WO2024162064A1 - Glass including crystalline phase - Google Patents

Abstract

A glass including a crystalline phase, wherein, in an X-ray diffraction spectrum obtained by an X-ray diffraction method, when the diffraction intensity of a diffraction peak present at the position with a diffraction angle 2θ=23.50° to 24.00° is I₁, the diffraction intensity of a diffraction peak present at the position with a diffraction angle 2θ=24.05° to 24.55° is I₂, the diffraction intensity of a diffraction peak present at the position with a diffraction angle 2θ=24.60° to 25.05° is I₃, and the diffraction intensity of a diffraction peak present at the position with a diffraction angle 2θ=25.20° to 26.60° is I₄, (I₃+I₄)/(I₁+I₂) is greater than or equal to 1.60.

Description

Glass containing crystalline phase

The present invention relates to glasses containing a crystalline phase.

Glass containing a crystalline phase may be used as the cover glass of a smartphone or as a glass component of the housing. While glass containing a crystalline phase can increase its strength, it has the problem that it is difficult to ensure transparency. Patent documents 1 to 4 disclose glass containing a crystalline phase with a specific composition and physical properties.

JP 2021-095333 A JP 2001-048584 A JP 2020-019659 A JP 2008-254984 A

The object of the present invention is to provide a glass containing a crystalline phase that has high transparency.

The inventors conducted extensive research focusing on the shape of the X-ray diffraction spectrum measured on glass containing a crystalline phase, and discovered that the glass exhibits high transparency when the intensities of multiple diffraction peaks appearing in a specific range on the X-ray diffraction spectrum satisfy a specific relationship, leading to the completion of the present invention.

The present invention provides the following:
(Configuration 1)
In the X-ray diffraction spectrum obtained by the X-ray diffraction method,
The diffraction intensity of the diffraction peak at the diffraction angle 2θ=23.50° to 24.00° is represented as I ₁ ,
The diffraction intensity of the diffraction peak at the diffraction angle 2θ of 24.05° to 24.55° is represented as I ₂ ,
The diffraction intensity of the diffraction peaks at the diffraction angle 2θ of 24.60° to 25.05° is represented as I ₃ ,
When the diffraction intensity of the diffraction peak existing at the diffraction angle 2θ=25.20° to 26.60° is defined as _I4 ,
( _I3 + _I4 )/( _I1 + _I2 ) is 1.60 or more;
Glass containing crystalline phases.
(Configuration 2)
2. The glass containing a crystalline phase according to claim 1, wherein (I ₃ +I ₄ )/(I ₁ +I ₂ ) is 4.50 or less.
(Configuration 3)
3. A glass comprising a crystalline phase according to claim 1 or 2, wherein _I4 is greater than _I3 .
(Configuration 4)
A glass comprising a crystalline phase according to any one of claims 1 to 3, wherein _I1 is greater than _I2 .
(Configuration 5)
5. A glass comprising a crystalline phase according to any one of claims 1 to 4, wherein _I3 is greater than _I1 .
(Configuration 6)
6. A glass comprising a crystalline phase according to any one of claims 1 to 5, wherein _I3 is greater than _I2 .
(Configuration 7)
A glass containing a crystalline phase according to any one of configurations 1 to 6, in which _I4 is the largest among _I1 to _I4 .
(Configuration 8)
8. A glass comprising a crystalline phase according to any one of claims 1 to 7, which has no diffraction peak at a diffraction angle 2θ of 26.60° to 27.10° in an X-ray diffraction spectrum.
(Configuration 9)
9. A glass comprising a crystalline phase according to any one of claims 1 to 8, which is a crystallized glass.
(Configuration 10)
The composition of the raw glass is expressed as mass% in terms of oxides,
_SiO2 content 65.0% to 85.0%,
Al ₂ O ₃ content: 3.0% to 15.0%;
_{P2O5 component} content: more than 0% to 5.0%;
Li ₂ O content: more than 5.0% to 15.0%;
_ZrO2 content: 0% to 10.0%;
MgO content: 0% to 5.0%
10. A glass comprising the crystalline phase according to any one of claims 1 to 9.

The present invention provides glass containing a crystalline phase that has high transparency.

FIG. 2 is a schematic diagram showing the relationship between diffraction peaks and peak intensities in an X-ray diffraction spectrum. 1 is an X-ray diffraction spectrum obtained in Example 1. 1 is an X-ray diffraction spectrum obtained in Example 9. 1 is an X-ray diffraction spectrum obtained in Comparative Example 1. 1 is an X-ray diffraction spectrum obtained in Comparative Example 2. 1 is an X-ray diffraction spectrum obtained in Comparative Example 3. 13 is an X-ray diffraction spectrum obtained in Comparative Example 4. 13 is an X-ray diffraction spectrum obtained in Comparative Example 5.

The following provides a detailed explanation of embodiments and examples of the glass containing a crystalline phase of the present invention. However, the present invention is not limited to the following embodiments and examples, and can be modified as appropriate within the scope of the object of the present invention.

[Glass containing crystalline phase]
In the glass containing a crystalline phase according to one embodiment of the present invention, the X-ray diffraction spectrum obtained by the X-ray diffraction method satisfies the following conditions. That is,
The diffraction intensity of the diffraction peak present at the diffraction angle 2θ=23.50° to 24.00° (hereinafter also referred to as “range 1”) is represented by I ₁ ,
The diffraction intensity of the diffraction peak present at the diffraction angle 2θ=24.05° to 24.55° (hereinafter also referred to as “range 2”) is I ₂ ,
The diffraction intensity of the diffraction peak present at the diffraction angle 2θ=24.60° to 25.05° (hereinafter also referred to as “range 3”) is represented by I ₃ ,
When the diffraction intensity of the diffraction peak existing at the position of the diffraction angle 2θ=25.20° to 26.60° (hereinafter also referred to as “range 4”) is _I4 ,
(I ₃ +I ₄ )/(I ₁ +I ₂ ) is 1.60 or more.
Hereinafter, the above relational expression "(I ₃ +I ₄ )/(I ₁ +I ₂ )" may be referred to as "expression (1)".

The glass containing the above crystal phase satisfies a specific condition (formula (1)) in the X-ray diffraction spectrum, and therefore exhibits high light transmittance and is excellent in transparency. For this reason, it can be used as a cover glass or housing member for a smartphone, a member for portable electronic devices such as a tablet PC or a wearable terminal, a protective protector used in a transport body such as a car or an airplane, a substrate for a head-up display, or the like, and the high transparency of the above glass can improve the utility value of each of the above devices.
Hereinafter, each component of the glass containing a crystalline phase of the present invention will be described.

<Formula (1)>
The present inventors have focused on the intensities of the diffraction peaks appearing in ranges 1 to 4 of the X-ray diffraction spectrum, and have found that glass containing a crystalline phase exhibits high transparency when the sum of the diffraction intensities of the diffraction peaks appearing in two places on the high angle side (ranges 3 and 4) is greater than the sum of the diffraction intensities of the diffraction peaks appearing in two places on the small angle side (ranges 1 and 2) by a certain amount. Formula (1) expresses this.

The glass containing a crystalline phase of the present invention may contain, as a crystalline phase, one or more crystalline phases selected from the group consisting of a crystalline phase derived from lithium disilicate (also called lithium disilicate or lithium disilicate), a crystalline phase derived from petalite, a crystalline phase derived from a β-quartz solid solution, and a crystalline phase derived from vergilite.
In one embodiment, the glass comprising crystalline phases of the present invention comprises a crystalline phase derived from lithium disilicate, a crystalline phase derived from petalite, a crystalline phase derived from a β-quartz solid solution, and a crystalline phase derived from vergilite.
In one embodiment, the crystalline phase-containing glasses of the present invention include a crystalline phase derived from lithium disilicate, a crystalline phase derived from vergielite, and a crystalline phase derived from a β-quartz solid solution.
In one embodiment, the crystalline phase-containing glass of the present invention comprises a crystalline phase derived from lithium disilicate and a crystalline phase derived from vergilite.

(Formula (1))
There is no particular limitation on (I ₃ +I ₄ )/(I ₁ +I ₂ ) as long as it is 1.60 or more.
(I ₃ +I ₄ )/(I ₁ +I ₂ ) may be, for example, 1.70 or more, 1.80 or more, or 1.90 or more.
There is no particular upper limit to the value of (I ₃ +I ₄ )/(I ₁ +I ₂ ), and it is, for example, 4.50 or less.

There is no particular limitation on the magnitude relationship between I ₁ to I ₄ , but in one embodiment, I ₄ is the largest among I ₁ to I ₄ .
There is no particular limitation on the magnitude relationship between _I1 and _I2 , but in one embodiment, _I1 is greater than _I2 ( _I1 > _I2 ), for example, _I1 is greater than twice _I2 ( _I1 > _2I2 ).
There is no particular limitation on the magnitude relationship between _I3 and _I4 , but in one embodiment, _I4 is greater than _I3 ( _I4 > _I3 ), for example, _I4 is greater than twice _I3 ( _I4 > _2I3 ).
There is no particular limitation on the magnitude relationship between _I1 and _I3 , but in one embodiment, _I3 is greater than _I1 ( _I3 > _I1 ).
There is no particular limitation on the magnitude relationship between _I2 and _I3 , but in one embodiment, _I3 is greater than _I2 ( _I3 > _I2 ).

It is not necessary that diffraction peaks exist in all four ranges, range 1 to range 4. For example, even if there are no diffraction peaks in either range 1 or 2, the glass contains a crystalline phase that belongs to the present invention as long as formula (1) is satisfied.

(X-ray diffraction spectrum)
"A diffraction peak at a diffraction angle 2θ=AA° to BB°" refers to a convex portion showing a maximum value of the X-ray diffraction spectrum in the range of diffraction angle 2θ=AA° to BB°, and when two or more diffraction peaks exist in the range, it refers to a diffraction peak having the maximum diffraction intensity. As is self-evident from the above, when there is no maximum value in the range of diffraction angle 2θ=AA° to BB°, there is no diffraction peak in the range. In addition, "diffraction peak" refers to a diffraction peak having a size that can be clearly distinguished from noise.
A schematic diagram showing the relationship between diffraction peaks and peak intensities in an X-ray diffraction spectrum is shown in Figure 1. The X-ray diffraction spectrum is obtained by the method described in the Examples.

(Other diffraction peaks, etc.)
The glass containing the crystalline phase of the present invention may or may not have a diffraction peak at a diffraction angle 2θ of 26.60° to 27.10° (hereinafter also referred to as "range 5") in the X-ray diffraction spectrum (the diffraction intensity of the diffraction peak in range 5 is also referred to as "I ₅ ").
The glass containing a crystalline phase according to one embodiment of the present invention does not have a diffraction peak in range 5. This is expected to have the effect of providing higher transparency.
The term "having no diffraction peak" means that there is no diffraction peak having a magnitude that can be clearly distinguished from noise.
The X-ray diffraction spectra shown in FIGS. 1, 2 (Example 1), 3 (Example 9), and 4 (Comparative Example 1) are examples having no diffraction peak in range 5, and the X-ray diffraction spectra shown in FIGS. 5 to 8 (Comparative Examples 2 to 5) are examples having a diffraction peak in range 5.
The crystalline phase exhibiting a diffraction peak in range 5 is, for example, a crystalline phase derived from lithium metasilicate.

<Glass containing crystalline phase>
The glass containing a crystalline phase of the present invention is a glass material having a crystalline phase and a glass phase, and is distinguished from an amorphous material.
The glass containing a crystalline phase according to the present invention is, for example, glass-ceramics.
The glass containing a crystalline phase of the present invention can be produced by adjusting the raw material composition and production conditions according to the production method and examples described below.
Furthermore, the glass containing a crystalline phase of the present invention can have a compressive stress layer formed on the surface by various strengthening methods (chemical strengthening, thermal strengthening, ion implantation, etc.).

In one embodiment, the glass containing the crystalline phase of the present invention (e.g., crystallized glass) has a light transmittance (%) of 70% or more, 75% or more, or 80% or more at 550 nm for a sample having a thickness of 10 mm. The light transmittance (%) at 550 nm is measured by the method described in the Examples.

In one embodiment, the glass containing the crystalline phase of the present invention (e.g., crystallized glass) has an average light transmittance (%) of 70% or more, 75% or more, or 80% or more in the range of 400 to 800 nm for a sample having a thickness of 10 mm. The average light transmittance (%) in the range of 400 to 800 nm is measured by the method described in the Examples.

In one embodiment, the glass containing a crystalline phase of the present invention (e.g., crystallized glass) has an average linear expansion coefficient at 100 to 300° C. of 8×10 ⁻⁶ K ⁻¹ or less, 7×10 ⁻⁶ K ⁻¹ or less, or 5×10 ⁻⁶ K ⁻¹ or less, for example, 2×10 ⁻⁶ K ⁻¹ or more, or 3×10 ⁻⁶ K ⁻¹ or more. The average linear expansion coefficient is measured by the method described in the examples.

(Ceramics)
Glass-ceramics, also known as glass ceramics, are materials in which crystals are precipitated inside glass by heat-treating the glass. Glass-ceramics are materials that have a crystalline phase and a glass phase, and are distinguished from amorphous solids. In general, the crystalline phase of glass-ceramics is determined by the angle of the peak that appears in the X-ray diffraction pattern of X-ray diffraction analysis.

Crystalline glass can be produced by the following method. That is, the raw materials are mixed uniformly so that each component falls within a specified content range, and then melt-molded to produce raw glass. This raw glass is then crystallized to produce crystallized glass.

(raw glass)
In one embodiment, the composition of the base glass is, in mass% in terms of oxide,
The content of _SiO2 component is 65.0% to 85.0%,
The content of Al ₂ O ₃ component is 3.0% to 15.0%,
The content of _{P2O5 component} is more than 0% to 5.0%;
The content of Li ₂ O component is more than 5.0% to 15.0%;
The content of _ZrO2 component is 0% to 10.0%,
The content of the MgO component is 0% to 5.0%.
Also, in one aspect,
[Al ₂ O ₃ component content/(K ₂ O component content+MgO component content)] is more than 0 to 20.0,
The ratio of [Li ₂ O component content/MgO component content] is 6.0 or more.

In this specification, the content of each component is expressed as mass% converted to oxide unless otherwise specified. Here, "oxide equivalent" refers to the amount of oxide of each component contained in the crystallized glass expressed as mass% when it is assumed that all the crystallized glass constituent components are decomposed and converted to oxide, and the total mass of the oxide is 100 mass%. In this specification, A% to B% means A% or more and B% or less.

The base glass can be easily deformed into a curved shape by thermal processing, and in order to obtain a crystallized glass member with high light transmittance in the visible range, in addition to having the above composition, it may have the following structure.

The _SiO2 component is a framework component that constitutes glass containing a crystalline phase, and is a component for increasing stability and precipitating a desired crystalline phase. When the content of the _SiO2 component is 85.0% or less, excessive increase in viscosity and deterioration of meltability can be suppressed, and when the content is 65.0% or more, the stability of the glass containing a crystalline phase can be improved.
Therefore, the upper limit is preferably 85.0% or less, more preferably 83.0% or less, and further preferably 80.0% or less. The lower limit is preferably 65.0% or more, and may be, for example, 68.0% or more, or more than 70.0%.

The _Al2O3 component is a framework component constituting the _{inorganic composition part and is a component for enhancing stability. When the content of the Al2O3 component is} 15.0% or less, the deterioration of devitrification can be suppressed, and when the content is 3.0% or more, the deterioration of stability can be suppressed.
Therefore, the upper limit is preferably 15.0% or less, more preferably 13.0% or less, and may be, for example, less than 12.0%. The lower limit is preferably 3.0% or more, more preferably 4.0% or more, more preferably 5.0% or more, more preferably more than 7.0%, and more preferably more than 8.0%.

The P ₂ O ₅ component is an essential component that promotes the crystal formation of glass containing a crystalline phase. When the content of the P ₂ O ₅ component is 5.0% or less, phase separation of the glass can be suppressed.
Therefore, the upper limit is preferably set to 5.0% or less, more preferably 4.5% or less, and even more preferably 4.0% or less. The lower limit is preferably set to more than 0%, more preferably 0.5% or more, and even more preferably 1.0% or more.
The content of the _P2O5 component may be 3.0% or less, 2.7% _or less, or 2.5% or less. Also, the content of _{the P2O5 component} may be 1.5% or more, or 2.0% or more.

The Li ₂ O component is a component that improves the meltability of the base glass and enhances manufacturability. When the content of the Li ₂ O component is 15.0% or less, the deterioration of devitrification can be suppressed, and when it exceeds 5.0%, the deterioration of viscosity and meltability can be suppressed, and manufacturability can be improved.
Therefore, the lower limit is preferably more than 5.0%, more preferably 6.0% or more, and even more preferably 7.0% or more. The upper limit is preferably 15.0% or less, more preferably 13.0% or less, and may be, for example, 12.0% or less.

Although the glass containing the crystalline phase according to the present invention can be produced even with 0% ZrO2, it is a component that acts as a nucleating agent for crystals when contained in an amount exceeding 0%. When the content of _{the ZrO2 component} is 10.0% or less, deterioration of meltability can be suppressed.
Therefore, the upper limit is preferably 10.0% or less, more preferably 8.0% or less, more preferably 5.0% or less, and even more preferably 4.0% or less. It may also be 3.0% or less, 2.5% or less, or less than 2.5%. The lower limit is preferably 0% or more, more preferably 0.3% or more, and even more preferably 0.5% or more. It may also be 0.8% or more, 1.0% or more, or more than 1.5%.

Although the glass containing the crystal phase according to the present invention can be produced even with 0% MgO, the glass is a component that improves low-temperature melting property when it is contained in an amount of more than 0%. When the content of the MgO component is 5.0% or less, the glass is easily strengthened when chemically strengthened.
Therefore, the upper limit can be preferably set to 5.0% or less, more preferably 3.0% or less, and even more preferably less than 2.0%. The lower limit can be preferably set to 0% or more, more preferably 0.1% or more, and even more preferably 0.2% or more.

Although the ZnO component can produce a glass containing the crystal phase according to the present invention even at 0%, it is a component that improves low-temperature melting property when contained at more than 0%. When the ZnO content is 5.0% or less, the glass is easily strengthened when chemically strengthened.
Therefore, the upper limit can be preferably set to 5.0% or less, more preferably 3.0% or less, and even more preferably less than 2.0%. The lower limit can be preferably set to 0% or more, more preferably more than 0%, more preferably 0.1% or more, and even more preferably 0.2% or more.

Although the CaO component can produce a glass containing the crystalline phase according to the present invention even at 0%, it is a component that improves low-temperature melting property when contained at more than 0%. When the CaO content is 5.0% or less, the glass is easily strengthened when chemically strengthened.
Therefore, the upper limit can be preferably set to 5.0% or less, more preferably 3.0% or less, and further preferably less than 1.0%.

Although the glass according to the present invention can be produced even with 0% of each of the SrO component and the BaO component, these components improve low-temperature melting property when contained in an amount exceeding 0%. When the content of each of the SrO component and the BaO component is 5.0% or less, the glass is easily strengthened when chemically strengthened.
Therefore, the upper limit of each of the SrO component and the BaO component can be preferably set to 5.0% or less, more preferably 3.0% or less, and further preferably 1.0% or less.

The _glass according to the present invention can be produced even with 0% _Gd2O3 , but when it is contained in an amount exceeding 0%, it is a component that can increase the refractive index and reduce the partial dispersion ratio. On the other hand, if a large amount of _Gd2O3 is contained, the _liquidus temperature decreases, and there is a risk of devitrifying the glass. By making _{the Gd2O3 component} 10.0% or less, it is possible to reduce devitrification and coloring.
Therefore, the upper limit of the content of the Gd ₂ O ₃ component is preferably 10.0% or less, more preferably 8.0% or less, further preferably 5.0% or less, and most preferably 3.0% or less.

By setting the total content of the CaO component and the MgO component [CaO component content + MgO component content] to 5.0% or less, it is possible to prevent chemical strengthening from becoming difficult, and even at 0% it is possible to produce glass containing the crystalline phase according to the present invention. However, when the content exceeds 0%, it is possible to prevent deterioration of meltability.
Therefore, the upper limit of [CaO component content + MgO component content] is preferably 5.0% or less, more preferably 3.0% or less, more preferably less than 3.0%, and further preferably 1.0% or less.
The lower limit of [CaO content + MgO content] is preferably 0% or more, more preferably more than 0%, more preferably 0.1% or more, and further preferably 0.2% or more.

The K ₂ O component and the Na ₂ O component are components that improve the meltability of the raw glass and enhance manufacturability. When the content of each of the K ₂ O component and the Na ₂ O component is 5.0% or less, the deterioration of devitrification can be suppressed. In addition, even if the content of each of the K ₂ O component and the Na _{2 O component is 0%, the glass containing the crystal phase according to the present invention can be produced, but when the content of each of the K 2 O component and the Na 2} O component exceeds 0%, the deterioration of viscosity and meltability can be suppressed and the manufacturability can be improved.
Therefore, the lower limit of each of the _K2O component and the _Na2O component is preferably 0% or more, more preferably 0.2% or more, and even more preferably 0.3% or more. The upper limit of each of the _K2O component and the _Na2O component is preferably 5.0% or less, more preferably 4.0% or less, more preferably less than 3.0%, and even more preferably less than 2.0%.

Sb ₂ O ₃ component is a component that functions as a clarifier when manufacturing raw glass. If Sb ₂ O ₃ component is contained in excess, the transmittance in the short wavelength region of the visible light region may be deteriorated. Therefore, the upper limit can be preferably 2.0% or less, more preferably 1.0% or less, more preferably 0.6% or less, and even more preferably 0.5% or less.
Also, the lower limit can be preferably set to 0% or more, more preferably more than 0%, more preferably 0.001% or more, more preferably 0.01% or more, and more preferably 0.05% or more.

_{The B2O3} component has the effect of lowering the viscosity of the base glass. When the content of _{the B2O3} component is 10.0% or less, the deterioration of devitrification can be suppressed. In addition, even if the content of _{the B2O3} component is 0%, the glass containing the crystal phase according to the present invention can be produced, but when the content exceeds 0%, the deterioration of the viscosity and meltability of the base glass can be suppressed.
Therefore, the upper limit can be preferably set to 10.0% or less, more preferably 8.0% or less, more preferably 7.0% or less, more preferably 5.0% or less, more preferably 4.0% or less, and even more preferably 3.0% or less.
Also, the lower limit can be preferably 0% or more, more preferably more than 0%, more preferably 0.001% or more, more preferably 0.01% or more, more preferably 0.05% or more, more preferably 0.10% or more, and even more preferably 0.30% or more.

Although the glass containing the crystal phase according to the present invention can be produced even when the total content of K ₂ O and Na ₂ O [K ₂ O content + Na ₂ O content] is 0%, when it exceeds 0%, deterioration of viscosity can be suppressed and an increase in melting temperature can be suppressed. In addition, by making the content 5.0% or less, deterioration of devitrification can be suppressed.
Therefore, the lower limit of [K ₂ O content + Na ₂ O content] is preferably 0% or more, more preferably 0.1% or more, more preferably 0.2% or more, and even more preferably 0.3% or more. The upper limit is preferably 5.0% or less, more preferably 4.0% or less, more preferably less than 4.0%, more preferably less than 3.0%, and even more preferably less than 2.0%.

The total content of MgO, CaO, SrO, BaO and ZnO [MgO + CaO + SrO + BaO + ZnO] is 15.0% or less to facilitate chemical strengthening. Even if [MgO + CaO + SrO + BaO + ZnO] is 0%, the glass containing the crystalline phase according to the present invention can be produced, but if it is more than 0%, deterioration of meltability can be suppressed.
Therefore, the lower limit of [MgO component + CaO component + SrO component + BaO component + ZnO component] is preferably 0% or more, more preferably more than 0%, more preferably 0.5% or more, and may be 1.0% or more. Also, the upper limit is preferably 15.0% or less, more preferably 10.0% or less, more preferably 5.0% or less, and even more preferably 3.5% or less.

By setting the ratio [Al ₂ O ₃ content/K ₂ O content] to 100.0 or less, it is possible to suppress the deterioration of viscosity, and by setting it to 0.6 or more, it is possible to suppress the deterioration of devitrification.
Therefore, the upper limit of [Al ₂ O ₃ component content/K ₂ O component content] is preferably 100.0 or less, more preferably 80.0 or less, more preferably 60.0 or less, more preferably 40.0 or less, more preferably 20.0 or less, and even more preferably 15.0 or less.
The lower limit of the ratio of the content of the Al ₂ O ₃ component to the content of the K ₂ O component is preferably 0.6 or more, more preferably 1.0 or more, more preferably 2.0 or more, more preferably 3.0 or more, and even more preferably 5.7 or more. The content of the K ₂ O component can be 0.

When the ratio [Al ₂ O ₃ content/(K ₂ O content+MgO content)] is 20.0 or less, the deterioration of viscosity can be suppressed. When the ratio is more than 0, the deterioration of devitrification can be suppressed.
Therefore, the upper limit is preferably 20.0 or less, more preferably 18.0 or less, more preferably 16.0 or less, and even more preferably 15.0 or less.
The lower limit of [Al ₂ O ₃ component content/(K ₂ O component content+MgO component content)] is preferably more than 0, more preferably 1.0 or more, more preferably 2.0 or more, and even more preferably 2.6 or more.

By setting [Al ₂ O ₃ component content/(ZnO component content+MgO component content)] to 20.0 or less, deterioration of meltability can be suppressed, and by setting it to 3.0 or more, deterioration of devitrification can be suppressed.
Therefore, the upper limit of [ _Al2O3 content/( _ZnO content+MgO content)] is preferably 20.0 or less, more preferably 18.0 or less, and even more preferably 17.0 or less, and may be 16.0 or less. The lower limit is preferably 3.0 or more, more preferably 4.0 or more, and may be more than 5.0.

By making the ratio [Li ₂ O component content/MgO component content] 150.0 or less, it is possible to suppress deterioration of devitrification, and by making it 6.0 or more, it is possible to facilitate chemical strengthening.
Therefore, the upper limit of the [Li ₂ O content/MgO content] is preferably 150.0 or less, more preferably 100.0 or less, more preferably 50.0 or less, more preferably 30.0 or less, and may be 25.0 or less, or 23.0 or less. Also, MgO may be 0.
On the other hand, a preferable lower limit of [Li ₂ O component content/MgO component content] is 6.0 or more, and may be 7.0 or more, 8.0 or more, 9.0 or more, 9.5 or more, 10.0 or more, or 10.6 or more.

By making the ratio [ _Li2O content/(MgO content+CaO content+SrO content+BaO content+ _Na2O content+ _K2O content)] 50.0 or less, the melting property can be improved and the deterioration of devitrification can be suppressed. Also, by making it 1.0 or more, it is possible to suppress the difficulty of chemical strengthening.
Therefore, the preferred upper limit of [Li ₂ O component content/(MgO component content+CaO component content+SrO component content+BaO component content+Na ₂ O component content+K ₂ O component content)] is 50.0 or less, more preferably 35.0 or less, more preferably 30.0 or less, more preferably 20.0 or less, more preferably 15.0 or less, more preferably 13.0 or less, and even more preferably 10.0 or less.
In addition, the ratio of [Li ₂ O component content/(MgO component content+CaO component content+SrO component content+BaO component content+Na ₂ O component content+K ₂ O component content)] may be zero.
On the other hand, the preferable lower limit of [Li ₂ O component content/(MgO component content+CaO component content+SrO component content+BaO component content+Na ₂ O component content+K ₂ O component content)] can be 1.0 or more, more preferably 2.0 or more, more preferably 3.0 or more, and even more preferably more than 3.0.

By setting [MgO component content/(Li ₂ O component content+MgO component content)] to 0.6 or less, it is possible to prevent chemical strengthening from becoming difficult and to prevent devitrification from worsening. Even if the lower limit is 0, a glass containing the crystalline phase according to the present invention can be produced. However, by setting it to more than 0, it is possible to improve low-temperature melting property while maintaining devitrification.
Therefore, the upper limit of [content of MgO component/(content of Li ₂ O component+content of MgO component)] is preferably 0.6 or less, more preferably 0.3 or less, and further preferably less than 0.15.
On the other hand, the lower limit of [MgO component content/(Li ₂ O component content+MgO component content)] is preferably 0 or more, more preferably 0.01 or more, more preferably 0.03 or more, and even more preferably 0.04 or more.

The total content of _Li2O , _Na2O , and _K2O [ _Li2O content + _Na2O content + _K2O content] is an index of the ease of making a base glass by improving the melting property. That is, by making it 17.0% or less, it is possible to suppress the deterioration of devitrification, and by making it 3.0% or more, it is possible to suppress the deterioration of viscosity and the increase of melting temperature.
Therefore, the upper limit of [Li ₂ O component content + Na ₂ O component content + K ₂ O component content] is preferably 17.0% or less, more preferably 15.0% or less, and further preferably 14.0% or less.
The lower limit of [Li ₂ O component content + Na ₂ O component content + K ₂ O component content] is preferably 3.0% or more, more preferably 5.0% or more, and further preferably 8.0% or more.

When the total content of the _Li2O component and _{the P2O5 component} [ _Li2O component content + _P2O5 component content] is 18.0% or less, the deterioration of devitrification can be suppressed. In addition, [ _Li2O component content + _{P2O5 component} content] is, for example _, 8.0% or more.
Therefore, the upper limit of [Li ₂ O component content + P ₂ O ₅ component content] is preferably 18.0% or less, more preferably 17.0% or less, and may be, for example, 15.0% or less, 14.0% or less, or 13.8% or less.
The lower limit of [Li ₂ O component content + P ₂ O ₅ component content] is preferably 8.0% or more, more preferably 9.0% or more, more preferably 10.0% or more, more preferably 11.5% or more, and even more preferably 12.01% or more.

_{When the total content of Li2O, P2O5 and Al2O3 [ Li2O content + P2O5 content} + _Al2O3 content] is 40.0% or _less , the deterioration of devitrification can be suppressed. Also, when [ _Li2O content + _P2O5 content + _Al2O3 content] is 21.5% or more _, the effect _of promoting the precipitation of _fine crystals is expected.
Therefore, the upper limit of [the content of the _Li2O component + the content of _{the P2O5} component + the content of _{the Al2O3} component] is preferably 40.0% or less, more preferably 35.0% or less, and may be 27.5% or less, 25.0% or less, 24.5% or less, 24.0% or less, 23.8% or less, or 23.5% or less.
In addition, the preferable lower limit of [ _Li2O component content + _P2O5 component content + _{Al2O3 component} content] is 21.5% or more, more preferably 21.8% _or more, more preferably 22.0% or more, more preferably 22.5% or more, and may be 22.8% or more.

When the ratio of [P ₂ O ₅ content/MgO content] is 50.0 or less, the deterioration of low-temperature melting property can be suppressed. Also, the ratio of [P ₂ O ₅ content/MgO content] is, for example, more than 0.
Therefore, the upper limit of the ratio of _{the P2O5} component content to the MgO component content is preferably 50.0 or less, more preferably 30.0 or less, more preferably 10.0 or less, more preferably 7.0 or less, and may be 5.0 or less, 4.1 or less, 4.0 or less, or 3.7 or less. Also, the content of the MgO component may be 0.
In addition, the lower limit of [ _{P2O5 component} content/MgO component content] is preferably more than 0, more preferably 0.02 or more, more preferably 0.1 or more, more preferably 0.15 or more, and even more preferably 1.0 or more, and may be 1.5 or more, or 2.4 or more.

The ratio [ _SiO2 component content/ _ZrO2 component content] is, for example, 150.0 or less, and by making it 10.0 or more, deterioration of devitrification can be suppressed.
Therefore, the preferable upper limit of [ _SiO2 component content/ _ZrO2 component content] is 150.0 or less, and may be 100.0 or less, 50.0 or less, 40.0 or less, 37.0 or less, 35.4 or less, 35.0 or less, 33.7 or less, or 32.7 or less.
Further, the preferable lower limit of [ _SiO2 component content/ _ZrO2 component content] is 10.0 or more, and may be 13.0 or more, 15.0 or more, 17.0 or more, 18.0 or more, 19.6 or more, or 29.9 or more.

By setting the ratio of [ _SiO2 component content/ _Li2O component content] to 17.0 or less, deterioration of low-temperature melting property can be suppressed. Also, the ratio of [ _SiO2 component content/ _Li2O component content] is, for example, 4.0 or more.
Therefore, the upper limit of [ _SiO2 component content/ _Li2O component content] is preferably 17.0 or less, more preferably 15.0 or less, more preferably 13.0 or less, more preferably 10.0 or less, more preferably 9.0 or less, and even more preferably 7.6 or less.
The lower limit of the ratio [ _SiO2 component content/ _Li2O component content] is preferably 4.0 or more, more preferably 4.3 or more, and further preferably 5.0 or more.

The ratio [ _SiO2 component content/ _{P2O5 component} content] is, for example, 100.0 or less, and by making it 13.0 or more, it is possible to suppress the deterioration of devitrification.
Therefore, the upper limit of [ _SiO2 component content/ _{P2O5 component} content] is preferably 100.0 or less, more preferably 80.0 or less, more preferably 50.0 or less, more preferably 40.0 or less, and even more preferably 39.0 or less.
The lower limit of the ratio of the _SiO2 component content to _{the P2O5} component content is preferably 13.0 or more, more preferably 17.0 or more, and even more preferably 20.0 or more. It may also be 25.0 or more, 30.0 or more, or 33.0 or more.

The ratio [content of _SiO2 component/(content of _P2O5 component+content of _ZrO2 component)] is, for example, 100.0 or less, and by making it 4.3 or more _, it is possible to suppress the deterioration of devitrification.
Therefore, the upper limit of [content of _SiO2 component/(content of _{P2O5 component} +content of _ZrO2 component)] is preferably 100.0 or less, more preferably 80.0 or less, more preferably 50.0 or less, more preferably 42.5 or less, more preferably 35.0 or less, and may be 30.0 or less, 25.0 or less, 20.0 or less, or 17.99 or less.
The lower limit of the _ratio (content of _SiO2 component/(content of _P2O5 component+content of _ZrO2 component)) is preferably 4.3 or more, more preferably 10.0 or more. It may also be 13.0 or more, 15.0 or more, or 16.1 or more.

The ratio of [ _SiO2 content/( _Na2O content+ _K2O content)] to 120.0 or less can suppress deterioration of low-temperature melting property. In addition, the ratio of [ _SiO2 content/( _Na2O content+ _K2O content)] is, for example, 23.0 or more.
Therefore, the upper limit of [ _SiO2 component content/( _Na2O component content+ _K2O component content)] is preferably 120.0 or less, more preferably 110.0 or less, preferably 100.0 or less (or less than 100.0), more preferably 90.0% or less, and even more preferably 80.0% or less.
Further, the lower limit of [ _SiO2 component content/( _Na2O component content+ _K2O component content)] is preferably 23.0 or more, more preferably 25.0 or more, more preferably 30.0 or more, more preferably 35.0 or more, and may be 54.0 or more.

[Content of ZnO component/(content of Li ₂ O component+content of P ₂ O ₅ component+content of MgO component)] is, for example, 1.0 or less. Even if the lower limit is 0, a glass containing a crystalline phase according to the present invention can be produced. However, by making it exceed 0, it is possible to improve low-temperature melting property while maintaining devitrification property.
Therefore, the upper limit of [ZnO component content/(Li ₂ O component content+P ₂ O ₅ component content+MgO component content)] is preferably 1.0 or less, more preferably 0.09 or less, more preferably less than 0.06, and further preferably 0.05 or less.
In addition, the lower limit of [ZnO component content/(Li ₂ O component content+P ₂ O ₅ component content+MgO component content)] is preferably 0 or more, more preferably more than 0, more preferably 0.01 or more, more preferably 0.02 or more, and even more preferably 0.03 or more.

_When [(content of _SiO2 component + content of _Al2O3 component + content of _{P2O5 component} )/(content of _Li2O component + content of _Na2O component + content of _K2O component + content of MgO component)] is set to 9.0 or less, deterioration of low-temperature melting property can be suppressed, and when it is set to 0.7 or more, crystal precipitation can be promoted.
Therefore, the _upper limit of [( _SiO2 component content + _Al2O3 component content + _{P2O5 component} content)/( _Li2O component content + _Na2O component content + _K2O component content + MgO component content)] is preferably 9.0 or less, more preferably 8.0 or less, more preferably 7.5 or less, and even more preferably less than 7.25.
In addition, the preferable _lower limit of [( _SiO2 component content + _Al2O3 component content + _{P2O5 component} content)/( _Li2O component content + _Na2O component content + _K2O component content + MgO component content)] is 0.7 or more, more preferably 4.0 or more, more preferably 5.0 or more, and may be 6.0 or more.

The glass containing _the crystalline phase of the present invention may _or may not contain _TiO2 , _{Bi2O3 , Cr2O3} , _CuO , _La2O3 , MnO, _MoO3 , PbO, _V2O5 , _WO3 , and _Y2O3 components, as long as the effect of the present invention is not impaired. Not containing _these components has the effect of preventing the transmittance from deteriorating.

Furthermore, the crystallized glass may or may not contain other components not mentioned above, as long as they do not impair the properties of the crystallized glass of the present invention. For example, metal components such as Yb, Lu, Fe, Co, Ni, and Ag (including oxides of these metals), etc.

Further, as a fining agent for glass, in addition to _{Sb2O3 , SnO2} , CeO2, _As2O3 , and one or _more selected from the group consisting of F, _NOx , and SOx may or may not be included. However, the upper limit of the content of the fining agent can be preferably set to 3.0% or less, more preferably 2.0% or less, more preferably 1.0% or less, and most preferably 0.6% or less.

On the other hand, in recent years, there has been a trend to reduce the use of Pb, Th, Tl, Os, Be, Cl, and Se as harmful chemical substances, so it is preferable that these components are substantially free of these. "Substantially free of" refers to cases where these components are contained as unavoidable impurities or are not contained at all. The total amount of these components is, for example, 0.1% or less.

(Method for producing crystallized glass)
The heat treatment for crystal precipitation may be a one-stage or two-stage heat treatment.
In the two-stage heat treatment, a nucleation step is first performed by heat treatment at a first temperature, and after this nucleation step, a crystal growth step is performed by heat treatment at a second temperature higher than that of the nucleation step.
The first temperature of the two-stage heat treatment is preferably 400° C. to 750° C., more preferably 450° C. to 720° C., and even more preferably 500° C. to 680° C. It may also be 550° C. to 650° C. The holding time at the first temperature is preferably 30 minutes to 2000 minutes, and more preferably 180 minutes to 1440 minutes.
The second temperature of the two-stage heat treatment is preferably 550° C. to 850° C., and more preferably 600° C. to 800° C. It can also be 650° C. to 750° C. The holding time at the second temperature is preferably 30 minutes to 600 minutes, and more preferably 60 minutes to 400 minutes.

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

Examples 1 to 68, Comparative Examples 1 to 5
(1) Preparation of Raw Materials As raw materials for each component of the crystallized glass, raw materials of the corresponding oxides were selected, and these raw materials were weighed out so as to obtain the compositions shown in Tables 1 to 4, and mixed uniformly.

(2) Manufacturing of crystallized glass The mixed raw materials were then placed in a platinum crucible and melted in an electric furnace at 1300°C to 1600°C for 2 to 24 hours depending on the degree of melting difficulty of the glass composition. The molten glass was then stirred to homogenize it, and the temperature was lowered to 1000°C to 1450°C before it was poured into a mold and slowly cooled to produce the original glass.
The obtained raw glass was heated under the nucleation conditions and crystallization (nucleus growth) conditions shown in Tables 5 to 8 to prepare crystallized glass. In Tables 5 to 8, "-" indicates that the corresponding step was not performed.

(3) X-ray diffraction (XRD) measurement The crystallized glass obtained in (2) was cut and processed to obtain a plate-shaped measurement sample having a thickness of 5 mm. The measurement sample was analyzed by X-ray diffraction method using CuKα radiation in the range of 2θ = 15 to 30 ° at intervals of 0.02 ° using an automatic X-ray diffractometer (Bruker "D8 DISCOVER") in accordance with JIS K0131 (1996). The X-ray diffraction spectrum was obtained by removing the background specific to the device from the obtained diffraction pattern. The "background specific to the device" is a diffraction pattern obtained by measurement under the same conditions without using a measurement sample.

_I1 to _I5 in the X-ray diffraction spectrum are shown in Tables 5 to 8. In Tables 5 to 8, "-" indicates that the corresponding peak was not present. Examples in which all of _I1 to _I5 are "-" indicate that X-ray diffraction analysis was not performed.
Moreover, "(I ₃ +I ₄ )/(I ₁ +I ₂ )" calculated from I ₁ to I ₄ above is shown in Tables 5 to 8.
The X-ray diffraction spectrum obtained in Example 1 is shown in Figure 2, the X-ray diffraction spectrum obtained in Example 9 is shown in Figure 3, and the X-ray diffraction spectra obtained in Comparative Examples 1 to 5 are shown in Figures 4 to 8, respectively. In the X-ray diffraction spectra, the vertical axis represents intensity (count number, unitless) and the horizontal axis represents 2θ.
In all examples where X-ray diffraction analysis was performed, a crystalline phase derived from lithium disilicate, a crystalline phase derived from petalite, a crystalline phase derived from β-quartz solid solution, and a crystalline phase derived from vergilite were confirmed, but no crystalline phase derived from lithium metasilicate was confirmed.

(4) Measurement of light transmittance The crystallized glass obtained in (2) was polished to obtain a plate-shaped measurement sample having a thickness of 10 mm. The measurement sample was measured for light transmittance (%) at 550 nm and average light transmittance (%) at 400 to 800 nm using a spectrophotometer (Hitachi High-Technologies Corporation's "U-4000"). The results are shown in Tables 5 to 8. "-" indicates that the measurement was not performed.

(5) Measurement of average linear expansion coefficient The average linear expansion coefficient of the crystallized glass obtained in Example 3(2) was measured at 100 to 300 ° C. in accordance with the Japan Optical Glass Industry Association standard JOGIS08-2019 "Method of measuring thermal expansion of optical glass."
The average linear expansion coefficient was 47×10 ⁻⁷ K ⁻¹ .

From Tables 5 to 8, it can be seen that all examples in which (I ₃ +I ₄ )/(I ₁ +I ₂ ) is confirmed to be 1.60 or more have excellent light transmittance. In Examples 35, 38, and 41 to 51, glass crystallization is not performed, but with the raw glass composition of these examples, by appropriately adjusting the conditions for crystallization while referring to other examples, it is possible to produce crystallized glass that satisfies formula (1) and exhibits high transparency.

Although some embodiments and/or examples of the present invention have been described in detail above, those skilled in the art can easily make many modifications to these exemplary embodiments and/or examples without substantially departing from the novel teachings and advantages of the present invention, and therefore many such modifications are within the scope of the present invention.
The contents of all documents cited in this specification and of the application from which this application claims priority under the Paris Convention are incorporated by reference in their entirety.

Claims (10)

In the X-ray diffraction spectrum obtained by the X-ray diffraction method,
The diffraction intensity of the diffraction peak at the diffraction angle 2θ=23.50° to 24.00° is represented as I ₁ ,
The diffraction intensity of the diffraction peak at the diffraction angle 2θ of 24.05° to 24.55° is represented as I ₂ ,
The diffraction intensity of the diffraction peaks at the diffraction angle 2θ of 24.60° to 25.05° is represented as I ₃ ,
When the diffraction intensity of the diffraction peak existing at the diffraction angle 2θ=25.20° to 26.60° is defined as _I4 ,
( _I3 + _I4 )/( _I1 + _I2 ) is 1.60 or more;
Glass containing crystalline phases. 2. The glass containing crystalline phases according to claim 1, wherein ( _I3 + _I4 )/( _I1 + _I2 ) is 4.50 or less. 3. A glass comprising a crystalline phase according to claim 1 or 2, wherein _I4 is greater than _I3 . 3. A glass comprising a crystalline phase according to claim 1 or 2, wherein _I1 is greater than _I2 . 3. A glass comprising a crystalline phase according to claim 1 or 2, wherein _I3 is greater than _I1 . 3. A glass comprising a crystalline phase according to claim 1 or 2, wherein _I3 is greater than _I2 . 3. The glass containing a crystalline phase according to claim 1, wherein _I4 is the maximum among _I1 to _I4 . Glass containing the crystalline phase according to claim 1 or 2, which does not have a diffraction peak at a diffraction angle 2θ of 26.60° to 27.10° in the X-ray diffraction spectrum. Glass containing the crystalline phase according to claim 1 or 2, which is a crystallized glass. The composition of the raw glass is expressed as mass% in terms of oxides,
_SiO2 content 65.0% to 85.0%,
Al ₂ O ₃ content: 3.0% to 15.0%;
_{P2O5 component} content: more than 0% to 5.0%;
Li ₂ O content: more than 5.0% to 15.0%;
_ZrO2 content: 0% to 10.0%;
MgO content: 0% to 5.0%
3. A glass comprising the crystalline phase according to claim 1 or 2,

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