Plate-shaped, chemically temperated or chemically temperatable

Abstract

The invention relates to a plate-like chemically tempered or at least chemically temperable glass article and to a method for producing the glass article. In addition, the invention also relates to a glass composition.

Description

[0001] This invention application is a divisional application of Chinese patent application CN202010772417.5. Technical Field

[0002] The present invention relates to a plate-shaped, chemically toughened or at least chemically toughenable glass product and a method for producing the glass product. Background Art

[0003] Sheet-shaped tempered glass, in particular chemically tempered and highly chemically tempered glass, is used in particular as so-called cover glass (or protective cover or cover glass) for mobile devices such as smartphones or tablets. Compared to cover panels made of transparent plastic, these cover glasses are particularly scratch-resistant, but also have a higher weight.

[0004] Generally speaking, only chemically tempered plate-shaped glass products are used as cover glass for mobile terminal devices. This is because these glass products are more resistant to mechanical abrasion loads, that is, they have the wear resistance required for the application. In the present disclosure, wear resistance refers to the resistance of a product (or article, such as a glass article or glass product) to mechanical loads, in particular to abrasion loads, scratch loads, or impact loads. In the present disclosure, the term wear resistance or simply strength is used as a general term for the mechanical resistance of a product or article. Special forms of wear resistance or simply strength are, for example, scratch resistance, bending strength, or impact resistance, where it has been shown that these loads can also be related, and this is particularly important in practical applications. Such practical loads are, for example, collisions with rough surfaces, especially in the installed state.

[0005] However, in addition to good wear resistance, sheet glass products must meet other requirements. In particular, the glass they comprise must be easy to manufacture, meaning it must be capable of being melted, for example, with subsequent hot forming, preferably without devitrification. Chemical resistance, particularly acid resistance, is also important. In this context, while the final product must exhibit good resistance, it must also be readily temperable using ion exchange methods.

[0006] For example, in the patent family of US 2019 / 0016632A1 with the granted US patent US 9,593,42 B2 as the same patent family, the patent family of US 2018 / 0057401 A1 with the granted US patent US 10,294,151 B2 as the same patent family, the patent family of US2018 / 0029932 A1 with the granted US patent US 10,259,746 B2 as the same patent family, the patent family of US2017 / 0166478 A1 with the granted US patent US 9,908,811 B2 as the same patent family, the patent family of US 2016 / 0122240 A1 with the granted US patent US 10,239,784 B2 as the same patent family, the patent family of US 2016 / 0122240 A1 with the granted US patent US 10,150,698 B2 as the same patent family. Patent family of US 2016 / 0122239 A1, patent family of US 2017 / 0295657 A1 with issued US patent US 10,271,442 B2 as a family patent, patent family of US 2010 / 0028607 A1 with issued US patent US 8,312,739 B2 as a family patent, patent family of US 2013 / 0224492 A1 with issued US patent US 9,359,251 B2 as a family patent, patent family of US 2016 / 0023944 A1 with issued US patent US 9,718,727 B2 as a family patent, patent family of US 2012 / 0052271 A1 with issued US patent US 10,227,253 B2, patent family of US 2012 / 0052271 A1 with issued US patent US 10,227,253 B2 as a family of patents in the patent family US 2015 / 0030840 A1, a family of patents in the patent family US 2014 / 0345325 A1, with issued U.S. Patent US 9,487,434 B2 as a family of patents in the patent family US 2016 / 0257605 A1, with issued U.S. Patent US 9,517,968 B2 as a family of patents in the patent family 2015 / 0239776 A1, with issued U.S. Patent US 9,567,254 B2 as a family of patents in the patent family US 2015 / 0259244 A1, with issued U.S. Patent US 9,676,663 B2 as a family of patents in the patent family US 2017 / 0036952 A1, with issued U.S. Patent US 10,266,447 B2 is a patent family of the same patent US 2018 / 0002223 A1, with the granted US patent US 9,517,968 B2 as a family of patents in the same family as US 2017 / 0129803 A1, US 10,266,447 B2 as a family of patents in the same family as US 2016 / 0102014 A1, US 9,676,663 B2 as a family of patents in the same family as US 2015 / 0368153 A1, US 9,902,648 B2 as a family of patents in the same family as US 2015 / 0368148 A1, US 10,118,858 B2 as a family of patents in the same family as US 2015 / 0239775 A1, US 9,908,812 B2, US 2016 / 0264452 A1, and US 9,908,812 B2. 9,902,648 B2, US 2016 / 102011 A1 and the granted US Patent 9,593,042 B2, WO 2012 / 126394 A1, US 2014 / 0308526 A1 and the granted US Patent 9,540,278 B2, US 2011 / 0294648 A1 and the granted US Patent 8,759,238 B2, US 2010 / 0035038 A1 and the granted US Patent 8,075,999 B2, US 4,055,703, DE10 2010 009 584 A1 and the granted German Patent DE 10 2010 009 584 B4 and the patent family of U.S. patent application US 2016 / 0347655 A1 with granted U.S. patent US10351471 B2, the patent family of CN 102690059 A and granted Chinese patent CN 102690059 B, the patent family of US 2016 / 0356760 A1 and granted U.S. patent US10,180,416 B2, the patent family of WO2017 / 049028 A1 with granted U.S. patent US 9,897,574 B2 as a similar patent, the patent family of WO 2017 / 087742 A1, the patent family of US 2017 / 0291849 A1 and granted U.S. patent US10,017,417 B2, the patent family of US 2017 / 0022093 A1 and granted U.S. patent US9,701,569 B2's patent family, US2017300088 (A1) and the authorized US patent US 9,977,Known chemically toughened glasses and / or chemically toughened or chemically toughened glass products and / or methods for producing such products are described in the patent family of EP 1 593 658 A1, the granted European patent EP 1 593 658 B1, the US patent applications US 2005 / 0250639 A1 and US 2018 / 0022638 A1, and the granted US patent US 10,183,887 B2. Chemically toughened glasses can be divided into so-called aluminosilicate glasses (also known as AS glasses, aluminosilicate glasses, or aluminosilicate glasses) containing, in particular, Al2O3 and SiO2 and alkali metal oxides other than lithium oxide Li2O as components, and lithium aluminosilicate glasses (also known as LAS glasses, lithium aluminosilicate glasses, or lithium aluminosilicate glasses) that further contain Li2O as a component.

[0007] In the patent family of US 2019 / 0152838 A1, the patent family of US 2013 / 0122284 A1 and the issued US Patent US9,156,724 B2, the patent family of US 2015 / 0079400 A1 with the issued US Patent US9,714,188 B2, the patent family of US 2015 / 0099124 A1 and the issued US Patent US9,701,574 B2, the patent family of WO2019 / 085422 A1, the patent family of US 2017 / 0197869 A1 and the issued US Patent US10,131,567 B2, the patent family of US 2015 / 0030840 A1 and the issued US Patent US10,227,253 B2, the patent family of US2015 / 0140325 Other prior art documents can be found in the patent family of US 2015 / 0118497 A1 and the granted US patent US 9,822,032 B2, the patent family of US 2012 / 0135852 A1 and the granted US patent US 8,796,165 B2, the patent family of US 2015 / 0147575 A1 and the granted US patent US 10,000,410 B2, and the patent family of US 2015 / 0376050 A1 and the granted US patent US 9,783,451 B2.

[0008] These glasses are designed so that they can be chemically toughened. In the present disclosure, chemically toughened glass refers to glass that can be subjected to an ion exchange process. In this process, alkali metal ions are exchanged in the surface layer of a glass article (e.g., a glass sheet). This is achieved by creating a compressive stress zone in the surface layer by exchanging ions with larger radii for ions with smaller radii. To this end, the glass article is immersed in a so-called ion exchange bath, for example, a molten salt, containing ions with larger ionic radii, particularly potassium and / or sodium ions, so that these ions migrate into the surface layer of the glass article. In exchange, ions with smaller ionic radii, particularly lithium and / or sodium ions, migrate from the surface layer of the glass article into the ion exchange bath.

[0009] This results in a compressive stress zone. This compressive stress zone can be described by the characteristic parameters of compressive stress (also known as "compressive stress" or "CS") and the compressive stress depth (also known as "Depth of Layer" or "DoL"). The compressive stress depth DoL is well known to those skilled in the art and, in this disclosure, refers to the depth at which a stress curve has a stress zero crossing. Alternatively or additionally, the DoL thickness can be determined using a stress-optical zero-crossing measurement method, for example, using measurement equipment marketed as the FSM-6000 or SLP 1000.

[0010] The measuring device can also be used to determine the surface compressive stress and the maximum compressive stress CS of a plate or plate-shaped glass product for aluminosilicate glass.

[0011] Glasses known from the prior art generally contain a high content of alkali metal oxides as components. This was previously considered necessary to enable the glass products to be prestressed with high compressive stresses. A high alkali metal oxide content also leads to a lower melting temperature.

[0012] However, there is a conflict of objectives. State-of-the-art temperable glasses are generally fusible and ion-exchangeable. However, on the one hand, long exchange times are required to generate the desired high compressive stresses on the surface of the glass article. On the other hand, a high alkali metal oxide content is generally disadvantageous for the chemical resistance of the glass article, for example, hydrolytic and / or acid resistance.

[0013] Therefore, there is a need for plate-shaped glass products that can be designed to be highly chemically toughened and at the same time fusible and acid-resistant. Accordingly, there is a need for chemically toughened plate-shaped glass products that have high compressive stress and preferably good acid resistance. Summary of the Invention

[0014] The object of the present invention is to provide a sheet glass product, in particular a chemically toughenable or chemically toughened sheet glass product, which at least reduces the disadvantages of the prior art.

[0015] This object is achieved by the subject matter of the independent claim. More detailed solutions are provided in the dependent claims.

[0016] Thus, the present disclosure relates, according to a first aspect, to a chemically toughened or at least chemically toughenable sheet-like glass product, comprising glass having a composition comprising Al2O3, SiO2, Na2O and preferably Li2O, the glass product preferably having at least one of the following features: - the glass comprises up to 6% by weight of Na2O, preferably up to 5.5% by weight of Na2O, particularly preferably up to 4.5% by weight of Na2O and preferably at least 0.8% by weight of Na2O, and / or - the glass article has a prestress or prestressability CS of at least 250 MPa / g Na2O, relative to the weight ratio of Na2O in the glass article, per 100 g of glass. The prestressability is preferably at most 1500 MPa / g Na2O, particularly preferably at most 1000 MPa / g Na2O, per 100 g of glass.

[0017] This solution for glass products has a number of advantages.

[0018] By including a glass article having a composition of Al2O3, SiO2, and Na2O, the sheet-shaped glass article is first configured to be chemically toughenable. In this case, the glass included in the glass article is AS glass or even LAS glass. Specifically, the glass article is preferably designed such that the glass includes Li2O. It is well known that such AS and LAS glasses can be chemically hardened or toughened by ion exchange.

[0019] In this embodiment, the glass contains up to 6% by weight of Na2O, preferably up to 5.5% by weight of Na2O, and particularly preferably even only up to 4.5% by weight of Na2O. A low Na2O content is particularly advantageous for acid resistance. This is because alkali metal oxides can leach out of the glass, with sodium ions being more susceptible to leaching than, for example, lithium ions due to their lower field strength. Therefore, the Na2O content is limited.

[0020] This low content in glass, or correspondingly in glass articles containing glass, is also advantageous in the context of glass article manufacturing, particularly during chemical tempering. Since the glass contains relatively little NaO, the exchange bath is only slightly contaminated by sodium ions entering the bath from the glass. This is therefore advantageous for the economics of the manufacturing process.

[0021] However, the glass or glass product containing the glass should have a minimum NaO content. This is necessary so that the glass can undergo ion exchange, in particular so-called potassium exchange. Furthermore, this also increases the meltability of the glass. The glass or glass product preferably contains at least 0.8% by weight of NaO.

[0022] Surprisingly, however, a good compressive prestress can still be achieved with such a low Na2O content of at least only 0.8% by weight. In particular, a compressive prestress (CS) of at least 600 MPa and not more than 1000 MPa is achieved due to the potassium exchange.

[0023] Alternatively or additionally, the glass article is designed such that, for 100 g of glass, it has a prestress or at least a prestressability of at least 250 MPa / g Na2O relative to the weight ratio of Na2O in the glass or glass article. For 100 g of glass, this prestressability is preferably at most 1500 MPa / g Na2O, particularly preferably at most 1000 MPa / g Na2O.

[0024] In other words, in this case, the glass or the glass article is designed such that it has a large stress with respect to the sodium oxide contained in the glass or the glass article.

[0025] In the present disclosure, prestressability refers to the ability of glass or glass products to be highly tempered, in particular the ability to absorb and store introduced stress. In the present disclosure, a prestress of at least 400 MPa is referred to as high prestress.

[0026] Until now, it was assumed that a high absolute number of alkali ions in the glass or glass product was necessary in order to facilitate prestressing of the glass or glass product comprising the glass, or to achieve a high degree of chemical toughening of the glass product to achieve a prestress of at least 400 MPa or preferably at least 600 MPa, in particular for glass thicknesses of at least 0.4 mm to 3 mm. However, it was surprisingly found that good prestressability can be ensured even with only a low content of exchanged alkali ions.

[0027] There are two aspects worth noting here: When alkali ions, particularly sodium ions, are readily ion-exchangeable, a low absolute content of the alkali ions to be exchanged (here, particularly sodium ions) has been shown to enable sufficient, even high, prestressing forces of at least 600 MPa to even 1000 MPa, particularly for glass thicknesses of at least 0.4 mm to 3 mm. This first aspect relates to the exchangeability of the alkali ions contained in the glass or glass article. The inventors believe that prestressing forces exceeding 1000 MPa can even be achieved.

[0028] Alternatively or additionally, however, the prestressability of the glass matrix is ​​also important, which means that it is not or not only or not only the exchangeability of the alkali ions to be exchanged that is important, but also the structure and / or the ability of the glass matrix to store prestress.

[0029] If both conditions are met, i.e. if the majority of the alkali ions comprised by the glass are readily exchangeable and at the same time the glass matrix is ​​suitable for forming and / or storing high initial stresses, then even a relatively small proportion of alkali ions to be exchanged can be sufficient to still achieve a highly chemically toughenable or chemically toughened glass article with particular advantage.

[0030] In this disclosure, the following provisions apply: An exchange bath is understood to be a molten salt, wherein the molten salt is used in an ion exchange process for glass or glass products. In the present disclosure, the terms exchange bath and ion exchange bath are used synonymously.

[0031] Typically, technically pure salts are used for the exchange bath. This means that, even if, for example, only sodium nitrate is used as the starting material for the exchange bath, the bath still contains certain impurities. In this case, the exchange bath is a melt of a salt (e.g., sodium nitrate) or a mixture of salts (e.g., a mixture of sodium and potassium salts). In this case, the composition of the exchange bath is specified so that it relates to the nominal composition of the exchange bath, without taking into account any impurities that may be present. Therefore, in this disclosure, reference to a 100% sodium nitrate melt indicates that only sodium nitrate was used as the starting material. However, the actual sodium nitrate content of the exchange bath may differ, and often does, since, in particular, industrial raw materials contain a certain amount of impurities. However, this amount is typically less than 5 parts by weight, in particular less than 1 part by weight, relative to the total weight of the exchange bath.

[0032] Accordingly, when using an exchange bath containing a mixture of different salts, the nominal contents of these salts are specified without taking into account the limited industrial impurities in the starting raw materials. For example, an exchange bath containing 90 parts by weight of KNO and 10 parts by weight of NaNO may still contain small amounts of impurities, but these impurities are caused by the raw materials and should generally be less than 5 parts by weight, in particular less than 1 part by weight, relative to the total weight of the exchange bath.

[0033] Furthermore, the composition of the exchange bath may change during the ion exchange process, as lithium ions, in particular, migrate from the glass or glass product into the exchange bath due to the ongoing ion exchange. However, unless expressly stated otherwise, changes in the composition of the exchange bath due to aging are not considered herein. Specifically, in this disclosure, when specifying the composition of the exchange bath, the nominal initial composition applies.

[0034] In this disclosure, a stress distribution refers to a line in a stress diagram within a glass article (e.g., a glass sheet) over the thickness of the glass article in question. In this disclosure, when referring to a compressive stress distribution, this refers to a portion of the stress distribution in which stress is positive, i.e., greater than zero. Tensile stress, on the other hand, has a negative sign. This relates to the convention for stress signs commonly used by those skilled in the art, i.e., developers of tempered protective glass. This convention differs significantly from the conventional notation commonly used in physics, for example, which designates compressive stress as negative and tensile stress as positive. However, in this disclosure, as described above, the stress convention commonly used in the glass industry is employed.

[0035] In the present disclosure, a composite compressive stress distribution refers to a compressive stress distribution under which the compressive stress generated in a corresponding article (eg, a glass article) consists of at least two sub-regions.

[0036] The compressive stress stored in the tempered glass article is generated as the integral of the compressive stress over the thickness of the glass article. In this disclosure, this integral is referred to as the compressive stress integral.

[0037] The tensile stress stored in a tempered glass article is generated as the integral of the tensile stress over the thickness of the glass article. In this disclosure, this integral is referred to as the tensile stress integral. Therefore, in this disclosure, the terms stored tensile stress and tensile stress integral may also be used synonymously.

[0038] In the present disclosure, a sheet-like glass article is understood to mean a glass article in which the lateral dimension in one spatial direction is at least one order of magnitude smaller than the lateral dimensions in the other two spatial directions, wherein the spatial directions are given relative to a Cartesian coordinate system in which the spatial directions extend perpendicularly to one another and in which the thickness is therefore measured from one main surface to the other in a direction perpendicular to the largest or main surface.

[0039] The thickness is at least one order of magnitude smaller than the width and length of the glass article. Therefore, in this case, the width and length may be of the same order of magnitude. However, the length of the glass article may also be much greater than its width. Therefore, in the present disclosure, a sheet-like glass article may also include a glass ribbon.

[0040] In the present disclosure, glass is understood as a material, and a glass product is understood as a product made of and / or comprising a glass material. A glass product can in particular consist of glass or essentially comprise a glass material, i.e. comprise at least 90% by weight of a glass material.

[0041] In this disclosure, chemical tempering is understood to mean a process in which a glass article is immersed in a so-called exchange bath. In this process, ion exchange occurs. In this disclosure, potassium exchange is understood to mean the migration of potassium ions from the exchange bath into the glass article, particularly into the surface of the glass article, i.e., for example, their embedding into the surface of the glass article, while simultaneously small alkali ions, such as sodium, migrate from the glass article into the exchange bath. Similarly, sodium exchange is understood to mean the migration of sodium ions from the exchange bath into the surface of the glass article, while small ions, such as lithium ions, migrate from the glass article, particularly from the surface of the glass article, into the exchange bath. As described above, this ion exchange generates compressive stress zones in the surface region of the glass article.

[0042] In the present disclosure, the maximum tensile stress is understood to be the minimum stress value in the stress distribution of the glass article.

[0043] In the present disclosure, a "sharp impact" is understood to be a load at which damage is caused by a relatively small sharp object or a plurality of such relatively small sharp objects. In other words, this is an impact caused by one or more sharp objects, i.e., for example, by particles with a very small radius of curvature or particles in which the angle of the tip is less than 100°.

[0044] If the grit size of sandpaper is used in this disclosure, it is preferably specified in accordance with DIN ISO 6344. This grit size is based on the measurement unit mesh. The larger the grit size, the smaller the abrasive particles. In this disclosure, for example, the terms "60 grit" and "#60" are used synonymously to designate grit sizes, for example, 60 grit. This, of course, applies to other grit sizes, such as 100 or 180 grit.

[0045] In the present disclosure, the term "ionic field strength" according to Dietzel is used. This term is used in particular for oxide glass matrices, wherein the value can vary depending on the coordination number of the ions involved.

[0046] The terms network modifier and network former are to be understood according to the theory of Zachariasen.

[0047] In this context, in the present disclosure, in particular the following substances are referred to as network formers: SiO 2 , Al 2 O 3 , B 2 O 3 , P 2 O 5 .

[0048] In particular, alkali metal oxides and alkaline earth metal oxides are referred to as network modifiers.

[0049] In particular, ZrO2 is referred to as a so-called intermediate oxide.

[0050] Glass according to embodiments of the present disclosure or sheet-shaped, chemically toughenable or chemically toughened glass products according to embodiments of the present disclosure can also be designed, in particular, to contain up to 6% by weight of Na2O, preferably up to 5.5% by weight of Na2O, particularly preferably up to 4.5% by weight of Na2O, with the minimum Na2O content preferably being at least 0.8% by weight, and wherein the glass product has a prestress or at least prestressability of at least 250 MPa / g Na2O relative to the weight ratio of Na2O of the glass or glass product per 100 g of glass. This prestressability is preferably up to 1500 MPa / g Na2O, particularly preferably up to 1000 MPa / g Na2O per 100 g of glass.

[0051] This is particularly advantageous for achieving good acid resistance of the glass or glass product, wherein the glass product is provided or can be designed to be highly chemically toughened.

[0052] It is not yet fully understood why a high degree of chemical toughening can be achieved or has been achieved with only very low Na2O contents in the glass or glass products, but it can be suspected that the reason lies in the selective adjustment of the glass matrix or the glass network.

[0053] According to one embodiment of the glass article, the glass comprises the other compositional components given in the present disclosure, however, the glass comprises at least 57% by weight of SiO2, preferably at least 59% by weight of SiO2, particularly preferably at least 61% by weight of SiO2 and / or the glass comprises up to 69% by weight of SiO2, preferably up to 67% by weight.

[0054] As a glass component, SiO2 is a so-called network former. A high SiO2 content in a glass improves its chemical resistance, particularly its acid resistance, and is therefore advantageous. It is also known that quartz glass SiO2 forms a very rigid, three-dimensional, crosslinked glass network. Therefore, according to one embodiment of a glass or glass product that also includes the other components disclosed herein, the SiO2 content is at least 57 parts by weight, preferably even at least 59 parts by weight, and particularly preferably at least 61 parts by weight. However, an excessively high SiO2 content in the glass can make it difficult to melt.

[0055] Therefore, according to the embodiments disclosed herein, the SiO 2 content of the glass is limited and is at most 69 wt %, preferably at most 67 wt %.

[0056] As a glass component, Al2O3, like SiO2, is a network former. In glasses and glass products according to embodiments, a minimum Al2O3 content within the aforementioned limits is advantageous. Because the addition of Al2O3 reduces the amount of non-bridging oxygen in alkali-containing silicate glasses, a rigid network can be achieved despite a certain glass content. Forming a relatively rigid glass network has been shown to contribute to the prestressability of alkali-containing glasses.

[0057] However, according to one embodiment having the other compositional components specified in this disclosure, the Al2O3 content of the glass or glass article is also limited. This is because excessive Al2O3 can lead to a decrease in the glass's acid resistance, in particular. Therefore, according to this embodiment, the Al2O3 content of the glass or glass article is preferably at least 17% by weight and / or at most 25% by weight, preferably at most 24% by weight, and particularly preferably at most 21% by weight.

[0058] In general, it has been shown that a high content of network formers in the glass or glass product, in particular a high content of the network formers SiO2 and Al2O3 in the glass, in particular relative to the weight ratio of Na2O in the glass or glass product, can achieve particularly good prestressability of the glass or glass product or a particularly high degree of chemical toughening. According to a preferred embodiment of the glass or glass product, the network former content of the glass or glass product is at least 82% by weight and / or the total content of Al2O3 and SiO2 in the glass or glass product is at least 75% by weight. This means that a high content of network formers in the glass or glass product, in particular a high content of the network formers SiO2 and Al2O3, clearly results in a glass structure that is particularly well able to store stress. Although the Al2O3 content of the glass reduces the number of non-bridging oxygens in the glass network, sufficient acid resistance can still be achieved. This is presumably due to the interaction between the low absolute alkali content, in particular the low sodium oxide content, and the overall high content of network formers.

[0059] If the network former content of the glass or glass product is further increased, the prestressability can be further increased. However, the network former content of the glass or glass product is preferably limited. According to one embodiment having the other components disclosed herein, the sum of the contents of SiO2 and Al2O3 is not more than 92 parts by weight, preferably not more than 90 parts by weight. The total content of network formers in the glass and / or glass product is particularly preferably not more than 92 parts by weight, particularly preferably not more than 90 parts by weight. This is advantageous because it allows for a glass that is still fusible and can therefore be produced cost-effectively.

[0060] As mentioned above, an important aspect of prestressability is that the alkali ions to be exchanged (here, in particular sodium ions) are also present in an exchangeable form. However, this leads to a conflict of objectives, since a high mobility of alkali ions can also result in only low chemical resistance, in particular low acid resistance, of the glass or glass product. Therefore, the alkali metal oxide content of the glass or glass product should not be too high.

[0061] According to one embodiment, the total alkali metal oxide content of the glass and / or glass product is preferably at least 4% by weight and at most 12% by weight, preferably at most 10% by weight.

[0062] Li2O is an optional component of the glass or glass article according to embodiments disclosed herein. Surprisingly, even when Li2O itself does not participate in ion exchange, i.e., when only potassium exchange occurs, Li2O as a component of the glass or glass article has a positive impact on the prestressability or prestress of the glass or glass article. This is because Li2O is a component that helps form a more rigid glass network. Therefore, the Li2O content of the glass or glass article is preferred according to one embodiment of the glass or glass article.

[0063] The LiO content of the glass or glass product allows for mixed ion exchange, in this case with sodium ions. This is preferred because it allows for chemically toughened or chemically tempered glass products to be obtained, which have particularly advantageous mechanical properties when subjected to the so-called set-drop test, for example. According to a preferred embodiment, the glass or glass product can contain at least 3 parts by weight, preferably at least 3.5 parts by weight.

[0064] Therefore, according to another embodiment of the glass article or glass, the glass or glass article preferably has a Li2O content of at least 3 parts by weight, particularly preferably at least 3.5 parts by weight and up to 5.5 parts by weight, preferably up to 5.0 parts by weight. This is advantageous, since a high Li2O content in the glass or glass article can lead to increased crystallization or segregation.

[0065] Another optional component of the glass or glass product is B2O3. A certain B2O3 content in the glass can be advantageous because it lowers the melting point of the glass and thus increases its solubility. It is known that the B2O3 component also increases the scratch resistance of the glass. Surprisingly, however, an excessively high B2O3 content in the glass or glass product can reduce prestressability. Therefore, according to one embodiment having the other compositional components disclosed herein, the glass and / or glass product has a B2O3 content of up to 7 parts by weight, preferably up to 5 parts by weight, and particularly preferably up to 4.5 parts by weight.

[0066] PO is another optional component of the glass and / or glass product according to the embodiments disclosed herein. The PO content of the glass and / or glass product can be advantageous because PO as a glass component can achieve a deeper prestress in a shorter time. In this way, the exchange process can be accelerated, so PO can be advantageous. However, a high PO content in the glass is disadvantageous because PO may corrode the material of the melting device. Therefore, the content of the glass and / or glass product according to the embodiments should be at most 3 parts by weight, preferably at most 2 parts by weight, and particularly preferably at most 1.7 parts by weight.

[0067] According to another embodiment of the chemically toughened or chemically toughenable plate-shaped glass product, the glass product comprises glass, and the glass comprises the following components measured in parts by weight: SiO257 to 69, preferably 59 to 69, particularly preferably 61 to 69, wherein the upper limit is preferably 67, Al2O3 17 to 25, preferably 17 to 24, particularly preferably 17 to 21, B2O30 to 7, preferably 0 to 5, particularly preferably 0 to 4.5, Li2O3 to 5.5, preferably 3.5 to 5.5, particularly preferably 3.5 to 5, Na2O 0.8 to 6, preferably 0.8 to 5.5, or even most preferably 0.8 to 4.5, For the data expressed in % by weight, the sum of the contents of Al2O3 and SiO2 is preferably between at least 75 and a maximum of 92, preferably a maximum of 90.

[0068] By combining the components in the manner described above, a glass product is obtained that is surprisingly highly chemically toughenable or chemically toughened and exhibits sufficient acid resistance while maintaining good meltability. This is presumably due to the interaction between the low content of alkali ions with low field strength (here, Na2O) in the glass or glass product and the aforementioned content of network formers in the glass or glass product. However, sufficient meltability is still achieved by the alkali metal oxide content in the glass, which is at least 4 parts by weight. The high prestressability of the glass or glass product according to this embodiment can be further enhanced by a Li2O content within the aforementioned limits, since lithium ions, due to their higher field strength compared to other network modifiers, advantageously assist in the formation of a rigid glass network. At the same time, lithium ions are more firmly incorporated into the glass matrix than other alkali ions, which can also improve acid resistance.

[0069] According to one embodiment of the plate-shaped glazing, the thickness of the glazing is between at least 0.4 mm and at most 3 mm, wherein the thickness is preferably at least 0.5 mm and / or preferably at most 2.0 mm, preferably at most 1.0 mm.

[0070] The glass articles according to embodiments of the present disclosure have an acid resistance determined as half the weight loss per unit area in a test according to or in accordance with DIN 12116, in units of mg / dm 2 , and the acid resistance is not greater than 15 mg / dm 2 That is, for the glass and / or glass article according to the embodiment, half of the weight loss per unit area does not exceed 15 mg / dm 2 .

[0071] A second aspect of the present disclosure relates to a glass product, in particular a glass product according to one embodiment of the present disclosure, in particular a glass product according to the first aspect of the present disclosure, which can be obtained by a method comprising the following steps: - an optional first ion exchange is carried out in an exchange bath comprising at least 20% and at most 100% by weight of a sodium salt, preferably sodium nitrate NaNO3, at a temperature between a minimum of 380°C and a maximum of 440°C, for a duration of at least 2 hours, preferably at least 4 hours and at most 24 hours, wherein a potassium salt, in particular potassium nitrate, can optionally be added to the exchange bath, in particular in such a way that the sum of the sodium and potassium salt contents amounts to 100%, - and carrying out the ion exchange in an exchange bath comprising between 0 and 10 parts by weight of sodium salt, preferably sodium nitrate NaNO 3 , relative to the total amount of salts, at an exchange bath temperature of at least 380° C. and at most 440° C., for a duration of at least one hour and at most six hours, wherein a potassium salt, particularly preferably potassium nitrate KNO 3 , is added to the exchange bath, in particular in such a manner that the sum of the sodium and potassium salt contents amounts to 100 parts by weight, and optionally including one or more further ion exchange steps.

[0072] This means that once the sodium is ion-exchanged with the lithium, this ion exchange is carried out as a first step in an exchange bath comprising at least 20% and up to 100% by weight of a sodium salt (preferably sodium nitrate NaNO 3 ), but this step is only optional, i.e. it is not necessarily mandatory.

[0073] However, it is essential that the potassium-sodium ion exchange step is carried out in an exchange bath containing between 0 and 10 wt.-% of sodium salt, preferably sodium nitrate NaNO 3 , relative to the total amount of salts, wherein a potassium salt, particularly preferably potassium nitrate KNO 3 , is added to the exchange bath, in particular in such a manner that the sum of the sodium and potassium salt contents amounts to 100 wt.-%.

[0074] A third aspect of the present disclosure relates to a glass comprising the following components measured in parts by weight: SiO257 to 69, preferably 59 to 69, particularly preferably 61 to 69, wherein the upper limit is preferably 67, Al2O3 17 to 25, preferably 17 to 24, particularly preferably 17 to 21, B2O30 to 7, preferably 0 to 5, particularly preferably 0 to 4.5, Li2O3 to 5.5, preferably 3.5 to 5.5, particularly preferably 3.5 to 5, Na2O 0.8 to 6, preferably 0.8 to 5.5, particularly preferably 0.8 to 4.5, wherein, for the data expressed in % by weight, the sum of the contents of Al2O3 and SiO2 is preferably between at least 75 and a maximum of 92, preferably a maximum of 90, and / or wherein the total content of alkali metal oxides of the glass and / or glass product is preferably at least 4 % by weight and a maximum of 12 % by weight, preferably a maximum of 10 % by weight.

[0075] As described above, the present invention relates to a glass with particularly good prestressability. This particularly good prestressability can be understood, for example, as the property of effectively storing prestress in the glass network and / or the glass's ability to simultaneously achieve good acid resistance and good exchangeability of existing alkali ions, particularly sodium ions. This property of the glass can also be expressed, in particular, as a prestress or at least prestressability of at least 250 MPa / g Na2O relative to the weight ratio of Na2O in the glass product, per 100 g of glass. This prestressability is preferably at most 1500 MPa / g Na2O, particularly preferably at most 1000 MPa / g Na2O, per 100 g of glass.

[0076] Furthermore, the present disclosure also relates to a method for manufacturing a glass product, preferably a glass product according to an embodiment of the present disclosure, the method comprising the following steps: - an optional first ion exchange is carried out in an exchange bath comprising at least 20% and at most 100% by weight of a sodium salt, preferably sodium nitrate NaNO3, at a temperature between a minimum of 380°C and a maximum of 440°C, for a duration of at least 2 hours, preferably at least 4 hours and at most 24 hours, wherein a potassium salt, in particular potassium nitrate, can optionally be added to the exchange bath, in particular in such a way that the sum of the sodium and potassium salt contents amounts to 100%, - and carrying out the ion exchange in an exchange bath comprising between 0 and 10 parts by weight of sodium salt, preferably sodium nitrate NaNO 3 , relative to the total amount of salts, at an exchange bath temperature of at least 380° C. and at most 440° C., for a duration of at least one hour and at most six hours, wherein a potassium salt, particularly preferably potassium nitrate KNO 3 , is added to the exchange bath, in particular in such a manner that the sum of the sodium and potassium salt contents amounts to 100 parts by weight, and optionally including one or more further ion exchange steps.

[0077] As mentioned above, this means that once the sodium and lithium have been ion-exchanged, i.e. in an exchange bath comprising at least 20% and up to 100% by weight of a sodium salt (preferably sodium nitrate NaNO 3 ), this ion exchange is carried out as a first step. However, this step is only optional, i.e. it is not necessarily mandatory.

[0078] However, it is essential that the potassium-sodium ion exchange step is carried out in an exchange bath containing between 0 and 10 wt.-% of sodium salt, preferably sodium nitrate NaNO 3 , relative to the total amount of salts, wherein a potassium salt, particularly preferably potassium nitrate KNO 3 , is added to the exchange bath, in particular in such a manner that the sum of the sodium and potassium salt contents amounts to 100 wt.-%.

[0079] Another aspect relates to a glass product, which is produced or can be produced using the method according to the aforementioned embodiment of the present disclosure, and or includes the glass according to the third aspect of the present disclosure.

[0080] Another aspect of the present disclosure is the use of the glass product according to the embodiment, which is used as a cover panel, especially as a cover panel in an entertainment electronic device, especially for a display device or screen of a computing device, a measuring device, or a television device, especially as a cover panel for a mobile device, especially for at least one device selected from the following group, the group including: a mobile terminal, a mobile digital processing device, especially a mobile phone, a mobile computer, a PDA, a laptop computer, a tablet computer, a wearable device, a portable watch, and a timing device, or as a protective glass window, especially as a protective glass window for a machine, or as a glass window in a high-speed train, or as safety glass, or as a car glass window, or in a diving watch, or in a submarine, or as a cover panel for explosion-proof equipment, especially for those explosion-proof equipment that require the use of glass.

[0081] Example Exemplary compositional ranges for the glasses are given by the following components measured in parts by weight: SiO257 to 69, preferably 59 to 69, particularly preferably 61 to 69, wherein the upper limit is preferably 67, Al2O3 17 to 25, preferably 17 to 24, particularly preferably 17 to 21, B2O30 to 7, preferably 0 to 5, particularly preferably 0 to 4.5, Li2O3 to 5.5, preferably 3.5 to 5.5, particularly preferably 3.5 to 5, Na2O 0.8 to 6, preferably 0.8 to 5.5, particularly preferably 0.8 to 4.5, K2O 0 to 1, preferably 0 to 0.8, particularly preferably 0 to 0.7, MgO 0 to 2, preferably 0 to 1.5, particularly preferably 0 to 1, CaO0 to 4.5, SrO 0 to 2, preferably 0 to 1.5, particularly preferably 0 to 1, ZnO 0 to 3, preferably 0 to 2, particularly preferably 0 to 1.5, P2O50 to 3, preferably 0 to 2, particularly preferably 0 to 1.7, ZrO2 0 to 3, preferably 0 to 2.8, particularly preferably 0-2.5, very particularly preferably 0 to 1, It may further include impurities and / or refining agents and / or coloring components in an amount not exceeding 2% by weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] The present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1a schematic diagram, not drawn to scale, showing a glass article according to embodiments disclosed herein, and Figure 2 Shown are schematic, not-to-scale, cross-sectional views of glass articles according to embodiments disclosed herein. DETAILED DESCRIPTION

[0083] Figure 1 is a schematic, not-to-scale, illustration of a sheet-shaped glass article according to embodiments disclosed herein.

[0084] Figure 2 A schematic cross-sectional view, not drawn to scale, of a glass article 1 according to an embodiment disclosed herein is shown. The glass article 1 has two regions 101 arranged on two major surfaces of the glass article, which are under compressive stress and are also referred to as compressive stress regions. These compressive stress regions 101 also have Figure 2 The dimension "DoL" is schematically illustrated in FIG. For simplicity and clarity of illustration, the compressive stress zones located at the side edges of the main surfaces are not shown in the figure. These compressive stress zones may be provided there and extend perpendicularly to the main surfaces. The DoL of a sheet-like glass article may differ in magnitude on both sides, with such differences generally being within the range of measurement accuracy. Therefore, the DoL of a sheet-like glass article 1 is generally the same on both sides (at least within the range of measurement accuracy).

[0085] The tensile stress region 102 is located between the compressive stress regions 101 .

[0086] Reference Signs List 1. Plate-shaped glass products; 101 compressive stress zone; 102 The internal area of ​​a glass product that is subject to tensile stress.

Claims

1. A chemically toughened or chemically toughenable plate-shaped glass product (1), comprising glass having a composition comprising Al2O3, SiO2, Na2O and preferably Li2O, and having at least one of the following characteristics: - the glass comprises up to 6% by weight of Na2O, preferably up to 5.5% by weight of Na2O, particularly preferably up to 4.5% by weight of Na2O and preferably at least 0.8% by weight of Na2O, and / or - the glass article (1) has a prestress or at least a prestressability CS of at least 250 MPa / g Na2O relative to the weight ratio of Na2O in the glass article for 100 g of glass, wherein the prestressability is preferably at most 1500 MPa / g Na2O, particularly preferably at most 1000 MPa / g Na2O for 100 g of glass.

2. Glass article (1) according to claim 1, wherein the glass comprises at least 57% by weight of SiO2, preferably at least 59% by weight of SiO2, particularly preferably at least 61% by weight of SiO2, and / or wherein the glass comprises at most 69% by weight of SiO2, preferably at most 67% by weight of SiO2.

3. The glass article according to claim 1 , wherein the glass comprises at least 17% by weight of Al 2 O 3 and / or wherein the glass comprises at most 25% by weight of Al 2 O 3 , preferably at most 24% by weight of Al 2 O 3 , particularly preferably at most 21% by weight of Al 2 O 3 .

4. The glass product (1) according to any one of claims 1 to 3, wherein the sum of the contents of SiO2 and Al2O3 is not more than 92 parts by weight, preferably not more than 90 parts by weight, wherein the total content of network formers in the glass and / or the glass product is particularly preferably at most 92 parts by weight, particularly preferably at most 90 parts by weight.

5. Glass product (1) according to any one of claims 1 to 4, wherein the total content of alkali metal oxides of the glass and / or the glass product (1) is preferably at least 4% by weight and at most 12% by weight, preferably at most 10% by weight.

6. Glass article (1) according to any one of claims 1 to 5, wherein the glass and / or the glass article comprises at least 3 wt.-% Li2O, preferably at least 3.5 wt.-% Li2O and / or at most 5.5 wt.-% Li2O, preferably at most 5 wt.-% Li2O.

7. The glass product (1) according to any one of claims 1 to 6, wherein the glass and / or the glass product has a B2O3 content of at most 7 parts by weight, preferably at most 5 parts by weight, particularly preferably at most 4.5 parts by weight.

8. The glass product (1) according to any one of claims 1 to 7, comprising glass, wherein the glass comprises the following components measured in parts by weight: SiO257 to 69, preferably 59 to 69, particularly preferably 61 to 69, wherein the upper limit is preferably 67, Al2O3 17 to 25, preferably 17 to 24, particularly preferably 17 to 21, B2O30 to 7, preferably 0 to 5, particularly preferably 0 to 4.5, Li2O3 to 5.5, preferably 3.5 to 5.5, particularly preferably 3.5 to 5, Na2O 0.8 to 6, preferably 0.8 to 5.5, particularly preferably 0.8 to 4.5, For the data expressed in % by weight, the sum of the contents of Al2O3 and SiO2 is preferably between at least 75 and at most 92, preferably at most 90.

9. Glass article (1) according to any one of claims 1 to 8, having a thickness of at least 0.4 mm and at most 3 mm, wherein the thickness is preferably at least 0.5 mm and / or preferably at most 2.0 mm, preferably at most 1.0 mm.

10. The glass article (1) according to any one of claims 1 to 9, wherein the glass article has an acid resistance determined as half the weight loss per unit area in a test according to or in accordance with DIN 12116 in mg / dm 2 , and the acid resistance is not greater than 15 mg / dm 2 .

11. A chemically toughened plate-shaped glass product (1), in particular according to any one of claims 1 to 10, The glass product can be obtained by a method comprising the following steps: - an optional first ion exchange is carried out in an exchange bath comprising at least 20% and at most 100% by weight of a sodium salt, preferably sodium nitrate NaNO 3 , at a temperature between a minimum of 380° C. and a maximum of 440° C. for a period of at least 2 hours, preferably at least 4 hours and at most 24 hours, wherein a potassium salt, in particular potassium nitrate, can optionally be added to the exchange bath, in particular in such a way that the sum of the sodium and potassium salt contents amounts to 100%, - and carrying out the ion exchange in an exchange bath comprising between 0 and 10 parts by weight of sodium salt, preferably sodium nitrate NaNO 3 , relative to the total amount of salts, at a bath temperature of at least 380° C. and at most 440° C., for a duration of at least one hour and at most 6 hours, wherein a potassium salt, particularly preferably potassium nitrate KNO 3 , is added to the exchange bath, in particular in such a manner that the sum of the sodium and potassium salt contents amounts to 100 parts by weight, - and optionally one or more further ion exchange steps.

12. A glass comprising at least the following components measured in parts by weight: SiO257 to 69, preferably 59 to 69, particularly preferably 61 to 69, wherein the upper limit can be preferably 67, Al2O3 17 to 25, preferably 17 to 24, particularly preferably 17 to 21, B2O30 to 7, preferably 0 to 5, particularly preferably 0 to 4.5, Li2O3 to 5.5, preferably 3.5 to 5.5, particularly preferably 3.5 to 5, Na2O 0.8 to 6, preferably 0.8 to 5.5, particularly preferably 0.8 to 4.5, For the data expressed in % by weight, the sum of the contents of Al2O3 and SiO2 is preferably between at least 75 and at most 92, preferably at most 90.

13. A method for producing a glass product (1), in particular according to any one of claims 1 to 11, comprising the steps of: - an optional first ion exchange is carried out in an exchange bath comprising at least 20% and at most 100% by weight of a sodium salt, preferably sodium nitrate NaNO 3 , at a temperature between a minimum of 380° C. and a maximum of 440° C. for a period of at least 2 hours, preferably at least 4 hours and at most 24 hours, wherein a potassium salt, in particular potassium nitrate, can optionally be added to the exchange bath, in particular in such a way that the sum of the sodium and potassium salt contents amounts to 100%, - and carrying out the ion exchange in an exchange bath comprising between 0 and 10 parts by weight of sodium salt, preferably sodium nitrate NaNO 3 , relative to the total amount of salts, at a bath temperature of at least 380° C. and at most 440° C., for a duration of at least 1 hour and at most 6 hours, wherein a potassium salt, particularly preferably potassium nitrate KNO 3 , is added to the exchange bath, in particular in such a manner that the sum of the sodium and potassium salt contents amounts to 100 parts by weight, - and optionally one or more further ion exchange steps.

14. Use of the glass article (1) according to any one of claims 1 to 11 as a cover panel, in particular as a cover panel in an electronic entertainment device, in particular for a display device, a screen of a computing device, a measuring device, a television device, in particular as a cover panel for a mobile device, in particular for at least one device selected from the following group: Mobile terminals, mobile digital processing devices, in particular mobile phones, mobile computers, PDAs, laptops, tablet computers, wearable devices, portable watches and timing devices, or as protective glass windows, in particular as protective glass windows for machines, or as glass windows in high-speed trains, or as safety glass, or as car glass windows, or in diving watches, or in submarines, or as cover panels for explosion-proof equipment, in particular for those explosion-proof equipment for which the use of glass is mandatory.

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