Crystallised glass

Abstract

A crystallized glass contains, in mass% in terms of oxide, 40.0-70.0% of an SiO2 component, 11.0-25.0% of an Al2O3 component, 3.0-19.0% of an Na2O component, 0.5-12.0% of a TiO2 component, 0-15.0% of an Fe2O3 component, 0-4.0% of a CoO+Co3O4 component, from more than 0% to 19.0% of an Fe2O3+CoO+Co3O4 component, and a component containing at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, the content of each, when contained, being from more than 0% to 2%.

Description

Glass-ceramics

[0001] The present invention relates to glass-ceramics.

[0002] In recent years, there has been an increasing demand for glass to be used as the housing (exterior) of electronic devices such as smartphones and tablet PCs. Glass for these applications is also required to have strength and hardness sufficient to withstand harsh use. Patent Document 1, for example, discloses crystallized glass that has various physical properties required for an information recording medium substrate, as glass that can provide high strength and hardness. However, no studies have been conducted on glass suitable for housings. When glass is used as the housing of an electronic device, it may be colored according to the design, or the color tone may be adjusted for the purpose of blocking light from the internal components to prevent it from leaking to the outside.

[0003] In recent years, the importance of recycling has increased from the perspective of reducing carbon dioxide emissions, and expectations are also high for glass recycling. Glass is highly recyclable because it is relatively easy to reshape by heating and melting, and the amount of carbon dioxide emitted during the recycling process can be kept low, and it is expected to contribute to reducing carbon footprints.

[0004] On the other hand, many glass components recovered from used electronic devices and the like are integrated with metal materials, organic materials, ceramic materials, etc., and it is usually difficult to completely separate these materials from the glass and recover them (e.g., Non-Patent Document 1). For this reason, it is difficult to avoid components derived from the integrated metal materials, etc. being mixed into recycled products as impurities, making it difficult to produce recycled products equivalent to those before recovery, and therefore the glass recycling rate remains low. In particular, the change in appearance of glass before and after recycling is easily noticeable, which hinders improvement of the recycling rate. Therefore, there is a demand for glass that can maintain the excellent appearance characteristic of glass even after reuse. In addition, there is a demand for glass with excellent melting properties to facilitate subsequent recycling.

[0005] JP 2014-114200 A

[0006] Masaru Hanawa, "Special Feature: Companies Supporting the Ceramics Industry with Chemical Technology (2023) AGC Inc. - Current Status and Issues of Plate Glass Recycling", Ceramics, Ceramic Society of Japan, March 2023, Vol. 58, No. 3, pp. 149-152

[0007] An object of the present invention is to provide a glass that has a good appearance and excellent melting properties even when it contains impurity components.

[0008] As a result of extensive research, the inventors have found that crystallized glass having a specific composition maintains the excellent appearance characteristic of glass even when it contains impurity components, and also has excellent melting properties, leading to the completion of the present invention. According to the present invention, the following crystallized glass, etc. are provided. (Configuration 1) In terms of oxide, SiO ２ The composition is 40.0% to 70.0%, Al ２ O ３ Ingredients: 11.0% to 25.0%, Na ２ O component 3.0% to 19.0%, TiO ２ Composition: 0.5% to 12.0%, Fe ２ O ３ Ingredients: 0% to 15.0%, CoO + Co ３ O ４ Composition: 0% to 4.0%, Fe ２ O ３ + CoO + Co ３ O ４ A glass-ceramic containing, in mass % converted to oxide, K in an amount of more than 0% to 19.0% and at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, each of which, when present, is contained in an amount of more than 0% to 2% or less. (Configuration 2) A glass-ceramic containing, in mass % converted to oxide, K ２ The crystallized glass according to the first aspect of the present invention contains 0% to 9.0% of an O component, 1.0% to 20.0% of one or more selected from an MgO component and a ZnO component, and 0% to 3.0% of a CaO component. ２ Composition: 4.0% to 10.0%, Fe２ O ３ Component is 2.0% to 12.0%, and CoO component and Co ３ O ４ The crystallized glass according to the first or second aspect of the present invention contains, in mass % in terms of oxide, 0.05% to 0.5% of one or more components selected from the group consisting of: SiO ２ The composition is 45.0% to 65.0%, Al ２ O ３ Ingredients: 13.0% to 23.0%, Na ２ O component 8.0% to 16.0%, K ２ The glass-ceramics according to structure 1 or 2, containing 0.1% to 9.0% of an O component, 2.0% to 20.0% of one or more selected from an MgO component and a ZnO component, and 0.01% to 3.0% of a CaO component. (Structure 5) The glass-ceramics according to structure 1 or 2, having a Vickers hardness of 550 or more. (Structure 6) The glass-ceramics according to structure 1 or 2, wherein a1* is in the range of -0.10 to 0.12, b1* is in the range of -2.00 to 0.10, and L1* is in the range of 20.0 to 30.0 in the CIELAB color space coordinates determined from a reflection spectrum including specular reflection measured with a spectrophotometer under the following conditions at an observer angle of 10° using CIE illuminant D65. (Reflection spectrum measurement conditions) Sample thickness: 4 mm Light-receiving angle relative to the normal to the sample surface: 8° (Structure 7) In mass % converted to oxides, SiO ２ The composition is 40.0% to 70.0%, Al ２ O ３ Ingredients: 11.0% to 25.0%, Na ２ O component 3.0% to 19.0%, TiO ２ Composition: 0.5% to 12.0%, Fe ２ O ３ Ingredients: 0% to 15.0%, CoO + Co ３ O ４ Composition: 0% to 4.0%, Fe ２ O ３ + CoO + Co ３ O ４A method for recycling crystallized glass, comprising heating and melting crystallized glass containing a component containing more than 0% to 19.0% of a component and at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, each of which, when present, has a content of more than 0% and 2% or less, and crystallizing the glass.

[0009] According to the present invention, it is possible to provide glass that has a good appearance and excellent melting properties even when it contains impurity components.

[0010] FIG. 1 is a diagram showing XRD spectra of the crystallized glasses of Example 6, Comparative Example 1, and Comparative Example 2.

[0011] The following describes in detail the embodiments and examples of the crystallized glass of the present invention, but the present invention is not limited to the following embodiments and examples, and can be practiced with appropriate modifications within the scope of the object of the present invention.

[0012] [Ceramics] The crystallized glass according to one embodiment of the present invention contains, in mass % in terms of oxide, SiO ２ The composition is 40.0% to 70.0%, Al ２ O ３ Ingredients: 11.0% to 25.0%, Na ２ O component 3.0% to 19.0%, TiO ２ Composition: 0.5% to 12.0%, Fe ２ O ３ Ingredients: 0% to 15.0%, CoO + Co ３ O ４ Composition: 0% to 4.0% Fe ２ O ３ + CoO + Co ３ O ４and a component containing at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, the content of each of these elements, when present, being greater than 0% and not more than 2%.

[0013] The crystallized glass according to one embodiment of the present invention exhibits a good appearance with the smoothness and smooth luster of glass even when containing impurity components, and can maintain a color tone equivalent to that of glass without impurity components. It also has excellent melting properties, and a homogeneous melt is easily obtained when melted. Therefore, the crystallized glass is easy to use as a product even when recycled, and is also an excellent raw material for recycling, so it is expected to contribute to improving the recycling rate.

[0014] In this specification, the impurity component refers to a component (e.g., an oxide) containing at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, as will be described in detail later.

[0015] <Constituent Components> The constituent components of the crystallized glass of the present invention will be explained. In this specification, the content of each component is expressed in mass% converted to oxide unless otherwise specified. Here, "oxide converted" refers to the amount of oxide of each component contained in the crystallized glass, expressed in mass%, when the total mass of the oxides is 100 mass%, assuming that all the constituent components of the crystallized glass are decomposed and converted to oxides. In this specification, A% to B% means A% or more and B% or less.

[0016] SiO ２ The SiO component is an essential component for forming the glass network structure of the crystallized glass. By making the amount of SiO 40% or more, the chemical durability of the obtained glass can be improved and devitrification can be suppressed.２ By keeping the content of the component at 70% or less, it is possible to prevent excessive increase in viscosity and deterioration of melting properties. ２ The content is 40.0% to 70.0%, may be 45.0% to 65.0%, or may be 50.0% to 60.0%.

[0017] Al ２ O ３ The component is SiO ２ It is an essential component that forms a glass network structure similar to Al, and can also be a component that forms a crystalline phase by heat treatment of the raw glass before crystallization. It is a component that also contributes to stabilizing the raw glass and improving its chemical durability, and when its amount is 11.0% or more, this effect is excellent. On the other hand, Al ２ O ３ By setting the content of Al to 25% or less, it is possible to prevent deterioration of melting property and devitrification property. ２ O ３ The content of the component is 11.0% to 25.0%, may be 13.0% to 23.0%, or may be 15.0% to 21.0%.

[0018] Na ２ The O component is an essential component for improving low-temperature melting properties and moldability. ２ The more O the stronger the chemical strengthening. ２ By keeping the O content at 19% or less, it is possible to prevent deterioration of chemical durability. ２ The content of the O component is 3.0% to 19.0%, may be 5.0% to 18.0%, or may be 8.0% to 16.0%. ２ The content of the O component may be 9.0% or more, or 10.5% or more.

[0019] K ２ The O component is an optional component that contributes to improving the low-temperature melting property and formability of the glass. ２ By keeping the O content at 9.0% or less, it is possible to prevent deterioration of chemical durability. ２ The content of the O component may be in the range of 9.0% or less. ２The content of the O component may be 0.1% to 9.0%, 0.1% to 8.0%, 0.1% to 7.0%, or 0.2% to 5.0%.

[0020] Inclusion of 1.0% or more of one or more elements selected from the MgO component and the ZnO component has the effect of improving low-temperature melting properties. On the other hand, by setting the content of one or more elements selected from the MgO component and the ZnO component to 20.0% or less, deterioration of devitrification properties can be suppressed. Therefore, the content of one or more elements selected from the MgO component and the ZnO component may be 1.0% to 20.0%. "The content of one or more elements selected from the MgO component and the ZnO component" refers to the total content of the MgO component and the ZnO component. The content of one or more elements selected from the MgO component and the ZnO component may be 2.0% to 20.0%, 2.0% to 19.0%, 3.0% to 18.0%, or 5.0% to 17.5%. The phrase "containing one or more selected from the group consisting of MgO and ZnO" means containing only MgO, only ZnO, or both MgO and ZnO, but preferably containing only MgO. The MgO can also be a component that forms a crystalline phase by heat treatment of the base glass before crystallization.

[0021] The CaO component is an optional component that contributes to improving the low-temperature melting property of the glass when contained in an amount exceeding 0%. On the other hand, by setting the CaO component to 5.0% or less, deterioration of devitrification can be suppressed. Therefore, the content of the CaO component may be in the range of 5.0% or less. The content of the CaO component may be 0% to 3.0%, 0.01% to 3.0%, or 0.1% to 2.0%.

[0022] TiO ２ The TiO component plays a role in nucleation for crystal precipitation, and contributes to lowering the viscosity of the crystallized glass, improving chemical durability, and coloring the crystallized glass. ２ When the content of the component is 0.5% or more, the effect is excellent. ２ By keeping the content of the TiO component at 12.0% or less, it is possible to prevent the deterioration of devitrification.２ The content of the component is 0.5% to 12.0%, may be 3.0% to 11.5%, may be 3.5% to 11.0%, or may be 4.0% to 10.0%. ２ The content of the component may be 4.1% or more, or 4.3% or more.

[0023] Fe ２ O ３ The component is a component that can form a crystalline phase, acts as a fining agent, and is an optional component that contributes to the coloring of the crystallized glass. ２ O ３ These effects are obtained when the content of the component exceeds 0%. ２ O ３ By keeping the content of this component at 15.0% or less, it is possible to suppress the deterioration of devitrification, excessive coloring, and alloying with platinum used in glass melting equipment. ２ O ３ The content of the component is 0% to 15.0%, may be 1.5% to 14.0%, may be 2.0% to 12.0%, or may be 2.1% to 10.0%.

[0024] CoO component and Co ３ O ４ One or more components selected from (CoO + Co ３ O ４ When the content of the CoO component exceeds 0%, the component may contribute to coloring of the glass-ceramic. ３ O ４ One or more components selected from (CoO + Co ３ O ４ By controlling the content of the CoO component and Co to 4.0% or less, it is possible to suppress the deterioration of devitrification and excessive coloring. ３ O ４ One or more components selected from (CoO + Co ３ O ４ The content of "CoO component and Co ３ O ４ The content of one or more selected from the CoO component and Co ３ O ４ The total content of CoO and Co ３O ４ The content of one or more selected from the components may be 0.01% to 2.0%, 0.03% to 0.8%, or 0.05% to 0.5%.

[0025] In order to obtain a desired color of the glass-ceramic while having excellent resistance to devitrification, Fe ２ O ３ + CoO + Co ３ O ４ The content of the element is more than 0% and 19.0% or less. ２ O ３ + CoO + Co ３ O ４ The "content of the component" is Fe ２ O ３ component and CoO component and Co ３ O ４ It means the total content of the components. ２ O ３ + CoO + Co ３ O ４ The content of the component may be 0.1% to 15.0%, may be 0.5% to 10.0%, or may be 1.0% to 5.0%.

[0026] The crystallized glass usually contains the following impurity components, which are oxides of the above-mentioned impurity elements: ２ O ５ Component, Ga ２ O ３ Component, As ２ O ３ Component: GeO ２ Component, SeO ２ Component Y ２ O ３ Component: ZrO ２ component, NbO component, RuO ２ Ingredients, Rh ２ O ３ component, PdO component, CdO component, In ２ O ３ Component: Sb ２ O ３ Ingredients, TeO ２ component, HfO ２ Component, Ta ２ O ３ Component, ReO ３ Ingredients: OsO ４Component: IrO ２ component, HgO component, Tl ２ O component, Bi ２ O ３ Ingredients: PoO ３ Ingredients, Ag ２ O component, Au ２ O ３ component, PbO component, SnO ２ Ingredients: WO ３ Ingredients: MoO ３ component, CuO component, Cr ２ O ３ component, MnO component, NiO component, SO ３ component, and PtO ２ At least one component selected from the components

[0027] The content of each impurity component (e.g., oxide) is more than 0% and 2% or less in terms of oxide. When the content of each impurity component is 2% or less, precipitation of metal components in the crystallized glass, remaining unmelted metal components, and the resulting non-uniformity of the glass are suppressed, and the crystallized glass is likely to exhibit a good appearance with smoothness and a smooth luster, and is likely to maintain the same color tone and appearance as glass that does not contain the oxides of the impurity components. Furthermore, when the crystallized glass is melted, a homogeneous melt is likely to be obtained. The content of each oxide of the impurity component may be 1.8% or less, 1.6% or less, 1.4% or less, 1.2% or less, or 1.0% or less.

[0028] The total amount of impurity components in the crystallized glass is not particularly limited, but may be, for example, 15% or less, 12% or less, 10% or less, 8% or less, 6% or less, 5% or less, or 3% or less in terms of oxides.

[0029] The above-mentioned impurity components (e.g., oxides) have a common function of forming metal colloids and coloring the glass-ceramics. Furthermore, these components have low bonding strength within the glass and act to break the glass's network structure, which can significantly reduce viscosity and worsen devitrification, thereby impairing meltability. Among the impurity components, components (e.g., oxides) containing Cr, Mn, Ni, V, and Pd have a common function of coloring the glass-ceramics through absorption due to dd transitions. Among the impurity components, components (e.g., oxides) containing Cu, Ag, Pb, and Bi have a common function of coloring the glass-ceramics in the ultraviolet region through absorption due to ds, dp, and sp transitions. Among the impurity components, Ge, As, Sb, and V have the function of forming a glass network structure, but their own network-forming ability is not high, and increasing their content can worsen devitrification and impair meltability. Among the impurity components, Ga, Te, Sb, Mo, and W can form a network structure of glass when coexisting with Si, B, and P, but if their contents become too high, devitrification can worsen, thereby impairing meltability.

[0030] The crystallized glass is CeO ２ The component can be contained in an amount of 0.01% to 3.0% (preferably 0.02% to 2.0%, more preferably 0.05% to 1.0%).

[0031] The amounts of the above components can be combined as appropriate.

[0032] SiO ２ Ingredients, Al ２ O ３ Ingredients: Na ２ One or more selected from the group consisting of an O component, an MgO component, and a ZnO component, and TiO ２ Component: Fe ２ O ３ Components, as well as CoO + Co ３ O ４ The total content of the components may be 90% or more, 95% or more, 98% or more, or 98.5% or more.

[0033] The crystallized glass contains B within a range that does not impair the effects of the present invention. ２ O ３ Ingredients, P ２ O ５component, BaO component, Li ２ O component, SrO component, La ２ O ３ The content of each of these components may be 0% to 2.0%, 0% or more but less than 2.0%, or 0% to 1.0%.

[0034] The crystallized glass contains CeO as a fining agent. ２ In addition to the ingredients, F and NO ｘ However, the upper limit of the content of the fining agent is preferably 5.0%, more preferably 2.0%, and most preferably 1.0%. ｘ (x is 3, etc.) is preferably not contained since it may have an adverse effect on coloring due to its unstable oxidation-reduction.

[0035] The glass-ceramics may or may not contain other components not mentioned above, as long as the properties of the strengthened glass-ceramics of the present invention are not impaired. For example, metal components such as Gd, Yb, Lu, etc. (including oxides of these metals) may be included.

[0036] <Various Physical Properties> (Chromaticity) The crystallized glass may have a* in the range of -0.10 to 0.12, b* in the range of -2.00 to 0.10, and L* in the range of 20.0 to 30.0 in the CIELAB color space coordinates determined from the reflectance spectrum, including specular reflection, measured with a spectrophotometer under the following conditions using CIE illuminant D65 at an observer angle of 10°. When a*, b*, and L* exhibit values ​​within the above ranges, the crystallized glass exhibits a good blackness with high light-blocking properties. (Reflection Spectrum Measurement Conditions) Sample Thickness: 4 mm Light-receiving angle relative to the normal to the sample surface: 8° a*, b*, and L* are measured according to the methods described in the Examples.

[0037] a* may be -0.08 to 1.10, or may be -0.06 to 1.00. b* may be -1.50 to 0.05, or may be -1.00 to 0.00. L* may be 22.0 to 29.0, or may be 23.0 to 28.0.

[0038] (Light transmittance) The crystallized glass may have a light transmittance, including reflection loss, at a thickness of 1 mm in the wavelength range of 300 nm to 700 nm of 0.20% or less, 0.15% or less, or 0.10% or less. When the light transmittance is in the above range, the crystallized glass can exhibit high light-blocking properties.

[0039] (Vickers hardness (Hv)) The Vickers hardness of the crystallized glass may be 550 or more, 580 or more, or 600 or more. High Vickers hardness has advantages such as excellent impact resistance against external impact and scratch resistance. There is no particular limit to the upper limit of the Vickers hardness, but it is, for example, 900 or less. The Vickers hardness is measured by the method described in Examples.

[0040] (Manufacturing Method) The crystallized glass according to one embodiment of the present invention can be manufactured by the following method. That is, raw materials are uniformly mixed so that the above-mentioned components are within a predetermined content range, and then melt-molded to manufacture a base glass. Next, this base glass is crystallized to manufacture a crystallized glass. The raw material of the base glass may be, for example, a glass member recovered from used electronic devices or the like.

[0041] The raw glass is heat-treated to precipitate crystals inside the glass. The heat treatment may be a one-stage or two-stage heat treatment. In the two-stage heat treatment, a nucleation step is first performed by heat treatment at a first temperature, and after this nucleation step, a crystal growth step is performed by heat treatment at a second temperature higher than that of the nucleation step. The first temperature of the two-stage heat treatment is preferably 600°C to 750°C. The holding time at the first temperature is preferably 30 minutes to 2000 minutes, more preferably 180 minutes to 1440 minutes. The second temperature of the two-stage heat treatment is preferably 650°C to 850°C. The holding time at the second temperature is preferably 30 minutes to 600 minutes, more preferably 60 minutes to 300 minutes.

[0042] In one-stage heat treatment, the nucleation step and the crystal growth step are carried out continuously at a single temperature. Typically, the temperature is raised to a predetermined heat treatment temperature, and after reaching the heat treatment temperature, the temperature is maintained for a certain period of time, and then the temperature is lowered. When heat treatment is carried out at a single temperature, the heat treatment temperature is preferably 600°C to 800°C, more preferably 630°C to 770°C. The holding time at the heat treatment temperature is preferably 30 minutes to 500 minutes, more preferably 60 minutes to 400 minutes.

[0043] A molded body may be produced from the crystallized glass by, for example, grinding and polishing, and then processed into a thin plate. The molded body processed into a thin plate may then be formed into a shape suitable for use as a housing or the like.

[0044] (Strengthening Method) The crystallized glass may be strengthened by various strengthening methods to form a compressive stress layer on the surface.

[0045] One method for strengthening crystallized glass to form a compressive stress layer on the surface is chemical strengthening, in which an alkali component present in the surface layer of the crystallized glass is subjected to an exchange reaction with an alkali component having a larger ionic radius, thereby forming a compressive stress layer on the surface layer.

[0046] The chemical strengthening method can be carried out, for example, by the following steps: The glass-ceramics is treated with a salt containing potassium or sodium, such as potassium nitrate (KNO ３ ), sodium nitrate (NaNO ３ The steel sheet is brought into contact with or immersed in a molten salt of the metal salt, a mixed salt thereof, or a composite salt thereof. The treatment of bringing the steel sheet into contact with or immersing the steel sheet in a molten salt (chemical strengthening treatment) may be carried out in one step or two steps.

[0047] The strengthening method for the crystallized glass is not limited to chemical strengthening, and may be, for example, thermal strengthening or ion implantation.

[0048] [Uses] The crystallized glass according to one embodiment of the present invention can be suitably used as components for various devices such as portable electronic devices such as smartphones and tablet PCs, optical devices, construction components, automotive components, etc., and can be suitably used as housings for various devices such as portable electronic devices and optical devices.

[0049] The crystallized glass according to one aspect of the present invention can be recovered from equipment or the like equipped with components using the crystallized glass at the stage of use, and can be produced as a recycled product (recycled product) by being heated and melted and re-formed. The crystallized glass according to one aspect of the present invention can maintain a good appearance as glass even when it is a recycled product (recycled product), so it is suitable for use as a recycled product (recycled product). In addition, since a homogeneous melt is easily obtained during melting, it is also useful when using the crystallized glass as a raw material to regenerate (recycle) glass again. The method for recycling the crystallized glass according to one aspect of the present invention includes recovering the crystallized glass according to one aspect of the present invention from a product containing the crystallized glass (including tempered crystallized glass) according to the above-mentioned one aspect of the present invention, melting the crystallized glass by heating, and crystallizing it. The melting and crystallization methods described above for the crystallized glass according to one aspect of the present invention can be directly applied.

[0050] Examples 1 to 6, Comparative Examples 1 to 3 (1) Preparation of Raw Materials As raw materials for each component of the crystallized glass, raw materials such as oxides, hydroxides, carbonates, nitrates, fluorides, chlorides, metaphosphate compounds, etc. corresponding to each component were selected, and these raw materials were weighed out to obtain the compositions shown in Table 1 and mixed uniformly.

[0051] (2) Production of Crystallized Glass Next, the mixed raw materials were placed in a platinum crucible and melted in an electric furnace at 1400°C to 1500°C for 4 to 24 hours depending on the melting difficulty of the glass composition. The molten glass was stirred to homogenize it, and after lowering the temperature, it was poured into a mold and slowly cooled to produce a base glass. The obtained base glass was crystallized by heat treatment at the temperature and time shown in Table 1. The crystallized glass was pulverized to obtain a pulverized glass. The pulverized glass was mixed with oxides containing impurity elements shown in Table 1 (CuO, Cr ２ O ３, MnO, or NiO) was added in amounts to give the concentrations shown in Table 1, and the mixture was melted in an electric furnace at 1400°C to 1500°C for 4 to 24 hours. Then, stirring, homogenization, slow cooling, and heat treatment were carried out under the same conditions as above to produce crystallized glass. (3) Vickers hardness Hv of crystallized glass: A plurality of samples for Vickers hardness measurement were taken from the crystallized glass, and pyramidal indentations were made on the sample surface using a diamond pyramidal indenter with a facing angle of 136°. The load applied was calculated as the surface area (mm ２ ) and the average value was taken as the Vickers hardness. Measurements were carried out using a micro Vickers hardness tester HMV-G21D manufactured by Shimadzu Corporation, with a test load of 200 gf and a holding time of 10 seconds. The Vickers hardness of the crystallized glass is shown in Table 1. Note that the crystallized glass of Comparative Example 3 had a non-uniform overall appearance, with black lumpy portions scattered throughout the brown matrix, so the Vickers hardness was measured separately for both the matrix portion (brown) and the lumpy portions (black). In Table 1, the upper row shows the Vickers hardness of the matrix portion (brown), and the lower row shows the Vickers hardness of the lumpy portions (black).

[0052] (4) Chromaticity: The thickness of the crystallized glass is 4 mm, and the reflection spectrum including the regular reflection in the direction of 8° relative to the normal line of the sample surface is measured using a spectrophotometer (Konica Minolta, CM-26dG). From the obtained reflection spectrum, the chromaticity L*, a*, b* (white background) is calculated using CIE illuminant D65 at an observer angle of 10°. The chromaticity L*, a*, b* of the crystallized glass are shown in Table 1.

[0053] (5) Confirmation of Crystalline Phase The crystallized glasses of Examples 1 to 6 were analyzed by EDX and confirmed to be composed of granular crystalline phases of oxides composed of Si, Al, Ti, Mg, and Fe. ３ or its solid solution, MgAl ２ Si ２ O ８ or a solid solution thereof, SiO ２ or its solid solution, MgAl ２ O ４ or its solid solution, MgTi ２ O ４or its solid solution, Mg ２ TiO ５ or its solid solution, Mg ２ SiO ４ or a solid solution thereof, and FeAl ２ O ４ or a solid solution thereof.

[0054] (6) Meltability The obtained crystallized glass was melted at 1400°C to 1500°C for 24 hours, and the state of the melt was visually observed and evaluated according to the following criteria: A: The melt was homogeneous without devitrification, unmelted matter, or precipitates occurring during melting. B: The melt was devitrified or unmelted matter or precipitates occurred during melting, and the melt was not homogeneous.

[0055] (7) Appearance The appearance of the obtained crystallized glass was visually observed and evaluated according to the following criteria. A: Both the surface and the interior of the crystallized glass were black, with no other colors observed, and it had a smooth and glossy appearance. B: A color other than black was observed on at least one of the surface and interior of the crystallized glass, or it did not have a smooth and glossy appearance. The crystallized glass obtained in Comparative Example 1 had a black surface and a reddish-brown interior, the crystallized glass obtained in Comparative Example 2 had a black surface and an ochre interior, and the crystallized glass obtained in Comparative Example 3 had a black surface and a mixture of ochre and brown interior. These samples lacked smoothness and gloss, and did not have a good appearance as glass.

[0056] (8) XRD Measurement: XRD measurements were performed on each of the raw glasses (prepared by adding impurity components) of Example 6, Comparative Example 1, and Comparative Example 2 using the following method to obtain XRD spectra. The results are shown in Figure 1. In Figure 1, (a) shows the XRD spectrum of the raw glass of Example 6, (b) shows the XRD spectrum of the raw glass of Comparative Example 1, and (c) shows the XRD spectrum of the raw glass of Comparative Example 2. From Figure 1, it can be seen that undesired crystals precipitated in (b) Comparative Example 1 and (c) Comparative Example 2 at the raw glass stage. (7) As shown in the appearance evaluation, the glasses obtained in Comparative Examples 1 and 2 had different color shades on the surface and inside, making them difficult to describe as high-quality glass. The results of the XRD measurement supported the results of the appearance evaluation. (XRD Measurement Conditions) The XRD spectrum of the raw glass was measured using an X-ray diffraction analyzer (D8Discover, manufactured by Bruker), and glass-specific halos and crystal-specific peaks were observed from the XRD spectrum.

[0057]

[0058] From Table 1, it can be seen that the crystallized glass of the present invention having a specific composition exhibits a smooth, glossy, and excellent appearance despite containing impurity components. On the other hand, the glasses obtained in Comparative Examples 1 to 3 had an uneven overall appearance, lost smoothness and a smooth gloss, and were significantly inferior to the crystallized glass of the present invention. Furthermore, the crystallized glass obtained in Examples 1 to 6 produced a homogeneous melt when melted, which indicates that the glass is easily recycled as a raw material. On the other hand, the glasses obtained in Comparative Examples 1 to 3 produced unmelted material when melted, indicating that the glass is difficult to recycle.

[0059] Although several embodiments and / or examples of the present invention have been described in detail above, those skilled in the art will readily be able to make numerous modifications to these exemplary embodiments and / or examples without substantially departing from the novel teachings and advantages of the present invention. Accordingly, these numerous modifications are within the scope of the present invention. The contents of all documents cited in this specification and of the applications from which this application claims priority under the Paris Convention are incorporated by reference in their entirety.

Claims

1. Oxide equivalent mass %: SiO ２ The composition is 40.0% to 70.0%, Al ２ O ３ Ingredients: 11.0% to 25.0%, Na ２ O component 3.0% to 19.0%, TiO ２ Composition: 0.5% to 12.0%, Fe ２ O ３ Ingredients: 0% to 15.0%, CoO + Co ３ O ４ Composition: 0% to 4.0%, Fe ２ O ３ + CoO + Co ３ O ４ and a component containing at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, the content of each of these elements, when present, being greater than 0% and not more than 2%.

2. In terms of oxide, mass %: K ２ 2. The crystallized glass according to claim 1, comprising: 0% to 9.0% of an O component; 1.0% to 20.0% of one or more components selected from an MgO component and a ZnO component; and 0% to 3.0% of a CaO component.

3. In terms of oxide, mass % is TiO ２ Composition: 4.0% to 10.0%, Fe ２ O ３ Component is 2.0% to 12.0%, and CoO component and Co ３ O ４ 3. The crystallized glass according to claim 1, which contains 0.05% to 0.5% of one or more components selected from the following:

4. In terms of oxide, mass %: SiO ２ The composition is 45.0% to 65.0%, Al ２ O ３ Ingredients: 13.0% to 23.0%, Na ２ O component 8.0% to 16.0%, K ２ 3. The crystallized glass according to claim 1, comprising 0.1% to 9.0% of an O component, 2.0% to 20.0% of one or more selected from an MgO component and a ZnO component, and 0.01% to 3.0% of a CaO component.

5. The crystallized glass according to claim 1 or 2, having a Vickers hardness of 550 or more.

6. The crystallized glass according to claim 1 or 2, wherein a1* is in the range of -0.10 to 0.12, b1* is in the range of -2.00 to 0.10, and L1* is in the range of 20.0 to 30.0 in the CIELAB color space coordinates determined from a reflectance spectrum including specular reflection measured with a spectrophotometer under the following conditions at an observer angle of 10° using CIE illuminant D65 (reflection spectrum measurement conditions): sample thickness: 4 mm, light-receiving angle relative to the normal to the sample surface: 8° 7. In mass % of oxide equivalent, SiO ２ The composition is 40.0% to 70.0%, Al ２ O ３ Ingredients: 11.0% to 25.0%, Na ２ O component 3.0% to 19.0%, TiO ２ Composition: 0.5% to 12.0%, Fe ２ O ３ Ingredients: 0% to 15.0%, CoO + Co ３ O ４ Composition: 0% to 4.0%, Fe ２ O ３ + CoO + Co ３ O ４ A method for recycling crystallized glass, comprising heating and melting crystallized glass containing a component containing more than 0% to 19.0% of a component and at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, each of which, when present, has a content of more than 0% and 2% or less, and crystallizing the glass.

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