Glass and crystallized glass

Abstract

The present invention relates to a glass containing, in terms of mole percent on an oxide basis, 63-72% of SiO2, 12.0-19.0% of Al2O3, 9-13% of Li2O, 0.1-2% of K2O, and 0-1% of TiO2. The ratio Li2O / Al2O3 of the Li2O content and the Al2O3 content is 0.50-0.88.

Description

Glass and glass-ceramics

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

[0002] Cover glass for mobile devices and the like are required to have strength and transparency. Known methods for increasing strength include chemical strengthening, which applies compressive stress to the glass surface, thereby increasing resistance to cracking due to external forces, or so-called bending strength. Crystallized glass, in which crystals are precipitated in glass, is known to be harder and more scratch-resistant than amorphous glass, which does not contain crystals. Meanwhile, crystallized glass has room for improvement in terms of transparency compared to amorphous glass.

[0003] Patent Document 1 describes a transparent crystallized glass.

[0004] Japanese Patent Publication No. 64-52631

[0005] However, even among transparent crystallized glasses, few have high enough transparency to be suitable for use as cover glass. Furthermore, the crystallized glass described in Patent Document 1 is not chemically strengthened, and therefore is insufficient in strength for use as cover glass. The chemical strengthening properties of crystallized glasses are strongly influenced by the glass composition and precipitated crystals. Furthermore, the scratch resistance and transparency of crystallized glasses are also strongly influenced by the glass composition and precipitated crystals.

[0006] Furthermore, known manufacturing methods for mass-producing glass include the float method, roll-out method, fusion method, and down-draw method. In any of these methods, the relationship between the viscosity and devitrification temperature of the glass is important, and the glass must have physical properties suitable for each method.

[0007] In order to obtain glass that can be used by a float method or the like to obtain glass-ceramics that are excellent in both chemical strengthening properties and transparency, delicate adjustment of the glass composition and precipitated crystals is required. The present invention aims to provide glass that can be used to obtain glass-ceramics that are excellent in transparency and chemical strengthening properties. The present invention also aims to provide glass-ceramics that are excellent in transparency and chemical strengthening properties.

[0008] The present invention relates to a glass having the following composition, expressed in mole percent on an oxide basis: SiO ２ 63 to 72%, Al ２ O ３ 12.0-19.0%, Li ２ O 9-13%, K ２ 0.1-2% O, TiO ２ Contains 0 to 1% of Li ２ O content and Al ２ O ３ Content ratio Li ２ O / Al ２ O ３ A glass having a viscosity of 0.50 to 0.88.

[0009] The present invention also relates to the following glass-ceramics, wherein the mother glass contains, in mole percent on an oxide basis, SiO ２ 63 to 72%, Al ２ O ３ 12.0-19.0%, Li ２ O 9-13%, K ２ 0.1-2% O, TiO ２ Contains 0 to 1% of Li ２ O content and Al ２ O ３ Content ratio Li ２ O / Al ２ O ３ is 0.50 to 0.88.

[0010] According to the present invention, glass is provided that can be used to obtain crystallized glass having excellent transparency and chemical strengthening properties.Furthermore, according to the present invention, crystallized glass having excellent transparency and chemical strengthening properties can be obtained.

[0011] 1 shows a schematic diagram of a glass manufacturing apparatus using a float process. ２ 3 is a schematic diagram showing the relationship between the fracture toughness value K ＩＣ 4 is an explanatory diagram of a sample used for measuring the fracture toughness value K by the DCDC method. ＩＣ The stress intensity factor K1 (unit: MPa m １／２1 is a graph showing a K1-v curve showing the relationship between the crack propagation velocity v (unit: m / s) and the crack propagation velocity v (unit: m / s).

[0012] In this specification, unless otherwise specified, the term "to" indicating a range of values ​​is used to mean that the values ​​before and after it are included as the lower and upper limits.

[0013] In this specification, "amorphous glass" refers to glass in which no diffraction peaks indicating crystals are observed by the powder X-ray diffraction method described below. Also, "crystallized glass" is obtained by heat-treating "amorphous glass" to precipitate crystals, and contains crystals. Also, amorphous glass that becomes crystallized glass by heat treatment is sometimes called "mother glass of crystallized glass." In this specification, when "glass" is referred to, it means "amorphous glass."

[0014] In this specification, powder X-ray diffraction measurement is performed using, for example, CuKα radiation in the 2θ range of 10° to 80°, and if a diffraction peak appears, the precipitated crystals are identified by the Hanawalt method. Furthermore, among the crystals identified by this method, the crystal identified from the peak group containing the peak with the highest integrated intensity is considered to be the main crystal. As a powder X-ray diffraction measurement device, for example, a SmartLab manufactured by Rigaku Corporation can be used.

[0015] In this specification, "chemically strengthened glass" refers to glass after chemical strengthening treatment, and "glass for chemical strengthening" refers to glass before chemical strengthening treatment. Also, "mother composition of chemically strengthened glass" refers to the glass composition of the glass for chemical strengthening.

[0016] In this specification, unless otherwise specified, glass compositions are expressed in mol % on an oxide basis, and mol % is simply expressed as "%".

[0017] In this specification, "substantially free from" means that it is not intentionally added, but it may be contained as an impurity due to raw materials, machinery, equipment, etc. Specific examples of impurities will be described later.

[0018] In this specification, the term "stress profile" refers to a representation of compressive stress values ​​with depth from the glass surface as a variable. In the stress profile, tensile stress is represented as negative compressive stress.

[0019] The "compressive stress value (CS)" can be measured by slicing a cross section of glass and analyzing the sliced ​​sample with a birefringence imaging system. A birefringence imaging system birefringence stress meter is a device that measures the magnitude of retardation caused by stress using a polarizing microscope and a liquid crystal compensator, etc., and an example of such a device is the birefringence imaging system Abrio-IM manufactured by CRi.

[0020] In addition, in order to non-destructively obtain the stress value of chemically strengthened glass, for example, a scattered light photoelastic stress meter SLP-2000 manufactured by Orihara Seisakusho or a glass surface stress meter FSM6000-LEUV can be used in combination.

[0021] In the method using a scattered light photoelastic stress meter (SLP), compressive stress resulting from Li—Na exchange can be measured inside the glass at a depth of several tens of μm or more from the glass surface.

[0022] On the other hand, in the method using a glass surface stress meter (FSM), the compressive stress resulting from Na—K exchange can be measured in the glass surface layer within a depth of several tens of μm from the glass surface.

[0023] In this specification, the "depth of compressive stress (DOL)" is the depth at which the compressive stress value becomes zero. Hereinafter, the surface compressive stress value is referred to as CS ０ , the compressive stress value at a depth of 50 μm is CS ５０ , and "internal tensile stress (CT)" refers to the tensile stress value at a depth of 1 / 2 of the plate thickness t.

[0024] <Glass> The glass according to an embodiment of the present invention (hereinafter also referred to as the present glass) contains, in terms of mole percentage based on oxides, SiO ２ 63 to 72%, Al ２ O ３ 12.0-19.0%, Li ２ O 9-13%, K ２ 0.1-2% O, TiO ２Contains 0 to 1% of Li ２ O content and Al ２ O ３ Content ratio Li ２ O / Al ２ O ３ is 0.50 to 0.88.

[0025] The present glass having the above composition can provide crystallized glass that is excellent in both chemical strengthening properties and transparency. In particular, crystallized glass containing β-spodumene as precipitated crystals can be easily obtained. Crystallized glass containing β-spodumene has excellent chemical strengthening properties. β-spodumene is a LiAlSi ２ O ６ and is generally a crystal that exhibits diffraction peaks at Bragg angles (2θ) of 25.55°±0.05°, 22.71°±0.05°, and 28.20°±0.05° in an X-ray diffraction spectrum. However, by using the Rietveld method, it is possible to confirm the precipitation of β-spodumene from the X-ray diffraction spectrum even when the crystal structure is distorted.

[0026] As mentioned above, crystallized glass containing β-spodumene has excellent chemical strengthening properties. Here, amorphous glass in which β-spodumene can precipitate may precipitate β-quartz solid solution depending on the heat treatment conditions, etc. β-quartz solid solution is also called virgilite or keatite, and like β-spodumene, it contains LiAlSi ２ O ６ However, its crystal structure differs from that of β-spodumene. β-spodumene and β-quartz solid solution also differ in their chemical strengthening properties. Glass-ceramics containing β-spodumene are prone to increased surface compressive stress due to chemical strengthening. β-spodumene has a denser crystal structure than β-quartz solid solution, so when ions in the precipitated crystals are replaced with larger ions through ion exchange treatment for chemical strengthening, high compressive stress is generated, which is thought to enhance the effects of chemical strengthening.

[0027] β-Spodumene is known to have a high crystal growth rate. Therefore, crystals in glass-ceramics containing β-spodumene generally tend to grow large, which often results in low transparency and a high haze value. However, the present glass-ceramics obtained by crystallizing the present glass having the above composition contains many minute crystals, so even if the crystallization rate is high, the present glass-ceramics has high transparency and a low haze value.

[0028] Furthermore, the present glass having the above composition has viscosity and devitrification characteristics suitable for processes such as the float method, roll-out method, fusion method, and down-draw method, particularly the float method. Therefore, the present glass can be easily produced by the float method, and by heat-treating the obtained present glass, crystallized glass with excellent chemical strengthening properties and transparency can be obtained.

[0029] The glass composition of the present glass will be described below. ２ is a component that forms the network structure of glass. It is also a component that increases chemical durability and is a constituent of β-spodumene, which is a precipitated crystal. SiO ２ The content of SiO is 63% or more, preferably 63.5% or more, more preferably 64% or more, and further preferably 64.5% or more. ２ The content is 72% or less, preferably 71.5% or less, more preferably 71% or less, and even more preferably 70.5% or less.

[0030] Al ２ O ３ is an effective component for increasing the surface compressive stress due to chemical strengthening. It is also a component of β-spodumene. ２ O ３ The content of Al is 12.0% or more, preferably 12.5% ​​or more, more preferably 13.0% or more, and further preferably 13.5% or more. On the other hand, in order to prevent the devitrification temperature of the glass from becoming too high, ２ O ３ The content is 19.0% or less, preferably 18.8% or less, more preferably 18.5% or less, and further preferably 18.2% or less.

[0031] In addition, from the viewpoint of the ease of the phase transition to β-spodumene, SiO ２ Content and Al ２ O ３ Content ratio SiO ２ / Al ２ O ３ is preferably 3.5 or more, more preferably 3.53 or more, and even more preferably 3.57 or more. ２ / Al ２ O ３ is preferably 5.6 or less, more preferably 5.4 or less, even more preferably 5.2 or less, and particularly preferably 5.0 or less.

[0032] Li ２ O is a component that forms surface compressive stress through ion exchange and is a constituent of β-spodumene. ２ The content of O is 9% or more, preferably 9.2% or more, more preferably 9.4% or more, and further preferably 9.6% or more. ２ Since O is also a component that promotes the formation of devitrification, Li ２ The O content is 13% or less, preferably 12.8% or less, more preferably 12.6% or less, and further preferably 12.4% or less.

[0033] K ２ O is a component that improves the meltability of glass. ２ The content of O is 0.1% or more, preferably 0.2% or more, more preferably 0.25% or more, and further preferably 0.3% or more. ２ The O content is 2% or less, preferably 1.8% or less, more preferably 1.5% or less, and even more preferably 1.2% or less, from the viewpoint of facilitating precipitation of β-spodumene crystals.

[0034] TiO ２ is a component that forms crystal nuclei for crystallized glass and also prevents fragments from scattering when the chemically strengthened glass is broken, and may be contained. ２When TiO is contained, the content is preferably 0.05% or more, more preferably 0.1% or more, and further preferably 0.15% or more. ２ If the content of Fe is too high, the glass is likely to be devitrified when melted, and the quality of the chemically strengthened glass may be reduced. ２ O ３ When TiO is contained as an impurity, a complex called an ilmenite complex is formed, which tends to cause yellow or brown coloring. ２ The content is 1% or less, preferably 0.5% or less, more preferably 0.25% or less, and may be 0%.

[0035] Li ２ O content and Al ２ O ３ Content ratio Li ２ O / Al ２ O ３ It is considered that Li influences the crystal growth rate during the heat treatment for crystallization, and if the crystallization proceeds rapidly, the grain size of the crystal increases, and the transparency of the crystallized glass decreases. ２ O / Al ２ O ３ is 0.88 or less, preferably 0.86 or less, and more preferably 0.84 or less. ２ O / Al ２ O ３ is 0.50 or more, preferably 0.55 or more, more preferably 0.60 or more, and even more preferably 0.65 or more.

[0036] Li ２ O content and Al ２ O ３ Content and SiO ２ The ratio of each component to the sum of the contents is L = Li ２ O / (Li ２ O+Al ２ O ３ +SiO ２ ) × 100, A = Al ２ O ３ / (Li ２ O+Al ２ O３ +SiO ２ )×100, S=SiO ２ / (Li ２ O+Al ２ O ３ +SiO ２ ) × 100, X = 100 - (L + S / 2), Y = S × √3 / 2. In this case, from the viewpoint of obtaining highly transparent crystallized glass, the range of X = 48 to 56 and Y = 55 to 70 is preferred, the range of X = 50 to 55 and Y = 56 to 66 is more preferred, the range of X = 51 to 54 and Y = 57 to 65 is even more preferred, and the range of X = 51.2 to 53.8 and Y = 58 to 64.8 is most preferred.

[0037] The glass composition is not particularly limited, but specific examples include glass compositions in the following ranges: (1) X = 48.0 to 56.0 and Y = 68.0 to 70.0 (2) X = 51.0 to 53.5 and Y = 64.5 to 68.0 (3) X = 51.2 to 52.6 and Y = 63.3 to 64.8 (4) X = 52.0 to 53.0 and Y = 61.6 to 63.6 (5) X = 52.0 to 53.0 and Y = 64.0 to 65.5 (6) X = 52.3 to 53.3 and Y = 59.8 to 61.8 (7) X = 53.2 to 54.2 and Y = 58.0 to 60.8 (8) X = 48.0 to 56.0 and Y = 55.0 to 58.0

[0038] Na ２ O is the above K ２ Like O, Na is a component that improves the meltability of glass and is preferably contained. ２ The O content is preferably 0.5% or more, more preferably 1% or more. ２ If the amount of O is too much, β-spodumene crystals become difficult to precipitate or the chemical strengthening properties deteriorate, so the amount is preferably 2% or less, more preferably 1.8% or less, and even more preferably 1.6% or less.

[0039] Also Na ２ O content and K content ２ Sum of O content Na ２ O+K ２In order to increase transparency, O is preferably 4.5% or less, more preferably 3.5% or less, further preferably 3.0% or less, and particularly preferably 2.5% or less. ２ O+K ２ The O content is preferably 0.85% or more.

[0040] Also Na ２ O content and Li ２ O content ratio Na ２ O / Li ２ From the viewpoint of increasing the deep layer stress, O is preferably 0.2 or less, more preferably 0.15 or less. ２ O / Li ２ O is preferably 0.03 or more, more preferably 0.06 or more.

[0041] SnO ２ is a component that forms crystal nuclei during crystallization treatment and has a high effect of promoting the precipitation of β-spodumene crystals, so it may be contained. ２ The content of SnO is preferably 0.3% or more, more preferably 0.5% or more, and further preferably 0.8% or more. ２ The content of SnO is preferably 6% or less, more preferably 5% or less, and further preferably 4% or less. ２ is also a component that enhances solarization resistance. ２ The content is preferably 0.05% or more, more preferably 0.1% or more.

[0042] ZrO ２ is a component that increases the mechanical strength of the mother glass and is also a component that forms crystal nuclei during crystallization treatment, so it is preferable to include ZrO. ２ The content of ZrO is preferably 0.5% or more, and more preferably 1% or more. ２ The content is preferably 8% or less, more preferably 6% or less, and even more preferably 4% or less.

[0043] Nb ２ O５ is a component that forms crystal nuclei during crystallization treatment, and SnO ２ and ZrO ２ , TiO ２ The content is preferably 0.05% or more, more preferably 0.1% or more, and is preferably 5% or less, more preferably 4% or less, and may be 0%.

[0044] As mentioned above, the components constituting the crystal nuclei include TiO ２ , SnO ２ , ZrO ２ , Nb ２ O ５ In order to enhance the transparency of the glass, it is more preferable to adjust not only the content of each but also the balance of each crystal nucleus component. ２ , SnO ２ , TiO ２ and Nb ２ O ５ The sum of the contents of (ZrO ２ + SnO ２ + TiO ２ +Nb ２ O ５ From the viewpoint of transparency, ZrO is preferably 0.1% or more, more preferably 0.5% or more, and even more preferably 1% or more. ２ + SnO ２ + TiO ２ +Nb ２ O ５ is preferably 4% or less, more preferably 3.5% or less, and even more preferably 3% or less. ２ , SnO ２ , TiO ２ and Nb ２ O ５ The sum of the contents of (ZrO ２ + SnO ２ + TiO ２ +Nb ２ O ５ ) ZrO ２ ZrO content ratio ２ / (ZrO ２ + SnO ２ + TiO２ +Nb ２ O ５ ) is preferably 0.4 or more, more preferably 0.45 or more, from the viewpoint of transparency. ２ / (ZrO ２ + SnO ２ + TiO ２ +Nb ２ O ５ ) is preferably 1.0 or less, more preferably 0.95 or less.

[0045] P ２ O ５ is not essential, but has the effect of promoting phase separation of glass and accelerating crystallization, and may be contained. ２ O ５ When P is contained, the content is preferably 0.1% or more, more preferably 0.5% or more, even more preferably 1% or more, and particularly preferably 2% or more. ２ O ５ If the content of P is too high, the chemically strengthened glass is likely to scatter fragments when broken, and the acid resistance is significantly reduced. ２ O ５ The content of is preferably 6% or less, more preferably 5% or less, even more preferably 4% or less, particularly preferably 3% or less, and extremely preferably 2% or less. In order to further increase the acid resistance, it is preferable that it is not substantially contained.

[0046] B ２ O ３ is a component that improves the chipping resistance and meltability of the glass for chemical strengthening or the chemically strengthened glass, and may be contained. ２ O ３ is not required, but B ２ O ３ When B is contained, the content is preferably 0.5% or more, more preferably 1% or more, and even more preferably 2% or more in order to improve the melting property. ２ O ３ If the content exceeds 5%, striae will occur during melting and the quality of the glass for chemical strengthening will tend to deteriorate, so it is preferably 5% or less. ２ O ３The content of is more preferably 4% or less, further preferably 3% or less, and particularly preferably 1% or less. In order to improve acid resistance, it is preferable that it is substantially not contained.

[0047] MgO is a component that increases the surface compressive stress of chemically strengthened glass and also suppresses the scattering of fragments when the chemically strengthened glass is broken, and may be contained. When MgO is contained, the content is preferably 0.1% or more, more preferably 0.3% or more. On the other hand, if too much MgO is added, the viscosity of the glass decreases and devitrification and phase separation during melting are likely to occur. Therefore, 5% or less is preferable, 4% or less is more preferable, and 3% or less is even more preferable.

[0048] CaO is a component that improves the meltability of chemically strengthened glass and may be contained to prevent devitrification during melting and improve solubility while suppressing an increase in the thermal expansion coefficient. When CaO is contained, the content is preferably 0.1% or more, more preferably 0.3% or more. On the other hand, in order to improve the ion exchange properties, the CaO content is preferably 4% or less, more preferably 3% or less, and particularly preferably 2% or less.

[0049] From the viewpoint of improving the meltability of the glass, the sum of the MgO content and the CaO content (MgO + CaO) is preferably 0.1% or more, more preferably 0.5% or more. From the viewpoint of reducing the haze value, the sum of the MgO content and the CaO content (MgO + CaO) is preferably 6% or less, more preferably 5% or less, and even more preferably 4% or less.

[0050] SrO is a component that improves the meltability of chemically strengthened glass and also improves the refractive index of the glass. SrO may be contained to improve the transmittance of the crystallized glass and reduce the haze value by bringing the refractive index of the glass phase remaining after crystallization closer to that of the precipitated crystals. When SrO is contained, the content is preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.5% or more, and particularly preferably 1% or more. On the other hand, if the SrO content is too high, the ion exchange rate decreases, so it is preferably 2.5% or less, more preferably 1.8% or less, even more preferably 1.5% or less, particularly preferably 1% or less, and most preferably 0.5% or less.

[0051] BaO is a component that improves the meltability of chemically strengthened glass and also improves the refractive index of the glass. BaO may be added to improve the transmittance of the crystallized glass and reduce the haze value by bringing the refractive index of the glass phase remaining after crystallization closer to that of the β-spodumene crystal phase. When BaO is added, the content is preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.5% or more, and particularly preferably 1% or more. On the other hand, if the BaO content is too high, the ion exchange rate decreases, so the content is preferably 2% or less, more preferably 1.5% or less, even more preferably 1% or less, particularly preferably 0.5% or less, and most preferably 0.3% or less.

[0052] ZnO is a component that reduces the thermal expansion coefficient of chemically strengthened glass and increases its chemical durability, and may be included to improve the transmittance of the crystallized glass and reduce the haze value. When ZnO is included to bring the refractive index of the glass phase remaining after crystallization closer to that of the β-spodumene crystal phase, the content is preferably 0.5% or more, more preferably 1% or more, even more preferably 1.5% or more, and particularly preferably 2% or more. On the other hand, in order to suppress devitrification during melting, the content is preferably 4% or less, more preferably 3% or less, and even more preferably 2% or less.

[0053] From the viewpoint of adjusting the haze to an appropriate value, the sum of the contents of SrO, BaO, and ZnO (SrO + BaO + ZnO) is preferably 2% or less, more preferably 1% or less, and even more preferably 0.8% or less. The sum of the contents of SrO, BaO, and ZnO may be 0%, and even when at least one of them is contained, it is preferably 0.05% or more, more preferably 0.1% or more.

[0054] Y ２ O ３ , La ２ O ３ , and Ta ２ O ５ are components that make it difficult for chemically strengthened glass to scatter fragments when broken, and may be contained to increase the refractive index. ２ O ３ The content of La is preferably 0.1% or more, more preferably 0.3% or more, and is preferably 3% or less, more preferably 1.5% or less, and may be 0%. ２ O ３ The content of Ta is preferably 0.1% or more, more preferably 0.3% or more, and is preferably 3% or less, more preferably 1.5% or less, and may be 0%. ２ O ５ The content is preferably 0.1% or more, more preferably 0.3% or more, and is preferably 3% or less, more preferably 1.5% or less, and may be 0%.

[0055] Also Y ２ O ３ , La ２ O ３ The total content of Y ２ O ３ +La ２ O ３ is preferably 0.5% or more, more preferably 1% or more, further preferably 1.5% or more, particularly preferably 2% or more. ２ O ３ +La ２ O ３The content of Y is preferably 4% or less, more preferably 3% or less, even more preferably 2% or less, particularly preferably 1% or less, and may even be 0%. ２ O ３ , La ２ O ３ and Ta ２ O ５ The total content Y ２ O ３ +La ２ O ３ +Ta ２ O ５ is preferably 0.5% or more, more preferably 1% or more, further preferably 1.5% or more, and particularly preferably 2% or more. ２ O ３ +La ２ O ３ +Ta ２ O ５ is preferably 4% or less, more preferably 3% or less, even more preferably 2% or less, particularly preferably 1% or less, and may even be 0%.

[0056] In addition, the present glass contains CeO ２ It may contain CeO ２ has the effect of oxidizing glass, and SnO ２ When a large amount of SnO is contained, ２ may inhibit the reduction of CeO to SnO, a coloring component, thereby suppressing coloration. ２ When CeO is contained, the content is preferably 0.03% or more, more preferably 0.05% or more, and even more preferably 0.07% or more. ２ When used as an oxidizing agent, CeO ２ The content is preferably 1.5% or less, more preferably 1% or less, in order to increase transparency.

[0057] Furthermore, when the tempered glass is used after being colored, a coloring component may be added within a range that does not hinder the achievement of the desired chemical strengthening characteristics. ３ O ４ , MnO ２ , Fe ２ O ３, NiO, CuO, Cr ２ O ３ , V ２ O ５ , Bi ２ O ３ , SeO ２ , Er ２ O ３ , Nd ２ O ３ The total content of the coloring components is preferably 1% or less, and may be 0%. If a higher visible light transmittance of the glass is desired, it is preferable that these components are not substantially contained.

[0058] The present glass may contain, as impurities due to raw materials, machinery, equipment, etc., at least one metal element selected from Hf, Ni, Mn, Fe, Ga, Pt, Rh, Mo, Au, Sm, and Pr, and at least one oxide, chloride, nitride, and sulfide of any of the above metal elements. The impurity content is preferably 1% by mass or less, more preferably 0.5% by mass or less, and most preferably 0.1% by mass or less.

[0059] This glass contains SO as a fining agent during glass melting. ３ , chloride, tin oxide, sulfide, fluoride, etc. may be appropriately contained. ２ O ３ and Sb ２ O ３ It is preferable that As is not substantially contained. ２ O ３ and Sb ２ O ３ When As is contained, the content of each is preferably 0.3% or less, more preferably 0.1% or less, and most preferably substantially none is contained. ２ O ３ and Sb ２ O ３ "Substantially free of" means that the content of each is less than 0.1%.

[0060] The crystallization peak temperature Tp of the present glass is preferably 800 to 950°C, more preferably 820 to 930°C. The crystallization peak temperature Tp is the temperature at which heat generation due to crystallization reaches its peak. A Tp in the above range is preferable because it facilitates control during the crystallization heat treatment. The crystallization peak temperature Tp can be measured by differential scanning calorimetry (DSC).

[0061] The viscosity log η of the present glass at the crystallization peak temperature Tp is preferably in the range of 6.5 to 9.0, more preferably 6.7 to 8.8, even more preferably 6.9 to 8.6, and particularly preferably 8.0 to 8.6. When the viscosity log η at the crystallization peak temperature Tp is in the above range, the crystal growth rate during heat treatment is suppressed, making it easier to control the particle size. The viscosity log η at Tp is determined by measuring the viscosity of the glass at a temperature of 10 ２ The temperature T2 at which the viscosity becomes 10 dPa s (also called the temperature at which the viscosity log η is 2) and the temperature T3 at which the viscosity becomes 10 ４ The temperature T4 at which the viscosity becomes dPa·s (also referred to as the temperature when the viscosity logη is 4) is measured, and the measured values ​​are used to calculate the coefficients of the VFT formula.

[0062] From the viewpoint of transparency, the present glass preferably has a difference Tp-Tg between the glass transition temperature Tg and the crystallization peak temperature Tp of 150 to 300°C, more preferably 170 to 250°C.

[0063] The devitrification temperature of the present glass is preferably 1500° C. or lower, more preferably 1450° C. or lower, from the viewpoint of the fire-resistant temperature of each member in the production equipment. A devitrification temperature within the above range is preferable because it facilitates mass production of the glass.

[0064] The devitrification viscosity of the present glass is preferably log η of 3 to 5, more preferably 3.5 to 4.5, from the viewpoint of ease of molding in mass production.

[0065] The temperature at which the viscosity log η of the present glass is 2 (viscosity T2) is preferably 1450 to 1800°C, and more preferably 1500 to 1770°C. The viscosity T2 is an index of the melting temperature of the glass, and a viscosity T2 in the above range is preferable because it enables mass production. The viscosity T2 can be measured using a rotational viscometer.

[0066] The temperature at which the viscosity log η of the present glass is 4 (viscosity T4) is preferably 1000 to 1400°C, more preferably 1150 to 1350°C. Viscosity T4 is an index of the glass forming temperature, and a range in which viscosity T4 is within this range is preferred because it facilitates forming of plate glass. Viscosity T4 can be measured using a rotational viscometer.

[0067] <Glass Manufacturing Method> The present glass can be manufactured, for example, by the following method. Glass raw materials are blended to obtain glass of a desired composition, and heated and melted in a glass melting furnace. The molten glass is then homogenized by bubbling, stirring, adding a fining agent, etc., and formed into a glass plate of a predetermined thickness by a known forming method, and slowly cooled. Alternatively, the molten glass may be formed into a block, slowly cooled, and then cut into a plate.

[0068] Examples of forming methods for plate glass include the float method, the press method, the fusion method, and the down-draw method. The present glass has a viscosity suitable for any of the forming methods, and can be mass-produced. In particular, when producing large glass plates, the float method is preferred. In addition, continuous forming methods other than the float method, such as the fusion method and the down-draw method, are also preferred.

[0069] Plate-shaped amorphous glass can be produced, for example, by the following method: Glass raw materials are mixed to obtain glass of a desired composition, and heated and melted in a glass melting furnace. The molten glass is then homogenized by bubbling, stirring, adding a fining agent, etc., and formed into a glass plate of a predetermined thickness by a known forming method, followed by annealing.

[0070] The forming method is preferably a float method. The float method refers to a method in which molten glass is poured onto a molten metal bath and formed into a sheet. In this specification, the upstream side of the molten metal bath refers to the side into which the molten glass flows, and the downstream side refers to the side from which the glass formed into a ribbon shape is discharged.

[0071] FIG. 1 shows a schematic diagram of a glass manufacturing apparatus using the float process. As shown in FIG. 1, the glass manufacturing apparatus using the float process includes a melting furnace 10, a float bath 20, and an annealing furnace (lehr) 30. In manufacturing glass using the float process, glass raw materials are first melted in the melting furnace 10 to obtain molten glass. The melting furnace 10 includes a melting furnace 11, in which glass raw materials 1 charged therein are melted to obtain molten glass 2. More specifically, the melting furnace 11 includes a melting tank 12 on the upstream side and a cooling tank 13 on the downstream side, which are connected by a neck 14 (or throat). The glass raw materials 1 are melted on the upstream side (i.e., the melting tank) to obtain molten glass 2, and the temperature of the molten glass 2 is adjusted on the downstream side.

[0072] Next, molten glass 2 is continuously supplied from the upstream side onto the surface of the molten metal bath 21 stored in the float bath 20 to form a glass ribbon 3. The formed glass ribbon 3 is then drawn out from the downstream end of the float bath 20 and introduced into an annealing furnace (lehr) 30 where it is annealed to produce sheet glass. The glass ribbon 3 introduced into the lehr 30 is annealed while being transported to the annealing furnace (not shown) by a transport means such as a roller conveyor. Because the molten glass 2 on the molten metal bath 21 and the glass ribbon 3 in the lehr 30 are continuous, the transport speed (lehr speed) within the lehr 30 depends on the speed at which the molten glass 2 flows from upstream to downstream on the molten metal bath 21. Because the glass ribbon 3 in the lehr 30 is solidified but the molten glass 2 flows, the speed of the molten glass 2 is slower than the lehr speed, and the speed of the molten glass 2 on the molten metal bath 21 tends to be faster downstream. The type of molten metal is not particularly limited, but examples include molten tin.

[0073] (Rear speed during float forming) The rare speed is preferably 20 m / h or more, more preferably 100 m / h or more, even more preferably 200 m / h or more, particularly preferably 300 m / h or more, and most preferably 400 m / h or more. If the rare speed is too high, the quality of the glass tends to deteriorate, so the rare speed is preferably 1200 m / h or less, more preferably 1000 m / h or less, even more preferably 900 m / h or less, particularly preferably 850 m / h or less, and most preferably 800 m / h or less.

[0074] (Hydrogen Concentration in the Atmosphere During Float Forming) The hydrogen concentration in the atmosphere during float forming can be adjusted by the concentration of a gas such as a reducing gas or an oxidizing gas supplied to the glass during float forming, the amount of gas sprayed, the main surface to be sprayed, the treatment temperature and time, etc. Examples of the gas supply include supply from a hole in the ceiling that is arranged at an interval from the molten metal bath 21, and spraying the gas onto the glass sheet in an annealing furnace.

[0075] Examples of reducing gases include nitrogen gas, hydrogen gas, carbon monoxide gas, and a mixture thereof. The reducing gas may contain an inert gas such as air, nitrogen, or argon as a carrier gas. The reducing gas can be supplied, for example, from a hole in the ceiling spaced apart from the molten metal bath 21. Specific examples of reducing gas treatment conditions include a mixed gas flow rate of 0.1 to 100 cc / min and a treatment temperature of 600 to 1200°C. The mixed gas is, for example, a mixed gas of nitrogen gas and hydrogen gas, containing 80 to 99.5% by volume of nitrogen gas and 0.5 to 20% by volume of hydrogen gas.

[0076] The oxidizing gas may be, for example, sulfur dioxide (SO ２Examples of suitable oxidizing gases include fluorine-containing gas, hydrofluoric acid gas, oxygen gas, or a mixture thereof. The oxidizing gas may contain an inert gas such as air, nitrogen, or argon as a carrier gas. The oxidizing gas may further contain water vapor. The oxidizing gas is sprayed onto the main surfaces (preferably at least the top surface, specifically, for example, only the first main surface, only the second main surface, or both the first and second main surfaces) of the glass sheet in an annealing furnace. Specific examples of oxidizing gas treatment conditions include a mixed gas flow rate of 0.1 to 100 cc / min and a treatment temperature of 600 to 1200°C. The mixed gas may have an oxygen content ranging from 0.5% by volume to 10% by volume or higher. In some embodiments, the mixed gas may be oxygen gas with a maximum concentration of 100% by volume.

[0077] (Temperature of Molten Metal Bath During Float Forming) The temperature of the molten metal bath is preferably 700° C. or higher, more preferably 800° C. or higher, even more preferably 850° C. or higher, and particularly preferably 900° C. or higher. From the viewpoint of volatilization of metallic tin, the temperature is preferably 1300° C. or lower, more preferably 1250° C. or lower, even more preferably 1200° C. or lower, and particularly preferably 1150° C. or lower.

[0078] In order to suppress surface crystallization during float forming and to obtain a crystallized glass plate exhibiting excellent surface flatness, the glass plate has a crystal growth rate of 6000 μm / hour or less, preferably 5000 μm / hour or less, more preferably 4500 μm / hour or less, even more preferably 4000 μm / hour or less, and particularly preferably 3500 μm / hour or less at any temperature between 950° C. and 1260° C. When used as amorphous glass, a lower crystal growth rate is preferable.

[0079] The glass plate has a first main surface having a radius of curvature of 10 μm from the surface to a depth of 10 μm, from the viewpoint of obtaining a crystallized glass plate in which the viscosity of the glass surface is kept high, surface crystallization during crystallization treatment is suppressed, and excellent surface flatness is exhibited. ２ The average total content of O is ２ It is preferable that the content of R is 0.5 to 4.0% by mass less than the total content of O. ２ O is Li２ O, Na ２ O and K ２ The sum of O.

[0080] R from the surface to a depth of 10 μm on the first principal surface ２ Average total content of O and R at the center of thickness ２ The difference from the total content of O is preferably 0.6 mass% or more, more preferably 0.7 mass% or more, even more preferably 0.8 mass% or more, and particularly preferably 0.9 mass% or more. The difference is preferably 3.5 mass% or less, more preferably 3.2 mass% or less, even more preferably 3.0 mass% or less, and particularly preferably 2.8 mass% or less. ２ The average total O content can be measured by a wet method.

[0081] FIG. 2 shows a graph of the relationship between the depth from the first main surface and R in one embodiment of the glass plate. ２ 2 shows the relationship between the thickness and the O concentration. In FIG. 2, t represents the thickness, and t / 2 represents the thickness center. As shown in FIG. 2, in one embodiment, in the region from the first main surface to a depth x1, the R at the thickness center decreases as the depth from the first main surface increases. ２ Gradually increase the R ２ O concentration increases.

[0082] R of glass plate ２ The O concentration distribution is determined in the production of a glass sheet by, for example, the floating rate, the hydrogen concentration in the air, the temperature of the molten metal bath and the dealkalization treatment, and the glass composition (e.g., SnO ２ The mass percentage of oxides is expressed as the R content in the base composition. ２ The total content of O is preferably 5.0 to 15% by mass.

[0083] From the viewpoint of improving the light extraction efficiency, the glass according to this embodiment preferably satisfies the following formulas (1) and (2) in terms of mass percentage based on oxides: 0.10≦(ΔSnO ２ )T≦1.0 (1) 0.30≦(ΔSnO ２ )B≦1.5 (2) (ΔSnO ２ ) T: [SnO at the center of the plate thickness２ concentration (%)] to [SnO ２ Concentration (%)] minus the value (%) (ΔSnO ２ ) B: [SnO on the second principal surface ２ concentration (%)] to [SnO at the center of the plate thickness ２ Concentration (%)] minus the value (%) where SnO ２ The concentration is measured by XRF. From the viewpoint of further increasing the light extraction efficiency, (ΔSnO ２ )T is preferably 0.20 mass% or more, more preferably 0.30 mass% or more, even more preferably 0.40 mass% or more, particularly preferably 0.45 mass% or more, and most preferably 0.50 mass% or more. ２ ) T is preferably 0.9% by mass or less, more preferably 0.8% by mass or less, even more preferably 0.7% by mass or less, particularly preferably 0.6% by mass or less, and most preferably 0.5% by mass or less.

[0084] In the glass according to this embodiment, from the viewpoint of suppressing surface crystallization of the glass, the β-OH value at the first main surface is preferably 0.02 to 0.10 / mm smaller, more preferably 0.02 to 0.09 / mm smaller, more preferably 0.02 to 0.08 / mm smaller, and even more preferably 0.03 to 0.07 / mm smaller than the β-OH value at the center of the plate thickness, where the β-OH value is measured by FT-IR-ATR (attenuated total reflection Fourier transform infrared spectroscopy) method.

[0085] <Glass-ceramics> The glass-ceramics according to the embodiment of the present invention (hereinafter also referred to as the present glass-ceramics) is glass obtained by heat-treating the present glass to crystallize it. Therefore, the mother glass of the present glass-ceramics has the same glass composition as the present glass. That is, the mother glass of the present glass-ceramics has, in terms of mole percentage based on oxides, the following composition: SiO ２ 63 to 72%, Al ２ O ３ 12.0-19.0%, Li ２ O 9-13%, K ２ 0.1-2% O, TiO ２ Contains 0 to 1% of Li２ O content and Al ２ O ３ Content ratio Li ２ O / Al ２ O ３ is 0.50 to 0.88.

[0086] The composition of the mother glass of the present glass-ceramics is the same as that of the present glass described above, including the preferred embodiments.

[0087] The present crystallized glass preferably contains β-spodumene as a crystalline phase. This makes it easier to obtain crystallized glass with excellent chemical strengthening properties. The content of β-spodumene in the present crystallized glass is preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, and particularly preferably 60% by mass or more. Also, it is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less. The present crystallized glass may also contain β-quartz solid solution (vergilite) as a crystalline phase. These crystals may form solid solutions and dissolve various elements. Particularly, elements that dissolve include alkali metals (Na, K) and alkaline earth metals (Mg, Ca, Sr, Ba), but are not limited to these. Furthermore, ZrO ２ and its solid solutions, SnO ２ The β-quartz solid solution in the present crystallized glass may contain trace amounts of crystals of the β-quartz solid solution. The content of the β-quartz solid solution in the present crystallized glass is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. The content is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less.

[0088] The crystallization rate of the present crystallized glass is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and particularly preferably 20% by mass or more in order to improve mechanical strength.In order to improve transparency, it is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less.A small crystallization rate is also excellent in that it is easy to be heated and bent and molded.Crystallization rate is determined by crushing a part of the crystallized glass, identifying the precipitated crystals by powder X-ray diffraction, and then using the Rietveld method.

[0089] The average particle size of the precipitated crystals of the present crystallized glass is preferably 5 nm or more, particularly preferably 10 nm or more, from the viewpoint of at least one of reducing the haze value and increasing the mechanical strength. In order to improve transparency, it is preferably 200 nm or less, more preferably 180 nm or less, even more preferably 150 nm or less, particularly preferably 120 nm or less, and most preferably 100 nm or less. The average particle size of the precipitated crystals can be determined from a transmission electron microscope (TEM) image or an FE-SEM image.

[0090] The Young's modulus of this crystallized glass is preferably 84GPa or more, more preferably 84.5GPa or more, and even more preferably 85GPa or more, in order to improve mechanical properties such as fracture toughness.In addition, in order to facilitate polishing, the Young's modulus is preferably 100GPa or less, more preferably 98GPa or less, and even more preferably 96GPa or less.Young's modulus can be measured by ultrasonic pulse method (JIS R1602:1995).

[0091] The fracture toughness value K of this glass-ceramic ＩＣ is preferably 0.8 MPa m １／２ More preferably, 1 MPa m １／２ The fracture toughness value K is preferably in this range because the chemically strengthened glass is less likely to scatter into fragments when broken. ＩＣ is measured by the DCDC method [Reference: M. Y. He, M. R. Turner and A. G. Evans, Acta Metall. Mater. 43 (1995) 3453.]. Specifically, using a sample having the shape shown in FIG. 3 and a SHIMADZU Autograph AGS-X5KN, the stress intensity factor K1 (unit: MPa m) as shown in FIG. １／２ The K1-v curve, which shows the relationship between the stress intensity factor K1 at 0.1 m / s and the crack propagation velocity v (unit: m / s), was measured, and the obtained Region III data was regressed and extrapolated using a linear equation to determine the fracture toughness value K1. ＩＣ Let's say.

[0092] The fracture toughness value Kc of the present glass-ceramics is preferably 0.8 MPa m １／２More preferably, 1.0 MPa m １／２ or more, and more preferably 1.2 MPa m １／２ This range is preferable because the chemically strengthened glass is less likely to shatter when broken. The fracture toughness value Kc refers to the fracture toughness value measured by the indentation method (IF method) specified in JIS R1607:2010.

[0093] The present crystallized glass contains crystals, so it has a high Vickers hardness. Therefore, it is scratch-resistant and has excellent abrasion resistance. In order to increase the abrasion resistance, the Vickers hardness is preferably 680 or more, more preferably 700 or more, and even more preferably 740 or more. If the hardness is too high, it becomes difficult to process, so the Vickers hardness of the present crystallized glass is preferably 1100 or less, more preferably 1050 or less, and even more preferably 1000 or less.

[0094] The visible light transmittance of this crystallized glass is preferably 70% or more when the thickness is 0.7 mm. With such a visible light transmittance, when used as a cover glass for a portable display, the display screen is easy to see. A visible light transmittance of 80% or more is more preferable, and 85% or more is even more preferable. The higher the visible light transmittance, the more preferable it is, but it is usually 91% or less. 90% is the same transmittance as that of non-crystallized amorphous glass. "Visible light transmittance" refers to the average transmittance of light with wavelengths of 380 nm to 780 nm.

[0095] The chromaticity L of the present glass-ceramics in the visible light region ＊ The value is preferably 70 or more, more preferably 75 or more, 80 or more, 85 or more, 90 or more, 91 or more, and most preferably 92 or more. If this value is too low, transparency cannot be obtained. Chromaticity L in the visible light region ＊ The value is determined by calculation in accordance with JIS Z 8781-1.

[0096] Chromaticity a of the present glass-ceramics in the visible light region ＊The value is preferably within ±5, more preferably within ±4, ±3, ±2.5, ±2, ±1.5, ±1, ±0.8, ±0.6, and most preferably within ±0.5. If this value is large in the negative direction, it tends to appear green, and if it is large in the positive direction, it tends to appear red. Chromaticity a in the visible light range ＊ The value is determined by calculation in accordance with JIS Z 8781-1.

[0097] The glass-ceramic in the visible light region ＊ The value is preferably within ±20, more preferably within ±15, ±10, ±8, ±6.5, ±6, ±5.5, ±5, ±4.5, and most preferably within ±4. If this value is large in the negative direction, the color tends to appear blue, and if it is large in the positive direction, the color tends to appear yellow. Chromaticity b in the visible light range ＊ The value is determined by calculation in accordance with JIS Z 8781-1.

[0098] The haze value of this crystallized glass, converted into a thickness of 0.7 mm, is preferably 15% or less from the viewpoint of transparency, and is preferably 12% or less, 10% or less, 8% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, and most preferably 0.5% or less. The smaller the haze value, the more preferable. The haze value is measured using a C light source in accordance with JIS K7136:2000.

[0099] The Poisson's ratio of this crystallized glass is preferably 0.22 or more, more preferably 0.24 or more, and even more preferably 0.25 or more in order to improve the melting property of glass and improve mechanical properties.In addition, the Poisson's ratio is preferably 0.30 or less, more preferably 0.29 or less in order to improve devitrification property.Poisson's ratio can be calculated from the longitudinal wave sound velocity and shear wave sound velocity measured by ultrasonic pulse method (JIS R1602:1995).

[0100] The thickness (t) of the crystallized glass is preferably 3 mm or less, more preferably 2 mm or less, 1.6 mm or less, 1.1 mm or less, 0.9 mm or less, 0.8 mm or less, and 0.7 mm or less, in order to obtain a sufficient strength by chemical strengthening. The thickness (t) is preferably 0.3 mm or more, more preferably 0.4 mm or more, and even more preferably 0.5 mm or more.

[0101] <Method for Producing Crystallized Glass> The present crystallized glass can be obtained by heat-treating the present glass.

[0102] The heat treatment may be 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 maintained for a certain period of time at a second treatment temperature higher than the first treatment temperature, or a one-stage heat treatment in which the temperature is maintained at a specific treatment temperature and then cooled to room temperature.

[0103] In the case of two-stage heat treatment, the first treatment temperature is preferably in a temperature range where the crystal nucleation rate is high in the glass composition, and the second treatment temperature is preferably in a temperature range where the crystal growth rate is high in the glass composition. Also, it is preferable to maintain the first treatment temperature for a long time so that a sufficient number of crystal nuclei are generated. By generating a large number of crystal nuclei, the size of each crystal becomes small, and highly transparent crystallized glass is obtained.

[0104] In the case of a two-stage treatment, for example, a first treatment temperature of 450°C to 800°C is held for 1 hour to 6 hours, and then a second treatment temperature of, for example, 600°C to 1000°C, more preferably 700 to 980°C, and even more preferably 800 to 950°C is held for 15 minutes to 6 hours. In the case of a one-stage treatment, for example, a temperature of 500°C to 1000°C, more preferably 550 to 900°C, and even more preferably 650 to 850°C is held for 1 hour to 6 hours. The heat treatment may be performed stepwise by holding at two or more levels of temperature, or may be performed while applying a temperature gradient.

[0105] The molten glass may be homogenized and formed into a glass plate of a predetermined thickness, or may be formed into a block, followed by continuous crystallization.

[0106] When heat-treating plate-shaped glass, examples of the setter plate include silicon carbide plates, silicon nitride plates, SiN plates, alumina plates, mullite cordierite plates, mullite plates, and crystallized glass plates. Furthermore, materials with high thermal conductivity are preferred to reduce temperature unevenness during heat treatment. The thermal conductivity of the setter plate is preferably 2 W / (m K) or more, more preferably 20 W / (m K) or more, and even more preferably 40 W / (m K) or more.

[0107] A release agent can be used to prevent the glass from adhering to the setter plate. Examples of release agents include alumina cloth and glass cloth. Other examples include particulate boron nitride, alumina, minerals, etc. Particulate release agents may be mixed with a solvent and applied by spraying, etc. When particulate release agents are used, the average particle size is preferably 80 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less.

[0108] When heat-treating glass, it may be laminated to improve work efficiency. When laminating, it is preferable to use a release agent between the glass sheets. Also, a setter plate may be placed between the glass sheets.

[0109] The crystallized glass obtained by the above procedure is ground and polished as necessary to form a crystallized glass plate. When the crystallized glass plate is cut to a predetermined shape and size or chamfered, it is preferable to perform the cutting or chamfering before performing the chemical strengthening treatment. This allows a compressive stress layer to be formed on the end surface by the subsequent chemical strengthening treatment.

[0110] <Chemically strengthened glass> Chemically strengthened glass according to an embodiment of the present invention (hereinafter also referred to as the present chemically strengthened glass) is glass obtained by chemically strengthening the present glass (amorphous glass) or the present glass-ceramics described above.

[0111] Chemical strengthening is a process in which glass is brought into contact with a metal salt by, for example, immersing the glass in a molten salt (e.g., a sodium salt or a potassium salt) containing metal ions with a large ionic radius (typically Na ions or K ions), thereby replacing metal ions with a small ionic radius (typically Na ions or Li ions) in the glass with metal ions with a large ionic radius (typically Na ions or K ions for Li ions, and K ions for Na ions).

[0112] Examples of molten salts used in chemical strengthening include nitrates, sulfates, carbonates, and chlorides. Nitrates include lithium nitrate, sodium nitrate, potassium nitrate, cesium nitrate, and silver nitrate. Sulfates include lithium sulfate, sodium sulfate, potassium sulfate, cesium sulfate, and silver sulfate. Carbonates include lithium carbonate, sodium carbonate, and potassium carbonate. Chlorides include lithium chloride, sodium chloride, potassium chloride, cesium chloride, and silver chloride. These molten salts may be used alone or in combination.

[0113] The treatment conditions for the chemical strengthening treatment include time and temperature, taking into consideration the glass composition, the type of molten salt, and chemical strengthening characteristics such as the surface compressive stress and the depth of the compressive stress layer desired for the final chemically strengthened glass. Can be selected.

[0114] In the present invention, the chemical strengthening treatment may be performed only once, or multiple times (multi-stage strengthening) under two or more different conditions may be performed. Here, for example, as the first-stage chemical strengthening treatment, the chemical strengthening treatment is performed under conditions in which the DOL is large and the CS is relatively small. Then, as the second-stage chemical strengthening treatment, the chemical strengthening treatment is performed under conditions in which the DOL is small and the CS is relatively high. The internal tensile stress (CT) can be reduced while increasing the CS of the outermost surface of the chemically strengthened glass.

[0115] When chemical strengthening is performed in one step, for example, the glass or the glass-ceramics is immersed in a molten salt at a temperature of preferably 350 to 450° C. for about 1 to 6 hours. The above temperature conditions allow compressive stress due to chemical strengthening to be imparted to a sufficient depth, and the above treatment time allows compressive stress due to chemical strengthening to be imparted to a sufficient depth, which is preferable.

[0116] When chemical strengthening is performed in two stages, for example, the glass or the glass-ceramics is immersed for about 0.1 to 10 hours in a molten salt (e.g., sodium nitrate) at a temperature of about 350 to 500° C. This causes ion exchange between Li ions in the glass and Na ions in the metal salt, forming a relatively deep compressive stress layer.

[0117] Next, the specimen is immersed in a metal salt (e.g., potassium nitrate) at a temperature of about 350 to 500°C for about 0.1 to 10 hours. This generates a large compressive stress in the compressive stress layer formed in the previous treatment, for example, within a depth of about 10 μm. This two-stage treatment tends to produce a stress profile with a large surface compressive stress value.

[0118] This chemically strengthened glass has a compressive stress value of the surface layer when chemically strengthened using a metal salt of Na ions (Na-CS ０ ) is preferably 150 MPa or more, more preferably 200 MPa or more, the higher the better. The chemically strengthened glass has a compressive stress depth (Na-DOL) of preferably 60 μm or more, more preferably 70 μm or more, the deeper the better. The chemically strengthened glass has a compressive stress value (K-CS) of the surface layer when chemically strengthened using a metal salt of K ions. ０ The compressive stress depth (K-DOL) of the chemically strengthened glass when chemically strengthened using a metal salt of K ions is preferably 3 μm or more, more preferably 4 μm or more, and the deeper the better.

[0119] In this chemically strengthened glass, when the glass plate after Na ion exchange is subjected to X-ray diffraction measurement, the diffraction peak position preferably shifts to a lower angle compared to before chemical strengthening. The shift to the lower angle side is thought to be due to the increase in lattice spacing caused by ion exchange between small ions in the crystal and large ions in the molten salt. Note that when the glass after ion exchange is powdered or the surface is polished, if the compressive stress value or compressive stress depth on the surface is small, a shift to the lower angle side may not be observed.

[0120] <Cover Glass and Electronic Devices> The present glass, the present crystallized glass, and the present chemically strengthened glass are particularly useful as cover glass for mobile electronic devices such as mobile phones, smartphones, personal digital assistants (PDAs), and tablet devices. They are 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. They are also useful as building materials such as window glass, tabletops, interiors of automobiles and airplanes, and cover glass for these materials.

[0121] As described above, this specification discloses the following glasses and glass-ceramics: [1] In mole percent based on oxides, SiO ２ 63 to 72%, Al ２ O ３ 12.0-19.0%, Li ２ O 9-13%, K ２ 0.1-2% O, TiO ２ Contains 0 to 1% of Li ２ O content and Al ２ O ３ Content ratio Li ２ O / Al ２ O ３ [2] The glass according to [1], which is a float glass. [3] The glass according to [1] or [2], which has a viscosity log η at a crystallization peak temperature Tp of 6.5 to 9. [4] The glass according to any one of [1] to [3], which has a sum of the MgO content and the CaO content of 0.1 to 6%. [5] The glass according to any one of [1] to [3], which has, in mole percent on an oxide basis, Na ２ O 0.5 to 2%, SnO２ 0 to 6%, ZrO ２ 0.5 to 8%, P ２ O ５ 0 to 6%, Nb ２ O ５ Contains 0 to 5% of Na ２ O content and Li ２ O content ratio Na ２ O / Li ２ O is 0.2 or less, and As ２ O ３ and Sb ２ O ３ [6] The glass according to any one of [1] to [4], which is substantially free of SiO ２ Content and Al ２ O ３ Content ratio SiO ２ / Al ２ O ３ [7] The glass according to any one of [1] to [5], wherein Na is 3.5 to 5.6. ２ O content and K content ２ [8] The glass according to any one of [1] to [6], wherein the sum of the contents of ZrO is 0.85 to 4.5%. ２ , SnO ２ , TiO ２ and Nb ２ O ５ The sum of the contents of (ZrO ２ + SnO ２ + TiO ２ +Nb ２ O ５ [9] The glass according to any one of [1] to [7], wherein ZrO ２ , SnO ２ , TiO ２ and Nb ２ O ５ The sum of the contents of (ZrO ２ + SnO ２ + TiO ２ +Nb ２ O ５ ) ZrO ２ ZrO content ratio ２ / (ZrO ２ + SnO ２ + TiO ２ +Nb２ O ５ The glass according to any one of [1] to [8], wherein the sum of the contents of SrO, BaO, and ZnO (SrO + BaO + ZnO) is 0 to 2%.

[11] The glass according to any one of [1] to

[10] , wherein the impurity is at least one selected from a metal element, an oxide having the metal element, a chloride having the metal element, a nitride having the metal element, and a sulfide having the metal element, and the metal element is at least one selected from Hf, Ni, Mn, Fe, Ga, Pt, Rh, Mo, Au, Sm, and Pr.

[12] A chemically strengthened glass obtained by chemically strengthening the glass according to any one of [1] to

[11] using a metal salt of Na ions, wherein the chemically strengthened glass has a compressive stress depth (Na-DOL) of 60 μm or more.

[13] A chemically strengthened glass obtained by chemically strengthening the glass according to any one of [1] to

[11] using a metal salt of K ions, wherein the chemically strengthened glass has a compressive stress depth (K-DOL) of 3 μm or more.

[14] The base glass contains, in mole percent on an oxide basis, SiO ２ 63 to 72%, Al ２ O ３ 12.0-19.0%, Li ２ O 9-13%, K ２ 0.1-2% O, TiO ２ Contains 0 to 1% of Li ２ O content and Al ２ O ３ Content ratio Li ２ O / Al ２ O ３ is 0.50 to 0.88.

[15] Glass-ceramics according to

[14] , containing β-spodumene as a crystalline phase.

[16] Glass-ceramics according to

[14] or

[15] , containing 10 mass% or more of β-spodumene as a crystalline phase.

[17] Glass-ceramics according to any one of

[14] to

[16] , containing β-quartz solid solution as a crystalline phase.

[18] Glass-ceramics according to any one of

[14] to

[17] , containing 30 mass% or more of β-quartz solid solution as a crystalline phase.

[19] Fracture toughness value KＩＣ is 0.8 MPa m １／２

[14] Glass-ceramics according to any one of

[14] to

[18] , having a haze value of 15% or less when converted to a thickness of 0.7 mm.

[20] Glass-ceramics according to any one of

[14] to

[19] , having a haze value of 15% or less when converted to a thickness of 0.7 mm.

[21] Glass-ceramics according to any one of

[14] to

[20] , having a Young's modulus of 84 GPa or more.

[22] Chemically strengthened glass obtained by chemically strengthening the glass-ceramics according to any one of

[14] to

[21] using a metal salt of Na ions, wherein the chemically strengthened glass has a compressive stress depth (Na-DOL) of 60 μm or more.

[23] Chemically strengthened glass obtained by chemically strengthening the glass-ceramics according to any one of

[14] to

[21] using a metal salt of K ions, wherein the chemically strengthened glass has a compressive stress depth (K-DOL) of 3 μm or more.

[0122] The present invention will be described in more detail below using examples, but the present invention is not limited to these. Examples 1-1 to 1-12 are comparative examples, and Examples 1-13 to 1-44 are working examples. Examples 2-1 to 2-15 are comparative examples, and Examples 2-16 to 2-57 are working examples. Examples 3-1 to 3-4 are comparative examples, and Examples 3-5 to 3-11 are working examples.

[0123] <Examples 1-1 to 1-44: Glass Production> Glass raw materials were blended to yield the compositions shown in Tables 1 to 6 in terms of oxide-based mole percentages, and weighed out to yield 400 g of glass. The mixed raw materials were then placed in a platinum crucible and placed in an electric furnace at 1500 to 1700°C, where they were melted for approximately 3 hours, degassed, and homogenized. The resulting molten glass was poured into a metal mold and held at a temperature approximately 50°C higher than the glass transition point for 1 hour, after which it was cooled to room temperature at a rate of 0.5°C / min to obtain a glass block. The resulting glass block was cut and ground, and finally both sides were mirror-polished to obtain a glass plate with a thickness of 0.7 mm.

[0124] <Examples 2-1 to 2-57: Production of Crystallized Glass> The glass plates produced with any of the compositions of Examples 1-1 to 1-44 were subjected to two-stage heat treatment under the conditions shown in Tables 7 to 16 to obtain crystallized glass plates.

[0125] <Examples 3-1 to 3-11: Production of Chemically Tempered Glass> Each glass plate of the glass-ceramics of any of Examples 2-1 to 2-57 was chemically strengthened under the following conditions (1) or (2) to obtain a glass plate of chemically strengthened glass. The glass-ceramics used are shown in Tables 17 and 18. (1) Chemical strengthening was performed using 100% sodium nitrate salt at 380°C for 4 hours. (2) Chemical strengthening was performed using 100% potassium nitrate salt at 380°C for 4 hours.

[0126] <Evaluation of Glass> Each of the glass plates obtained above was evaluated as follows.

[0127] (Devitrification temperature) Crushed glass particles were placed in a platinum dish and subjected to heat treatment for 17 hours in an electric furnace controlled at a constant temperature. The heat-treated glass was observed under a polarizing microscope, and the devitrification temperature was estimated using an evaluation method for the presence or absence of devitrification. For example, in the table, "1450-1500" means that devitrification occurred when heat treated at 1450°C, but not when treated at 1500°C. In this case, the devitrification temperature is 1450°C or higher but less than 1500°C. Furthermore, "-1400" means that it is less than 1400°C. "1400-" means that it is higher than 1400°C. A devitrification temperature of less than 1500°C was considered to be acceptable.

[0128] (Viscosity T2, Viscosity T4) Viscosity measured by a rotational viscometer (based on ASTM C 965-96) was 10 ２ Temperatures T2 and T10 at which viscosity becomes dPa s ４ The temperature T4 at which the viscosity reached dPa s was measured. T2 and T4 are sometimes expressed as log η = 2 and log η = 4, respectively. Evaluation criteria: If the viscosity log η = 2 was 1600 to 1770°C, it was judged to be good. If the viscosity log η = 4 was 1200 to 1350°C, it was judged to be good.

[0129] (Glass Transition Temperature Tg) Based on JIS R1618:2002, a thermal expansion curve was obtained using a thermal dilatometer (TD5000SA manufactured by Bruker AXS) at a temperature rise rate of 10°C / min, and the glass transition point Tg (unit: °C) was determined from the obtained thermal expansion curve.

[0130] (Crystallization Peak Temperature Tp) The crystallization peak temperature was calculated from the temperature with the highest peak intensity among the DSC exothermic peaks measured by the following test method. Approximately 70 mg of glass was crushed using an alumina mortar and pestle and classified into 53 to 106 μm particles. Approximately 50 mg of the crushed glass powder was placed in a platinum pan and measured using a differential scanning calorimeter (DSC) from room temperature to 1100°C at a heating rate of 10°C / min.

[0131] (Viscosity log η at Tp) The viscosity at Tp was calculated using the coefficients of the VFT formula calculated using the values ​​of log η = 2 and log η = 4 measured with a rotational viscometer. A viscosity log η at Tp of 6.5 or more was judged to be good.

[0132] (Young's Modulus of Crystallized Glass) Young's modulus (E) (unit: GPa) was measured by the ultrasonic pulse method (JIS R1602:1995). A Young's modulus of 84 GPa or more was judged to be good.

[0133] (Poisson's ratio of crystallized glass) Poisson's ratio was calculated from the longitudinal wave sound velocity and the shear wave sound velocity measured by the ultrasonic pulse method (JIS R1602:1995). A Poisson's ratio of 0.22 or more was judged to be good.

[0134] (Haze Value) The haze value was measured using a C light source in accordance with JIS K3761: 2000. A haze value of 15% or less converted into a thickness of 0.7 mm was judged to be good.

[0135] (Fracture toughness K ＩＣ ) Fracture toughness value K by DCDC method ＩＣ (unit: MPa m １／２ ) was measured by the DCDC method with reference to the method described in M. Y. He, M. R. Turner and A. G. Evans, Acta Metall. Mater. 43 (1995) 3453. Using a sample having the shape shown in FIG. 3 and a SHIMADZU Autograph AGS-X5KN, the stress intensity factor K1 (unit: MPa m) as shown in FIG. １／２The K1-v curve, which shows the relationship between the stress intensity factor K1 at 0.1 m / s and the crack propagation velocity v (unit: m / s), was measured, and the obtained Region III data was regressed and extrapolated using a linear equation to determine the fracture toughness value K1. ＩＣ It was decided.

[0136] (Powder X-ray Diffraction) For each of the glass plates of the crystallized glasses of Examples 2-1 to 2-57, powder X-ray diffraction was measured under the following conditions to identify the crystal species and crystal content of the precipitated crystals. Measuring device: Rigaku Corporation Smart Lab X-ray used: CuKα ray Measurement range: 2θ = 10° to 80° Speed: 1° / min Step: 0.01° When the crystal species was identified, as shown in Tables 7 to 16, virgilite (i.e., β-quartz solid solution), β-spodumene (SP), or a combination thereof (virgilite + SP) was confirmed.

[0137] (Stress measurement of chemically strengthened glass) (1) Compressive stress value of the surface layer when chemically strengthened using 100% sodium nitrate salt (Na-CS ０ ) and compressive stress depth (Na-DOL) were measured using a scattered light photoelastic stress meter SLP-2000 manufactured by Orihara Seisakusho Co., Ltd. ０ If the Na-DOL is 150 MPa or more, it is judged to be good. If the Na-DOL is 60 μm or more, it is judged to be good. (2) The compressive stress value of the surface layer when chemically strengthened using 100% potassium nitrate salt (K-CS ０ The compressive stress depth (K-DOL) and compressive stress depth (K-CS) were measured using a scattered light photoelastic stress meter SLP-2000 manufactured by Orihara Seisakusho Co., Ltd. ０ If K-DOL is 3 μm or more, it is considered to be good.

[0138] The compositions and properties of the glasses are shown in Tables 1 to 6.

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145] The crystallization conditions and properties of the crystallized glasses are shown in Tables 7 to 16.

[0146]

[0147]

[0148]

[0149]

[0150]

[0151]

[0152]

[0153]

[0154]

[0155]

[0156] The tempering conditions and properties of chemically tempered glass are shown in Tables 17 to 18. In Tables 17 to 18, "nd" means that no tempering was performed or that the tempering was below the measurement limit.

[0157]

[0158]

[0159] From the above results, TiO ２ In the glass of Example 1-1 in which the content of SiO exceeds 1%, the crystal species when made into glass-ceramics is vergielite as shown in Example 2-1 of Table 7, and therefore, even when chemical strengthening was performed as shown in Example 3-1 of Table 17, the Na-CS was low and chemical strengthening properties were not obtained. ２In the glasses of Examples 1-2 and 1-10 in which the content of Al exceeds 72%, the crystal species when made into crystallized glass is vergielite, as shown in Example 2-2 in Table 7 and Example 2-11 in Table 8, and therefore it is expected that chemical strengthening properties will not be obtained, as in Example 1-1. ２ O ３ In the glass of Example 1-3 in which the content of LiO was less than 12.0%, as shown in Example 2-3 of Table 7, when it was made into glass-ceramics, surface crystallization occurred, and crystallization properties could not be obtained. ２ / Al ２ O ３ In the glass of Example 1-4, where K exceeds 0.88, when it was made into glass-ceramics, surface crystallization occurred as shown in Example 2-4 in Table 7, and crystallization properties could not be obtained. ２ The glass of Example 1-5, which had an O content of 0%, was made into glass-ceramics, and then chemically strengthened with 100% potassium nitrate, as shown in Example 3-2 of Table 17, but no stress was generated, and therefore chemical strengthening properties were not obtained. ２ The same is expected to be true for the glasses of Examples 1-7 to 1-9 and 1-10 to 1-12, which have an O content of 0%. ２ / Al ２ O ３ The glasses of Examples 1-6 to 1-7, which had a value of more than 0.88, had high haze when made into crystallized glass, as shown in Examples 2-6 to 2-9 in Tables 7 to 8. In particular, the glass of Example 1-6 was whitened as crystallized glass, and therefore transparency was not obtained.

[0160] The glasses of Examples 1-13 to 1-44 were shown to contain β-spodumene (SP) as a crystal seed when made into crystallized glass, as shown in Examples 2-16 to 2-57, and to satisfy the crystallinity. Furthermore, the glasses of Examples 1-13 to 1-44 were shown to have low haze and satisfy the transparency when made into crystallized glass, as shown in Examples 2-16 to 2-57 ... ２ Since it contains O and contains β-spodumene (SP) as a crystal seed when made into crystallized glass, it has been shown that it satisfies or will satisfy chemical strengthening properties, as shown in Examples 3-5 to 3-10.

[0161] 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 July 17, 2024 (Patent Application No. 2024-114047), July 17, 2024 (Patent Application No. 2024-114101), September 20, 2024 (Patent Application No. 2024-163789), and December 4, 2024 (Patent Application No. 2024-211809), the contents of which are incorporated herein by reference.

[0162] REFERENCE SIGNS LIST 1 glass raw material 2 molten glass 3 glass ribbon 10 melting furnace 11 melting furnace 12 melting tank 13 cooling tank 14 neck 20 float bath 21 molten metal bath 30 annealing furnace (lehr)

Claims

1. In mole percent based on oxide, SiO ２ 63 to 72%, Al ２ O ３ 12.0-19.0%, Li ２ O 9-13%, K ２ 0.1-2% O, TiO ２ Contains 0 to 1% of Li ２ O content and Al ２ O ３ Content ratio Li ２ O / Al ２ O ３ A glass having a viscosity of 0.50 to 0.

88.

2. The glass of claim 1, which is float glass.

3. The glass according to claim 1, wherein the viscosity log η at the crystallization peak temperature Tp is 6.5 to 9.

4. The glass according to claim 1, wherein the sum of the MgO content and the CaO content is 0.1 to 6%.

5. In mole percent based on oxide, Na ２ O 0.5 to 2%, SnO ２ 0 to 6%, ZrO ２ 0.5 to 8%, P ２ O ５ 0 to 6%, Nb ２ O ５ Contains 0 to 5% of Na ２ O content and Li ２ O content ratio Na ２ O / Li ２ O is 0.2 or less, and As ２ O ３ and Sb ２ O ３ 10. The glass of claim 1, wherein the glass is substantially free of:

6. SiO ２ Content and Al ２ O ３ Content ratio SiO ２ / Al ２ O ３ 2. The glass of claim 1, wherein the .lambda.

7. Na ２ O content and K content ２ 2. The glass according to claim 1, wherein the sum of the O contents is 0.85 to 4.5%.

8. ZrO ２ , SnO ２ , TiO ２ and Nb ２ O ５ The sum of the contents of (ZrO ２ + SnO ２ + TiO ２ +Nb ２ O ５ 2. The glass of claim 1, wherein Zn is 0.1 to 4%.

9. ZrO ２ , SnO ２ , TiO ２ and Nb ２ O ５ The sum of the contents of (ZrO ２ + SnO ２ + TiO ２ +Nb ２ O ５ ) ZrO ２ ZrO content ratio ２ / (ZrO ２ + SnO ２ + TiO ２ +Nb ２ O ５ 2. The glass of claim 1, wherein σ is 0.4 to 1.

0.

10. The glass according to claim 1, wherein the sum of the contents of SrO, BaO and ZnO (SrO + BaO + ZnO) is 0 to 2%.

11. The glass according to claim 1, containing as an impurity at least one selected from a metal element, an oxide having said metal element, a chloride having said metal element, a nitride having said metal element, and a sulfide having said metal element, wherein said metal element is at least one selected from Hf, Ni, Mn, Fe, Ga, Pt, Rh, Mo, Au, Sm, and Pr.

12. Chemically strengthened glass obtained by chemically strengthening the glass according to any one of claims 1 to 11 using a metal salt of Na ions, wherein the compressive stress depth (Na-DOL) is 60 μm or greater.

13. Chemically strengthened glass obtained by chemically strengthening the glass according to any one of claims 1 to 11 using a metal salt of K ions, wherein the compressive stress depth (K-DOL) is 3 μm or greater.

14. The mother glass is SiO, expressed as mole percent on an oxide basis. ２ 63 to 72%, Al ２ O ３ 12.0-19.0%, Li ２ O 9-13%, K ２ 0.1-2% O, TiO ２ Contains 0 to 1% of Li ２ O content and Al ２ O ３ Content ratio Li ２ O / Al ２ O ３ is 0.50 to 0.

88.

15. The crystallized glass according to claim 14, which contains β-spodumene as a crystalline phase.

16. The crystallized glass according to claim 14, which contains 10% by mass or more of β-spodumene as a crystalline phase.

17. The crystallized glass according to claim 14, which contains a β-quartz solid solution as a crystalline phase.

18. The crystallized glass according to claim 14, which contains 30 mass % or more of β-quartz solid solution as a crystalline phase.

19. Fracture toughness value K ＩＣ is 0.8 MPa m １／２ The crystallized glass according to claim 14, wherein 20. The crystallized glass according to claim 14, having a haze value of 15% or less when converted into a thickness of 0.7 mm.

21. The crystallized glass according to claim 14, having a Young's modulus of 84 GPa or more.

22. Chemically strengthened glass obtained by chemically strengthening the glass-ceramics according to any one of claims 14 to 21 using a metal salt of Na ions, wherein the compressive stress depth (Na-DOL) is 60 μm or more.

23. Chemically strengthened glass obtained by chemically strengthening the glass-ceramics according to any one of claims 14 to 21 using a metal salt of K ions, wherein the compressive stress depth (K-DOL) is 3 μm or more.

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