work can be performed almost stably from the start to the end of modeling, and a modeled object having a desired shape can be easily produced. In this case, if it is a plate-shaped molded body, it can be punched out using a mold or the like, and even in that case, the molded body is not easily chipped.

In addition, since the hardness is relatively low after lapse of time, sufficient flexibility is maintained even after 1 hour has passed after the packaging material is removed, and modeling is possible thereafter. For this reason, for example, after modeling for about 30 minutes to produce a semi-finished product, it can be stored for a while in a state sealed in a packaging material, and taken out from the packaging material for modeling again.
In this way, it can be applied to the case where the modeling work is temporarily interrupted and then restarted after a certain period of time, so for example, when modeling in multiple processes, the modeling work is performed between the processes. Modeling can be resumed while being interrupted, and modeling can be performed in various ways in a modeling classroom or the like.

Methyl cellulose as an organic binder, propylene glycol, glycerin, polyethylene glycol, surfactant, olive oil and water as organic additives were stirred and mixed in a stirring vessel, and this mixed solution was introduced into a kneading apparatus together with silver powder.
In a kneading apparatus, silver powder, a binder mixed solution, and water are kneaded to produce a clay-like composition having the composition shown in Table 1, and after forming this into a sheet shape using a roll, the width is 5 mm. Two types of molded products, a strip-shaped plate material having a thickness of 2 mm and a length of 70 mm, and a wire material having a diameter of 1.5 mm were prepared, and each was prepared as a state wrapped with a film-shaped packaging material made of polyvinylidene chloride.
About this clay-like molded body for forming a precious metal sintered body, after 1 week of production, the packaging material is removed, and it is tightly wound around the circumference of a stainless steel round bar (core bar) with a diameter of 13 mm. It was confirmed whether or not cracking occurred. The case where cracks of 1 mm or more (appropriately visible) occurred was indicated as “X”, and the case where cracks of 1 mm or more did not occur was indicated as “◯”.
Further, immediately after taking out from the packaging material, the hardness was measured with a type E durometer according to JIS K 6253. It took about 1 minute from taking out the clay-like molded body for forming the precious metal sintered body from the packaging material to installing it in the durometer and starting the measurement. The hardness at this time was defined as the initial hardness.
Furthermore, the hardness after aging after leaving the clay-like molded body for forming a noble metal sintered body taken out from the packaging material in a constant temperature and humidity chamber at room temperature and 40% humidity was measured with a type E durometer.
The results are shown in Table 1.

  As is clear from Table 1, the clay-like molded body for forming a noble metal sintered body according to the example has no cracks even when tightly wound around the outer peripheral surface of a stainless steel round bar having a diameter of 13 mm. Moreover, not only the initial hardness is low, but the increase in hardness is small over time, the hardness after aging is E40 or less, and the molding can be performed even after about 1 hour from the initial state. Recognize.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.

Claims (2)

  A clay-like composition containing noble metal powder and / or noble metal alloy powder, an organic binder, an organic additive and water is a linear shape having a diameter of 0.5 mm to 3.0 mm or a plate shape having a thickness of 0.2 mm to 3.0 mm. A noble metal, which is formed into a noble metal sintered body for forming a noble metal sintered body and has no cracks when tightly wound around the outer peripheral surface of a core rod having a circular section of 13 mm in diameter. Clay-like molded body for forming a sintered body. 2. The clay for forming a precious metal sintered body according to claim 1, wherein the initial hardness measured with a type E durometer is E8 to E20, and the hardness after aging after standing at room temperature for 1 hour is E40 or less. Shaped compact.