JP6590559B2 - Titanium-manganese alloys for watch or decorative exterior parts, watch or decorative exterior parts, and watch bands - Google Patents

Description

The present invention, titanium for exterior parts of timepiece or decoration (Ti) - manganese (Mn) alloys, exterior parts of timepiece or decoration, and a watchband.

  A wristwatch case which is an exterior of a wristwatch is required to have durability against rubbing and impact and a decorative property as a decoration, and in particular, a high-grade product employs a metal exterior rather than a plastic. Furthermore, in the case of a metal sheath, since it is in direct contact with the skin for a long time, a metal that does not easily cause metal allergy to the skin is desirable.

  Compared to metals such as stainless steel, titanium is lighter and easier to wear than metals such as stainless steel, and the amount of ions eluted into sweat on the skin is low, causing metal allergies to the skin. It is known to be difficult, and is attracting attention as a skin-friendly metal exterior.

  Furthermore, titanium is also interested as a material for decorative objects such as bracelets and rings that come into contact with the skin for a long time.

  However, pure titanium used in watch cases has a problem that its surface is soft and easily scratched, and it has a disadvantage that its brightness is low and decorativeness is inferior to stainless steel, which is the mainstream of watch cases. was there.

  As a technique for improving the hardness of titanium by being easily damaged, a method using a titanium-manganese alloy in which manganese, which is a hard metal, is dissolved in titanium is considered. (For example, Patent Document 1)

Hereinafter, the titanium-manganese alloy shown in Patent Document 1 will be described.
Patent Document 1 is directed to a metal implant material that is embedded in a living body, such as an artificial joint for surgical treatment or an artificial tooth root for dental treatment.

  When metals or alloys used for implants are eluted in body fluids of living bodies, there are concerns that some elements may cause some diseases, and as a result of many studies on the relationship between the eluted elements and the types of diseases, titanium and Titanium alloy is selected.

  In Patent Document 1, a variety of titanium alloys in which manganese, silver, and the like are mixed with titanium as a base material are manufactured, and the hardness and melting point of each titanium alloy are evaluated. Imposes a condition of 1900 or less, and the mixing ratio satisfying this condition is 3-15% for manganese and 5-30% for silver.

  As described above, Patent Document 1 is an invention aimed at lowering the melting point of a titanium alloy as a living body implant material. However, how the hardness and melting point of a titanium-manganese alloy depend on the mixing ratio of manganese. It is considered that the titanium alloy is suitable for a living body implant material when the mixing ratio of manganese is 3 to 15%.

JP-A-11-106852 (page 3, table 1)

  Since the metal implant material embedded in the living body according to Patent Document 1 is not touched by human eyes at the time of mounting, there is no demand for beauty. In Patent Document 1, the surface brightness that creates the beauty of a member is obtained. No consideration has been made from this perspective.

  Therefore, a titanium-manganese alloy obtained by dissolving manganese in titanium at a blending ratio of 20% described in Patent Document 1 is good in terms of hardness, but a watch or a decorative object that requires brightness as a decorative property in addition to hardness. This has the disadvantage that it is insufficient for use as an exterior part.

That is, the exterior part of the timepiece or the decorative object according to the present invention has a surface in contact with the skin, which is evaluated for fastness against rubbing and impact, and a surface which is evaluated as a decorative object.
For this reason, the exterior parts of watches or decorations are rubbed with clothes, hit with objects, sometimes fall and collide with the floor, etc., and scratches and surface shape deformation occur due to external forces. Hardness not required is required.

  In addition, since the exterior parts of watches or ornaments are always exposed to the eyes, beauty, that is, glittering of the surface, brightness is required, and metallic materials that give a dull impression are avoided, such as stainless steel There is a need for metals that exhibit bright surface properties.

  An object of the present invention is to solve the above problems. In other words, during use while worn on the human body, it has hardness that prevents abrasions and surface deformation caused by contact with clothes and objects, decorativeness with a bright texture that does not make the surface feel dull, and skin It is an object to provide an exterior part of a watch or an ornament having an affinity that does not cause metal allergy.

To solve the above problems, a titanium for exterior parts of timepiece or decoration of the present invention - manganese alloy is a binary alloy of titanium and manganese, the mixing ratio of manganese is 90 wt% to 25 wt% The brightness in CIELab (L * a * b * color system) is higher than the brightness of 100% manganese.

With the above configuration, it is possible to provide a titanium-manganese alloy with a bright texture that does not cause metal allergy to the skin and does not give a dull feeling on the surface.

  Furthermore, the Vickers hardness of the alloy of titanium and manganese is preferably 400 or more.

In this way, it becomes a titanium-manganese alloy that is less likely to be scratched or deformed while maintaining a bright texture.
Furthermore, the exterior part of the timepiece or the decorative object may be formed of the above-described titanium-manganese alloy.

  According to the present invention, a watch or decoration that prevents a scratch or surface shape deformation caused by contact with clothing or an object during wearing, has a bright texture that does not make the surface feel dull, and does not cause metal allergy to the skin. The exterior part of a thing can be obtained.

It is the graph and table | surface which show the relationship between the brightness of the titanium-manganese alloy in embodiment of this invention, and a manganese compounding ratio. It is the graph and table | surface which show the relationship between the Vickers hardness of the titanium-manganese alloy in embodiment of this invention, and a manganese compounding ratio. It is a perspective view which shows the top of the wristwatch band as an exterior part of the timepiece in the embodiment of the present invention, and a part of the wristwatch band. It is a schematic diagram which shows the structure of the vacuum arc melting apparatus used by this invention.

Hereinafter, specific embodiments of the exterior part of the timepiece or the ornament of the present invention will be described in detail with reference to the drawings.
In the description, a wristwatch band will be described as an example.

(Description of manufacturing procedure of titanium-manganese alloy)
The production procedure of the titanium-manganese alloy of the present invention will be described with reference to FIG. First, in order to clarify the manganese compounding ratio and the characteristics of the titanium-manganese alloy in the titanium-manganese alloy of the present invention, a titanium-manganese alloy in which the manganese compounding ratio with respect to titanium is changed from 0% by weight to 100% by weight. It was produced using a vacuum arc melting method.

  Five test pieces were prepared for each sample ratio. In each test piece, titanium and manganese were weighed so that the total weight of titanium and manganese was 10 g. For example, when the compounding ratio of manganese is 30% by weight, 7 g of titanium and 3 g of manganese are used.

  FIG. 4 is a schematic configuration diagram of the vacuum arc melting furnace 40. The main components are the vacuum chamber 41, the copper hearth 43 on which the arc discharge electrode 42 and the titanium-manganese alloy material are placed, and the arc discharge disposed outside the vacuum chamber 41. A power supply 45 for the gas, a gas introduction pipe 48 connected to the gas introduction port of the vacuum chamber 41, and an exhaust pipe 50 connected to the exhaust port of the vacuum chamber 41.

  A titanium-manganese alloy was produced by the following procedure. First, a mixture 44 of titanium and manganese weighed so as to have an overall weight of 10 g was put into a water-cooled copper hearth 43. Titanium used sponge titanium named after its porous shape, and manganese used granular manganese.

  The air in the vacuum chamber 41 is exhausted using a vacuum pump (not shown) connected via an exhaust pipe 50 and an exhaust valve 51 connected to the exhaust port of the vacuum chamber 41. After reducing the pressure to 10 kPa, the exhaust valve 51 is closed to stop the exhaust, and the gas introduction valve 49 attached to the gas introduction pipe 48 connected to the gas introduction port of the vacuum chamber 41 is opened to introduce the gas. Argon gas was introduced into the vacuum chamber 41 from an argon gas cylinder (not shown) connected to the valve 49 for use. The pressure of argon gas in the vacuum chamber 41 was set to 35 kPa by adjusting the amount of argon gas introduced.

  After the introduction of the gas into the vacuum chamber 41 by the above procedure, between the arc discharge electrode 42 connected by the wiring 46 from the arc discharge power supply 45 and the water-cooled copper hearth 43 connected to the wiring 47. A voltage was applied to generate arc discharge. The arc discharge acts as a so-called negative resistance and the current runs away, but the power source 45 controls the current to be constant by a current control circuit to prevent the current runaway.

The arc discharge current flows through the raw material of the titanium-manganese alloy placed on the copper hearth 43, and the raw material of the alloy melts at a high temperature. Stop arc discharge when the whole raw material melts. When the alloy cools, the top and bottom of the alloy are turned over, and arc discharge is generated again to melt the alloy material and melt the whole. Upside down and dissolution were repeated three times to uniformly dissolve the raw materials of titanium and manganese.

(Evaluation to know the characteristics of titanium-manganese alloy produced by the above method)
Next, evaluation was performed in order to know the characteristics of the titanium-manganese alloy produced by the above method. First, a method for measuring the brightness of the produced titanium-manganese alloy will be described.

  In general, RGB, CMYK, and CIELab (L * a * b * color system) are known as methods for expressing brightness and color. CIE is an abbreviation for the International Lighting Commission. CIELab (L * a * b * color system) is designed to approximate human vision. On the other hand, RGB and CMYK are given priority to the convenience of output devices such as displays and printers.

Since the exterior part of the timepiece or the ornament of the present invention appeals to human vision, CIELab (L * a * b * color system) that approximates human vision is suitable as an evaluation system. In CIELab (L * a * b * color system), the lightness is expressed by L * and the hue is expressed by a * and b *. L * = 0 is black, L * = 100 is white, and a large value of L * means that the object looks bright.
Therefore, in the present invention, the brightness of the titanium-manganese alloy was evaluated by the brightness (L *) by CIELab (L * a * b * color system).

  The brightness (L *) by CIELab (L * a * b * color system) was determined by the following method. First, the spectral spectrum of the reflected light from the test piece was measured using a spectrocolorimeter. Next, based on spectral spectrum data obtained by measurement, CIE uses color matching functions x (λ), y (λ), and z (λ) defined as the spectral sensitivity of the standard observer's eyes. Integral calculation was performed to calculate three values of tristimulus values X, Y, and Z, and brightness (L *) was obtained based on these three numerical values.

  Note that the color matching function depends on the viewing angle (the size of the object), and the CIE defines the color matching function for the 2 ° visual field and the color matching function for the 10 ° visual field. In the present invention, a color matching function having a 10-degree field of view suitable for watching a watch or an ornament is employed.

(Measurement of lightness dependence of manganese content)
The relationship between the lightness (L *) and the manganese compounding ratio in CIELab (L * a * b * color system) based on the measurement experiment results will be described with reference to FIGS. 1 (a) and 1 (b).
FIG. 1 (b) is a table showing the blending ratios of titanium-manganese alloys prepared by changing the blending ratio of manganese from 0 wt% to 100 wt% and the respective lightness (L *) in the titanium-manganese alloy. is there. The numerical values shown in the table of FIG. 1 (b) are the average values of lightness (L *) obtained by measuring with the above measuring method for five alloy specimens prepared for each manganese mixing ratio. ing.

  The graph of Fig.1 (a) is the graph plotted from the table | surface of FIG.1 (b) using the numerical value of the manganese compounding ratio, and the numerical value of the average value of lightness (L *). The horizontal axis of the graph is the manganese blend ratio (% by weight), and the vertical axis is the lightness (L *). The characteristic curve L1 shows the lightness with respect to each manganese compounding ratio.

  Looking at the characteristic curve L1, the lightness (L *) increases as the manganese blending ratio increases, the manganese blending ratio is saturated at 50% by weight, and the lightness (L *) = 82. The lightness (L *) = 82 is constant when the manganese compounding ratio is between 50 wt% and 90 wt%. The lightness (L *) = 82 is a brightness comparable to that of stainless steel.

In the present invention, in order to know the lightness necessary for the beauty required for the watch case, the test was conducted with the beauty of the appearance, that is, the sensual viewpoint. Specifically, the five selected sensory test personnel were allowed to visually observe the titanium-manganese alloy produced without disclosing the manganese compounding ratio. I was allowed to judge.

  As a result of this test, the acceptable product of the appearance quality is a titanium-manganese alloy having a manganese compounding ratio of 25% to 90% by weight, and the acceptable product is indicated by ○ in the table of FIG. Indicated by ×. That is, the result was that a titanium-manganese alloy having a manganese blending ratio of 25 wt% to 90 wt% with a lightness (L *) of 80 or more was excellent in appearance quality.

  When the acceptable product and the rejected product are distinguished on the characteristic curve L1 in FIG. 1A, the acceptable product is a solid line portion of the characteristic curve L1, and the rejected product is a dotted line portion of the characteristic curve L1. The lightness (L *) of 100% manganese is 79, which is indicated by a dotted line in FIG. 1 (a) as a reference line L2, but the acceptable product is higher than the lightness of 100% manganese indicated by the reference line L2. It can be seen that it has lightness.

(Measurement of hardness of each manganese compounding ratio)
Next, the relationship between the Vickers hardness and the manganese compounding ratio based on the measurement experiment results will be described with reference to FIGS. 2 (a) and 2 (b).

  The watch case rubs on the clothes during wearing, touches nearby objects, falls to the floor when removed, and external force is applied to the surface of the watch case. Deformation may reduce the brightness and brightness of the surface and impair the beauty. In order to prevent these problems, it is effective that the titanium-manganese alloy is hard.

  In the present invention, Vickers hardness (Hv), which is widely used, is adopted as a hardness index as a method for evaluating hardness. The Vickers hardness (Hv) is the area of the dent remaining after removing the load by applying a load to an indenter made of diamond with a regular quadrangular pyramid shape and pushing it onto the surface of the titanium-manganese alloy specimen. It is expressed as a numerical value obtained by dividing the load (expressed in kgf units or N units) by square mm units). The harder the material, the smaller the area of the dent. Therefore, the harder the material, the higher the Vickers hardness (Hv).

  FIGS. 2A and 2B are a graph and a table showing the relationship between a titanium-manganese alloy produced by changing the manganese blending ratio from 10 wt% to 90 wt% and Vickers hardness (Hv). . FIG. 2 (b) shows the average value of Vickers hardness (Hv) obtained by measuring with the above-described measuring method for five titanium-manganese alloys prepared at each compounding ratio.

  FIG. 2 (a) is a graph plotted from the table of FIG. 2 (b) using the value of the manganese blending ratio and the value of the average value of Vickers hardness (Hv). The horizontal axis of the graph of FIG. 2A is the manganese blending ratio (% by weight), the vertical axis is the Vickers hardness (Hv), and the characteristic curve H1 represents the hardness with respect to the manganese blending ratio.

  Looking at the characteristic curve H1, the Vickers hardness (Hv) increases almost linearly as the manganese compounding ratio increases.

  In the present invention, in order to know the hardness required for a watch case, an experiment was performed in which the surface of a titanium-manganese alloy test piece was rubbed with a cloth. A cotton cloth having a bristles of 2 mm was wound around a cylinder having a diameter of 10 cm, and the surface of the test piece was rubbed with a cotton cloth in such a manner that the cylinder was rotated 5 times per second with the bristles pushed into the 0.5 mm test piece. . After rubbing continuously for 1 hour, the test piece was taken out, and it was judged whether or not it was felt that the beauty of the surface of the test piece was damaged.

Scratch resistance was evaluated by the above test, and in FIG. 2 (b), the acceptable product that was judged not to lose its beauty was indicated by ○, and the unacceptable product was indicated by ×. That is, the result was that a titanium-manganese alloy having a manganese blending ratio of 25% by weight or more with a Vickers hardness of 400 or more was excellent in scratch resistance.

  In the characteristic curve H1 of the graph of FIG. 2A, the solid line portion is a pass product and the dotted line portion is a reject product. The dotted line H2 is a reference line indicating a Vickers hardness of 400.

  From the above results, it was found that a titanium-manganese alloy having a manganese blending ratio of 25 wt% to 90 wt% having lightness with excellent appearance quality is also excellent in scratch resistance.

FIG. 3 is a perspective view of a wristband showing an embodiment of the present invention, FIG. 3A shows a top 30 of the wristband, and FIG. 3B ties a wristwatch body and a buckle of the wristwatch. It is a perspective view of a part 31 of the wristwatch band.
Based on the above experimental results, the wristwatch band shown in FIG. 3 is made of a titanium-manganese alloy having a bright surface like stainless steel and a hardness that prevents scratching even when rubbed on clothes and having a manganese compounding ratio of 50% by weight. It was manufactured and forged from the alloy, and the connecting plate 32 for connecting the watch band top 30 was also in contact with the skin, so it was manufactured using the same material.

  Since the produced wristwatch band is a titanium alloy having high affinity to a living body, even if it is worn on the arm for a long time, metal allergy does not occur on the skin. Moreover, since the brightness is 82 and a value comparable to stainless steel, it is not a dull gray of titanium but a bright texture. Furthermore, since the Vickers hardness is as high as 750, the outer surface of the wristwatch band is rubbed with clothing, and even if it hits an object, there is little generation of scratches or deformation, and the deterioration of the decorativeness of the wristwatch band can be prevented.

  The watch or decorative exterior part of the present invention has no metal allergy to the skin, prevents abrasion and contact with the clothes and objects during wearing, and prevents the surface from deforming and feels dull on the surface. Since it has a bright texture that does not occur, it can be applied to all watches or decorative exterior parts to be worn on the human body.

30 Watch Band Top 31 Part of Watch Band 32 Connecting Plate 40 Vacuum Arc Melting Furnace 41 Vacuum Tank 42 Arc Discharge Electrode 43 Copper Hearth 44 Titanium-Manganese Alloy 45 Arc Discharge Power Supply

Claims (5)

A binary alloy of titanium and manganese,
The compounding ratio of manganese is 25% to 90% by weight,
A titanium-manganese alloy for watch or decorative exterior parts , characterized in that the brightness in CIELab (L * a * b * color system) is higher than the brightness of 100% manganese. The titanium-manganese alloy for an exterior part of a timepiece or an ornament according to claim 1, wherein the Vickers hardness is 400 or more. 3. The titanium-manganese alloy for watch or decorative exterior parts according to claim 1 or 2, wherein the compounding ratio of manganese is 50 to 90% by weight.   A timepiece or an exterior part of an ornament, which is formed of the titanium-manganese alloy according to any one of claims 1 to 3. A plurality of pieces of a watch band formed of the titanium-manganese alloy according to any one of claims 1 to 3,
A connecting plate that is formed of the titanium-manganese alloy according to any one of claims 1 to 3 and connects the tops;
A wristwatch band comprising:

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