WO2025254110A1 - Glass, chemically strengthened glass, method for producing glass, and method for producing chemically strengthened glass - Google Patents

Abstract

The present invention relates to a glass comprising, in mole percentage on an oxide basis, 60.0 to 75.0% of SiO2, 2.0 to 20.0% of Al2O3, 20.0 to 30.0% of Li2O, 0.0 to 10.0% of MgO, 0.0 to 10.0% of CaO, 2.00 to 10.00% of ZrO2, and 0.50 to 5.00% of P2O5, substantially free of Y2O3, wherein the value of X represented by X = ([TiO2] + [P2O5]) / [ZrO2] is 0.70 or less. Herein, the brackets [ ] denote the contents of each component within the parentheses in mole percentage on an oxide basis.

Description

Glass, chemically strengthened glass, method for manufacturing glass, and method for manufacturing chemically strengthened glass

The present invention relates to glass, chemically strengthened glass, a method for manufacturing glass, and a method for manufacturing chemically strengthened glass. The present invention also relates to display devices, electronic device products, and solar cell modules that include the above-mentioned glass or chemically strengthened glass.

Chemically strengthened glass materials are sometimes used in electronic devices such as mobile phones, smartphones, and tablet devices, as well as in car navigation systems and other electronic devices installed in vehicles such as automobiles, and in window glass. In particular, in recent years, "glass ceramics" containing microcrystals have been attracting attention as a base glass for obtaining high-strength chemically strengthened glass.

Increasing the crystallization rate of crystallized glass makes it possible to further increase the strength of chemically strengthened glass obtained by using that crystallized glass as a base glass. In order to increase the crystallization rate of crystallized glass, glass compositions containing large amounts of elements such as Li ions, which form the crystals, and Zr, which acts as the crystal nucleus, are being developed.

For example, Patent Document 1 discloses crystallized glass having a composition containing 1.5 to 6 mol % of ZrO ₂ and 12 to 22 mol % of Li ₂ O, with the aim of providing crystallized glass with a high crystal content.

International Publication No. 2021/135992

High-alumina bricks, which are bricks with a _{high Al2O3} content, and high-zirconia bricks, which are bricks with a high _ZrO2 content, are generally used as components of a melting furnace used to melt glass raw materials. Glasses with a high Li and Zr content in the above-mentioned composition are subject to greater corrosion at high temperatures than the high-alumina and high-zirconia bricks. This makes the bricks more susceptible to corrosion during the melting of glass raw materials, shortening the service life of the melting furnace. Furthermore, eroded and liberated brick particles become crystal nuclei, making the resulting glass more susceptible to devitrification defects.

Accordingly, the present invention aims to provide glass with low brick corrosion resistance and a method for manufacturing the same. It also aims to provide chemically strengthened glass using the above glass as a base glass and a method for manufacturing the same. It also aims to provide display devices, electronic device products, and solar cell modules that include the above glass or chemically strengthened glass.

In response to the above-mentioned issues, the inventors have discovered a new glass composition that exhibits excellent brick erosion properties, i.e., low brick erosion.

One aspect of the present invention is a composition comprising, in mole percentage on an oxide basis:
_SiO2 60.0 to 75.0%,
2.0 to 20.0% Al ₂ O ₃ ,
20.0 to 30.0% Li ₂ O,
MgO 0.0 to 10.0%,
CaO 0.0 to 10.0%,
Contains 2.00 to 10.00% _ZrO2 and 0.50 to 5.00% _{P2O5 ;}
Substantially does not contain Y ₂ O ₃ , and
The present invention relates to glass in which the value of X represented by the following formula (1) is 0.70 or less.
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis.

In another aspect of the present invention, the composition of the center portion in the thickness direction is expressed in mole percentage based on oxides as follows:
_SiO2 60.0 to 75.0%,
2.0 to 20.0% Al ₂ O ₃ ,
20.0 to 30.0% Li ₂ O,
MgO 0.0 to 10.0%,
CaO 0.0 to 10.0%,
Contains 2.00 to 10.00% _ZrO2 and 0.50 to 5.00% _{P2O5 ;}
Substantially does not contain Y ₂ O ₃ , and
The present invention relates to a chemically strengthened glass, wherein the value of X represented by the following formula (1) is 0.70 or less.
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis at the center in the thickness direction.

Another aspect of the present invention is a method for producing glass, comprising:
The method comprises heating and melting glass raw materials in a melting furnace,
The melting furnace includes electroformed bricks containing 85 mass% or more of Al ₂ O ₃ expressed as a mass percentage based on oxides,
The glass has, in mole percentage on an oxide basis,
_SiO2 60.0 to 75.0%,
2.0 to 20.0% Al ₂ O ₃ ,
20.0 to 30.0% Li ₂ O,
MgO 0.0 to 10.0%,
CaO 0.0 to 10.0%,
Contains 2.00 to 10.00% _ZrO2 and 0.50 to 5.00% _{P2O5 ;}
Substantially does not contain Y ₂ O ₃ , and
The present invention relates to a method for producing glass, in which the value of X represented by the following formula (1) is 0.70 or less.
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis.

Another aspect of the present invention relates to a method for producing chemically strengthened glass, which includes chemically strengthening the above-mentioned glass.

Another aspect of the present invention relates to a display device having the above-mentioned chemically strengthened glass and a display.

Another aspect of the present invention relates to an electronic device product that has the above-mentioned chemically strengthened glass as part of its constituent parts.

Another aspect of the present invention relates to a solar cell module having the above-mentioned chemically strengthened glass.

The present invention provides glass with a new composition that exhibits low brick corrosion resistance, and a method for producing the same. Furthermore, by chemically strengthening this glass, high-strength chemically strengthened glass can be obtained. The glass or chemically strengthened glass of the present invention can be suitably used in, for example, display devices, electronic device products, and solar cell modules.

The present invention will be described in detail below based on the following embodiments, but the present invention is not limited to the following embodiments and can be modified and implemented as desired without departing from the spirit of the present invention.

In this specification, glass compositions are expressed in mole percentages based on oxides, and mole % is sometimes simply referred to as %. Furthermore, the use of "to" to indicate a numerical range means that the numerical values before and after it are included as the lower and upper limits.

In a glass composition, "substantially free" means that it is not contained except for unavoidable impurities contained in raw materials, etc., i.e., it is not intentionally contained. In this specification, unless otherwise specified, "substantially free" in a glass composition means, for example, that the content in the glass composition is less than 0.05 mol%.

Glass
The glass of this embodiment may be amorphous glass containing no crystalline phase, or may be crystallized glass containing a crystalline phase. The glass of this embodiment is preferably crystallized glass, as described below.

The glass of this embodiment contains, in mole percentages based on oxides, 60.0 to 75.0% _SiO2 , _2.0 to 20.0% _Al2O3 , 20.0 to 30.0% _Li2O , 0.0 to 10.0% MgO, 0.0 to 10.0% CaO, 2.00 to 10.00% _{ZrO2 ,} and 0.50 to 5.00% _P2O5 , _and is substantially free of _Y2O3 .

SiO ₂ is a component that forms the network structure of the glass and is an essential component of the glass of this embodiment. It is also a component that increases chemical durability and is a constituent of lithium silicate crystals and lithium aluminosilicate crystals. In the glass of this embodiment, the SiO ₂ content is 60.0 to 75.0%. From the above viewpoints, the SiO ₂ content is 60.0% or more, preferably 62.0% or more, more preferably 64.0% or more, and even more preferably 66.0% or more. From the viewpoint of sufficiently increasing the stress due to chemical strengthening, the SiO ₂ content is 75.0% or less, preferably 73.0% or less, more preferably 72.0% or less, and even more preferably 70.0% or less.

Al ₂ O ₃ is a component that increases the surface compressive stress due to chemical strengthening and is an essential component of the glass of this embodiment. In the glass of this embodiment, the Al ₂ O ₃ content is 2.0 to 20.0%. From the above-mentioned viewpoints, the Al ₂ O ₃ content is 2.0% or more, preferably 2.4% or more, more preferably 3.0% or more, and even more preferably 4.0% or more. From the viewpoint of reducing the haze value of the glass, the Al ₂ O ₃ content is 20.0% or less, preferably 15.0% or less, more preferably 10.0% or less, and even more preferably 8.0% or less.

Li ₂ O is a component that suppresses the elution of ZrO ₂ contained in bricks and reduces the brick erosion of the glass. Li ₂ O is also a component that forms surface compressive stress through ion exchange, and is also a constituent of lithium silicate crystals, lithium aluminosilicate crystals, and lithium phosphate crystals. In the glass of this embodiment, the Li ₂ O content is 20.0 to 30.0%. From the above viewpoints, the Li ₂ O content is 20.0% or more, preferably 22.0% or more, more preferably 24.0% or more, and even more preferably 26.0% or more. From the viewpoint of maintaining chemical durability, the Li ₂ O content is 30.0% or less, preferably 29.0% or less, more preferably 28.0% or less, and even more preferably 27.0% or less.

Although MgO is not essential, it is a component that suppresses the elution of _ZrO2 contained in bricks and reduces the brick erosion of the glass, and may be contained. MgO is also a component that improves the meltability of the glass. In the glass of this embodiment, the MgO content is 0.0 to 10.0%. From the above-mentioned viewpoints, when the glass of this embodiment contains MgO, the content is preferably 0.5% or more, more preferably 1.5% or more, and even more preferably 2.0% or more. From the viewpoint of suppressing a decrease in the ion exchange rate, the MgO content is 10.0% or less, preferably 7.0% or less, more preferably 5.0% or less, and even more preferably 3.0% or less.

Although CaO is not essential, it may be contained as it is a component that suppresses the elution of _ZrO2 contained in bricks and reduces the brick erosion of the glass. CaO is also a component that improves the meltability of the glass. In the glass of this embodiment, the CaO content is 0.0 to 10.0%. From the above-mentioned viewpoints, when the glass of this embodiment contains CaO, the content is preferably 0.5% or more, more preferably 0.8% or more, and even more preferably 1.0% or more. From the viewpoint of suppressing a decrease in the ion exchange rate, the CaO content is 10.0% or less, preferably 7.0% or less, more preferably 5.0% or less, and even more preferably 3.0% or less.

_ZrO2 is a component that suppresses _the elution of _ZrO2 and _Al2O3 contained in bricks and reduces the brick corrosion of the glass, and is an essential component of the glass of this embodiment. _ZrO2 is also a component that can form crystal nuclei during the crystallization process to obtain crystallized glass. In the glass of this embodiment, the _ZrO2 content is 2.00 to 10.00%. From the above viewpoints, the _ZrO2 content is 2.00% or more, preferably 2.80% or more, more preferably 3.00% or more, and even more preferably 4.00% or more. From the viewpoint of suppressing devitrification during melting, the _ZrO2 content is 10.00% or less, preferably 8.00% or less, more preferably 7.00% or less, and even more preferably 6.00% or less.

P ₂ O ₅ is a component that suppresses the elution of ZrO ₂ and Al ₂ O ₃ contained in bricks and reduces the brick corrosion of the glass, and is an essential component of the glass of this embodiment. Furthermore, P ₂ O ₅ is a component that promotes phase separation and crystallization of the glass, and is also a constituent of lithium phosphate crystals. In the glass of this embodiment, the P ₂ O ₅ content is 0.50 to 5.00%. From the above viewpoints, the P ₂ O ₅ content is 0.50% or more, preferably 0.70% or more, more preferably 0.80% or more, even more preferably 0.90% or more, particularly preferably more than 0.90%, and most preferably 1.20% or more. From the viewpoint of suppressing excessive phase separation during melting and suppressing a decrease in acid resistance, the content of P ₂ O ₅ is 5.00% or less, preferably 4.00% or less, more preferably 3.00% or less, even more preferably 2.00% or less, particularly preferably 1.60% or less, and most preferably 1.40% or less.

Y ₂ O ₃ promotes the elution of Al ₂ O ₃ contained in bricks. Therefore, from the viewpoint of reducing the brick corrosion of the glass, the glass of this embodiment does not substantially contain Y ₂ O _3. "Substantially not containing Y ₂ O _3" means that the content of Y ₂ O ₃ in the glass composition is less than 0.05%.

Although _TiO2 is not essential, it is a component that can form crystal nuclei during the crystallization process to obtain crystallized glass, and may be contained. Furthermore, _TiO2 is a component that suppresses the elution _{of Al2O3} contained in bricks, particularly reducing the corrosiveness of the glass to high-alumina bricks. In the glass of this embodiment, the _TiO2 content is preferably 0.00 to 0.10%. When the glass of this embodiment contains _TiO2 , the content may be 0.05% or more, or even 0.06% or more, from the above-mentioned viewpoint. Since _TiO2 promotes the elution of _ZrO2 contained in bricks, particularly from the viewpoint of reducing the corrosiveness of the glass to high-zirconia bricks, the _TiO2 content is preferably 0.10% or less, more preferably 0.09% or less, and even more preferably 0.08% or less; the lower the content, the better. It is most preferable that the glass of this embodiment does not substantially contain _TiO2 . Substantially free of _TiO2 means that the content of _TiO2 in the glass composition is less than 0.05%.

In the glass of this embodiment, the value of X represented by the following formula (1) is 0.70 or less.
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis.

If the value of X is 0.70 or less, glass with low brick erosion can be more suitably obtained. The value of X is preferably 0.66 or less, more preferably 0.60 or less, and even more preferably 0.40 or less. There is no particular lower limit to the value of X, but it may be 0.05 or more, may be greater than 0.09, or may be 0.15 or more. The value of X is, for example, 0.05 to 0.70.

In the glass of this embodiment, the total content of _ZrO2 , _P2O5 , _{and TiO2} ([ _ZrO2 ] + [ _P2O5 ] + [ _TiO2 ]) is preferably 3.00% or more. When [ _ZrO2 ] + [ _P2O5 ] + [ _TiO2 ] is _3.00 % or more, _a glass with low brick erosion can be more suitably obtained. The above [ _ZrO2 ] + [ _P2O5 ] + [ _TiO2 ] is preferably 3.00% or more, more preferably 3.30% or more, and is preferably 7.00% or less, more preferably 6.50% or less. [ _{ZrO2 ]} + [ _P2O5 ] + [ _TiO2 ] is _, for example, 3.00 to 7.00%.

Although Na ₂ O is not essential, it is a component that lowers the melting temperature of the glass and improves the meltability of the glass, and may be contained. When the glass of this embodiment contains Na ₂ O, the content is preferably 0.50% or more, more preferably 1.00% or more, even more preferably 2.00% or more, and particularly preferably 2.50% or more, from the viewpoint of improving the meltability of the glass. From the viewpoint of suppressing a decrease in chemical strengthening properties, the content of Na ₂ O is preferably 6.00% or less, more preferably 4.00% or less, even more preferably 3.50% or less, particularly preferably 3.00% or less, and most preferably 2.70% or less.

Although K ₂ O is not essential, it is a component that lowers the melting temperature of the glass and improves the meltability of the glass, and may be contained. When the glass of this embodiment contains K ₂ O, the content is preferably 0.10% or more, more preferably 0.20% or more, even more preferably 0.30% or more, and particularly preferably 0.60% or more, from the viewpoint of improving the meltability of the glass. From the viewpoint of suppressing a decrease in chemical strengthening properties, the content of K ₂ O is preferably 6.00% or less, more preferably 4.00% or less, even more preferably 3.50% or less, particularly preferably 3.00% or less, and most preferably 2.50% or less.

Although _SnO2 is not essential, it has the effect of promoting the formation of crystal nuclei and may be contained. When the glass of this embodiment contains _SnO2 , the content is preferably 0.1% or more, more preferably 0.3% or more, even more preferably 1% or more, and particularly preferably 2% or more. On the other hand, in order to suppress devitrification during melting, the content of _SnO2 is preferably 6% or less, more preferably 5% or less, even more preferably 4% or less, and particularly preferably 3% or less.

Although B ₂ O ₃ is not essential, it is a component that improves the chipping resistance and meltability of glass or chemically strengthened glass, and may be contained. When the glass of this embodiment contains B ₂ O ₃ , the content is preferably 0.5% or more to improve meltability, more preferably 1% or more, and even more preferably 2% or more. On the other hand, the content of B ₂ O ₃ is preferably 5% or less to suppress the occurrence of striae during melting and the deterioration of glass quality. The content of B ₂ O ₃ is more preferably 4% or less, even more preferably 3% or less, and particularly preferably 2% or less.

While not essential, BaO, SrO, and ZnO are components that improve the meltability of glass and may be contained. They also improve the transmittance of the glass-ceramics by increasing the refractive index of the amorphous phase of the glass-ceramics, bringing it closer to the crystalline phase, thereby improving the transmittance and lowering the haze value. When the glass of this embodiment contains at least one of BaO, SrO, and ZnO, the total content ([BaO] + [SrO] + [ZnO]) is preferably 0.3% or more, more preferably 0.5% or more, even more preferably 0.7% or more, and particularly preferably 1% or more. On the other hand, these components may reduce the ion exchange rate. To improve chemical strengthening properties, [BaO] + [SrO] + [ZnO] is preferably 2.5% or less, more preferably 2% or less, even more preferably 1.7% or less, and particularly preferably 1.5% or less.

Although _CeO2 is not essential, it is a component that oxidizes the glass and may suppress coloration, so it may be contained. When the glass of this embodiment contains _CeO2 , the content is preferably 0.03% or more, more preferably 0.05% or more, and even more preferably 0.07% or more. When _CeO2 is used as an oxidizing agent, the content of _CeO2 is preferably 1.5% or less, more preferably 1.0% or less, in order to increase the transparency of the glass.

When the glass is colored for use, a coloring component may be added to the extent that the desired chemical strengthening properties are not impaired. Suitable examples of _the coloring component include _Co3O4 , _MnO2 , _Fe2O3 , _NiO , _CuO , _{Cr2O3 , V2O5} , _Bi2O3 , _{SeO2 , Er2O3 , and Nd2O3} .

The total content of coloring components is preferably 1% or less. If a higher visible light transmittance of the glass is desired, it is preferable that these components are substantially absent.

Furthermore, SO ₃ , chlorides, fluorides, etc. may be appropriately contained as a fining agent during melting of the glass. The glass of this embodiment preferably does not contain As ₂ O _3. When the glass of this embodiment contains Sb ₂ O ₃ , the content is preferably 0.3% or less, more preferably 0.1% or less, and it is most preferable that the glass does not contain Sb ₂ O ₃ .

The glass of this embodiment preferably exhibits an erosion amount of 0.090 mm/day or less of electroformed bricks containing 85 mass % or more of Al ₂ O ₃ expressed as oxide-based mass percentage, as measured by a finger test method under the following conditions.
(Conditions) The glass is heated to a temperature T2 in a crucible, at which the viscosity of the glass becomes 10 ² dPa·s, and then cooled to a temperature T3.5, at which the viscosity of the glass becomes 10 ^3.5 dPa·s. A test piece of electroformed brick is immersed in the resulting glass and held at T3.5 for 48 hours. The glass is then cooled to 20°C or below. The test piece is removed from the crucible along with the surrounding glass, and the test piece is cut on a plane perpendicular to the contact surface between the glass and the test piece, horizontally ground, and mirror-polished. The maximum erosion amount of the test piece is measured for the resulting cross section using a projector.

The electroformed bricks used in the finger test are high-alumina bricks containing 85% by mass or more _{of Al2O3} expressed as a mass percentage based on oxides. The glass of this embodiment exhibits a high-alumina brick erosion rate measured by the finger test of 0.090 mm/day or less, more preferably 0.085 mm/day or less, and even more preferably 0.080 mm/day or less; the lower the better. The erosion rate is an indicator of the glass's resistance to corrosion by high-alumina bricks, and can be adjusted by the glass composition.

The glass of this embodiment preferably exhibits an erosion amount of 0.20 mm/day or less of electroformed bricks containing 80 mass % or more of _ZrO2 , expressed as a mass percentage based on oxides, as measured by a finger test method under the following conditions.
(Conditions) A test piece of electroformed brick was immersed in molten glass heated to a temperature T2 in a crucible, at which the viscosity of the glass reached 10 ² dPa s, and held at T2 for 48 hours. The glass was then cooled to 20°C or below. The test piece was then removed from the crucible along with the surrounding glass, cut on a plane perpendicular to the contact surface between the glass and the test piece, horizontally ground, and mirror-polished. The maximum erosion of the test piece was measured for the resulting cross section using a projector.

The electroformed bricks used in the finger test are high-zirconia bricks containing 80% by mass or more of _ZrO2 expressed as a mass percentage based on oxides. The glass of this embodiment exhibits a high-zirconia brick erosion rate measured by the finger test of 0.20 mm/day or less, more preferably 0.15 mm/day or less, and even more preferably 0.13 mm/day or less; the lower the better. The erosion rate is an indicator of the glass's resistance to high-zirconia brick erosion and can be adjusted by the glass composition.

The glass transition temperature Tg of the glass of this embodiment is preferably 390°C or higher, more preferably 410°C or higher, and even more preferably 420°C or higher. If the glass transition temperature Tg is high, stress relaxation during chemical strengthening is less likely to occur, making it easier to achieve high strength. On the other hand, from the perspective of glass formability, etc., Tg is preferably 650°C or lower, and more preferably 600°C or lower. The above Tg may be, for example, 390 to 650°C.

The average thermal expansion coefficient of the glass of this embodiment at 50°C to 350°C is preferably 90×10 ^-7 /°C or more, more preferably 100×10 ^-7 /°C or more, and even more preferably 110×10 ^-7 /°C or more. On the other hand, in order to prevent the glass from cracking during molding, the average thermal expansion coefficient is preferably 150×10 ^-7 /°C or less, more preferably 140×10 ^-7 /°C or less. The average thermal expansion coefficient may be, for example, 90×10 ^-7 /°C to 150×10 ^-7 /°C.

The glass of this embodiment is crushed, and the difference between the glass transition point (Tg _DSC ) determined from a DSC curve obtained using a differential scanning calorimeter and the crystallization peak temperature (Tc) appearing in the lowest temperature range on the DSC curve is taken as (Tc - Tg). The (Tc - Tg) of the glass of this embodiment is preferably 80°C or higher, more preferably 85°C or higher, even more preferably 90°C or higher, and particularly preferably 95°C or higher. When (Tc - Tg) is large, the glass is easier to heat and process, for example, for bending. (Tc - Tg) is preferably 150°C or lower, more preferably 140°C or lower. The (Tc - Tg) may be, for example, 80 to 150°C.

The Tg _DSC may not coincide with the glass transition temperature (Tg) determined from a thermal expansion curve. Furthermore, since Tg _DSC is measured after crushing the glass, measurement error is likely to be large. However, in order to evaluate the relationship with the crystallization peak temperature, it is more appropriate to use the Tg _DSC determined by the same DSC measurement than the Tg determined from a thermal expansion curve.

The Young's modulus of the glass of this embodiment is preferably 75 GPa or more, more preferably 80 GPa or more, and even more preferably 85 GPa or more, and is preferably 130 GPa or less, more preferably 125 GPa or less, and even more preferably 120 GPa or less. The Young's modulus may be, for example, 75 to 130 GPa.

The Vickers hardness of the glass of this embodiment is preferably 500 or more, more preferably 550 or more, and preferably 1100 or less, more preferably 1050 or less, and even more preferably 1000 or less. The Vickers hardness may be, for example, 500 to 1100.

The thickness of the glass in this embodiment is, for example, 2000 μm or less, preferably 1500 μm or less, more preferably 1000 μm or less, even more preferably 900 μm or less, particularly preferably 800 μm or less, and most preferably 700 μm or less. Furthermore, to obtain sufficient strength, the thickness is, for example, 200 μm or more, preferably 400 μm or more, more preferably 500 μm or more, and even more preferably 600 μm or more. The thickness may be, for example, 200 to 2000 μm.

The shape of the glass of this embodiment may be plate-like or may be any other shape, depending on the product to which it is applied, its intended use, etc. Furthermore, when the glass of this embodiment is plate-like glass, i.e., a glass plate, the glass plate may have a rim shape with a different thickness around the periphery. Furthermore, the shape of the glass plate is not limited to this; for example, the two main surfaces do not have to be parallel to each other, and one or both of the two main surfaces may be entirely or partially curved. More specifically, the glass plate may be, for example, a flat glass plate without warping, or a curved glass plate with a curved surface.

The glass of this embodiment can be used as cover glass for mobile electronic devices such as mobile phones, smartphones, personal digital assistants (PDAs), and tablet devices. It is also useful as cover glass for electronic devices that are not intended to be portable, such as televisions (TVs), personal computers (PCs), and touch panels. It is also useful as building materials such as window glass, tabletops, and the interiors of automobiles and airplanes, as well as the cover glass for these materials.

Glass of this type can be bent or formed into shapes other than flat before or after chemical strengthening, making it useful for applications such as housings with curved surfaces.

<Glass-ceramics>
The glass of this embodiment is preferably the crystallized glass that contains crystalline phase.Crystallized glass is obtained by heating amorphous glass to crystallize it.The glass composition of the entire crystallized glass is the same as the composition of the amorphous glass before crystallization, and the preferred embodiment of the composition of crystallized glass is the same as above.

In this specification, "crystallized glass containing a crystalline phase" refers to glass in which diffraction peaks indicating crystals are observed in the XRD pattern obtained by powder X-ray diffraction (XRD) method.

When the glass of this embodiment is glass-ceramics, the glass-ceramics preferably contain at least one crystal selected from the group consisting of Li ₂ Si ₂ O ₅ (lithium disilicate), LiAlSi ₂ O ₆ (β-spodumene), LiAlSi ₄ O ₁₀ (petalite), Li ₃ PO ₄ (lithium phosphate), and β-quartz solid solution. The inclusion of the above crystals in the glass-ceramics more preferably results in a glass that exhibits high strength when chemically strengthened. The crystals contained in the glass-ceramics are more preferably at least one crystal selected from the group consisting of Li ₂ Si ₂ O ₅ , LiAlSi ₂ O ₆ , and LiAlSi ₄ O ₁₀ , and more preferably contain Li ₂ Si ₂ O _5. The presence of the above crystals in the glass-ceramics can be confirmed from an X-ray diffraction spectrum.

The crystallization rate of the glass of this embodiment is preferably 5% or more, more preferably 10% or more, even more preferably 15% or more, and particularly preferably 20% or more, in order to increase mechanical strength. The crystallization rate is preferably 80% or less, more preferably 70% or less, and particularly preferably 60% or less, in order to increase transparency. A low crystallization rate is also advantageous in that it is easy to heat and bend the glass. The crystallization rate may be, for example, 5 to 80%.

The crystallinity rate can be calculated from the X-ray diffraction intensity using the Rietveld method. The Rietveld method is described in the "Crystal Analysis Handbook" (Kyoritsu Shuppan, 1999, pp. 492-499), edited by the Editorial Committee of the Crystallographic Society of Japan.

The average particle size of the precipitated crystals in the crystallized glass is preferably 80 nm or less, more preferably 60 nm or less, even more preferably 50 nm or less, particularly preferably 40 nm or less, and most preferably 30 nm or less. There is no particular lower limit to the average particle size, but it is usually 5 nm or more, for example. The average particle size can be determined from a transmission electron microscope (TEM) image.

When the glass of this embodiment is crystallized glass, the average thermal expansion coefficient of the crystallized glass at 50 ° C to 350 ° C is preferably 90 × 10 ^-7 / ° C or more, more preferably 100 × 10 ^-7 / ° C or more, even more preferably 110 × 10 ^-7 / ° C or more, particularly preferably 120 × 10 ^-7 / ° C or more, and most preferably 130 × 10 ^-7 / ° C or more. In order to suppress the occurrence of cracks due to the difference in thermal expansion coefficient during chemical strengthening, the average thermal expansion coefficient is preferably 160 × 10 ^-7 / ° C or less, more preferably 150 × 10 ^-7 / ° C or less, and even more preferably 140 × 10 ^-7 / ° C or less. The average thermal expansion coefficient may be, for example, 90 × 10 ^-7 / ° C to 160 × 10 ^-7 / ° C.

Ceramics glass has a high hardness because it contains crystals. This makes it scratch-resistant and highly abrasion-resistant. When the glass of this embodiment is crystallized glass, in order to increase abrasion resistance, the Vickers hardness is preferably 600 or higher, more preferably 700 or higher, even more preferably 730 or higher, particularly preferably 750 or higher, and most preferably 780 or higher. From the standpoint of processability, the Vickers hardness of the crystallized glass is preferably 1100 or lower, more preferably 1050 or lower, and even more preferably 1000 or lower. The Vickers hardness may be, for example, 600 to 1100.

When the glass of this embodiment is glass-ceramics, the Young's modulus of the glass-ceramics is preferably 85 GPa or more, more preferably 90 GPa or more, even more preferably 95 GPa or more, and particularly preferably 100 GPa or more, in order to suppress warping due to strengthening during chemical strengthening. The glass-ceramics may be polished before use. For ease of polishing, the Young's modulus of the glass-ceramics is preferably 130 GPa or less, more preferably 125 GPa or less, and even more preferably 120 GPa or less. The Young's modulus may be, for example, 85 to 130 GPa.

When the glass of this embodiment is crystallized glass, the fracture toughness value of the crystallized glass is preferably 0.8 MPa·m ^1/2 or more, more preferably 0.85 MPa·m ^1/2 or more, and even more preferably 0.9 MPa·m ^1/2 or more. This is because, when the crystallized glass is chemically strengthened, fragments are less likely to scatter when broken. The upper limit of the fracture toughness value is not particularly limited, but is usually, for example, 2.0 MPa·m ^1/2 or less. The fracture toughness value may be, for example, 0.8 to 2.0 MPa·m ^1/2 .

Chemically strengthened glass
The chemically strengthened glass of this embodiment has a composition at the center in the thickness direction, expressed in mole percentages based on oxides, of 60.0 to 75.0% SiO ₂ , 2.0 to 20.0% Al ₂ O ₃ , 20.0 to 30.0% Li ₂ O, 0.0 to 10.0% MgO, 0.0 to 10.0% CaO, 2.00 to 10.00% ZrO ₂ , and 0.50 to 5.00% P ₂ O ₅ , and is substantially free of Y ₂ O _3. Furthermore, in the chemically strengthened glass of this embodiment, the value of X represented by the following formula (1) in the composition at the center in the thickness direction is 0.70 or less.
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis at the center in the thickness direction.

The chemically strengthened glass of this embodiment refers to glass that has been subjected to a chemical strengthening treatment. The chemically strengthened glass of this embodiment can be produced, for example, by chemically strengthening the glass of this embodiment described above.

In chemically strengthened glass, a compressive stress layer due to ion exchange typically forms on the surface of the glass. Therefore, the glass composition of the non-ion-exchanged portion of the chemically strengthened glass, i.e., the center portion in the thickness direction, matches the composition of the glass of this embodiment described above, which is the base composition of chemically strengthened glass. Furthermore, even in the ion-exchanged portion, the concentrations of components other than alkali metal oxides basically do not change from the base composition. The preferred glass composition of the center portion in the thickness direction of the chemically strengthened glass of this embodiment is the same as that described above for the glass composition of this embodiment.

The chemically strengthened glass of this embodiment has a thickness t (unit: μm), a compressive stress layer depth (DOC) of 0.15t or more, a compressive stress value (CS ₅₀ ) at a depth of 50 μm from the glass surface of 30 MPa or more, and a compressive stress value (CS ₁₀₀ ) at a depth of 100 μm from the glass surface of -10 MPa or more.

From the perspective of improving strength, the chemically strengthened glass of this embodiment preferably has a depth of compressive stress layer (DOC) (unit: μm), which is the depth at which the compressive stress value (CS) becomes zero, of 0.15t or more. The DOC is preferably 0.15t or more, more preferably 0.15t + 5 or more, and even more preferably 0.15t + 10 or more. From the perspective of suppressing an increase in internal tensile stress (CT), the DOC is preferably 0.25t or less, more preferably 0.25t - 5 or less, and even more preferably 0.25t - 10 or less. The DOC may be, for example, 0.15t to 0.25t.

In the chemically strengthened glass of this embodiment, CS ₅₀ is preferably 30 MPa or more from the viewpoint of improving drop strength against #180 sandpaper. CS ₅₀ is more preferably 60 MPa or more, even more preferably 90 MPa or more, and particularly preferably 120 MPa or more. CS ₅₀ is preferably 300 MPa or less, more preferably 250 MPa or less, and even more preferably 200 MPa or less from the viewpoint of suppressing glass fracture (explosive fracture when scratched) due to an increase in CT. The CS ₅₀ may be, for example, 30 to 300 MPa.

In the chemically strengthened glass of this embodiment, CS ₁₀₀ is preferably -10 MPa or more from the viewpoint of improving drop strength against #80 sandpaper. CS ₁₀₀ is more preferably 0 MPa or more, even more preferably 10 MPa or more, and particularly preferably 20 MPa or more. From the viewpoint of suppressing scattering of fragments when glass is crushed, CS ₁₀₀ is preferably 100 MPa or less, more preferably 80 MPa or less, and even more preferably 60 MPa or less. The CS ₁₀₀ may be, for example, -10 to 100 MPa. Note that when the CS ₁₀₀ takes a negative value, it means that the CS ₁₀₀ is a tensile stress.

The chemically strengthened glass of this embodiment preferably has a DOC of 0.15t or more, a CS ₅₀ of 30 MPa or more, and a CS ₁₀₀ of −10 MPa or more, and more preferably has a DOC of 0.15t + 5 or more, a CS ₅₀ of 60 MPa or more, and a CS ₁₀₀ of 0 MPa or more. It is more preferable that the DOC is 0.15t + 10 or more, the CS ₅₀ is 90 MPa or more, and the CS ₁₀₀ is 10 MPa or more.

In this specification, the above DOC, CS ₅₀ and CS ₁₀₀ are the results obtained by measuring the stress values of chemically strengthened glass using a measuring instrument SLP-2000 manufactured by Orihara Seisakusho Co., Ltd.

The preferred thickness (t), shape, and uses of the chemically strengthened glass of this embodiment are the same as those described above for the glass of this embodiment.

<Glass manufacturing method>
A method for producing glass according to this embodiment includes heating and melting glass raw materials in a melting furnace. The melting furnace includes electroformed bricks containing 85 mass% or more _{of Al2O3} , expressed as mass percentages based on oxides. The glass contains, expressed as mole percentages based on oxides, 60.0 to 75.0% _SiO2 , 2.0 to 20.0% _Al2O3 , 20.0 to 30.0% _Li2O , 0.0 to 10.0% MgO, 0.0 to 10.0% CaO, 2.00 to 10.00% _{ZrO2 ,} and 0.50 to 5.00% _P2O5 , and is substantially free of _{Y2O3 .} The value of X _, as expressed by the following formula (1), is 0.70 or less:
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis.

The melting furnace used in the method for producing glass of this embodiment contains high-alumina bricks, which are electroformed bricks containing 85 mass% or more _{of Al2O3} expressed as a mass percentage based on oxides. More specifically, at least a portion of the furnace materials constituting the melting furnace contain the high-alumina bricks. The furnace materials containing the high-alumina bricks are preferably arranged at least in a region of the melting furnace that comes into contact with the heated and molten glass frit, more preferably in a region that comes into contact with the heated and molten glass frit having a viscosity of ^103.5 dPa·s. Even when the furnace materials of the melting furnace contain high-alumina bricks, when producing glass of this embodiment having a specific composition, erosion of the bricks during melting of the glass frit can be suppressed.

The melting furnace preferably further includes high-zirconia bricks, which are electrocast bricks containing 80% by mass or more of _ZrO2 expressed as a mass percentage based on oxides. More specifically, at least a portion of the furnace materials constituting the melting furnace preferably include the high-zirconia bricks. The furnace materials including the high-zirconia bricks are more preferably arranged in at least a region of the melting furnace that comes into contact with the heated and melted glass frit, and even more preferably in at least a region that comes into contact with the heated and melted glass frit having a viscosity of 10 ² dPa s. Even when the furnace materials of the melting furnace include high-zirconia bricks, erosion of the bricks during melting of the glass frit can be suppressed when producing the glass of this embodiment having a specific composition.

In the method for producing glass of this embodiment, glass raw materials are mixed so as to obtain glass of the specified composition described above, and then heated and melted in a glass melting furnace. The preferred composition of the glass obtained by the method for producing glass of this embodiment is the same as that described above for the glass of this embodiment.

In the glass manufacturing method of this embodiment, the value of Y, expressed by the following formula ₍₂ ) using the _ZrO2 content (unit: mol % expressed as a molar percentage based on the oxide) of the obtained glass and the _Al2O3 content (unit: mol % expressed as a molar percentage based on the oxide) of the electroformed bricks contained in the melting furnace, is preferably 0.02 to 0.10. The electroformed bricks referred to here refer to electroformed bricks that are contained in at least a portion of the furnace materials constituting the melting furnace and are arranged at least in a region in the melting furnace that contacts the heated and molten glass raw material, and contain 85 mass % or _more of _Al2O3 expressed as a mass percentage based on the oxide. When such electroformed _bricks include multiple electroformed bricks with different _Al2O3 contents, it is preferable that the value of Y be 0.02 to 0.10 for at least some of the multiple electroformed bricks, and more preferably the value of Y be 0.02 to 0.10 for all of the electroformed bricks.
Y = ( _ZrO2 content of glass) / ( _{Al2O3 content} of electroformed brick) Formula (2)

When the value of Y is 0.02 to 0.10, the brick erosion suppression effect in the glass manufacturing method of this embodiment is more preferably achieved. The value of Y is more preferably 0.03 or more, and even more preferably 0.04 or more. The value of Y is more preferably 0.09 or less, and even more preferably 0.08 or less.

Other manufacturing processes and conditions may be those known in the art. For example, after the glass raw materials are heated and melted in a melting furnace as described above, the molten glass may be homogenized by bubbling, stirring, adding a fining agent, etc., formed into the desired shape such as a glass plate, and slowly cooled. Alternatively, the molten glass may be formed into a block, slowly cooled, and then cut into a plate.

Glass forming methods include, for example, the float method, press method, fusion method, and downdraw method. The float method is particularly preferred when producing large glass sheets. Continuous forming methods other than the float method, such as the fusion method and downdraw method, are also preferred.

The molded glass is then subjected to grinding and polishing processes as necessary. The resulting glass may also be subjected to the chemical strengthening process described below to obtain chemically strengthened glass. In this case, it is preferable to cut the glass to a specified shape and size or to chamfer the glass before carrying out the chemical strengthening process. This is because the subsequent chemical strengthening process will form a compressive stress layer on the edge as well.

<Method for producing crystallized glass>
When the glass of this embodiment is crystallized glass, the amorphous glass obtained by the above procedure is subjected to a heat treatment to obtain crystallized glass.

The heat treatment is preferably a two-stage heat treatment in which the temperature is raised from room temperature to a first treatment temperature and maintained for a certain period of time, and then the temperature is maintained at a second treatment temperature that is higher than the first treatment temperature for a certain period of time.

When using a two-stage heat treatment, the first treatment temperature is preferably in a temperature range where the crystal nucleation rate is high for that glass composition, and the second treatment temperature is preferably in a temperature range where the crystal growth rate is high for that glass composition. Furthermore, it is preferable that the holding time at the first treatment temperature be long enough to generate a sufficient number of crystal nuclei. By generating a large number of crystal nuclei, the size of each crystal becomes small, resulting in highly transparent crystallized glass.

The first treatment temperature is, for example, 450°C to 700°C, the second treatment temperature is, for example, 600°C to 800°C, the holding time at the first treatment temperature is, for example, 1 hour to 6 hours, and the holding time at the second treatment temperature is, for example, 1 hour to 6 hours.

<<Method for manufacturing chemically strengthened glass>>
The chemically strengthened glass of this embodiment is produced by chemically strengthening the amorphous glass or crystallized glass described above. That is, the method for producing the chemically strengthened glass of this embodiment includes chemically strengthening the glass or crystallized glass of this embodiment.

In the method for producing chemically strengthened glass of this embodiment, the chemical strengthening is preferably performed using a molten salt composition containing sodium and less than 5% by mass of potassium. In the method for producing chemically strengthened glass of this embodiment, the chemical strengthening treatment may be performed in two or more stages, but one-stage strengthening is preferred to increase productivity.

Chemical strengthening is performed, for example, by immersing the glass in a molten salt composition such as sodium nitrate heated to 360 to 600°C for 0.1 to 500 hours. The heating temperature for the molten salt composition is preferably 375 to 500°C, and the immersion time for the glass in the molten salt composition is preferably 0.3 to 200 hours.

The molten salt composition used in this embodiment of the method for producing chemically strengthened glass preferably contains sodium and has a potassium content of less than 5 mass% calculated as potassium nitrate. The potassium content is more preferably less than 2 mass% calculated as potassium nitrate, and it is even more preferable that the molten salt composition contains substantially no potassium. "Substantially no potassium" means that the composition does not contain any potassium, or that it may contain potassium as an impurity that is unavoidably mixed in during production.

Examples of the reinforcing salts contained in the molten salt composition include nitrates, sulfates, carbonates, and chlorides. Nitrates include, for example, lithium nitrate and sodium nitrate. Sulfates include, for example, lithium sulfate and sodium sulfate. Carbonates include, for example, lithium carbonate and sodium carbonate. Chlorides include, for example, lithium chloride, sodium chloride, cesium chloride, and silver chloride. These reinforcing salts may be used alone or in combination.

Appropriate conditions for chemical strengthening should be selected taking into consideration the glass composition (characteristics), the type of strengthening salt, and the desired chemical strengthening characteristics.

<Display devices, electronic device products, solar cell modules>
The display device of this embodiment includes the glass or chemically strengthened glass of this embodiment and a display. Such a display device may be used in electronic devices such as mobile phones, smartphones, and tablet terminals, as well as electronic devices such as car navigation systems installed in vehicles such as automobiles.

The electronic device product of this embodiment has the glass or chemically strengthened glass of this embodiment as part of its constituent parts. Such electronic device products may be, for example, electronic devices such as mobile phones, smartphones, and tablet terminals, or electronic devices such as car navigation systems installed in vehicles such as automobiles.

The solar cell module of this embodiment includes the glass or chemically strengthened glass of this embodiment. The glass or chemically strengthened glass can be used, for example, as a transparent cover member for the light-receiving surface of the solar cell module.

As described above, the present specification discloses the following configurations.
<1> Molar percentage based on oxides,
_SiO2 60.0 to 75.0%,
2.0 to 20.0% Al ₂ O ₃ ,
20.0 to 30.0% Li ₂ O,
MgO 0.0 to 10.0%,
CaO 0.0 to 10.0%,
Contains 2.00 to 10.00% _ZrO2 and 0.50 to 5.00% _{P2O5 ;}
Substantially does not contain Y ₂ O ₃ , and
A glass in which the value of X represented by the following formula (1) is 0.70 or less.
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis.
<2> Molar percentage based on oxides,
The _ZrO2 is contained in an amount of 3.00 to 10.00%;
The glass according to <1>, containing 0.00 to 0.10% of TiO ₂ .
<3> The glass according to <1> or _<2> , wherein the total content of _ZrO2 , _P2O5 , and _TiO2 is 3.00% or more, expressed in mole percentage based on oxides.
<4> Crystallized glass,
The glass according to any one of <1> to <3>, comprising at least one crystal selected from the group consisting of Li ₂ Si ₂ O ₅ (lithium disilicate), LiAlSi ₂ O ₆ (β-spodumene), LiAlSi ₄ O ₁₀ (petalite), Li ₃ PO ₄ (lithium phosphate), and β-quartz solid solution.
<5> The glass according to any one of <1> to <4>, wherein the amount of corrosion of an electroformed brick containing 85 mass% or more of Al ₂ O ₃ expressed as a mass percentage based on oxides, as measured by a finger test method under the following conditions, is 0.090 mm/day or less.
(Conditions) The glass is heated to a temperature T2 in a crucible, at which the viscosity of the glass becomes 10 ² dPa·s, and then cooled to a temperature T3.5, at which the viscosity of the glass becomes 10 ^3.5 dPa·s. A test piece of electroformed brick is immersed in the resulting glass and held at T3.5 for 48 hours. The glass is then cooled to 20°C or below. The test piece is removed from the crucible along with the surrounding glass, and the test piece is cut on a plane perpendicular to the contact surface between the glass and the test piece, horizontally ground, and mirror-polished. The maximum erosion amount of the test piece is measured for the resulting cross section using a projector.
<6> The glass according to any one of <1> to <5>, wherein the amount of corrosion of an electroformed brick containing 80 mass% or more of _ZrO2 , expressed as a mass percentage based on oxides, measured by a finger test method under the following conditions is 0.20 mm/day or less.
(Conditions) A test piece of electroformed brick was immersed in molten glass heated to a temperature T2 in a crucible, at which the viscosity of the glass reached 10 ² dPa s, and held at T2 for 48 hours. The glass was then cooled to 20°C or below. The test piece was then removed from the crucible along with the surrounding glass, cut on a plane perpendicular to the contact surface between the glass and the test piece, horizontally ground, and mirror-polished. The maximum erosion of the test piece was measured for the resulting cross section using a projector.
<7> The composition of the center portion in the thickness direction is expressed in mole percentage based on oxides,
_SiO2 60.0 to 75.0%,
2.0 to 20.0% Al ₂ O ₃ ,
20.0 to 30.0% Li ₂ O,
MgO 0.0 to 10.0%,
CaO 0.0 to 10.0%,
Contains 2.00 to 10.00% _ZrO2 and 0.50 to 5.00% _{P2O5 ;}
Substantially does not contain Y ₂ O ₃ , and
Chemically strengthened glass, wherein the value of X represented by the following formula (1) is 0.70 or less.
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis at the center in the thickness direction.
<8> The composition of the center portion in the thickness direction is expressed in mole percentage based on oxides,
The _ZrO2 is contained in an amount of 3.00 to 10.00%;
The chemically strengthened glass according to <7>, containing 0.00 to 0.10% of TiO ₂ .
<9> The thickness is t (unit: μm), and the depth of compressive stress layer (DOC) is 0.15t or more;
The compressive stress value (CS ₅₀ ) at a depth of 50 μm from the glass surface is 30 MPa or more,
<7> or <8>, wherein the chemically strengthened glass has a compressive stress value (CS ₁₀₀ ) of −10 MPa or more at a depth of 100 μm from the glass surface.
<10> A method for producing glass,
The method comprises heating and melting glass raw materials in a melting furnace,
The melting furnace includes electroformed bricks containing 85 mass% or more of Al ₂ O ₃ expressed as a mass percentage based on oxides,
The glass has, in mole percentage on an oxide basis,
_SiO2 60.0 to 75.0%,
2.0 to 20.0% Al ₂ O ₃ ,
20.0 to 30.0% Li ₂ O,
MgO 0.0 to 10.0%,
CaO 0.0 to 10.0%,
Contains 2.00 to 10.00% _ZrO2 and 0.50 to 5.00% _{P2O5 ;}
Substantially does not contain Y ₂ O ₃ , and
A method for producing glass, wherein the value of X represented by the following formula (1) is 0.70 or less:
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis.
<11> The glass contains, in terms of mole percentage based on oxides,
The _ZrO2 is contained in an amount of 3.00 to 10.00%;
The method for producing glass according to <10>, wherein the glass contains 0.00 to 0.10% of TiO ₂ .
<12> The method for producing glass according to <10> or <11>, wherein the value of Y, expressed by the following formula (2) using the _ZrO2 content (unit: mol % expressed as a molar percentage based on oxides) of the glass and _{the Al2O3} content (unit: mol % expressed as a molar percentage based on oxides) of the electroformed brick, is 0.02 to 0.10:
Y = ( _ZrO2 content of glass) / ( _{Al2O3 content} of electroformed brick) Formula (2)
<13> The method for producing glass according to any one of <10> to <12>, wherein the melting furnace further includes electroformed bricks containing 80 mass% or more of _ZrO2 expressed as a mass percentage based on oxides.
<14> A method for producing chemically strengthened glass, comprising chemically strengthening the glass according to any one of <1> to <6>.
<15> The method for producing chemically strengthened glass according to <14>, wherein the chemical strengthening is chemical strengthening using a molten salt composition containing sodium and having a potassium content of less than 5 mass%.
<16> A display device comprising the glass according to any one of <1> to <6> or the chemically strengthened glass according to any one of <7> to <9> and a display.
<17> An electronic device product having the glass according to any one of <1> to <6> or the chemically strengthened glass according to any one of <7> to <9> as a part of a component.
<18> A solar cell module having the glass according to any one of <1> to <6> or the chemically strengthened glass according to any one of <7> to <9>.

The present invention will be described in detail below using examples. However, the present invention is not limited to the following descriptions. Examples 1 to 6 are working examples, and Examples 7 to 12 are comparative examples.

[Glass production and brick erosion measurement]
Glass was prepared and the amount of erosion of the brick was measured using the finger test method. Glass raw materials were mixed to obtain the glass composition shown in Table 1, expressed in terms of oxide-based molar percentage, to form 190 ml of cullet, which was then placed in a 300 ml platinum crucible. The glass raw materials were heated at a rate of 300°C/hour to a temperature T2 at which the viscosity of the glass reached 10 ² dPa·s and maintained at this temperature for 6 hours to melt the glass. The molten glass was then cooled to a temperature T3.5 at which the viscosity of the glass reached 10 ^3.5 dPa·s. Test pieces were also prepared: electroformed bricks ("MB-G" manufactured by AGC Ceramics Co., Ltd.) measuring 25 mm x 15 mm x 73 mm and containing 95% Al ₂ O ₃ by mass, expressed in terms of oxide-based mass percentage. The test specimen was immersed in the T3.5 molten glass by at least 65% of its long side (73 mm) and held at T3.5 for 48 hours. The glass was then cooled to 20°C at a rate of 300°C/hour. The test specimen, along with the surrounding glass, was removed from the crucible, cut along a plane perpendicular to the contact surface between the glass and the test specimen, horizontally ground, and mirror-polished. The maximum erosion depth of the resulting cross section was measured using a projector (Nikon V12BDC). The measurement results are shown in Table 1 as "High-alumina brick erosion depth."

Furthermore, the erosion amount of the brick was measured in the same manner as above, except that the test specimen was an electroformed brick ("ZB-X9510" manufactured by AGC Ceramics Co., Ltd.) containing 94.5 mass% _ZrO2 , expressed as a mass percentage based on the oxide, and the molten glass was not cooled to T3.5, but the test specimen was immersed in the molten glass at T2 and held at T2 for 48 hours. The measurement results are shown in Table 1 as "Erosion amount of high-zirconia brick."

The value of X expressed by formula (1) and the total content of _ZrO2 , _P2O5 , _{and TiO2} were calculated from the glass compositions listed in Table 1. These are shown in Table 1 as "X value" and "[ _ZrO2 ] + [ _P2O5 ] + [ _TiO2 ] _, " respectively.

Furthermore, the value of Y' represented by the following formula (3) was calculated using the _ZrO2 content (unit: mol % expressed as a molar percentage based on oxides) of the glasses of Examples 1 to ₁₂ and the _Al2O3 content (unit: mol % expressed as a molar percentage based on oxides; 93.03 mol %) of the electroformed bricks used in the brick erosion amount measurements. This is shown as "Y'value" in Table 1. The Y' value corresponds to the value of Y represented by the above formula (2) when the electroformed bricks used in the brick erosion amount measurements are used as at least a part of the furnace material of a melting furnace.
Y' = ( _ZrO2 content of glass) / ( _{Al2O3 content} of electroformed brick) Formula (3)

As shown in Table 1, the glass of this embodiment was found to have low corrosion resistance against high-alumina bricks. Furthermore, the glasses of Examples 1 to 3 in particular were found to have low corrosion resistance against high-zirconia bricks.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on Japanese patent applications filed on June 7, 2024 (Patent Application No. 2024-092882), January 14, 2025 (Patent Application No. 2025-004715), and February 17, 2025 (Patent Application No. 2025-023654), the contents of which are incorporated herein by reference.

The glass according to this embodiment has low brick corrosion resistance, so it can be suitably manufactured in a melting furnace constructed with furnace materials that include bricks.

Claims (18)

In mole percentage based on oxides,
_SiO2 60.0 to 75.0%,
2.0 to 20.0% Al ₂ O ₃ ,
20.0 to 30.0% Li ₂ O,
MgO 0.0 to 10.0%,
CaO 0.0 to 10.0%,
Contains 2.00 to 10.00% _ZrO2 and 0.50 to 5.00% _{P2O5 ;}
Substantially does not contain Y ₂ O ₃ , and
A glass in which the value of X represented by the following formula (1) is 0.70 or less.
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis. In mole percentage based on oxides,
The _ZrO2 is contained in an amount of 3.00 to 10.00%;
2. The glass of claim 1, containing 0.00 to 0.10% _TiO2 . 3. The glass according to claim 1, wherein the total content of _ZrO2 , _{P2O5 ,} and _TiO2 is 3.00% or more, expressed in mole percentage on an oxide basis. A crystallized glass,
3. The glass according to claim 1, comprising at least one crystal selected from the group consisting of Li ₂ Si ₂ O ₅ (lithium disilicate), LiAlSi ₂ O ₆ (β-spodumene), LiAlSi ₄ O ₁₀ (petalite), Li ₃ PO ₄ (lithium phosphate), and β-quartz solid solution. 3. The glass according to claim 1, wherein the amount of corrosion of an electroformed brick containing 85 mass % or more of Al ₂ O ₃ expressed as a mass percentage based on oxides, as measured by a finger test method under the following conditions, is 0.090 mm/day or less.
(Conditions) The glass is heated to a temperature T2 in a crucible, at which the viscosity of the glass becomes 10 ² dPa·s, and then cooled to a temperature T3.5, at which the viscosity of the glass becomes 10 ^3.5 dPa·s. A test piece of electroformed brick is immersed in the resulting glass and held at T3.5 for 48 hours. The glass is then cooled to 20°C or below. The test piece is removed from the crucible along with the surrounding glass, and the test piece is cut on a plane perpendicular to the contact surface between the glass and the test piece, horizontally ground, and mirror-polished. The maximum erosion amount of the test piece is measured for the resulting cross section using a projector. The glass according to claim 5, wherein the amount of corrosion of an electroformed brick containing 80 mass % or more of ZrO ₂ expressed as a mass percentage based on oxides, as measured by a finger test method under the following conditions, is 0.20 mm/day or less.
(Conditions) A test piece of electroformed brick was immersed in molten glass heated to a temperature T2 in a crucible, at which the viscosity of the glass reached 10 ² dPa s, and held at T2 for 48 hours. The glass was then cooled to 20°C or below. The test piece was then removed from the crucible along with the surrounding glass, cut on a plane perpendicular to the contact surface between the glass and the test piece, horizontally ground, and mirror-polished. The maximum erosion of the test piece was measured for the resulting cross section using a projector. The composition of the center in the thickness direction is expressed as mole percentage based on oxides,
_SiO2 60.0 to 75.0%,
2.0 to 20.0% Al ₂ O ₃ ,
20.0 to 30.0% Li ₂ O,
MgO 0.0 to 10.0%,
CaO 0.0 to 10.0%,
Contains 2.00 to 10.00% _ZrO2 and 0.50 to 5.00% _{P2O5 ;}
Substantially does not contain Y ₂ O ₃ , and
Chemically strengthened glass, wherein the value of X represented by the following formula (1) is 0.70 or less.
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis at the center in the thickness direction. The composition of the center portion in the thickness direction is expressed in mole percentage based on oxides:
The _ZrO2 is contained in an amount of 3.00 to 10.00%;
The chemically strengthened glass according to claim 7, containing 0.00 to 0.10% of _TiO2 . The thickness is t (unit: μm), and the depth of compressive stress layer (DOC) is 0.15t or more;
The compressive stress value (CS ₅₀ ) at a depth of 50 μm from the glass surface is 30 MPa or more,
The chemically strengthened glass according to claim 7 or 8, wherein the compressive stress value (CS ₁₀₀ ) at a depth of 100 μm from the glass surface is −10 MPa or more. A method for producing glass, comprising:
The method comprises heating and melting glass raw materials in a melting furnace,
The melting furnace includes electroformed bricks containing 85 mass% or more of Al ₂ O ₃ expressed as a mass percentage based on oxides,
The glass has, in mole percentage on an oxide basis,
_SiO2 60.0 to 75.0%,
2.0 to 20.0% Al ₂ O ₃ ,
20.0 to 30.0% Li ₂ O,
MgO 0.0 to 10.0%,
CaO 0.0 to 10.0%,
Contains 2.00 to 10.00% _ZrO2 and 0.50 to 5.00% _{P2O5 ;}
Substantially does not contain Y ₂ O ₃ , and
A method for producing glass, wherein the value of X represented by the following formula (1) is 0.70 or less:
X=([TiO ₂ ]+[P ₂ O ₅ ])/[ZrO ₂ ] Formula (1)
Here, [ ] means the content of each component in the brackets expressed as mole percentage on an oxide basis. The glass has, in mole percentage on an oxide basis,
The _ZrO2 is contained in an amount of 3.00 to 10.00%;
The method for producing glass according to claim 10, wherein the glass contains 0.00 to 0.10% of _TiO2 . The method for producing glass according to claim 10 or 11, wherein the value of Y, expressed by the following formula ( ₂ ) using the _ZrO2 content (unit: mol % expressed as a molar percentage based on oxide) of the glass and the _Al2O3 content (unit: mol % expressed as a molar percentage based on oxide) of the electroformed brick, is 0.02 to 0.10:
Y = ( _ZrO2 content of glass) / ( _{Al2O3 content} of electroformed brick) Formula (2) The method for producing glass according to claim 10 or 11, wherein the melting furnace further includes electroformed bricks containing 80 mass % or more of ZrO ₂ expressed as a mass percentage on an oxide basis. A method for producing chemically strengthened glass, comprising chemically strengthening the glass of claim 1 or 2. The method for producing chemically strengthened glass according to claim 14, wherein the chemical strengthening is performed using a molten salt composition containing sodium and less than 5% by mass of potassium. A display device comprising the chemically strengthened glass of claim 7 or 8 and a display. An electronic device product having the chemically strengthened glass of claim 7 or 8 as part of its constituent parts. A solar cell module comprising the chemically strengthened glass of claim 7 or 8.