Glass and glass article having high chemical temperability coupled with low tendency to crystallization and production process

Abstract

This disclosure relates to glass, glass articles and uses thereof, to processes for producing glass and glass articles, to methods of chemical tempering of a glass article, and to products comprising or consisting of glass or glass articles of the type described herein. The glasses are notable for very good chemical temperability coupled with low tendency to crystallization.

Description

[0001] Glass and glass articles with high chemical toughening capacity and low susceptibility to crystallization as well as manufacturing processes

[0002] This disclosure relates to glass, glass articles and uses thereof, methods for making glass and glass articles, methods for chemically toughening a glass article, and products containing or consisting of glass or glass articles of the type described herein.

[0003] Glass for display covers, such as those used in smartphones or tablet computers, must meet a number of requirements. For example, they must exhibit good mechanical stability and be economically viable to manufacture. For mechanical stability, it is important that the glass can be easily chemically tempered. During chemical tempering, smaller ions on the surface and down to a certain depth of a glass article are replaced by larger ones. This creates a compressive prestress on the surface, which improves mechanical stability, such as fracture toughness, edge strength, and puncture resistance.

[0004] The requirements for glasses intended for use in bendable and foldable displays are particularly high. These glasses must be able to be tempered to high compressive stress values, even at very thin thicknesses. At the same time, they should be amenable to processing using a drawing process such as down draw or overflow fusion (also known as "slot down draw" or "overflow down draw") for cost-effective production. Suitable viscosity profiles and crystallization resistance are required for these processing properties.

[0005] There is a need for glass compositions, articles and processes that generate particularly high compressive stresses even with low glass thicknesses and enable the most economical production possible.

[0006] Summary of Revelation

[0007] In a first aspect, this disclosure relates to a glass free of AS2O3 and Sb20a, comprising in mol%: where the molar ratio IX^O / AhCh is from 1.35 to 1.75 and the molar ratio SiCh / AhOs+ZrCh) is from 3.00 to 4.90.

[0008] In a second aspect, this disclosure relates to a glass comprising the components SiO2, Al2O3 and Na2O and optionally ZrO2, wherein the molar ratio Na2O / Al2O3 is from 1.35 to 1.75 and / or wherein the molar ratio SiO2 / (Al2O3+ZrO2) is from 3.00 to 4.90.

[0009] In a third aspect, this disclosure relates to a glass having a low temperature tempering value LTT2oo M mOf at least 1150 MPa, a low temperature tempering value LTT3o M m of at least 800 MPa and / or a crystal growth rate of 10 5 dPa*s of less than 0.50 pm / min.

[0010] In a fourth aspect, this disclosure relates to a glass having a low-temperature diffusivity DLT of at least 4.0 pm 2 / h and / or a crystal growth rate of 10 5 dPa*s of less than 0.50 pm / min.

[0011] In a fifth aspect, this disclosure relates to a glass article made from the glass according to any one of the first four aspects, in particular a glass article having a thickness of less than 300 pm and / or a compressive prestress on at least one surface of at least 800 MPa.

[0012] 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 a glass or a glass article according to any one of the first five aspects.

[0013] In a seventh aspect, this disclosure relates to a method for producing a glass comprising the steps:

[0014] Providing glass raw materials suitable for obtaining a glass according to one of the first four aspects,

[0015] Melting the glass raw materials to a glass melt, optionally forming the glass melt into a glass article,

[0016] Cooling the glass melt or, optionally, the glass article. 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:

[0017] Placing the glass article in an ion exchange bath,

[0018] Exchanging ions of the glass article to be exchanged with ions of the ion exchange bath at an ion exchange temperature, wherein the ions of the ion exchange bath at least partially have a larger ion diameter than the ions of the glass article to be exchanged, wherein the ion exchange temperature is 300°C to 500°C.

[0019] Short description of the figures

[0020] Figures 1 to 3 show photomicrographs of glass samples according to embodiments of this disclosure at 100x magnification after heat treatment.

[0021] Fig. 4 shows a microphotograph of a glass sample according to a comparative example at 100-fold magnification after heat treatment.

[0022] Detailed description

[0023] Definitions

[0024] "T4" is the temperature at which the glass has a viscosity of 10 4 dPa*s. 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. "T13" is the temperature at which the glass has a viscosity of 10 13 dPa*s. Similarly, other T n The temperatures indicated refer to the temperature at which the glass has a viscosity of 10 n dPa*s. "Ts" is, for example, the temperature at which the glass has a viscosity of 10 5dPa*s. The strain point (Ti4,s) is defined as a temperature at which all movements of the glass molecules have reached a point where no more strain can be introduced into the hot glass. It is a viscosity fixed point (temperature value) at the viscosity q = IO 145 dPa*s. This limit value usually represents the highest service temperature of a glass component. "T g " is the transformation temperature according to ISO 7884-8:1987.

[0025] To calculate the temperature required to achieve a given viscosity of a glass, the Vogel-Fulcher-Tammann (VFT) equation is usually used (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):

[0026] In the VFT equation, q is the viscosity, A and B are material parameters, T is the temperature, and To is the Vogel temperature. A, B, and To are constant for a given glass. Specifying these constants provides more precise information about the viscosity behavior of a specific glass composition.

[0027] The three-point bending strength is a test of a material's flexural 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; support width 16 mm; specimens measuring 28 x 28 x 0.2 mm. 3 ; prepared according to standard method 7.2.4; loading rate 5 mm / min.

[0028] 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 pm / min; loading rate 2 N / min; holding time 20 s; unloading rate 6 N / min.

[0029] The principal surfaces of a glass article are the two surfaces with the largest areas of all the surfaces of the glass article.

[0030] When this disclosure states that the glass is "free of" a component or that it does not contain a particular component, this means that this component may only be present in the glass as an impurity. This means that it is not added in significant amounts. Non-significant amounts are considered to be amounts of 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).

[0031] The liquidus temperature is the temperature above which no crystals form in a glass melt of a given composition, meaning 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 as a synonym for the liquidus temperature in this disclosure.

[0032] The glasses in this description are preferably produced by the drawing process. "Producible by the drawing process" refers in particular to production processes for thin glass (< 2.0 mm) and ultra-thin glasses (< 200 μm) such as down draw, e.g., with glass thicknesses of 75 μm and less. This means that the glass has the properties necessary for processing by the drawing process, in particular a crystal growth rate in the viscosity range important for the production process, which is viscosity 10 5 dPa*s. The crystal growth rate at 10 5In particular, dPa*s should be less than 0.50 pm / min so that the glass can be processed into thin glass and ultra-thin glass using the down draw process.

[0033] Crystal growth rate (KWR in pm / min) is a measure of the devitrification resistance of a glass. It is measured at a viscosity of 10 5dPa*s. The lower the crystal growth rate, the higher the devitrification resistance and the less waste can be produced. The manufacturing process can thus be stabilized and carried out continuously. The measurement of the crystal growth rate is well known. The crystal growth rate is determined by thermally treating the glass to be examined in the form of individual glass grains with a diameter of 2 mm to 3 mm on a platinum support for 16 hours in a gradient furnace with an increasing temperature regime. The crystal growth rate is microscopically observed and measured along the formed crystals, i.e., at their greatest extent. If, at a viscosity of 10 5 dPa*s no devitrification takes place at all, a crystal growth rate of 10 5dPa*s cannot be determined, which is stated here as 0 pm / min. The duration of 16 hours takes into account the fact that the residence time of the glass melt in the drawing process at this temperature can be of this order of magnitude.

[0034] The "thermal expansion coefficient" or "GTE" is the mean linear thermal expansion coefficient over a temperature range of 20 °C to 300 °C. It is determined according to DIN ISO 7991:1987.

[0035] In this description, "temperable" or "chemically toughenable" means that the material or article so designated can be chemically toughened. To do so, it must possess exchangeable ions that can be replaced by ions with larger radii. Examples of exchangeable ions include sodium ions. Glasses that do not contain alkali metal ions are considered non-temperable within the scope of this disclosure. A material or article that is temperable is not (yet) tempered, but can be subjected to such a process.

[0036] Compressive stress (CS) is the compression induced, for example, by chemical prestressing in the glass network at the surface of a glass article. Compressive stress typically decreases with increasing distance from the prestressed surface toward the bulk material. It is common practice, and is also used here, that the specification of a compressive stress refers to the maximum value at the described surface. Commercially available measuring instruments can be used to measure compressive stress, e.g., an FSM6000LE or an SLP1000 (both from Orihara Industrial Co. Ltd., Tokyo, JP).

[0037] The depth of the ion-exchanged layer, measured from the surface of a glass article into the volume of the article, is referred to in this disclosure as DoL ("depth of layer"). It is typically expressed in micrometers. This unit is familiar to those skilled in the art. It can be determined using commercially available measuring instruments, e.g., an FSM6000 (Luceo Co., Ltd., Tokyo, JP).

[0038] The diffusivity (D in pm) 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 pm) after ion exchange after a certain ion exchange time (IET in hours). The higher the diffusivity, the deeper the DoL after a certain time of ion exchange. exchange. The corresponding formula is D = — . Unless otherwise stated, the term D in this description refers to chemical tempering with potassium nitrate (100%) for 30 minutes. For very thin glass thicknesses (particularly below 100 μm), the duration of chemical tempering can be shortened, e.g., to 10 minutes. The temperature for this measurement is 440 °C. Unless otherwise stated, the diffusivity refers to a sample with a thickness of 200 μm.

[0039] In addition to the diffusivity, this description also includes the low temperature diffusivity (“low temperature diffusivity”, D L T in pm 2 / h). It is a measure of the ability of a toughenable glass to assume compressive prestress 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 ÜLT is determined in the same way as the previously described diffusivity, but at a lower temperature (390 °C) and for a slightly longer duration. The duration is 45 minutes; however, for very thin glass (particularly below 100 μm), the duration of chemical tempering can be shortened, e.g., to 20 minutes. Unless otherwise stated herein, the diffusivity refers to a sample with a thickness of 200 μm.

[0040] The low temperature toughening value 200 pm (low temperature toughening) LTT2oo Mm denotes the magnitude of the compressive stress CS in megapascals that can be achieved for a toughenable glass or glass article within a low-temperature toughening protocol for a glass thickness of 200 μm. A glass or glass article with a high low-temperature toughening value can therefore be chemically toughened at low temperatures. The low-temperature toughening protocol corresponds to the process described above for the low-temperature diffusivity DLT, namely 100% KNO3, 390 °C, 45 minutes. Accordingly, the middle-temperature toughening value at 200 μm (middle-temperature toughening) is MTT200. M m is the magnitude of the compressive stress CS in megapascals that can be achieved for a toughenable glass or glass article for a glass thickness of 200 pm under a toughening protocol as described above for diffusivity.

[0041] The low temperature toughening value 30 pm (low temperature toughening) LTT3o M m denotes the magnitude of the compressive stress CS in megapascals that can be achieved for a toughenable glass or a toughenable glass article for a glass thickness of 30 μm using a low-temperature toughening protocol. A glass or a glass article with a high low-temperature toughening value can therefore be chemically toughened well at low temperatures. The low-temperature toughening protocol corresponds to the process described above for low-temperature diffusivity DLT, namely 100% KNO3, 390 °C, 20 minutes. Accordingly, the mid-temperature toughening value 30 μm (middle temperature toughening) MTTsopm is the magnitude of the compressive stress CS in megapascals that can be achieved for a toughenable glass or a toughenable glass article for a glass thickness of 200 μm using a toughening protocol as described above for diffusivity.

[0042] This description uses a key value, the "flexible display suitability score" (FDSS), to assess the suitability of a glass for the economical production of glass articles for flexible displays. This value is calculated from the LTT2oo M m and the KWR as follows:

[0043] LTT200Mm = FDSS KWR

[0044] A glass is particularly suitable for the economical production of glass articles for flexible displays if the 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. The unit MPa*min / pm is omitted from the FDSS value for clarity.

[0045] Central tension (CT): When CS is induced on one or both sides of a glass article, according to the third principle of Newton's law, a tensile stress must be induced in the center of the glass to balance the stress. This stress is called "central tension." CT can be calculated from the measured CS and DoL values ​​using the following formula (t is the glass thickness).

[0046] The term "roughness" used here refers to the average roughness R a , which is a measure of the condition of a surface. Typically, amplitude parameters characterize the surface based on the vertical deviations of the roughness profile from the centerline. R a is the arithmetic mean of the absolute values ​​of these vertical deviations. This value can be determined according to DIN EN ISO 4287:2010-07.

[0047] For the purposes of this description, “cooling” includes, unless otherwise stated, both active cooling, for example using a cooling fluid (e.g. air or water), and passive cooling.

[0048] The glass described herein has particular advantages when used in glass articles of very thin thickness. Glass articles according to this disclosure may have such a thin thickness that they are bendable or even foldable. A "bendable" glass article is considered to be one that can be bent to a bending radius of 25 mm without failure. "Foldable" according to this description is a glass article that can be bent to a bending radius of 5 mm without failure. Some glass articles of this disclosure can be bent to bending radii significantly less than 5 mm.

[0049] A statement that a glass article "can be bent to a bending radius of X mm without failure" 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 specified, the test is conducted at a temperature of 25°C and a relative humidity of 30%.

[0050] Glass

[0051] The glass of this disclosure can be referred to as aluminosilicate glass or aluminosilicate glass, i.e., it contains silicon oxide and aluminum oxide as components. To enable chemical strengthening (synonym: "chemical toughening"), the glass also contains an interchangeable component, in this case the sodium ion in the sodium oxide. Furthermore, the glass can comprise other components to achieve or enhance specific properties. From the inventors' point of view, it is particularly surprising that, in the composition range discussed here, glasses can be produced that can be toughened to such high toughening values. In principle, the achievable toughening of a glass article also decreases with its decreasing thickness. In other words, a thin glass article can only be toughened to lower compressive stress values ​​by chemical toughening than a thicker article.For example, it is relatively easy to temper a conventional aluminosilicate display glass to tempering values ​​of over 1000 MPa if the glass article is over 300 μm thick. This is more difficult for very thin glasses, such as foldable glasses with thicknesses of, for example, 25 μm to 75 μm. While there are known measures that can be used to increase the temperability of glasses, such as by increasing the Al2O3 and ZrO2 contents, these measures increase the tendency of the glass to crystallize, especially in the viscosity range of approximately 10, which is important for forming in the down-draw process. 5 dPa*s. Development efforts in the glass industry are enormous to meet the electronics industry's demand for highly durable and bendable, or even foldable, glass products.

[0052] Optionally, the glass consists essentially of the components described herein, ie, it may be free of further components not discussed herein.

[0053] Preferably, the glass comprises the components SiO2, Al2O3 and Na2O and optionally ZrO2, wherein the molar ratio Na2O / AhO3 is from 1.35 to 1.75 and / or the molar ratio SiO2 / (AhO3+ZrO2) is from 3.00 to 4.90.

[0054] In one embodiment, the molar ratio Na2O / AhO3 is at least 1.10, at least 1.20, at least 1.30, at least 1.35, or at least 1.36. In a further embodiment, the molar ratio Na2O / AhO3 is at least 1.37, at least 1.38, at least 1.39, or at least 1.40. The molar ratio Na2O / AhO3 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 molar ratio Na2O / AI2O3 can be from 1.10 to 1.75, from 1.20 to 1.73, from 1.30 to 1.65, from 1.35 to 1.60, from 1.39 to 1.55, or from 1.40 to 1.50. In one embodiment, this ratio is from 1.36 to 1.75, from 1.37 to 1.73, from 1.38 to 1.65, or from 1.39 to 1.60.

[0055] In one embodiment, the molar 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 molar ratio SiO2 / (Al2O3+ZrO2) is at least 4.00, at least 4.40, or at least 4.50. The molar 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 molar ratio SiO2 / (AhO3+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.

[0056] According to this disclosure, the glass comprises SiO 2 , in particular in a content of at least 50.0 mol% and / or at most 70.0 mol%. In one embodiment, the SiO 2 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 SiO 2 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 one embodiment, the content of SiO2 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%.

[0057] According to this disclosure, the glass comprises Al2O3, in particular in a content of at least >10.0 mol% and / or at most 14.5 mol%. In one embodiment, the content of Al2O3 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 content of AlOs 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 content of AlOs 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 content of AhOs is from >10.0 mol% to 18.0 mol%, from 10.5 mol% to 17.0 mol%, from 11.0 mol% to 16.0 mol%, from 11.5 mol% to 14.5 mol%, or from 12.0 mol% to 14.0 mol%. Optionally, the AhOs content can be from 11.5 mol% to 14.5 mol%, from 12.0 mol% to 13.5 mol%, or from 12.0 mol% to 13.0 mol%. In one embodiment, the content of Al2O3 is more than 14.0 mol%.

[0058] According to this disclosure, the glass may comprise B2O3, in particular in a content of up to 5.0 mol%. In one embodiment, the content of B2O3 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 content of B2O3 in the glass may be up to 3.0 mol%, up to 2.0 mol%, or up to 1.5 mol%. In one embodiment, the content of B2O3 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 can be from 0.0 mol% to 1.5 mol% or the glass can be free of B2O3.

[0059] According to this disclosure, the glass may comprise Li2O, in particular in a content of up to 5.0 mol%, up to 2.5 mol%, or up to 1.0 mol%. Optionally, the U2O 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 U2O.

[0060] According to this disclosure, the glass comprises Na2O, in particular in a content 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 content of Na2O 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%.

[0061] According to this disclosure, the glass may comprise K2O, in particular in a content of up to 5.0 mol%. In one embodiment, the content of K2O 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 content of K2O 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 one embodiment, the content of K2O 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 can be from 0.0 mol% to 1.5 mol% or the glass can be free of K2O.

[0062] The molar ratio of the components K2O / Na2Ü can in particular be 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 molar ratio of the components K2O / Na2Ü is from 0.01 to 0.20, from 0.02 to 0.12, or from 0.03 to 0.08.

[0063] According to this disclosure, the glass may comprise MgO, in particular in a content 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 one 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%.

[0064] 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.

[0065] According to this disclosure, the glass may comprise CaO, in particular in a content 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 one 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.

[0066] According to this disclosure, the glass may comprise 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.

[0067] According to this disclosure, the glass may comprise 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.

[0068] The sum of the contents of the alkaline earth metal oxides 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%.

[0069] The molar ratio of the MgO / R'O components can in particular be 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 molar ratio of the MgO / R'O components is from 0.40 to 1.00, from 0.50 to 1.00, or from 0.90 to 1.00.

[0070] In one embodiment, the sum of the components AI2O3 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 one embodiment, the sum of the components AI2O3 and R'O is in a range from 14.0 mol% to 20.0 mol%, from 14.0 mol% to <18.0 mol%, or from 15.0 mol% to 17.5 mol%.

[0071] The sum of the alkali metal oxide contents in the glass is abbreviated as "RO." The alkali metal oxides are, in particular, UO, NaOO, KO, and CSOO. RO is preferably at least >14.0 mol%, at least 15.0 mol%, at least 16.0 mol%, or at least 17.0 mol%. Optionally, this sum is 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, RO is from 14.0 mol% to 30.0 mol%, from 16.0 mol% to 24.0 mol%, or from 17.0 mol% to 20.0 mol%.

[0072] The molar ratio of the MgO / R2O components can in particular be 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 molar ratio of the MgO / R2O components is from 0.10 to 0.30, from 0.12 to 0.25, or from 0.14 to 0.22.

[0073] According to this disclosure, the glass may comprise ZnO, in particular in a content 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 one 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.

[0074] According to this disclosure, the glass may comprise ZrO2, in particular in a content of at least 0.0 mol% and / or at most 3.0 mol%. In one embodiment, the content of ZrO2 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 content of ZrO2 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 one embodiment, the content of ZrO2 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%.

[0075] 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 one embodiment, the sum of the components Al2O3 and ZrO2 is in a range from 11.0 mol% to 17.0 mol%, from 12.0 mol% to 16.0 mol%, or from 12.5 mol% to 15.0 mol%.

[0076] The molar ratio of the components ZrO2 / Al2O3 can in particular be 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 molar ratio of the components ZrCh / AhCh is from 0.01 to 0.17, from 0.03 to 0.11, or from 0.03 to 0.08.

[0077] The molar ratio of the components ZrO2 / R'O can in particular be 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 molar 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.

[0078] According to this disclosure, the glass may comprise F, in particular in a content of up to 1.0 mol%. In one embodiment, the F content in the glass is at least 0.1 mol%, at least 0.3 mol%, or at least 0.4 mol%. Optionally, the F 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 one embodiment, the F 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 0.3 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 a molar amount of F (not F2).

[0079] According to this disclosure, the glass may comprise CI, in particular in a content of up to 1.0 mol%. In one embodiment, the content of CI in the glass is at least 0.1 mol%, at least 0.2 mol%, or at least 0.3 mol%. Optionally, the content of CI 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 one embodiment, the content of CI 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.

[0080] 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.

[0081] The glass composition may comprise one or more refining agents to remove bubbles from the melt during production. However, the two components AS2O3 and Sb2O3, which are of concern due to their toxicity, 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%, a maximum of 0.3 mol%, a maximum of 0.2 mol%, or a maximum of 0.1 mol%.

[0082] In one embodiment, the glass may contain color-imparting ions such as iron, cobalt, chromium, copper, vanadium, nickel, manganese, neodymium, erbium, europium, or molybdenum, or combinations thereof. They may be used in their various oxidation states. Optionally, the glass may contain one or more color components, in particular Fe2O3, CoO, and / or C^Os.

[0083] In one embodiment, the glass comprises in mol%:

[0084] In one embodiment, the glass comprises in mol%:

[0085] In one embodiment, the glass comprises in mol%:

[0086] In one embodiment, the glass comprises in mol%: The glass is optionally free of B2O3, P2O5 and / or U2O.

[0087] In one embodiment, the glass has a low temperature tempering value LTT2oo MmOf at least 1150 MPa, at least 1200 MPa, at least 1250 MPa, or at least 1300 MPa. Optionally, the low-temperature prestress value is up to 1600 MPa, up to 1500 MPa, up to 1400 MPa, or up to 1375 MPa. The LTkoopm can, in particular, be from 1150 MPa to 1600 MPa, from 1200 MPa to 1500 MPa, or from 1250 MPa to 1400 MPa.

[0088] In one embodiment, the glass has a mean temperature tempering value MTT2oo M m Of at least 1100 MPa, at least 1200 MPa, at least 1225 MPa or at least 1250 MPa. Optionally, the mid-temperature prestress value is up to 1500 MPa, up to 1400 MPa, up to 1350 MPa or up to 1300 MPa. The MTT2oopm can in particular be from 1100 MPa to 1500 MPa, from 1200 MPa to 1400 MPa or from 1200 MPa to 1350 MPa.

[0089] In one embodiment, the glass has a low-temperature tempering value LTTsopm of at least 800 MPa, at least 850 MPa, at least 900 MPa, or at least 950 MPa. Optionally, the low-temperature tempering value LTTao m is up to 1400 MPa, up to 1300 MPa, up to 1100 MPa, or up to 1000 MPa. In particular, the LTTao m can be from 800 MPa to 1400 MPa, from 900 MPa to 1300 MPa, or from 950 MPa to 1100 MPa.

[0090] In one embodiment, the glass has a mean temperature tempering value MTTsopm of at least 700 MPa, at least 750 MPa, at least 800 MPa, or at least 900 MPa. Optionally, the mean temperature tempering value MTTsopm is up to 1300 MPa, up to 1200 MPa, up to 1100 MPa, or up to 950 MPa. In particular, the MTTsopm can be from 700 MPa to 1300 MPa, from 800 MPa to 1200 MPa, or from 900 MPa to 1100 MPa.

[0091] In one embodiment, the glass has a crystal growth rate of 10 5dPa*s of less than 0.50 pm / min, less than 0.20 pm / min, less than 0.10 pm / min, less than 0.05 pm / min or less than 0.02 pm / min.

[0092] In one embodiment, the glass has a low-temperature diffusivity D L T of at least 4.0 pm 2 / h, at least 8.0 pm 2 / h, at least 10.0 pm 2 / h, at least 12.0 pm 2 / h or at least 14.0 pm 2 / h. Optionally, DLT is a maximum of 100 pm 2 / h, maximum 80 pm 2 / h, maximum 60 pm 2 / h s maximum 40 pm 2 / h, maximum 25 pm 2 / h or at most 8 pm 2 / h. In one embodiment, the DLT of 4.0 pm 2 / h until 100 pm 2 / h, from 8.0 pm 2 / h until 60 pm 2 / h, from 10.0 pm 2 / h until 40 pm 2 / h or from 14.0 pm 2 / h until 25 pm 2 / h.

[0093] In one embodiment, the glass has a diffusivity D of at least 20.0 pm 2 / h, at least 25.0 pm 2 / h, at least 30.0 pm 2 / h or at least 40.0 pm 2 / h. Optionally, D is a maximum of 300 pm 2 / h, maximum 200 pm 2 / h, maximum 150 pm 2 / h s maximum 100 pm 2 / h, maximum 80 pm 2 / h or at most 70 pm 2 / h. In one embodiment, D is 20.0 pm 2 / h until 300 pm 2 / h, from 25.0 pm 2 / h until 800 pm 2 / h, from 25.0 pm 2 / h until 100 pm 2 / h or from 30.0 pm 2 / h until 80 pm 2 / h.

[0094] The glass may 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 may 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 may have a modulus of elasticity (in GPa) between 73 and 75. Too high a modulus of elasticity may reduce the bendability of a glass article made from the glass.

[0095] In one embodiment, the average thermal expansion coefficient GTE may be at least 8.50, at least 8.75, at least 9.0, at least 9.25, or at least 9.5.

[0096] The glass preferably exhibits good suitability for the economical 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.

[0097] Glass items

[0098] A glass article within the meaning of this disclosure may have a thickness of 1,000 μm or less and be made of a glass as described herein. In general, 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. In order for the glass article to be sufficiently impact-resistant, a minimum thickness may be required. The minimum thickness may be at least 5 μm, at least 10 μm, at least 15 μm, or at least 20 μm.

[0099] In particular, the glass article may have a thickness of 1,000 μm or less, at least in sections, and be made of a glass as described here. 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 sections. In some embodiments, the thickness may be 80 μm or less, or 70 μm or less, at least in sections. Some articles have a thickness of 50 μm or less, or 40 μm or less, at least in 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 sections. In order for the glass article to be sufficiently impact-resistant, a minimum thickness may be required. The minimum thickness may be at least in sections at least 5 μm, at least 10 μm, at least 15 μm, or at least 20 μm.In this context, “at least in sections” means that the glass article has portions with the specified thickness. For example, the glass article can be bendable or foldable and, for this purpose, have a bending region where the bending takes place. This bending region can be thinner than other sections of the glass article. In this way, the advantages of particularly thin glass sections (bendability) and somewhat thicker glass sections (mechanical stability) can be combined. In one embodiment, the glass article has a bending region in which the glass article has a thickness that is less than 100 pm, less than 80 pm, less than 60 pm, or less than 40 pm. In one embodiment, the thickness in the bending region is at least 10 pm or at least 20 pm. Outside the bending region, the glass article can have a thickness of more than 100 pm, in particular at least 150 pm or at least 200 pm.In one embodiment, the thickness of the glass article outside the bending range is at least twice or at least three times the smallest thickness within the bending range.

[0100] The glass article can cover an area of ​​at least 10 cm 2 , at least 15 cm 2 or at least 20 cm 2 In embodiments, the article may have an area of ​​less than 10,000 cm 2 , less than 1,000 cm 2 or less than 200 cm 2 have.

[0101] The glass article may have a surface roughness R on one or both of its main surfaces aof a maximum of 5.0 nm, a maximum of 3.0 nm, or a maximum of 1.5 nm. This very low roughness can be achieved by manufacturing using a down-draw process. Such particularly smooth surfaces are obtained when the glass is given the opportunity to flow smoothly without contact with a forming surface before it solidifies. Experts refer to these as “fire-polished surfaces.” The roughness values ​​of mechanically polished surfaces are poorer. Furthermore, polishing marks are visible on mechanically polished surfaces under the atomic force microscope (AFM). Furthermore, residues of the mechanical polishing agent, such as diamond powder, iron oxide, and / or CeO2, can also be detected under the AFM. Since mechanically polished surfaces always have to be cleaned after polishing, certain ions leach out from the surface of the glass. This depletion of certain ions can be detected using secondary ion mass spectrometry (ToF-SIMS).Such ions include Ca, Zn, Ba and alkali metals.

[0102] The glass article may have a Vickers hardness of at least 540, at least 570, or at least 590. The Vickers hardness may be between 540 and 800, between 570 and 700, or between 590 and 630.

[0103] The glass article may 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 may 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 may be up to 1800 MPa, up to 1600 MPa, up to 1500 MPa, or up to 1400 MPa. For example, the compressive stress may 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.

[0104] In one embodiment, the glass article has a thickness of 20 to 40 pm, e.g., 25 to 35 pm, and has a compressive stress on one or both of its major surfaces of at least 800 MPa, at least 850 MPa, at least 900 MPa, or at least 900 MPa.

[0105] Optionally, the glass article has a DoL of 3 to 15 pm or 4 to 12 pm on one or both of its main surfaces. For example, the DoL may be at least 3 pm, at least 4 pm, at least 6 pm, at least 7 pm, or at least 8 pm. Alternatively or additionally, the DoL may be up to 15 pm, up to 13 pm, up to 12 pm, or up to 11 pm.

[0106] In one embodiment, the 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% of the article thickness, at least 12%, or at least 14% of the article thickness. The DoL may 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 at a considered surface. The total DoL of all compressive stress layers may be greater. One of the amazing properties of the glass article of this disclosure is that very high compressive stresses can be achieved even in thin glass articles. In embodiments, the glass article has, on one or both of its major surfaces, a ratio of compressive stress in MPa to article thickness in pm of at least 4.0 MPa / pm, at least 5.0 MPa / pm, at least 6.0 MPa / pm, or at least 10.0 MPa / pm.In embodiments, this value can be up to 40.0 MPa / pm, up to 35.0 MPa / pm, or up to 30.0 MPa / pm. Optionally, the ratio of compressive stress in MPa to article thickness in pm can be up to 10.0 MPa / pm, up to 8.0 MPa / pm, or up to 7.0 MPa / pm. In certain embodiments, the ratio of compressive stress in MPa to article thickness in pm is in the range from 4.0 MPa / pm to 40.0 MPa / pm, from 5.0 MPa / pm to 35.0 MPa / pm, from 5.0 MPa / pm to 30.0 MPa / pm, or from 10.0 MPa / pm to 29.0 MPa / pm. In a particular embodiment, this value ranges from 20.0 MPa / pm to 30.0 MPa / pm. In one embodiment, the ratio of the compressive stress in MPa to the thickness of the article is at least 20.0 MPa / pm or at least 25.0 MPa / pm.

[0107] Optionally, the glass article may have, on one or both of its major surfaces, a ratio of compressive stress at the surface in MPa to depth of the ion-exchanged layer (DoL) in pm of at least 50 MPa / pm, at least 75 MPa / pm, or at least 90 MPa / pm. In one embodiment, this value is even at least 100 MPa / pm, at least 120 MPa / pm, or at least 140 MPa / pm. For example, the ratio of compressive stress in MPa to depth of the ion-exchanged layer in pm may be between 50 and 400 MPa / pm, between 75 and 300 MPa / pm, or between 90 and 200 MPa / pm. In certain embodiments, the ratio of compressive stress in MPa to depth of the ion-exchanged layer in pm is up to 400 MPa / pm, up to 300 MPa / pm, or up to 200 MPa / pm.

[0108] In one embodiment, the glass article has excellent three-point bending strength, exhibiting a three-point bending 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 article after ion exchange is even more noteworthy. Optionally, the three-point bending 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 bending 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.

[0109] In one embodiment, the toughenable glass article has a low temperature toughening value LTT2oo M mOf at least 1150 MPa, at least 1200 MPa, at least 1250 MPa, or at least 1300 MPa. Optionally, the low-temperature tempering value is up to 1600 MPa, up to 1500 MPa, up to 1400 MPa, or up to 1375 MPa. The LTT2oopm can, in particular, be from 1150 MPa to 1600 MPa, from 1200 MPa to 1500 MPa, or from 1250 MPa to 1400 MPa.

[0110] In one embodiment, the temperable glass article has a mean tempering temperature value MTT2oo M m Of at least 1100 MPa, at least 1200 MPa, at least 1225 MPa or at least 1250 MPa. Optionally, the mid-temperature prestress value is up to 1500 MPa, up to 1400 MPa, up to 1350 MPa or up to 1300 MPa. The MTT 2O O M m can in particular be from 1100 M Pa to 1500 M Pa, from 1200 M Pa to 1400 M Pa or from 1200 M Pa to 1350 MPa.

[0111] In one embodiment, the temperable glass article has a low-temperature tempering value LTTsopm of at least 800 MPa, at least 850 MPa, at least 900 MPa, or at least 950 MPa. Optionally, the low-temperature tempering value LTTao m is up to 1400 MPa, up to 1300 MPa, up to 1100 MPa, or up to 1000 MPa. In particular, the LTTsopm can be from 800 MPa to 1400 MPa, from 900 MPa to 1300 MPa, or from 950 MPa to 1100 MPa.

[0112] In one embodiment, the temperable glass article has a mean temperature tempering value MTTsopm of at least 700 MPa, at least 750 MPa, at least 800 MPa, or at least 900 MPa. Optionally, the mean temperature tempering value MTTsopm is up to 1300 MPa, up to 1200 MPa, up to 1100 MPa, or up to 950 MPa. In particular, the MTTsopm can be from 700 MPa to 1300 MPa, from 800 MPa to 1200 MPa, or from 900 MPa to 1100 MPa.

[0113] In one embodiment, the toughenable glass article has a low-temperature diffusivity D L T of at least 4.0 pm 2 / h, at least 8.0 pm 2 / h, at least 10.0 pm 2 / h, at least 12.0 pm 2 / h or at least 14.0 pm 2 / h. Optionally, D L T maximum 100 pm 2 / h, maximum 80 pm 2 / h, maximum 60 pm 2 / h s maximum 40 pm 2 / h, maximum 25 pm 2 / h or at most 8 pm 2 / h. In one embodiment, the D L T from 4.0 pm 2 / h until 100 pm 2 / h, from 8.0 pm 2 / h until 60 pm 2 / h, from 10.0 pm 2 / h until 40 pm 2 / h or from 14.0 pm 2 / h until 25 pm 2 / h.

[0114] In one embodiment, the temperable glass article has a diffusivity D of at least 20.0 pm 2 / h, at least 25.0 pm 2 / h, at least 30.0 pm 2 / h or at least 40.0 pm 2 / h. Optionally, D is a maximum of 300 pm 2 / h, maximum 200 pm 2 / h, maximum 150 pm 2 / h s maximum 100 pm 2 / h, maximum 80 pm 2 / h or at most 70 pm 2 / h. In one embodiment, D is 20.0 pm 2 / h until 300 pm 2 / h, from 25.0 pm 2 / h until 800 pm 2 / h, from 25.0 pm 2 / h until 100 pm 2 / h or from 30.0 pm 2 / h until 80 pm 2 / h.

[0115] In particular, the glass article may have 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. 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 may 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.

[0116] 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.

[0117] Electronic device

[0118] The glass and / or glass article can be used in an electronic device, e.g., in 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 comprise a glass or glass article according to this disclosure. The electronic device can comprise 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.

[0119] The electronic device may be a flexible, bendable and / or foldable device, such as a flexible and / or foldable smartphone or a tablet computer.

[0120] One embodiment relates to an electronic device having at least one display and a display cover, wherein the display cover comprises or consists of a glass and / or a glass article according to this disclosure.

[0121] Manufacturing process

[0122] The glass can be produced by melting a mixture of raw materials suitable for achieving the properties described in this disclosure. The glass can be melted, for example, in a platinum crucible. After melting, the glass melt 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.

[0123] On an industrial scale, glass items can be manufactured using down-draw or overflow fusion processes. The down-draw process is preferred because it allows for very thin thicknesses.

[0124] After forming, the article can be hardened by ion exchange (also called "chemical strengthening" or "chemical toughening"). Hardening may involve immersing the article in a bath of molten salt. The salt is selected according to the desired ion exchange process. Preferably, the salt is potassium nitrate. In certain embodiments, the salt bath contains potassium nitrate, optionally about 100% KNO3.

[0125] 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 that exchange with 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, as the larger ions take up more space in the glass structure. Ion exchange significantly improves the strength of the glass. Furthermore, the compressive stress caused by chemical strengthening improves the bending properties of the tempered glass article and increases its scratch resistance. Typical salts used for chemical tempering include K +-containing salt melts or salt mixtures are used. Optional ion exchange baths for chemical tempering are Na + - and / or K + -containing salt melts 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. The ion exchange bath preferably 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 to increase chemical strength. The ion exchange can take place at temperatures in the range of 300°C to 500°C or 340°C to 490°C, in particular 340°C to 450°C or 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 Tg -100 °C or from T g -260 to T g -130 °C. Chemical strengthening is not limited to a single step. It can involve multiple steps in one or more salt baths with alkali metal ions of different concentrations and / or different ions in the salt baths to achieve better toughening performance. Thus, the chemically toughened glass can be toughened in one step or in multiple steps, for example, in two steps. Two-step chemical toughening is particularly used for Li2O-containing glasses, as lithium can be exchanged for both sodium and potassium ions.

[0126] 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 time the article is immersed in the ion exchange bath at the specified temperatures can be between 5 minutes and 12 hours, between 10 minutes and 4 hours, or between 20 minutes and 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.

[0127] In one embodiment, the method for producing a glass comprises the steps:

[0128] Providing glass raw materials suitable for obtaining a glass according to this disclosure,

[0129] Melting the glass raw materials to form a glass melt, optionally forming the glass melt to form a glass article, in particular in a drawing process, in particular in a down draw process or overflow fusion process,

[0130] Cooling the molten glass or optionally the glass article.

[0131] In one embodiment, the method also comprises chemically toughening the glass article, comprising the steps of:

[0132] Placing the glass article in an ion exchange bath,

[0133] Exchanging ions of the glass article to be exchanged with ions of the ion exchange bath at an ion exchange temperature, wherein the ions of the ion exchange bath at least partially have a higher 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.

[0134] Prestressing process

[0135] In one embodiment, this disclosure relates to a method for chemically toughening a glass article consisting of a glass according to this disclosure, comprising the steps:

[0136] Placing the glass article in an ion exchange bath,

[0137] Exchanging ions of the glass article to be exchanged with ions of the ion exchange bath at an ion exchange temperature, wherein the ions of the ion exchange bath at least partially have a higher ion diameter than the ions of the glass article to be exchanged.

[0138] 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 that exchange with 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, as the larger ions take up more space in the glass structure. After ion exchange, the strength of the glass is significantly improved. Furthermore, the compressive stress caused by chemical strengthening improves the bending properties of the tempered glass article and increases its scratch resistance. Typical salts used in chemical tempering include K + -containing salt melts or salt mixtures are used. Optional ion exchange baths for chemical tempering are Na + - and / or K +-containing salt melts 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. The ion exchange bath preferably 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 to increase chemical strength. The ion exchange can take place at temperatures in the range of 300°C to 500°C or 340°C to 490°C, in particular 340°C to 450°C or 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-130 °C. Chemical strengthening is not limited to a single step. It can involve multiple steps in one or more salt baths with alkali metal ions of different concentrations and / or different ions in the salt baths to achieve better toughening performance. Thus, the chemically toughened glass can be toughened in one step or in multiple steps, for example, in two steps. Two-step chemical toughening is particularly used for Li2O-containing glasses, as lithium can be exchanged for both sodium and potassium ions.

[0139] 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 time the article is immersed in the ion exchange bath at the specified temperatures can be between 5 minutes and 12 hours, between 10 minutes and 4 hours, or between 20 minutes and 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.

[0140] Uses

[0141] This disclosure also relates to the use of the glass and glass articles described herein. Glass articles or glasses of this disclosure can be used, for example, as or in displays, display covers, laminates, or wafers. The displays, display covers, laminates, or wafers can be bendable or foldable.

[0142] Exemplary embodiments

[0143] Some specific embodiments of the products and methods of this disclosure are presented below, which alone or in conjunction with the features described above are part of the subject matter of this disclosure.

[0144] In a first exemplary embodiment, this disclosure relates to a glass free of AS2O3 and Sb2O3, comprising in mol%: where the molar ratio Na2O / AI2O3 is from 1.35 to 1.50 and where the molar ratio SiO2 / (AI2C>3+ZrO2) is from 4.00 to 5.50.

[0145] In a second exemplary embodiment, this disclosure relates to a glass free of AS2OS and Sb2Os, comprising in mol%: wherein the molar ratio Na2O / AI2O3 is from 1.35 to 1.50 and wherein the molar ratio SiO2 / (AI2O3+ZrO2) is from 4.00 to 5.50, and wherein the glass has a low temperature tempering value LTT2oo Mm of at least 1150 MPa, a low temperature prestress value LTT3o M m of at least 800 MPa and a crystal growth rate of 10 5 dPa*s of less than 0.50 pm / min.

[0146] 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 Na2O / Al2O3 is from 1.35 to 1.75 and wherein the molar ratio SiO2 / (Al2O3+ZrO2) is from 3.00 to 4.90, wherein the glass comprises (in mol%):

[0147] 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 Na2O / AhO3 is from 1.35 to 1.75 and wherein the molar ratio SiO2 / (AhO3+ZrO2) is from 3.00 to 4.90, wherein the glass comprises (in mol%): and wherein the glass has a low temperature diffusivity DLT of at least 8.0 pm 2 / h and / or a crystal growth rate of 10 5 dPa*s of less than 0.50 pm / min.

[0148] 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 Na2O / AhO3 is from 1.35 to 1.75 and wherein the molar ratio SiO2 / (AhO3+ZrO2) is from 3.00 to 4.90, wherein the glass comprises (in mol%): and wherein the glass has a low-temperature diffusivity D L T of at least 12.0 pm 2 / h and / or a Krista II growth rate at 10 5 dPa*s of less than 0.20 pm / min.

[0149] In a sixth exemplary embodiment, this disclosure relates to a glass having the

[0150] Components SiO2, AlO3 and NaO2 and optionally ZrO2 and a low temperature prestress value LTTsopm of at least 8000 MPa, a low temperature diffusivity DLT of at least 8.0 pm 2 / h, a crystal growth rate of 10 5dPa*s of less than 0.50 pm / min, a mid-temperature prestress value MTkoopm of at least 1100 MPa.

[0151] 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 temper value LTT2oo M m of at least 11500 and at most 1500 MPa, a low-temperature diffusivity DLT of at least 12.0 pm 2 / h and a maximum of 20.0 pm 2 / h, a crystal growth rate of 10 5 dPa*s of less than 0.20 pm / min, a mid-temperature bias value MTT3o Mm of at least 800 MPa and at most 1300 MPa.

[0152] In an eighth exemplary embodiment, this disclosure relates to a glass having a low temperature temper value LTT2oo M m of at least 1150 MPa, a low-temperature diffusivity DLT of at least 8.0 pm 2 / h, a crystal growth rate of 105 dPa*s of less than 0.50 pm / min, a mid-temperature prestress value MTTsopm of at least 800 MPa, and a composition in mol% comprising

[0153] In a ninth exemplary embodiment, this disclosure relates to a glass having the

[0154] Components SiO2, Al2O3 and Na2O and optionally ZrO2 and a low-temperature prestress value LTT50pm of at least 800 and at most 1500 MPa, a low-temperature diffusivity DLT of at least 12.0 pm 2 / h and a maximum of 20.0 pm 2 / h, a crystal growth rate of 10 5 dPa*s of less than 0.20 pm / min, a mid-temperature prestress value MTkoopm of at least 1100 MPa and at most 1500 MPa, a composition in mol% comprising

[0155] A tenth exemplary embodiment of this disclosure relates to a glass article made of a glass according to any one of the first to ninth embodiments having a thickness of less than 100 pm, in particular having a thickness of 20 pm to 80 pm.

[0156] An eleventh exemplary embodiment of this disclosure relates to a glass article made of a glass according to any one of the first to ninth embodiments having a thickness of less than 100 pm, in particular having a thickness of 20 pm to 80 pm, which has on one or both of its main surfaces a surface roughness R a of at most 3.0 nm and an area of ​​at least 10 cm 2 has.

[0157] A twelfth exemplary embodiment of this disclosure relates to a glass article made of a glass according to any one of the first to ninth embodiments having a thickness of less than 100 pm, in particular having a thickness of 20 pm to 80 pm, which has a surface roughness R on one or both of its main surfaces. a of at most 3.0 nm and an area of ​​at least 10 cm 2 and has an ion-exchanged layer, in particular a compressive stress layer, on one or both of its main surfaces.

[0158] A thirteenth exemplary embodiment of this disclosure relates to a glass article made of a glass according to any one of the first to ninth embodiments having a thickness of less than 100 pm, in particular having a thickness of 20 pm to 80 pm, which has on one or both of its main surfaces a surface roughness R a of at most 3.0 nm and an area of ​​at least 10 cm 2and has a compressive prestress on at least one surface of at least 800 MPa.

[0159] In a fourteenth exemplary embodiment, this disclosure relates to an electronic device having at least one display and a display cover, wherein the display cover comprises or consists of a glass according to one of the first to ninth embodiments or a glass article according to one of the tenth to thirteenth embodiments.

[0160] Examples

[0161] Example 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 example glasses. The glasses were additionally refined with a small amount of SnO2 (approximately 0.04 mol%). The values ​​in the tables are rounded to one decimal place. Due to rounding differences, the ingredients do not always add up to exactly 100.0%.

[0162] Thin glass sheets were produced from these compositions. The sheet thickness was 200 μm. The sheets were then chemically strengthened in a 100% KNO3 salt bath at 440 °C for 30 minutes or at 390 °C for 45 minutes.

[0163] Example glass compositions

[0164]

[0165] Comparative compositions

[0166]

[0167] *These samples were fully crystallized with a CWR well above 0.5 pm / min (outside the measuring range).

[0168] 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 pm / 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 temper values ​​MTT30min / KNO3 of Comparative Glasses I to IV are significantly higher than those of Examples A to F. The thicknesses of the ion-exchanged DOLMTT layer are thinner in the Comparative Examples.

[0169] Comparative Examples V, VI, and VII demonstrate that, although good resistance to crystallization can be achieved when the SiO2 / (AhO3+ZrO2) ratio is exceeded, the mid-temperature prestress values ​​are very low. Results for low-temperature prestress are also available for Comparative Examples V, VI, and VII:

[0170] Here, too, it becomes clear that high prestresses cannot be achieved.

[0171] In a further experiment, glass E was tank-melted and drawn to a thickness of 32 μm. This glass was subjected to chemical tempering with 100% KNO3. A compressive stress of over 950 MPa was achieved. A review of these experimental data shows that the inventors have found a composition range for aluminosilicate glasses that combines a variety of properties important for thin and ultra-thin display glasses. These advantageous glasses can be tempered to remarkably high CS values ​​and yet are sufficiently resistant to crystallization to be processed using down-draw processes. A compressive stress of over 900 MPa in a 32 μm thick glass article was previously simply unimaginable with a glass that could be produced on an industrial scale.It is particularly surprising that such great values ​​can be achieved in a glass system that has been so extensively researched as that of aluminosilicates, and this without the addition of difficult-to-handle, toxic or particularly expensive components.

[0172] Crystallization experiment

[0173] To gain a visual impression of the crystallization properties of the glasses, glass samples were kept at different temperatures for 16 hours each. The samples were then visually inspected for crystal formation.

[0174] The images show photomicrographs of glass samples at approximately 100x magnification.

[0175] Figure 1 shows the result of heat treatment of a glass sample of composition A at 1010 °C, which corresponds to a viscosity of 10 55dPa*s. Due to a very low crystal II growth rate, only very small crystals of approximately 1 pm in size are visible.

[0176] Figure 2A shows the result for example composition B after heat treatment at 1140 °C, which corresponds to a viscosity of 10 46 dPa*s. Figure 2B shows the result at 1060 °C, corresponding to a viscosity of 10 52 dPa*s. No crystals are visible in the images.

[0177] Figure 3 shows a sample of composition E with a very low crystal growth rate at 1010 °C, corresponding to 10 58 dPa*s. Only very few and very small crystals were formed (up to 4.7 pm).

[0178] Figure 4 shows a sample of comparative composition III after heat treatment at 1060 °C, which corresponds to a viscosity of 10 5 14dPa*s. The sample is completely crystallized, corresponding to an estimated crystal growth rate of >0.5 pm / min.

Claims

Claims 1. Glass free of AS2O3 and Sb2C>3, comprising in mol% where the molar ratio Na2O / AI2O3 is from 1.35 to 1.75 and where the molar ratio SiO2 / (AI2O3+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% 5. Glass according to at least one of the preceding claims having a low-temperature diffusivity DLT of at least 4.0 pm 2 / h, at least 8.0 pm 2 / h, at least 10.0 pm 2 / h, at least 12.0 pm 2 / h or at least 14.0 pm 2 / h.

6. Glass according to at least one of the preceding claims with a low-temperature tempering value LTT 20 O Mm Of 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 having a low temperature tempering value LTTsopm 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 pm / min, less than 0.20 pm / min, less than 0.10 pm / min, less than 0.05 pm / min or less than 0.02 pm / 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%:

11. Glass according to at least one of the preceding claims having the following composition in mol%:

12. A glass article comprising a glass according to any one of the preceding claims or consisting thereof, wherein the glass article has at least in sections a thickness of less than 300 pm, in particular of less than 100 pm.

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 method 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 glass melt into a glass article, Cooling the molten glass or optionally the glass article.

16. A method according to claim 15, comprising the further step of chemically toughening the glass or glass article by ion exchange.

Images