Crystallized glass

Abstract

Provided is an LAS-based crystallized glass having a low coefficient of thermal expansion, excellent transparency, and suppressed cost of raw material batches. This LAS-based crystallized glass is characterized by containing, in mass%, 55 to 75% of SiO2, 10 to 35% of Al2O3, 0.1 to 5% of Li2O, 0 to 10% of BaO, 0 to 10% of MgO, 0 to 5% of TiO2, 0 to 5% of ZrO2, and 0 to 5% of P2O5, and by satisfying that 8Li2O-4 (Na2O + K2O + MgO)-(BaO + ZnO) is 30% or less.

Description

Technical Field

[0001] The present invention relates to Li2O-Al2O3-SiO2 system crystallized glass (hereinafter referred to as LAS system crystallized glass). Background Art

[0002] LAS-based crystallized glass is used as a material for window glass for fire-proof doors, front windows for stoves, substrates for image sensors, setters for firing, etc.

[0003] For example, Patent Documents 1 to 4 disclose LAS-based crystallized glasses in which LAS-based crystals such as β-quartz solid solution and β-spodumene solid solution are precipitated as main crystals.

[0004] LAS series crystallized glass has a negative thermal expansion coefficient, so the thermal expansion coefficient is low, has excellent thermal properties, and precipitates a large amount of crystals, so the mechanical strength is high. In addition, by properly adjusting the heat treatment conditions in the crystallization process, the type of crystallization can be controlled, and transparent crystallized glass with low thermal expansion coefficient and high mechanical strength can be prepared.

[0005] However, in recent years, the cost of glass raw material batches has soared. Regarding lithium raw materials (Li2O), for example, with the popularization of small electronic devices such as laptops and mobile phones and electric vehicles, the demand for Li ion secondary batteries has increased compared to the supply of Li raw materials, so the price has soared.

[0006] In view of the above, in LAS system crystallized glass, the demand for controlling the cost of raw material batch is constantly increasing. However, it is not only difficult to control the cost of raw material batch but also difficult to realize transparent LAS system crystallized glass with low thermal expansion coefficient. For example, Li, which is particularly expensive, is an indispensable element, and when the content of Li2O is reduced, the precipitation amount of crystals with low thermal expansion coefficients such as β-quartz solid solution and β-spodumene solid solution decreases, so the thermal expansion coefficient of LAS system crystallized glass is easy to become high.

[0007] For example, Patent Documents 1 and 2 disclose a composition of LAS-based crystallized glass with low thermal expansion coefficient and high transparency. The glass compositions of the embodiments in these documents almost all contain about 3.5 to 4% by mass of Li2O. Specifically, the glasses of Examples 1 to 4, 6 to 7 of Patent Document 1 and Examples 1 to 8, 11 to 14, 16 to 39, 44 to 122, and 124 to 131 of Patent Document 2 contain about 3.5 to 4% by mass of Li2O, and teach that in order to achieve excellent thermal properties and transparency, the content of Li2O needs to be about 3.5 to 4% by mass.

[0008] On the other hand, Patent Document 3 discloses an embodiment in which MgO is substituted for Li2O in the composition of LAS-based crystallized glass similar to Patent Documents 1 to 2. Specifically, Examples 1 to 3, 11, and 14 to 16 disclose a transparent LAS-based crystallized glass in which the content of Li2O is reduced to less than 3.24 mass % and the content of MgO is increased to more than 1.6 mass %. These embodiments teach that containing MgO instead of Li2O is one of the effective means to reduce Li2O and maintain transparency.

[0009] In addition, Patent Document 4 also discloses a glass composition in which the content of Li2O is reduced to 2.9% or less by including ZnO and MgO in the composition of LAS-based crystallized glass.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: Japanese Patent Application Publication No. 2012-56829

[0013] Patent Document 2: International Publication No. 2022 / 054739

[0014] Patent Document 3: Japanese Patent Application Publication No. 2020-196664

[0015] Patent Document 4: Japanese Patent Application No. 2022-511634 Summary of the invention

[0016] Technical problem to be solved by the invention

[0017] However, when the content of MgO is increased, the thermal expansion coefficient tends to be higher, such as the LAS crystallized glass of patent documentation 3. In addition, all the crystallized glasses recorded in patent documentation 4 have high thermal expansion coefficients and are strongly colored because of V2O5. In addition, ZnO and Li2O, which are regarded as essential components in this patent documentation, tend to be slightly more expensive than other raw material groups other than O.

[0018] In view of the above circumstances, an object of the present invention is to provide a LAS-based crystallized glass having a low thermal expansion coefficient, excellent transparency, and reduced raw material batch cost.

[0019] Technical solutions for solving technical problems

[0020] The inventors of the present invention conducted intensive research and found that by appropriately designing the composition of LAS-based crystallized glass, it is possible to obtain LAS-based crystallized glass having a low thermal expansion coefficient, excellent transparency, and reduced raw material batch cost.

[0021] The LAS-based crystallized glass of the present invention is characterized in that, by mass%, it contains 55-75% SiO2, 10-35% Al2O3, 0.1-5% Li2O, 0-10% BaO, 0-10% MgO, 0-5% TiO2, 0-5% ZrO2, 0-5% P2O5, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) below 30%. Among them, "8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO)" refers to the value obtained by subtracting 4 times the total amount of the contents of Na2O, K2O and MgO and the total amount of the contents of BaO and ZnO from 8 times the content of Li2O.

[0022] The LAS-based crystallized glass of the present invention preferably contains, by mass%, 0.1 to 4% Li2O and 1 to 10% BaO, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) at 0 to 25%.

[0023] The LAS-based crystallized glass of the present invention preferably contains 2 to 10% of BaO by mass%.

[0024] The LAS-based crystallized glass of the present invention preferably contains more than 0 and less than 0.7% of Na2O+K2O in terms of mass %, wherein "Na2O+K2O" refers to the total amount of Na2O and K2O.

[0025] The LAS-based crystallized glass of the present invention preferably contains 0.01 to 4% of P2O5 by mass%.

[0026] The LAS-based crystallized glass of the present invention preferably contains Fe2O3 in an amount of 0 to less than 900 ppm by mass.

[0027] The LAS-based crystallized glass of the present invention preferably contains 0 to 0.2% of CaO by mass%.

[0028] The LAS-based crystallized glass of the present invention preferably satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) in the range of 12 to 25% by mass.

[0029] The LAS-based crystallized glass of the present invention preferably contains substantially no As 2 O 3 and Sb 2 O 3 .

[0030] The LAS-based crystallized glass of the present invention preferably satisfies Li2O / BaO of 2.5 or less in terms of mass ratio. Here, "Li2O / BaO" refers to the value obtained by dividing the content of Li2O by the content of BaO.

[0031] The LAS-based crystallized glass of the present invention preferably has a mass ratio of (Na2O+K2O+MgO) / BaO of less than 6. Here, "(Na2O+K2O+MgO) / BaO" refers to the value obtained by dividing the total content of Na2O, K2O and MgO by the content of BaO.

[0032] The LAS-based crystallized glass of the present invention preferably satisfies (Li2O+Na2O+K2O) / ZrO2 below 2.5 in terms of mass ratio. Wherein, "(Li2O+Na2O+K2O) / ZrO2" refers to the value obtained by dividing the total amount of the contents of Li2O, Na2O and K2O by the content of ZrO2.

[0033] The LAS-based crystallized glass of the present invention preferably contains ZnO in an amount of 0 to less than 1.1% by mass.

[0034] The LAS-based crystallized glass of the present invention preferably contains 0.1 to 3.47% Li2O by mass and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) in the range of 18 to 25%.

[0035] The LAS-based crystallized glass of the present invention preferably contains 0.1 to 1000 ppm of Pr6O in terms of mass %. 11 .

[0036] The LAS-based crystallized glass of the present invention preferably contains 0.1 to 2000 ppm of Sm2O3 in terms of mass%.

[0037] The LAS-based crystallized glass of the present invention preferably contains, by mass%, 55 to 75% SiO2, 15 to 30% Al2O3, 2.5 to 3.55% Li2O, 0 to 1.1% MgO, 0 to 1.6% CaO, 0.01 to 2.5% TiO2, 0 to 2.9% ZrO2, 0 to 2% P2O5, 30 to 2000 ppm Fe2O3, 0 to 1000 ppm V2O5, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) at 0 to 30%.

[0038] The LAS-based crystallized glass of the present invention preferably contains, by mass%, 55 to 75% SiO2, 15 to 30% Al2O3, 2.0 to 3.49% Li2O, 2.7 to 10% BaO, 0 to 4% MgO+CaO, 0.01 to 5% TiO2, 1.3 to 5% ZrO2, 30 to 10000 ppm Fe2O3, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) at 10 to 30%.

[0039] The LAS-based crystallized glass of the present invention preferably contains, by mass%, 55 to 75% SiO2, 15 to 30% Al2O3, 2.0 to 3.55% Li2O, 2.6 to 10% BaO, 0 to 4% MgO+CaO, 0.01 to 2.5% TiO2, 0 to 2.9% ZrO2, 0 to 2% P2O5, 30 to 10000 ppm Fe2O3, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) at 0 to 30%.

[0040] The LAS-based crystallized glass of the present invention preferably contains, by mass%, 55 to 68% SiO2, 15 to 30% Al2O3, 2.0 to 3.49% Li2O, 0 to 2.7% BaO, 1.5 to 5% MgO+CaO, 0.01 to 3.9% TiO2, 1.4 to 2.9% ZrO2, 0 to 2.5% P2O5, 30 to 10000 ppm Fe2O3, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) at 10 to 30%.

[0041] The LAS-based crystallized glass of the present invention preferably has a total light transmittance L* value of 90 or more when the thickness is 4 mm.

[0042] The LAS-based crystallized glass of the present invention preferably has β-quartz solid solution precipitated as a main crystal.

[0043] The LAS crystallized glass of the present invention preferably has a thermal expansion coefficient of -20×10 ﹣7 / ℃~20×10 ﹣7 / ℃.

[0044] The present invention relates to a method for manufacturing glass, which is used to manufacture any of the above-mentioned LAS-based crystallized glasses. The manufacturing method is characterized in that it includes: a step of melting glass raw materials to obtain molten glass; a step of shaping the above-mentioned molten glass; and a step of subjecting the glass obtained in the step of shaping the above-mentioned molten glass to heat treatment to crystallize it, and the method for shaping the above-mentioned molten glass is at least one selected from the group consisting of an overflow method, a float method, a down-draw method, a flow hole down-draw method, a re-draw method, a containerless method, a blowing method, a pressing method, a rolling method, a bushing method and a tube drawing method.

[0045] The crystalline glass of the present invention is characterized in that, in terms of mass %, it contains 55 to 75% SiO2, 10 to 35% Al2O3, 0.1 to 5% Li2O, 0 to 10% BaO, 0 to 10% MgO, 0 to 5% TiO2, 0 to 5% ZrO2, and 0 to 5% P2O5, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) is less than 30%.

[0046] Effects of the Invention

[0047] According to the present invention, it is possible to provide a LAS-based crystallized glass having a low thermal expansion coefficient, excellent transparency, and reduced raw material batch cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a scatter diagram obtained by plotting the thermal expansion coefficient of the LAS-based crystallized glass of each example of the present invention at 30 to 750° C. in correspondence with the value of 8Li 2 O-4(Na 2 O+K 2 O+MgO)-(BaO+ZnO). DETAILED DESCRIPTION

[0049] First, the glass composition of the LAS-based crystallized glass of the present invention will be described. In the following, the content of each component means "mass %" unless otherwise specified.

[0050] SiO2 is not only a component that forms the glass skeleton, but also a constituent of LAS system crystallization. When the content of SiO2 is too little, there is a tendency for the thermal expansion coefficient to become high, and it becomes difficult to obtain a crystallized glass with excellent thermal shock resistance. In addition, there is a tendency for chemical durability to decrease. Therefore, the content of SiO2 is preferably more than 55%, more than 57.5%, more than 60%, and more preferably more than 61%. On the other hand, when the content of SiO2 is too much, in addition to reducing the fusibility of the glass, the viscosity of the glass melt becomes high and difficult to clarify, and the glass is also difficult to shape, so the productivity is easily reduced. Therefore, the content of SiO2 is preferably less than 75%, less than 72.5%, less than 70%, less than 67.5%, and more preferably less than 65%.

[0051] Al2O3 is not only a component that forms the glass skeleton, but also a constituent component of LAS-based crystallization. In addition, Al2O3 is also a component coordinated around the crystal nucleus to form a core-shell structure. Due to the presence of a core-shell structure, it is difficult to supply the crystal nucleus component from the outside of the shell, so the crystal nucleus is difficult to become coarse and easy to form a large number of tiny crystal nuclei. As a result, tiny crystals can be uniformly precipitated in the glass. This component is also a component that reduces the high-temperature viscosity of the crystallized glass. When the content of Al2O3 is too little, there is a tendency for the thermal expansion coefficient to become high, and it is difficult to obtain a crystallized glass with excellent thermal shock resistance. Moreover, there is a tendency for chemical durability to decrease. Further, the crystal nucleus is easy to become large and the crystallized glass is easy to become turbid. Therefore, the content of Al2O3 is preferably more than 10%, more than 12.5%, more than 15%, more than 17.5%, and more preferably more than 20%. On the other hand, when the content of Al2O3 is too much, there is a tendency for crystallization of mullite and the like to precipitate and the glass to lose transparency, and the crystallized glass is easily damaged. Therefore, the content of Al2O3 is preferably 35% or less, 32.5% or less, 30% or less, 27% or less, 26% or less, 25% or less, and more preferably 24% or less.

[0052] Li2O is not only a constituent of LAS crystallization, but also a component that reduces the viscosity of glass and improves the fusibility and formability of glass. It is also a component that is easy to reduce the refractive index of crystallized glass. When the content of Li2O is too little, there is a tendency for crystallization such as mullite to precipitate and cause glass devitrification. In addition, in addition to reducing the fusibility of glass, making the viscosity of glass melt higher and difficult to clarify, it will also make glass difficult to form, and productivity is easy to reduce. In addition, since LAS crystallization becomes difficult to precipitate, there is a tendency for the thermal expansion coefficient of crystallized glass to increase, and it is difficult to obtain crystallized glass with excellent thermal shock resistance. Therefore, the content of Li2O is preferably 0.1% or more, 1% or more, 1.5% or more, 2% or more, 2.5% or more, 2.75% or more, and more preferably 3% or more. On the other hand, when the content of Li2O is too much, the crystallinity becomes too strong, and there is a tendency for glass to easily devitrify, and the crystallized glass becomes easily damaged. In addition, since Li2O is a high-priced raw material, the cost of raw material batches becomes high. Therefore, the content of Li2O is preferably 5% or less, 4% or less, 3.9% or less, 3.8% or less, 3.75% or less, 3.7% or less, 3.65% or less, 3.6% or less, 3.55% or less, 3.5% or less, 3.49% or less, 3.47% or less, and more preferably 3.45% or less.

[0053] BaO is a component that reduces the viscosity of glass and improves the fusibility and formability of glass, and is also a component for adjusting the thermal expansion coefficient and refractive index of crystallized glass. More specifically, the addition of BaO, compared with the addition of Na2O, K2O, MgO of the amount of the same substance (same mole), has a tendency to reduce the thermal expansion coefficient of the obtained crystallized glass. In addition, since the liquidus temperature is easy to become lower and the liquidus viscosity is easy to become higher, it is easy to ensure productivity. Further, there is a tendency to suppress the precipitation of aluminous garnet during the forming of crystallized glass. Since aluminous garnet system crystals grow rapidly, it is difficult to remove after formation, so it is preferably avoided to form a composition that is easy to precipitate. And, since the obtained crystallized glass is not easy to color, there is a tendency that the scattering in the glass is also easy to become smaller, so it is easy to obtain desired transparency. For this reason, the content of BaO is preferably more than 0%, more than 0.5%, more than 1%, more than 1.5%, more than 2%, more than 2.6%, more than 2.7%, more than 3%, more than 3.5%, more than 3.75%, more than 4%, more than 4.1%, more than 4.2%, more than 4.3%, more than 4.4%, more preferably more than 4.5%. On the other hand, when the content of BaO is too much, owing to the crystallization containing Ba, glass becomes easy to devitrification, so crystallized glass becomes easy to break. Therefore, the content of BaO is preferably less than 10%, less than 9.5%, less than 9%, less than 8.5%, less than 8%, less than 7.5%, less than 7%, less than 6.5%, more preferably less than 6%. It should be noted that BaO raw materials tend to be more expensive than MgO raw materials and CaO raw materials, which are also used to adjust the viscosity of glass like BaO. Therefore, if the cost of the raw material batch can be controlled lower, it can also be set to less than 4%, less than 3%, less than 2.8%, less than 2.7%, less than 2.4%, less than 2.2%, less than 2%, or less than 1.75%.

[0054] Li2O is not only a constituent of LAS system crystallization, but also a component that reduces the viscosity of glass and improves the fusibility and formability of glass. When its content is too much, liquidus viscosity becomes too low, and there is a tendency to be difficult to form. And, crystallinity becomes too strong, and there is a tendency that glass is easily devitrified. Therefore, crystallized glass becomes easy to be damaged, etc., and it is difficult to obtain desired characteristics. On the other hand, BaO is also a component that reduces the viscosity of glass and improves the fusibility and formability of glass, but its effect has a tendency less than Li2O. And, owing to the effect that the liquidus temperature is reduced, there is a tendency to suppress devitrification. Therefore, in order to obtain not only the devitrification of glass that can be suppressed, but also the liquidus viscosity can not be excessively reduced, and the crystallized glass with desired characteristics, it is preferably appropriately controlled Li2O / BaO (Li2The ratio of the content of O to the content of BaO). Li2O / BaO is preferably less than 400, less than 100, less than 30, less than 10, less than 5, less than 3, less than 2.5, less than 2, less than 1, less than 0.9, and more preferably less than 0.8, and is preferably greater than 0.05, greater than 0.1, greater than 0.2, and more preferably greater than 0.3.

[0055] MgO is dissolved in LAS system crystallization, improves the composition of thermal expansion coefficient of LAS system crystallization. Therefore, when the content of MgO is too much, there is a tendency that thermal expansion coefficient becomes high, and it is difficult to obtain the crystallized glass with excellent thermal shock resistance. In addition, crystallinity becomes too strong, precipitates crystals such as mullite, and glass is easy to lose transparency. Therefore, crystallized glass also has a tendency to be easy to break except being easy to be turbid. The content of MgO is preferably less than 10%, less than 5%, less than 4%, less than 3%, less than 2.5%, less than 2%, less than 1.5%, less than 1.2%, less than 1.1%, less than 1%, less than 0.8%, less than 0.6%, less than 0.5%, less than 0.4%, more preferably less than 0.3%. On the other hand, because MgO is a cheap raw material, the viscosity of glass can be reduced at a relatively low cost, therefore in the acceptable range of the rise of turbidity and thermal expansion coefficient of crystallized glass, add, thus can control manufacturing cost, and can reduce viscosity. Furthermore, it is easily mixed as an impurity during glass production, and if it is attempted to be completely removed, the cost tends to be high. Therefore, the MgO content is preferably 0% or more, 0.001% or more, 0.005% or more, and more preferably 0.01% or more.

[0056] CaO is a component that reduces the viscosity of glass and improves the fusibility and formability of glass. And it is also a component for adjusting the thermal expansion coefficient and refractive index of crystallized glass. When the content of CaO is too much, crystallized glass is easily turbid, and the thermal expansion coefficient of crystallized glass tends to become larger. Therefore, the content of CaO is preferably less than 2%, less than 1.6%, less than 1.4%, less than 1.2%, less than 1%, less than 0.5%, less than 0.2%, less than 0.15%, less than 0.1%, more preferably less than 0.075%. On the other hand, CaO is easily included in the raw material as an impurity, and if you want to remove it completely, the cost of the raw material batch is easy to become high. Therefore, the content of CaO is preferably more than 0%, more than 0.001%, more than 0.002%, more than 0.005%, more preferably more than 0.01%.

[0057] MgO and CaO are components that improve the fusibility and formability of glass. On the other hand, when their combined amount is too much, crystallized glass is prone to white turbidity, and the thermal expansion coefficient of crystallized glass is prone to become larger. Therefore, MgO+CaO is preferably 0-10%, 1.5-5%, 0-4%, 1-4%, and more preferably 1-3%. In addition, MgO and CaO have a cheap tendency compared with the BaO raw material that regulates the viscosity of glass like MgO and CaO. Therefore, when the cost of raw material batch can be controlled to be lower, the content of BaO can also be controlled, and MgO and CaO are added to improve the fusibility and formability of glass. Therefore, the content of BaO is preferably less than 4%, less than 3%, less than 2.8%, less than 2.6%, less than 2.4%, less than 2.2%, less than 2%, less than 1.75%. In this case, MgO+CaO is preferably 0% or more, 0.01% or more, 0.1% or more, 0.4% or more, 0.7% or more, 1% or more, 1.5% or more, or 2% or more, and preferably 10% or less, 5% or less, 4% or less, 3% or less, or 2.5% or less.

[0058] TiO2 is a nucleating component for crystallization in the crystallization process. On the other hand, when it is present in large amounts, the coloring of the glass is significantly enhanced. In particular, the crystallization of zirconium titanate (zirconia titanate) containing ZrO2 and TiO2 acts as a crystal nucleus, and electrons migrate (LMCT migration) from the valence band of oxygen as a ligand to the conduction band of zirconium and titanium as the central metal, affecting the coloring of the crystallized glass. In addition, when titanium remains in the residual glass phase, LMCT migration from the valence band of the SiO2 skeleton to the conduction band of the tetravalent titanium of the residual glass phase may occur. In addition, dd migration occurs in the trivalent titanium of the residual glass phase, affecting the coloring of the crystallized glass. Moreover, when titanium and iron coexist, a coloring similar to ilmenite (FeTiO3) is shown. It is also known that when titanium and tin coexist, yellow is enhanced. Therefore, TiO2 content is preferably below 5%, below 4%, below 3.9%, below 3.8%, below 3%, below 2.6%, below 2.5%, below 2.4%, below 2.2%, below 2.1%, below 2%, below 1.95%, more preferably below 1.9%.But, as mentioned above, TiO2 can become the composition of crystal nucleus, therefore when adding in the glass, crystal nucleus is easily separated out in the crystallization process.When TiO2 content is too little, crystal nucleus is separated out not enough in the crystallization process, separates out coarse beta-quartz solid solution, and crystallized glass is easily turbid.In addition, because TiO2 is easy to sneak into as impurity, if want to remove TiO2 fully, then the cost of raw material batch material is easily increased. Therefore, the lower limit of the TiO2 content is preferably 0% or more, greater than 0%, 0.001% or more, 0.01% or more, 0.1% or more, 1% or more, 1.2% or more, 1.4% or more, and more preferably 1.5% or more.

[0059] ZrO2 is a nucleating component used to precipitate crystals in the crystallization process. When the content of ZrO2 is too little, the nucleus is insufficient, and coarse crystals are easily precipitated, so the resulting crystallized glass is prone to turbidity or breakage. Therefore, the content of ZrO2 is preferably more than 0%, more than 0.5%, more than 1%, more than 1.3%, more than 1.4%, more than 1.8%, and more preferably more than 2%. On the other hand, when the content of ZrO2 is too much, coarse ZrO2 crystals are easily precipitated, and the glass is prone to devitrification, and the crystallized glass is prone to breakage. Moreover, the crystallized glass has a tendency to become turbid. Therefore, the content of ZrO2 is preferably less than 5%, less than 4.5%, less than 4%, less than 3.5%, less than 3%, less than 2.9%, and more preferably less than 2.8%.

[0060] P2O5 is a component that affects crystallization and suppresses the precipitation of coarse ZrO2 crystals. By containing P2O5, there is a tendency to improve the transmittance of crystallized glass and reduce the thermal expansion coefficient of crystallized glass. When the content of P2O5 is too little, it is easy to precipitate coarse ZrO2 crystals sometimes, and glass is easy to lose transparency, and crystallized glass is easy to break. And, it is difficult to obtain desired thermal characteristics and transparency sometimes. For this reason, the content of P2O5 is preferably more than 0%, more than 0.01%, more than 0.1%, more than 0.2%, more than 0.3%, more than 0.5%, more than 0.8%, more preferably more than 1%. On the other hand, when the content of P2O5 is too much, there is a tendency that crystallization is excessively suppressed, and it is difficult to obtain desired thermal characteristics and transparency sometimes. In addition, the raw material price of P2O5 is high, and when the content increases, there is a tendency that the cost of raw material batch becomes high. Therefore, the content of P2O5 is preferably 5% or less, 4% or less, 3% or less, 2.5% or less, 2% or less, 1.8% or less, and more preferably 1.6% or less.

[0061] Na2O is a component that affects crystallinity, reduces the viscosity of glass, and improves the fusibility and formability of glass. It is also a component for adjusting the thermal expansion coefficient and refractive index of crystallized glass. When the content of Na2O is too much, crystallinity becomes too strong, glass is easy to lose transparency, and crystallized glass is easy to break. And, because the ionic radius of Na cation is larger, it is difficult to be brought into crystallization, so the Na cation after crystallization is easy to remain in the residual glass (glass matrix). For this reason, when the content of Na2O is too much, it is easy to produce a refractive index difference between the crystalline phase and the residual glass, and there is a tendency that crystallized glass is easy to be turbid. Therefore, the content of Na2O is preferably less than 1%, less than 0.9%, less than 0.7%, less than 0.5%, less than 0.3%, less than 0.2%, and more preferably 0.15%. However, because Na2O is easy to be mixed in as impurities, if you want to remove Na2O completely, there is a tendency that the cost of raw material batch becomes high. In order to suppress the increase in the cost of the raw material batch, the lower limit of the content of Na2O is preferably 0% or more, 0.0003% or more, 0.0005% or more, and particularly preferably 0.001% or more.

[0062] K2O is a component that affects crystallinity, reduces glass viscosity, and improves the meltability and formability of glass. It is also a component used to adjust the thermal expansion coefficient and refractive index of crystallized glass. When the content of K2O is too much, crystallinity becomes too strong, glass is easy to lose clarity, and crystallized glass is easy to break. Moreover, since the ionic radius of K cations is large, it is difficult to be brought into crystallization, so the K cations after crystallization are easy to remain in the residual glass. Therefore, when the content of K2O is too much, a refractive index difference is easy to occur between the crystalline phase and the residual glass, and there is a tendency that the crystallized glass is easy to become turbid. Therefore, the content of K2O is preferably less than 1%, less than 0.9%, less than 0.7%, less than 0.5%, less than 0.3%, less than 0.2%, less than 0.1%, less than 0.07%, and more preferably less than 0.04%. However, since K2O is easy to be mixed in as an impurity, if you want to completely remove K2O, there is a tendency that the cost of the raw material batch becomes high. In order to suppress an increase in the cost of the raw material batch, the lower limit of the K2O content is preferably 0% or more, 0.0003% or more, 0.0005% or more, and particularly preferably 0.001% or more.

[0063] As mentioned above, Na2O and K2O have similar effects in the present invention. Therefore, when the total amount of Na2O and K2O is too much, crystallinity becomes too strong, glass is easy to devitrify, and crystallized glass is easy to break. And, easily produce refractive index difference between crystalline phase and residual glass, there is the tendency that crystallized glass is easy to be turbid. So, Na2O+K2O is preferably below 2%, below 1.5%, below 1%, below 0.9%, below 0.7%, lower than 0.7%, below 0.6%, below 0.5%, below 0.4%, below 0.3%, below 0.2%, below 0.17%, more preferably below 0.14%. But, because Na2O and K2O are easy to be mixed in as impurities, therefore if want to remove them completely, then there is the tendency that the cost of raw material batch becomes high. In order to suppress the increase in the cost of the raw material batch, the lower limit of Na2O+K2O is preferably greater than 0%, 0.0006% or more, 0.001% or more, and particularly preferably 0.002% or more.

[0064] Na2O, K2O, MgO are the components that reduce the viscosity of glass, improve the fusibility and formability of glass, but when the content of these components is too much, the non-crosslinked oxygen in the glass matrix increases, so the thermal expansion coefficient of the obtained crystallized glass is easy to become high. Although BaO is also the component that reduces the viscosity of glass, improves the fusibility and formability of glass, but compared with the addition of Na2O, K2O, MgO of the amount of same substances, the effect that the thermal expansion coefficient increases when adding BaO is less. Therefore, in order to improve the fusibility and formability of glass, and reduce the thermal expansion coefficient of the obtained crystallized glass, preferably appropriately control (Na2O+K2O+MgO) / BaO. Specifically, (Na2O+K2O+MgO) / BaO is preferably less than 230, less than 100, less than 30, less than 10, less than 6, less than 1, less than 0.8, less than 0.7, less than 0.3, less than 0.2, less than 0.1, more preferably less than 0.06, preferably more than 0.003, more preferably more than 0.01.

[0065] ZnO is the same as BaO that reduces the viscosity of glass and improves the meltability and formability of glass. And, it is also the composition for regulating the thermal expansion coefficient and the refractive index of crystallized glass. When the content of ZnO is too much, it is easy to separate out the crystal containing Zn, and glass is easy to lose transparency, and crystallized glass is easy to break, and in addition, it is also easy to appear cloudy. In addition, ZnO and Li2O are compared with the raw materials of other components outside, and there is a tendency of high price, so owing to containing ZnO, the cost of raw material batch is easy to become high. For this reason, the content of ZnO is preferably below 10%, below 8%, below 6%, below 4%, below 3%, below 2%, lower than 1.1%, below 1%, below 0.8%, below 0.6%, below 0.4%, below 0.2%, below 0.1%, more preferably below 0.05%.

[0066] 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) is a value that greatly affects the thermal expansion characteristics of crystallized glass. When this value is too low, the thermal expansion coefficient of the obtained crystallized glass becomes too high, and there is a tendency that it is difficult to obtain the desired thermal shock resistance. Therefore, the above value is preferably above -1.5%, above 0%, above 5%, above 6%, above 7%, above 8%, above 9%, above 10%, above 11%, above 12%, above 13%, above 14%, above 15%, above 16%, above 17%, and more preferably above 18%. On the other hand, when this value is too high, the cost of the raw material batch becomes high, and in addition, the viscosity of the glass melt also becomes high, and there is a tendency for productivity to deteriorate. Therefore, the above value is preferably less than 30%, less than 29%, less than 28%, less than 27%, less than 26%, less than 25%, less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, and more preferably less than 19%.

[0067] Li2O, Na2O and K2O are components that improve the meltability and formability of glass, but when the content of these components is too high, the low-temperature viscosity will drop excessively, and the glass may flow excessively during crystallization. In addition, Li2O, Na2O, and K2O are components that deteriorate the weather resistance, water resistance, and chemical resistance of glass before crystallization. When the glass before crystallization deteriorates due to moisture, etc., it is possible that the desired crystallization behavior cannot be obtained, and thus the desired performance cannot be obtained. ZrO2 is a component that acts as a nucleating agent, which has the effect of preferentially crystallizing at the initial stage of crystallization and inhibiting the flow of residual glass. In addition, ZrO2 has the effect of effectively filling the voids of the glass network based on the SiO2 skeleton, preventing protons, various chemical components, etc. from diffusing in the glass network, and improving the weather resistance, water resistance, and chemical resistance of the glass before crystallization. On the other hand, when the content of ZrO2 is too much, it is easy to precipitate coarse ZrO2 crystals, the glass is easy to lose transparency, and the crystallized glass is easy to break. Therefore, in order not only to improve the melting property and molding of glass, but also to obtain the crystallized glass of desired shape and performance, it is preferred to appropriately control (Li2O+Na2O+K2O) / ZrO2. Specific preferred (Li2O+Na2O+K2O) / ZrO2 is below 2.5, below 2, below 1.9, below 1.8, below 1.7, below 1.65, below 1.63, below 1.6, particularly below 1.58, and preferably above 0.5, above 0.8, above 1, above 1.2, above 1.4.

[0068] Fe o is the composition of tempered glass coloring, particularly by with TiO , SnO interaction significantly strengthens the composition of coloring.Therefore, in order to suppress the coloring of crystallized glass, Fe o content is preferably below 20000ppm, below 10000ppm, lower than 5000ppm, lower than 3000ppm, below 2000ppm, below 1000ppm, lower than 900ppm, below 700ppm, below 500ppm, below 300ppm, below 200ppm, below 100ppm, below 95ppm, below 85ppm, more preferably below 80ppm.But, due to Fe o easily sneak into as impurity, therefore if want by Fe o completely remove, then the cost of raw material batch material easily becomes high, in order to suppress the increase of the cost of raw material batch material, Fe o the lower limit of content is preferably more than 0.001ppm, more than 0.01ppm, more than 0.1ppm, more than 1ppm, more than 10ppm, more than 30ppm, more preferably more than 40ppm.

[0069] As2O3 and Sb2O3 are highly toxic and may pollute the environment during the glass manufacturing process and waste glass treatment. Therefore, these components are preferably less than 2%, less than 1%, less than 0.7%, less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, less than 0.1%, and more preferably substantially free of them (specifically, less than 0.1% by mass). In addition, As2O3 and Sb2O3 may be contained within a range where the impact on the environment during the glass manufacturing process and waste glass treatment can be ignored, and these components can act as clarifiers, nucleating agents, etc.

[0070] PbO is highly toxic and may pollute the environment during the glass manufacturing process or waste glass treatment. Therefore, each of these components is preferably less than 2%, less than 1%, less than 0.7%, less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, less than 0.1%, and more preferably substantially free of (specifically, less than 0.1% by mass). In addition, PbO may be contained within a range in which the impact on the environment during the glass manufacturing process and waste glass treatment can be ignored, and in this case, it can function as a colorant and an additive for reducing viscosity.

[0071] SrO is a component that reduces the viscosity of glass and improves the meltability and formability of glass. In addition, it is also a component for adjusting the thermal expansion coefficient and refractive index of crystallized glass. When the content of SrO is too much, glass becomes easy to lose transparency and crystallized glass becomes easy to break. In addition, due to the high price of SrO, when added in large quantities, the cost of raw materials tends to become high. Therefore, the content of SrO is not particularly limited, preferably 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, 0.5% or less, more preferably 0.1% or less. However, since SrO is easily mixed in as an impurity, if SrO is to be completely removed, the cost of the raw material batch is easy to become high. In order to suppress the increase in the cost of the raw material batch, the lower limit of the content of SrO is preferably 0.0001% or more, 0.0003% or more, more preferably 0.0005% or more.

[0072] SnO2 is a component that acts as a clarifier. In addition, it is also a component used to efficiently precipitate crystals in the crystallization process. When the content of SnO2 is too little, the glass is difficult to clarify and the productivity is easily reduced. Therefore, the content of SnO2 is preferably more than 0%, more than 0.01%, more than 0.1%, more than 0.15%, and more preferably more than 0.2%. On the other hand, when the content of SnO2 is too much, there is a tendency that the coloring of the crystallized glass becomes stronger or white turbidity occurs. In addition, when the glass is melted, the evaporation amount of SnO2 increases, and the evaporated material of SnO2 is dispersed, which tends to pollute the environment easily. Therefore, the content of SnO2 is preferably less than 3%, less than 2%, and more preferably less than 1.5%.

[0073] V2O5 is the composition that just can influence the color of crystallized glass in trace amount.At V2O5 content when too much, be difficult to obtain the LAS crystallized glass with excellent transparency.Therefore, V2O5 content is preferably below 10000ppm, below 5000ppm, below 1000ppm, below 100ppm, more preferably below 50ppm.But, because V2O5 can be mixed into as the impurity in the raw material, therefore if want to be removed completely, then raw material cost easily becomes high.Therefore, V2O5 content is preferably more than 0ppm, more than 0.001ppm, more than 0.01ppm, more than 0.1ppm, more preferably more than 1ppm.

[0074] Pt is a component that can be mixed into the glass in the state of ions, colloids, metals, etc., and exhibits yellow to brown coloring. In addition, this tendency becomes significant after crystallization. Therefore, the content of Pt is preferably less than 7ppm, less than 6ppm, less than 5ppm, less than 4ppm, less than 3ppm, less than 2ppm, and more preferably less than 1ppm. Although Pt should be avoided as much as possible, in the case of using common melting equipment, in order to obtain homogeneous glass, it is sometimes necessary to use Pt parts. Therefore, if Pt is completely removed, there is a tendency to increase manufacturing costs. In the case of not causing adverse effects on coloring, in order to suppress the increase in manufacturing costs, the lower limit of the content of Pt is preferably more than 0.0001ppm, more than 0.001ppm, more than 0.01ppm, more than 0.02ppm, more than 0.03ppm, more than 0.04ppm, more than 0.05ppm, more than 0.06ppm, and more preferably more than 0.07ppm. In addition, in the case where coloring is acceptable, Pt can also be used as a nucleating agent to promote the precipitation of the main crystal in the same manner as ZrO2 and TiO2. At this time, Pt can be used as a nucleating agent alone or in combination with other components. In addition, when Pt is used as a nucleating agent, there is no special requirement for the form (colloid, metal crystal, etc.).

[0075] Rh is a component that can be mixed into the glass in the form of ions, colloids, metals, etc., and, like Pt, has a tendency to show yellow to brown coloring. For this reason, the content of Rh is preferably less than 7ppm, less than 6ppm, less than 5ppm, less than 4ppm, less than 3ppm, less than 2ppm, less than 1ppm, less than 0.9ppm, less than 0.8ppm, less than 0.7ppm, less than 0.6ppm, less than 0.5ppm, less than 0.4ppm, and more preferably less than 0.3ppm. Although Rh should be avoided as much as possible, when using conventional melting equipment, in order to obtain homogeneous glass, it is sometimes necessary to use Rh parts. Therefore, if you want to completely remove Rh, there is a tendency for increased manufacturing costs. In the case where coloring is not adversely affected, in order to suppress the increase of manufacturing cost, the lower limit of the content of Rh is preferably more than 0.0001ppm, more than 0.001ppm, more than 0.01ppm, more than 0.02ppm, more than 0.03ppm, more than 0.04ppm, more than 0.05ppm, more than 0.06ppm, particularly more preferably more than 0.07ppm. In addition, when being able to accept coloring, Rh can also be used as nucleating agent with ZrO2, TiO2. At this time, Pt can be used as nucleating agent alone, and can also be used as nucleating agent with other components. In addition, when Rh is used as the nucleating agent that promotes the precipitation of main crystallization, form does not have special requirements (colloid, metal crystallization, etc.).

[0076] In addition, Pt+Rh (the total amount of the content of Pt and the content of Rh) is preferably below 7ppm, below 3ppm, below 1ppm, below 0.9ppm, below 0.8ppm, below 0.7ppm, below 0.6ppm, below 0.5ppm, below 0.4ppm, more preferably below 0.3ppm. It should be noted that, although Pt and Rh should be avoided as much as possible, when using common melting equipment, in order to obtain homogeneous glass, it is sometimes necessary to use Pt and Rh parts. Therefore, if Pt and Rh are to be completely removed, there is a tendency for increased manufacturing cost. In the case of not causing adverse effects on coloring, in order to suppress the increase of manufacturing cost, the lower limit of Pt+Rh is preferably more than 0.0001ppm, more than 0.001ppm, more than 0.01ppm, more than 0.02ppm, more than 0.03ppm, more than 0.04ppm, more than 0.05ppm, more than 0.06ppm, more preferably more than 0.07ppm.

[0077] MoO3 is the element that just can influence the color of crystallization and sintered glass in trace amount.It should be noted that, can think in the case of LAS sintered glass, have the effect of suppressing the precipitation as the β-spodumene solid solution of secondary crystallization under certain condition.Therefore, when suppressing β-spodumene solid solution to separate out, MoO3 content is preferably greater than 0ppm, more than 0.1ppm, more than 0.2ppm, more preferably more than 0.3ppm.On the other hand, when adding excessive, sintered glass is colored, and sometimes impairs design.Therefore, from the viewpoint of suppressing sintered glass to be colored, be preferably below 100ppm, below 80ppm, below 60ppm, below 40ppm, more preferably below 20ppm.

[0078] P6O 11 It is a component that affects the absorption and thermal expansion coefficient in the infrared region in LAS crystallized glass. 11 , which can adjust the transmittance of wavelengths around 1300 to 2300 nm, can be used as glass for adjusting the amount of light in optical sensors, etc. In addition, when glasses with similar compositions are compared, Pr6O 11 The more the amount of Pr6O is added, the lower the thermal expansion coefficient of the crystallized glass at 30-380°C. 11The content of Pr6O is preferably 0 ppm or more, 0.1 ppm or more, 0.5 ppm or more, 1 ppm or more, 10 ppm or more, or 30 ppm or more. On the other hand, when excessively added, the resulting crystalline glass and crystallized glass will be strongly colored, sometimes impairing the design. In particular, when the light absorption becomes too large in the infrared region, in the case of products equipped with optical temperature sensors, etc., light is difficult to transmit in a specific wavelength region, which may cause malfunction. Therefore, Pr6O 11 The content is preferably 2000 ppm or less, 1000 ppm or less, 500 ppm or less, 200 ppm or less, 100 ppm or less, and more preferably 50 ppm or less.

[0079] Sm2O3 is the element that is easily mixed into as impurity, if mixed into on a small amount, in LAS system crystallized glass of the present invention, there is the tendency that is difficult to change its characteristic.If want by Sm2O3 completely remove, then the cost of raw material batch material easily becomes high, therefore consider from the viewpoint of reducing the cost of raw material batch material, Sm2O3 content is preferably more than 0ppm, more than 0.1ppm, more than 0.5ppm, more than 1ppm, more than 10ppm, more than 30ppm.On the other hand, when excessively adding, glass and crystallized glass can be strongly colored, sometimes impair designability.Therefore, Sm2O3 content is preferably less than 2000ppm, less than 1000ppm, less than 500ppm, less than 200ppm, less than 100ppm, more preferably less than 50ppm.

[0080] β-OH value has a great influence on the low temperature viscosity and crystallization of glass. β-OH value is preferably more than 0.01 / mm, more than 0.02 / mm, more than 0.04 / mm, more than 0.06 / mm, more preferably more than 0.08 / mm. If β-OH value is within the above range, low temperature viscosity will be reduced, and there is a tendency for crystallization rate to increase, so manufacturing efficiency can be improved. On the other hand, when β-OH value is too high, bubbles are easily generated at the interface with the metal parts for glass melting, and there is a tendency for the quality of glass products to decrease. In addition, according to the composition, the crystallization rate will become too large, and other crystal seeds with little precipitation or precipitation amount will be separated out and grow. As a result, it is possible that the light scattering in the crystallized glass increases, and the crystallized glass is easy to be turbid. Therefore, β-OH value is preferably less than 2 / mm, less than 1.5 / mm, less than 1 / mm, less than 0.8 / mm, less than 0.7 / mm, less than 0.6 / mm, more preferably less than 0.5 / mm. Since the β-OH value varies depending on the raw materials used, the melting atmosphere, the melting temperature, the melting time, etc., the β-OH value can be adjusted by changing these conditions as needed. For example, the β-OH value can be increased by increasing the amount of hydroxide in the raw materials, melting by heating with a burner, or increasing the melting temperature. In addition, the β-OH value can be increased by extending the melting time in a sealed environment and shortening the melting time in an unsealed environment.

[0081] In the crystallized glass of the present invention, as long as it does not have a negative impact on thermal properties and transparency, in addition to the above-mentioned components, trace components such as H2, CO2, CO, H2O, He, Ne, Ar, N2, etc., which are less than 0.1%, can also be contained. In addition, although Ag, Au, Pd, Ir, Sc, Ce, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, U, etc. are intentionally added, there is a tendency that the cost of the raw material batch becomes high, but when the glass containing Ag, Au, etc. is subjected to light treatment or heat treatment, an agglomerate of these components will be formed, which can be used as a starting point to promote crystallization. In addition, Pd, etc. have various catalytic effects, and by containing these components, special functions can be given to the crystallized glass. In view of such circumstances, when the purpose is to promote crystallization or impart other functions, the above-mentioned components can be contained in an amount of less than 1%, less than 0.5%, less than 0.3%, or less than 0.1%, respectively. When these purposes are not particularly required, it is preferably less than 500 ppm, less than 300 ppm, or less than 100 ppm, and particularly preferably less than 10 ppm.

[0082] In addition, as long as thermal properties and transparency are not adversely affected, the crystallized glass of the present invention can also contain SO3, MnO, Cl2, Y2O3, La2O3, WO3, HfO2, Ta2O5, Nd2O3, Nb2O5, RfO2, etc. in total. However, the price of the raw material batch of the above-mentioned components is high, and there is a tendency for manufacturing cost to increase, so unless there are special circumstances, it is not necessary to add. Especially the price of HfO2 is high, and sometimes Ta2O5 is a conflict mineral, therefore, the total amount of these components is preferably less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, less than 0.1%, less than 0.05%, less than 0.05%, less than 0.049%, less than 0.048%, less than 0.047%, less than 0.046%, more preferably less than 0.045%.

[0083] The preferred composition range of the LAS-based crystallized glass of the present invention is 55-75% SiO2, 10-35% Al2O3, 0.1-4% Li2O, 0-10% MgO, 2-10% BaO, 0-5% TiO2, 0-5% ZrO2, 0.01-4% P2O5, greater than 0 and less than 0.7% Na2O+K2O, greater than 0 and less than 900 ppm Fe2O3, 0-0.2% CaO, and 0-25% 8Li2O-4(MgO+Na2O+K2O)-(BaO+ZnO).

[0084] Alternatively, it is preferably 55-75% SiO2, 10-35% Al2O3, 0.1-4% Li2O, 0-10% MgO, 1-10% BaO, 0-1.1% ZnO, 0-5% TiO2, 0-5% ZrO2, 0-5% P2O5, Na2O+K2O greater than 0 and less than 0.7%, and 0-25% 8Li2O-4(MgO+Na2O+K2O)-(BaO+ZnO).

[0085] Alternatively, it is preferably 55-75% SiO2, 10-35% Al2O3, 0.1-3.47% Li2O, 0-10% MgO, 2-10% BaO, 0-5% TiO2, 0-5% ZrO2, 0-5% P2O5, and 18-25% 8Li2O-4(MgO+Na2O+K2O)-(BaO+ZnO).

[0086] Alternatively, it is preferably 55-75% SiO2, 15-30% Al2O3, 2.5-3.55% Li2O, 0-10% BaO, 0-1.1% MgO, 0-1.6% CaO, 0.01-2.5% TiO2, 0-2.9% ZrO2, 0-2% P2O5, 30-2000 ppm Fe2O3, 0-1000 ppm V2O5, and 0-30% 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO).

[0087] Alternatively, it preferably contains 55-75% SiO2, 15-30% Al2O3, 2.0-3.49% Li2O, 2.7-10% BaO, 0-4% MgO+CaO, 0.01-5% TiO2, 1.3-5% ZrO2, 30-10000 ppm Fe2O3, and 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) is 10-30%.

[0088] Alternatively, it preferably contains 55-75% SiO2, 15-30% Al2O3, 2.0-3.55% Li2O, 2.6-10% BaO, 0-4% MgO+CaO, 0.01-2.5% TiO2, 0-2.9% ZrO2, 0-2% P2O5, 30-10000 ppm Fe2O3, and 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) is 0-30%.

[0089] Alternatively, it preferably contains 55-68% SiO2, 15-30% Al2O3, 2.0-3.49% Li2O, 0-2.7% BaO, 1.5-5% MgO+CaO, 0.01-3.9% TiO2, 1.4-2.9% ZrO2, 0-2.5% P2O5, 30-10000 ppm Fe2O3, and 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) is 10-30%.

[0090] Alternatively, it preferably contains 55-75% SiO2, 10-35% Al2O3, 0.1-5% Li2O, 0-10% BaO, 0-10% MgO, 0-5% TiO2, 0-5% ZrO2, 0-5% P2O5, 10-500ppm Pr6O 11 , 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) is less than 30%.

[0091] By having the above composition, it is easy to obtain LAS-based crystallized glass which has a low thermal expansion coefficient, excellent transparency, and reduced raw material batch cost.

[0092] The L* value of the total light transmittance of the LAS crystallized glass of the present invention when the preferred thickness is 4 mm is more than 70, more than 75, more than 80, more than 85, more than 90, more than 91, more than 92, more than 92.5, more than 93, more than 93.5, more preferably more than 94. When this value is too low, the desired transmission ability cannot be obtained, which makes the use limited. And, no matter whether it is colored, there is a tendency that the transmitted light looks darker.

[0093] The a* value of the total light transmittance of the LAS crystallized glass of the present invention when the preferred thickness is 4mm is within ±5, within ±4, within ±3, within ±2.5, within ±2, within ±1.5, within ±1, within ±0.8, within ±0.6, more preferably within ±0.5. When this value is too large in the negative direction, there is a tendency to look green, and when this value is too large in the positive direction, there is a tendency to look red.

[0094] The b* value of the total light transmittance of the LAS crystallized glass of the present invention when the preferred thickness is 4mm is within ±20, within ±15, within ±10, within ±7, within ±6.5, within ±6, within ±5.5, within ±5.3, within ±5, within ±4.8, more preferably within ±4.5. When this value is too large in the negative direction, there is a tendency to look blue, and when this value is too large in the positive direction, there is a tendency to look yellow.

[0095] The LAS crystallized glass of the present invention preferably has a diffuse transmittance L* value of 20 or less, 15 or less, 10 or less, 8 or less, 6 or less, 5 or less, or 4 or less when the thickness is 4 mm, and more preferably 3 or less. When the absolute value of this value is too large, the crystallized glass tends to appear cloudy.

[0096] The a* value of the diffuse transmittance of the LAS crystallized glass of the present invention when the preferred thickness is 4mm is within ±5, within ±4, within ±3, within ±2.5, within ±2, within ±1.5, within ±1, within ±0.8, within ±0.6, more preferably within ±0.5. When this value is too large in the negative direction, there is a tendency to look green, and when this value is too large in the positive direction, there is a tendency to look red.

[0097] The b* value of the diffuse transmittance of the LAS crystallized glass of the present invention when the preferred thickness is 4mm is within ±20, within ±15, within ±10, within ±5, within ±4, within ±3, within ±2.5, within ±2, more preferably within ±1.5. When this value is too large in the negative direction, there is a tendency to look blue, and when this value is too large in the positive direction, there is a tendency to look yellow.

[0098] LAS system crystallized glass of the present invention preferably precipitates out β-quartz solid solution as main crystal. If β-quartz solid solution is precipitated out as main crystal, then because crystal grain size is easy to become smaller, crystallized glass is easy to transmit visible light, and transparency is easy to become higher. And, it is easy to make the thermal expansion coefficient of glass close to zero. It should be noted that LAS system crystallized glass of the present invention is heat-treated at a temperature higher than the crystallization condition that β-quartz solid solution is precipitated out, thereby β-spodumene solid solution is precipitated out. The crystal grain size of β-spodumene solid solution is easy to be larger than β-quartz solid solution, and there is a tendency that turbidity usually occurs when crystallized glass is formed, but by appropriately adjusting glass composition and firing conditions, the refractive index difference between the crystalline phase containing β-spodumene solid solution and the residual glass phase is reduced, and in this case, turbidity does not occur in crystallized glass easily. In LAS system crystallized glass of the present invention, as long as there is no adverse effect on coloring, etc., crystallization of β-spodumene solid solution etc. may also be included.

[0099] The LAS crystallized glass of the present invention preferably has an absolute value of a thermal expansion coefficient of 20×10 ﹣7 / ℃ below, 15×10 ﹣7 / ℃ below, 10×10 ﹣7 / ℃ below, 5×10 ﹣7 / ℃ below, 4×10 ﹣7 / ℃ below, 3×10 ﹣7 / ℃ or less, 2×10 ﹣7 / ℃ below, 1.5×10 ﹣7 / ℃ below, 1×10 ﹣7 / ℃ below.

[0100] The LAS crystallized glass of the present invention preferably has an absolute value of a thermal expansion coefficient of 20×10 ﹣7 / ℃ below, 15×10 ﹣7 / ℃ below, 10×10 ﹣7 / ℃ below, 5×10 ﹣7 / ℃ below, 4×10 ﹣7 / ℃ below, 3×10 ﹣7 / ℃ or less, 2×10 ﹣7 / ℃ below, 1.5×10 ﹣7 / ℃ below, 1×10 ﹣7 / ℃ below.

[0101] When the absolute value of the thermal expansion coefficient is too high, the thermal shock resistance is low and it is difficult to use at high temperatures. In addition, it is difficult to apply to applications that require positional stability. In particular, when it is envisioned to be used as a cooking top plate, in order to avoid damage caused by heat or strain, it is preferred that the absolute value of the thermal expansion coefficient is low. Although there is no particular upper limit on the absolute value of the thermal expansion coefficient, in reality, it is 50×10 ﹣7 / ℃.

[0102] The LAS crystallized glass of the present invention preferably has a density of 2.40 to 2.80 g / cm 3 2.42~2.78g / cm 3 2.44~2.76g / cm 3 2.46~2.74g / cm 3 , particularly preferably 2.47 to 2.73 g / cm 3 . When the density of the crystallized glass is too small, there is a risk that the air permeability of the crystallized glass will deteriorate. On the other hand, when the density of the crystallized glass is too large, the weight per unit area increases, making it difficult to handle. In addition, the density of the crystallized glass is an indicator for determining whether the glass is fully crystallized. Specifically, if it is the same glass, the greater the density (the greater the density difference between the glass before crystallization and the crystallized glass), the more advanced the crystallization.

[0103] The LAS-based crystallized glass of the present invention preferably has a glass transition temperature (temperature at which the slope of the thermal expansion curve of the glass changes) of 690° C. or higher, 700° C. or higher, 710° C. or higher, 720° C. or higher, 730° C. or higher, and more preferably 735° C. or higher. When the glass transition temperature is too low, the glass is too fluid due to heating and is difficult to be molded into a desired shape.

[0104] The LAS-based crystallized glass of the present invention preferably has a yield temperature (a temperature at which the slope of the thermal expansion curve of the glass changes at a temperature above the glass transition temperature) of 750° C. or higher, 760° C. or higher, 770° C. or higher, or 780° C. or higher, and more preferably 790° C. or higher. When the yield temperature is too low, the glass becomes too fluid due to heating and is difficult to be molded into a desired shape.

[0105] The LAS-based crystallized glass of the present invention preferably has a viscosity of about 10 4dPa·s is 1400°C or less, 1390°C or less, 1380°C or less, 1375°C or less, 1370°C or less, 1365°C or less, and more preferably 1360°C or less. When the temperature is too high, the melting property of the glass decreases, and it is difficult to clarify, so the productivity is likely to decrease. In addition, since there is a tendency to easily apply a load to the molded parts, the productivity is likely to decrease.

[0106] The LAS-based crystallized glass of the present invention preferably has a viscosity equivalent to about 10 3.5 dPa·s is 1500°C or less, 1490°C or less, 1480°C or less, 1470°C or less, 1460°C or less, 1450°C or less, and more preferably 1445°C or less. When the temperature is too high, the melting property of the glass decreases, and it is difficult to clarify, so the productivity tends to decrease. In addition, since there is a tendency to easily apply a load to the molded parts, the productivity tends to decrease.

[0107] The LAS-based crystallized glass of the present invention preferably has a viscosity equivalent to about 10 3 dPa·s is 1600°C or less, 1590°C or less, 1580°C or less, 1570°C or less, 1560°C or less, 1550°C or less, 1545°C or less, and more preferably 1540°C or less. When the temperature is too high, the melting property of the glass decreases, and it is difficult to clarify, so the productivity tends to decrease. In addition, since there is a tendency to easily apply a load to the molded parts, the productivity tends to decrease.

[0108] The LAS-based crystallized glass of the present invention preferably has a viscosity equivalent to about 10 2.5 dPa·s is 1700° C. or less, 1690° C. or less, 1680° C. or less, 1670° C. or less, 1660° C. or less, 1655° C. or less, and more preferably 1650° C. or less. If the temperature is too high, the meltability of the glass decreases and clarification becomes difficult, so productivity tends to decrease.

[0109] The LAS-based crystallized glass of the present invention preferably has a liquidus temperature (T L) is 1540°C or less, 1535°C or less, 1530°C or less, 1525°C or less, 1520°C or less, 1515°C or less, 1510°C or less, 1505°C or less, 1500°C or less, 1495°C or less, 1490°C or less, 1485°C or less, 1480°C or less, 1475°C or less, 1470°C or less, 1465°C or less, 1460°C or less, 1455°C or less, 1450°C or less, 1445°C or less, 1440°C or less, 1435°C or less, 1430°C or less, 1425°C or less, 1420°C or less, 1415°C or less, and particularly preferably 1410°C or less. When the liquidus temperature is too high, devitrification is likely to occur during production. On the other hand, if it is below 1480°C, it is easy to manufacture by a rolling method or the like; if it is below 1450°C, it is easy to manufacture by a casting method or the like; and if it is below 1410°C, it is easy to manufacture by a fusion method or the like.

[0110] The preferred liquidus viscosity (logarithm value logη of viscosity corresponding to liquidus temperature) of LAS system crystallized glass of the present invention is 2.70 or more, 2.75 or more, 2.80 or more, 2.85 or more, 2.90 or more, 2.95 or more, 3.00 or more, 3.05 or more, 3.10 or more, 3.15 or more, 3.20 or more, 3.25 or more, 3.30 or more, 3.35 or more, 3.40 or more, 3.45 or more, 3.50 or more, 3.55 or more, 3.60 or more, 3.65 or more, particularly preferably 3.70 or more. When liquidus temperature is too low, it is easy to devitrify during manufacture. On the other hand, if more than 3.40, it is easy to manufacture by rolling method etc.; if more than 3.50, it is easy to manufacture by casting method etc.; if more than 3.70, it is easy to manufacture by melting method etc.

[0111] LAS system crystallized glass of the present invention can also implement the treatments such as chemical strengthening.The conditions of chemical strengthening treatment consider the volume fraction of glass composition, each phase, the kind of molten salt, etc., and appropriately select the treatment time and treatment temperature.For example, it is possible to select to include more Na2O glass compositions that can be included in the residual glass phase, so that it is easy to carry out chemical strengthening treatment.In addition, molten salt can contain monovalent cations such as Li, Na, K or divalent cations such as Mg, Ba, Zn, Ca, Sr separately, and can also contain multiple.And, not only can select common one-step strengthening, it is also possible to select multi-step chemical strengthening.It should be noted that, as molten salt, nitrate (potassium nitrate, sodium nitrate, lithium nitrate, etc.), carbonate (potassium carbonate, sodium carbonate, lithium carbonate, etc.), sulfate (potassium sulfate, sodium sulfate, lithium sulfate, etc.), chloride salt (potassium chloride, sodium chloride, lithium chloride, etc.) or the combination of these salts can be used.Wherein, as molten salt, it is preferred to use nitrates with lower melting points, etc., particularly preferably sodium nitrate. The ion exchange temperature is preferably 330 to 550° C., 350 to 500° C., particularly preferably 390 to 450° C., and the ion exchange time is preferably 30 minutes to 12 hours, 45 minutes to 10 hours. It should be noted that the above strengthening conditions can also be arbitrarily changed according to the required use and strength, and the appropriate conditions are not necessarily limited to the above conditions.

[0112] Next, the method for producing the crystallized glass of the present invention will be described.

[0113] First, a raw material batch prepared in a manner to form a glass of the above composition is put into a glass melting furnace, melted at 1200-1800° C., and then formed. When melting the glass, any one of the following methods, or a combination of two or more methods, can be used: a flame melting method using a burner, an electric melting method using electric heating, a melting method using laser irradiation, a melting method using plasma, a liquid phase synthesis method, and a gas phase synthesis method.

[0114] The molding method is preferably selected from any one of the molding methods such as overflow method, floating method, downdraw method, flow hole downdraw method, re-draw method, containerless method, blowing method, pressing method, roller pressing method, bushing method, tube drawing method, etc., or a combination of two or more methods. In addition, the molded glass can also be reheated at a temperature above the glass transition point. In this way, glass with good surface quality can be manufactured.

[0115] Then the obtained crystallizable glass (glass that can be crystallized before crystallization) is heat treated to crystallize it. As crystallization conditions, firstly, nucleation is carried out at 700-950°C (preferably 750-900°C) for 0.1-100 hours (preferably 1-60 hours), and then crystal growth is carried out at a temperature of 800-1050°C (preferably 800-1000°C) for 0.1-50 hours (preferably 0.2-10 hours). In this way, transparent LAS-based crystallized glass with β-quartz solid solution crystallization as main crystal can be obtained. It should be noted that heat treatment can be carried out only at a certain specific temperature, or it can be maintained at a temperature above two levels, and heat treatment is carried out in stages, and it can also be heated under the state of applying a temperature gradient.

[0116] In addition, crystallization can be promoted by applying and irradiating sound waves or electromagnetic waves. Moreover, the cooling rate of the crystallized glass at high temperature can be carried out under a certain temperature gradient, or under a temperature gradient of more than two levels. In the case of fully obtaining thermal shock resistance, it is desired to control the cooling rate to fully relax the structure of the residual glass phase. The average cooling rate from 800°C to 25°C is preferably 3000°C / min, 1000°C / min or less, 500°C / min or less, 400°C / min or less, 300°C / min or less, 200°C / min or less, 100°C / min or less, 50°C / min or less, 25°C / min or less, 10°C / min or less, and particularly preferably 5°C / min or less. In addition, when long-term dimensional stability is desired, it is further preferred to be less than 2.5°C / min, less than 1°C / min, less than 0.5°C / min, less than 0.1°C / min, less than 0.05°C / min, less than 0.01°C / min, less than 0.005°C / min, less than 0.001°C / min, less than 0.0005°C / min, and particularly preferably less than 0.0001°C / min. Except for the case where physical strengthening treatment is performed by air cooling, water cooling, etc., it is desired that the cooling rate of the surface of the crystallized glass is close to the cooling rate of the part of the wall thickness farthest from the surface of the crystallized glass. The value obtained by dividing the cooling rate of the part of the wall thickness farthest from the surface of the crystallized glass by the cooling rate of the surface of the crystallized glass is preferably 0.0001-1, 0.001-1, 0.01-1, 0.1-1, 0.5-1, 0.8-1, 0.9-1, and particularly preferably 1. Since it is close to 1, residual deformation is not easy to occur at all positions of the crystallized glass sample, and long-term dimensional stability is easy to obtain. It should be noted that the cooling rate of the surface can be estimated by contact temperature measurement or radiation thermometer, and the internal temperature can be estimated based on the numerical data, the specific heat of the crystallized glass, the cooling medium, the thermal conductivity, etc. by placing the crystallized glass in a high temperature state in a cooling medium and measuring the heat and heat change rate of the cooling medium.

[0117] Example

[0118] Hereinafter, the present invention will be described based on examples, but the present invention is not limited to the following examples. Tables 1 to 44 show examples (sample Nos. 1 to 31) of the present invention.

[0119] [Table 1]

[0120]

[0121] [Table 2]

[0122]

[0123] [Table 3]

[0124]

[0125] [Table 4]

[0126]

[0127] [Table 5]

[0128]

[0129] [Table 6]

[0130]

[0131] [Table 7]

[0132]

[0133] [Table 8]

[0134]

[0135] [Table 9]

[0136]

[0137] [Table 10]

[0138]

[0139] [Table 11]

[0140]

[0141] [Table 12]

[0142]

[0143] [Table 13]

[0144]

[0145] [Table 14]

[0146]

[0147] [Table 15]

[0148]

[0149] [Table 16]

[0150]

[0151] [Table 17]

[0152]

[0153] [Table 18]

[0154]

[0155] [Table 19]

[0156]

[0157] [Table 20]

[0158]

[0159] [Table 21]

[0160]

[0161] [Table 22]

[0162]

[0163] [Table 23]

[0164]

[0165] [Table 24]

[0166]

[0167] [Table 25]

[0168]

[0169] [Table 26]

[0170]

[0171] [Table 27]

[0172]

[0173] [Table 28]

[0174]

[0175] [Table 29]

[0176]

[0177] [Table 30]

[0178]

[0179] [Table 31]

[0180]

[0181] [Table 32]

[0182]

[0183] [Table 33]

[0184]

[0185] [Table 34]

[0186]

[0187] [Table 35]

[0188]

[0189] [Table 36]

[0190]

[0191] [Table 37]

[0192]

[0193] [Table 38]

[0194]

[0195] [Table 39]

[0196]

[0197] [Table 40]

[0198]

[0199] [Table 41]

[0200]

[0201] [Table 42]

[0202]

[0203] [Table 43]

[0204]

[0205] [Table 44]

[0206]

[0207] First, each raw material is mixed in the form of oxides, hydroxides, carbonates, nitrates, etc. in such a manner as to form a glass having the composition described in each table, thereby obtaining a raw material batch. The obtained raw material batch is melted at a temperature of 1500-1700°C to form an ingot shape having a thickness of about 15 mm, and heat-treated at 700°C for 60 minutes using an annealing furnace, and the annealing furnace is cooled to room temperature at 100°C / h, thereby obtaining a glass sample. The composition described in the table is the analysis value of the glass actually produced. The melting is carried out by the electric melting method widely used in the development of glass raw materials.

[0208] The Pt and Rh contents of the samples were analyzed using an ICP-MS (Inductively Coupled Plasma Mass Spectrometry) device (Agilent 8800 manufactured by Agilent Technologies). First, the prepared glass sample was crushed and moistened with pure water, and then perchloric acid, nitric acid, sulfuric acid, hydrofluoric acid, etc. were added to melt it. Then, the Pt and Rh contents of the sample were measured by ICP-MS. Based on the calibration curve prepared using the Pt and Rh solutions with known concentrations prepared in advance, the Pt and Rh contents of each measured sample were obtained. The measurement mode was set to Pt: He gas / HMI (low mode) and Rh: HEHe gas / HMI (medium mode), and the mass number was set to Pt: 198 and Rh: 103. It should be noted that the Li2O content of the prepared sample was analyzed using an atomic absorption spectrometer (ContrAA600 manufactured by Analytik Jena). The melting method of the glass sample and the use of the calibration curve are basically the same as those for the Pt and Rh analysis. In addition, other components were measured by ICP-MS or atomic absorption analysis in the same manner as Pt, Rh, and Li2O, or a glass sample with a known concentration that was previously studied using an ICP-MS or atomic absorption analysis device was used as a calibration curve sample, and a calibration curve was prepared using an XRF (fluorescent X-ray) analysis device (ZSX Primus IV manufactured by RIGAKU). Based on the calibration curve, the actual content of each component was obtained from the XRF analysis value of the measured sample. When performing XRF analysis, the tube voltage, tube current, exposure time, etc. were adjusted at any time according to the analyzed component.

[0209] The crystalline glasses listed in the tables were subjected to a nucleation treatment at 700-950°C for 0.75-10 hours, followed by a heat treatment at 800-1050°C for 0.25-3 hours for crystal growth, thereby obtaining LAS-based crystallized glasses with β-quartz solid solution crystals as the main crystals. The β-OH value, precipitated crystals, crystallinity, grain size, density, thermal expansion coefficient, total light transmittance, and diffuse transmittance of the obtained LAS-based crystallized glasses were measured and evaluated. In addition, the density and thermal expansion coefficient of the crystalline glasses before crystallization were measured and evaluated in the same manner as for the crystallized glasses, and the glass transition temperature (Tg), yield temperature (Tf), temperature at high temperature viscosity (10 4 dPa·s, 10 3.5 dPa·s, 10 3 dPa·s, 10 2.5 dPa·s), liquidus temperature (T L ), liquidus viscosity (logη, η represents the glass viscosity at the liquidus temperature (dPa·s)), and the initial phase were also measured and evaluated.

[0210] The β-OH value was determined by measuring the transmittance of the glass using FT-IR Frontier (manufactured by Perkin Elmer) and using the following formula. The scanning speed was 100 μm / min and the sampling interval was 1 cm. ﹣1 The number of scans was set to 5 per measurement.

[0211] β-OH=(1 / X)log10(T1 / T2)

[0212] X: Glass thickness (mm)

[0213] T1: Reference wavelength 3846cm ﹣1 Transmittance at (%)

[0214] T2: Hydroxyl absorption wavelength 3600cm ﹣1 Minimum transmittance near (%)

[0215] The precipitated crystals were evaluated using an X-ray diffraction device (Malvern Panalytical desktop X-ray diffraction device Aeris). The measurement range was 5 to 60°, the measurement step was 0.01°, the scanning speed was 1.5° / min, and the main crystal and crystal grain size were evaluated using analysis software. The precipitated crystals identified as the main crystals are shown in the table. In addition, the crystallinity is obtained by the integrated intensity ratio of the amorphous peak and the crystalline peak. Moreover, the average grain size of the main crystal is calculated using the X-ray diffraction peak measured based on the Debeye-Sherrer method.

[0216] The density was evaluated by the Archimedean method.

[0217] The thermal expansion coefficient was evaluated by measuring the average linear thermal expansion coefficient in the temperature ranges of 30 to 380° C. and 30 to 750° C. using a glass sample processed into 20 mm×Φ3.8 mm. A Dilatometer manufactured by NETZSCH was used for the measurement.

[0218] Each transmittance was evaluated by measuring a crystallized glass plate (30 mm square) with both sides optically polished to a wall thickness of 4 mm using a spectrophotometer. The measurement was performed using a spectrophotometer V-670 manufactured by JASCO Corporation. It should be noted that the V-670 is equipped with "ISN-723" as an integrating sphere unit, and the transmittance measured when equipped with the attached barium plate is equivalent to the total light transmittance. In addition, the measurement wavelength range is set to 380 to 780 nm, the scanning speed is set to 200 nm / min, the sampling interval is set to 1 nm, and the bandwidth is set to 5 nm. If necessary, the wavelength range other than the above (200 to 2500 nm) is also measured under the same conditions. However, in the near-infrared region, it is measured with a bandwidth of 20 nm. Baseline correction (100% matching) and dark area measurement (0% matching) were performed before the measurement. When measuring the dark area, the barium sulfate plate attached to ISN-723 was removed. In addition, the diffuse transmittance of crystallized glass was measured using the same device as above, with the barium sulfate plate attached to ISN-723 removed and the measurement sample set. The chromaticity of each transmittance was calculated by calculating the chromaticity of the 2-degree field of view of the D65 light source. The calculation method refers to JIS Z 8781-4.

[0219] The thermal expansion curve of the glass sample in the temperature range of 30 to 750° C. was measured using a Dilatometer manufactured by NETZSCH, and the inflection point was calculated to evaluate the glass transition temperature and yield temperature.

[0220] The temperature at high temperature viscosity was evaluated using the platinum ball pulling method. During the evaluation, the bulk glass sample was broken into appropriate sizes and placed in an alumina crucible with as few bubbles as possible. The alumina crucible was then heated to make the sample a molten state, and the viscosity of the glass at multiple temperatures was measured. The constant of the Vogel-Fulcher formula was calculated and a viscosity curve was prepared to calculate the temperature at each viscosity.

[0221] The liquidus temperature was evaluated by the following method. First, glass powder with a particle size of 300 to 500 μm was filled into a platinum boat of about 120×20×10 mm and placed in an electric furnace, and melted at 1600°C for 30 minutes. Then, the platinum boat was placed in an electric furnace with a linear temperature gradient for 20 hours to precipitate the devitrified material. After the test sample was cooled to room temperature, the devitrified material precipitated at the interface between the platinum boat and the glass was observed, and the temperature of the devitrified material precipitation site was calculated based on the temperature gradient curve of the electric furnace as the liquidus temperature. In addition, the obtained liquidus temperature was interpolated into the high-temperature viscosity curve of the glass, and the viscosity equivalent to the liquidus temperature was taken as the liquidus viscosity.

[0222] The primary phase generated in the crystallized glass of the Examples described in the respective tables was analyzed using X-ray diffraction, composition analysis, and the like (scanning electron microscope manufactured by Hitachi, S3400N Type 2 manufactured by Hitachi, and EMAX ENERGY EX250X manufactured by Horiba).

[0223] It can be clearly seen from the table that the crystallized glasses of Examples No. 1 to 131 have excellent transparency due to their low thermal expansion coefficient, high L* value of total light transmittance, and small a* value and b* value of total light transmittance.

[0224] Figure 1 The scatter diagram is obtained by plotting the thermal expansion coefficient of the crystallized glass of each embodiment of the present invention at 30 to 750°C in correspondence with the 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) value. It can be seen that as the 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) value increases, there is a tendency for the thermal expansion coefficient of the crystallized glass to decrease.

Claims

1. A LAS-based crystallized glass, characterized in that: In terms of mass%, it contains 55-75% SiO2, 10-35% Al2O3, 0.1-5% Li2O, 0-10% BaO, 0-10% MgO, 0-5% TiO2, 0-5% ZrO2, and 0-5% P2O5, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) is less than 30%.

2. The LAS-based crystallized glass according to claim 1, wherein: In terms of mass %, it contains 0.1 to 4% Li2O, 1 to 10% BaO, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) at 0 to 25%.

3. The LAS-based crystallized glass according to claim 2, wherein: In terms of mass %, BaO is contained in an amount of 2 to 10%.

4. The LAS-based crystallized glass according to claim 2 or 3, wherein: In terms of mass %, it contains more than 0 and less than 0.7% of Na2O+K2O.

5. The LAS-based crystallized glass according to claim 4, wherein: In terms of mass %, it contains 0.01 to 4% P2O5.

6. The LAS-based crystallized glass according to claim 5, wherein: In terms of mass %, it contains Fe2O3 in an amount of 0 to less than 900 ppm.

7. The LAS-based crystallized glass according to claim 6, wherein: In terms of mass %, it contains 0 to 0.2% of CaO.

8. The LAS-based crystallized glass according to claim 2 or 3, wherein: In terms of mass %, 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) is between 12% and 25%.

9. The LAS-based crystallized glass according to claim 2 or 3, wherein: It contains virtually no As2O3 and Sb2O3.

10. The LAS-based crystallized glass according to claim 2 or 3, wherein: In terms of mass ratio, Li2O / BaO is below 2.

5.

11. The LAS-based crystallized glass according to claim 2 or 3, wherein: In terms of mass ratio, (Na2O+K2O+MgO) / BaO is less than 6.

12. The LAS-based crystallized glass according to claim 2 or 3, wherein: In terms of mass ratio, (Li2O+Na2O+K2O) / ZrO2 is below 2.

5.

13. The LAS-based crystallized glass according to claim 4, wherein: In terms of mass%, ZnO is contained in an amount of 0 to less than 1.1%.

14. The LAS-based crystallized glass according to claim 2 or 3, wherein: In terms of mass %, it contains 0.1 to 3.47% Li2O and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) at 18 to 25%.

15. The LAS-based crystallized glass according to claim 2 or 3, wherein: In terms of mass%, it contains 0.1 to 2000 ppm of Pr6O 11 .

16. The LAS-based crystallized glass according to claim 2 or 3, wherein: In terms of mass %, it contains 0.1 to 2000 ppm of Sm2O3.

17. A LAS-based crystallized glass, characterized in that: In terms of mass%, it contains 55-75% SiO2, 15-30% Al2O3, 2.5-3.55% Li2O, 0-1.1% MgO, 0-1.6% CaO, 0.01-2.5% TiO2, 0-2.9% ZrO2, 0-2% P2O5, 30-2000ppm Fe2O3, 0-1000ppm V2O5, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) at 0-30%.

18. A LAS-based crystallized glass, characterized in that: In terms of mass%, it contains 55-75% SiO2, 15-30% Al2O3, 2.0-3.49% Li2O, 2.7-10% BaO, 0-4% MgO+CaO, 0.01-5% TiO2, 1.3-5% ZrO2, 30-10000 ppm Fe2O3, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) at 10-30%.

19. A LAS-based crystallized glass, characterized in that: In terms of mass%, it contains 55-75% SiO2, 15-30% Al2O3, 2.0-3.55% Li2O, 2.6-10% BaO, 0-4% MgO+CaO, 0.01-2.5% TiO2, 0-2.9% ZrO2, 0-2% P2O5, 30-10000 ppm Fe2O3, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) at 0-30%.

20. A LAS-based crystallized glass, characterized in that: In terms of mass%, it contains 55-68% SiO2, 15-30% Al2O3, 2.0-3.49% Li2O, 0-2.7% BaO, 1.5-5% MgO+CaO, 0.01-3.9% TiO2, 1.4-2.9% ZrO2, 0-2.5% P2O5, 30-10000 ppm Fe2O3, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) at 10-30%.

21. The LAS-based crystallized glass according to claim 2 or 3, wherein: The total light transmittance L* value is above 90 when the thickness is 4 mm.

22. The LAS-based crystallized glass according to claim 2 or 3, wherein: β-quartz solid solution precipitated as the main crystal.

23. The LAS-based crystallized glass according to claim 2 or 3, wherein: The thermal expansion coefficient at 30-750℃ is -20×10 ﹣7 / ℃~20×10 ﹣7 / ℃.

24. A method for manufacturing LAS-based crystallized glass, which is a method for manufacturing the LAS-based crystallized glass according to claim 2 or 3, the manufacturing method is characterized in that it comprises: A step of melting glass raw materials to obtain molten glass; a step of shaping the molten glass; and a step of heat-treating the glass obtained in the step of shaping the molten glass to crystallize it, The method for shaping the molten glass is at least one selected from overflow method, float method, down-draw method, orifice down-draw method, re-draw method, containerless method, blowing method, pressing method, rolling method, bushing method and tube drawing method.

25. A crystallizable glass, characterized in that: In terms of mass%, it contains 55-75% SiO2, 10-35% Al2O3, 0.1-5% Li2O, 0-10% BaO, 0-10% MgO, 0-5% TiO2, 0-5% ZrO2, and 0-5% P2O5, and satisfies 8Li2O-4(Na2O+K2O+MgO)-(BaO+ZnO) is less than 30%.

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