Crystallized glass

Abstract

A crystallized glass comprising, in mol% based on oxides, 30.0-70.0% of a SiO2 component, 2.0-20.0% of a Al2O3 component, 2.0-20.0% of a Na2O component, 0-8.0% of a K2O component, 5.0-30.0% of one or more selected from a MgO component and a ZnO component, 0-5.0% of a CaO component, 1.0-10.0% of a TiO2 component, 0.1-5.0% of a Fe2O3 component, and 0-1.0% of one or more selected from a CoO component and a Co3O4 component, wherein when the content of the Fe2O3 component is defined as A1% and the content of the TiO2 component is defined as A2%, A1×A2 is 1.0 or more.

Description

Glass-ceramics

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

[0002] In recent years, there has been an increasing demand for glass as the housing (exterior) of electronic devices such as smartphones and tablet PCs. Glass for these applications is also required to have sufficient strength 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 a glass that can achieve high strength. 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 color tone of glass before and after recycling is easily noticeable, which hinders an improvement in the recycling rate, and therefore there is a demand for glass that changes little in color tone even when reused.

[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 exhibits little color change even when it contains impurity components.

[0008] As a result of intensive research, the inventors have found that crystallized glass having a specific composition undergoes little change in color even when recycled while containing impurities, and can maintain the same appearance as before the impurities were contained, and have completed the present invention. According to the present invention, the following crystallized glass, etc. are provided. (Configuration 1) In terms of oxide, mol %: SiO ２ Composition: 30.0% to 70.0%, Al ２ O ３ Ingredients: 2.0% to 20.0%, Na ２ O component 2.0% to 20.0%, K ２ O component 0% to 8.0%, one or more selected from MgO component and ZnO component 5.0% to 30.0%, CaO component 0% to 5.0%, TiO ２ Composition: 1.0% to 10.0%, Fe ２ O ３ Component 0.1% to 5.0%, and CoO component and Co ３ O ４ Contains 0% to 1.0% of one or more selected from the following components: ２ O ３ The content of the components is A1%, TiO ２ A glass-ceramic having a composition in which, when the content of the component is A2%, A1 x A2 is 1.0 or more. (Configuration 2) A glass-ceramic having, in mol % in terms of oxide, TiO ２ Composition: 1.3% to 8.0%, Fe ２ O ３ 0.2% to 3.0% of CoO and Co ３ O ４ The crystallized glass according to the first aspect of the present invention contains 0% to 0.5% of one or more components selected from the group consisting of: SiO ２ The composition is 40.0% to 65.0%, Al ２ O ３ Ingredients: 9.0% to 15.0%, Na ２ O component 2.5% to 15.0%, K ２The glass-ceramics according to Structure 1 or 2 contain 0.1% to 3.0% of an O component, 11.0% to 28.0% of one or more selected from an MgO component and a ZnO component, and 0.01% to 3.0% of a CaO component. (Structure 4) The glass-ceramics according to Structure 1 or 2, wherein a* is in the range of -0.10 to 1.2, b* is in the range of -2.00 to 0.30, and L* 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 using CIE illuminant D65 at an observer angle of 10°. (Reflection spectrum measurement conditions) Sample thickness: 4 mm Light-receiving angle relative to the normal to the sample surface: 8° (Configuration 5) Crystallized glass according to Configuration 1 or 2, wherein the chromaticity difference (ΔE) of the crystallized glass after adding 1000 ppm of impurities to the crystallized glass before adding the impurities is less than 1.0 in the L*a*b* color system defined in JIS Z 8781-6. (Configuration 6) In terms of oxide, SiO ２ Composition: 30.0% to 70.0%, Al ２ O ３ Ingredients: 2.0% to 20.0%, Na ２ O component 2.0% to 20.0%, K ２ O component 0% to 8.0%, one or more selected from MgO component and ZnO component 5.0% to 30.0%, CaO component 0% to 5.0%, TiO ２ Composition: 1.0% to 10.0%, Fe ２ O ３ Component 0.1% to 5.0%, and CoO component and Co ３ O ４ Contains 0% to 1.0% of one or more selected from the following components: ２ O ３ The content of the components is A1%, TiO ２ A method for recycling crystallized glass, comprising heating and melting crystallized glass in which A1 x A2 is 1.0 or more when the content of a component is A2%, and crystallizing the glass.

[0009] According to the present invention, it is possible to provide glass that exhibits little color change even when it contains impurity components.

[0010] Hereinafter, the embodiments and examples of the crystallized glass of the present invention will be described in detail, but the present invention is not limited to the following embodiments and examples, and can be practiced by making appropriate modifications within the scope of the object of the present invention.

[0011] [Glass-ceramics] The glass-ceramics according to one embodiment of the present invention contains, in mol % in terms of oxide, SiO ２ Composition: 30.0% to 70.0%, Al ２ O ３ Ingredients: 2.0% to 20.0%, Na ２ O component 2.0% to 20.0%, K ２ O component 0% to 8.0%, one or more selected from MgO component and ZnO component 5.0% to 30.0%, CaO component 0% to 5.0%, TiO ２ Composition: 1.0% to 10.0%, Fe ２ O ３ Component 0.1% to 5.0%, and CoO component and Co ３ O ４ The composition contains 0% to 1.0% of one or more selected from the following elements. ２ O ３ The content of the components is A1%, TiO ２ When the content of the component is A2%, A1 x A2 is 1.0 or more.

[0012] The crystallized glass according to one embodiment of the present invention shows little change in color before and after the incorporation of impurities (unintended components such as metal materials, organic materials, ceramic materials, etc.), and even if it contains impurities of about 0 to 20,000 ppm, it can maintain the same appearance as before the incorporation of impurities. Therefore, the crystallized glass is easy to recycle, and is expected to contribute to improving the recycling rate.

[0013] <Constituent Components> The constituent components of the crystallized glass of the present invention will be explained. In this specification, unless otherwise specified, the content of each component is expressed as mol% relative to the total substance amount of the glass in terms of oxide composition. Here, "composition in terms of oxide" refers to a composition in which each component contained in the glass is expressed, assuming that the oxides, composite salts, metal fluorides, etc. used as raw materials for the crystallized glass of the present invention are all decomposed and converted to oxides during melting, with the total substance amount of the oxides produced being 100 mol%. In this specification, A% to B% means A% or more and B% or less.

[0014] 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 3 or more 30%, 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 30.0% to 70.0%, may be 35.0% to 68.0%, or may be 40.0% to 65.0%.

[0015] 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 2.0% or more, this effect is excellent. On the other hand, Al ２ O ３ By setting the content of Al to 20% or less, it is possible to prevent deterioration of melting property and devitrification property. ２ O ３ The content of the component is 2.0% to 20.0%, may be 5.0% to 18.0%, or may be 9.0% to 15.0%.

[0016] 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. ２By keeping the O content at 20% or less, it is possible to prevent deterioration of chemical durability. ２ The content of the O component is 2.0% to 20.0%, may be 2.5% to 15.0%, or may be 2.8% to 13.0%. ２ The content of the O component may be 3.0% or more, or 3.5% or more.

[0017] 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 setting the content of the O component to 8.0% or less, it is possible to prevent deterioration of chemical durability. ２ The O component may be contained in a range of 8.0% or less. ２ The content of the O component may be 0.1% to 6.0%, or may be 0.1% to 3.0%. ２ The content of the O component may be 0.5% to 3.0%.

[0018] Containing 5.0% or more of one or more 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 selected from the MgO component and the ZnO component to 30.0% or less, deterioration of devitrification can be suppressed. Therefore, the content of one or more selected from the MgO component and the ZnO component is 5.0% to 30.0%. "The content of one or more 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 selected from the MgO component and the ZnO component may be 8.0% to 29.0%, or may be 11.0% to 28.0%. "Containing one or more selected from the MgO component and the ZnO component" means containing the MgO component alone, the ZnO component alone, or both the MgO component and the ZnO component, but it is preferable to contain the MgO component alone. The MgO component can also be a component that forms a crystalline phase by heat treating the raw glass before crystallization.

[0019] 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 contained in a range of 5.0% or less. The content of the CaO component may be 0.01% to 3.0%, or may be 0.1% to 2.0%.

[0020] TiO ２ The TiO component plays a role in nucleation for crystal precipitation, and contributes to lowering the viscosity of the glass-ceramics, improving chemical durability, and coloring the glass-ceramics. ２ When the content of the component is 1.0% or more, the effect is excellent. ２ By keeping the content of the component at 10.0% or less, it is possible to prevent the deterioration of devitrification. ２ The content of the component is 1.0% to 10.0%, may be 1.1% to 9.0%, or may be 1.3% to 8.0%. ２ The content of the component may be 1.4% or more, or may be 1.5% or more.

[0021] Fe ２ O ３ The component is a component that can form a crystalline phase, acts as a fining agent, and contributes to the coloring of the crystallized glass. ２ O ３ When the content of the element is 0.1% or more, the effect is excellent. ２ O ３ By keeping the content of this element at 5.0% 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 0.1% to 5.0%, may be 0.2% to 3.0%, or may be 0.3% to 2.0%.

[0022] CoO component and Co ３ O ４ One or more components selected from the group consisting of CoO+Co ３ O ４When 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 the group consisting of CoO+Co ３ O ４ By making the content of the CoO component and Co component 1.0% or less, it is possible to suppress the deterioration of devitrification and excessive coloring. ３ O ４ One or more components selected from the group consisting of CoO+Co ３ O ４ The content of the 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 ３ O ４ The content of one or more selected from the components may be 0% to 0.5%, or may be 0% to 0.1%.

[0023] In order to obtain a desired color of the glass-ceramic while having excellent resistance to devitrification, Fe ２ O ３ Components and TiO ２ The total content of the components [Fe ２ O ３ Component content + TiO ２ The content of the component may be 1.1% to 15.0%, 1.5% to 13.0%, or 2.0% to 10.0%.

[0024] In order to obtain a desired color of the glass-ceramic while having excellent resistance to devitrification, Fe ２ O ３ The content of the components is 1 mol% A and 1 mol% TiO ２ When the content of the component A2 is mol%, the lower limit of [A1 × A2] is 1.0 or more, or may be 1.1 or more, or 1.2 or more, and the upper limit of [A1 × A2] may be 20.0 or less, 15.0 or less, or 10.0 or less.

[0025] In order to obtain a desired color of the glass-ceramic while having excellent resistance to devitrification, Fe ２ O ３The content of the components is 1 mol% A and 1 mol% TiO ２ When the content of the component is A2 mol %, the value calculated from [aA1 + bA2] (where a = 2, b = 1) may be 1.5 to 20, 2.0 to 15, 2.5 to 13, or 3.0 to 10.

[0026] The crystallized glass is Sb ２ O ３ Component: SnO ２ Components and CeO ２ The composition may contain 0.005% to 3.0% (preferably 0.006% to 2.0%, more preferably 0.007% to 1.0%) of one or more selected from the following components.

[0027] The amounts of the above components can be combined as appropriate.

[0028] 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. ２ Ingredients, Al ２ O ３ Ingredients: Na ２ O component, K ２ One or more selected from the group consisting of an O component, an MgO component, and a ZnO component, a CaO component, and a TiO ２ Component: Fe ２ O ３ Ingredients: CoO + Co ３ O ４ Components and Sb ２ O ３ Component: SnO ２ Components and CeO ２The total content of one or more selected from the above components can be 90% or more, preferably 95% or more, more preferably 98% or more, and even more preferably 99% or more. These components may account for 100%. The crystallized glass may contain ZrO in an amount not impairing the effects of the present invention. ２ The amount of the component may be 0% to 5.0%, 0% to 3.0%, or 0% to 2.0%.

[0029] 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 ５ component, BaO component, SnO ２ Ingredients, Li ２ O component, SrO component, La ２ O ３ Component Y ２ O ３ Component: Nb ２ O ５ Component, Ta ２ O ５ Ingredients: WO ３ Ingredients, TeO ２ Component: Bi ２ O ３ The content of each of these components may be 0% to 5.0%, 0% to 4.5%, 0% to 2.0%, 0% or more but less than 2.0%, or 0% to 1.0%.

[0030] The crystallized glass contains Sb as a fining agent. ２ O ３ Component: SnO ２ Component, CeO ２ In addition to the ingredients, As ２ O ３ Components, F, and NO ｘ , S.O. 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.

[0031] The crystallized glass may contain other components not mentioned above, but may not contain them, as long as they do not impair the properties of the strengthened crystallized glass of the present invention. For example, metal components (including oxides of these metals) such as Nb, Gd, Yb, Lu, V, Cr, Mn, Ni, Cu, Ag, and Mo. In addition, since the use of Pb, Th, Tl, Os, Be, Cl, and Se has been reduced in recent years as harmful chemical substances, it is preferable that the crystallized glass does not substantially contain these components.

[0032] <Various Physical Properties> (Chromaticity) The crystallized glass may have a* in the range of -0.10 to 1.2, b* in the range of -2.00 to 0.30, 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 at an observer angle of 10° using CIE illuminant D65. 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.

[0033] a* may be -0.08 to 1.15, or may be -0.06 to 1.10. b* may be -1.50 to 0.25, or may be -1.00 to 0.20. L* may be 22.0 to 29.0, or may be 23.0 to 28.0.

[0034] (Color difference (ΔE)) The color difference (ΔE) of the crystallized glass after adding 1000 ppm of impurities to the crystallized glass before adding impurities in the L*a*b* color system specified in JIS Z 8781-6 may be 5.0 or less, 4.0 or less, 3.0 or less, 2.0 or less, 1.0 or less, or 0.8 or less. The color difference (ΔE) in the L*a*b* color system specified in JIS Z 8781-6 is measured and calculated by the method described in Examples.

[0035] (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 the predetermined content range, and then melt-molded to manufacture a base glass. Next, this base glass is crystallized to manufacture a crystallized glass.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] (Strengthening Method) The crystallized glass may be strengthened by various strengthening methods to form a compressive stress layer on the surface.

[0040] 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.

[0041] 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.

[0042] The strengthening method for the crystallized glass is not limited to chemical strengthening, and may be, for example, thermal strengthening or ion implantation.

[0043] [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, for example, as housings for various devices such as portable electronic devices and optical devices.

[0044] The crystallized glass according to one aspect of the present invention can be recovered from the equipment, etc., when the equipment, etc., that includes the component using the crystallized glass is used, and can be re-used 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 is suitable for recycling because it has little change in color when recycled (recycled product), and can easily obtain the same appearance and light-blocking properties as the glass before recycling.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 that contains the crystallized glass according to one aspect of the present invention (including tempered crystallized glass), heating and melting, and crystallizing.The method of melting and crystallization can be directly applied to the content described above for the crystallized glass according to one aspect of the present invention.

[0045] Examples 1 to 5, Comparative Examples 1 to 5 (1) Preparation of Raw Materials Raw materials such as oxides, hydroxides, carbonates, nitrates, fluorides, chlorides, metaphosphate compounds, etc. corresponding to the respective components of the crystallized glass were selected, and these raw materials were weighed out to obtain the compositions shown in Table 1 and mixed uniformly.

[0046] (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 base glass. The obtained base glass was subjected to heat treatment at the temperature and time shown in Table 1 to produce crystallized glass.

[0047] (3) Confirmation of Crystalline Phase The crystallized glasses of Examples 1 to 5 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 ４ or 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.

[0048] (4) Chromaticity For the crystallized glasses of Examples 1 to 5 and Comparative Examples 1 to 5, the reflectance spectra, including specular reflection, in a direction at an angle of 8° relative to the normal to the sample surface were measured using a spectrophotometer (Konica Minolta, CM-26dG). The sample thickness was 4 mm. From the obtained reflectance spectra, the chromaticity L*, a*, and b* were calculated using CIE illuminant D65 at an observer angle of 10°.

[0049] (5) Color Difference Raw materials were prepared in the same manner as in "(1) Preparation of Raw Materials" so as to have the compositions of Examples 1 to 5 and Comparative Examples 1 to 5 shown in Table 1. The raw materials were then treated with oxides containing impurity elements (Cr, ２ O ３ or Ni ２O) was added in amounts to give the concentrations shown in Table 2, and the mixture was melted in an electric furnace at 1400°C to 1500°C for 4 to 24 hours. The subsequent steps were the same as in "(2) Production of Crystallized Glass," to obtain crystallized glass. The chromaticity difference (ΔE) of the obtained crystallized glass before and after the addition of impurities was calculated in accordance with the color difference in the L*a*b* color system specified in JIS Z 8781-6. First, the crystallized glass of Examples 1 to 5 and Comparative Examples 1 to 5 after the addition of impurities was measured for L*', a*', and b*' using the same method as in "(4) Chromaticity." Next, for each crystallized glass, ΔE was calculated based on the following formulas (1) to (4) using the chromaticity L*, a*, and b* before the addition of impurities (chromaticity obtained by the method described in "(4) Chromaticity"), and the chromaticity L*', a*', and b*' after the addition of impurities. ΔE = {(ΔL*) ２ +(Δa*) ２ +(Δb*) ２} １／２ ...(1) ΔL*=L*-L*'...(2) Δa*=a*-a*'...(3) Δb*=b*-b*'...(4)

[0050]

[0051]

[0052] From Table 2, it can be seen that the crystallized glass of the present invention having a specific composition has a smaller ΔE than the crystallized glass of the comparative example, and the color change before and after the addition of impurities is suppressed. ２ O ３ and Ni ２ O) is a typical component that has a significant effect on the color tone of glass.

[0053] 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. In terms of oxide, mol %: SiO ２ Composition: 30.0% to 70.0%, Al ２ O ３ Ingredients: 2.0% to 20.0%, Na ２ O component 2.0% to 20.0%, K ２ O component 0% to 8.0%, one or more selected from MgO component and ZnO component 5.0% to 30.0%, CaO component 0% to 5.0%, TiO ２ Composition: 1.0% to 10.0%, Fe ２ O ３ Component 0.1% to 5.0%, and CoO component and Co ３ O ４ Contains 0% to 1.0% of one or more selected from the following components: ２ O ３ The content of the components is A1%, TiO ２ When the content of the component is A2%, A1 x A2 is 1.0 or more.

2. In terms of oxide, mol % is TiO ２ Composition: 1.3% to 8.0%, Fe ２ O ３ 0.2% to 3.0% of CoO and Co ３ O ４ 2. The crystallized glass according to claim 1, containing 0% to 0.5% of one or more components selected from the following:

3. In terms of oxide, mol %: SiO ２ The composition is 40.0% to 65.0%, Al ２ O ３ Ingredients: 9.0% to 15.0%, Na ２ O component 2.5% to 15.0%, K ２ 3. The crystallized glass according to claim 1, comprising 0.1% to 3.0% of an O component, 11.0% to 28.0% of one or more components selected from an MgO component and a ZnO component, and 0.01% to 3.0% of a CaO component.

4. The crystallized glass according to claim 1 or 2, wherein a* is in the range of -0.10 to 1.2, b* is in the range of -2.00 to 0.30, and L* 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° 5. The crystallized glass according to claim 1 or 2, wherein the chromaticity difference (ΔE) of the crystallized glass after adding 1000 ppm of impurities to the crystallized glass before adding the impurities is less than 1.0 in the L*a*b* color system specified in JIS Z 8781-6.

6. In terms of oxide, mol %: SiO ２ Composition: 30.0% to 70.0%, Al ２ O ３ Ingredients: 2.0% to 20.0%, Na ２ O component 2.0% to 20.0%, K ２ O component 0% to 8.0%, one or more selected from MgO component and ZnO component 5.0% to 30.0%, CaO component 0% to 5.0%, TiO ２ Composition: 1.0% to 10.0%, Fe ２ O ３ Component 0.1% to 5.0%, and CoO component and Co ３ O ４ Contains 0% to 1.0% of one or more selected from the following components: ２ O ３ The content of the components is A1%, TiO ２ A method for recycling crystallized glass, comprising heating and melting crystallized glass in which A1 x A2 is 1.0 or more when the content of a component is A2%, and crystallizing the glass.

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