Glass and glass articles with high chemical tempering properties and low susceptibility to crystallization, as well as manufacturing processes

Abstract

This disclosure relates to glass, glass articles and their uses, processes for the manufacture of glass and glass articles, processes for the chemical tempering of a glass article, and products containing or consisting of glass or glass articles of the type described herein. The glasses are characterized by very good chemical temperability combined with a low tendency to crystallize.

Description

[0001] This disclosure relates to glass, glass articles and their uses, processes for the manufacture of glass and glass articles, processes for the chemical tempering of a glass article, and products that contain or consist of glass or glass articles of the type described herein.

[0002] Glass used for display covers, for example in smartphones or tablet computers, must meet a number of requirements. For instance, it must exhibit good mechanical stability and be economical to manufacture. For mechanical stability, it is important that the glass can be chemically tempered effectively. During chemical tempering, smaller ions on the surface and to a certain depth within the glass are replaced by larger ones. This creates a compressive stress on the surface, which improves mechanical stability, such as fracture toughness, edge strength, and puncture resistance.

[0003] The requirements for glass used in flexible and foldable displays are particularly high. This glass must be able to withstand high compressive stress values, even at very low thicknesses. At the same time, it should be suitable for cost-effective manufacturing processes such as down draw or overflow fusion (also known as "slot down draw" or "overflow down draw"). Appropriate viscosity profiles and crystallization resistance are essential for these processing properties.

[0004] There is a need for glass compositions, articles and processes that can generate particularly high compressive stresses even with small glass thicknesses and enable the most economical production possible. Summary of Revelation

[0005] In a first aspect, this disclosure concerns a glass that is free of As2O3 and Sb2O3, comprising in mol%: from until SiO2 50,0 70,0 Al2O3 > 10,0 14,5 B2O3 0,0 5,0 Li2O 0,0 5,0 Na2O > 14,0 25,0 K2O 0,0 5,0 MgO 0,0 6,0 CaO 0,0 5,0 ZnO 0,0 5,0 ZrO2 0,0 3,0 where the stoichiometric ratio Na2O / Al2O3 is from 1.35 to 1.75 and the stoichiometric ratio SiO2 / (Al2O3+ZrO2) is from 3.00 to 4.90.

[0006] In a second aspect, this disclosure relates to a glass comprising the components SiO2, Al2O3 and Na2O, and optionally ZrO2, wherein the molar ratio of Na2O / Al2O3 is from 1.35 to 1.75 and / or wherein the molar ratio of SiO2 / (Al2O3+ZrO2) is from 3.00 to 4.90.

[0007] In a third aspect, this disclosure concerns a glass with a low-temperature preload value (LTT). 200µm of at least 1150 MPa, a low-temperature bias value LTT 30µm of at least 800 MPa and / or a crystal growth rate of 10 5 dPa*s of less than 0.50 µm / min.

[0008] In a fourth aspect, this revelation concerns a glass with a low-temperature diffusion capacity D. LT of at least 4.0 µm 2 / h and / or a crystal growth rate at 10 5 dPa*s of less than 0.50 µm / min.

[0009] In a fifth aspect, this disclosure relates to a glass article made of the glass according to one of the first four aspects, in particular a glass article having a thickness of less than 300 µm and / or a compressive stress on at least one surface of at least 800 MPa.

[0010] In a sixth aspect, this disclosure relates to an electronic device having at least one display and a display cover, wherein the display cover comprises or consists of glass or a glass article according to any of the first five aspects.

[0011] In a seventh aspect, this revelation concerns a process for making a glass, encompassing the following steps: - Providing glass raw materials suitable for obtaining a glass according to one of the first four aspects, - Melting the glass raw materials into a glass melt, - optional shaping of the molten glass into a glass article, - Cooling of the molten glass or, optionally, the glass article.

[0012] In an eighth aspect, this invention relates to a method for chemically tempering a glass article consisting of a glass according to the first four aspects, comprising the steps: - Placing the glass article in an ion exchange bath, - Exchanging ions to be exchanged from the glass article for ions from the ion exchange bath at an ion exchange temperature, wherein the ions of the ion exchange bath have at least partially a larger ion diameter than the ions to be exchanged from the glass article, where the ion exchange temperature is 300°C to 500°C. Brief description of the illustrations Fig.show microphotographs of glass samples according to embodiments of this disclosure at 100x magnification after heat treatment. Fig. shows a microphotograph of a glass sample according to a comparison example at 100x magnification after heat treatment. Detailed description Definitions

[0013] “T4” is the temperature at which the glass has a viscosity of 10 4 dPa*s has. T4 can be measured using methods known to those skilled in the art for determining the viscosity of glass, e.g., according to ISO 7884-2:1987-12. “T 13 “ is the temperature at which the glass has a viscosity of 10 13 dPa*s. Similarly, others refer to T n The specified temperatures refer to the temperature at which the glass has a viscosity of 10 n dPa*s. “T5”, for example, is the temperature at which the glass has a viscosity of 10 5 dPa*s has. The lower cooling point (“strain point”, T14,5 The viscosity point (η) is defined as the temperature at which all movements of the glass molecules have reached a point where no further strain can be introduced into the hot glass. This is a viscosity fixed point (temperature value) at a viscosity η = 10⁻⁶. 14,5 dPa*s. This limit value typically represents the highest operating temperature of a glass component. “T g “ is the transformation temperature according to ISO 7884-8:1987.

[0014] The Vogel-Fulcher-Tammann equation (VFT) is generally used to calculate the temperature required to achieve a specific viscosity of a glass (see the ISO 7884 series of standards, e.g., ISO 7884-1:1987-12, 7884-2:1987-12; 7884-3:1987-12; 7884-4:1987-12): igη=A+BT−T0

[0015] In the VFT equation, η is the viscosity, A and B are material parameters, T is the temperature, and T0 is the Vogel temperature. A, B, and T0 are constant for a given glass. Specifying these constants provides more accurate information about the viscosity behavior of a particular glass composition.

[0016] Three-point bending strength is a test of a material's bending strength. It can be determined using the method described in ASTM C1161-13. An example test setup is as follows: Cylindrical steel bearings with a radius of 2 mm; span of 16 mm; specimens measuring 28 x 28 x 0.2 mm. 3 ; prepared according to standard procedure 7.2.4; loading rate 5 mm / min.

[0017] Vickers hardness is determined using a standard Vickers indenter according to ASTM C 1327 (2015). The following parameters are used: force F n(max) = 1 N; Approach speed = 4 µm / min; Loading rate 2 N / min; Holding time 20 s; Unloading rate 6 N / min.

[0018] The main surfaces of a glass article are the two surfaces with the largest areas of all surfaces of the glass article.

[0019] When this disclosure refers to the glass being "free from" or not containing a particular component, this means that the component may only be present in the glass as an impurity. This means that it is not added in substantial quantities. Substances considered insubstantial include less than 1000 ppm (by weight), less than 750 ppm (by weight), less than 500 ppm (by weight), less than 250 ppm (by weight), and in particular, less than 100 ppm (by weight).

[0020] The liquidus temperature is the temperature above which no crystals form in a glass melt of a given composition; that is, no crystallization is possible. The liquidus viscosity is the viscosity of a glass melt at its liquidus temperature. The upper devitrification limit (UEL) is used synonymously with the liquidus temperature in this disclosure.

[0021] The glasses described here are preferably producible by drawing. "Producible by drawing" refers in particular to manufacturing processes for thin glass (< 2.0 mm) and ultra-thin glass (< 200 µm) such as down draw, e.g., with glass thicknesses of 75 µm and less. This means that the glass possesses the properties necessary for processing by drawing, in particular a crystal growth rate within the viscosity range important for the manufacturing process, which corresponds to a viscosity of 10 5 dPa*s includes the crystal growth rate at 10 5dPa*s should be particularly smaller than 0.50 µm / min so that the glass can be processed into thin glass and ultra-thin glass using the down draw method.

[0022] Crystal growth rate (KWR in µm / min) is a measure of a glass's resistance to devitrification. It is measured at a viscosity of 10 5The crystal growth rate is determined in dPa*s. The lower the crystal growth rate, the higher the devitrification resistance and the less waste can be produced. This allows the manufacturing process to be stabilized and carried out continuously. The measurement of the crystal growth rate is well-established. The crystal growth rate is determined by thermally treating the glass under investigation, in the form of individual glass grains with a diameter of 2 mm to 3 mm, for 16 hours in a gradient furnace on a platinum support with an increasing temperature regime. The crystal growth rate is observed and measured microscopically along the formed crystals, i.e., at their greatest extent. At a viscosity of 10 5 Since no devitrification occurs at all, a crystal growth rate of 10 dPa*s is possible. 5The dPa*s value cannot be determined, which is indicated here as 0 µm / min. The duration of 16 hours takes into account the fact that the residence time of the molten glass in the drawing process at this temperature can be of this order of magnitude.

[0023] The "coefficient of thermal expansion" or "CTE" is the mean linear coefficient of thermal expansion in a temperature range of 20 °C to 300 °C. It is determined according to DIN ISO 7991:1987.

[0024] In this description, "prestressable" or "chemically prestressable" means that the material or article so designated can be chemically prestressed. For this to occur, it must possess exchangeable ions that can be replaced by ions with larger radii. Sodium ions are an example of exchangeable ions. Glasses that do not contain alkali metal ions are considered non-prestressable within the scope of this disclosure. A material or article that is prestressable is not (yet) prestressed but can be subjected to such a process.

[0025] Compressive stress (CS) is the compression introduced into the glass network at the surface of a glass article, for example, through chemical prestressing. The compressive stress typically decreases with increasing distance from the prestressed surface towards the bulk material. It is common practice, and will be used here as well, for the specified compressive stress to refer to the maximum value at the described surface. Commercially available measuring instruments can be used to measure compressive stress, such as the FSM6000LE or the SLP1000 (both from Orihara Industrial Co. Ltd., Tokyo, Japan).

[0026] The depth of the ion-exchanged layer, extending from the surface of a glass article into its volume, is referred to as the DoL (depth of layer) in this disclosure. It is usually expressed in micrometers. This quantity is familiar to those skilled in the art. It can be determined using commercially available measuring instruments, such as the FSM6000 (Luceo Co., Ltd., Tokyo, JP).

[0027] Diffusivity (D in µm) 2 / h) is a material property of a temperable glass that describes its ability to form an ion-exchanged layer during chemical tempering / ion exchange. This property can be calculated by examining the depth of the ion-exchanged layer (DoL in µm) after an ion exchange following a specific ion exchange time (IET in hours). The higher the diffusivity, the deeper the DoL after a given ion exchange time. The corresponding formula is: D=DoL27.84⋅IET. Unless otherwise stated, the value of D in this description refers to chemical prestressing with potassium nitrate (100%) for 30 minutes. For very thin glass (especially below 100 µm), the duration of chemical prestressing may be reduced, e.g., to 10 minutes. The temperature for this measurement is 440 °C. Unless otherwise stated herein, the diffusivity refers to a sample with a thickness of 200 µm.

[0028] In addition to diffusivity, this description also includes low-temperature diffusivity (D). LT in µm 2 / h). It is a measure of the property of a temperable glass to assume a compressive stress at a low tempering temperature. The tempering process is energy-intensive, as it must be carried out at temperatures of at least 300 °C. Reducing the tempering temperature has the advantage of reducing energy consumption. The D LT The diffusion capacity is determined in the same way as the previously described test, but at a lower temperature (390 °C) and for a slightly longer duration. The test duration is 45 minutes, although for very thin glass (especially below 100 µm) the chemical prestressing time can be reduced, e.g., to 20 minutes. Unless otherwise specified herein, the diffusion capacity refers to a sample with a thickness of 200 µm.

[0029] The low temperature toughening value is 200 µm (low temperature toughening) LTT 200µmThis denotes the degree of compressive stress CS in megapascals that can be achieved for a temperable glass or glass article within the framework of a low-temperature tempering protocol for a glass thickness of 200 µm. A glass or glass article with a high low-temperature tempering value can therefore be chemically tempered effectively at low temperatures. The low-temperature tempering protocol corresponds to the one described above for low-temperature diffusion capacity D. LT The described procedure, namely 100% KNO3, 390 °C, 45 minutes, results in the following value: middle temperature toughening (MTT) at 200 µm. 200µm the magnitude of the compressive stress CS in megapascals that can be achieved for a temperable glass or temperable glass article for a glass thickness of 200 µm within the framework of a tempering protocol, as described above for diffusion capability.

[0030] The low temperature toughening value is 30 µm (LTT). 30µm This refers to the degree of compressive stress CS in megapascals that can be achieved for a temperable glass or glass article with a glass thickness of 30 µm under a low-temperature tempering protocol. A glass or glass article with a high low-temperature tempering value can therefore be chemically tempered effectively at low temperatures. The low-temperature tempering protocol corresponds to the one described above for low-temperature diffusion capacity D. LT The described procedure, namely 100% KNO3, 390 °C, 20 minutes, results in a medium temperature toughening value of 30 µm (MTT). 30µmthe magnitude of the compressive stress CS in megapascals that can be achieved for a temperable glass or temperable glass article for a glass thickness of 200 µm within the framework of a tempering protocol, as described above for diffusion capability.

[0031] This description uses a key figure, the "flexible display suitability score" (FDSS), to assess the suitability of a glass for the economical production of glass articles for flexible displays. This score is calculated from the LTT (Laser Temperature Test). 200µm and the KWR as follows: LTT200μmKWR=FDSS

[0032] A glass is particularly suitable for the economical production of glass articles for flexible displays if its FDSS value is greater than 30,000. If the KWR cannot be determined due to insufficient crystallization tendency, this value is given as >100,000. For clarity, the unit MPa*min / µm is omitted from the FDSS value.

[0033] Central tension (CT): When CS is induced on one or both sides of a glass article, a tensile stress must be induced in the central region of the glass to compensate for the tension, according to Newton's third law. This stress is called the "central tension." CT can be calculated from the measured values ​​CS and DoL using the following formula (where t is the glass thickness). CT=CS∗DoLt−2∗DoL

[0034] The term "roughness" used here refers to the average roughness R. a, which is a measure of the quality of a surface. Typically, amplitude parameters characterize the surface based on the vertical deviations of the roughness profile from the center line. R a This is the arithmetic mean of the absolute values ​​of these vertical deviations. The value can be determined according to DIN EN ISO 4287:2010-07.

[0035] Unless otherwise stated, “cooling” in the context of this description includes both active cooling, for example using a cooling fluid (e.g., air or water), and passive cooling.

[0036] The glass described herein has particular advantages when used in glass articles of very low thickness. Glass articles according to this disclosure can be so thin that they are bendable or even foldable. A glass article is considered "bendable" if it can be bent to a bending radius of up to 25 mm without failure. A glass article is considered "foldable" if it can be bent to a bending radius of up to 5 mm without failure. Some glass articles of this disclosure can be bent to bending radii significantly less than 5 mm.

[0037] The statement that a glass article "can be bent to a bending radius of X mm without failing" or that the glass article has a "bending radius of X mm" means that the glass article will not break when bent 180° between two parallel Bakelite plates to the specified bending radius. Unless otherwise stated, the test is carried out at a temperature of 25°C and a relative humidity of 30%. Glass

[0038] The glass described in this disclosure can be called aluminosilicate glass, meaning it contains silicon dioxide and aluminum oxide as components. To enable chemical tempering (synonym: "chemical prestressing"), the glass also contains an interchangeable component, in this case, the sodium ion in sodium oxide. Furthermore, the glass can include other components to achieve or enhance specific properties. From the inventors' perspective, it is particularly surprising that glasses capable of being prestressed to such high stress values ​​can be produced within the composition range discussed here. Generally, the achievable prestress of a glass article decreases with decreasing thickness. In other words, a thin glass article can only be chemically prestressed to lower compressive stress values ​​than a thicker article.It is relatively easy to temper a conventional aluminosilicate display glass to tensile strengths exceeding 1000 MPa if the glass is over 300 µm thick. This is more difficult for very thin glasses, such as foldable glass with thicknesses of, for example, 25 µm to 75 µm. While methods exist to increase the temperability of glass, such as increasing the Al₂O₃ and ZrO₂ content, these measures increase the glass's tendency to crystallize, particularly in the viscosity range of approximately 10, which is crucial for down-draw forming. 5 dPa*s. Development efforts in the glass industry are enormous in order to meet the electronics industry's need for highly resistant and bendable or even foldable glass products.

[0039] Optionally, the glass consists essentially of the components described herein, i.e., it may be free of other components not discussed herein.

[0040] Preferably the glass comprises the components SiO2, Al2O3 and Na2O and optionally ZrO2, wherein the stoichiometric ratio Na2O / Al2O3 is from 1.35 to 1.75 and / or the stoichiometric ratio SiO2 / (Al2O3+ZrO2) is from 3.00 to 4.90.

[0041] In one embodiment, the Na₂O / Al₂O₃ stoichiometric ratio is at least 1.10, at least 1.20, at least 1.30, at least 1.35, or at least 1.36. In another embodiment, the Na₂O / Al₂O₃ stoichiometric ratio is at least 1.37, at least 1.38, at least 1.39, or at least 1.40. The Na₂O / Al₂O₃ stoichiometric ratio can be limited to at most 1.75, at most 1.73, at most 1.65, at most 1.60, at most 1.55, or at most 1.50. Thus, the Na₂O / Al₂O₃ stoichiometric ratio can be 1.10 to 1.75, 1.20 to 1.73, 1.30 to 1.65, 1.35 to 1.60, 1.39 to 1.55, or 1.40 to 1.50. In one embodiment, this ratio is 1.36 to 1.75, 1.37 to 1.73, 1.38 to 1.65, or 1.39 to 1.60.

[0042] In one embodiment, the stoichiometric ratio SiO2 / (Al2O3+ZrO2) is at least 2.50, at least 3.00, at least 3.30, or at least 3.50. In another embodiment, the stoichiometric ratio SiO2 / (Al2O3+ZrO2) is at least 4.00, at least 4.40, or at least 4.50. The stoichiometric ratio SiO2 / (Al2O3+ZrO2) can be limited to at most 5.50, at most 5.00, at most 4.90, at most 4.80, or at most 4.60. Thus, the stoichiometric ratio SiO2 / (Al2O3+ZrO2) can be from 2.50 to 5.50, from 3.00 to 5.00, from 3.30 to 4.90, from 3.50 to 4.80, or from 4.00 to 4.60. In one embodiment, this ratio is from 3.00 to 4.90, from 3.30 to 4.90, from 3.50 to 4.80, or from 4.00 to 4.80.

[0043] According to this disclosure, the glass contains SiO2, in particular in a content of at least 50.0 mol% and / or at most 70.0 mol%. In one embodiment, the SiO2 content in the glass is at least 53.0 mol%, at least 55.0 mol%, at least 57.5 mol%, at least 60.0 mol%, or at least 61.5 mol%. Optionally, the SiO2 content in the glass can be up to 68.0 mol%, up to 66.0 mol%, up to 65.0 mol%, or up to 64.0 mol%. In another embodiment, the SiO2 content is from 50.0 mol% to 70.0 mol%, from 53.0 mol% to 68.0 mol%, from 55.0 mol% to 66.0 mol%, from 57.5 mol% to 65.0 mol%, or from 60.0 mol% to 64.0 mol%.

[0044] According to this disclosure, the glass contains Al₂O₃, in particular in a content of at least >10.0 mol% and / or at most 14.5 mol%. In one embodiment, the Al₂O₃ content in the glass is at least 10.5 mol%, at least 11.0 mol%, at least 11.5 mol%, at least 12.0 mol%, or at least 13.2 mol%. Optionally, the Al₂O₃ content in the glass can be up to 18.0 mol%, up to 17.0 mol%, up to 16.0 mol%, or up to 14.5 mol%. Optionally, the Al₂O₃ content is up to 14.3 mol%, up to 14.0 mol%, up to 13.5 mol%, or up to 13.0 mol%. In one embodiment, the Al₂O₃ content is >10.0 mol% to 18.0 mol%, 10.5 mol% to 17.0 mol%, 11.0 mol% to 16.0 mol%, 11.5 mol% to 14.5 mol%, or 12.0 mol% to 14.0 mol%. Optionally, the Al₂O₃ content can be 11.5 mol% to 14.5 mol%, 12.0 mol% to 13.5 mol%, or 12.0 mol% to 13.0 mol%. In one embodiment, the Al₂O₃ content is more than 14.0 mol%.

[0045] According to this disclosure, the glass may contain B₂O₃, in particular in a content of up to 5.0 mol%. In one embodiment, the B₂O₃ content in the glass is at least 0.1 mol%, at least 0.5 mol%, at least 1.0 mol%, at least 2.0 mol%, or at least 3.0 mol%. Optionally, the B₂O₃ content in the glass may be up to 3.0 mol%, up to 2.0 mol%, or up to 1.5 mol%. In another embodiment, the B₂O₃ content is from 0.0 mol% to 5.0 mol%, from 0.0 mol% to 3.0 mol%, from 0.1 mol% to 5.0 mol%, from 1.0 mol% to 5.0 mol%, or from 3.0 mol% to 5.0 mol%. Optionally, the B₂O₃ content may be from 0.0 mol% to 1.5 mol%, or the glass may be free of B₂O₃.

[0046] According to this disclosure, the glass may contain Li₂O, in particular in a concentration of up to 5.0 mol%, up to 2.5 mol%, or up to 1.0 mol%. Optionally, the Li₂O content may be from 0.0 mol% to 5.0 mol%, from 0.0 mol% to 1.0 mol%, or the glass may be free of Li₂O.

[0047] According to this disclosure, the glass contains Na₂O, in particular in a concentration of >14.0 mol%, >14.5 mol% and / or at most 25.0 mol%. In one embodiment, the Na₂O content in the glass is at least 15.5 mol%, at least >16.0 mol%, at least 17.0 mol%, at least 17.5 mol%, at least 18.0 mol% or at least 19.0 mol%. Optionally, the Na₂O content in the glass can be up to 22.0 mol%, up to 21.0 mol%, up to 20.0 mol% or up to 19.0 mol%. In one embodiment, the Na2O content is from >14.0 mol% to 25.0 mol%, from >16.0 mol% to 22.0 mol%, from 17.5 mol% to 21.0 mol%, from 17.5 mol% to 20.0 mol% or from 17.5 mol% to 19.0 mol%.

[0048] According to this disclosure, the glass may contain K₂O, in particular in a concentration of up to 5.0 mol%. In one embodiment, the K₂O content in the glass is at least 0.1 mol%, at least 0.3 mol%, at least 0.5 mol%, or at least 0.7 mol%. Optionally, the K₂O content in the glass may be up to 3.0 mol%, up to 2.0 mol%, up to 1.5 mol%, or up to 1.0 mol%. In another embodiment, the K₂O content is from 0.0 mol% to 5.0 mol%, from 0.0 mol% to 3.0 mol%, from 0.1 mol% to 3.0 mol%, from 0.3 mol% to 1.5 mol%, or from 0.5 mol% to 1.0 mol%. Optionally, the K₂O content may be from 0.0 mol% to 1.5 mol%, or the glass may be free of K₂O.

[0049] The stoichiometric ratio of the components K₂O / Na₂O can be, in particular, at least 0.00 and / or at most 0.20. For example, this ratio can be at least 0.01, at least 0.02, or at least 0.03. Optionally, it is at most 0.12 or at most 0.08. In one embodiment, the stoichiometric ratio of the components K₂O / Na₂O is from 0.01 to 0.20, from 0.02 to 0.12, or from 0.03 to 0.08.

[0050] According to this disclosure, the glass may contain MgO, in particular in a concentration of at least 0.0 mol% and / or at most 6.0 mol%. In one embodiment, the MgO content in the glass is at least 0.5 mol%, at least 1.0 mol%, at least 2.0 mol%, at least 3.0 mol%, or at least 3.5 mol%. Optionally, the MgO content in the glass may be up to 5.5 mol%, up to 5.0 mol%, up to 4.5 mol%, or up to 4.0 mol%. In another embodiment, the MgO content is from 0.0 mol% to 6.0 mol%, from 0.0 mol% to 3.0 mol%, from 1.0 mol% to 5.0 mol%, from 2.0 mol% to 5.0 mol%, or from 3.5 mol% to 4.5 mol%.

[0051] In one embodiment of this disclosure, the components SiO2, Al2O3, Na2O, ZrO2 and MgO together represent at least 95.0 mol%, at least 96.0 mol% or at least 97.0 mol% of the composition of the glass.

[0052] According to this disclosure, the glass may contain CaO, in particular in a concentration of up to 5.0 mol%. In one embodiment, the CaO content in the glass is at least 0.0 mol%, at least 0.1 mol%, at least 0.5 mol%, at least 1.0 mol%, or at least 1.4 mol%. Optionally, the CaO content in the glass may be up to 3.0 mol%, up to 2.0 mol%, or up to 1.5 mol%. In another embodiment, the CaO content is from 0.0 mol% to 5.0 mol%, from 0.0 mol% to 3.0 mol%, from 0.1 mol% to 5.0 mol%, from 1.0 mol% to 5.0 mol%, or from 1.0 mol% to 3.0 mol%. Optionally, the CaO content may be from 0.5 mol% to 1.5 mol%, or the glass may be free of CaO.

[0053] According to this disclosure, the glass may contain SrO, in particular in a content of up to 4.0 mol%, up to 2.0 mol%, or up to 1.0 mol%. Optionally, the SrO content may be from 0.0 mol% to 2.0 mol%, from 0.0 mol% to 1.0 mol%, or the glass may be free of SrO.

[0054] According to this disclosure, the glass may contain BaO, in particular in a content of up to 4.0 mol%, up to 2.0 mol%, or up to 1.0 mol%. Optionally, the BaO content may be from 0.0 mol% to 2.0 mol%, from 0.0 mol% to 1.0 mol%, or the glass may be free of BaO.

[0055] The sum of the alkaline earth metal oxide contents in the glass is abbreviated as "R'O". The alkaline earth metal oxides are, in particular, MgO, CaO, BaO, and SrO. R'O is preferably at least 0.0 mol%, at least 1.0 mol%, at least 2.0 mol%, or at least 3.0 mol%. Optionally, this sum is at most 10.0 mol%, at most 8.0 mol%, at most 7.0 mol%, at most 6.0 mol%, or at most 5.0 mol%. In one embodiment, R'O is from 0.0 mol% to 10.0 mol%, from 1.0 mol% to 8.0 mol%, or from 2.0 mol% to 6.0 mol%.

[0056] The stoichiometric ratio of the components MgO / R'O can be, in particular, at least 0.40 and / or at most 1.00. For example, this ratio can be at least 0.50, at least 0.75, or at least 0.90. Optionally, it is at most 0.75. In one embodiment, the stoichiometric ratio of the components MgO / R'O is from 0.40 to 1.00, from 0.50 to 1.00, or from 0.90 to 1.00.

[0057] In one embodiment, the sum of the components Al₂O₃ and R'O is at least 14.0 mol% and / or <20.0 mol%. Optionally, this sum is at least 15.0 mol%, at least 15.5 mol%, or at least 16.0 mol%. It can be up to 20.0 mol%, up to 19.0 mol%, <18.0 mol%, up to 17.5 mol%, or up to 17.0 mol%. In another embodiment, the sum of the components Al₂O₃ and R'O lies in the range of 14.0 mol% to 20.0 mol%, 14.0 mol% to <18.0 mol%, or 15.0 mol% to 17.5 mol%.

[0058] The abbreviation "R₂O" denotes the sum of the alkali metal oxide contents in the glass. The alkali metal oxides are, in particular, Li₂O, Na₂O, K₂O, and Cs₂O. R₂O preferably amounts to at least >14.0 mol%, at least 15.0 mol%, at least 16.0 mol%, or at least 17.0 mol%. Optionally, this sum amounts to at most 30.0 mol%, at most 26.0 mol%, at most 24.0 mol%, at most 22.0 mol%, or at most 20.0 mol%. In one embodiment, R₂O amounts to 14.0 mol% to 30.0 mol%, 16.0 mol% to 24.0 mol%, or 17.0 mol% to 20.0 mol%.

[0059] The stoichiometric ratio of the components MgO / R₂O can be, in particular, at least 0.10 and / or at most 0.50. For example, this ratio can be at least 0.12, at least 0.14, or at least 0.16. Optionally, it is at most 0.30, at most 0.25, or at most 0.22. In one embodiment, the stoichiometric ratio of the components MgO / R₂O is from 0.10 to 0.30, from 0.12 to 0.25, or from 0.14 to 0.22.

[0060] According to this disclosure, the glass may contain ZnO, in particular in a concentration of up to 5.0 mol%. In one embodiment, the ZnO content in the glass is at least 0.0 mol%, at least 0.1 mol%, at least 1.0 mol%, or at least 2.0 mol%. Optionally, the ZnO content in the glass may be up to 3.0 mol%, up to 2.8 mol%, or up to 1.0 mol%. In another embodiment, the ZnO content is from 0.0 mol% to 5.0 mol%, from 0.0 mol% to 3.0 mol%, from 0.1 mol% to 3.0 mol%, or from 1.0 mol% to 3.0 mol%. Optionally, the ZnO content may be from 2.0 mol% to 3.0 mol%, or from 0.0 to 1.0 mol%, or the glass may be free of ZnO.

[0061] According to this disclosure, the glass may contain ZrO2, in particular in a concentration of at least 0.0 mol% and / or at most 3.0 mol%. In one embodiment, the ZrO2 content in the glass is at least 0.1 mol%, at least 0.3 mol%, at least 0.5 mol%, at least 0.6 mol%, or at least 1.0 mol%. Optionally, the ZrO2 content in the glass may be up to 2.5 mol%, up to 2.0 mol%, up to 1.7 mol%, or up to 0.8 mol%. In another embodiment, the ZrO2 content is from 0.0 mol% to 3.0 mol%, from 0.0 mol% to 2.0 mol%, from 0.3 mol% to 2.5 mol%, from 0.5 mol% to 2.0 mol%, or from 0.5 mol% to 1.7 mol%.

[0062] In one embodiment, the sum of the components Al₂O₃ and ZrO₂ is at least 11.0 mol% and / or at most 17.0 mol%. Optionally, this sum is at least 12.0 mol%, at least 12.5 mol%, or at least 13.0 mol%. It can be up to 16.0 mol%, up to 15.0 mol%, or up to 14.0 mol%. In another embodiment, the sum of the components Al₂O₃ and ZrO₂ lies in the range of 11.0 mol% to 17.0 mol%, 12.0 mol% to 16.0 mol%, or 12.5 mol% to 15.0 mol%.

[0063] The stoichiometric ratio of the components ZrO2 / Al2O3 can be, in particular, at least 0.01 and / or at most 0.20. For example, this ratio can be at least 0.03 or at least 0.04. Optionally, it is at most 0.17, at most 0.15, at most 0.11, or at most 0.08. In one embodiment, the stoichiometric ratio of the components ZrO2 / Al2O3 is from 0.01 to 0.17, from 0.03 to 0.11, or from 0.03 to 0.08.

[0064] The stoichiometric ratio of the components ZrO₂ / R'O can be, in particular, at least 0.10 and / or at most 0.50. For example, this ratio can be at least 0.12 or at least 0.14. Optionally, it is at most 0.45, at most 0.40, at most 0.35, or at most 0.20. In one embodiment, the stoichiometric ratio of the components ZrO₂ / R'O is from 0.10 to 0.50, from 0.12 to 0.35, or from 0.14 to 0.20.

[0065] According to this disclosure, the glass may contain fluorine (F), in particular in a concentration of up to 1.0 mol%. In one embodiment, the concentration of F in the glass is at least 0.1 mol%, at least 0.3 mol%, or at least 0.4 mol%. Optionally, the concentration of F in the glass may be up to 1.0 mol%, up to 0.8 mol%, up to 0.7 mol%, or up to 0.6 mol%. In another embodiment, the concentration of F is from 0.0 mol% to 1.0 mol%, from 0.0 mol% to 0.8 mol%, from 0.1 mol% to 1.0 mol%, from 0.3 mol% to 1.0 mol%, or from 0.4 mol% to 0.8 mol%. Optionally, the fluorine content may be from 0.4 mol% to 0.6 mol%, or the glass may be free of F. In this description, the fluorine content is expressed as the amount of substance F (not F2).

[0066] According to this disclosure, the glass may contain chlorine (CI), in particular in a concentration of up to 1.0 mol%. In one embodiment, the CI content in the glass is at least 0.1 mol%, at least 0.2 mol%, or at least 0.3 mol%. Optionally, the CI content in the glass may be up to 1.0 mol%, up to 0.8 mol%, up to 0.7 mol%, or up to 0.6 mol%. In another embodiment, the CI content is from 0.0 mol% to 1.0 mol%, from 0.0 mol% to 0.8 mol%, from 0.1 mol% to 1.0 mol%, from 0.2 mol% to 1.0 mol%, or from 0.4 mol% to 0.8 mol%. Optionally, the chlorine content may be from 0.4 mol% to 0.6 mol%, or the glass may be free of CI.

[0067] Optionally, the glass may contain P₂O₅. Typically, the P₂O₅ content will be limited to a maximum of 1.0 mol%, in particular to a maximum of 0.8 mol%, <0.5 mol%, or <0.2 mol%. In one embodiment, the glass is free of P₂O₅.

[0068] The glass composition may include one or more refining agents to remove bubbles from the melt during production. However, the two components known to be toxic, As₂O₃ and Sb₂O₃, are preferably omitted. In other words, the glass is preferably free of As₂O₃ and / or Sb₂O₃. In one embodiment, the glass is also free of other components known to be harmful to health, such as, in particular, the oxides of lead, cadmium, and chromium. The glass may also be free of TiO₂. The glass may contain SnO₂. In some embodiments, its content is limited to a maximum of 0.5 mol%, 0.3 mol%, 0.2 mol%, or 0.1 mol%.

[0069] In one embodiment, the glass can contain color-imparting ions such as iron, cobalt, chromium, copper, vanadium, nickel, manganese, neodymium, erbium, europium, or molybdenum, or combinations thereof. These can be used in their various oxidation states. Optionally, the glass can contain one or more color components, in particular Fe₂O₃, CoO, and / or Cr₂O₃.

[0070] In one embodiment, the glass comprises in mol%: from until SiO2 50,0 70,0 Al2O3 > 10,0 14,5 Na2O > 14,0 25,0 MgO 0,0 6,0 ZrO2 0,0 3,0 R2O >14,0 30,0 R'O 0,0 10,0

[0071] In one embodiment, the glass comprises in mol%: from until SiO2 55,0 65,0 Al2O3 11,5 14,5 Na2O > 16,0 22,0 MgO 1,0 5,0 ZrO2 0,0 2,0 R2O >16,0 24,0 R'O 1,0 8,0

[0072] In one embodiment, the glass comprises in mol%: from until SiO2 57,5 65,0 Al2O3 11,5 13,5 Na2O > 16,0 20,0 MgO 3,0 5,0 ZrO2 0,5 2,0 R2O >16,0 22,0 R'O 3,0 7,0

[0073] In one embodiment, the glass comprises in mol%: from until SiO2 60,0 64,0 Al2O3 12,0 13,5 Na2O 17,0 19,0 K2O 0,3 1,5 MgO 3,0 5,0 ZrO2 0,5 1,7

[0074] In one embodiment, the glass comprises in mol%: from until SiO2 50,0 70,0 Al2O3 > 10,0 14,5 B2O3 0,0 5,0 Li2O 0,0 5,0 Na2O > 14,0 25,0 K2O 0,0 5,0 MgO 0,0 6,0 CaO 0,0 5,0 ZnO 0,0 5,0 ZrO2 0,0 3,0

[0075] In one embodiment, the glass comprises in mol%: from until SiO2 50,0 70,0 Al2O3 > 10,0 14,5 B2O3 0,0 5,0 Li2O 0,0 5,0 Na2O > 14,0 25,0 K2O 0,0 5,0 MgO 0,0 6,0 CaO 0,0 5,0 SrO 0,0 4,0 BaO 0,0 4,0 ZnO 0,0 5,0 ZrO2 0,0 3,0

[0076] In one embodiment, the glass comprises in mol%: from until SiO2 55,0 65,0 Al2O3 11,5 14,5 B2O3 0,0 3,0 Li2O 0,0 1,0 Na2O > 16,0 22,0 K2O 0,0 3,0 MgO 1,0 5,0 CaO 0,0 3,0 ZnO 0,0 3,0 ZrO2 0,0 2,0

[0077] In one embodiment, the glass comprises in mol%: from until SiO2 55,0 65,0 Al2O3 11,5 14,5 B2O3 0,0 3,0 Li2O 0,0 1,0 Na2O > 16,0 22,0 K2O 0,0 3,0 MgO 1,0 5,0 CaO 0,0 3,0 SrO 0,0 2,0 BaO 0,0 2,0 ZnO 0,0 3,0 ZrO2 0,0 2,0

[0078] In one embodiment, the glass comprises in mol%: from until SiO2 57,5 65,0 Al2O3 11,5 13,5 B2O3 0,0 1,5 Li2O 0,0 1,0 Na2O > 16,0 20,0 K2O 0,0 1,5 MgO 3,0 5,0 CaO 0,0 1,5 SrO 0,0 1,0 BaO 0,0 1,0 ZnO 0,0 1,0 ZrO2 0,3 2,0

[0079] In one embodiment, the glass comprises in mol%: from until SiO2 60,0 64,0 Al2O3 12,0 13,5 Na2O 17,0 19,0 K2O 0,3 1,5 MgO 3,0 5,0 CaO 0,0 1,5 SrO 0,0 1,0 BaO 0,0 1,0 ZnO 0,0 1,0 ZrO2 0,3 1,7 where the glass is optionally free of B2O3, P2O5 and / or Li2O.

[0080] In one embodiment, the glass has a low-temperature prestress value LTT. 200µm of at least 1150 MPa, at least 1200 MPa, at least 1250 MPa, or at least 1300 MPa. Optionally, the low-temperature bias value is up to 1600 MPa, up to 1500 MPa, up to 1400 MPa, or up to 1375 MPa. The LTT 200µm In particular, it can range from 1150 MPa to 1600 MPa, from 1200 MPa to 1500 MPa or from 1250 MPa to 1400 MPa.

[0081] In one embodiment, the glass has a mid-temperature prestress value MTT. 200µmof at least 1100 MPa, at least 1200 MPa, at least 1225 MPa, or at least 1250 MPa. Optionally, the mean temperature bias value is up to 1500 MPa, up to 1400 MPa, up to 1350 MPa, or up to 1300 MPa. The MTT 200µm In particular, it can range from 1100 MPa to 1500 MPa, from 1200 MPa to 1400 MPa or from 1200 MPa to 1350 MPa.

[0082] In one embodiment, the glass has a low-temperature prestress value LTT. 30µm of at least 800 MPa, at least 850 MPa, at least 900 MPa, or at least 950 MPa. Optionally, the low-temperature preload value LTT is... 30µm Up to 1400 MPa, up to 1300 MPa, up to 1100 MPa, or up to 1000 MPa. The LTT 30µm In particular, it can range from 800 MPa to 1400 MPa, from 900 MPa to 1300 MPa or from 950 MPa to 1100 MPa.

[0083] In one embodiment, the glass has a mid-temperature prestress value MTT. 30µmof at least 700 MPa, at least 750 MPa, at least 800 MPa, or at least 900 MPa. Optionally, the mean temperature bias value (MTT) is... 30µm Up to 1300 MPa, up to 1200 MPa, up to 1100 MPa, or up to 950 MPa. The MTT 30µm In particular, it can range from 700 MPa to 1300 MPa, from 800 MPa to 1200 MPa or from 900 MPa to 1100 MPa.

[0084] In one embodiment, the glass has a crystal growth rate of 10 5 dPa*s of less than 0.50 µm / min, less than 0.20 µm / min, less than 0.10 µm / min, less than 0.05 µm / min or less than 0.02 µm / min.

[0085] In one embodiment, the glass exhibits a low-temperature diffusion capacity D LT of at least 4.0 µm 2 / h, at least 8.0 µm 2 / h, at least 10.0 µm 2 / h, at least 12.0 µm 2 / h or at least 14.0 µm 2 / h on. Optionally, D is LT at most 100 µm 2 / h, at most 80 µm 2 / h, at most 60 µm 2 / h, at most 40 µm 2 / h, at most 25 µm 2 / h or at most 20 µm 2 / h. In one embodiment, the D is LT of 4.0 µm 2 / h up to 100 µm 2 / h, from 8.0 µm 2 / h up to 60 µm 2 / h, from 10.0 µm 2 / h up to 40 µm 2 / h or from 14.0 µm 2 / h up to 25 µm 2 / h.

[0086] In one embodiment, the glass has a diffusion capacity D of at least 20.0 µm. 2 / h, at least 25.0 µm 2 / h, at least 30.0 µm 2 / h or at least 40.0 µm 2 / h. Optionally, D is at most 300 µm. 2 / h, at most 200 µm 2 / h, at most 150 µm 2 / h, at most 100 µm 2 / h, at most 80 µm 2 / h or at most 70 µm 2 / h. In one embodiment, D is 20.0 µm 2 / h up to 300 µm 2 / h, from 25.0 µm2 / h up to 200 µm 2 / h, from 25.0 µm 2 / h up to 100 µm 2 / h or from 30.0 µm 2 / h up to 80 µm 2 / h.

[0087] The glass can have a modulus of elasticity (“Young's modulus”) of at least 70 GPa, at least 71 GPa, at least 72 GPa, or at least 73 GPa. Optionally, the modulus of elasticity can be up to 80 GPa, up to 78 GPa, or up to 76 GPa. In certain embodiments, the modulus of elasticity of the glass is between 70 GPa and 80 GPa, between 71 GPa and 78 GPa, or between 72 GPa and 76 GPa. The glass of this disclosure can have a modulus of elasticity (in GPa) between 73 and 75. An excessively high modulus of elasticity can reduce the bendability of a glass article made from the glass.

[0088] In one embodiment, the mean coefficient of thermal expansion CTE can be at least 8.50, at least 8.75, at least 9.0, at least 9.25 or at least 9.5.

[0089] The glass is preferably well-suited for the cost-effective production of glass articles for flexible displays. In particular, it has an FDSS value of more than 20,000, more than 30,000, more than 40,000, more than 50,000, or more than 60,000. Optionally, this value can even be more than 65,000 or more than 100,000. Glass items

[0090] A glass article as defined in this disclosure may have a thickness of 1,000 µm or less and be made of glass as described herein. Generally, the glass article may be referred to as a thin glass article or a glass sheet. It may have a thickness of less than 850 µm, less than 500 µm, less than 300 µm, less than 200 µm, or less than 100 µm. In some embodiments, the thickness may be 80 µm or less, or 70 µm or less. Some articles have a thickness of 50 µm or less, or 40 µm or less. For a foldable glass article, the desired thickness may be less than 100 µm, less than 80 µm, less than 60 µm, or less than 40 µm. A minimum thickness may be required to ensure that the glass article is sufficiently impact-resistant. The minimum thickness can be at least 5 µm, at least 10 µm, at least 15 µm or at least 20 µm.

[0091] In particular, the glass article may have a thickness of 1,000 µm or less, at least in certain sections, and be made of glass as described herein. It may have a thickness of less than 850 µm, less than 500 µm, less than 300 µm, less than 200 µm, or less than 100 µm, at least in certain sections. In some embodiments, the thickness may be 80 µm or less, or 70 µm or less, at least in certain sections. Some articles have a thickness of 50 µm or less, or 40 µm or less, at least in certain sections. For a foldable glass article, the desired thickness may be less than 100 µm, less than 80 µm, less than 60 µm, or less than 40 µm, at least in certain sections. A minimum thickness may be required to ensure sufficient impact resistance of the glass article. The minimum thickness can be at least 5 µm, at least 10 µm, at least 15 µm or at least 20 µm in at least some sections.In this context, "at least in sections" means that the glass article has portions with the specified thickness. For example, the glass article may be bendable or foldable and, for this purpose, may have a bending area where the bending takes place. This bending area may be thinner than other sections of the glass article. In this way, the advantages of particularly thin glass sections (bending) and somewhat thicker glass sections (mechanical stability) can be combined. In one embodiment, the glass article has a bending area in which the glass article has a thickness of less than 100 µm, less than 80 µm, less than 60 µm, or less than 40 µm. In another embodiment, the thickness in the bending area is at least 10 µm or at least 20 µm. Outside the bending area, the glass article may have a thickness of more than 100 µm, in particular at least 150 µm or at least 200 µm.In one embodiment, the thickness of the glass article outside the bending area is at least twice as large or at least three times as large as the smallest thickness inside the bending area.

[0092] The glass item can have a surface area of ​​at least 10 cm² 2 , at least 15 cm 2 or at least 20 cm 2 In some embodiments, the article may have an area of ​​less than 10,000 cm². 2 , less than 1,000 cm 2 or less than 200 cm 2 have.

[0093] The glass article may have a surface roughness R on one or both of its main surfaces. aThe roughness of the glass should be no more than 5.0 nm, 3.0 nm, or 1.5 nm. This very low roughness can be achieved through a down-draw process. Such exceptionally smooth surfaces are obtained when the glass is allowed to flow smoothly without contact with a shaping surface before solidifying. Experts refer to these as "fire-polished surfaces." Mechanically polished surfaces have lower roughness values. Furthermore, polishing marks are visible on mechanically polished surfaces under atomic force microscopy (AFM). Additionally, residues of the mechanical polishing compound, such as diamond powder, iron oxide, and / or CeO2, can also be detected under AFM. Since mechanically polished surfaces must always be cleaned after polishing, certain ions are leached from the glass surface. This depletion of specific ions can be detected using time-of-flight (ToF) mass spectrometry (SIMS).Examples of such ions are Ca, Zn, Ba and alkali metals.

[0094] The glass article can have a Vickers hardness of at least 540, at least 570, or at least 590. The Vickers hardness can be between 540 and 800, between 570 and 700, or between 590 and 630.

[0095] The glass article can have an ion-exchanged layer, in particular a compressive stress layer, on one or both of its main surfaces. A compressive stress layer imparts high strength to the glass article. Optionally, the glass article can have a compressive stress of at least 500 MPa, at least 700 MPa, at least 900 MPa, at least 1100 MPa, or even at least 1200 MPa on one or both of its main surfaces. In some embodiments, the compressive stress can be up to 1800 MPa, up to 1600 MPa, up to 1500 MPa, or up to 1400 MPa. For example, the compressive stress can be between 500 MPa and 1800 MPa, between 700 MPa and 1600 MPa, or between 800 MPa and 1400 MPa. In one embodiment, the compressive stress is from 1200 to 1600 MPa, or from 1300 to 1500 MPa.

[0096] In one embodiment, the glass article has a thickness of 20 to 40 µm, e.g. 25 to 35 µm, and exhibits a compressive stress on one or both of its main surfaces of at least 800 MPa, at least 850 MPa, at least 900 MPa, or at least 900 MPa.

[0097] Optionally, the glass article has a depth of line (DoL) of 3 to 15 µm or 4 to 12 µm on one or both of its main surfaces. For example, the DoL can be at least 3 µm, at least 4 µm, at least 6 µm, at least 7 µm, or at least 8 µm. Alternatively or additionally, the DoL can be up to 15 µm, up to 13 µm, up to 12 µm, or up to 11 µm.

[0098] In one embodiment, the depth of lay (DoL) is between 10 and 25% of the article thickness or between 12 and 20% of the article thickness. In some embodiments, the DoL is at least 10%, at least 12%, or at least 14% of the article thickness. The DoL can be up to 33%, up to 25%, or up to 20% of the article thickness. In this context, the DoL refers to the depth of a compressive stress layer on a given surface. The total DoL of all compressive stress layers can be greater.

[0099] One of the remarkable properties of the glass article described in this disclosure is that very high compressive stresses can be achieved even in thin glass articles. In embodiments, the glass article has a compressive stress ratio in MPa to article thickness in µm of at least 4.0 MPa / µm, at least 5.0 MPa / µm, at least 6.0 MPa / µm, or at least 10.0 MPa / µm on one or both of its main surfaces. In embodiments, this value can be as high as 40.0 MPa / µm, up to 35.0 MPa / µm, or up to 30.0 MPa / µm. Optionally, the compressive stress ratio in MPa to article thickness in µm can be as high as 10.0 MPa / µm, up to 8.0 MPa / µm, or up to 7.0 MPa / µm. In certain embodiments, the ratio of compressive stress in MPa to article thickness in µm is in the range of 4.0 MPa / µm to 40.0 MPa / µm, 5.0 MPa / µm to 35.0 MPa / µm, 5.0 MPa / µm to 30.0 MPa / µm or 10.0 MPa / µm to 29.0 MPa / µm.In a particular embodiment, this value ranges from 20.0 MPa / µm to 30.0 MPa / µm. In another embodiment, the ratio of the compressive stress in MPa to the thickness of the article is at least 20.0 MPa / µm or at least 25.0 MPa / µm.

[0100] Optionally, the glass article can have a surface compressive stress ratio (in MPa) to the depth of the ion-exchanged layer (DoL) (in µm) of at least 50 MPa / µm, at least 75 MPa / µm, or at least 90 MPa / µm on one or both of its main surfaces. In one embodiment, this value is even at least 100 MPa / µm, at least 120 MPa / µm, or at least 140 MPa / µm. For example, the ratio of compressive stress (in MPa) to the depth of the ion-exchanged layer (in µm) can be between 50 and 400 MPa / µm, between 75 and 300 MPa / µm, or between 90 and 200 MPa / µm. In certain embodiments, the ratio of the compressive stress in MPa to the depth of the ion-exchanged layer in µm is up to 400 MPa / µm, up to 300 MPa / µm or up to 200 MPa / µm.

[0101] In one embodiment, the glass article exhibits excellent three-point flexural strength, showing a three-point flexural strength of at least 100 MPa, at least 200 MPa, or at least 300 MPa. It is noteworthy that such strength can be achieved even without ion exchange strengthening. With such high initial strength, the strength of the product after ion exchange is even more remarkable. Optionally, the three-point flexural strength can be in the range of 100 MPa to 600 MPa, 200 MPa to 500 MPa, or 300 MPa to 400 MPa. In one embodiment, this disclosure relates to a glass article exhibiting a three-point flexural strength of at least 400 MPa, at least 500 MPa, or at least 600 MPa. It is noteworthy that such strength can be achieved. Optionally, the three-point bending strength can be between 400 MPa and 1200 MPa, between 500 MPa and 1000 MPa or between 600 MPa and 800 MPa.

[0102] In one embodiment, the temperable glass article has a low-temperature tempering value LTT. 200µm of at least 1150 MPa, at least 1200 MPa, at least 1250 MPa, or at least 1300 MPa. Optionally, the low-temperature bias value is up to 1600 MPa, up to 1500 MPa, up to 1400 MPa, or up to 1375 MPa. The LTT 200µm In particular, it can range from 1150 MPa to 1600 MPa, from 1200 MPa to 1500 MPa or from 1250 MPa to 1400 MPa.

[0103] In one embodiment, the temperable glass article has a mid-temperature tempering value MTT. 200µm of at least 1100 MPa, at least 1200 MPa, at least 1225 MPa, or at least 1250 MPa. Optionally, the mean temperature bias value is up to 1500 MPa, up to 1400 MPa, up to 1350 MPa, or up to 1300 MPa. The MTT 200µm In particular, it can range from 1100 MPa to 1500 MPa, from 1200 MPa to 1400 MPa or from 1200 MPa to 1350 MPa.

[0104] In one embodiment, the temperable glass article has a low-temperature tempering value LTT. 30µm of at least 800 MPa, at least 850 MPa, at least 900 MPa, or at least 950 MPa. Optionally, the low-temperature preload value LTT is... 30µm Up to 1400 MPa, up to 1300 MPa, up to 1100 MPa, or up to 1000 MPa. The LTT 30µm In particular, it can range from 800 MPa to 1400 MPa, from 900 MPa to 1300 MPa or from 950 MPa to 1100 MPa.

[0105] In one embodiment, the temperable glass article has a mid-temperature tempering value MTT. 30µm of at least 700 MPa, at least 750 MPa, at least 800 MPa, or at least 900 MPa. Optionally, the mean temperature bias value (MTT) is... 30µm Up to 1300 MPa, up to 1200 MPa, up to 1100 MPa, or up to 950 MPa. The MTT 30µm In particular, it can range from 700 MPa to 1300 MPa, from 800 MPa to 1200 MPa or from 900 MPa to 1100 MPa.

[0106] In one embodiment, the temperable glass article exhibits a low-temperature diffusion capacity D LT of at least 4.0 µm 2 / h, at least 8.0 µm 2 / h, at least 10.0 µm 2 / h, at least 12.0 µm 2 / h or at least 14.0 µm 2 / h on. Optionally, D is LT at most 100 µm 2 / h, at most 80 µm 2 / h, at most 60 µm 2 / h, at most 40 µm 2 / h, at most 25 µm 2 / h or at most 20 µm 2 / h. In one embodiment, the D is LT of 4.0 µm 2 / h up to 100 µm 2 / h, from 8.0 µm 2 / h up to 60 µm 2 / h, from 10.0 µm 2 / h up to 40 µm 2 / h or from 14.0 µm 2 / h up to 25 µm 2 / h.

[0107] In one embodiment, the temperable glass article has a diffusion capacity D of at least 20.0 µm 2 / h, at least 25.0 µm 2 / h, at least 30.0 µm 2 / h or at least 40.0 µm 2 / h. Optionally, D is at most 300 µm. 2 / h, at most 200 µm 2 / h, at most 150 µm 2 / h, at most 100 µm 2 / h, at most 80 µm 2 / h or at most 70 µm 2 / h. In one embodiment, D is 20.0 µm 2 / h up to 300 µm 2 / h, from 25.0 µm 2 / h up to 200 µm 2 / h, from 25.0 µm 2 / h up to 100 µm 2 / h or from 30.0 µm 2 / h up to 80 µm 2 / h.

[0108] The glass article can, in particular, have a center tensile stress (CT) of more than 50 MPa, more than 100 MPa, more than 200 MPa, more than 500 MPa, or more than 1000 MPa. Optionally, this value is a maximum of 2000 MPa, a maximum of 1800 MPa, a maximum of 1600 MPa, or a maximum of 1400 MPa. In one embodiment, the CT value can be from 50 MPa to 2000 MPa, from 100 MPa to 1800 MPa, from 200 MPa to 1600 MPa, or from 1000 MPa to 1400 MPa.

[0109] In one embodiment, the glass article is bendable up to a bending radius of 25 mm without failure. In preferred embodiments, the glass article even has a bending radius of 20 mm, 15 mm, 10 mm, 8 mm, or 5 mm. Optionally, the glass article is foldable, in particular it has a bending radius of 4 mm, 3 mm, 2 mm, or 1 mm. Electronic device

[0110] The glass and / or glass article can be used in an electronic device, such as a portable computer, smartphone, tablet computer, or other portable devices. The glass and / or glass article can be part of a display. Thus, an electronic device according to this disclosure can include a glass or glass article as described herein. The electronic device can include a display, wherein the display comprises the glass and / or glass article of this disclosure. The glass article can be a cover glass of the electronic device.

[0111] The electronic device can be a flexible, bendable and / or foldable device, such as a flexible and / or foldable smartphone or tablet computer.

[0112] One embodiment relates to an electronic device with at least one display and a display cover, wherein the display cover comprises or consists of glass and / or a glass article as described in this disclosure. Methods for manufacturing

[0113] The glass can be produced by melting a mixture of raw materials suitable for achieving the properties described in this disclosure. The glass can, for example, be melted in a platinum crucible. After melting, the molten glass can be refined with one or more refining agents to remove bubbles. Instead of chemical refining agents, physical refining methods such as vacuum refining can also be used.

[0114] On an industrial scale, glass articles can be manufactured using down draw or overflow fusion processes. The down draw process is preferred because it allows for very thin products.

[0115] After shaping, the object can be hardened by ion exchange (also called "chemical hardening" or "chemical tempering"). The hardening process can involve immersing the object in a bath of molten salt. The salt is selected according to the desired ion exchange method. Preferably, the salt is potassium nitrate. In certain embodiments, the salt bath contains potassium nitrate, optionally about 100% KNO3.

[0116] The chemical tempering of a glass article by ion exchange is well known to those skilled in the art. The tempering process can be carried out by immersing the glass article in an ion exchange bath containing monovalent ions, which are exchanged for the alkali ions in the glass. The monovalent ions in the ion exchange bath have larger radii than the alkali ions in the glass, e.g., K + and / or Cs +Ion exchange creates compressive stress in the glass because the larger ions occupy more space within the glass structure. This significantly improves the glass's strength. Furthermore, the compressive stress induced by chemical strengthening enhances the bending properties of the tempered glass article and increases its scratch resistance. Typical salts used for chemical tempering include, for example, K + -containing molten salts or salt mixtures are used. Optional ion exchange baths for chemical prestressing are Na + - and / or K +-containing molten salts or mixtures thereof. Possible salts are NaNO3, KNO3, CsNO3, NaCl, KCl, CsCl, Na2SO4, K2SO4, Cs2SO4, Na2CO3, K2CO3, Cs2CO3, and K2Si2O5, as well as combinations thereof. Preferably, the ion exchange bath comprises KNO3. Additives such as NaOH, KOH, and other sodium or potassium salts can also be used to better control the rate of ion exchange for chemical strength enhancement. The ion exchange can take place at temperatures in the range of 300 °C to 500 °C or from 340 °C to 490 °C, particularly from 340 °C to 450 °C or from 360 °C to 450 °C. In one embodiment, the ion exchange temperature is less than 420 °C or less than 400 °C. Optionally, the temperature of the salt bath during ion exchange can be adjusted within a temperature range of T g -400 to T g -100 °C or from T g -260 to T g temperatures of -130 °C.

[0117] Chemical tempering is not limited to a single step. It can involve several steps in one or more salt baths containing alkali metal ions of varying concentrations and / or different ions in the salt baths to achieve improved tempering performance. Thus, chemically tempered glass can be tempered in one step or in several steps, such as two. Two-step chemical tempering is particularly common with Li₂O-containing glasses, as lithium can be exchanged for both sodium and potassium ions.

[0118] The inventors discovered that the glass exhibits very rapid ion exchange and achieves high compressive stress within a short time, even at very low tempering temperatures. The immersion time of the object in the ion exchange bath at the specified temperatures can range from 5 minutes to 12 hours, from 10 minutes to 4 hours, or from 20 minutes to 2 hours. Optionally, the time is at least 5 minutes, at least 10 minutes, or at least 20 minutes. In some embodiments, the ion exchange time is no more than 2 hours, no more than 1 hour, or no more than 30 minutes.

[0119] In one embodiment, the method for manufacturing a glass comprises the following steps: - Providing glass raw materials suitable for obtaining a glass according to this disclosure, - Melting the glass raw materials into a glass melt, - optionally shaping the molten glass into a glass article, in particular in a drawing process, especially in a down draw process or overflow fusion process, - Cooling of the molten glass or, optionally, the glass article.

[0120] In one embodiment, the method also includes the chemical tempering of the glass article, comprising the steps: - Placing the glass article in an ion exchange bath, - Exchanging ions of the glass article to be exchanged for ions of the ion exchange bath at an ion exchange temperature, wherein the ions of the ion exchange bath have at least partially a larger ion diameter than the ions of the glass article to be exchanged, wherein the ion exchange temperature is from 300 to 500 °C, preferably at most 420 °C. Pre-tensioning method

[0121] In one embodiment, this disclosure relates to a method for chemically tempering a glass article consisting of a glass according to this disclosure, comprising the steps: - Placing the glass article in an ion exchange bath, - Exchanging ions to be exchanged from the glass article for ions from the ion exchange bath at an ion exchange temperature, wherein the ions of the ion exchange bath have at least partially a larger ion diameter than the ions to be exchanged from the glass article.

[0122] The chemical tempering of a glass article by ion exchange is well known to those skilled in the art. The tempering process can be carried out by immersing the glass article in an ion exchange bath containing monovalent ions, which are exchanged for the alkali ions in the glass. The monovalent ions in the ion exchange bath have larger radii than the alkali ions in the glass, e.g., K + and / or Cs +Ion exchange creates compressive stress in the glass because the larger ions occupy more space within the glass structure. After ion exchange, the glass's strength is significantly improved. Furthermore, the compressive stress induced by chemical strengthening improves the bending properties of the tempered glass article and increases its scratch resistance. Typical salts used for chemical tempering include, for example, K + -containing molten salts or salt mixtures are used. Optional ion exchange baths for chemical prestressing are Na + - and / or K +-containing molten salts or mixtures thereof. Possible salts are NaNO3, KNO3, CsNO3, NaCl, KCl, CsCl, Na2SO4, K2SO4, Cs2SO4, Na2CO3, K2CO3, Cs2CO3, and K2Si2O5, as well as combinations thereof. Preferably, the ion exchange bath comprises KNO3. Additives such as NaOH, KOH, and other sodium or potassium salts can also be used to better control the rate of ion exchange for chemical strength enhancement. The ion exchange can take place at temperatures in the range of 300 °C to 500 °C or from 340 °C to 490 °C, particularly from 340 °C to 450 °C or from 360 °C to 450 °C. In one embodiment, the ion exchange temperature is less than 420 °C or less than 400 °C. Optionally, the temperature of the salt bath during ion exchange can be adjusted within a temperature range of T g -400 to T g -100 °C or from T g -260 to T g temperatures of -130 °C.

[0123] Chemical tempering is not limited to a single step. It can involve several steps in one or more salt baths containing alkali metal ions of varying concentrations and / or different ions in the salt baths to achieve improved tempering performance. Thus, chemically tempered glass can be tempered in one step or in several steps, such as two. Two-step chemical tempering is particularly common with Li₂O-containing glasses, as lithium can be exchanged for both sodium and potassium ions.

[0124] The inventors discovered that the glass exhibits very rapid ion exchange and achieves high compressive stress within a short time, even at very low tempering temperatures. The immersion time of the object in the ion exchange bath at the specified temperatures can range from 5 minutes to 12 hours, from 10 minutes to 4 hours, or from 20 minutes to 2 hours. Optionally, the time is at least 5 minutes, at least 10 minutes, or at least 20 minutes. In some embodiments, the ion exchange time is no more than 2 hours, no more than 1 hour, or no more than 30 minutes. Uses

[0125] This disclosure also relates to the use of the glass and glass articles described herein. Glass articles or glasses of this disclosure may, for example, be used as or in displays, display covers, laminates, or wafers. The displays, display covers, laminates, or wafers may be flexible or foldable. Exemplary embodiments

[0126] Below are some special embodiments of the products and processes of this disclosure which, alone or in combination with the features described above, are the subject of this disclosure.

[0127] In a first exemplary embodiment, this disclosure relates to a glass that is free of As2O3 and Sb2O3, comprising in mol%: from until SiO2 50,0 70,0 Al2O3 > 10,0 14,5 B2O3 0,0 5,0 Li2O 0,0 5,0 Na2O > 14,0 25,0 K2O 0,0 5,0 MgO 0,0 6,0 CaO 0,0 5,0 ZnO 0,0 5,0 ZrO2 0,0 3,0 where the stoichiometric ratio Na2O / Al2O3 is from 1.35 to 1.50 and where the stoichiometric ratio SiO2 / (Al2O3+ZrO2) is from 4.00 to 5.50.

[0128] In a second exemplary embodiment, this disclosure relates to a glass that is free of As2O3 and Sb2O3, comprising in mol%: from until SiO2 50,0 70,0 Al2O3 > 10,0 14,5 B2O3 0,0 5,0 Li2O 0,0 5,0 Na2O > 14,0 25,0 K2O 0,0 5,0 MgO 0,0 6,0 CaO 0,0 5,0 ZnO 0,0 5,0 ZrO2 0,0 3,0 wherein the stoichiometric ratio Na2O / Al2O3 is from 1.35 to 1.50 and wherein the stoichiometric ratio SiO2 / (Al2O3+ZrO2) is from 4.00 to 5.50, and wherein the glass has a low-temperature preload value LTT 200µm of at least 1150 MPa, a low-temperature bias value LTT 30µm of at least 800 MPa and a crystal growth rate of 10 5 dPa*s of less than 0.50 µm / min.

[0129] In a third exemplary embodiment, this disclosure relates to a glass comprising the components SiO2, Al2O3 and Na2O, and optionally ZrO2, wherein the molar ratio of Na2O / Al2O3 is from 1.35 to 1.75 and wherein the molar ratio of SiO2 / (Al2O3+ZrO2) is from 3.00 to 4.90, wherein the glass comprises (in mol%): from until SiO2 50,0 70,0 Al2O3 > 10,0 14,5 Na2O > 14,0 25,0 MgO 0,0 6,0 ZrO2 0,0 3,0 R2O >14,0 30,0 R'O 0,0 10,0

[0130] In a fourth exemplary embodiment, this disclosure relates to a glass comprising the components SiO2, Al2O3 and Na2O, and optionally ZrO2, wherein the molar ratio of Na2O / Al2O3 is from 1.35 to 1.75 and wherein the molar ratio of SiO2 / (Al2O3+ZrO2) is from 3.00 to 4.90, wherein the glass comprises (in mol%): from until SiO2 50,0 70,0 Al2O3 > 10,0 14,5 Na2O > 14,0 25,0 MgO 0,0 6,0 ZrO2 0,0 3,0 R2O >14,0 30,0 R'O 0,0 10,0 and wherein the glass has a low-temperature diffusion capacity D LT of at least 8.0 µm 2 / h and / or a crystal growth rate at 10 5 dPa*s of less than 0.50 µm / min.

[0131] In a fifth exemplary embodiment, this disclosure relates to a glass comprising the components SiO2, Al2O3 and Na2O, and optionally ZrO2, wherein the molar ratio of Na2O / Al2O3 is from 1.35 to 1.75 and wherein the molar ratio of SiO2 / (Al2O3+ZrO2) is from 3.00 to 4.90, wherein the glass comprises (in mol%): from until SiO2 50,0 70,0 Al2O3 > 10,0 14,5 Na2O > 14,0 25,0 MgO 0,0 6,0 ZrO2 0,0 3,0 R2O >14,0 30,0 R'O 0,0 10,0 and wherein the glass has a low-temperature diffusion capacity D LT of at least 12.0 µm 2 / h and / or a crystal growth rate at 10 5 dPa*s of less than 0.20 µm / min.

[0132] In a sixth exemplary embodiment, this disclosure relates to a glass comprising the components SiO2, Al2O3 and Na2O, and optionally ZrO2 and - a low-temperature preload value LTT 30µm of at least 8000 MPa, - a low-temperature diffusion capacity D LT of at least 8.0 µm 2 / h, - a crystal growth rate at 10 5 dPa*s of less than 0.50 µm / min, - a mid-temperature preload value MTT 200µm of at least 1100 MPa.

[0133] In a seventh exemplary embodiment, this disclosure relates to a glass comprising the components SiO2, Al2O3 and Na2O, and optionally ZrO2 and - a low-temperature preload value LTT 200µm of at least 11500 and at most 1500 MPa, - a low-temperature diffusion capacity D LT of at least 12.0 µm 2 / h and at most 20.0 µm 2 / h, - a crystal growth rate at 10 5 dPa*s of less than 0.20 µm / min, - a mid-temperature preload value MTT 30µm of at least 800 MPa and at most 1300 MPa.

[0134] In an eighth exemplary embodiment, this disclosure relates to a glass with - a low-temperature preload value LTT 200µm of at least 1150 MPa, - a low-temperature diffusion capacity D LT of at least 8.0 µm 2 / h, - a crystal growth rate at 10 5 dPa*s of less than 0.50 µm / min, - a mid-temperature preload value MTT 30µm of at least 800 MPa, and - comprising a composition in mol% from until SiO2 50,0 70,0 Al2O3 > 10,0 14,5 Na2O > 14,0 25,0 MgO 0,0 6,0 ZrO2 0,0 3,0 R2O >14,0 30,0 R'O 0,0 10,0

[0135] In a ninth exemplary embodiment, this disclosure relates to a glass comprising the components SiO2, Al2O3 and Na2O, and optionally ZrO2 and - a low-temperature preload value LTT 30µm of at least 800 and at most 1500 MPa, - a low-temperature diffusion capacity D LT of at least 12.0 µm 2 / h and at most 20.0 µm 2 / h, - a crystal growth rate at 10 5 dPa*s of less than 0.20 µm / min, - a mid-temperature preload value MTT 200µm of at least 1100 MPa and at most 1500 MPa, - comprising a composition in mol% from until SiO2 57,5 65,0 Al2O3 11,5 13,5 B2O3 0,0 1,5 Li2O 0,0 1,0 Na2O > 16,0 20,0 K2O 0,0 1,5 MgO 3,0 5,0 CaO 0,0 1,5 SrO 0,0 1,0 BaO 0,0 1,0 ZnO 0,0 1,0 ZrO2 0,5 2,0

[0136] A tenth exemplary embodiment of this disclosure relates to a glass article made of glass according to one of the first to ninth embodiments having a thickness of less than 100 µm, in particular having a thickness of 20 µm to 80 µm.

[0137] An eleventh exemplary embodiment of this disclosure relates to a glass article made of a glass according to one of the first to ninth embodiments, having a thickness of less than 100 µm, in particular having a thickness of 20 µm to 80 µm, which has a surface roughness R on one or both of its main surfaces. a has a maximum thickness of 3.0 nm and an area of ​​at least 10 cm² 2 has.

[0138] A twelfth exemplary embodiment of this disclosure relates to a glass article made of a glass according to one of the first to ninth embodiments having a thickness of less than 100 µm, in particular having a thickness of 20 µm to 80 µm, which has a surface roughness R on one or both of its main surfaces. a has a maximum thickness of 3.0 nm and an area of ​​at least 10 cm² 2 has and exhibits an ion-exchanged layer, in particular a compressive stress layer, on one or both of its main surfaces.

[0139] A thirteenth exemplary embodiment of this disclosure relates to a glass article made of a glass according to one of the first to ninth embodiments having a thickness of less than 100 µm, in particular having a thickness of 20 µm to 80 µm, which has a surface roughness R on one or both of its main surfaces. a has a maximum thickness of 3.0 nm and an area of ​​at least 10 cm² 2has and exhibits a compressive preload of at least 800 MPa on at least one surface.

[0140] In a fourteenth exemplary embodiment, this disclosure relates to an electronic device with at least one display and a display cover, wherein the display cover comprises or consists of glass according to one of the first to ninth embodiments or a glass article according to one of the tenth to thirteenth embodiments. Examples

[0141] Exemplary compositions of glasses within the meaning of this disclosure were produced by melting suitable glass raw materials. The following table provides an overview of the compositions and properties of some exemplary glasses. The glasses were additionally purified with a small amount of SnO2 (approx. 0.04 mol%). The values ​​in the tables are rounded to one decimal place. Due to rounding differences, the constituents do not always add up to exactly 100.0%.

[0142] Thin glass sheets were produced from the glasses of these compositions. The sheet thickness was 200 µm. Subsequently, the sheets were chemically hardened in a salt bath of 100% KNO3 at 440 °C for 30 minutes or at 390 °C for 45 minutes. Exemplary glass compositions A B C D E F composition SiO2 61,7 59,6 55,7 60,8 62,9 63,0 Al2O3 11,7 13,7 14,1 13,0 12,5 12,7 B2O3 3,9 Na2O 20,0 19,8 19,9 19,2 18,0 18,1 K2O 0,8 0,8 0,8 0,8 MgO 2,9 4,4 2,9 4,4 4,0 3,8 CaO 1,5 1,7 ZnO ZrO2 1,9 0,6 1,4 0,6 0,6 0,6 SnO2 F 0,5 0,5 0,5 0,6 Cl 0,3 0,5 0,4 0,6 0,6 0,5 sum 100,0 99,9 100,0 99,9 99,9 100,1 Na2O / Al2O3 1,71 1,45 1,41 1,48 1,44 1,43 SiO2 / (Al2O3+ZrO2) 4,54 4,17 3,59 4,47 4,80 4,74 Characteristics CTE [ppm / K] 9,47 9,99 9,39 10,01 9,60 9,52 T g [°C] 610 606 580 605 613 602 Density [g / cm³] 3 ] 2,528 2,492 2,513 2,491 2,479 2,476 E-module [GPal 75 74 74 74 73 OEG [°C] 991 1091 1094 1053 KWR [µm / min] 0 0,03 0,04 0,02 0 Liquid viscosity [dPa*s] 10 5,68 10 4.96 10 4,83 10 5,39 LTT 200µm [MPa] 1462 1416 1389 1399 1348 DOL LTT [µm] 7,0 9,9 5,0 9,6 9,6 D LT [µm 2 / h] 8,33 16,67 4,25 15,67 15,67 MTT 200µm [MPa] 1341 1340 1419 1298 1261 DoL MTT [µm] 11,6 16,4 8,9 15,6 15,5 D [µm 2 / h] 34,33 68,61 20,21 62,08 61,29 FDSS [MPa*min / µm] >100.000 47200 34725 69950 >100.000 Comparative compositions I II III IV V VI VII composition SiO2 57,1 57,5 56,2 54,8 62,4 67,9 65,4 Al2O3 17,7 16,8 16,4 16,4 11,2 10,5 11,3 B2O3 2,3 2,4 Na2O 18,6 18,9 19,5 19,5 19,5 14,9 16,5 K2O 0,8 1,3 0,9 MgO 2,3 2,9 3,0 3,0 4,3 3,8 4,3 CaO 1,3 1,6 1,6 1,7 ZnO 2,5 ZrO2 1,9 0,6 1,9 0,6 0,5 0,6 SnO2 F 0,5 0,5 0,5 Cl 0,5 0,3 0,3 0,3 0,5 0,4 0,5 sum 100,0 99,9 99,9 100,0 99,8 99,8 100,0 Na2O / Al2O3 1,05 1,13 1,19 1,19 1,74 1,41 1,46 SiO2 / (Al2O3+ZrO2) 3,23 3,08 3,31 2,99 5,30 6,12 5,48 Characteristics CTE [ppm / K] 9,05 8,94 9,34 9,17 9,94 8,90 T g [°C] 660 688 606 629 575 602 Density [g / cm³] 3 ] 2,530 2,536 2,495 2,529 2,483 2,455 E-modulus [GPa] 76 78 74 75 73 72 OEG [°C] 1228 >1492 1142 >1491 937 KWR [µm / min] >0,5* >0,5* >0,5* >0,5* 0,0 Liquid viscosity [dPa*s] 10 4,24 <10 2,71 10 4,45 <10 2,41 10 5,99 MTT 200µm [MPa] 1554 1573 1457 1552 1091 1016 1168 DoLMTT [µm] 12,7 12,3 10,7 10,1 16,0 17,0 14,7 D [µm 2 / h] 41,15 38,60 29,21 26,02 65,31 73,72 55,13 *These samples were completely crystallized with a KWR significantly above 0.5 µm / min (outside the measuring range).

[0143] The compositions of comparative examples I to IV show that the tendency to crystallize increases significantly when the ratio of Na₂O to Al₂O₃ is too low. Glasses with a crystal growth rate of 0.5 µm / min or more are unsuitable for production by drawing processes such as down draw or overflow fusion. Furthermore, it can be seen that the mid-temperature prestress values ​​(MTT) 30min / KNO3 The values ​​for comparison lenses I to IV are significantly higher than those for examples A to F. The thicknesses of the ion-exchanged layer DoL MTT are lower in the comparison examples.

[0144] The comparative examples V, VI, and VII show that while good resistance to crystallization can be achieved when the SiO2 / (Al2O3+ZrO2) ratio is exceeded, the mid-temperature prestress values ​​are very low. Results for low-temperature prestressing are also available for comparative examples V, VI, and VII. V VI VII LTT 200µm [MPa] 1230 1068 1219 DOL LTT [µm] 9,7 10,0 9,3 D LT [µm 2 / h] 16,00 17,01 14,71

[0145] This also shows that high prestresses are not achievable.

[0146] In a further experiment, a tank melt was performed with glass E, and the glass was drawn to a thickness of 32 µm. This glass was subjected to chemical prestressing with 100% KNO3. A compressive stress of over 950 MPa was achieved.

[0147] The synthesis of these experimental data reveals that the inventors have identified a compositional range for aluminosilicate glasses that combines a multitude of properties crucial for thin and ultra-thin display glass. These advantageous glasses can be prestressed to remarkably high CS values ​​while still exhibiting sufficient crystallization resistance for down-draw processing. A compressive prestress of over 900 MPa in a 32 µm thick glass article was previously unimaginable with industrially producible glass. It is particularly surprising that such impressive values ​​can be achieved in a glass system as extensively researched as that of aluminosilicates, and without the addition of difficult-to-handle, toxic, or particularly expensive components. Crystallization experiment

[0148] To gain a visual impression of the crystallization properties of the glasses, glass samples were held at different temperatures for 16 hours each. The samples were then visually examined for crystal formation.

[0149] The images show microphotographs of glass samples at approximately 100x magnification.

[0150] Fig. shows the result of a heat treatment of a glass sample of composition A at 1010 °C, which corresponds to a viscosity of 10 5,5 dPa*s corresponds to this. Due to a very low crystal growth rate, only very small crystals of about 1 µm in size are visible.

[0151] Fig. The result for example composition B after heat treatment at 1140 °C, corresponding to a viscosity of 10, is shown. 4,6 dPa*s corresponds. Fig. The result is shown at 1060 °C, corresponding to a viscosity of 10. 5,2dPa*s. No crystals are visible in the images.

[0152] Fig. shows a sample of composition E with a very low crystal growth rate at 1010 °C, corresponding to 10 5,8 dPa*s. Only very few and very small crystals formed (up to 4.7 µm).

[0153] Fig. shows a sample of the comparison composition III after heat treatment at 1060 °C, which corresponds to a viscosity of 10 5,14 dPa*s corresponds to the sample being completely crystallized, which corresponds to an estimated crystal growth rate of >0.5 µm / min. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited non-patent literature

[0000] DIN ISO 7991:1987

[0023]

Claims

[1] Glass free of As2O3 and Sb2O3, comprising in mol% from until SiO2 50,0 70,0 Al2O3 > 10,0 14,5 B2O3 0,0 5,0 Li2O 0,0 5,0 Na2O > 14,0 25,0 K2O 0,0 5,0 MgO 0,0 6,0 CaO 0,0 5,0 ZnO 0,0 5,0 ZrO2 0,0 3,0 where the molar ratio Na2O / Al2O3 is from 1.35 to 1.75 and where the molar ratio SiO2 / (Al2O3+ZrO2) is from 3.00 to 4.

90. [2] Glass according to claim 1 having a fluorine content of more than 0.2 mol%. [3] Glass according to claim 1 or 2 having a K2O content of more than 0.3 mol%. [4] Glass according to at least one of the preceding claims comprising in mol% from until SiO2 55,0 65,0 Al2O3 11,5 14,5 B2O3 0,0 3,0 Li2O 0,0 1,0 Na2O > 16,0 22,0 K2O 0,0 3,0 MgO 1,0 5,0 CaO 0,0 3,0 ZnO 0,0 3,0 ZrO2 0,0 2,0 [5] Glass according to at least one of the preceding claims having a low-temperature diffusivity D LT of at least 4.0 µm 2 / h, at least 8.0 µm 2 / h, at least 10.0 µm 2 / h, at least 12.0 µm 2 / h or at least 14.0 µm 2 / h. [6] Glass according to at least one of the preceding claims with a low-temperature tempering value LTT 200µmof at least 1150 MPa, at least 1200 MPa, at least 1250 MPa or at least 1300 MPa. [7] Glass according to at least one of the preceding claims with a low-temperature tempering value LTT 30µm of at least 800 MPa, at least 850 MPa, at least 900 MPa or at least 950 MPa. [8] Glass according to at least one of the preceding claims having a crystal growth rate of 10 5 dPa*s of less than 0.50 µm / min, less than 0.20 µm / min, less than 0.10 µm / min, less than 0.05 µm / min or less than 0.02 µm / min. [9] Glass according to at least one of the preceding claims which is free from B2O3, P2O5 and / or Li2O. [10] Glass according to at least one of the preceding claims having the following composition in mol%: from until SiO2 57,5 65,0 Al2O3 11,5 13,5 B2O3 0,0 1,5 Li2O 0,0 1,0 Na2O > 16,0 20,0 K2O 0,0 1,5 MgO 3,0 5,0 CaO 0,0 1,5 SrO 0,0 1,0 BaO 0,0 1,0 ZnO 0,0 1,0 ZrO2 0,3 2,0 [11] Glass according to at least one of the preceding claims having the following composition in mol%: from until SiO2 60,0 64,0 Al2O3 12,0 13,5 Na2O 17,0 19,0 K2O 0,3 1,5 MgO 3,0 5,0 CaO 0,0 1,5 SrO 0,0 1,0 BaO 0,0 1,0 ZnO 0,0 1,0 ZrO2 0,3 1,7 [12] Glass article comprising a glass according to one of the preceding claims or consisting thereof, wherein the glass article has at least in sections a thickness of less than 300 µm, in particular of less than 100 µm. [13] Glass article according to claim 12 with a compressive prestress on at least one surface of at least 500 MPa, in particular at least 800 MPa, and / or with a center tension of more than 50 MPa, more than 100 MPa, more than 200 MPa, more than 500 MPa or more than 1000 MPa. [14] An electronic device comprising at least one display and a display cover, wherein the display cover comprises or consists of a glass according to any one of claims 1 to 11 or a glass article according to any one of claims 12 to 13. [15] A process for producing a glass or glass article comprising the steps of: - Providing glass raw materials suitable for obtaining a glass according to one of claims 1 to 11, - Melting the glass raw materials to a glass melt, - optionally forming the molten glass into a glass article, - Cooling the molten glass or optionally the glass article. [16] Method according to claim 15, comprising the further step - chemical hardening of the glass or glass article by ion exchange.

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