Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C10/00—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
  • C03C10/0018—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition containing SiO2, Al2O3 and monovalent metal oxide as main constituents
  • C03C10/0027—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition containing SiO2, Al2O3 and monovalent metal oxide as main constituents containing SiO2, Al2O3, Li2O as main constituents
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B32/00—Thermal after-treatment of glass products not provided for in groups C03B19/00, C03B25/00 - C03B31/00 or C03B37/00, e.g. crystallisation, eliminating gas inclusions or other impurities; Hot-pressing vitrified, non-porous, shaped glass products
  • C03B32/02—Thermal crystallisation, e.g. for crystallising glass bodies into glass-ceramic articles
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B27/00—Tempering or quenching glass products
  • C03B27/012—Tempering or quenching glass products by heat treatment, e.g. for crystallisation; Heat treatment of glass products before tempering by cooling
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C10/00—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C10/00—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
  • C03C10/0054—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition containing PbO, SnO2, B2O3
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C21/00—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C21/00—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface
  • C03C21/001—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface in liquid phase, e.g. molten salts, solutions
  • C03C21/002—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface in liquid phase, e.g. molten salts, solutions to perform ion-exchange between alkali ions
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/097—Glass compositions containing silica with 40% to 90% silica, by weight containing phosphorus, niobium or tantalum

Definitions

• the present invention relates to crystallized glass and its manufacturing method, chemically strengthened glass, and electronic devices.
• Chemically strengthened glass is widely used for the cover glass of mobile devices, as it must be strong enough not to break easily even if the mobile device is dropped.
• Chemically strengthened glass is produced by immersing the glass in a molten salt such as sodium nitrate to cause ion exchange between alkali ions contained in the glass and alkali ions having a larger ionic radius contained in the molten salt. This is glass in which a compressive stress layer is formed on the surface layer of the glass.
• Crystallized glass is made by depositing crystals in glass, and is harder and more scratch-resistant than amorphous glass that does not contain crystals. And, the crystallized glass that can be chemically strengthened can have high strength while preventing breakage compared to amorphous glass.
• Patent Document 1 describes that crystallized glass containing predetermined crystals can be chemically strengthened by ion exchange.
• an object of the present invention is to provide a crystallized glass that can obtain excellent strength through chemical strengthening and has excellent radio wave transmission.
• Another object of the present invention is to provide a chemically strengthened glass that is excellent in both strength and radio wave transmission.
• each of the dielectric constant and the dielectric loss tangent In order to improve radio wave transparency, it is preferable to make each of the dielectric constant and the dielectric loss tangent relatively small.
• the radio wave transmittance of the crystallized glass can be affected by the radio wave transmittance of the contained crystals.
• the inventors of the present invention have found that lithium disilicate-based crystals are particularly excellent in radio wave transmission in that they have a small dielectric constant.
• the dielectric loss tangent of the lithium disilicate-based crystal can change depending on the crystal state.
• the value of the dielectric loss tangent of the lithium disilicate-based crystal can be reduced by reducing the proportion of Li ions occupying the Li ion sites of the lithium disilicate-based crystal.
• the inventors of the present invention have found that radio wave transmission can be further improved by this, and have completed the present invention.
• the present invention relates to 1 to 11 below.
• the crystals contained in the largest amount on a mass basis are lithium disilicate-based crystals, Crystallized glass, wherein the ratio of Li ions to Li ion sites in the lithium disilicate-based crystal is less than 95%.
• the crystallized glass according to 1 above which has a light transmittance of 85% or more in a wavelength range of 400 nm to 1000 nm in terms of a thickness of 0.7 mm.
• 3. The crystallized glass according to 1 or 2 above, wherein the haze value in terms of thickness of 0.7 mm is less than 5% in the wavelength range of 400 nm to 1000 nm. 4.
• the crystallized glass according to 1 or 2 above wherein the sum of the value obtained by multiplying the dielectric loss tangent tan ⁇ at 10 GHz and 20° C. by 100 and the dielectric constant Dk at 10 GHz and 20° C. is 7.5 or less. 3.
• the crystallized glass according to 1 or 2 above which has a dielectric constant Dk of 5.8 or less at 5.10 GHz and 20°C. 6.
• mole percentage display based on oxides SiO 2 55-85%, Al 2 O 3 1-5%, B2O3 0-5.0 %, P2O5 0.5-5.0 %, TiO 2 0-5.0%, ZrO 2 0-5.0%, Li 2 O 15-25%, Na 2 O 0-5.0%, 3.
• the crystallized glass according to 1 or 2 above containing 0 to 5.0% in total of 0 to 5.0% of K 2 O and one or more selected from MgO, CaO, SrO and BaO. 7. In mole percentage display based on oxides, Na 2 O 0.1-5.0% 7. Crystallized glass according to 6 above.
• the method for producing crystallized glass according to 1 or 2 above subjecting the amorphous glass to at least one step of heat treatment;
• the temperature of the heat treatment is all 750 ° C. or less, In each of the heat treatments, the rate of temperature increase to the treatment temperature and the rate of temperature decrease from the treatment temperature are both 0.5 ° C./min or more.
• a method for producing crystallized glass is
• a chemically strengthened glass having a compressive stress layer on the surface The surface compressive stress value is 50 MPa or more, Chemically strengthened glass, which is the crystallized glass according to 1 or 2 above. 10. 9. The chemically strengthened glass according to 9 above, which is plate-shaped and has different proportions of alkali metal elements between the surface layer and the center in the thickness direction.
• An electronic device comprising the crystallized glass described in 1 above.
• the crystallized glass of the present invention can be chemically strengthened. Further, in the crystallized glass of the present invention, the ratio of Li ions occupying the Li ion sites of the lithium disilicate-based crystal is small. Thereby, the crystallized glass of the present invention can obtain excellent strength by chemical strengthening, and also has excellent radio wave transmission.
• the chemically strengthened glass of the present invention is crystallized glass, and is excellent in both strength and radio wave transmission because the ratio of Li ions occupying the Li ion sites of the lithium disilicate-based crystal is small.
• chemically strengthened glass refers to glass that has been subjected to chemical strengthening treatment
• chemically strengthened glass refers to glass that has not been subjected to chemical strengthening treatment
• the "base composition of chemically strengthened glass” is the glass composition of chemically strengthened glass.
• the glass composition at a depth of half the plate thickness t is the base composition of the chemically strengthened glass, except for the case where extreme ion exchange treatment is performed.
• the glass composition is expressed in terms of mol percentage based on oxides, and mol% is simply expressed as "%".
• substantially does not contain means that it is below the level of impurities contained in raw materials, etc., that is, it is not intentionally contained. Specifically, it is less than 0.1 mol %, for example.
• the stress profile refers to the compressive stress value expressed with the depth from the glass surface as a variable.
• the “compressive stress layer depth (DOL)” is the depth at which the compressive stress value (CS) is zero.
• Internal tensile stress value (CT)” refers to the tensile stress value at a depth of half the plate thickness t of the glass.
• the stress profile in this specification can be measured using a scattered light photoelastic stress meter (eg SLP-1000 manufactured by Orihara Seisakusho Co., Ltd.). Scattered light photoelastic stress meters are affected by surface scattering, and the accuracy of measurement near the surface of a sample may decrease.
• the compressive stress value expressed as a function of depth follows the complementary error function, so the internal stress value By measuring , the surface stress value can be obtained. If the complementary error function is not followed, the surface portion is measured by another method, such as a method of measuring with a surface stress meter.
• amorphous glass and “crystallized glass” are sometimes collectively referred to as “glass”.
• amorphous glass refers to glass in which no diffraction peak indicating crystals is observed by powder X-ray diffraction.
• crystals refers to heat treatment of "amorphous glass” to precipitate crystals, and crystals are precipitated in the glass.
• crystals are precipitated in the glass.
• crystals refers to glass in which diffraction peaks indicating crystals are observed by X-ray diffraction (XRD).
• X-ray diffraction measurement can be performed, for example, by a method of measuring the range of 2 ⁇ from 10° to 80° using CuK ⁇ rays.
• identification of crystals precipitated in crystallized glass can be performed by powder X-ray diffraction (PXRD) measurement.
• PXRD powder X-ray diffraction
• Rietveld analysis enables quantitative analysis of crystalline phases and amorphous phases and structural analysis of crystalline phases.
• the Rietveld method is described in "Crystal Analysis Handbook” Edited by the Crystallographic Society of Japan, “Crystal Analysis Handbook” (Kyoritsu Shuppan, 1999, pp. 492-499). That is, in the present specification, the content, crystallinity, etc. of each crystal in the crystallized glass can be obtained, for example, by Rietveld analysis of an XRD pattern obtained by powder X-ray diffraction (PXRD) measurement.
• Light transmittance refers to parallel light transmittance at a wavelength of 400 nm to 1000 nm.
• haze value means a value measured according to JIS K3761:2000 using a C light source.
• crystal In the crystallized glass according to the present embodiment (hereinafter also referred to as the present crystallized glass), crystals contained in the largest amount on a mass basis are lithium disilicate-based crystals. In the lithium disilicate-based crystal, the ratio of Li ions to Li ion sites is less than 95%.
• This crystallized glass contains lithium disilicate-based crystals.
• lithium disilicate-based crystals include lithium disilicate (Li 2 Si 2 O 5 ), Li 2-x Na x Si 2 O 5 , Li 2 Si 2-3x Al 4x O 5 and the like. be done.
• the radio wave transmittance of the crystallized glass is improved.
• the content of the lithium disilicate-based crystals in the present crystallized glass is preferably 20% by mass or more, more preferably 25% by mass or more, even more preferably 30% by mass or more, from the viewpoint of improving radio wave transparency, and 35% by mass. % or more is particularly preferred, 40 mass % or more is even more preferred, 45 mass % or more is even more preferred, 50 mass % or more is even more preferred, and 55 mass % or more is most preferred.
• the content is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, particularly preferably 75% by mass or less, and 70% by mass.
• the following are more preferable, and 65% by mass or less is most preferable.
• the content of lithium disilicate-based crystals is preferably 20 to 90% by mass, more preferably 25 to 85% by mass, even more preferably 30 to 80% by mass, even more preferably 35 to 75% by mass, and 40 to 70% by mass.
• % by weight is particularly preferred, 45 to 65% by weight is more preferred, 50 to 65% by weight is even more preferred, and 55 to 65% by weight is most preferred.
• crystals contained in the largest amount on a mass basis are lithium disilicate-based crystals.
• the ratio of Li ions to Li ion sites is less than 95%.
• the Li ion sites where Li ions do not exist are considered to contain at least one of vacancies and elements other than Li (heterogeneous elements).
• the different element is not particularly limited, but includes, for example, an element having a valence close to that of Li, specifically Na, Al, and the like.
• the proportion of Li ions occupying the Li ion sites is obtained by the Rietveld analysis described above.
• the unit "%" of the ratio of Li ions to Li ion sites means "atom %".
• the ratio of Li ions occupying the Li ion sites is less than 95% from the viewpoint of improving radio wave transparency, preferably less than 90%, more preferably less than 85%, even more preferably less than 80%, particularly less than 75%.
• less than 70% is more particularly preferred, less than 65% is even more preferred, and less than 60% is most preferred.
• the proportion of Li ions occupying Li ion sites is preferably 30% or more, more preferably 35% or more, even more preferably 40% or more, particularly preferably 45% or more, and 50% or more. is more preferred.
• the proportion of Li ions occupying Li ion sites is preferably 30% or more and less than 90%, more preferably 35% or more and less than 85%, still more preferably 40% or more and less than 80%, and even more preferably 45% or more and less than 75%.
• 50% or more and less than 70% is particularly preferable, 50% or more and less than 65% is even more preferable, and 50% or more and less than 60% is even more preferable.
• the crystals contained in the largest amount on a mass basis are lithium disilicate-based crystals, and in the lithium disilicate-based crystals, the proportion of Li ions occupying the Li ion sites is less than 95%. , excellent radio wave permeability. The reason for this is considered as follows.
• each of the dielectric constant and the dielectric loss tangent is relatively small.
• the radio wave transmittance of the crystallized glass can be affected by the radio wave transmittance of the contained crystals.
• lithium disilicate-based crystals are particularly excellent in radio wave transmission in that they have a small relative dielectric constant.
• the dielectric loss tangent of the lithium disilicate-based crystal can change depending on the crystal state. Specifically, it was found that the value of the dielectric loss tangent of the lithium disilicate-based crystal can be reduced by reducing the proportion of Li ions occupying the Li ion sites of the lithium disilicate-based crystal.
• the reason for this is that in the crystal structure of lithium disilicate-based crystals, the Li ion site has the largest atomic fluctuation when an electric field is applied, which is considered to be a factor that increases the dielectric loss tangent. That is, by substituting vacancies or an element (heterogeneous element) other than Li (heterogeneous element) into the Li ion sites to contain them, it is possible to suppress the swinging amount of Li ions in the crystal as a whole. It is presumed that this reduces the dielectric loss tangent of the lithium disilicate-based crystal and the crystallized glass containing the crystal.
• the crystals contained in the largest amount on a mass basis are lithium disilicate-based crystals, so the dielectric constant tends to be small.
• the dielectric loss tangent tends to be small due to the small proportion of Li ions occupying the Li ion sites.
• the crystallized glass of the present invention has excellent radio wave transmittance as compared with conventional ones.
• the present crystallized glass may optionally contain crystals other than lithium disilicate-based crystals (hereinafter also referred to as other crystals).
• Other crystals may be of one type or plural types. Examples of other crystals include, but are not limited to, petalite (LiAlSi 4 O 10 )-based crystals, SiO 2 -based crystals, lithium metasilicate (Li 2 SiO 3 )-based crystals, and eucryptite (LiAlSiO 4 )-based crystals. and the like.
• petalite (LiAlSi 4 O 10 )-based crystals are preferable from the viewpoint of improving the transparency of the crystallized glass.
• the present crystallized glass may not contain other crystals.
• the preferred content thereof is, for example, preferably 50% by mass or less, preferably 45% by mass, from the viewpoint of improving radio wave transmission, for each type of crystal.
• the following is more preferable, 40% by mass or less is even more preferable, 35% by mass or less is particularly preferable, 30% by mass or less is even more preferable, and 25% by mass or less is most preferable.
• the content of other crystals is preferably 0% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and 15% by mass or more for each type of crystal. is particularly preferred.
• the content of other crystals is preferably 0 to 50% by mass, more preferably 5 to 45% by mass, still more preferably 10 to 40% by mass, and even more preferably 15 to 35% by mass for each type of crystal. , 15 to 30% by weight is particularly preferred, and 15 to 25% by weight is even more particularly preferred.
• the total content of other crystals is preferably 50% by mass or less, more preferably 45% by mass or less, even more preferably 40% by mass or less, and particularly 35% by mass or less, from the viewpoint of improving radio wave transparency.
• 30% by mass or less is more preferable, and 25% by mass or less is most preferable.
• the total content of other crystals is preferably 0% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and particularly preferably 15% by mass or more.
• the total content of other crystals is preferably 0 to 50% by mass, more preferably 5 to 45% by mass, even more preferably 10 to 40% by mass, even more preferably 15 to 35% by mass, and 15 to 30% by mass. % is particularly preferred, and 15-25% by weight is even more particularly preferred.
• the difference obtained by subtracting the content ratio (mass%) of the second largest crystal contained in this crystallized glass from the content ratio (mass%) of the lithium disilicate-based crystal is the radio wave transmission. From the viewpoint of improving the properties, it is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, particularly preferably 25% by mass or more, even more preferably 30% by mass or more, and 35% by mass or more. is more preferable, and 40% by mass or more is most preferable. On the other hand, the difference is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less from the viewpoint of improving transparency.
• Such a difference is preferably 10 to 60% by mass, more preferably 15 to 55% by mass, even more preferably 20 to 50% by mass, even more preferably 25 to 50% by mass, particularly preferably 30 to 50% by mass, and 35% by mass. ⁇ 50% by weight is more particularly preferred, and 40-50% by weight is even more preferred.
• the "content ratio (% by mass) of the second most contained crystal on the basis of mass" shall be 0% by mass.
• the degree of crystallinity of the present crystallized glass is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, and even more preferably 65% by mass, from the viewpoint of improving radio wave permeability and increasing strength. Above is particularly preferable, more preferably 70% by mass or more, even more preferably 75% by mass or more, and most preferably 80% by mass or more. From the viewpoint of improving transparency, the crystallinity is preferably 95% by mass or less, more preferably 90% by mass or less.
• Crystallinity is preferably 50 to 95% by mass, more preferably 55 to 95% by mass, still more preferably 60 to 95% by mass, even more preferably 65 to 95% by mass, particularly preferably 70 to 95% by mass, 75 to 95% by weight is more particularly preferred, and 80 to 90% by weight is even more preferred.
• the proportion of the amorphous phase is preferably 50% by mass or less, more preferably 45% by mass or less, even more preferably 40% by mass or less, and even more preferably 35% by mass or less from the viewpoint of improving radio wave transmission properties. Particularly preferred is 30% by mass or less, even more preferably 25% by mass or less, and most preferably 20% by mass or less. From the viewpoint of improving transparency, the proportion of the amorphous phase is preferably 5% by mass or more, more preferably 10% by mass or more. The proportion of the amorphous phase is preferably 5 to 50% by mass, more preferably 5 to 45% by mass, even more preferably 5 to 40% by mass, even more preferably 5 to 35% by mass, and 5 to 30% by mass.
• the amorphous phase refers to a value obtained by subtracting the sum total (% by mass) of the proportion of crystal content obtained by Rietveld analysis from 100% by mass.
• the average grain size of precipitated crystals is preferably 5 to 80 nm. From the viewpoint of improving transparency, the average grain size of precipitated crystals is preferably 80 nm or less, more preferably 70 nm or less, even more preferably 60 nm or less, even more preferably 50 nm or less, particularly preferably 40 nm or less, and most preferably 30 nm or less. . In order to increase the strength, the average grain size of the precipitated crystals is, for example, preferably 5 nm or more, more preferably 6 nm or more, even more preferably 7 nm or more, particularly preferably 8 nm or more, even more preferably 9 nm or more, and most preferably 10 nm or more. preferable.
• the average grain size of precipitated crystals is obtained from a transmission electron microscope (TEM) image.
• the average grain size of precipitated crystals can be estimated from scanning electron microscope (SEM) images.
• composition of crystallized glass is the same as the glass composition of the amorphous glass before crystallization in the production method described below. Therefore, the glass composition of the present crystallized glass and the glass composition of the amorphous glass have the same preferable aspects.
• the composition of the crystallized glass in this specification refers to the total composition of the crystal phase and the amorphous phase of the crystallized glass.
• the glass composition of the crystallized glass can be obtained by subjecting the crystallized glass to a heat treatment at a temperature equal to or higher than the melting point and analyzing the vitrified material. Analytical techniques include fluorescent X-ray analysis.
• the glass composition of the present crystallized glass is not particularly limited, an example of preferred embodiments is as follows. In the glass composition of the present crystallized glass, the preferred lower limit of the content of non-essential components is 0%.
• the present crystallized glass is preferably lithium aluminosilicate glass containing SiO2 , Al2O3 and Li2O .
• Lithium aluminosilicate glass contains lithium ions, which are alkali ions with the smallest ionic radius. Therefore, chemically strengthened glass having a favorable stress profile is easily obtained by chemical strengthening treatment in which ions are exchanged using various molten salts. .
• elements such as Na and Al having a valence close to that of Li should be included in the glass composition. is preferred.
• the glass composition of the present crystallized glass will be described in more detail below.
• SiO2 is a component that constitutes lithium disilicate-based crystals and is an essential component.
• SiO 2 is also a component that constitutes the network of glass, and is also a component that increases chemical durability.
• the content of SiO 2 is preferably 55-85%.
• the content of SiO 2 is preferably 55% or more, more preferably 57.5% or more, still more preferably 60% or more, from the viewpoint of depositing lithium disilicate-based crystals and improving chemical durability. .5% or more is more preferred, 65% or more is particularly preferred, 66% or more is even more preferred, 67% or more is even more preferred, 68% or more is even more preferred, 69% or more is particularly preferred, 70% or more is Most preferred.
• the content of SiO 2 is preferably 85% or less, more preferably 82.5% or less, still more preferably 80% or less, and even more preferably 79% or less, in order to improve meltability during glass production. , 78% or less is particularly preferred, 77% or less is even more preferred, 76% or less is even more preferred, 75% or less is even more preferred, and 74% or less is most preferred.
• Al 2 O 3 is an effective component from the viewpoint of improving the ion exchange performance during chemical strengthening and increasing the surface compressive stress after strengthening. Al 2 O 3 is also a component that improves chemical durability.
• Al is an element that can exist as a different element at the Li ion site of the lithium disilicate-based crystal.
• the content of Al 2 O 3 is preferably 1-5%.
• the content of Al 2 O 3 is preferably 1% or more, more preferably 1.5% or more, and even more preferably 2% or more in order to improve chemical durability and chemical strengthening characteristics. 2.5% or more is particularly preferred, 3% or more is more preferred, 3.5% or more is even more preferred, and 4% or more is most preferred.
• the content of Al 2 O 3 is preferably 5% or less, more preferably 4.9% or less, even more preferably 4.8% or less, and 4.7%.
• the following are particularly preferable, and 4.6% or less is more preferable.
• Li 2 O is a component that constitutes a lithium disilicate-based crystal and is an essential component.
• Li 2 O is a component that forms surface compressive stress by ion exchange, and is also a component that improves the meltability of the glass. Since the crystallized glass contains Li 2 O, the Li ions on the glass surface are ion-exchanged with Na ions, and the Na ions are ion-exchanged with K ions. You get a profile.
• the content of Li 2 O is preferably 15 to 25%.
• the content of Li 2 O is preferably 15% or more, more preferably 16% or more, even more preferably 17% or more, from the viewpoint of depositing lithium disilicate-based crystals and from the viewpoint of improving strength by chemical strengthening.
• the content of Li 2 O is preferably 25% or less, more preferably 24.5% or less, even more preferably 24% or less, and particularly preferably 23.5% or less. 23% or less is more preferable, and 22.5% or less is most preferable.
• Na 2 O and K 2 O are not essential components, but they are components that improve the meltability of the glass and also components that improve the ion exchange performance.
• the present crystallized glass may contain at least one of Na 2 O and K 2 O in order to obtain these effects.
• Na 2 O is a component that forms a surface compressive stress layer in chemical strengthening treatment using a potassium salt, and is a component that can improve the meltability of glass.
• Na is an element that can exist as a different element at the Li ion site of the lithium disilicate-based crystal.
• the content of Na 2 O is preferably 0 to 5.0%, more preferably 0.1 to 5.0%.
• the content is preferably 0.1% or more, more preferably 0.25% or more, even more preferably 0.5% or more, and 0.75% or more. Particularly preferred, 1.0% or more is more preferred, and 1.25% or more is most preferred.
• the content of Na 2 O is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, particularly preferably 3.5% or less. 0% or less is more preferred, and 2.5% or less is most preferred.
• K 2 O is a component that improves the meltability of the glass, and is also a component that improves the ion exchange performance.
• the content of K 2 O is preferably 0 to 5.0%.
• the content is preferably 0% or more, more preferably 0.1% or more, from the viewpoint of obtaining the effect.
• the content of K 2 O is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 3.5% or less, from the viewpoint of suppressing deterioration in chemical strengthening properties and chemical durability. 0% or less is more preferable, 2.5% or less is particularly preferable, 2.0% or less is even more preferable, 1.5% or less is even more preferable, 1.0% or less is even more preferable, and 0.5% % or less is most preferable.
• the total content of Na 2 O and K 2 O is preferably 0-10%.
• the total content of Na 2 O and K 2 O is determined from the viewpoint of improving the meltability of the glass and the viewpoint of improving the ion exchange performance. is preferably 0.2% or more, more preferably 0.25% or more, still more preferably 0.5% or more, even more preferably 0.75% or more, particularly preferably 1.0% or more, 1.25% more preferably 1.5% or more, most preferably 1.5% or more.
• the total content of Na 2 O and K 2 O is preferably 10% or less, more preferably 8% or less, and even more preferably 6% or less from the viewpoint of suppressing deterioration of chemical strengthening properties and chemical durability, 5% or less is particularly preferable, 4% or less is more preferable, and 3% or less is most preferable.
• the present crystallized glass may contain one or more selected from MgO, CaO, SrO and BaO.
• the total content of one or more selected from MgO, CaO, SrO and BaO is preferably 0-5.0%.
• the total of one or more selected from MgO, CaO, SrO and BaO is preferably 0% or more, more preferably 0.25% or more, and even more preferably 0.5% or more, 1.0% or more is particularly preferred, 1.25% or more is even more preferred, 1.5% or more is even more preferred, 1.75% or more is even more preferred, and 2.0% or more is most preferred.
• the total content of these is preferably 5.0% or less, more preferably 4.5% or less, and 4.0% or less from the viewpoint of applying sufficient compressive stress during chemical strengthening and from the viewpoint of improving radio wave transparency. is more preferable, 3.5% or less is particularly preferable, 3.0% or less is still more preferable, and 2.5% or less is most preferable.
• This crystallized glass may contain MgO in order to reduce the viscosity during melting.
• the content of MgO is preferably 0 to 5.0%.
• the content of MgO is preferably 0% or more, more preferably 0.25% or more, even more preferably 0.5% or more, and particularly preferably 1.0% or more. 1.25% or more is more particularly preferred, 1.5% or more is even more preferred, 1.75% or more is even more preferred, and 2.0% or more is most preferred.
• the content of MgO is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, and particularly 3.5% or less, from the viewpoint of suppressing deterioration in chemical strengthening properties. Preferably, 3.0% or less is more preferable, and 2.5% or less is most preferable.
• CaO is a component that improves the meltability of glass.
• the present crystallized glass may contain CaO.
• the content of CaO is preferably 0 to 5.0%.
• the content of CaO is preferably 0% or more, more preferably 0.25% or more, even more preferably 0.5% or more, and particularly preferably 1.0% or more. , more preferably 1.25% or more, more preferably 1.5% or more, even more preferably 1.75% or more, and most preferably 2.0% or more.
• the content of CaO is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, and particularly 3.5% or less from the viewpoint of suppressing deterioration in chemical strengthening properties.
• 3.0% or less is more preferable, and 2.5% or less is most preferable.
• the present crystallized glass may contain ZnO.
• the content of ZnO is preferably 0 to 5.0%.
• the content of ZnO is preferably 0% or more, more preferably 0.25% or more, even more preferably 0.5% or more, and particularly preferably 1.0% or more. 1.25% or more is more particularly preferred, 1.5% or more is even more preferred, 1.75% or more is even more preferred, and 2.0% or more is most preferred.
• the content of ZnO is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, particularly preferably 3.5% or less. 0% or less is more preferred, and 2.5% or less is most preferred.
• the total content of ZnO, SrO and BaO [ZnO] + [SrO] + [BaO] is preferably 0 to 5.0%.
• ZnO, SrO and BaO tend to deteriorate the chemical strengthening properties, so in order to facilitate chemical strengthening
• [ZnO] + [SrO] + [BaO] is preferably 5.0% or less, and 4.5 % or less, more preferably 4.0% or less, particularly preferably 3.5% or less, even more preferably 3.0% or less, most preferably 2.5% or less.
• the total content when these components are contained is preferably 0.1% or more, more preferably 0.3% or more, even more preferably 0.5% or more, and particularly 0.7% or more preferably 1.0% or more, more preferably 1.2% or more.
• P 2 O 5 is a component that becomes crystal nuclei of lithium disilicate-based crystals.
• the content of P 2 O 5 is preferably 0.5-5.0%.
• the content of P 2 O 5 is preferably 0.5% or more, more preferably 0.6% or more, still more preferably 0.7% or more, and 0.8% from the viewpoint of precipitating lithium disilicate-based crystals. % or more is particularly preferred, 0.9% or more is even more preferred, 1.0% or more is even more preferred, 1.1% or more is even more preferred, and 1.2% or more is most preferred.
• the content of P 2 O 5 is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, and particularly 3.5% or less, from the viewpoint of increasing acid resistance. preferably 3.0% or less, more preferably 2.5% or less, even more preferably 2.0% or less, most preferably 1.5% or less.
• TiO 2 is a component that can suppress the solarization of glass, but it is also a component that can serve as nuclei for other crystals.
• the content of TiO 2 is preferably 0-5.0%. From the viewpoint of suppressing excessive precipitation of other crystals, the content of TiO 2 is preferably 5.0% or less, more preferably 4.5% or less, particularly preferably 4.0% or less, and 3.5% or less. is more preferred, 3.0% or less is even more preferred, and 2.5% or less is most preferred.
• the crystallized glass may be substantially free of TiO2 . When the present crystallized glass contains TiO 2 , the content of TiO 2 is preferably 0.1% or more, more preferably 0.3% or more, even more preferably 0.5% or more, and 0.7%. 1.0% or more is more preferable, and 1.2% or more is most preferable.
• ZrO 2 is a component that can increase the surface compressive stress of chemically strengthened glass, but it is also a component that can serve as nuclei for other crystals such as petalite crystals.
• the content of ZrO 2 is preferably 0-5.0%. From the viewpoint of suppressing excessive precipitation of other crystals, the content of ZrO 2 is preferably 5.0% or less, more preferably 4.5% or less, further preferably 4.0% or less, and 3.5% or less. is more preferable, 3.0% or less is more preferable, 2.5% or less is particularly preferable, 2.0% or less is even more preferable, 1.8% or less is more preferable, 1.6% or less is even more Preferably, 1.4% or less is particularly preferred, and 1.2% or less is most preferred.
• the crystallized glass may be substantially free of ZrO2 .
• the content of ZrO 2 is preferably 0% or more, more preferably 0.1% or more, and still more preferably 0.2% or more from the viewpoint of reducing the crystal size. , more preferably 0.3% or more, particularly preferably 0.4% or more, even more preferably 0.5% or more, even more preferably 0.6% or more, even more preferably 0.7% or more, 1 0% or more is particularly preferred, and 1.1% or more is most preferred.
• the ratio of the total content of TiO 2 and ZrO 2 to the content of P 2 O 5 (TiO 2 +ZrO 2 )/P 2 O 5 is , 0 to 2.5.
• (TiO 2 +ZrO 2 )/P 2 O 5 is preferably 2.5 or less, more preferably 2.0 or less, even more preferably 1.8 or less, and 1 0.6 or less is particularly preferred, 1.4 or less is more preferred, and 1.2 or less is most preferred.
• TiO 2 +ZrO 2 )/P 2 O 5 is From the viewpoint of reducing the crystal size, it is preferably 0 or more, more preferably 0.1 or more, still more preferably 0.2 or more, particularly preferably 0.3 or more, further preferably 0.4 or more, and 0.5 or more. is much more preferable, and 0.6 or more is most preferable.
• B 2 O 3 is not an essential component, but it is a component that can reduce the brittleness of the glass and improve the crack resistance, and is a component that can improve the radio wave transmission.
• the present crystallized glass may contain B 2 O 3 .
• the content of B 2 O 3 is preferably 0 to 5.0%.
• the content is preferably 0.2% or more, more preferably 0.4% or more, still more preferably 0.6% or more, and 0.8% or more. Particularly preferred, 1.0% or more is more preferred, and 1.2% or more is most preferred.
• the content of B 2 O 3 is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, and particularly 3.5% or less, from the viewpoint of increasing acid resistance.
• 3.0% or less is more preferable, and 2.5% or less is most preferable.
• Nb 2 O 5 , Ta 2 O 5 , Gd 2 O 3 and CeO 2 are components that suppress solarization of glass and improve meltability.
• the present crystallized glass may contain at least one or more of these components.
• the total content of these components is preferably 0-3%.
• the total content is preferably 0.03% or more, more preferably 0.1% or more, still more preferably 0.3% or more, and particularly preferably 0. 0.5% or more, more preferably 0.8% or more, and most preferably 1% or more.
• the content of these is too large, it becomes difficult to increase the compressive stress value during the chemical strengthening treatment.
• the total content of these components is preferably 3% or less, more preferably 2.5% or less, still more preferably 2% or less, and particularly preferably 1.5%. or less, more preferably 1% or less, and most preferably 0.5% or less.
• Fe 2 O 3 is a component capable of improving the meltability of glass because it absorbs heat rays.
• the content of Fe 2 O 3 is preferably 0 to 0.3% by weight based on the oxide.
• the present crystallized glass preferably contains Fe 2 O 3 .
• the Fe 2 O 3 content is preferably 0.002% or more, more preferably 0.003% or more, still more preferably 0.005% or more, and particularly preferably 0.005% or more, in terms of weight percent based on the oxide. 007% or more, more preferably 0.008% or more, and most preferably 0.01% or more.
• Fe 2 O 3 is contained excessively, coloration occurs.
• the content is preferably 0.3% or less, more preferably 0.3% or less, based on the weight of oxides. 04% or less, more preferably 0.03% or less, particularly preferably 0.025% or less, still more preferably 0.02% or less, and most preferably 0.015% or less.
• the iron oxides in the glass are all Fe 2 O 3 , but in reality, Fe(III) in the oxidized state and Fe(II) in the reduced state are usually mixed. . Of these, Fe(III) produces a yellow coloration, Fe(II) produces a blue coloration, and the balance between the two produces a green coloration in the glass.
• the present crystallized glass may contain a coloring component within a range that does not impair the effects of the present invention.
• coloring components include Co3O4 , MnO2 , NiO, CuO, Cr2O3 , V2O5 , Bi2O3 , SeO2 , CeO2 , Er2O3 , Nd2O3 , and the like. are preferred.
• the content of the coloring components is preferably 5% or less in total, more preferably 4% or less, still more preferably 3% or less, and particularly preferably 2% or less, in terms of molar percentage based on oxides. Yes, more preferably 1% or less. If it is desired to increase the transmittance of the glass, it is preferable not to substantially contain these components.
• SO 3 chlorides, fluorides, and the like may be appropriately contained as clarifiers and the like when melting the glass.
• 2 O 3 is preferably not contained.
• Sb 2 O 3 When Sb 2 O 3 is contained, its content is preferably 0.3% or less, more preferably 0.1% or less, and most preferably not contained.
• preferred glass compositions of the present crystallized glass include, but are not limited to, the following.
• mole percentage display based on oxides SiO 2 55-85%, Al 2 O 3 1-5%, B2O3 0-5.0 %, P2O5 0.5-5.0 %, TiO 2 0-5.0%, ZrO 2 0-5.0%, Li 2 O 15-25%, Na 2 O 0-5.0% and K 2 O 0-5.0%, Crystallized glass containing 0 to 5.0% in total of one or more selected from MgO, CaO, SrO and BaO.
• the following glass composition is more preferable from the viewpoint of further improving the chemical strengthening properties and from the viewpoint of facilitating the presence of a different element in the Li ion site of the lithium disilicate-based crystal.
• mole percentage display based on oxides, SiO 2 55-85%, Al 2 O 3 1-5%, B2O3 0-5.0 %, P2O5 0.5-5.0 %, TiO 2 0-5.0%, ZrO 2 0-5.0%, Li 2 O 15-25%, Na 2 O 0.1-5.0% and K 2 O 0-5.0%, Crystallized glass containing 0 to 5.0% in total of one or more selected from MgO, CaO, SrO and BaO.
• the dielectric constant Dk of the present crystallized glass at 20° C. and 10 GHz is preferably 5.8 or less, more preferably 5.7 or less, even more preferably 5.6 or less, particularly preferably 5.5 or less, and 5.4. The following are more particularly preferred, 5.3 or less are more preferred, and 5.2 or less are most preferred. Since the loss of radio waves due to reflection on the glass surface can be suppressed when the dielectric constant Dk is small, the radio wave transmittance tends to be good. Although the lower limit of the dielectric constant Dk is not particularly limited, it is typically 4.0 or more. The dielectric constant Dk may be, for example, 4.0-5.8.
• the dielectric loss tangent tan ⁇ of the present crystallized glass at 20° C. and 10 GHz is preferably 0.01 or less, more preferably 0.009 or less, even more preferably 0.008 or less, particularly preferably 0.007 or less, and 0.006 or less. is more preferable, and 0.0055 or less is most preferable.
• the dielectric loss tangent tan ⁇ is small, the loss when radio waves pass through the inside of the glass can be suppressed, so that the radio wave transmittance tends to be good.
• the lower limit of the dielectric loss tangent is not particularly limited, it is typically 0.0005 or more.
• the dielectric loss tangent tan ⁇ may be, for example, 0.0005 to 0.01.
• the total value of the dielectric loss tangent tan ⁇ at 20° C. and 10 GHz of the present crystallized glass multiplied by 100 (tan ⁇ 100) and the dielectric constant Dk at 20° C. and 10 GHz is preferably 7.5 or less, and 7.25 or less. is more preferably 7.0 or less, even more preferably 6.75 or less, particularly preferably 6.5 or less, even more preferably 6.25 or less, even more preferably 6.0 or less, 5.9 or less is more preferred, and 5.8 or less is most preferred.
• This total value is a total value adjusted so that the relative permittivity Dk and the dielectric loss tangent tan ⁇ have the same degree of contribution.
• the radio wave transmittance is improved when the dielectric constant Dk and the dielectric loss tangent tan ⁇ are both small, it can be judged that the radio wave transmittance is better as the total value is smaller.
• the lower limit of the total value is not particularly limited, it is typically 4.5 or more. Such a total value may for example be between 4.5 and 7.5.
• dielectric constant and dielectric loss tangent at 20°C and 10 GHz are brought close to the values of dielectric constant and dielectric loss tangent at higher frequencies, respectively, and the frequency dependence (dielectric dispersion) is reduced, thereby improving the dielectric properties. It is preferable because the frequency characteristics are less likely to change, and the design change can be small even when the frequency in use is different.
• the crystals contained in the largest amount on a mass basis are lithium disilicate-based crystals, and in the lithium disilicate-based crystals, the proportion of Li ions occupying the Li ion sites is relatively small.
• °C and 10 GHz the dielectric constant Dk and the dielectric loss tangent tan ⁇ are small, and the radio wave transmission is excellent.
• the frequency dependence of the relative permittivity and dielectric loss tangent of glass is small. Excellent radio wave permeability even in the band.
• the dielectric constant and dielectric loss tangent can be measured using a network analyzer by the slip post dielectric resonance method (SPDR method).
• SPDR method slip post dielectric resonance method
• the present crystallized glass preferably has high transparency especially when used as a cover glass.
• the crystallized glass has a parallel light transmittance equivalent to a thickness of 0.7 mm, preferably 85% or more in the wavelength range of 400 nm to 1000 nm. Easy to see.
• Parallel light transmittance is more preferably 85.5% or more, still more preferably 86% or more, even more preferably 86.5% or more, particularly preferably 87% or more, even more particularly preferably 87.5% or more, 88% More preferably 88.5% or more, even more preferably 89% or more, especially preferably 89.5% or more, very preferably 90% or more, most preferably 90.5% or more.
• the parallel light transmittance is preferably as high as possible, but is typically preferably 98% or less, more preferably 96% or less, even more preferably 95% or less, particularly preferably 94% or less, and 93.5% or less. More preferably, 93% or less is even more preferable, and 92.5% or less is most preferable.
• the parallel light transmittance in terms of thickness of 0.7 mm may be, for example, 85 to 98%. If the crystallized glass having a thickness of 0.75 mm or more has a parallel light transmittance of 85% or more, the parallel light transmittance in terms of thickness of 0.7 mm is also considered to be 85% or more. In the case of crystallized glass having a plate thickness t greater than 0.7 mm, the parallel light transmittance may be actually measured after adjusting the plate thickness to 0.7 mm by polishing, etching, or the like.
• the present crystallized glass preferably has high transparency. Even if the thickness of the present crystallized glass is not 0.7 mm, the same applies. When used for the cover glass of the display, the screen of the display is easy to see.
• the plate thickness is preferably 0.7 mm or more, more preferably 0.8 mm or more, still more preferably 0.9 mm or more, still more preferably 1.0 mm or more, particularly preferably 1.2 mm or more, and still more preferably 1.0 mm or more.
• the parallel light transmittance is 85% or more when it is 5 mm or more, most preferably 2.0 mm or more. Chemically strengthened glass is generally used with a thickness of 2.0 mm or less.
• the haze value in terms of thickness of 0.7 mm is preferably less than 5%, more preferably 4% or less, still more preferably 3% or less, and even more preferably 2% or less in the wavelength range of 400 nm to 1000 nm.
• 1% or less is particularly preferred, 0.9% or less is even more preferred, 0.8% or less is more preferred, 0.7% or less is even more preferred, 0.6% or less is even more preferred, and 0.5%
• 0.4% or less being highly preferred, and 0.3% or less being most preferred.
• a smaller haze value is more preferable, but if the crystallinity is lowered or the crystal grain size is reduced in order to reduce the haze value, the mechanical strength tends to decrease.
• the haze value converted to a thickness of 0.7 mm is preferably 0.05% or more, more preferably 0.1% or more, even more preferably 0.15% or more, and 0.2%. % or more is particularly preferable, and 0.25% or more is more preferable.
• the haze value in terms of thickness of 0.7 mm may be, for example, 0.05% or more and less than 5%.
• the haze value is a value measured according to JIS K7136 (2000).
• X ⁇ Y represents "X Y ".
• the surface reflectance may be obtained by calculation from the refractive index, or may be actually measured.
• H 0.7 100 ⁇ [1 ⁇ (1 ⁇ H) ⁇ ((1 ⁇ R) 2 ⁇ T 0.7 )/((1 ⁇ R) 2 ⁇ T) ⁇ ][%]
• the plate thickness may be adjusted to 0.7 mm by polishing, etching, or the like, and the haze value may be actually measured.
• the Vickers hardness is preferably 600-1100. In order to increase wear resistance, the Vickers hardness is preferably 600 or higher, more preferably 650 or higher, still more preferably 700 or higher, particularly preferably 730 or higher, even more preferably 750 or higher, and most preferably 780 or higher.
• the Vickers hardness of crystallized glass is preferably 1100 or less, more preferably 1080 or less, even more preferably 1060 or less, particularly preferably 1050 or less, and even more preferably 1030 or less. Preferably, 1000 or less is most preferable.
• the Young's modulus of crystallized glass is preferably 85 to 130 GPa. Young's modulus is preferably 85 GPa or more, more preferably 90 GPa or more, still more preferably 93 GPa or more, particularly preferably 95 GPa or more, still more preferably 97 GPa or more, and most preferably 97 GPa or more, in order to suppress warpage due to strengthening during chemical strengthening. It is 100 GPa or more. Crystallized glass may be polished before use. For ease of polishing, the Young's modulus is preferably 130 GPa or less, more preferably 127 GPa or less, still more preferably 125 GPa or less, particularly preferably 123 GPa or less, and even more preferably 120 GPa or less.
• the fracture toughness value of the crystallized glass is preferably 0.8 MPa ⁇ m 1/2 or more, more preferably 0.83 MPa ⁇ m 1/2 or more, still more preferably 0.85 MPa ⁇ m 1/2 or more, and particularly preferably is 0.87 MPa ⁇ m 1/2 or more, and more preferably 0.9 MPa ⁇ m 1/2 or more, since fragments are less likely to scatter when broken when chemically strengthened.
• the upper limit of the fracture toughness value is not particularly limited, it is typically 1.5 MPa ⁇ m 1/2 or less.
• Fracture toughness values may be, for example, between 0.8 and 1.5 MPa ⁇ m 1/2 .
• the shape of the present crystallized glass is not particularly limited, it is preferably plate-like, for example.
• its plate thickness (t) is preferably 0.1 to 2 mm, for example.
• the plate thickness (t) is, for example, 2 mm or less, preferably 1.5 mm or less, more preferably 1 mm or less, and even more preferably 0.9 mm or less, from the viewpoint of enhancing the effect of chemical strengthening. , more preferably 0.8 mm or less, particularly preferably 0.7 mm or less, and most preferably 0.6 mm or less.
• the plate thickness is preferably 0.1 mm or more, more preferably 0.2 mm or more, and still more preferably 0.3 mm or more, from the viewpoint of obtaining a sufficient strength improvement effect by chemical strengthening treatment. , more preferably 0.35 mm or more, particularly preferably 0.4 mm or more, and even more preferably 0.5 mm or more.
• the shape of this crystallized glass may be other than a plate shape, depending on the product or application to which it is applied.
• the glass plate may have a fringing shape with a different outer peripheral thickness.
• the form of the glass plate is not limited to this, and for example, the two main surfaces may not be parallel to each other. Also, one or both of the two main surfaces may be curved in whole or in part. More specifically, the glass plate may be, for example, a flat glass plate without warping, or a curved glass plate having a curved surface.
• a chemically strengthened glass according to an embodiment of the present invention (hereinafter also referred to as “the present chemically strengthened glass”) is obtained by chemically strengthening the above-mentioned present crystallized glass. That is, the base composition of the present chemically strengthened glass is the same as the glass composition of the above-described present crystallized glass, and the preferred composition range is also the same.
• the chemically strengthened glass is plate-shaped, for example, the content ratio of the alkali metal element differs between the surface layer and the center in the thickness direction.
• the glass composition in the deepest part from the surface of the chemically strengthened glass is the same as the parent composition of the chemically strengthened glass, except when extreme ion exchange treatment is performed.
• the chemically strengthened glass is tabular, the deepest portion from the glass surface is, for example, half the thickness t.
• the present chemically strengthened glass is, for example, a chemically strengthened glass having a compressive stress layer on the surface, a surface compressive stress value CS of 50 MPa or more, and is preferably chemically strengthened glass that is the above-described present crystallized glass.
• the strength can be improved by chemically strengthening this crystallized glass.
• the crystals contained in the chemically strengthened glass, the content thereof, and the ratio of Li ions occupying the Li ion sites of the lithium disilicate-based crystals, except for the case where extreme ion exchange treatment etc. It is considered to be similar to glass. That is, the present chemically strengthened glass is excellent in radio wave transmission for the same reason as the present crystallized glass. In addition, this chemically strengthened glass is excellent in both strength and radio wave transparency.
• the present chemically strengthened glass preferably has a surface compressive stress value CS of 50 to 400 MPa.
• CS is preferably 50 MPa or more, more preferably 60 MPa or more, still more preferably 70 MPa or more, even more preferably 80 MPa or more, particularly preferably 90 MPa or more, even more preferably 100 MPa or more, and even more preferably 110 MPa or more. It is preferably 130 MPa or more, more preferably 150 MPa or more, and most preferably 150 MPa or more.
• the surface compressive stress value CS is preferably 400 MPa or less, more preferably 350 MPa or less, even more preferably 300 MPa or less, particularly preferably 250 MPa or less, still more preferably 225 MPa or less, and most preferably 200 MPa or less.
• the compressive stress value CS50 at a depth of 50 ⁇ m from the surface is preferably 5 to 100 MPa.
• CS50 is preferably 5 MPa or higher, more preferably 10 MPa or higher, particularly preferably 15 MPa or higher, even more preferably 20 MPa or higher, and most preferably 25 MPa or higher.
• CS50 is large, chemically strengthened glass is less likely to break when damaged due to dropping or the like.
• CS 50 is preferably 100 MPa or less, more preferably 90 MPa or less, even more preferably 80 MPa or less, particularly preferably 70 MPa or less, even more preferably 60 MPa or less, even more preferably 50 MPa or less, and 40 MPa.
• Most preferred are:
• the internal tensile stress value CT of this chemically strengthened glass is preferably 5 to 100 MPa.
• CT is preferably 100 MPa or less, more preferably 75 MPa or less, even more preferably 50 MPa or less, particularly preferably 40 MPa or less, still more preferably 30 MPa or less, and most preferably 20 MPa or less.
• a small CT makes it difficult for crushing to occur.
• the internal tensile stress value CT is preferably 5 MPa or more, more preferably 10 MPa or more, particularly preferably 15 MPa or more, and still more preferably 17.5 MPa or more. When the CT is equal to or higher than the above value, the compressive stress in the vicinity of the surface increases and the strength increases.
• the compressive stress layer depth DOL of this chemically strengthened glass is preferably 0.04t to 0.22t with respect to the thickness t (mm).
• DOL is preferably 0.22t or less, more preferably 0.21t or less, even more preferably 0.20t or less, and 0.19t or less because if it is too large with respect to the thickness t (mm), the CT will increase.
• Particularly preferred is 0.18t or less, more preferred is 0.16t or less, even more preferred is 0.14t or less, and most preferred is 0.12t or less.
• DOL is preferably 0.04 t or more, more preferably 0.05 t or more, particularly preferably 0.06 t or more, further preferably 0.07 t or more, and even more preferably 0.08 t or more.
• the DOL is preferably 63 ⁇ m or less, more preferably 56 ⁇ m or less, and even more preferably 49 ⁇ m or less. Also, DOL is preferably 28 ⁇ m or more, more preferably 35 ⁇ m or more, and particularly preferably 42 ⁇ m or more.
• the preferred plate thickness (t) and preferred shape of the chemically strengthened glass are the same as the preferred plate thickness (t) and shape of the present crystallized glass described above.
• the present chemically strengthened glass can be produced by chemically strengthening the present crystallized glass described above. Further, the present crystallized glass can be produced by heat-treating amorphous glass to crystallize it.
• Amorphous glass can be produced, for example, by the following method.
• the manufacturing method described below is an example of manufacturing plate-like crystallized glass and chemically strengthened glass.
• Glass raw materials are blended so as to obtain a glass having a preferred composition, and heated and melted in a glass melting furnace. Thereafter, the molten glass is homogenized by bubbling, stirring, addition of a clarifier, etc., formed into a glass plate having a predetermined thickness by a known forming method, and slowly cooled. Alternatively, the molten glass may be formed into a block, cooled slowly, and then cut into a plate.
• the preferable glass composition of the amorphous glass is the same as the preferable glass composition of the crystallized glass described above.
• Crystallized glass is obtained by heat-treating the amorphous glass obtained by the above procedure.
• the method of heat treatment is not particularly limited as long as it includes at least one step of heat treatment of the amorphous glass.
• Heat treatment is preferably performed by, for example, the following method.
• the temperature is raised from room temperature to a first treatment temperature T1 and held for a certain period of time (holding time t1), and then held at a second treatment temperature T2 higher than the first treatment temperature for a certain period of time (holding time t2).
• T1 first treatment temperature
• T2 higher than the first treatment temperature for a certain period of time
• holding time t2 holding time
• a two-stage heat treatment may be maintained by a two-stage heat treatment.
• a one-step heat treatment of cooling to room temperature after holding at a specific treatment temperature may be used.
• the first treatment temperature T1 is preferably in a temperature range in which the crystal nucleation rate increases in the glass composition, and the second treatment temperature T2 is in the glass composition in which the crystal growth rate increases.
• a temperature range is preferred.
• the retention time t1 at the first treatment temperature T1 is preferably relatively long so that a sufficient number of crystal nuclei are generated. By generating a large number of crystal nuclei, the size of each crystal is reduced, and highly transparent crystallized glass can be easily obtained.
• the first treatment temperature T1 is preferably 450° C. to 700° C.
• the holding time t1 is preferably 1 hour to 6 hours.
• the second treatment temperature is preferably 600° C. to 800° C.
• the holding time t2 is preferably 1 hour to 6 hours.
• the method for relatively reducing the proportion of Li ions in the Li ion sites of the lithium disilicate-based crystal is not particularly limited, but a method that satisfies at least one of the following first and second conditions is preferable.
• heat treatment is preferably performed at a relatively low temperature.
• the temperature of the heat treatment in each stage is preferably 750 ° C. or lower, more preferably 740 ° C. or lower, and even more preferably 730 ° C. or lower. ° C. or less is particularly preferred.
• the preferable lower limit of the heat treatment temperature is the same as described above.
• the heating rate to each treatment temperature is preferably 0.5 to 100° C./min.
• the heating rate is preferably 0.5°C/min or more, more preferably 1°C/min or more, still more preferably 2°C/min or more, particularly preferably 3°C/min or more, and still more preferably 4°C/min or more. , 5° C./min or more is most preferred.
• the heating rate is preferably 100° C./min or less, more preferably 75° C./min or less, even more preferably 50° C./min or less, and particularly 25° C./min or less. preferable.
• the temperature increase rate of at least a part of the heat treatment is within the above range, and more preferably that all the temperature increase rates are within the above range.
• Preferred aspects of the rate of temperature drop from each treatment temperature are the same as the preferred aspects of the rate of temperature increase.
• the molten glass may be homogenized and formed into a glass plate with a predetermined thickness, or the molten glass may be formed into a block and subsequently subjected to continuous crystallization.
• setter plates When heat-treating plate-shaped glass, examples of setter plates include silicon carbide plates, silicon nitride plates, SiN plates, alumina plates, mullite cordierite plates, mullite plates, and crystallized glass plates. In addition, a material having high thermal conductivity is preferable in order 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, still more preferably 40 W/(m ⁇ K) or more.
• a release agent can be used to prevent the glass from sticking to the setter plate.
• release agents include alumina cloth and glass cloth.
• powdery boron nitride, alumina, minerals, and the like can be used.
• the powder release agent may be mixed with a solvent and applied by spraying or the like.
• the average particle size is preferably 80 ⁇ m or less, more preferably 50 ⁇ m or less, and even more preferably 30 ⁇ m or less.
• heat-treating glass When heat-treating glass, it may be laminated to improve work efficiency. When laminating, it is preferable to use a release agent between glasses. Also, a setter plate may be placed between the glasses.
• the crystallized glass obtained by the above procedure is ground and polished as necessary to form a crystallized glass plate.
• a crystallized glass plate is cut into a predetermined shape and size or chamfered, if the cutting or chamfering is performed before the chemical strengthening treatment, the compressive stress will also be applied to the end face due to the subsequent chemical strengthening treatment. It is preferred because layers are formed.
• metal ions with a small ionic radius in the glass are removed by contacting the glass with a metal salt, such as by immersing the glass in a melt of a metal salt containing metal ions with a large ionic radius (e.g., potassium nitrate). is replaced with a metal ion having a large ionic radius.
• a metal salt containing metal ions with a large ionic radius e.g., potassium nitrate
• the metal ions with a small ionic radius are typically Na ions or Li ions.
• Large ionic radius metal ions are typically Na ions or K ions, more specifically Na ions or K ions for Li ions, and K ions for Na ions. is.
• Li-Na exchange which exchanges Li ions in the glass with Na ions.
• Na--K exchange in which Na ions in the glass are exchanged for K ions.
• molten salts for chemical strengthening include nitrates, sulfates, carbonates, and chlorides.
• nitrates include lithium nitrate, sodium nitrate, potassium nitrate, cesium nitrate, and silver nitrate.
• Sulfates include, for example, lithium sulfate, sodium sulfate, potassium sulfate, cesium sulfate, and silver sulfate.
• Carbonates include, for example, lithium carbonate, sodium carbonate, potassium carbonate and the like.
• Chlorides include, for example, lithium chloride, sodium chloride, potassium chloride, cesium chloride, and silver chloride. These molten salts may be used alone, or may be used in combination.
• the time and temperature can be selected in consideration of the glass composition and the type of molten salt.
• the present crystallized glass is preferably chemically strengthened at 450° C. or less for one hour or less.
• a molten salt containing preferably 0.3% by mass of Li and 99.7% by mass of Na is preferably 0
• a treatment of immersion for about 5 hours can be mentioned.
• the chemical strengthening treatment may be, for example, a two-stage ion exchange as follows.
• the present crystallized glass is preferably immersed in a metal salt containing Na ions (eg, sodium nitrate) at about 350 to 500° C. for about 0.1 to 10 hours.
• a metal salt containing Na ions eg, sodium nitrate
• ion exchange occurs between Li ions in the crystallized glass and Na ions in the metal salt, forming a relatively deep compressive stress layer.
• a metal salt containing K ions eg, potassium nitrate
• K ions eg, potassium nitrate
• a large compressive stress is generated in the compressive stress layer formed by the previous process, for example, within a depth of about 10 ⁇ m.
• a stress profile with a large surface compressive stress value is likely to be obtained.
• the present invention relates to an electronic device comprising the present crystallized glass or the present chemically strengthened glass described above. That is, since the present crystallized glass and the present chemically strengthened glass can achieve both high strength and radio wave transparency, they are useful as cover glasses and circuit substrates used in electronic devices.
• the present crystallized glass and the present chemically strengthened glass are particularly useful as cover glasses used in mobile devices such as mobile phones, smart phones, personal digital assistants (PDAs), and tablet terminals.
• the present crystallized glass and the present chemically strengthened glass are not intended to be portable, but are used for cover glass of display devices such as televisions (TVs), personal computers (PCs), and touch panels, walls of elevators, and buildings such as houses and buildings. Wall surfaces (full-screen displays), building materials such as window glass, table tops, interiors of automobiles and airplanes, etc., and cover glass for them, as well as applications such as cases with curved surfaces that are not flat due to bending or molding. Useful.
• Glass raw materials were prepared so as to have the composition shown in Table 1 as a molar percentage based on oxides, and weighed to give 400 g of glass. Next, the mixed raw materials were placed in a platinum crucible, placed in an electric furnace at 1500° C. to 1700° C., melted for about 3 hours, degassed, and homogenized.
• the obtained molten glass was poured into a metal mold, held at a temperature about 50°C higher than the glass transition point for 1 hour, and then cooled to room temperature at a rate of 0.5°C/min to obtain a glass block.
• the obtained glass block was cut, ground, and finally mirror-polished on both sides to obtain glass plates having a thickness of 2 mm (amorphous glass 1 to amorphous glass 9).
• Heat treatment was performed on each of the obtained amorphous glasses. That is, the above amorphous glasses 1 to 9 were first heated to the first treatment temperature T1 at the heating rate shown in Table 2. Then, the first-stage heat treatment was performed by holding at the first treatment temperature T1 for the holding time t1. Crystal nuclei are formed throughout the volume of the starting glass by the first-stage heat treatment. After the first-stage heat treatment, the precursor (amorphous glass after the first-stage heat treatment) was heated to the second treatment temperature T2 at the heating rate shown in Table 2. Then, the second-stage heat treatment was performed by holding the second treatment temperature T2 for the holding time t2. Crystals grow by the heat treatment in the second stage, and the crystallization rate increases. After that, the temperature was lowered to room temperature at the temperature lowering rate shown in Table 2.
• the crystallized glasses of Examples 1 to 9 were obtained by heat-treating the amorphous glasses shown in Table 1 under the conditions shown in Table 2. Further, the physical properties shown in Table 2 were obtained from the obtained crystallized glass.
• the crystallized glasses of Examples 1 to 7 are examples, and the crystallized glasses of Examples 8 and 9 are comparative examples.
• the method for measuring each physical property is shown below. (Measurement of haze value and parallel light transmittance)
• the obtained amorphous glass and crystallized glass were processed into a rectangular parallelepiped having a length of 30.0 mm, a width of 30.0 mm and a thickness of 0.7 mm, and the surfaces of 30.0 mm ⁇ 30.0 mm were mirror-polished. It was measured using a haze meter HZ-V3 manufactured by Suga Test Instruments Co., Ltd.
• the crystallized glass was processed into a rectangular parallelepiped having a length of 30.0 mm, a width of 30.0 mm, and a thickness of 0.5 mm, and the surface of 30.0 mm ⁇ 30.0 mm was mirror-polished.
• the dielectric constant Dk and the dielectric loss tangent tan ⁇ at 20° C. and 10 GHz were measured by the slip post dielectric resonance method (SPDR method).
• each crystallized glass was immersed in a salt of 100% sodium nitrate at 450° C. for 1 hour for chemical strengthening.
• the surface compressive stress value CS and compressive stress depth DOL after chemical strengthening were measured using a scattered light photoelastic stress meter SLP-1000 manufactured by Orihara Seisakusho Co., Ltd.
• PXRD measurement of crystallized glass The obtained crystallized glass was subjected to PXRD measurement according to the following procedure to identify the crystal species.
• PXRD measurement sample preparation conditions The crystallized glass plate subjected to the SPDR method was pulverized using an agate mortar and an agate pestle to obtain a powder for PXRD measurement.
• PXRD measurement conditions Powder X-ray diffraction was measured under the following conditions to identify precipitated crystals. Diffraction peak patterns recorded in the ICSD inorganic crystal structure database and the ICDD powder diffraction database were used to identify the crystal species.
• the powder X-ray diffraction profile obtained under the above conditions was analyzed using the Rietveld analysis program: Rietan FP.
• the analysis of each sample was converged so that Rwp, which indicates the convergence of the analysis, was 10 or less.
• the Rietveld method is described in "Crystal Analysis Handbook” Edited by the Crystallographic Society of Japan, “Crystal Analysis Handbook” (Kyoritsu Shuppan, 1999, pp. 492-499).
• the precipitated crystal ratio in the table is the precipitated ratio (content ratio) of each crystal calculated using the Rietveld analysis and expressed as a mass percentage with respect to the total amount of the crystallized glass. Further, the "percentage of Li ions occupying Li ion sites" represents the percentage of Li ions occupying Li ion sites in the lithium disilicate-based crystal.
• CS and DOL in the table respectively represent the surface compressive stress value CS and compressive stress depth DOL of the chemically strengthened glass subjected to the chemical strengthening described above for each crystallized glass.
• the proportion of Li ions in the Li ion sites of the lithium disilicate-based crystals is less than 95%.
• the crystallized glasses of Examples 1 to 7 had a total value of 100 times the dielectric constant Dk and the dielectric loss tangent tan ⁇ at 20° C. and 10 GHz in the samples after crystallization, which was very good, being 7.5 or less. It was confirmed that it has a good radio wave transparency.
• a compressive stress of 50 MPa or more was applied to the surface layers of the crystallized glasses of Examples 1 to 7 by chemical strengthening. That is, the crystallized glasses of Examples 1 to 7 are also excellent in chemical strengthening properties, and can be given high strength by chemical strengthening.
• the proportion of Li ions in the Li ion sites in the lithium disilicate crystal was 100.0%.
• the sum of the value obtained by multiplying the dielectric constant Dk and the dielectric loss tangent tan ⁇ by 100 at 20° C. and 10 GHz in the sample after crystallization was a very large value exceeding 7.5. , and is inferior in terms of radio wave transparency.
• the crystals contained in the largest amount on a mass basis are lithium disilicate-based crystals, Crystallized glass, wherein the ratio of Li ions to Li ion sites in the lithium disilicate-based crystal is less than 95%.
• the crystallized glass according to 1 above which has a light transmittance of 85% or more in a wavelength range of 400 nm to 1000 nm in terms of a thickness of 0.7 mm.
• Crystallized glass according to any one of 1 to 5 above containing 0 to 5.0% in total of 0 to 5.0% of K 2 O and one or more selected from MgO, CaO, SrO and BaO. 7. In mole percentage display based on oxides, Na 2 O 0.1-5.0% 7. Crystallized glass according to 6 above. 8. 8. The method for producing crystallized glass according to any one of 1 to 7 above, subjecting the amorphous glass to at least one step of heat treatment; The temperature of the heat treatment is all 750 ° C. or less, In each of the heat treatments, the rate of temperature increase to the treatment temperature and the rate of temperature decrease from the treatment temperature are both 0.5 ° C./min or more. A method for producing crystallized glass. 9.
• a chemically strengthened glass having a compressive stress layer on the surface The surface compressive stress value is 50 MPa or more, Chemically strengthened glass, which is the crystallized glass according to any one of 1 to 7 above. 10. 9. The chemically strengthened glass according to 9 above, which is plate-shaped and has different proportions of alkali metal elements between the surface layer and the center in the thickness direction. 11. 11. An electronic device comprising the crystallized glass described in any one of 1 to 7 above or the chemically strengthened glass described in 9 or 10 above.
• This crystallized glass and this chemically strengthened glass are useful as cover glasses and circuit substrates used in electronic devices because they can achieve both high strength and high radio wave transparency due to chemical strengthening.
• the present crystallized glass and the present chemically strengthened glass are particularly useful as cover glasses used in mobile devices such as mobile phones, smart phones, personal digital assistants (PDAs), and tablet terminals.
• construction such as cover glass of display devices such as television (TV), personal computer (PC), touch panel etc., elevator wall surface, wall surface of building such as house and building (full display), window glass etc. It is also useful as materials, table tops, interiors of automobiles, airplanes, etc. and cover glass for them, and also for applications such as cases having curved surfaces that are not plate-shaped by bending or molding.

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