Li2O-Al2O3-SiO2-based crystallized glass

Abstract

Provided is a Li2O-Al2O3-SiO2-based crystallized glass in which the yellow coloration caused by TiO2, Fe2O3, or the like is suppressed while ensuring transparency. The Li2O-Al2O3-SiO2-based crystallized glass according to the present invention is characterized by containing less than 0.5% by mass of TiO2 and having a [beta]-OH value of 0.001 to 2 / mm.

Description

[0001] This case is a divisional application with a filing date of September 6, 2021 and an application number of 202180062339.2 (PCT / JP2021 / 032579) and an invention title of "Divisional Application of Li2O-Al2O3-SiO2 System Crystallized Glass". Technical Field

[0002] The present invention relates to Li2O-Al2O3-SiO2 system crystallized glass. Specifically, it relates to a Li2O-Al2O3-SiO2 system crystallized glass, which is suitable as a substrate for high-tech products such as the front window of an oil furnace, a wood stove, a color filter, or a substrate for an image sensor, a positioning member for firing electronic components, a light diffusing plate, a crucible tube for semiconductor manufacturing, a mask for semiconductor manufacturing, an optical lens, a component for dimensional measurement, a component for communication, a component for construction, a container for chemical reaction, a top plate for electromagnetic cooking, heat-resistant tableware, a heat-resistant cover, a window glass for a fire door, a component for a celestial telescope, a component for space optics, etc. Background Art

[0003] Currently, as materials for high-tech products such as the front window of an oil furnace, a wood stove, a color filter, or a substrate for an image sensor, a positioning member for firing electronic components, a light diffusing plate, a crucible tube for semiconductor manufacturing, a mask for semiconductor manufacturing, an optical lens, a component for dimensional measurement, a component for communication, a component for construction, a container for chemical reaction, a top plate for electromagnetic cooking, heat-resistant tableware, a heat-resistant cover, a window glass for a fire door, a component for a celestial telescope, a component for space optics, etc., Li2O-Al2O3-SiO2 system crystallized glass is used. For example, Patent Documents 1 to 3 disclose Li2O-Al2O3-SiO2 system crystallized glass crystallized from Li2O-Al2O3-SiO2 system, such as the main crystal precipitation of β-quartz solid solution (Li2O·Al2O3·nSiO2 [where 2≤n≤4]), β-spodumene solid solution (Li2O·Al2O3·nSiO2 [where n≥4]).

[0004] Li2O-Al2O3-SiO2 system crystallized glass has a low thermal expansion coefficient and high mechanical strength, so it has excellent thermal properties. In addition, by appropriately adjusting the heat treatment conditions in the crystallization process, the type of precipitated crystal can be controlled, and transparent crystallized glass (precipitating β-quartz solid solution) can be easily produced.

[0005] However, in the case of manufacturing such crystallized glass, it is necessary to melt at a high temperature exceeding 1400°C. Therefore, in the clarifying agent added to the glass batch, As2O3 and Sb2O3, which generate a large amount of clarifying gas when melted at high temperature, are used. However, As2O3 and Sb2O3 are highly toxic, and there is a possibility of environmental pollution during the glass manufacturing process or when treating waste glass.

[0006] Thus, as alternative fining agents to As2O3 and Sb2O3, SnO2 and Cl have been proposed (see, for example, Patent Documents 4 and 5). Among them, Cl is likely to corrode the mold and the metal roll during glass forming, and as a result, there is a concern that the surface quality of the glass may deteriorate.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent Publication No. 39-21049

[0010] Patent Document 2: Japanese Patent Publication No. 40-20182

[0011] Patent Document 3: Japanese Unexamined Patent Application Publication No. 1-308845

[0012] Patent Document 4: Japanese Unexamined Patent Application Publication No. 11-228180

[0013] Patent Document 5: Japanese Unexamined Patent Application Publication No. 11-228181 Summary of the Invention

[0014] Technical Problem to be Solved by the Invention

[0015] Moreover, Li2O-Al2O3-SiO2-based crystallized glass has coloring caused by TiO2, Fe2O3, etc., and there are problems such as yellowing and poor appearance. In order to improve the yellow coloring of the transparent crystallized glass, it is sufficient to reduce the content of TiO2. However, when the content of TiO2 is reduced, the crystal nucleation rate in the crystallization process becomes slow, and the amount of crystal nuclei generated tends to be small. As a result, large crystals increase, making the crystallized glass turbid and liable to impair transparency.

[0016] An object of the present invention is to provide a Li2O-Al2O3-SiO2-based crystallized glass that ensures transparency and suppresses yellow coloring caused by TiO2, Fe2O3, etc.

[0017] Technical Solution for Solving the Technical Problem

[0018] The inventors of the present invention have found that the insufficient amount of crystal nuclei generated accompanying the reduction of the TiO2 content can be compensated by containing more moisture.

[0019] The Li2O-Al2O3-SiO2-based crystallized glass of the present invention is characterized in that it contains TiO2 in an amount of 0% or more and less than 0.5% by mass, and the β-OH value of the crystallized glass is 0.001 to 2 / mm. By making the β-OH value 0.001 / mm or more, even if the TiO2 content is reduced to less than 0.5% in order to improve yellow coloring, the glass can be sufficiently crystallized. The "β-OH value" is a value obtained by the following formula after measuring the transmittance of the glass using FT-IR.

[0020] β-OH value = (1 / X)log(T1 / T2)

[0021] X: Glass thickness (mm)

[0022] T1: Transmittance (%) at the reference wavelength of 3846 cm －1

[0023] T2: Minimum transmittance (%) near the hydroxyl absorption wavelength of 3600 cm －1

[0024] The Li2O-Al2O3-SiO2-based crystallized glass of the present invention preferably further contains, by mass%, 40 to 90% of SiO2, 5 to 30% of Al2O3, 1 to 10% of Li2O, 0 to 20% of SnO2, 1 to 20% of ZrO2, 0 to 10% of MgO, 0 to 10% of P2O5, and Sb2O3+As2O3 in an amount of 0% or more and less than 2%.

[0025] As described above, by making the β-OH value less than 2 / mm, even if the total amount of the clarifying agents Sb2O3 and As2O3 is reduced to less than 2%, the glass can be sufficiently clarified. In addition, "Sb2O3+As2O3" refers to the total amount of Sb2O3 and As2O3.

[0026] The Li2O-Al2O3-SiO2-based crystallized glass of the present invention preferably further contains, by mass%, 0 to 10% of Na2O, 0 to 10% of K2O, 0 to 10% of CaO, 0 to 10% of SrO, 0 to 10% of BaO, 0 to 10% of ZnO, and 0 to 10% of B2O3.

[0027] The Li2O-Al2O3-SiO2-based crystallized glass of the present invention preferably further contains Fe2O3 in an amount of 0.1% or less by mass.

[0028] The Li2O–Al2O3–SiO2 system crystallized glass of the present invention preferably has SnO2 / (SnO2+ZrO2+P2O5+TiO2+B2O3) of 0.06 or more in terms of mass ratio. Herein, "SnO2 / (SnO2+ZrO2+P2O5+TiO2+B2O3)" refers to the value obtained by dividing the content of SnO2 by the total amount of SnO2, ZrO2, P2O5, TiO2 and B2O3.

[0029] The Li2O–Al2O3–SiO2 system crystallized glass of the present invention preferably has Al2O3 / (SnO2+ZrO2) of 7.1 or less in terms of mass ratio. Herein, "Al2O3 / (SnO2+ZrO2)" refers to the value obtained by dividing the content of Al2O3 by the total amount of SnO2 and ZrO2.

[0030] The Li2O–Al2O3–SiO2 system crystallized glass of the present invention preferably has SnO2 / (SnO2+ZrO2) of 0.01 to 0.99 in terms of mass ratio. Herein, "SnO2 / (SnO2+ZrO2)" refers to the value obtained by dividing the content of SnO2 by the total amount of SnO2 and ZrO2.

[0031] The Li2O–Al2O3–SiO2 system crystallized glass of the present invention preferably contains 8% or less of Na2O+K2O+CaO+SrO+BaO in terms of mass%. Herein, "Na2O+K2O+CaO+SrO+BaO" refers to the total amount of Na2O, K2O, CaO, SrO and BaO.

[0032] The Li2O–Al2O3–SiO2 system crystallized glass of the present invention preferably has (SiO2+Al2O3) / Li2O of 20 or more in terms of mass ratio. Herein, "(SiO2+Al2O3) / Li2O" refers to the value obtained by dividing the total amount of SiO2 and Al2O3 by the content of Li2O.

[0033] The Li2O–Al2O3–SiO2 system crystallized glass of the present invention preferably has (SiO2+Al2O3) / SnO2 of 44 or more in terms of mass ratio. Herein, "(SiO2+Al2O3) / SnO2" refers to the value obtained by dividing the total amount of SiO2 and Al2O3 by the content of SnO2.

[0034] The Li2O–Al2O3–SiO2 system crystallized glass of the present invention preferably has (MgO+ZnO) / Li2O less than 0.395 or more than 0.754 in terms of mass ratio. Herein, "(MgO+ZnO) / Li2O" refers to the value obtained by dividing the total amount of MgO and ZnO by the content of Li2O.

[0035] The Li2O–Al2O3–SiO2-based crystallized glass of the present invention preferably has (Li2O + Na2O + K2O) / ZrO2 of 2.0 or less in terms of mass ratio. Herein, "(Li2O + Na2O + K2O) / ZrO2" means the value obtained by dividing the total amount of Li2O, Na2O, and K2O by the content of ZrO2.

[0036] The Li2O–Al2O3–SiO2-based crystallized glass of the present invention preferably has TiO2 / ZrO2 of 0.0001 to 5.0 in terms of mass ratio. Herein, "TiO2 / ZrO2" means the value obtained by dividing the content of TiO2 by the content of ZrO2.

[0037] The Li2O–Al2O3–SiO2-based crystallized glass of the present invention preferably has TiO2 / (TiO2 + Fe2O3) of 0.001 to 0.999 in terms of mass ratio. Herein, "TiO2 / (TiO2 + Fe2O3)" means the value obtained by dividing the content of TiO2 by the total amount of TiO2 and Fe2O3.

[0038] The Li2O–Al2O3–SiO2-based crystallized glass of the present invention preferably contains HfO2 + Ta2O5 of less than 0.05% by mass. Herein, "HfO2 + Ta2O5" means the total amount of HfO2 and Ta2O5.

[0039] The Li2O–Al2O3–SiO2-based crystallized glass of the present invention preferably contains Pt of 7 ppm or less by mass.

[0040] The Li2O–Al2O3–SiO2-based crystallized glass of the present invention preferably contains Rh of 7 ppm or less by mass.

[0041] The Li2O–Al2O3–SiO2-based crystallized glass of the present invention preferably contains Pt + Rh of 9 ppm or less by mass. Herein, "Pt + Rh" means the total amount of Pt and Rh.

[0042] The Li2O–Al2O3–SiO2-based crystallized glass of the present invention preferably has a colorless and transparent appearance.

[0043] The Li2O–Al2O3–SiO2-based crystallized glass of the present invention preferably has a thickness of 3 mm and a transmittance of 10% or more at a wavelength of 300 nm. Thus, it can be well used for various applications requiring ultraviolet transmittance.

[0044] The Li2O–Al2O3–SiO2-based crystallized glass of the present invention preferably has β-quartz solid solution precipitated as the main crystal. Thus, it is easy to obtain a crystallized glass with a low coefficient of thermal expansion.

[0045] The Li2O-Al2O3-SiO2 based crystallized glass of the present invention preferably has a thermal expansion coefficient of 30×10 －7 / °C or less in the range of 30 to 380°C. Thus, it can be well used for various applications requiring low expansibility.

[0046] The Li2O-Al2O3-SiO2 based crystallized glass of the present invention preferably has a thermal expansion coefficient of 30×10 －7 / °C or less in the range of 30 to 750°C. Thus, it can be well used for various applications requiring low expansibility in a wide temperature range.

[0047] The Li2O-Al2O3-SiO2 based crystallized glass of the present invention preferably has a thickness of 3 mm and a transmittance change rate before and after crystallization of 50% or less at a wavelength of 300 nm. Herein, the "transmittance change rate before and after crystallization" means {((transmittance before crystallization (%)) - (transmittance after crystallization (%))) / (transmittance before crystallization (%))}×100 (%).

[0048] The Li2O-Al2O3-SiO2 based crystallized glass of the present invention preferably has Al2O3 / (Li2O+(1 / 2×(MgO+ZnO)) in the range of 3.0 to 8.0 in terms of mass ratio. Herein, "Al2O3 / (Li2O+(1 / 2×(MgO+ZnO)" means the value obtained by dividing the Al2O3 content by the sum of the Li2O content and half of the total amount of MgO and ZnO.

[0049] The Li2O-Al2O3-SiO2 based crystallized glass of the present invention is characterized in that it contains more than 0% of MoO3 in terms of mass%, and the β-OH value of this crystallized glass is 0.001 to 0.5 / mm.

[0050] Effects of the Invention

[0051] According to the present invention, it is possible to provide a Li2O-Al2O3-SiO2 based crystallized glass that ensures transparency and suppresses yellow coloring caused by TiO2, Fe2O3, etc. Description of the Drawings

[0052] Figure 1 It is the transmittance curve before crystallization of Specimen No. 27.

[0053] Figure 2 It is the transmittance curve after crystallization of Specimen No. 27.

[0054] Figure 3 It is a graph showing the relationship between the β-OH value and the density of Specimens A to E.

[0055] Figure 4A graph showing the relationship between the β-OH value and the density of specimens F to J.

[0056] Figure 5 A graph showing the relationship between the β-OH value and the density of specimens K to M. Detailed implementation mode

[0057] The Li2O-Al2O3-SiO2-based crystallized glass of the present invention is characterized in that it contains TiO2 in an amount of less than 0.5% by mass, and the β-OH value of the crystallized glass is 0.001 to 2 / mm.

[0058] First, the glass composition of the Li2O-Al2O3-SiO2-based crystallized glass of the present invention will be described. In addition, in the following description of the content of each component, unless otherwise specified, "%" means "% by mass".

[0059] TiO2 is a nucleating component for precipitating crystals in the crystallization process. On the other hand, when contained in a large amount, the coloring of the glass becomes significantly stronger. In particular, zirconium titanate-based crystals containing ZrO2 and TiO2 act as crystal nuclei, but electrons transition from the valence band of oxygen as a ligand to the conduction band of zirconium and titanium as central metals (LMCT transition), participating in the coloring of the crystallized glass. In addition, when titanium remains in the residual glass phase, there may be an LMCT transition from the valence band of the SiO2 skeleton to the conduction band of tetravalent titanium in the residual glass phase. In addition, in trivalent titanium in the residual glass phase, d-d transition occurs, participating in the coloring of the crystallized glass. Furthermore, when titanium and iron coexist, coloring similar to ilmenite (FeTiO3) appears. It is also known that the yellow color becomes stronger when titanium and tin coexist. Therefore, the content of TiO2 is preferably 0% or more and less than 0.5%, 0 to 0.48%, 0 to 0.46%, 0 to 0.44%, 0 to 0.42%, 0 to 0.4%, 0 to 0.38%, 0 to 0.36%, 0 to 0.34%, 0 to 0.32%, 0 to 0.3%, 0 to 0.28%, 0 to 0.26%, 0 to 0.24%, 0 to 0.22%, 0 to 0.2%, 0 to 0.18%, 0 to 0.16%, 0 to 0.14%, 0 to 0.12%, and particularly preferably 0 to 0.1%. However, since TiO2 is easily mixed in as an impurity, if it is desired to completely remove TiO2, the raw material batch becomes expensive and the manufacturing cost tends to increase. In order to suppress the increase in manufacturing cost, the lower limit of the TiO2 content is preferably 0.0003% or more, 0.0005% or more, 0.001% or more, 0.005% or more, 0.01% or more, and particularly preferably 0.02% or more.

[0060] In the Li2O-Al2O3-SiO2-based crystallized glass of the present invention, in addition to the above components, the following components may also be contained in the glass composition.

[0061] SiO2 is a component that forms the framework of glass and constitutes the crystal of the Li2O-Al2O3-SiO2 system. The content of SiO2 is preferably 40 to 90%, 52 to 80%, 55 to 75%, 56 to 70%, 59 to 70%, 60 to 70%, 60 to 69.5%, 60.5 to 69.5%, 61 to 69.5%, 61.5 to 69.5%, 62 to 69.5%, 62.5 to 69.5%, 63 to 69.5%, and particularly preferably 63.5 to 69.5%. When the content of SiO2 is too small, the coefficient of thermal expansion tends to increase, and it becomes difficult to obtain a crystallized glass with excellent thermal shock resistance. In addition, the chemical durability tends to decrease. On the other hand, when the content of SiO2 is too large, the meltability of the glass decreases or the viscosity of the glass melt becomes high, making it difficult to clarify or difficult to form the glass, and the productivity is likely to decrease. In addition, the time required for crystallization becomes longer, and the productivity is likely to decrease.

[0062] Al2O3 is a component that forms the framework of glass and constitutes the crystal of the Li2O-Al2O3-SiO2 system. In addition, Al2O3 is a component that coordinates around the crystal nucleus to form a core-shell structure. Due to the presence of the core-shell structure, it is difficult to supply the crystal nucleus component from the outside of the shell. Therefore, the crystal nucleus is difficult to grow, and it is easy to form multiple minute crystal nuclei. The content of Al2O3 is preferably 5 to 30%, 8 to 30%, 9 to 28%, 10 to 27%, 12 to 27%, 14 to 27%, 16 to 27%, 17 to 27%, 18 to 27%, 18 to 26.5%, 18.1 to 26.5%, 19 to 26.5%, 19.5 to 26.5%, 20 to 26.5%, 20.5 to 26.5%, and particularly preferably 20.8 to 25.8%. When the content of Al2O3 is too small, the coefficient of thermal expansion tends to increase, and it becomes difficult to obtain a crystallized glass with excellent thermal shock resistance. In addition, the chemical durability tends to decrease. Moreover, the crystal nucleus becomes large, and the crystallized glass is likely to become cloudy. On the other hand, when the content of Al2O3 is too large, the meltability of the glass decreases or the viscosity of the glass melt becomes high, making it difficult to clarify or difficult to form the glass, and the productivity is likely to decrease. There is also a tendency for the crystallization of mullite to precipitate and devitrify the glass, and the crystallized glass is likely to break.

[0063] Li2O is a component that constitutes the Li2O-Al2O3-SiO2 system crystal. It has a great influence on crystallinity, reduces the viscosity of the glass, and improves the meltability and formability of the glass. The content of Li2O is preferably 1-10%, 2-10%, 2-8%, 2.5-6%, 2.8-5.5%, 2.8-5%, 3-5%, 3-4.5%, 3-4.2%, and particularly preferably 3.2-4%. When the content of Li2O is too small, there is a tendency for mullite crystals to precipitate and devitrify the glass. In addition, when the glass is crystallized, it becomes difficult to precipitate Li2O-Al2O3-SiO2 system crystals, and it is difficult to obtain a crystallized glass with excellent thermal shock resistance. Moreover, the meltability of the glass decreases or the viscosity of the glass melt becomes high, making it difficult to clarify or form the glass, and it is easy to reduce the productivity. On the other hand, when the content of Li2O is too large, the crystallinity becomes too strong, there is a tendency for the glass to devitrify easily, and the crystallized glass becomes easy to break.

[0064] SiO2, Al2O3, and Li2O are the main components of the β-quartz solid solution as the main crystal. Li2O and Al2O3 are dissolved in the SiO2 framework by compensating charges with each other. By containing these three components in an appropriate ratio, crystallization can be carried out efficiently, realizing low-cost manufacturing. (SiO2 + Al2O3) / Li2O is preferably 20 or more, 20.2 or more, 20.4 or more, 20.6 or more, 20.8 or more, and particularly preferably 21 or more in terms of mass ratio.

[0065] SnO2 is a component that acts as a fining agent. Moreover, it is also an essential component for efficiently precipitating crystals in the crystallization process. On the other hand, it is also a component that significantly enhances the coloring of glass when present in large amounts. The content of SnO2 is preferably 0 to 20%, more than 0% and 20% or less, 0.05 to 20%, 0.1 to 10%, 0.1 to 5%, 0.1 to 4%, 0.1 to 3%, 0.15 to 3%, 0.2 to 3%, 0.2 to 2.7%, 0.2 to 2.4%, 0.25 to 2.4%, 0.3 to 2.4%, 0.35 to 2.4%, 0.4 to 2.4%, 0.45 to 2.4%, 0.5 to 2.4%, 0.5 to 2.35%, 0.5 to 2.3%, 0.5 to 2.2%, 0.5 to 2.1%, 0.5 to 2.05%, 0.5 to 2%, 0.5 to 1.95%, 0.5 to 1.93%, 0.5 to 1.91%, 0.5 to 1.9%, 0.5 to 1.88%, 0.5 to 1.85%, 0.5 to 1.83%, 0.5 to 1.81%, and particularly preferably 0.5 to 1.8%. When the content of SnO2 is too low, it becomes difficult to clarify the glass, and the productivity is likely to decrease. In addition, there is a concern that sufficient crystal nuclei cannot be formed, and large crystals are precipitated, causing the glass to become cloudy or damaged. On the other hand, when the content of SnO2 is too high, there is a concern that the coloring of the crystallized glass becomes stronger. In addition, there is a tendency for the evaporation amount of SnO2 during melting to increase, resulting in an increase in the environmental load.

[0066] ZrO2 is a nucleating component used to precipitate crystals in the crystallization process. The content of ZrO2 is preferably 1 to 20%, 1 to 15%, 1 to 10%, 1 to 5%, 1.5 to 5%, 1.75 to 4.5%, 1.75 to 4.4%, 1.75 to 4.3%, 1.75 to 4.2%, 1.75 to 4.1%, 1.75 to 4%, 1.8 to 4%, 1.85 to 4%, 1.9 to 4%, 1.95 to 4%, 2 to 4%, 2.05 to 4%, 2.1 to 4%, 2.15 to 4%, 2.2 to 4%, 2.25 to 4%, 2.3 to 4%, 2.3 to 3.95%, 2.3 to 3.9%, 2.3 to 3.95%, 2.3 to 3.9%, 2.3 to 3.85%, 2.3 to 3.8%, more than 2.7% and 3.8% or less, 2.8 to 3.8%, 2.9 to 3.8%, and particularly preferably 3 to 3.8%. When the content of ZrO2 is too low, there is a concern that sufficient crystal nuclei cannot be formed, and large crystals are precipitated, causing the crystallized glass to become cloudy or damaged. On the other hand, when the content of ZrO2 is too high, large ZrO2 crystals are precipitated, making the glass prone to devitrification, or the crystallized glass is prone to breakage.

[0067] TiO2 and ZrO2 are components that respectively perform the function of crystal nuclei. Ti and Zr are elements of the same group, with similar electronegativity, ionic radius, etc. Therefore, as oxides, they are likely to have similar molecular conformations, and it is known that phase separation easily occurs at the initial stage of crystallization in the coexistence of TiO2 and ZrO2. Therefore, within the allowable range of coloring, the mass ratio of TiO2 / ZrO2 is preferably 0.0001 - 5.0, 0.0001 - 4.0, 0.0001 - 3.0, 0.0001 - 2.5, 0.0001 - 2.0, 0.0001 - 1.5, 0.0001 - 1.0, 0.0001 - 0.5, 0.0001 - 0.4, and particularly preferably 0.0001 - 0.3. When TiO2 / ZrO2 is too small, there is a tendency for the raw material batch to become expensive, increasing the manufacturing cost. When TiO2 / ZrO2 is too large, the crystal nucleus formation rate slows down, and the manufacturing cost may increase.

[0068] SnO2 + ZrO2 is preferably 1 - 30%, 1.1 - 30%, 1.1 - 27%, 1.1 - 24%, 1.1 - 21%, 1.1 - 20%, 1.1 - 17%, 1.1 - 14%, 1.1 - 11%, 1.1 - 9%, 1.1 - 7.5%, 1.4 - 7.5%, 1.8 - 7.5%, 2.0 - 7.5%, 2.2 - 7%, 2.2 - 6.4%, 2.2 - 6.2%, 2.2 - 6%, 2.3 - 6%, 2.4 - 6%, 2.5 - 6%, and particularly preferably 2.8 - 6%. When SnO2 + ZrO2 is too small, it becomes difficult to precipitate crystal nuclei and crystallization is difficult. When SnO2 + ZrO2 is too large, the crystal nuclei become larger, and the crystallized glass is prone to cloudiness.

[0069] SnO2 has the effect of promoting phase separation in the glass. In order to suppress the liquidus temperature to a lower level (suppressing the risk of devitrification due to primary phase precipitation), and to enable phase separation to occur efficiently and nucleation and crystal growth to proceed rapidly in subsequent processes, the mass ratio of SnO2 / (SnO2 + ZrO2) is preferably 0.01 - 0.99, 0.01 - 0.98, 0.01 - 0.94, 0.01 - 0.90, 0.01 - 0.86, 0.01 - 0.82, 0.01 - 0.78, 0.01 - 0.74, 0.01 - 0.70, 0.03 - 0.70, and particularly preferably 0.05 - 0.70.

[0070] In addition, SnO2 undergoes the reaction of SnO2 → SnO + 1 / 2O2 at high temperatures, releasing O2 gas into the glass melt. This reaction is known as the clarification mechanism of SnO2. However, the O2 gas released during the reaction not only has a "degassing effect" of enlarging the fine bubbles present in the glass melt and releasing them outside the glass system, but also has a "stirring effect" of mixing the glass melt. In the Li2O-Al2O3-SiO2-based crystallized glass of the present invention, the contents of SiO2 and Al2O3 account for more than half. Since these components are poorly soluble, in order to efficiently form a homogeneous glass melt, these three components need to be contained in an appropriate ratio. (SiO2 + Al2O3) / SnO2 is preferably 44 or more, 44.3 or more, 44.7 or more, 45 or more, 45.2 or more, 45.4 or more, 45.6 or more, 45.8 or more, and particularly preferably 46 or more in terms of mass ratio.

[0071] Al2O3 / (SnO2 + ZrO2) is preferably 7.1 or less, 7.05 or less, 7.0 or less, 6.95 or less, 66.9 or less, 6.85 or less, 6.8 or less, 6.75 or less, 6.7 or less, 6.65 or less, 6.6 or less, 6.55 or less, 6.5 or less, 6.45 or less, 6.4 or less, 6.35 or less, 6.3 or less, 6.25 or less, 6.2 or less, 6.15 or less, 6.1 or less, 6.05 or less, 6.0 or less, 5.98 or less, 5.95 or less, 5.92 or less, 5.9 or less, 5.8 or less, 5.7 or less, 5.6 or less, and particularly preferably 5.5 or less in terms of mass ratio. When Al2O3 / (SnO2 + ZrO2) is too large, nucleation cannot proceed efficiently, and it is difficult to crystallize efficiently. When Al2O3 / (SnO2 + ZrO2) is too small, the crystal nuclei become large, and the crystallized glass is prone to cloudiness. Therefore, the lower limit of Al2O3 / (SnO2 + ZrO2) is preferably 0.01 or more.

[0072] MgO is dissolved in the Li2O-Al2O3-SiO2 system crystal, which is a component that increases the thermal expansion coefficient of the Li2O-Al2O3-SiO2 system crystal. The content of MgO is preferably 0 to 10%, 0 to 8%, 0 to 6%, 0 to 5%, 0 to 4.5%, 0 to 4%, 0 to 3.5%, 0.02 to 3.5%, 0.05 to 3.5%, 0.08 to 3.5%, 0.1 to 3.5%, 0.1 to 3.3%, 0.1 to 3%, 0.13 to 3%, 0.15 to 3%, 0.17 to 3%, 0.19 to 3%, 0.2 to 2.9%, 0.2 to 2.7%, 0.2 to 2.5%, 0.2 to 2.3%, 0.2 to 2.2%, 0.2 to 2.1%, and particularly preferably 0.2 to 2%. When the content of MgO is too small, the thermal expansion coefficient tends to become too low. In addition, volume shrinkage occurs during crystal precipitation, and the amount of this volume shrinkage sometimes becomes too large. In addition, the difference in thermal expansion coefficient between the crystal phase and the residual glass phase after crystallization becomes large, so the crystallized glass sometimes becomes easily damaged. When the content of MgO is too large, the crystallinity becomes too strong and devitrification becomes easy, and the crystallized glass becomes easily damaged. In addition, the thermal expansion coefficient tends to become too high.

[0073] P2O5 is a component that inhibits the precipitation of coarse ZrO2 crystals. The content of P2O5 is preferably 0 to 10%, 0 to 8%, 0 to 6%, 0 to 5%, 0 to 4%, 0 to 3.5%, 0.02 to 3.5%, 0.05 to 3.5%, 0.08 to 3.5%, 0.1 to 3.5%, 0.1 to 3.3%, 0.1 to 3%, 0.13 to 3%, 0.15 to 3%, 0.17 to 3%, 0.19 to 3%, 0.2 to 2.9%, 0.2 to 2.7%, 0.2 to 2.5%, 0.2 to 2.3%, 0.2 to 2.2%, 0.2 to 2.1%, 0.2 to 2%, and particularly preferably 0.3 to 1.8%. When the content of P2O5 is too small, coarse ZrO2 crystals are likely to precipitate and the glass is likely to devitrify, and there is a case where the crystallized glass becomes easily damaged. When the content of P2O5 is too large, the precipitation amount of the Li2O-Al2O3-SiO2 system crystal decreases, and the thermal expansion coefficient tends to increase.

[0074] Na2O is a component that can be solid-dissolved in the Li2O-Al2O3-SiO2 system crystal. It is a component that has a great influence on crystallinity, reduces the viscosity of the glass, improves the meltability and formability of the glass. Moreover, it is also a component used to adjust the thermal expansion coefficient and refractive index of the crystallized glass. The content of Na2O is preferably 0 to 10%, 0 to 8%, 0 to 6%, 0 to 5%, 0 to 4.5%, 0 to 4%, 0 to 3.5%, 0 to 3%, 0 to 2.7%, 0 to 2.4%, 0 to 2.1%, 0 to 1.8%, and particularly preferably 0 to 1.5%. When the content of Na2O is excessive, the crystallinity becomes too strong, the glass becomes prone to devitrification, and the crystallized glass becomes prone to breakage. In addition, the ionic radius of the Na cation is larger than that of the constituent cations of the main crystal, such as the Li cation and the Mg cation, and it is not easy to enter the crystal. Therefore, the Na cation after crystallization is likely to remain in the residual glass (glass matrix). Therefore, when the content of Na2O is excessive, there is a tendency for the refractive index difference between the crystal phase and the residual glass to be easily generated, and the crystallized glass is prone to cloudiness. However, since Na2O is easily mixed in as an impurity, if Na2O is to be completely removed, there is a tendency for the raw material batch to become expensive and the manufacturing cost to increase. To suppress the increase in manufacturing cost, the lower limit of the Na2O content is preferably 0.0003% or more, 0.0005% or more, and particularly preferably 0.001% or more.

[0075] K2O is a component that can be solid-dissolved in the Li2O-Al2O3-SiO2 system crystal. It is a component that has a great influence on crystallinity, reduces the viscosity of the glass, improves the meltability and formability of the glass. Moreover, it is also a component used to adjust the thermal expansion coefficient and refractive index of the crystallized glass. The content of K2O is preferably 0 to 10%, 0 to 8%, 0 to 6%, 0 to 5%, 0 to 4.5%, 0 to 4%, 0 to 3.5%, 0 to 3%, 0 to 2.7%, 0 to 2.4%, 0 to 2.1%, 0 to 1.8%, 0 to 1.5%, 0 to 1.4%, 0 to 1.3%, 0 to 1.2%, 0 to 1.1%, 0 to 1%, 0 to 0.9%, and particularly preferably 0.1 to 0.8%. When the content of K2O is excessive, the crystallinity becomes too strong, the glass becomes prone to devitrification, and the crystallized glass becomes prone to breakage. In addition, the ionic radius of the K cation is larger than that of the constituent cations of the main crystal, such as the Li cation and the Mg cation, and it is not easy to enter the crystal. Therefore, the K cation after crystallization is likely to remain in the residual glass. Therefore, when the content of K2O is excessive, there is a tendency for the refractive index difference between the crystal phase and the residual glass to be easily generated, and the crystallized glass is prone to cloudiness. However, since K2O is easily mixed in as an impurity, if K2O is to be completely removed, there is a tendency for the raw material batch to become expensive and the manufacturing cost to increase. To suppress the increase in manufacturing cost, the lower limit of the K2O content is preferably 0.0003% or more, 0.0005% or more, and particularly preferably 0.001% or more.

[0076] Li2O, Na2O, K2O are components that improve the meltability and formability of glass, but when the content of these components is too much, there is a concern that the low-temperature viscosity decreases excessively and the glass flows excessively during crystallization. In addition, Li2O, Na2O, K2O are components that may deteriorate the weather resistance, water resistance, and chemical resistance of the glass before crystallization. When the glass before crystallization deteriorates due to moisture, etc., there is a concern that it is difficult to obtain the desired crystallization behavior and the desired characteristics. On the other hand, ZrO2 is a component that plays the role of a nucleating agent, which has the effect of preferential crystallization in the initial stage of crystallization and suppressing the flow of residual glass. In addition, ZrO2 can efficiently fill the interstitial part of the glass network based on SiO2 skeleton, has the effect of hindering the diffusion of protons and various drug components in the glass network, and can improve the weather resistance, water resistance, and chemical resistance of the glass before crystallization. In order to obtain a crystallized glass of the desired shape and characteristics, (Li2O+Na2O+K2O) / ZrO2 should be properly controlled. The mass ratio of (Li2O+Na2O+K2O) / ZrO2 is preferably 2.0 or less, 1.98 or less, 1.96 or less, 1.94 or less, 1.92 or less, and particularly preferably 1.90 or less.

[0077] CaO is a component that reduces the viscosity of glass and improves the meltability and formability of glass. In addition, it is also a component that adjusts the thermal expansion coefficient and refractive index of crystallized glass. The content of CaO is preferably 0-10%, 0-8%, 0-6%, 0-5%, 0-4.5%, 0-4%, 0-3.5%, 0-3%, 0-2.7%, 0-2.4%, 0-2.1%, 0-1.8%, and particularly preferably 0-1.5%. When the content of CaO is too much, the glass becomes easy to lose clarity and the crystallized glass becomes easy to break. In addition, the ionic radius of the Ca cation is larger than the constituent components of the main crystal, such as Li cations and Mg cations, and it is not easy to enter the crystallization, so the Ca cation after crystallization is easy to remain in the residual glass. Therefore, when the content of CaO is too much, there is a tendency that the refractive index difference between the crystal phase and the residual glass is easy to be generated, and the crystallized glass is easy to be turbid. However, since CaO is easily mixed in as an impurity, if you want to completely remove CaO, there is a tendency that the raw material batch becomes expensive and the manufacturing cost increases. In order to suppress an increase in production cost, the lower limit of the CaO content is preferably 0.0001% or more, 0.0003% or more, and particularly preferably 0.0005% or more.

[0078] SrO is a component that reduces the viscosity of glass, improves the meltability and formability of glass. Moreover, it is also a component that adjusts the thermal expansion coefficient and refractive index of crystallized glass. The content of SrO is preferably 0 to 10%, 0 to 8%, 0 to 6%, 0 to 5%, 0 to 4.5%, 0 to 4%, 0 to 3.5%, 0 to 3%, 0 to 2.7%, 0 to 2.4%, 0 to 2.1%, 0 to 1.8%, 0 to 1.5%, particularly preferably 0 to 1%. When the content of SrO is excessive, the glass becomes prone to devitrification, and the crystallized glass becomes prone to breakage. In addition, the ionic radius of Sr cations is larger than that of the constituent cations of the main crystal, such as Li cations and Mg cations, and it is not easy to enter the crystal. Therefore, Sr cations after crystallization are likely to remain in the residual glass. Therefore, when the content of SrO is excessive, there is a tendency for a refractive index difference to easily occur between the crystal phase and the residual glass, and the crystallized glass is prone to cloudiness. However, since SrO is easily mixed in as an impurity, if SrO is to be completely removed, there is a tendency for the raw material batch to become expensive and the manufacturing cost to increase. To suppress the increase in manufacturing cost, the lower limit of the SrO content is preferably 0.0001% or more, 0.0003% or more, particularly preferably 0.0005% or more.

[0079] BaO is a component that reduces the viscosity of glass, improves the meltability and formability of glass. Moreover, it is also a component that adjusts the thermal expansion coefficient and refractive index of crystallized glass. The content of BaO is preferably 0 to 10%, 0 to 8%, 0 to 6%, 0 to 5%, 0 to 4.5%, 0 to 4%, 0 to 3.5%, 0 to 3%, 0 to 2.7%, 0 to 2.4%, 0 to 2.1%, 0 to 1.8%, 0 to 1.5%, particularly preferably 0 to 1%. When the content of BaO is excessive, Ba-containing crystals precipitate, the glass becomes prone to devitrification, and the crystallized glass becomes prone to breakage. In addition, the ionic radius of Ba cations is larger than that of the constituent cations of the main crystal, such as Li cations and Mg cations, and it is not easy to enter the crystal. Therefore, Ba cations after crystallization are likely to remain in the residual glass. Therefore, when the content of BaO is excessive, there is a tendency for a refractive index difference to easily occur between the crystal phase and the residual glass, and the crystallized glass is prone to cloudiness. However, since BaO is easily mixed in as an impurity, if BaO is to be completely removed, there is a tendency for the raw material batch to become expensive and the manufacturing cost to increase. To suppress the increase in manufacturing cost, the lower limit of the BaO content is preferably 0.0001% or more, 0.0003% or more, particularly preferably 0.0005% or more.

[0080] MgO, CaO, SrO, and BaO are components that improve the fusibility and formability of glass. However, when the content of these components is excessive, there is a concern that the low-temperature viscosity will decrease excessively and the glass will flow excessively during crystallization. On the other hand, ZrO2 is a component that functions as a nucleating agent, and has the effect of preferentially crystallizing at the initial stage of crystallization and suppressing the flow of the remaining glass. In order to obtain a crystallized glass with a desired shape and properties, (MgO + CaO + SrO + BaO) / ZrO2 should be appropriately controlled. (MgO + CaO + SrO + BaO) / ZrO2 is preferably 0 to 3, 0 to 2.8, 0 to 2.6, 0 to 2.4, 0 to 2.2, 0 to 2.1, 0 to 2, 0 to 1.8, 0 to 1.7, 0 to 1.6, and particularly preferably 0 to 1.5 in terms of mass ratio.

[0081] Na2O, K2O, CaO, SrO, and BaO tend to remain in the remaining glass after crystallization. Therefore, when their total content is excessive, it is easy to generate a refractive index difference between the crystalline phase and the remaining glass, and the crystallized glass is likely to become cloudy. Therefore, Na2O + K2O + CaO + SrO + BaO is preferably 8% or less, 7% or less, 6% or less, 5% or less, 4.5% or less, 4% or less, 3.5% or less, 3% or less, 2.7% or less, 2.42% or less, 2.415% or less, 2.410% or less, 2.405% or less, and particularly preferably 2.4% or less.

[0082] Li2O, Na2O, K2O, MgO, CaO, SrO, and BaO are components that improve the fusibility and formability of glass. In addition, the viscosity (viscosity curve) of a glass melt containing a large amount of MgO, CaO, SrO, and BaO tends to change gently with respect to temperature, and the above-mentioned change of a glass melt containing a large amount of Li2O, Na2O, and K2O tends to become steep. When the change of the viscosity curve is too gentle, the glass will also flow after being formed into a specified shape, and it is difficult to obtain a desired shape. When the change of the viscosity curve is too steep, the glass melt solidifies during the forming process, and it is difficult to obtain a desired shape. Therefore, (MgO + CaO + SrO + BaO) / (Li2O + Na2O + K2O) should be appropriately controlled. (MgO + CaO + SrO + BaO) / (Li2O + Na2O + K2O) is preferably 0 to 2, 0 to 1.8, 0 to 1.5, 0 to 1.2, 0 to 1, 0 to 0.9, 0 to 0.8, 0 to 0.7, 0 to 0.6, 0 to 0.5, and particularly preferably 0 to 0.45 in terms of mass ratio.

[0083] ZnO is a component that is solid-soluble in the Li2O-Al2O3-SiO2 system crystal and has a great influence on crystallinity. It is also a component used to adjust the thermal expansion coefficient and refractive index of the crystallized glass. The content of ZnO is preferably 0 to 10%, 0 to 8%, 0 to 6%, 0 to 5%, 0 to 4.5%, 0 to 4%, 0 to 3.5%, 0 to 3%, 0 to 2.7%, 0 to 2.4%, 0 to 2.1%, 0 to 1.8%, 0 to 1.5%, and particularly preferably 0 to 1%. When the content of ZnO is excessive, the crystallinity becomes too strong and devitrification is likely to occur, and the glass becomes easily damaged. However, since ZnO is easily mixed in as an impurity, if ZnO is to be completely removed, there is a tendency for the raw material batch to become expensive and the manufacturing cost to increase. To suppress the increase in manufacturing cost, the lower limit of the ZnO content is preferably 0.0001% or more, 0.0003% or more, and particularly preferably 0.0005% or more.

[0084] In the Li2O-Al2O3-SiO2 system crystallized glass, Li cations, Mg cations, and Zn cations are components that are easily solid-soluble in the β-quartz solid solution, and these cations are solid-soluble in the crystal in the form of charge-compensating Al cations. Specifically, it can be considered that they are solid-soluble in the form of In this way, the ratio of Al cations to Li cations, Mg cations, and Zn cations affects the stability of the β-quartz solid solution. In the composition described in the present invention, crystallized glass can be stably obtained, and in order to make the crystallized glass close to colorless and transparent and have zero expansion, Al2O3 / (Li2O+(1 / 2×(MgO+ZnO) is preferably 3.0 to 8.0, 3.2 to 7.8, 3.4 to 7.6, 3.5 to 7.5, 3.7 to 7.5, 4.0 to 7.5, 4.3 to 7.5, 4.5 to 7.5, 4.8 to 7.5, 5.0 to 7.5, 5.5 to 7.3, 5.5 to 7.1, 5.5 to 7.0, 5.5 to 6.8, 5.5 to 6.7, 5.5 to 6.6, and particularly preferably 5.5 to 6.5 in terms of mass ratio.

[0085] Y2O3 is a component that reduces the viscosity of glass, improves the meltability and formability of glass. Moreover, it is also a component used to increase the Young's modulus of crystallized glass, adjust the thermal expansion coefficient and refractive index. The content of Y2O3 is preferably 0 to 10%, 0 to 8%, 0 to 6%, 0 to 5%, 0 to 4.5%, 0 to 4%, 0 to 3.5%, 0 to 3%, 0 to 2.7%, 0 to 2.4%, 0 to 2.1%, 0 to 1.8%, 0 to 1.5%, and particularly preferably 0 to 1%. When the content of Y2O3 is excessive, Y-containing crystals precipitate, the glass becomes prone to devitrification, and the crystallized glass becomes prone to breakage. In addition, the ionic radius of the Y cation is larger than that of the constituent components of the main crystal, such as the Li cation and Mg cation, and it is not easy to enter the crystal. Therefore, the Y cation after crystallization is likely to remain in the residual glass. Therefore, when the content of Y2O3 is excessive, there is a tendency for a refractive index difference to easily occur between the crystal phase and the residual glass, and the crystallized glass is prone to cloudiness. However, since Y2O3 is sometimes mixed in as an impurity, if one wants to completely remove Y2O3, there is a tendency for the raw material batch to become expensive and the manufacturing cost to increase. In order to suppress the increase in manufacturing cost, the lower limit of the Y2O3 content is preferably 0.0001% or more, 0.0003% or more, and particularly preferably 0.0005% or more.

[0086] In Li2O-Al2O3-SiO2 system crystallized glass, Li cations, Mg cations, and Zn cations are components that are easily dissolved in the β-quartz solid solution, and are considered to contribute less to the increase in the refractive index of the residual glass after crystallization compared to components such as Ba cations. In addition, Li2O, MgO, and ZnO function as fluxes when vitrifying the raw material glass. Therefore, it can be said that they are important components for manufacturing colorless and transparent crystallized glass at low temperatures. Li2O is a necessary component to achieve low expansion and needs to contain 1% or more. In order to achieve the desired thermal expansion coefficient, etc., a necessary amount of Li2O needs to be contained. However, when the contents of MgO and ZnO are increased correspondingly at the same time, there is a concern that the viscosity of the glass will decrease excessively. When the low-temperature viscosity decreases excessively, the softening fluidity of the glass during firing becomes too large, and it is sometimes difficult to crystallize into the desired shape. In addition, when the high-temperature viscosity decreases excessively, although the thermal burden on the manufacturing equipment is reduced, the convection speed during heating becomes faster, and there is a concern that the refractory material is easily physically eroded, etc. Therefore, it is preferable to control the content ratios of Li2O, MgO, and ZnO, and particularly preferably control the total amount of MgO and ZnO relative to Li2O, which has a high flux function. For this purpose, (MgO + ZnO) / Li2O is preferably 0.394 or less, 0.393 or less, 0.392 or less, 0.391 or less, particularly preferably reduced to 0.390 or less, or preferably 0.755 or more, 0.756 or more, 0.757 or more, 0.758 or more, and particularly preferably increased to 0.759 or more in terms of mass ratio.

[0087] B2O3 is a component that reduces the viscosity of glass, improves the meltability and formability of glass. Moreover, it is also a component that can interfere with the ease of phase separation when forming crystal nuclei. The content of B2O3 is preferably 0 to 10%, 0 to 8%, 0 to 6%, 0 to 5%, 0 to 4.5%, 0 to 4%, 0 to 3.5%, 0 to 3%, 0 to 2.7%, 0 to 2.4%, 0 to 2.1%, 0 to 1.8%, and particularly preferably 0 to 1.5%. When the content of B2O3 is excessive, the evaporation amount of B2O3 during melting increases, and the environmental load increases. However, since B2O3 is easily mixed in as an impurity, if it is desired to completely remove B2O3, there is a tendency for the raw material batch to become expensive and the manufacturing cost to increase. In order to suppress the increase in manufacturing cost, B2O3 preferably contains 0.0001% or more, 0.0003% or more, and particularly preferably contains 0.0005% or more.

[0088] In Li2O - Al2O3 - SiO2 system crystallized glass, it is known that after a phase separation region is formed in the glass before forming crystal nuclei, crystal nuclei composed of TiO2, ZrO2, etc. are formed in this phase separation region. Since SnO2, ZrO2, P2O5, TiO2, B2O3 strongly interfere with the formation of phase separation, SnO2 + ZrO2 + P2O5 + TiO2 + B2O3 is preferably 1.5 to 30%, 1.5 to 26%, 1.5 to 22%, 1.5 to 20%, 1.5 to 18%, 1.5 to 16%, 1.5 to 15%, 1.8 to 15%, 2.1 to 15%, 2.4 to 15%, 2.5 to 15%, 2.8 to 15%, 2.8 to 13%, 2.8 to 12%, 2.8 to 11%, 2.8 to 10%, 3 to 9.5%, 3 to 9.2%, and particularly preferably 3 to 9%. SnO2 / (SnO2 + ZrO2 + P2O5 + TiO2 + B2O3) is preferably 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.1 or more, 0.103 or more, 0.106 or more, 0.11 or more, 0.112 or more, 0.115 or more, 0.118 or more, 0.121 or more, 0.124 or more, 0.127 or more, 0.128 or more, and particularly preferably 0.13 or more in terms of mass ratio. When P2O5 + B2O3 + SnO2 + TiO2 + ZrO2 is too small, it becomes difficult to form a phase separation region and it becomes difficult to crystallize. When P2O5 + B2O3 + SnO2 + TiO2 + ZrO2 is excessive and / or when SnO2 / (SnO2 + ZrO2 + P2O5 + TiO2 + B2O3) is too small, the phase separation region becomes large and the crystallized glass is likely to be turbid. In addition, the upper limit of SnO2 / (SnO2 + ZrO2 + P2O5 + TiO2 + B2O3) is not particularly limited, but in reality it is 0.9 or less.

[0089] Fe2O3 is a component that enhances the coloring of glass, especially a component that significantly enhances the coloring due to its interaction with TiO2 and SnO2. The content of Fe2O3 is preferably 0.10% or less, 0.08% or less, 0.06% or less, 0.05% or less, 0.04% or less, 0.035% or less, 0.03% or less, 0.02% or less, 0.015% or less, 0.013% or less, 0.012% or less, 0.011% or less, 0.01% or less, 0.009% or less, 0.008% or less, 0.007% or less, 0.006% or less, 0.005% or less, 0.004% or less, 0.003% or less, and particularly preferably 0.002% or less. However, since Fe2O3 is easily mixed in as an impurity, if one wants to completely remove Fe2O3, there is a tendency for the raw material batch to become expensive and the manufacturing cost to increase. To suppress the increase in manufacturing cost, the lower limit of the content of Fe2O3 is preferably 0.0001% or more, 0.0002% or more, 0.0003% or more, 0.0005% or more, and particularly preferably 0.001% or more.

[0090] In the case where titanium and iron coexist, sometimes coloring similar to ilmenite (FeTiO3) appears. Especially in Li2O-Al2O3-SiO2-based crystallized glass, the components of titanium and iron that are not precipitated as crystal nuclei or main crystals after crystallization remain in the residual glass, which may promote the appearance of the above-mentioned coloring. Although the amount of these components can be reduced through composition design, since TiO2 and Fe2O3 are easily mixed in as impurities, if one wants to completely remove them, there is a tendency for the raw material batch to become expensive and the manufacturing cost to increase. Therefore, to suppress the manufacturing cost, TiO2 and Fe2O3 can be contained within the above ranges, and in order to make the manufacturing cost even lower, both components can also be contained within the allowable range of coloring. In this case, TiO2 / (TiO2 + Fe2O3) is preferably 0.001 - 0.999, 0.003 - 0.997, 0.005 - 0.995, 0.007 - 0.993, 0.009 - 0.991, 0.01 - 0.99, 0.1 - 0.9, 0.15 - 0.85, 0.2 - 0.8, 0.25 - 0.75, 0.3 - 0.7, 0.35 - 0.65, and particularly preferably 0.4 - 0.6 by mass ratio. Thus, it is easy to obtain crystallized glass with high colorless transparency at low cost.

[0091] Pt is a component that can be mixed into glass in the form of ions, colloids, metals, etc., showing yellow to brownish - tea coloring. In addition, this tendency becomes significant after crystallization. Moreover, through intensive investigation, it has been found that when Pt is mixed in, the nucleation and crystallization behavior of the crystallized glass are affected, and sometimes clouding is likely to occur. Therefore, the content of Pt is preferably 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1.6 ppm or less, 1.4 ppm or less, 1.2 ppm or less, 1 ppm or less, 0.9 ppm or less, 0.8 ppm or less, 0.7 ppm or less, 0.6 ppm or less, 0.5 ppm or less, 0.45 ppm or less, 0.40 ppm or less, 0.35 ppm or less, and particularly preferably 0.30 ppm or less. Although the mixing of Pt should be avoided as much as possible, in the case of using ordinary melting equipment, sometimes Pt components are needed to obtain homogeneous glass. Therefore, if Pt is to be completely removed, there is a tendency for the manufacturing cost to increase. When there is no adverse effect on coloring, in order to suppress the increase in manufacturing cost, the lower limit of the Pt content is preferably 0.0001 ppm or more, 0.001 ppm or more, 0.005 ppm or more, 0.01 ppm or more, 0.02 ppm or more, 0.03 ppm or more, 0.04 ppm or more, 0.05 ppm or more, 0.06 ppm or more, and particularly preferably 0.07 ppm or more. In addition, when coloring is allowed, Pt can be used as a nucleating agent to promote the precipitation of the main crystal in the same way as ZrO2 and TiO2. At this time, Pt can be used alone as a nucleating agent or in combination with other components as a nucleating agent. In addition, when Pt is used as a nucleating agent, its form is not particularly limited (colloid, metal crystal, etc.).

[0092] Rh is a component that can be mixed into glass in the form of ions, colloids, metals, etc. It will show yellow to brownish - yellow coloring like Pt and has a tendency to make the crystallized glass turbid. Therefore, the content of Rh is preferably 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1.6 ppm or less, 1.4 ppm or less, 1.2 ppm or less, 1 ppm or less, 0.9 ppm or less, 0.8 ppm or less, 0.7 ppm or less, 0.6 ppm or less, 0.5 ppm or less, 0.45 ppm or less, 0.40 ppm or less, 0.35 ppm or less, and particularly preferably 0.30 ppm or less. Although the incorporation of Rh should be avoided as much as possible, in the case of using ordinary melting equipment, sometimes Rh components are needed to obtain homogeneous glass. Therefore, if Rh is to be completely removed, there is a tendency for the manufacturing cost to increase. When there is no adverse effect on coloring, in order to suppress the increase in manufacturing cost, the lower limit of the content of Rh is preferably 0.0001 ppm or more, 0.001 ppm or more, 0.005 ppm or more, 0.01 ppm or more, 0.02 ppm or more, 0.03 ppm or more, 0.04 ppm or more, 0.05 ppm or more, 0.06 ppm or more, and particularly preferably 0.07 ppm or more. In addition, when coloring is allowed, Rh can also be used as a nucleating agent like ZrO2 and TiO2. At this time, Rh can be used alone as a nucleating agent or in combination with other components as a nucleating agent. In addition, when Rh is used as a nucleating agent to promote the precipitation of the main crystal, its form is not particularly limited (colloid, metal crystal, etc.).

[0093] In addition, Pt + Rh is preferably 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4.75 ppm or less, 4.5 ppm or less, 4.25 ppm or less, 4 ppm or less, 3.75 ppm or less, 3.5 ppm or less, 3.25 ppm or less, 3 ppm or less, 2.75 ppm or less, 2.5 ppm or less, 2.25 ppm or less, 2 ppm or less, 1.75 ppm or less, 1.5 ppm or less, 1.25 ppm or less, 1 ppm or less, 0.95 ppm or less, 0.9 ppm or less, 0.85 ppm or less, 0.8 ppm or less, 0.75 ppm or less, 0.7 ppm or less, 0.65 ppm or less, 0.60 ppm or less, 0.55 ppm or less, 0.50 ppm or less, 0.45 ppm or less, 0.40 ppm or less, 0.35 ppm or less, and particularly preferably 0.30 ppm or less. In addition, although the incorporation of Pt and Rh should be avoided as much as possible, in the case of using ordinary melting equipment, Pt and Rh components are sometimes required to obtain homogeneous glass. Therefore, if Pt and Rh are to be completely removed, there is a tendency for the manufacturing cost to increase. When there is no adverse effect on coloring, in order to suppress the increase in manufacturing cost, the lower limit of Pt + Rh is preferably 0.0001 ppm or more, 0.001 ppm or more, 0.005 ppm or more, 0.01 ppm or more, 0.02 ppm or more, 0.03 ppm or more, 0.04 ppm or more, 0.05 ppm or more, 0.06 ppm or more, and particularly preferably 0.07 ppm or more.

[0094] In addition, when developing glass raw materials, various crucibles are usually used to make glasses of various compositions. Therefore, platinum and rhodium evaporated from the crucible often exist inside the electric furnace for melting. It has been confirmed that Pt and Rh existing inside the electric furnace will be incorporated into the glass. In order to control the incorporation amount of Pt and Rh, in addition to selecting the raw materials and the material of the crucible used, the content of Pt and Rh in the glass can also be controlled by assembling a quartz lid on the crucible and implementing low-temperature or short-time melting temperature, etc.

[0095] MoO3 is a component that may be mixed in from raw materials or melting components, etc., and is a component that promotes crystallization. The content of MoO3 is preferably 0 to 10%, 0 to 8%, 0 to 6%, 0 to 5%, 0 to 4.5%, 0 to 4%, 0 to 3.5%, 0 to 3%, 0 to 2.7%, 0 to 2.4%, 0 to 2.1%, 0 to 1.8%, 0 to 1.5%, 0 to 1%, 0 to 0.5%, 0 to 0.1%, 0 to 0.05%, 0 to 0.01%, and particularly preferably 0 to 0.005%. When the content of MoO3 is excessive, Mo-containing crystals precipitate, the glass becomes prone to devitrification, and the crystallized glass becomes prone to breakage. In addition, the ionic radius of the Mo cation is larger than that of the constituent cations of the main crystal, such as Li cation and Mg cation, and it is not easy to enter the crystal. Therefore, the Mo cation after crystallization tends to remain in the residual glass. Therefore, when the content of MoO3 is excessive, there is a tendency for a refractive index difference to easily occur between the crystal phase and the residual glass, and the crystallized glass tends to become cloudy. Moreover, when the content of MoO3 is excessive, there is a concern about yellow coloring. However, since MoO3 may be mixed in as an impurity, if MoO3 is to be completely removed, the raw material batch becomes expensive and the manufacturing cost increases. To suppress the increase in manufacturing cost, the lower limit of the MoO3 content is preferably more than 0%, 0.0001% or more, 0.0003% or more, and particularly preferably 0.0005% or more.

[0096] As2O3 and Sb2O3 are highly toxic and may pollute the environment during the glass manufacturing process and when treating waste glass, etc. Therefore, Sb2O3 + As2O3 is preferably 2% or less, 1% or less, 0.7% or less, less than 0.7%, 0.65% or less, 0.6% or less, 0.55% or less, 0.5% or less, 0.45% or less, 0.4% or less, 0.35% or less, 0.3% or less, 0.25% or less, 0.2% or less, 0.15% or less, 0.1% or less, 0.05% or less, and particularly preferably substantially not contained (specifically less than 0.01% by mass). In addition, when As2O3 and Sb2O3 are contained, these components can also function as fining agents and nucleating agents.

[0097] In the case where there is no adverse effect on coloring, in addition to the above components, the Li2O–Al2O3–SiO2-based crystallized glass of the present invention may contain trace components such as H2, CO2, CO, H2O, He, Ne, Ar, N2, etc. up to 0.1% respectively. In addition, when Ag, Au, Pd, Ir, V, Cr, Sc, Ce, Pr, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, U, etc. are intentionally added to the glass, there is a tendency for the raw material cost and the manufacturing cost to increase. On the other hand, when the glass containing Ag, Au, etc. is irradiated with light or heat-treated, aggregates of these components can be formed, and crystallization is promoted starting from them. In addition, since Pd, etc. have various catalytic actions, by containing them, specific properties can be imparted to the glass or the crystallized glass. In view of such a situation, in the case of aiming to impart crystallization promotion or other functions, the above components may also be contained at 1% or less, 0.5% or less, 0.3% or less, 0.1% or less respectively, and when there is no such purpose, it is preferably 500 ppm or less, 300 ppm or less, 100 ppm or less, and particularly preferably 10 ppm or less.

[0098] In the case where there is no adverse effect on coloring, the Li2O–Al2O3–SiO2-based crystallized glass of the present invention may contain SO3, MnO, Cl2, La2O3, WO3, HfO2, Ta2O5, Nd2O3, Nb2O5, RfO2 in a total amount up to 10%. However, since the raw material batches of the above components are expensive and there is a tendency for the manufacturing cost to increase, they may not be added in the case where there is no particular need. In particular, the raw material cost of HfO2 is high, and Ta2O5 is a conflict mineral. Therefore, the total amount of these components is preferably 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less, 0.05% or less, less than 0.05%, 0.049% or less, 0.048% or less, 0.047% or less, 0.046% or less, and particularly preferably 0.045% or less in terms of mass%.

[0099] In other words, the preferred composition ranges for implementing the Li2O-Al2O3-SiO2 system crystallized glass of the present invention are as follows: SiO2: 50 - 75%, Al2O3: 10 - 30%, Li2O: 1 - 8%, SnO2: 0 - 5%, ZrO2: 1 - 5%, MgO: 0 - 10%, P2O5: 0 - 5%, TiO2: more than 0% and less than 1.5%, (Li2O + Na2O + K2O) / ZrO2: 0 - 1.5, TiO2 / (TiO2 + Fe2O3): 0.01 - 0.99, (MgO + ZnO) / Li2O: 0 - 0.8, β-OH value: 0.001 - 2 / mm; preferably as follows: SiO2: 50 - 75%, Al2O3: 10 - 30%, Li2O: 1 - 8%, SnO2: more than 0% and 5% or less, ZrO2: 1 - 5%, MgO: 0 - 10%, P2O5: 0 - 5%, TiO2: more than 0% and less than 1.5%, (Li2O + Na2O + K2O) / ZrO2: 0 - 1.5, TiO2 / (TiO2 + Fe2O3): 0.01 - 0.99, (MgO + ZnO) / Li2O: 0 - 0.8, (MgO + CaO + SrO + BaO) / (Li2O + Na2O + K2O): 0 - 0.5, β-OH value: 0.001 - 2 / mm; more preferably as follows: SiO2: 50 - 75%, Al2O3: 10 - 30%, Li2O: 1 - 8%, SnO2: more than 0% and 5% or less, ZrO2: 1 - 5%, MgO: 0 - 10%, P2O5: 0 - 5%, TiO2: more than 0% and less than 1.5%, (Li2O + Na2O + K2O) / ZrO2: 0 - 1.5, TiO2 / (TiO2 + Fe2O3): 0.01 - 0.99, (MgO + ZnO) / Li2O: 0 - 0.8, (MgO + CaO + SrO + BaO) / (Li2O + Na2O + K2O): 0 - 0.5, (MgO + CaO + SrO + BaO) / ZrO2: 0 - 2, β-OH value: 0.001 - 2 / mm, even more preferably as follows: SiO2: 50 - 75%, Al2O3: 10 - 30%, Li2O: 1 - 8%, SnO2: more than 0% and 5% or less, ZrO2: 1 - 5%, MgO: 0 - 10%, P2O5: 0 - 5%, TiO2: more than 0% and less than 1.5%, (Li2O + Na2O + K2O) / ZrO2: 0 - 1.5, TiO2 / (TiO2 + Fe2O3): 0.01 - 0.99, (MgO + ZnO) / Li2O: 0 - 0.8, (MgO + CaO + SrO + BaO) / (Li2O + Na2O + K2O): 0 - 0.5, (MgO + CaO + SrO + BaO) / ZrO2: 0 - 2, SnO2 / (SnO2 + ZrO2 + P2O5 + TiO2 + B2O3): 0.06 - 0.9, β-OH value is 0.001 - 2 / mm; More preferably as follows, SiO2: 50 - 75%, Al2O3: 10 - 30%, Li2O: 1 - 8%, SnO2: more than 0% and 5% or less, ZrO2: 1 - 5%, MgO: 0 - 10%, P2O5: 0 - 5%, TiO2: 0% or more and less than 1.5%, (Li2O + Na2O + K2O) / ZrO2: 0 - 1.5, TiO2 / (TiO2 + Fe2O3): 0.01 - 0.99, (MgO + ZnO) / Li2O: 0 - 0.8, (MgO + CaO + SrO + BaO) / (Li2O + Na2O + K2O): 0 - 0.5, (MgO + CaO + SrO + BaO) / ZrO2: 0 - 2, SnO2 / (SnO2 + ZrO2 + P2O5 + TiO2 + B2O3): 0.06 - 0.9, Pt + Rh: 0 - 5 ppm, β-OH value is 0.001 - 2 / mm; More preferably as follows, SiO2: 50 - 75%, Al2O3: 10 - 30%, Li2O: 1 - 8%, SnO2: more than 0% and 5% or less, ZrO2: 1 - 5%, MgO: 0 - 10%, P2O5: 0 - 5%, TiO2: 0% or more and less than 1.5%, (Li2O + Na2O + K2O) / ZrO2: 0 - 1.5, TiO2 / (TiO2 + Fe2O3) 0.01 - 0.99, (MgO + ZnO) / Li2O: 0 - 0.394, (MgO + CaO + SrO + BaO) / (Li2O + Na2O + K2O): 0 - 0.5, (MgO + CaO + SrO + BaO) / ZrO2: 0 - 2, SnO2 / (SnO2 + ZrO2 + P2O5 + TiO2 + B2O3): 0.06 - 0.9, Pt + Rh: 0 - 5 ppm, β-OH value is 0.001 - 2 / mm; More preferably as follows, SiO2: 50 - 75%, Al2O3: 10 - 30%, Li2O: 1 - 8%, SnO2: more than 0% and 5% or less, ZrO2: 1 - 5%, MgO: 0 - 10%, P2O5: 0 - 5%, TiO2: 0% or more and less than 1.5%, (Li2O + Na2O + K2O) / ZrO2: 0 - 1.5, TiO2 / (TiO2 + Fe2O3): 0.01 - 0.99, (MgO + ZnO) / Li2O: 0 - 0.394, (MgO + CaO + SrO + BaO) / (Li2O + Na2O + K2O): 0 - 0.5, (MgO + CaO + SrO + BaO) / ZrO2: 0 to 2, SnO2 / (SnO2 + ZrO2 + P2O5 + TiO2 + B2O3): 0.06 to 0.9, Pt + Rh: 0 to 5 ppm, HfO2 + Ta2O5: above 0% and below 0.05%, β-OH value: 0.001 to 2 / mm, Sb2O3 + As2O3: below 0.7%; Particularly preferred are as follows, SiO2: 50 to 75%, Al2O3: 10 to 30%, Li2O: 1 to 8%, SnO2: above 0% and 5% or less, ZrO2: 1 to 5%, MgO: 0 to 10%, P2O5: 0 to 5%, TiO2: above 0% and below 1.5%, (Li2O + Na2O + K2O) / ZrO2: 0 to 1.5, TiO2 / (TiO2 + Fe2O3): 0.01 to 0.99, (MgO + ZnO) / Li2O: 0 to 0.394, (MgO + CaO + SrO + BaO) / (Li2O + Na2O + K2O): 0 to 0.5, (MgO + CaO + SrO + BaO) / ZrO2: 0 to 2, SnO2 / (SnO2 + ZrO2 + P2O5 + TiO2 + B2O3): 0.06 to 0.9, Pt + Rh: 0 to 5 ppm, HfO2 + Ta2O5: above 0% and below 0.05%, β-OH value: 0.001 to 2 / mm, Sb2O3 + As2O3: below 0.7%, Al2O3 / (Li2O + (1 / 2 × (MgO + ZnO))): 5.0 to 7.5..

[0100] The appearance of the Li2O-Al2O3-SiO2-based crystallized glass of the present invention having the above composition is likely to be colorless and transparent.

[0101] The β-OH value of the Li2O-Al2O3-SiO2-based crystallized glass of the present invention is preferably 0.001 to 2 / mm, 0.01 to 1.5 / mm, 0.02 to 1.5 / mm, 0.03 to 1.2 / mm, 0.04 to 1.5 / mm, 0.05 to 1 / mm, 0.06 to 1 / mm, 0.07 to 1 / mm, 0.08 to 0.9 / mm, 0.08 to 0.85 / mm, 0.08 to 0.8 / mm, 0.08 to 0.75 / mm, 0.08 to 0.7 / mm, 0.08 to 0.65 / mm, 0.08 to 0.6 / mm, 0.08 to 0.55 / mm, 0.08 to 0.54 / mm, 0.08 to 0.53 / mm, 0.08 to 0.52 / mm, 0.08 to 0.51 / mm, and particularly preferably 0.08 to 0.5 / mm. When the β-OH value is too small, the nucleation rate in the crystallization process becomes slow, and the amount of generated nuclei tends to be small. As a result, large crystals increase, and the crystallized glass becomes turbid, easily impairing transparency. Although the reason for the crystallization to proceed by making the β-OH value large is not completely clear, it is expected that one of the reasons is that the β-OH group weakens the bond of the glass skeleton and reduces the viscosity of the glass. In addition, it is expected that one of the reasons is that components such as Zr that can function as nuclei become more mobile due to the presence of the β-OH group in the glass. When the β-OH value is too large, bubbles are likely to be generated at the interface between the glass and metal furnace parts containing Pt or the like or glass furnace parts made of refractories, etc., and the quality of the glass product is likely to be reduced. In addition, β-quartz solid solution crystals are easily converted into β-spodumene solid solution crystals, etc. Not only does the crystal grain size tend to become large, but also a refractive index difference is likely to be generated inside the crystallized glass. As a result, the crystallized glass is likely to become turbid. In addition, the β-OH value changes depending on the raw materials used, melting atmosphere, melting temperature, melting time, etc., and these conditions can be changed as needed to adjust the β-OH value.

[0102] The transmittance of the Li2O-Al2O3-SiO2 based crystallized glass of the present invention at a thickness of 3 mm and a wavelength of 200 nm is preferably 0% or more, 2.5% or more, 5% or more, 10% or more, 12% or more, 14% or more, 16% or more, 18% or more, 20% or more, 22% or more, 24% or more, 26% or more, 28% or more, 30% or more, 32% or more, 34% or more, 36% or more, 38% or more, 40% or more, 40.5% or more, 41% or more, 41.5% or more, 42% or more, 42.5% or more, 43% or more, 43.5% or more, 44% or more, 44.5% or more, and particularly preferably 45% or more. In applications where ultraviolet light needs to be transmitted, if the transmittance at a wavelength of 200 nm is too low, there is a concern that the desired transmission ability cannot be obtained. Especially in the cases of optical cleaning using an ozone lamp or the like, medical applications, exposure applications, etc. using an excimer laser, a high transmittance at a wavelength of 200 nm is preferred.

[0103] The transmittance of the Li2O-Al2O3-SiO2 based crystallized glass of the present invention at a thickness of 3 mm and a wavelength of 250 nm is preferably 0% or more, 1% or more, 2% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, 10% or more, 10.5% or more, 11% or more, 11.5% or more, 12% or more, 12.5% or more, 13% or more, 13.5% or more, 14% or more, 14.5% or more, 15% or more, 15.5% or more, and particularly preferably 16% or more. In applications where ultraviolet light needs to be transmitted, if the transmittance at a wavelength of 250 nm is too low, there is a concern that the desired transmission ability cannot be obtained. Especially in the cases of sterilization applications using a low-pressure mercury lamp or the like, processing applications using a YAG laser, etc., a high transmittance at a wavelength of 250 nm is preferred.

[0104] The transmittance of the Li2O-Al2O3-SiO2 based crystallized glass of the present invention at a thickness of 3 mm and a wavelength of 300 nm is preferably 0% or more, 2.5% or more, 5% or more, 10% or more, 12% or more, 14% or more, 16% or more, 18% or more, 20% or more, 22% or more, 24% or more, 26% or more, 28% or more, 30% or more, 32% or more, 34% or more, 36% or more, 38% or more, 40% or more, 40.5% or more, 41% or more, 41.5% or more, 42% or more, 42.5% or more, 43% or more, 43.5% or more, 44% or more, 44.5% or more, and particularly preferably 45% or more. Especially in the cases of UV curing / bonding / drying, fluorescence detection of printed matter, insect attracting applications, etc., a high transmittance at a wavelength of 300 nm is preferred.

[0105] The transmittance of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention at a thickness of 3 mm and a wavelength of 325 nm is preferably 0% or more, 2.5% or more, 5% or more, 10% or more, 12% or more, 14% or more, 16% or more, 18% or more, 20% or more, 22% or more, 24% or more, 26% or more, 28% or more, 30% or more, 32% or more, 34% or more, 36% or more, 38% or more, 40% or more, 42% or more, 44% or more, 46% or more, 48% or more, 50% or more, 52% or more, 54% or more, 56% or more, 57% or more, 58% or more, 59% or more, 60% or more, 61% or more, 62% or more, 63% or more, 64% or more, and particularly preferably 65% or more. Especially in the cases of being used for UV curing / bonding / drying, fluorescence detection of printed matter, insect attracting applications, etc., a high transmittance at a wavelength of 325 nm is preferred.

[0106] The transmittance of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention at a thickness of 3 mm and a wavelength of 350 nm is preferably 0% or more, 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 71% or more, 72% or more, 73% or more, 74% or more, 75% or more, 76% or more, 77% or more, 78% or more, 80% or more, 81% or more, 82% or more, 83% or more, and particularly preferably 84% or more. Especially in the cases of being used for processing using YAG laser, etc., a high transmittance at a wavelength of 350 nm is preferred.

[0107] The transmittance of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention at a thickness of 3 mm and a wavelength of 380 nm is preferably 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 78% or more, 80% or more, 81% or more, 82% or more, 83% or more, and particularly preferably 84% or more. If the transmittance at a wavelength of 380 nm is too low, the yellow coloring becomes stronger, and the transparency of the crystallized glass decreases, and there is a concern that the desired transmittance ability cannot be obtained.

[0108] The transmittance of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention at a thickness of 3 mm and a wavelength of 800 nm is preferably 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 78% or more, 80% or more, 81% or more, 82% or more, 83% or more, 84% or more, 85% or more, 86% or more, 87% or more, and particularly preferably 88% or more. If the transmittance at a wavelength of 800 nm is too low, it is likely to turn green. Especially in the case of medical applications such as vein authentication, a high transmittance at a wavelength of 800 nm is preferred.

[0109] The transmittance of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention at a thickness of 3 mm and a wavelength of 1200 nm is preferably 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 81% or more, 82% or more, 83% or more, 84% or more, 85% or more, 86% or more, 87% or more, 88% or more, and particularly preferably 89% or more. If the transmittance at a wavelength of 1200 nm is too low, it is likely to turn green. Especially in the case of infrared communication applications such as infrared cameras or remote controls, a high transmittance at a wavelength of 1200 nm is preferred.

[0110] The change rate of the transmittance of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention before and after crystallization at a thickness of 3 mm and a wavelength of 300 nm is preferably 50% or less, 48% or less, 46% or less, 44% or less, 42% or less, 40% or less, 38% or less, 37.5% or less, 37% or less, 36.5% or less, 36% or less, 35.5% or less, and particularly preferably 35% or less. By reducing the change rate of the transmittance before and after crystallization, the transmittance after crystallization can be predicted and controlled before crystallization, and it is easy to obtain the desired transmittance ability after crystallization. In addition, it is preferred that the change rate of the transmittance before and after crystallization is small not only at a wavelength of 300 nm but also in the entire wavelength region.

[0111] The lightness L* of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention at a thickness of 3 mm is preferably 50 or more, 60 or more, 65 or more, 70% or more, 75 or more, 80 or more, 85 or more, 90 or more, 91 or more, 92 or more, 93 or more, 94 or more, 95 or more, 96 or more, 96.1 or more, 96.3 or more, and particularly preferably 96.5 or more. When the lightness L* is too small, regardless of the magnitude of the chromaticity, there is a tendency to look dull with a grayish tint.

[0112] The chromaticity a* of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention, when the thickness is 3 mm, is preferably within ±5.0, within ±4.5, within ±4, within ±3.6, within ±3.2, within ±2.8, within ±2.4, within ±2, within ±1.8, within ±1.6, within ±1.4, within ±1.2, within ±1, within ±0.9, within ±0.8, within ±0.7, within ±0.6, and particularly preferably within ±0.5. When the lightness a* is too large in the negative direction, it tends to look green, and when it is too large in the positive direction, it tends to look red.

[0113] The chromaticity b* of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention, when the thickness is 3 mm, is preferably within ±5.0, within ±4.5, within ±4, within ±3.6, within ±3.2, within ±2.8, within ±2.4, within ±2, within ±1.8, within ±1.6, within ±1.4, within ±1.2, within ±1, within ±0.9, within ±0.8, within ±0.7, within ±0.6, and particularly preferably within ±0.5. When the lightness b* is too large in the negative direction, it tends to look blue, and when it is too large in the positive direction, it tends to look yellow.

[0114] In the state of the glass before crystallization of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention, the strain point (the temperature corresponding to a glass viscosity of about 10 14.5 dPa·s) is preferably 600 °C or higher, 605 °C or higher, 610 °C or higher, 615 °C or higher, 620 °C or higher, 630 °C or higher, 635 °C or higher, 640 °C or higher, 645 °C or higher, 650 °C or higher, and particularly preferably 655 °C or higher. If the strain point is too low, it is likely to break when forming the glass before crystallization.

[0115] In the state of the glass before crystallization of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention, the annealing point (the temperature corresponding to a glass viscosity of about 10 13 dPa·s) is preferably 680 °C or higher, 685 °C or higher, 690 °C or higher, 695 °C or higher, 700 °C or higher, 705 °C or higher, 710 °C or higher, 715 °C or higher, 720 °C or higher, and particularly preferably 725 °C or higher. If the annealing point is too low, it is likely to break when forming the glass before crystallization.

[0116] The Li2O-Al2O3-SiO2 system crystallized glass of the present invention is easily crystallized by heat treatment. Therefore, it is not easy to measure the softening point (the temperature corresponding to a glass viscosity of about 10 7.6The temperature of dPa·s). Therefore, in the Li2O−Al2O3−SiO2 system crystallized glass of the present invention, the temperature at which the slope of the thermal expansion curve of the glass before crystallization changes is used as the glass transition temperature as an alternative to the softening point. In the state of the glass before crystallization of the Li2O−Al2O3−SiO2 system crystallized glass of the present invention, the glass transition temperature is preferably 680 °C or higher, 685 °C or higher, 690 °C or higher, 695 °C or higher, 700 °C or higher, 705 °C or higher, 710 °C or higher, 715 °C or higher, 720 °C or higher, and particularly preferably 725 °C or higher. If the glass transition temperature is too low, the glass flows excessively during crystallization and it is difficult to form it into a desired shape.

[0117] The liquidus temperature of the Li2O−Al2O3−SiO2 system crystallized glass of the present invention is preferably 1540 °C or lower, 1535 °C or lower, 1530 °C or lower, 1525 °C or lower, 1520 °C or lower, 1515 °C or lower, 1510 °C or lower, 1505 °C or lower, 1500 °C or lower, 1495 °C or lower, 1490 °C or lower, 1485 °C or lower, 1480 °C or lower, 1475 °C or lower, 1470 °C or lower, 1465 °C or lower, 1460 °C or lower, 1455 °C or lower, 1450 °C or lower, 1445 °C or lower, 1440 °C or lower, 1435 °C or lower, 1430 °C or lower, 1425 °C or lower, 1420 °C or lower, 1415 °C or lower, and particularly preferably 1410 °C or lower. If the liquidus temperature is too high, devitrification is likely to occur during manufacturing. On the other hand, when it is 1480 °C or lower, it is easy to manufacture by the roll method or the like, when it is 1450 °C or lower, it is easy to manufacture by the casting method or the like, and when it is 1410 °C or lower, it is easy to manufacture by the melting method or the like.

[0118] The liquid-phase viscosity (the logarithm of the viscosity corresponding to the liquidus temperature) of the Li2O−Al2O3−SiO2 system crystallized glass of the present invention is preferably 2.70 or higher, 2.75 or higher, 2.80 or higher, 2.85 or higher, 2.90 or higher, 2.95 or higher, 3.00 or higher, 3.05 or higher, 3.10 or higher, 3.15 or higher, 3.20 or higher, 3.25 or higher, 3.30 or higher, 3.35 or higher, 3.40 or higher, 3.45 or higher, 3.50 or higher, 3.55 or higher, 3.60 or higher, 3.65 or higher, and particularly preferably 3.70 or higher. If the liquid-phase viscosity is too low, devitrification is likely to occur during manufacturing. On the other hand, when it is 3.40 or higher, it is easy to manufacture by the roll method or the like, when it is 3.50 or higher, it is easy to manufacture by the casting method or the like, and when it is 3.70 or higher, it is easy to manufacture by the melting method or the like.

[0119] The Li2O-Al2O3-SiO2 system crystallized glass of the present invention preferably has β-quartz solid solution precipitated as the main crystal. By precipitating β-quartz solid solution as the main crystal, the crystal grain size is liable to become small, so that the crystallized glass is liable to transmit visible light and the transparency is liable to be improved. Moreover, it is easy to make the thermal expansion coefficient of the glass close to zero. In addition, the Li2O-Al2O3-SiO2 system crystallized glass of the present invention precipitates β-spodumene solid solution by performing heat treatment at a temperature higher than the crystallization condition for precipitating β-quartz solid solution. The crystal grain size of β-spodumene solid solution is liable to be larger than that of β-quartz solid solution, and there is generally a tendency that the crystallized glass is liable to become cloudy when produced, but by appropriately adjusting the glass composition and firing conditions, sometimes the refractive index difference between the crystal phase containing β-spodumene solid solution and the residual glass phase can be reduced, and in this case, the crystallized glass is difficult to become cloudy. When there is no adverse effect on coloring etc., the Li2O-Al2O3-SiO2 system crystallized glass of the present invention may also contain crystals such as β-spodumene solid solution.

[0120] The thermal expansion coefficient of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention is preferably 30×10 －7 / °C or less, 25×10 －7 / °C or less, 20×10 －7 / °C or less, 18×10 －7 / °C or less, 16×10 －7 / °C or less, 14×10 －7 / °C or less, 13×10 －7 / °C or less, 12×10 －7 / °C or less, 11×10 －7 / °C or less, 10×10 －7 / °C or less, 9×10 －7 / °C or less, 8×10 －7 / °C or less, 7×10 －7 / °C or less, 6×10 －7 / °C or less, 5×10 －7 / °C or less, 4×10 －7 / °C or less, 3×10 －7 / °C or less, particularly preferably 2×10 －7 / °C or less. In addition, in the case where dimensional stability and / or thermal shock resistance are particularly required, it is preferably -5×10 －7 / °C to 5×10 －7 / °C, -3×10 －7 / °C to 3×10 －7 / °C, -2.5×10 －7 / °C to 2.5×10 －7 / °C, -2×10－7 / °C to 2×10 －7 / °C, -1.5×10 －7 / °C to 1.5×10 －7 / °C, -1×10 －7 / °C to 1×10 －7 / °C, particularly preferably -0.5×10 －7 / °C to 0.5×10 －7 / °C.

[0121] The thermal expansion coefficient of the Li2O - Al2O3 - SiO2 based crystallized glass of the present invention is preferably 30×10 －7 / °C or less, 25×10 －7 / °C or less, 20×10 －7 / °C or less, 18×10 －7 / °C or less, 16×10 －7 / °C or less, 14×10 －7 / °C or less, 13×10 －7 / °C or less, 12×10 －7 / °C or less, 11×10 －7 / °C or less, 10×10 －7 / °C or less, 9×10 －7 / °C or less, 8×10 －7 / °C or less, 7×10 －7 / °C or less, 6×10 －7 / °C or less, 5×10 －7 / °C or less, 4×10 －7 / °C or less, particularly preferably 3×10

[0122] －7 / °C or less. Additionally, in cases where dimensional stability and / or thermal shock resistance are particularly required, it is preferably -15×10 －7 / °C to 15×10 －7 / °C, -12×10 －7 / °C to 12×10 －7 / °C, -10×10 －7 / °C to 10×10 －7 / °C, -8×10 －7 / °C to 8×10 －7 / °C, -6×10 －7 / °C to 6×10 －7 / °C, -5×10 －7 / °C to 5×10 －7 / °C, -4.5×10 －7 / °C to 4.5×10 －7 / °C, -4×10 －7 / °C to 4×10 －7 / °C, -3.5×10 －7 / °C to 3.5×10 －7 / °C, -3×10 －7 / °C to 3×10 －7 / °C, -2.5×10 －7 / °C to 2.5×10 －7 / °C, -2×10 －7 / °C to 2×10 －7 / °C, -1.5×10 －7 / °C to 1.5×10 －7 / °C, -1×10 －7 / °C to 1×10 －7 / °C, particularly preferably -0.5×10 －7 / °C to 0.5×10 －7 / °C.

[0123] The Young's modulus of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention is preferably 60 to 120 GPa, 70 to 110 GPa, 75 to 110 GPa, 75 to 105 GPa, 80 to 105 GPa, and particularly preferably 80 to 100 GPa. When the Young's modulus is too low or too high, the crystallized glass becomes prone to breakage.

[0124] The rigidity modulus of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention is preferably 25 to 50 GPa, 27 to 48 GPa, 29 to 46 GPa, and particularly preferably 30 to 45 GPa. When the rigidity modulus is too low or too high, the crystallized glass becomes prone to breakage.

[0125] The Poisson's ratio of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention is preferably 0.35 or less, 0.32 or less, 0.3 or less, 0.28 or less, 0.26 or less, and particularly preferably 0.25 or less. When the Poisson's ratio is too large, the crystallized glass becomes prone to breakage.

[0126] The density of the pre-crystallization crystalline glass of the Li2O-Al2O3-SiO2 system crystallized glass of the present invention is preferably 2.30 to 2.60 g / cm 3 、2.32 to 2.58 g / cm 3 、2.34 to 2.56 g / cm 3 、2.36 to 2.54 g / cm 3 、2.38 to 2.52 g / cm 3 、2.39 to 2.51 g / cm 3 , particularly preferably 2.40 to 2.50 g / cm 3When the density of the crystalline glass is too low, the gas permeability before crystallization deteriorates, and there is a concern that the glass may be contaminated during storage. When the density of the crystalline glass is too high, the weight per unit area increases, making handling difficult.

[0127] The density of the Li2O-Al2O3-SiO2 based crystallized glass (after crystallization) of the present invention is preferably 2.40 to 2.80 g / cm 3 、2.42 to 2.78 g / cm 3 、2.44 to 2.76 g / cm 3 、2.46 to 2.74 g / cm 3 , particularly preferably 2.47 to 2.73 g / cm 3 When the density of the crystallized glass is too low, there is a concern that the gas permeability of the crystallized glass deteriorates. When the density of the crystallized glass is too high, the weight per unit area increases, making handling difficult. In addition, the density of the crystallized glass (after crystallization) is an index for judging whether the glass is sufficiently crystallized. Specifically, for the same glass, the greater the density (the greater the density difference between the original glass and the crystallized glass), the more the crystallization progresses.

[0128] The density change rate of the Li2O-Al2O3-SiO2 based crystallized glass of the present invention is defined by { (density after crystallization (g / cm 3 )) - density before crystallization (g / cm 3 )) / density before crystallization (g / cm 3 ))} × 100 (%). The density before crystallization is the density of the glass after melting and holding at 700 °C for 30 minutes and then cooling to room temperature at 3 °C / min. The density after crystallization is the density after crystallization treatment under specified conditions. The density change rate is preferably 0.01 to 10%, 0.05 to 8%, 0.1 to 8%, 0.3 to 8%, 0.5 to 8%, 0.9 to 8%, 1 to 7.8%, 1 to 7.4%, 1 to 7%, 1.2 to 7%, 1.6 to 7%, 2 to 7%, 2 to 6.8%, 2 to 6.5%, 2 to 6.3%, 2 to 6.2%, 2 to 6.1%, 2 to 6%, 2.5 to 5%, 2.6 to 4.5%, 2.8 to 3.8%. By making the density change rate before and after crystallization small, the breakage rate after crystallization can be reduced, the scattering of the glass and the glass matrix can also be reduced, and a crystallized glass with a high transmittance can be obtained. Especially in the region where the TiO2 content is less than 0.5% (especially 0.05% or less), not only can the coloring factors other than the absorption of TiO2 etc. be reduced, but also the scattering can be significantly reduced, which helps to improve the transmittance.

[0129] Chemical strengthening or the like can also be performed on the Li2O–Al2O3–SiO2-based crystallized glass of the present invention. The treatment conditions for the chemical strengthening treatment can be appropriately selected, considering the glass composition, crystallinity, type of molten salt, etc., such as the treatment time and treatment temperature. For example, in order to facilitate chemical strengthening after crystallization, a glass composition containing a relatively large amount of Na2O that can be contained in the residual glass can be selected, or the crystallinity can be intentionally reduced. In addition, the molten salt can contain an alkali metal such as Li, Na, or K alone, or can contain a plurality of them. Moreover, not only can a conventional one-stage strengthening be selected, but also a multi-stage chemical strengthening can be selected. In addition, by performing chemical strengthening or the like on the Li2O–Al2O3–SiO2-based crystallized glass of the present invention before crystallization, the Li2O content on the surface of the specimen can be reduced compared to the inside of the specimen. When such a glass is crystallized, the crystallinity on the surface of the specimen is lower than that inside the specimen, and relatively, the thermal expansion coefficient on the surface of the specimen becomes higher, and a compressive stress caused by the thermal expansion difference can be introduced into the surface of the specimen. In addition, when the crystallinity on the surface of the specimen is low, there are many glass phase transformations on the surface, and by selecting the glass composition, the chemical resistance and gas barrier properties can be improved.

[0130] A method for manufacturing the Li2O–Al2O3–SiO2-based crystallized glass of the present invention will be described below.

[0131] First, a raw material batch prepared to form a glass having the above composition is charged into a glass melting furnace and melted at 1500 to 1750 °C and then formed. In addition, when melting the glass, a flame melting method using a burner or the like, an electric melting method using electric heating, or the like can be employed. In addition, melting using laser irradiation or melting using plasma can also be used. In addition, the specimen shape can be made into a plate shape, a fibrous shape, a film shape, a powder shape, a spherical shape, a hollow shape, etc., and there is no particular limitation.

[0132] Next, the obtained crystalline glass (a glass capable of crystallization before crystallization) is heat-treated to crystallize it. As the crystallization conditions, first, nucleation is performed at 700 to 950 °C (preferably 750 to 900 °C) for 0.1 to 100 hours (preferably 1 to 60 hours), and then crystal growth is performed at 800 to 1050 °C (preferably 800 to 1000 °C) for 0.1 to 50 hours (preferably 0.2 to 10 hours). Thus, a transparent Li2O–Al2O3–SiO2-based crystallized glass in which β-quartz solid solution crystals are precipitated as the main crystals can be obtained. In addition, the heat treatment can be performed only at a specific temperature, can be performed by maintaining a temperature in two or more stages for stepwise heat treatment, or can be heated while imparting a temperature gradient.

[0133] In addition, crystallization can also be promoted by applying sound waves or irradiating electromagnetic waves. Moreover, the cooling rate of the crystallized glass that has reached a high temperature can be carried out at a specific temperature gradient or at a temperature gradient of two or more stages. When sufficient thermal shock resistance is required, it is desirable to control the cooling rate so as to sufficiently carry out the structural relaxation of the residual glass phase. Regarding the average cooling rate from 800°C to 25°C, in the part of the crystallized glass that is farthest from the surface in terms of thickness, it is preferably 3000°C / minute or less, 1000°C / minute or less, 500°C / minute or less, 400°C / minute or less, 300°C / minute or less, 200°C / minute or less, 100°C / minute or less, 50°C / minute or less, 25°C / minute or less, 10°C / minute or less, and particularly preferably 5°C / minute or less. In addition, when long-term dimensional stability is required, it is more preferably 2.5°C / minute or less, 1°C / minute or less, 0.5°C / minute or less, 0.1°C / minute or less, 0.05°C / minute or less, 0.01°C / minute or less, 0.005°C / minute or less, 0.001°C / minute or less, 0.0005°C / minute or less, and particularly preferably 0.0001°C / minute or less. Except in the case of physical strengthening treatment using air cooling, water cooling, etc., regarding the cooling rate of the crystallized glass, it is preferable that the cooling rate on the glass surface is close to the cooling rate in the part of the thickness that is farthest from the glass surface. The value obtained by dividing the cooling rate in the part of the thickness that is farthest from the surface by the cooling rate on the surface is preferably 0.0001 to 1, 0.001 to 1, 0.01 to 1, 0.1 to 1, 0.5 to 1, 0.8 to 1, 0.9 to 1, and particularly preferably 1. By being close to 1, it is difficult to generate residual deformation at all positions of the crystallized glass specimen, and long-term dimensional stability can be easily obtained. In addition, the cooling rate on the surface can be estimated by contact thermometry or a radiation thermometer, and the internal temperature can be measured by placing the crystallized glass in a high-temperature state in a cooling medium to measure the heat and the heat change rate of the cooling medium, and estimating from this numerical data, the specific heat, thermal conductivity, etc. of the crystallized glass and the cooling medium.

[0134] Example 1

[0135] The present invention will be described below based on examples, but the present invention is not limited to the following examples. Examples of the present invention (Sample Nos. 1 to 131) are shown in Tables 1 to 42.

[0136] [Table 1]

[0137]

[0138] [Table 2]

[0139]

[0140] [Table 3]

[0141]

[0142] [Table 4]

[0143]

[0144] [Table 5]

[0145]

[0146] [Table 6]

[0147]

[0148] [Table 7]

[0149]

[0150] [Table 8]

[0151]

[0152] [Table 9]

[0153]

[0154] [Table 10]

[0155]

[0156] [Table 11]

[0157]

[0158] [Table 12]

[0159]

[0160] [Table 13]

[0161]

[0162] [Table 14]

[0163]

[0164] [Table 15]

[0165]

[0166] [Table 16]

[0167]

[0168] [Table 17]

[0169]

[0170] [Table 18]

[0171]

[0172] [Table 19]

[0173]

[0174] [Table 20]

[0175]

[0176] [Table 21]

[0177]

[0178] [Table 22]

[0179]

[0180] [Table 23]

[0181]

[0182] [Table 24]

[0183]

[0184] [Table 25]

[0185]

[0186] [Table 26]

[0187]

[0188] [Table 27]

[0189]

[0190] [Table 28]

[0191]

[0192] [Table 29]

[0193]

[0194] [Table 30]

[0195]

[0196] [Table 31]

[0197]

[0198] [Table 32]

[0199]

[0200] [Table 33]

[0201]

[0202] [Table 34]

[0203]

[0204] [Table 35]

[0205]

[0206] [Table 36]

[0207]

[0208] [Table 37]

[0209]

[0210] [Table 38]

[0211]

[0212] [Table 39]

[0213]

[0214] [Table 40]

[0215]

[0216] [Table 41]

[0217]

[0218] [Table 42]

[0219]

[0220] First, in order to obtain a glass having the composition recorded in each table, each raw material is mixed in the form of oxides, hydroxides, carbonates, nitrates, etc. to obtain a glass batch (the composition recorded in each table is the analysis value of the glass actually produced). The obtained glass batch is placed in a crucible containing platinum and rhodium, a reinforced platinum crucible without rhodium, a refractory crucible or a quartz crucible, and melted at 1600°C for 4 to 100 hours, then heated to 1650 to 1680°C and melted for 0.5 to 20 hours, roll-formed into a thickness of 5 mm, and then heat-treated at 700°C for 30 minutes in a slow cooling furnace, and the slow cooling furnace is cooled to room temperature at 100°C / h to obtain crystalline glass. In addition, the above-mentioned melting is carried out by the electric melting method widely used in the development of glass raw materials.

[0221] In addition, it was confirmed that the glass composition in contact with liquid or solid can be melted by laser irradiation using the glass composition of sample No. 27. It was also confirmed that the glass composition in contact with gas can be melted by laser while the glass sample is suspended by conveying gas from the periphery of the glass sample. It was also confirmed that the glass composition in contact with gas can be melted by laser. It was also confirmed that the glass composition can be formed into a hemispherical shape, a spherical shape, a fiber shape, a powder shape, etc. by pressing, re-stretching, spraying, etc. after being pre-molten into a melt using an electric furnace, etc. In addition, it was confirmed that the glass compositions of samples No. 28 to 49 can be melted by a continuous furnace combining burner heating and electric heating, and can be formed into a block shape, a peel shape, a hollow shape, etc. by a roller method, a film method, a rod method using medium heating, etc. In addition, it was confirmed that the glass composition of sample No. 15 can be formed into a thin plate shape, a tube shape, and a valve shape by an up-drawing method, a down-drawing method, a slit method, an overflow (melting) method, a hand-blowing method, etc. Next, using the glass composition of sample No. 59, it was confirmed that the glass composition could be solidified into a plate shape by pouring a molten glass onto a liquid having a higher specific gravity than sample No. 59 and then cooling it. In addition, the glass produced by any method could be crystallized under the conditions described in the table.

[0222] The Pt and Rh contents of the specimens were analyzed using an ICP-MS apparatus (Agilent 8800 manufactured by Agilent Technologies, Inc.). First, the fabricated glass specimens were crushed, moistened with pure water, and then dissolved by adding perchloric acid, nitric acid, sulfuric acid, hydrofluoric acid, etc. After that, the Pt and Rh contents of the specimens were measured by ICP-MS. Based on the calibration curves prepared in advance using Pt and Rh solutions with known concentrations, the Pt and Rh contents of each measured specimen were obtained. The measurement modes were set as Pt: He gas / HMI (low mode), Rh: HEHe gas / HMI (medium mode), and the mass numbers were set as Pt: 198, Rh: 103. In addition, the Li2O content of the specimens was analyzed using an atomic absorption spectrometer (ContrAA600 manufactured by ANALYTIK JENA). The dissolution process of the glass specimens and the aspects of using the calibration curves were basically the same as those for Pt and Rh analysis. In addition, for other components, they can be measured using ICP-MS or atomic absorption spectrometry in the same way as Pt, Rh, and Li2O, or a glass specimen with a known concentration that has been analyzed in advance using ICP-MS or an atomic absorption spectrometer is used as a specimen for the calibration curve. After preparing a calibration curve using an XRF analyzer (ZSX PrimusIV manufactured by RIGAKU), based on this calibration curve, the actual contents of each component were obtained from the XRF analysis values of the measured specimens. When using XRF analysis, the tube voltage, tube current, exposure time, etc. were adjusted as needed according to the analyzed components.

[0223] For the crystalline glasses described in each table, after nucleation by heat treatment at 750 to 900 °C for 0.75 to 60 hours, crystallization was further carried out by heat treatment at 800 to 1000 °C for 0.25 to 3 hours. After that, heat treatment was performed at 700 °C for 30 minutes, and the temperature was lowered to room temperature at a rate of 100 °C / h. For the obtained crystallized glass, the transmittance, diffuse transmittance, lightness, chromaticity, precipitated crystals, average crystallite size, coefficient of thermal expansion, density, Young's modulus, rigidity modulus, Poisson's ratio, and appearance were evaluated. In addition, for the crystalline glass before crystallization, the transmittance, lightness, chromaticity, etc. were measured by the same method as for the crystallized glass. The β-OH value, viscosity, and liquidus temperature were also measured for the crystalline glass.

[0224] Regarding transmittance, lightness, and chromaticity, a crystallized glass plate optically polished on both sides to a thickness of 3 mm was evaluated by measurement using a spectrophotometer. The measurement was performed using a spectrophotometer V-670 manufactured by JASCO Corporation. Among them, an integrating sphere unit "ISN-723" was equipped on the V-670, and the measured transmittance was relative to the total light transmittance. In addition, the measurement wavelength range was 200 to 1500 nm, the scanning speed was 200 nm / minute, the sampling interval was 1 nm, the bandwidth was set to 5 nm in the wavelength range of 200 to 800 nm, and 20 nm in the wavelength range other than this. Before the measurement, baseline correction (aligned to 100%) and dark measurement (aligned to 0%) were performed. During the dark measurement, it was performed with the barium sulfate plate attached to the ISN-723 removed. Using the measured transmittance, the tristimulus values XYZ were calculated based on JIS Z8781-4:2013 and the corresponding international standard, and the lightness and chromaticity (light source C / 10°) were calculated from each stimulus value. In addition, the diffuse transmittance of the crystallized glass was also measured using the same model as above, with the measurement sample set in the state where the barium sulfate plate attached to the ISN-723 was removed.

[0225] The precipitated crystals were evaluated using an X-ray diffractometer (RIGAKU's fully automatic multi-purpose horizontal X-ray diffractometer Smart Lab). The scanning mode was set to 2θ / θ measurement, the scanning type was continuous scanning, the scattering and divergence slit widths were 1°, the receiving slit width was 0.2°, the measurement range was 10 to 60°, the measurement interval was 0.1°, the scanning speed was 5° / minute, and the main crystal and crystal grain size were evaluated using the analysis software installed in the same model components. As the precipitated crystal species determined as the main crystal, the β-quartz solid solution is shown as "β-Q" in the table. In addition, the average microcrystalline size of the main crystal was calculated based on the Debye-Scherrer method using the measured X-ray diffraction peak. In addition, in the measurement for calculating the average microcrystalline size, the scanning speed was 1° / minute.

[0226] The coefficient of thermal expansion was evaluated from the average linear coefficient of thermal expansion measured in the temperature ranges of 30 to 380 °C and 30 to 750 °C using a crystallized glass sample processed into 20 mm × 3.8 mm φ. A dilatometer manufactured by NETZSCH was used during the measurement. In addition, using the same measuring instrument, the thermal expansion curve in the temperature range of 30 to 750 °C was measured, and its inflection point was calculated, thereby evaluating the glass transition point of the pre-crystallized crystalline glass.

[0227] Regarding Young's modulus, rigidity modulus, and Poisson's ratio, a plate-shaped specimen (40 mm × 20 mm × 20 mm) whose surface was polished using a polishing liquid dispersed with alumina powder of No. 1200 was measured at room temperature using a free resonance type elastic modulus measuring device (JE-RT3 manufactured by TECHNO LPLAS, Japan).

[0228] The density was evaluated by the Archimedes method.

[0229] The strain point and the slow cooling point were evaluated using the fiber elongation method. Among them, a fiber specimen was made of the crystalline glass by the hand-pulling method.

[0230] The β-OH value was obtained by measuring the transmittance of the glass using FT-IR Frontier (manufactured by Perkin Elmer) and using the following formula. In addition, the scanning speed was 100 μm / min, and the sampling interval was 1 cm －1 , and the number of scans was set to 10 times for each measurement.

[0231] β-OH value = (1 / X)log10(T1 / T2)

[0232] X: Glass thickness (mm)

[0233] T1: Transmittance (%) at the reference wavelength of 3846 cm －1

[0234] T2: Minimum transmittance (%) near the hydroxyl absorption wavelength of 3600 cm －1

[0235] The high-temperature viscosity was evaluated using the platinum ball up-pulling method. During the evaluation, the massive glass specimen was broken into appropriate sizes and put into an alumina crucible in such a way as to minimize the entrainment of air bubbles. After that, the alumina crucible was heated to make the specimen into a molten state, and the glass viscosity measurement values at multiple temperatures were obtained, the constants of the Vogel-Fulcher formula were calculated, the viscosity curve was made, and the temperature at each viscosity was calculated.

[0236] ​​The liquidus temperature was evaluated by the following method. First, a platinum boat measuring approximately 120×20×10 mm was filled with glass powder sized 300 to 500 microns, placed in an electric furnace, and melted at 1600 °C for 30 minutes. Then, it was transferred to an electric furnace with a linear temperature gradient and left for 20 hours to allow devitrification precipitation. After the test sample was air-cooled to room temperature, the devitrification precipitated at the interface between the platinum boat and the glass was observed, and the temperature at the devitrification precipitation site was calculated from the temperature gradient curve of the electric furnace, which was taken as the liquidus temperature. In addition, the obtained liquidus temperature was interpolated into the high-temperature viscosity curve of the glass, and the viscosity corresponding to the liquidus temperature was taken as the liquid viscosity. Additionally, from the results of X-ray diffraction, composition analysis, etc. (Hitachi scanning electron microscope S3400N TyPE2, Horiba EMAX ENERGY EX250X), it was found that the primary phase of the glass recorded in each table was mainly ZrO2.

[0237] The appearance was evaluated by visually confirming the color tone of the crystallized glass. Additionally, visual inspections were carried out against white and black backgrounds, respectively, under indoor light and sunlight (performed at 8:00, 12:00, and 16:00 on sunny and cloudy days in January, April, July, and October). The color tone was comprehensively judged from the results of each visual inspection.

[0238] As can be seen from Tables 1 to 42, the crystallized glass of Specimen Nos. 1 to 131 as examples had a colorless and transparent appearance with a high transmittance, an almost zero coefficient of thermal expansion, and sufficient crystallization. Moreover, the change rate of transmittance before and after crystallization was small.

[0239] Figure 1 is the transmittance curve before crystallization of Specimen No. 27, Figure 2 is the transmittance curve after crystallization of Specimen No. 27. From Figure 1 、 2 it can be seen that the change rate of transmittance before and after crystallization was small.

[0240] In addition, when the crystallized glass of Specimen No. 27 was immersed in a KNO3 melt at 475 °C for 7 hours, it was found that a compressive stress layer was formed on the surface of the specimen (compressive stress: 110 MPa, compressive depth: 10 microns).

[0241] Example 2

[0242] Tables 43 and 44 show the examples of the present invention (Specimens A to J). Table 45 shows the comparative examples of the present invention (Specimens K to M).

[0243] [Table 43]

[0244]

[0245] [Table 44]

[0246]

[0247] [Table 45]

[0248]

[0249] Samples A to M described in Tables 31, 32, and 33 were produced in the same manner as in Example 1, and the β-OH value before crystallization and the density after crystallization were measured. The relationship between the β-OH value and the density of Samples A to E is shown in Figure 3 , and the relationship between the β-OH value and the density of Samples F to J is shown in Figure 4 , and the relationship between the β-OH value and the density of Samples K to M is shown in Figure 5 .

[0250] From Figure 3 , 4 it can be seen that for the crystallization glass with a small TiO2 content and which is easily colorless and transparent, the greater the β-OH value, the higher the density and the more the crystallization progresses. On the other hand, from Figure 5 it can be seen that for the crystallization glass with a large TiO2 content and which is easily colored yellow, the crystallization proceeds to the same extent regardless of the β-OH value. This result clearly shows the effect of the present invention, that is, it is possible to efficiently provide a Li2O-Al2O3-SiO2-based crystallization glass that ensures transparency and suppresses yellow coloring caused by TiO2, Fe2O3, etc. In addition, representative examples of the present invention are described in Tables 31 and 32 this time, but the same effects have also been confirmed for other examples described in the present invention. Furthermore, in the examples described in Tables 31 and 32, the crystallization temperature was fixed at a certain fixed combination, but the same effects were also confirmed for other combinations of crystallization temperatures. According to the desired firing time and the characteristics of the crystallization glass, the crystallization temperature can be arbitrarily changed.

[0251] Industrial Applicability

[0252] The Li2O-Al2O3-SiO2-based crystallization glass of the present invention can be well used for substrates for high-tech products such as front windows of oil furnaces, wood stoves, etc., color filters or substrates for image sensors, positioning members for firing electronic components, light diffusing plates, crucible tubes for semiconductor manufacturing, masks for semiconductor manufacturing, optical lenses, components for dimensional measurement, components for communication, components for construction, containers for chemical reactions, top plates for electromagnetic cooking, heat-resistant tableware, heat-resistant covers, window glass for fire doors, components for celestial telescopes, components for space optics, etc.

Claims

1. A Li2O-Al2O3-SiO2 based crystallized glass, characterized in that: it contains TiO2 in an amount of 0% or more and less than 0.5% by mass, SiO2 in an amount of 40 - 90% by mass, Al2O3 in an amount of 5 - 30% by mass, Li2O in an amount of 1 - 10% by mass, ZrO2 in an amount of 1 - 20% by mass, and the mass ratio of TiO2 / (TiO2 + Fe2O3) is 0.001 - 0.999, and the β-OH value of the crystallized glass is 0.001 - 2 / mm.

2. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1, characterized in that: it further contains SnO2 in an amount of 0 - 20% by mass, MgO in an amount of 0 - 10% by mass, P2O5 in an amount of 0 - 10% by mass, and Sb2O3 + As2O3 in an amount of 0% or more and less than 2% by mass.

3. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: it further contains Na2O in an amount of 0 - 10% by mass, K2O in an amount of 0 - 10% by mass, CaO in an amount of 0 - 10% by mass, SrO in an amount of 0 - 10% by mass, BaO in an amount of 0 - 10% by mass, ZnO in an amount of 0 - 10% by mass, and B2O3 in an amount of 0 - 10% by mass.

4. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: it further contains Fe2O3 in an amount of 0.1% or less by mass.

5. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: the mass ratio of SnO2 / (SnO2 + ZrO2 + P2O5 + TiO2 + B2O3) is 0.06 or more.

6. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: the mass ratio of Al2O3 / (SnO2 + ZrO2) is 7.1 or less.

7. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: the mass ratio of SnO2 / (SnO2 + ZrO2) is 0.01 - 0.

99.

8. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: it contains Na2O + K2O + CaO + SrO + BaO in an amount of 8% or less by mass.

9. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: the mass ratio of (SiO2 + Al2O3) / Li2O is 20 or more.

10. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: the mass ratio of (SiO2 + Al2O3) / SnO2 is 44 or more.

11. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: the mass ratio of (MgO + ZnO) / Li2O is less than 0.395 or more than 0.

754.

12. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: (Li2O + Na2O + K2O) / ZrO2 is 2.0 or less by mass ratio.

13. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: TiO2 / ZrO2 is 0.0001 to 5.0 by mass ratio.

14. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: The appearance is colorless and transparent.

15. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: The transmittance at a thickness of 3 mm and a wavelength of 300 nm is 10% or more.

16. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: β-quartz solid solution precipitates as the main crystal.

17. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: The coefficient of thermal expansion at 30 to 380 °C is 30×10 －7 / °C or less.

18. The Li2O-Al2O3-SiO2 based crystallized glass according to claim 1 or 2, characterized in that: Al2O3 / (Li2O + (1 / 2×(MgO + ZnO)) is 3.0 to 8.0 by mass ratio.

19. A Li2O-Al2O3-SiO2 based crystallized glass, characterized in that: It contains more than 0% of MoO3 by mass%, and the β-OH value of the crystallized glass is 0.001 to 0.5 / mm.

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