JP7688321B2 - Glass articles - Google Patents

Description

The present invention relates to glass articles suitable for use as ornaments such as rings, pendants, earrings, and bracelets.

Glass is known that changes color when exposed to different light sources. For example, neodymium-containing glass changes color from purple in sunlight to light blue under fluorescent lighting. In addition, techniques have been proposed for customizing the color of glass by adding various coloring elements (see, for example, Patent Documents 1 and 2).

Special Publication No. 2016-537286 Special table 2019-513679 publication

However, all of the above-mentioned glasses are low-refractive-index glasses that are mainly composed of _SiO2 , and therefore do not provide sufficient brilliance when used as decorative items. In addition, the iridescent brilliance known as "fire" tends to be weak.

In view of the above, the present invention aims to provide a glass article that has excellent brilliance and fire, and changes color when exposed to different light sources.

As a result of intensive research, the present inventors have found that the above-mentioned problems can be solved by a glass article having a composition in which a base glass containing La ₂ O ₃ as an essential component contains Ho ₂ O ₃ or Nd ₂ O ₃ .

That is, the glass article of the present invention is characterized by containing, in mole percent, more than 0 to 70% La ₂ O ₃ , more than ₀ % Nb ₂ O ₅ + Ta ₂ O ₅ + Gd ₂ O ₃ + ZrO ₂ + _{TiO 2} + Ga ₂ O ₃ + B ₂ O 3 + Al 2 O ₃ , and more than 0 to 20% Ho ₂ O ₃ + Nd ₂ O ₃ . In this specification, "x + y + ..." means the total amount of each component.

The glass article of the present invention preferably contains, in mol %, more than 0% of Nb ₂ O ₅ +Ta ₂ O ₅ +Gd ₂ O ₃ +ZrO ₂ +TiO ₂ +Ga ₂ O ₃ .

The glass article of the present invention preferably contains, in mol %, more than 0 to 80% of B ₂ O ₃ +Al ₂ O ₃ .

A glass article according to another aspect of the invention is characterized by containing, in mole percent, greater than 0 to 70% La ₂ O ₃ , greater than 0% Nb ₂ O ₅ +Ta ₂ O ₅ +Gd ₂ O ₃ +ZrO ₂ +TiO ₂ +Ga ₂ O ₃ , and greater than 0 to 20% Ho ₂ O ₃ +Nd ₂ O ₃ .

A glass article according to yet another aspect of the present invention is characterized by containing, in mole percent, La ₂ O ₃ from greater than 0 to 70%, B ₂ O ₃ +Al ₂ O ₃ from greater than 0 to 80%, and Ho ₂ O ₃ +Nd ₂ O ₃ from greater than 0 to 20%.

A glass article according to yet another aspect of the invention is characterized by containing, in mole percent, greater than 0 to 70% La ₂ O ₃ , greater than 0% Nb ₂ O ₅ + Ta _{2 O 5} + Gd _{2 O 3} + ZrO ₂ + TiO ₂ + Ga ₂ O _{3 ,} greater than 0 to 80% B ₂ O ₃ + Al 2 O 3 , and greater than 0 to 20% Ho ₂ O ₃ + Nd ₂ O ₃ .

The glass article of the present invention may contain 0 to 20% by mole of a coloring component consisting of an oxide of V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Ce, Pr, or Er. In this way, the color tone of the glass article can be arranged in a variety of ways.

The glass article of the present invention preferably has a refractive index of 1.7 or more and an Abbe number of 45 or less. By increasing the refractive index of the glass article, the difference in refractive index between the inside and outside (atmosphere) of the glass article increases, making it easier for light to be reflected inside the glass article. As a result, it becomes easier to obtain sufficient brilliance as a glass article. In addition, by decreasing the Abbe number, high dispersion is achieved, making it easier for fire to be generated.

It is preferable that the glass article of the present invention exhibits a first color tone when exposed to sunlight, and exhibits a second color tone different from the first color tone when exposed to fluorescent light. In this way, it becomes easier to exhibit different color tones indoors and outdoors, making it suitable for decorative purposes.

It is preferable that the glass article of the present invention is chamfered. This makes it easier for light to be reflected inside the glass article, enhancing its brilliance.

The glass article of the present invention is preferably for decorative purposes.

The glass article of the present invention is preferably a pseudo-gemstone.

The decorative article of the present invention is characterized by comprising the above-mentioned glass article.

The present invention provides a glass article that has excellent brilliance and fire, and changes color when exposed to different light sources.

1 is a plan view of Samples No. 23, 24, and 31 in the examples.

The glass article of the present invention is characterized by _containing , in _mole percent, _{La2O3 >} 0-70%, _Nb2O5 + _Ta2O5 + _Gd2O3 +ZrO2+ _TiO2 + _Ga2O3 + _B2O3 + _{Al2O3 >} 0%, _{and Ho2O3} + _Nd2O3 > _0-20 %. The reason _for limiting the glass composition in this way will be explained below _. In the following explanation of the content _of each component, "% _" means "mol%" unless otherwise specified.

La ₂ O ₃ is a component that forms a glass skeleton and increases the refractive index without decreasing the transmittance. It also has the effect of improving weather resistance. The content of _{La 2} O ₃ is more than 0 to 70%, preferably 5 to 68%, and particularly preferably 8 to 63%. If the content of _{La 2} O ₃ is too small, it becomes difficult to obtain the above effect. On the other hand, if the content of La ₂ O ₃ is too large, it becomes difficult to vitrify.

_Nb2O5 , _{Ta2O5, Gd2O3 , ZrO2} , _TiO2 , _Ga2O3 , _B2O3 and _Al2O3 are components that increase the refractive index, decrease _the Abbe number to achieve high dispersion, and expand the vitrification range _. The content of _{Nb2O5 + Ta2O5 + Gd2O3 + ZrO2} + _TiO2 + _Ga2O3 + _B2O3 + _Al2O3 is more than 0%, and is preferably ₅ % or more, 10 _% or _more , 20% or more _, and particularly preferably 30 _{% or} more _{. If} the content of _Nb2O5 + _Ta2O5 + _{Gd2O3 + ZrO2} + _TiO2 + _Ga2O3 + _B2O3 + _Al2O3 is too small, _it is difficult to obtain _the above effects. On _the other hand, the upper limit of the content of _Nb2O5 + _Ta2O5 + _{Gd2O3 + ZrO2 +TiO2 + Ga2O3} + _B2O3 is preferably less than 100%, 99% _or less, _and particularly _{95 %} or _{less ,} taking into consideration the contents of other components.

Each of _the components _{Nb2O5 , Ta2O5} , _{Gd2O3 , ZrO2 , TiO2} , _Ga2O3 , _{B2O3 and Al2O3} will _be described in detail below.

Nb ₂ O ₅ is a component that has a large effect of increasing the refractive index, and is a component that reduces the Abbe number and provides high dispersion. It also has the effect of widening the vitrification range. The content of _{Nb 2} O ₅ is preferably 0 to 80%, 0.5 to 75%, 1 to 73%, and particularly preferably 1.5 to 70%. If the content of Nb ₂ O ₅ is too low, it becomes difficult to obtain the above effects. On the other hand, if the content of Nb ₂ O ₅ is too high, it becomes difficult to vitrify.

Ta ₂ O ₅ is a component that has a large effect of increasing the refractive index. However, if the content of Ta ₂ O ₅ is too high, vitrification becomes difficult and the raw material cost tends to increase. Therefore, the content of Ta ₂ O ₅ is preferably 0 to 60%, 0 to 50%, 0 to 45%, and particularly preferably 0.1 to 40%.

Gd ₂ O ₃ is a component that increases the refractive index. It also has the effect of improving weather resistance. However, if the Gd ₂ O ₃ content is too high, it becomes difficult to vitrify. Therefore, the Gd ₂ O ₃ content is preferably 0 to 45%, 0.1 to 40%, 1 to 35%, 3 to 30%, and particularly preferably 5 to 20%.

_ZrO2 is a component that increases the refractive index. In addition, since it forms a glass skeleton as an intermediate oxide, it has the effect of widening the vitrification range. However, if the content of _ZrO2 is too high, vitrification becomes difficult and the melting temperature becomes too high. Therefore, the content of _ZrO2 is preferably 0 to 40%, 0.1 to 35%, 1 to 30%, 3 to 25%, and particularly 5 to 20%.

_TiO2 is a component that has a large effect of increasing the refractive index, and also has the effect of increasing chemical durability. It also has the effect of decreasing the Abbe number and making it highly dispersive. The _TiO2 content is preferably 0-90%, 0.1-88%, 5-86%, and particularly 10-83%. If the _TiO2 content is too high, the absorption edge shifts to the long wavelength side, making it easier for the transmittance of visible light (especially visible light in the short wavelength range) to decrease. In addition, it becomes difficult to vitrify.

Ga ₂ O ₃ is a component that increases the refractive index. In addition, since it forms a glass skeleton as an intermediate oxide, it has the effect of widening the vitrification range. However, if the content of Ga ₂ O ₃ is too high, vitrification becomes difficult and the raw material cost tends to increase. Therefore, the content of Ga ₂ O ₃ is preferably 0 to 50%, 0 to 30%, 0 to 20%, and particularly 0 to 10%.

B ₂ O ₃ is a component that forms a glass skeleton and expands the vitrification range. However, if the content of B ₂ O ₃ is too high, the refractive index decreases and it becomes difficult to obtain the desired optical characteristics. Therefore, the content of B ₂ O ₃ is preferably 0 to 50%, 0.1 to 40%, 3 to 38%, and particularly preferably 5 to 37%.

Al ₂ O ₃ is a component that forms a glass skeleton and expands the vitrification range. However, if the content of Al ₂ O ₃ is too high, the refractive index decreases and it becomes difficult to obtain the desired optical characteristics. Therefore, the content of Al ₂ O ₃ is preferably 0 to 80%, 1 to 75%, and particularly preferably 3 to 70%.

In order to obtain optical properties of high refractive index and high dispersion, it is preferable to adjust the content of Nb ₂ O ₅ + Ta ₂ O ₅ + Gd ₂ O ₃ + ZrO ₂ + TiO ₂ + Ga ₂ O _3. The content of _{Nb 2} O ₅ + Ta ₂ O ₅ + Gd ₂ O ₃ + ZrO ₂ + TiO ₂ + Ga 2 O ₃ is preferably 0% or more, more than 0%, 5% or more, 10% or more, 15% or more, and particularly 20% or more. However, if the content of Nb _{2 O 5} + Ta ₂ O ₅ + Gd ₂ O ₃ + ZrO ₂ + TiO ₂ + Ga ₂ O ₃ is too high, it becomes difficult to vitrify, so it is preferable to make it less than 100%, 99% or less, and particularly 95% or less.

In order to facilitate vitrification, it is preferable to adjust the content _{of B2O3} + _Al2O3 . The content _{of B2O3} + _Al2O3 is preferably 0% or more, 0.1% or more, 3% or more, and particularly preferably 5% or more. However, if the content _{of B2O3} + _Al2O3 is too _high , the refractive index decreases and it becomes difficult to obtain _the desired optical characteristics, so _it is preferably 80% or less, 75% or less, and particularly preferably 70% or less.

The glass article of the present invention actively contains components that expand the vitrification range, such _{as La2O3} , _{Nb2O5 , TiO2} , and _B2O3 , which suppresses inappropriate crystallization during glass production and makes it easy to increase _the size of the glass article (for example, a diameter of 2 mm or more, 3 mm or more, 4 mm or more, and particularly 5 mm or more).

Ho ₂ O ₃ and Nd ₂ O ₃ are components that change the color tone of the glass article when exposed to different light sources. The content of _{Ho 2} O ₃ +Nd ₂ O ₃ is preferably more than 0 to 20%, 0.1 to 15%, 0.2 to 10%, and particularly 0.3 to 5%. If the content of Ho ₂ O ₃ +Nd ₂ O ₃ is too small, it is difficult to obtain the above effect. On the other hand, if the content of Ho ₂ O ₃ +Nd ₂ O ₃ is too large, it is difficult to vitrify. The content of each of the components Ho ₂ O ₃ and Nd ₂ O ₃ is preferably 0 to 20%, more than 0 to 20%, 0.1 to 15%, 0.2 to 10%, and particularly 0.3 to 5%.

In addition to the above, the glass article of the present invention may contain the following components:

_SiO2 is a component that forms a glass skeleton and expands the vitrification range. However, if the _SiO2 content is too high, the refractive index decreases and it becomes difficult to obtain the desired optical properties. Therefore, the _SiO2 content is preferably 0 to 40%, 0 to 30%, and particularly 0.1 to 20%.

MgO, CaO, SrO, BaO, and ZnO are components that expand the vitrification range. Each of these components can be contained in a range of 10% or less. If the content of these components is too high, the refractive index decreases, making it difficult to obtain the desired optical properties.

_Y2O3 is _a component that increases the refractive index and expands the vitrification range. _Y2O3 can be contained _in a range of 20% or less. If _{the Y2O3} content is too high, vitrification becomes difficult.

The glass article can be adjusted to a desired color tone by adding a coloring component consisting of an oxide of V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Ce, Pr, or Er. These coloring components may be added alone or in combination of two or more. The content of these oxides (total amount when two or more are added) is preferably 0 to 20%, 0.001 to 10%, 0.005 to 5%, and particularly 0.01 to 1%. Depending on the component added, the coloring may be too strong, the visible transmittance may decrease, and the desired brilliance or fire may not be obtained. In such cases, the content of the above oxides may be less than 1%, 0.5% or less, or even 0.1% or less.

As another aspect of the present invention, glass articles having the following glass compositions A to C can be mentioned. The reasons for limiting the content of each component in glass compositions A to C are the same as those described above.

(Glass Composition A)
It contains, in mole percent, more than 0 to 70% La ₂ O ₃ (preferably 5 to 50%, more preferably 7 to 40%), more than 0% Nb ₂ O ₅ + Ta ₂ O ₅ + Gd ₂ O ₃ + ZrO ₂ + TiO ₂ + Ga ₂ O ₃ (preferably 10 to 99%, more preferably 30 to 95%, particularly preferably 50 to 90%), and more than 0 to 20% Ho ₂ O ₃ + Nd ₂ O ₃ (preferably 0.1 to 15%, more preferably 0.2 to 10%, and even more preferably 0.3 to 5%).

(Glass Composition B)
It contains, in mole percent, La ₂ O ₃ from more than 0 to 70% (preferably 10 to 67%, more preferably 20 to 65%), B ₂ O ₃ +Al ₂ O ₃ from more than 0 to 80% (preferably 10 to 75%, more preferably 20 to 73%, even more preferably 30 to 72%), and Ho ₂ O ₃ +Nd ₂ O ₃ from more than 0 to 20% (preferably 0.1 to 15%, more preferably 0.2 to 10%, even more preferably 0.3 to 5%).

(Glass Composition C)
It contains, in mole percent, La ₂ O ₃ from more than 0 to 70% (preferably 5 to 65%, more preferably 10 to 60%), Nb ₂ O ₅ + Ta ₂ O ₅ + Gd ₂ O ₃ + ZrO ₂ + TiO ₂ + Ga ₂ O ₃ from more than 0% (preferably 5 to 90%, more preferably 10 to 80%), B ₂ O ₃ + Al ₂ O ₃ from more than 0 to 80% (preferably 3 to 70%, more preferably 5 to 65%), and Ho ₂ O ₃ + Nd ₂ O ₃ from more than 0 to 20% (preferably 0.1 to 15%, more preferably 0.2 to 10%, even more preferably 0.3 to 5%).

The glass article of the present invention preferably has a refractive index (nd) of 1.7 or more, 1.8 or more, 1.9 or more, and particularly 2.0 or more. This increases the difference in refractive index between the inside and outside (atmosphere) of the glass article, making it easier for light to be reflected inside the glass article. As a result, it becomes easier to obtain sufficient brightness as a decorative glass article. There is no particular upper limit to the refractive index, but if it is too high, vitrification becomes unstable, so it is preferably 2.6 or less, 2.5 or less, and particularly 2.4 or less.

The Abbe number (νd) of the glass article of the present invention is preferably 45 or less, less than 45, 44 or less, and particularly 41 or less. In this way, the glass article becomes highly dispersed and fire is more likely to occur. There is no particular lower limit to the Abbe number, but if it is too small, vitrification becomes unstable, so it is preferably 10 or more, and particularly 15 or more.

The glass article of the present invention changes color when exposed to different light sources. Specifically, it exhibits a first color tone when exposed to sunlight, and exhibits a second color tone different from the first color tone when exposed to fluorescent light. Sunlight and fluorescent light are light sources to which glass articles are likely to be exposed in daily life. Therefore, if the color tone of the glass article changes when exposed to sunlight and when exposed to fluorescent light, the change in color tone can be frequently observed in daily life, making it suitable for use as decoration, such as for example, pseudo-gems.

By changing the light source during observation from sunlight to fluorescent light, the color tone changes, for example, from yellow to pink, green to purple, purple to light blue, blue to purple, and purple to green. The following reasons are thought to be the reason for this change in color tone.

Sunlight has a broad emission spectrum in the visible range, whereas fluorescent light has a sharp emission spectrum in each wavelength of R (red), G (green), and B (blue). Ho ₂ O ₃ and Nd ₂ O ₃ contained in the glass article are coloring components and have multiple absorption peaks in the visible range, especially a large sharp absorption peak near the peak position of the blue light of the fluorescent light. When a glass article containing Ho ₂ O ₃ or Nd ₂ O ₃ is exposed to sunlight, even if some wavelengths near the blue light are absorbed, the light close to the blue wavelength is not absorbed, so that the RGB balance is not easily disturbed as a whole. On the other hand, when a glass article containing Ho ₂ O ₃ or Nd ₂ O ₃ is exposed to a fluorescent light, the sharp blue light component of the fluorescent light is largely absorbed, causing the RGB color balance to be lost and the color tone to change.

Since LED light also has a relatively broad emission spectrum, a change in color tone can be observed when the glass article of the present invention is exposed to LED light and when it is exposed to fluorescent light, due to the same mechanism as described above.

The glass article of the present invention can be used for decorative purposes such as jewelry, art, and tableware. For example, it can be attached to ornaments (jewelry) such as rings, pendants, earrings, and bracelets as a pseudo-gemstone. The shape of the decorative glass article is not particularly limited, and examples include a sphere, an ellipse, and a polyhedron.

The glass article of the present invention is preferably chamfered using a method such as brilliant cut, step cut, or mixed cut. This makes it easier for light to be reflected inside the glass article, enhancing its brilliance, making it particularly suitable as a pseudo-gemstone.

The glass article of the present invention will be described in detail below using examples, but the present invention is not limited to the following examples.

Tables 1 to 4 show examples of the present invention (Nos. 1 to 33) and comparative examples (Nos. 34 to 36).

First, raw materials were mixed to prepare raw material batches to obtain the glass compositions shown in the table. The obtained raw material batches were melted until homogeneous and then rapidly cooled to obtain glass samples. The melting temperatures were 1500-2000°C for samples No. 1-33 and 1400-1500°C for samples No. 34-36. The obtained glass samples were annealed near the glass transition temperature (450-720°C), and then the refractive index (nd) and Abbe number (νd) were measured and the appearance was evaluated (color change, brilliance, fire) using the following methods.

The refractive index and Abbe number were measured using a precision refractometer (Shimadzu KPR-2000) after polishing the glass sample at a right angle. The refractive index was evaluated using the measured value for the d line (587.6 nm) of a helium lamp. The Abbe number was calculated from the refractive index of the d line and the F line (486.1 nm) and C line (656.3 nm) of a hydrogen lamp, using the formula Abbe number (νd) = {(nd-1)/(nF-nC)}.

Appearance evaluation was performed as follows. First, brilliant processing was performed on each sample so that the planar shape was approximately 5 to 7 mm in diameter. Regarding color change, the color observed near a window where sunlight entered indoors was compared with the color observed indoors under fluorescent lights where sunlight did not enter. Next, the processed glass samples were visually evaluated for brilliance and fire under a fluorescent light source. Evaluation was performed on the following four-point scale. Planar photographs of samples No. 23, 24, and 31 are shown in Figure 1.

[Brilliance]
◎: Looks shiny and has a strong shine.
○: Looks shiny.
△: Looks slightly shiny.
×: Almost no shine (similar to a glass window).

[fire]
◎: Iridescent (various colors) sparkle is visible.
○: Iridescent sparkle is visible, but the number of colors is limited.
△: A slight rainbow glow is visible.
×: The rainbow color is barely visible.

As is clear from Table 1, the color tone of the samples No. 1 to 33, which are examples, changed depending on the light source, and the brightness was rated as ◎, and the fire was rated as ○ to ◎, which was good. On the other hand, the brightness of sample No. 34, which is a comparative example, was rated as ×, and the brightness and fire of sample No. 35 were rated as ×. Furthermore, sample No. 36 was rated as × for both brightness and fire, and there was no change in color tone depending on the light source.

Claims (10)

A glass article characterized in that it contains, in mole percent, 5 to 19.9% La ₂ O ₃ , 39.8 to 90% TiO ₂ , 39.8 to less than 95% Nb ₂ O ₅ + Ta _{2 O 5} + Gd ₂ O _{3 + ZrO 2 + TiO 2 + Ga 2 O 3} + B 2 O 3 + _{Al 2} O ₃ , and more than 0 to 20% Ho ₂ O ₃ + Nd 2 O 3 , has a refractive index of 1.7 or more, and an Abbe number of 45 or less, and is for decorative use. 2. The glass article according to claim 1, comprising, in mole percent, 39.8 to less than 95% of Nb ₂ O ₅ +Ta ₂ O ₅ +Gd ₂ O ₃ +ZrO ₂ +TiO ₂ +Ga ₂ O ₃ . A glass article characterized by containing, in mole percent, 5 to 29.85% La ₂ O ₃ , 39.8 to 75% Nb ₂ O ₅ , 39.8 to less than 95% _{Nb 2} O ₅ + Ta ₂ O ₅ + Gd ₂ O ₃ + ZrO ₂ + TiO ₂ + Ga ₂ O ₃ + B ₂ O 3 + _{Al 2} O ₃ , and more than 0 to 20% Ho ₂ O ₃ + Nd 2 O ₃ , having a refractive index of 1.7 or more and an Abbe number of 45 or less, and being for decorative use. 4. The glass article according to claim 3, containing, in mole percent, 39.8 to less than 95% of Nb ₂ O ₅ +Ta ₂ O ₅ +Gd ₂ O ₃ +ZrO ₂ +TiO ₂ +Ga ₂ O ₃ . 5. The glass article according to claim 3, characterized in that it contains, in mol %, more than 0 and 14.93% of B ₂ O ₃ +Al ₂ O ₃ . 6. The glass article according to any one of claims 1 to 5, characterized in that it contains, in mole percent, 0 to 20% of a coloring component made of an oxide of V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Ce , Pr or Er. 7. The glass article according to claim 1, which exhibits a first color tone when exposed to sunlight, and exhibits a second color tone different from the first color tone when exposed to fluorescent light. The glass article according to any one of claims 1 to 7 , characterized in that it is subjected to a chamfering process. 9. The glass article according to claim 1 , which is a pseudo-gemstone. A decorative article comprising the glass article according to claim 9 .