Decorative glass articles

Abstract

The present invention provides a decorative glass article having a high refractive index and high dispersibility and having excellent brilliance and fire. This decorative glass article is characterized by containing, in mol%, 10-70% of La2O3, 10-90% of Nb2O5, 0-40% of B2O3, and 0-50% of TiO2, and by having a refractive index of 2.0 or more and an Abbe number of 50 or less.

Description

[Technical field]

[0001] The present invention relates to a decorative glass article suitable for use as an ornament such as a ring, a pendant, an earring, or a bracelet. [Background technology]

[0002] According to the Japan Glass Manufacturers Association, crystal glass is defined as "glass containing lead oxide as its main component, or potassium oxide, barium oxide, titanium oxide, etc. as its main components, with high transparency, a refractive index nd of 1.52 or more, and characterized by a beautiful glossy shine and a clear tone." These crystal glasses excel in brilliance, transparency, resonance, weightiness, and workability, and are used for decorative items (jewelry, artwork, tableware, etc.).

[0003] However, because lead-containing crystal glass is harmful to the human body and prone to scratches, crystal glass that is substantially free of lead is being developed (Patent Documents 1 and 2). In terms of high refractive index, high refractive index glass for optical glass that contains large amounts of components such as Bi2O3 is known (Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 2588468 [Patent Document 2] Patent No. 4950876 [Patent Document 3] JP 2016-13971 A Summary of the Invention [Problem to be solved by the invention]

[0005] Lead-free crystal glass has a low refractive index of about 1.57, which does not provide sufficient sparkle for use as jewelry. It also has low dispersion, so the rainbow sparkle known as "fire" tends to be weak. On the other hand, high refractive index glass used in optical glass can achieve both a high refractive index and high dispersion, but the higher the refractive index, the stronger the coloring and the weaker the fire.

[0006] In view of the above, an object of the present invention is to provide a decorative glass article which has a high refractive index, high dispersion, and excellent brilliance and fire. [Means for solving the problem]

[0007] The decorative glass article of the present invention is characterized by containing, in mole percent, La2O3 10-70%, Nb2O5 10-90%, B2O3 0-40%, and TiO2 0-50%, having a refractive index of 2.0 or more, and an Abbe number of 50 or less. The glass composition containing La2O3 and Nb2O5 as essential components in this way makes it possible to obtain a decorative glass article with a high refractive index and high dispersion, and excellent brilliance and fire. In addition, glass having this glass composition is characterized by being easily colorless and transparent.

[0008] The decorative glass article of the present invention preferably contains, by mole percent, 50% or more of La2O3+Nb2O5. This makes it easier to obtain optical properties such as a high refractive index and high dispersion. In this specification, "○+○+···" means the total amount of each component listed.

[0009] The decorative glass article of the present invention preferably contains, in mol %, 0.1 to 40% of B2O3. By containing B2O3 as an essential component, vitrification is facilitated, making it easier to obtain a large-sized decorative glass article.

[0010] The decorative glass article of the present invention preferably has a coloring degree λ5 of 395 or less. This allows visible light to easily pass through, so that the article tends to be colorless and transparent. The "coloring degree λ5" refers to the shortest wavelength (nm) at which the light transmittance is 5% in the transmittance curve at a thickness of 10 mm.

[0011] The decorative glass article of the present invention may contain, in mole percent, more than 0 to 5% of at least one selected from transition metal oxides (excluding Nb2O5 and TiO2) and rare earth oxides (excluding La2O3). In this way, a glass article having a desired color tone can be obtained depending on the component contained.

[0012] The decorative glass article of the present invention is preferably subjected to chamfering, which makes it easier for light to be reflected inside the glass article, thereby making it possible to enhance the brilliance.

[0013] The decorative glass article of the present invention is suitable as a pseudo-jewel.

[0014] The decorative article of the present invention is characterized by comprising the decorative glass article described above. Effect of the Invention

[0015] According to the present invention, it is possible to provide a decorative glass article which has a high refractive index, high dispersion, and excellent brilliance and fire. [Brief description of the drawings]

[0016] [Figure 1] 1 is a plan view of Samples No. 3 and 9 in the examples. [Diagram 2] 1 is a plan view of Samples No. 11 to 14 in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The decorative glass article of the present invention is characterized by containing, in mol%, 10-70% La2O3, 10-90% Nb2O5, 0-40% B2O3, and 0-50% TiO2, having a refractive index of 2.0 or more, and an Abbe number of 50 or less. The reasons for limiting the glass composition in this way are explained below. In the following explanation of the content of each component, "%" means "mol%" unless otherwise specified.

[0018] La2O3 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 La2O3 is 10 to 70%, preferably 15 to 60%, and particularly preferably 20 to 50%. If the content of La2O3 is too low, it becomes difficult to obtain the above effects. On the other hand, if the content of La2O3 is too high, it becomes difficult to vitrify.

[0019] Nb2O5 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 Nb2O5 is 10 to 90%, and preferably 30 to 85%, 40 to 80%, and particularly 50 to 75%. If the content of Nb2O5 is too low, it becomes difficult to obtain the above effects. On the other hand, if the content of Nb2O5 is too high, it becomes difficult to vitrify.

[0020] From the viewpoint of obtaining optical characteristics of high refractive index and high dispersion, the content of La2O3+Nb2O5 is preferably 50% or more, 70% or more, and particularly preferably 90% or more. The content of La2O3+Nb2O5 may be 100%, but when other components are contained, the content may be 99.9% or less, 99% or less, and particularly preferably 95% or less.

[0021] B2O3 is a component that forms a glass skeleton and expands the vitrification range. However, if the content of B2O3 is too high, the refractive index decreases and it becomes difficult to obtain the desired optical properties. Therefore, the content of B2O3 is preferably 0 to 40%, 0.1 to 40%, 1 to 30%, 2 to 25%, and particularly preferably 3 to 20%. In addition, because a stable glass is obtained, crystallization can be prevented even if a small amount of a coloring component is added.

[0022] 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 increasing dispersion. The TiO2 content is 0 to 50%, and is preferably 0.1 to 30%, 1 to 20%, and particularly preferably 3 to 15%. If the TiO2 content is too high, the absorption edge shifts to the long wavelength side, and the transmittance of visible light (especially visible light in the short wavelength range) tends to decrease. In addition, vitrification becomes difficult.

[0023] In order to impart a desired color tone, the decorative glass article of the present invention may contain coloring components such as transition metal oxides (excluding Nb2O5 and TiO2) and rare earth oxides (excluding La2O3). Examples of transition metal oxides include Cr2O3, Mn2O3, Fe2O3, CoO, NiO, CuO, V2O5, MoO3, RuO2, etc. Examples of rare earth oxides include CeO2, Nd2O3, Eu2O3, Tb2O3, Dy2O3, Er2O3, etc. These transition metal oxides and rare earth oxides may be contained alone or in combination of two or more. The content of these transition metal oxides and rare earth oxides (the total content when two or more are contained) is preferably more than 0 to 5%, 0.001 to 5%, 0.005 to 3%, 0.01 to 2%, and particularly 0.02 to 1%. However, depending on the components contained, the coloring may be too strong, the visible transmittance may decrease, and the desired brightness and fire may not be obtained. In such cases, the content of the above transition metal oxides and rare earth oxides may be less than 1%, 0.5% or less, or even 0.1% or less.

[0024] In addition to the above components, the decorative glass article of the present invention may contain SiO2, Al2O3, ZnO, MgO, CaO, SrO, BaO, etc., each in an amount of 10% or less, in order to broaden the range of vitrification.

[0025] The decorative glass article of the present invention actively contains components that expand the vitrification range, such as La2O3, Nb2O5, and B2O3, which suppress crystallization during glass production and make 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).

[0026] If bismuth oxide (Bi2O3) is contained, the glass article tends to be excessively colored and to have poor fire. Therefore, the content of bismuth oxide in the decorative glass article of the present invention is preferably 30% or less, 20% or less, 10% or less, particularly 1% or less in mole percent, and most preferably substantially free. It is also preferable that the decorative glass article of the present invention substantially does not contain lead oxide, which is harmful to the human body. In this specification, "substantially free" means that it is not intentionally contained in the glass composition, and does not exclude the inclusion of unavoidable impurities. Objectively, it means that the content is less than 0.1% in mole percent.

[0027] The refractive index (nd) of the decorative glass article of the present invention is 2.0 or more, preferably 2.05 or more, 2.1 or more, and particularly preferably 2.15 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 2.5 or less, 2.4 or less, and particularly preferably 2.3 or less.

[0028] The Abbe number (νd) of the decorative glass article of the present invention is preferably 50 or less, 40 or less, 30 or less, and particularly preferably 25 or less. In this way, the glass article becomes highly dispersed and fire is easily generated. Although there is no particular restriction on the lower limit of the Abbe number, if it is too small, vitrification becomes unstable, so it is preferably 10 or more, and particularly preferably 13 or more.

[0029] The coloring degree λ5 of the decorative glass article of the present invention is preferably 395 or less, 390 or less, 380 or less, and particularly preferably 370 or less. This makes it easier to obtain colorless and transparent glass because visible light can easily pass through it. It also makes it easier to increase the brilliance and fire.

[0030] The decorative glass article of the present invention is preferably made to have a higher density because the higher the density, the more profound the appearance becomes, and the more luxurious the decorative glass article (particularly the glass article for jewelry) is. Specifically, the density of the decorative glass article is preferably 3 g / cm 3 More than 4g / cm 3 Above, especially 5g / cm 3 More preferably, it is equal to or greater than this.

[0031] The decorative glass article of the present invention can be used for decorative purposes such as jewelry, art, tableware, etc. For example, it can be attached as a pseudo-gemstone to ornaments (jewelry) such as rings, pendants, earrings, bracelets, etc. The shape of the decorative glass article is not particularly limited, and examples thereof include a sphere, an ellipse, a polyhedron, etc.

[0032] The decorative glass article of the present invention is preferably subjected to chamfering such as brilliant finishing, which makes it easier for light to be reflected inside the glass article, enhancing the brilliance and making it particularly suitable as a pseudo-gemstone. EXAMPLES

[0033] The decorative 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.

[0034] Table 1 shows examples (Nos. 1 to 7) of the present invention and comparative examples (Nos. 8 to 9).

[0035] [Table 1]

[0036] First, raw materials were mixed to prepare raw material batches so as to obtain the glass compositions shown in Table 1. The obtained raw material batches were melted until homogeneous, and then rapidly cooled to obtain glass samples (decorative glass articles). The melting temperatures were 1500-2000°C for samples No. 1-7, and 1400-1500°C for samples No. 8-9. The obtained glass samples were annealed near the glass transition temperature (350-700°C), and then the density, refractive index (nd), Abbe number (νd), and coloring degree (λ5) were measured and the appearance (brilliance, fire, and color tone) were evaluated by the following methods.

[0037] The density was measured by the Archimedes method.

[0038] The refractive index (nd) and Abbe number (νd) were measured by polishing the glass sample at a right angle and using a KPR-2000 (Shimadzu Corporation). The refractive index (nd) was evaluated using the measured value for the d-line (587.6 nm) of a helium lamp. The Abbe number (νd) was calculated from the above-mentioned d-line refractive index and the values ​​of 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)}.

[0039] The coloring degree (λ5) was determined by measuring the spectral transmittance of a glass sample polished to a thickness of 10±0.1 mm, and adopting the wavelength showing a transmittance of 5% in the obtained transmittance curve. The spectral transmittance was measured using a V-670 manufactured by JASCO Corporation.

[0040] Appearance evaluation was performed as follows. First, brilliant processing was performed on each sample so that the planar shape was about 5 to 7 mmφ. Next, the processed glass samples were visually evaluated for brilliance and fire under a fluorescent light source. The evaluation was performed on a four-point scale as shown below. In addition, color tone was evaluated visually. Planar photographs of samples No. 3 and 9 are shown in Figure 1.

[0041] [Shining] ◎: Looks shiny and has a strong shine. ○: Looks shiny. △: It looks slightly shiny. ×: Almost no shine (same as a glass window).

[0042] [fire] ◎: Iridescent (various colors) sparkle can be seen. ○: Iridescent glow is visible, but the number of colors is limited. △: A slight rainbow glow is visible. ×: The rainbow color is barely visible.

[0043] As is clear from Table 1, samples No. 1 to 7, which are examples, are colorless and transparent with a λ5 of 360, have a high refractive index of 2.19 or more, and a low Abbe number of 21 or less, so that they have a strong shine and the fire can be clearly observed. On the other hand, samples No. 8 to 9, which are comparative examples, are colorless and transparent with a λ5 of 340 or less, but have a low refractive index of 1.56 or less and a high Abbe number of 45 or more, so that almost no shine is felt and the fire is difficult to observe.

[0044] An experiment was also conducted to confirm the difference in color tone when a coloring component was added. Specifically, samples No. 10 to No. 15 were prepared by adding a small amount of rare earth oxide, which is a coloring component, to the glass of sample No. 3. The results are shown in Table 2 and Figure 2 (samples No. 10 to No. 13).

[0045] [Table 2]

[0046] As shown in Table 2 and FIG. 2, glass articles can be made to have a variety of colors depending on the coloring components contained, and are therefore suitable for decorative articles (particularly jewelry).

Claims

1. In mole percent, La ２ O ３ 10-30%, Nb ２ O ５ 50-85%, B ２ O ３ Contains 0.1 to 40% TiO ２ 1. A decorative glass article comprising a pseudo-precious stone having no fluorine-containing compound, a refractive index of 2.0 or more, and an Abbe number of 50 or less.

2. In mole percent, La ２ O ３ +Nb ２ O ５ 2. The decorative glass article according to claim 1, characterized in that it contains 60% or more of glass.

3. In mole percent, Bi ２ O ３ 3. The decorative glass article according to claim 1, wherein the content of is 10% or less.

4. 4. The decorative glass article according to claim 1, wherein the Abbe number is 20 or less.

5. 5. The decorative glass article according to claim 1, wherein the refractive index is 2.19 or more.

6. Density is 5g / cm ３ The decorative glass article according to any one of claims 1 to 5, characterized in that

7. Coloring degree λ ５ 7. The decorative glass article according to claim 1, wherein the hardness is 395 or less.

8. Transition metal oxide (Nb ２ O ５ and TiO ２ ) and rare earth oxides (excluding La ２ O ３ The decorative glass article according to any one of claims 1 to 7, characterized in that it contains, in mol %, more than 0 to 5% of at least one selected from the group consisting of

9. 9. The decorative glass article according to claim 1, which is subjected to a chamfering process.

10. A decorative article comprising the decorative glass article according to any one of claims 1 to 9.

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