Chemically temperable or chemically temperable sheet-like glass article and method for production thereof

Abstract

The invention relates to a chemically toughened or chemically temperable sheet-like glass article comprising a glass composition having Al2O3, SiO2, Li2O and B2O3, the glass and / or glass article comprising up to 7 wt.% B2O3, preferably up to 5 wt.% B2O3, particularly preferably up to 4.5 wt.% B2O3.

Description

[0001] This application is a divisional application of patent application 202080056076.X, whose invention name is "Chemically tempered or chemically temperable sheet glass products and their manufacturing methods". Technical Field

[0002] The present invention relates to a sheet-shaped chemically toughened or at least chemically toughenable sheet-shaped glass product and a method for manufacturing the same. In addition, the present disclosure also relates to a glass composition. Background Art

[0003] Sheet-shaped tempered, in particular chemically tempered, especially highly chemically tempered, glass products are used in particular as so-called protective glasses (or covers or cover glasses) for mobile devices such as smartphones or tablets. Compared to cover glasses made of transparent plastic, these protective glasses are particularly scratch-resistant but also heavier.

[0004] Only chemically toughened sheet glass products can be used as protective glass for mobile terminal devices. This is because these glass products are more robust against mechanical wear loads and therefore have the wear resistance required for the application. In the context of the present disclosure, wear resistance is understood to mean the resistance of the finished product (or product, such as a glass product or glass product) to mechanical loads, in particular to abrasion loads, scratch loads or impact loads. Therefore, the term "wear resistance" or simply "strength" in the context of the present disclosure is generally used to refer to the mechanical resistance of the finished product or product. Specific forms of wear resistance or simply strength are, for example, scratch resistance, bending strength, impact strength or preferably hardness, where it has been shown that combinations of these loads are also possible and are particularly relevant in practical applications. For example, these practical loads are impacts on rough surfaces, especially in the installed state.

[0005] In addition to the requirement for good abrasion resistance, sheet glass products must meet other requirements. In particular, the glass they comprise must be easy to manufacture, meaning, for example, it must be capable of a melting process followed by a hot forming process, preferably without devitrification. Chemical resistance, particularly acid resistance, is also crucial. This is particularly true in the context of the fact that, while good resistance in the final product is essential, good toughening properties must also be ensured during the ion exchange process. It has been shown that good toughening properties during the ion exchange process are often associated with low chemical resistance, as the high mobility of alkali metal ions, which facilitates easy ion exchange, often compromises chemical resistance.

[0006] Known chemically temperable glass and / or chemically temperable or chemically tempered glass products and / or methods for producing such products are described in the following documents, i.e., for example, patent family US 2019 / 0016632 A1 having a family member of granted U.S. Patent No. 9,593,42 B2, patent family US 2018 / 0057401 A1 having a family member of granted U.S. Patent No. 10,294,151 B2, patent family US 2018 / 0029932 A1 having a family member of granted U.S. Patent No. 10,259,746 B2, patent family US 2017 / 0166478 A1 having a family member of granted U.S. Patent No. 9,908,811 B2, patent family US 2018 / 0166478 A1 having a family member of granted U.S. Patent No. 9,908,811 B2, patent family US 2018 / 0166478 A1 having a family member of granted U.S. Patent No. 10,239,784 B2 2016 / 0122240 A1, a family member of US patents with granted US patent 10,150,698 B2 2016 / 0122239 A1, a family member of US patents with granted US patent 10,271,442 B2 2017 / 0295657 A1, a family member of US patents with granted US patent 8,312,739 B2 2010 / 0028607 A1, a family member of US patents with granted US patent 9,359,251 B2 2013 / 0224492 A1, a family member of US patents with granted US patent 9,718,727 B2 2016 / 0023944 A1, a family member of US patents with granted US patent 10,227,253 B2 2012 / 0052271A1, US 2015 / 0030840 A1, a family member of which has been granted US patent 10,227,253 B2, US 2014 / 0345325 A1, a family member of which has been granted US patent 9,487,434 B2, US 2016 / 0257605 A1, a family member of which has been granted US patent 9,517,968 B2, US 2015 / 0239776 A1, a family member of which has been granted US patent 9,567,254 B2, US 2015 / 0259244 A1, a family member of which has been granted US patent 9,676,663 B2, US 2017 / 0036952 A1, a family member of which has been granted US patent 10,266,447 B2, US 2018 / 0002223 A1, a family member of which has a U.S. patent issued as US 9,517,968 B2, US 2017 / 0129803 A1, a family member of which has a U.S. patent issued as US 10,266,447 B2, US 2016 / 0102014 A1, a family member of which has a U.S. patent issued as US 9,676,663 B2, US 2015 / 0368153 A1, a family member of which has a U.S. patent issued as US 9,902,648 B2, US 2015 / 0368148 A1, a family member of which has a U.S. patent issued as US 10,118,858 B2, US 2015 / 0239775 A1, a family member of which has a U.S. patent issued as US 1 2016 / 0264452 A1 and issued U.S. Patent No. 9,902,648 B2, Patent Family US 2016 / 102011 A1 and issued U.S. Patent No. 9,593,042 B2, Patent Family WO 2012 / 126394 A1, Patent Family US 2014 / 0308526 A1 and issued U.S. Patent No. 9,540,278 B2, Patent Family US2011 / 0294648 A1 and issued U.S. Patent No. 8,759,238 B2, Patent Family US 2010 / 0035038 A1 and issued U.S. Patent No. 8,075,999 B2, Patent Family US 4,055,703, Patent Family DE 10 2010 009584 A1, issued German Patent DE 10 2010 009 584 B4, U.S. patent application US 2016 / 0347655 A1 with granted U.S. patent US10351471 B2, patent family CN 102690059 A and granted Chinese patent CN102690059 B, patent family US2016 / 0356760 A1 and granted U.S. patent US 10,180,416 B2, patent family WO 2017 / 049028 A1 with family members of granted U.S. patent US 9,897,574 B2, patent family WO2017 / 087742 A1, patent family US 2017 / 0291849 A1 and granted U.S. patent US 10,017,417 B2, patent family US 2017 / 0022093 A1 and granted U.S. patent US 9,701,569 B2, patent family US 2017 / 300088 (A1) and granted US patent US 9,977,470 B2, patent family EP 1 593 658 A1, granted European patent EP 1 593 658 B1, as well as US patent application US 2005 / 0250639 A1 and patent family US 2018 / 0022638 A1, and granted US patent US 10,183,887 B2. Chemically toughened glass can be divided into so-called aluminosilicate glass (also known as AS glass, aluminosilicate glass, or aluminosilicate glass), whose components include, in particular, Al2O3 and SiO2, as well as alkali metal oxides other than lithium oxide Li2O; and lithium-aluminosilicate glass (also known as LAS glass, lithium-aluminosilicate glass, or lithium aluminosilicate glass), which also includes Li2O as a component.

[0007] More literature on the prior art can be found in patent family US 2019 / 0152838 A1, patent family US 2013 / 0122284 A1 and issued US patent US 9,156,724 B2, patent family US 2015 / 0079400 A1 with issued US patent US 9,714,188 B2, patent family US 2015 / 0099124 A1 and issued US patent US9,701,574 B2, patent family WO 2019 / 085422 A1, patent family US 2017 / 0197869 A1 and issued US patent US 10,131,567 B2, patent family US 2015 / 0030840 A1 and issued US patent US 10,227,253 B2, patent family US 2015 / 0140325 A1 and issued U.S. Patent US 10,125,044 B2, patent family US 2015 / 0118497A1 and issued U.S. Patent US 9,822,032 B2, patent family US 2012 / 0135852 A1 and issued U.S. Patent US 8,796,165 B2, patent family US 2015 / 0147575 A1 and issued U.S. Patent US 10,000,410 B2, and in patent family US 2015 / 0376050 A1 and issued U.S. Patent US 9,783,451 B2.

[0008] These glasses are designed to be chemically toughenable. In the context of this disclosure, chemically toughenable glass is understood to mean glass that can be subjected to an ion exchange process. In such a process, alkali metal ions are exchanged in the surface layer of a glass article, such as a glass sheet. This is achieved by creating a compressive stress zone in the surface layer by exchanging ions with a smaller radius for ions with a larger radius. To this end, the glass article is immersed in a so-called ion exchange bath, such as a molten salt, containing ions with a larger ionic radius, in particular potassium and / or sodium ions, so that these ions migrate into the surface layer of the glass article. During this exchange, ions with a smaller ionic radius, in particular sodium and / or lithium ions, are transferred from the surface layer of the glass article into the ion exchange bath.

[0009] A compressive stress zone is thus formed. This can be described by a characteristic value of the compressive stress, also called "compressive stress" or "CS" for short, and by a compressive stress depth, also called "depth of layer" or "DoL" for short. This compressive stress depth DoL is well known to the person skilled in the art and, in the context of the present disclosure, denotes the depth at which the stress curve passes through zero stress. For glasses of the LAS and LABS types, which can undergo a mixed exchange process, a distinction is made between two different depths of layer, namely the potassium DoL, which describes the depth of the potassium-induced compressive stress, and the sodium DoL, which is also sometimes abbreviated as DoCL. The sodium DoL describes the depth of the sodium-induced compressive stress. Alternatively or additionally, this thickness DoL is determined by means of a stress-optical zero-crossing measurement method, for example by means of a measuring device with the trade name FSM-6000 or SLP1000. These measuring methods are based on different physical methods. The measuring device FSM measures the potassium values ​​(K-DoL and CS(0)), the SLP measures the sodium parameters CS(30) and DoCL.

[0010] The FSM-6000 measuring device can also be used to determine the surface compressive stress and the maximum compressive stress CS of sheets or sheet-like glass products for aluminosilicate glasses.

[0011] In the context of this disclosure, unless explicitly stated otherwise, the terms abrasion resistance and strength are largely used synonymously to refer to the resistance of a material or finished product to mechanical attack. In the context of this disclosure, specific strength, such as drop strength or bending strength (flexural tensile strength), is understood to be a subset of the (overall) strength of a material, finished product, or article. In the context of this disclosure, the hardness of a material is also included under the general term abrasion resistance. In the context of this disclosure, hardness is understood to refer to the mechanical resistance of a material or finished product, such as a sheet glass product, to penetration by another object. The hardness value determined for a material or finished product also depends, among other things, on the specific type of hardness test performed. Well-known hardness scales are, for example, the Mohs or Vickers hardness, though the Mohs scale is no longer a commonly used method for determining hardness. Instead, the Knoop hardness is often specified. However, the Mohs and Knoop hardness scales are disadvantageous methods for determining hardness for glass and glass ceramics because they are not suitable for accounting for the microelasticity, particularly high microelasticity, of the material being tested. These methods rely on visual observation of the indentation after indentation and determine the hardness based on this. In contrast, the so-called Martens hardness is determined mathematically from the indentation curve. In the context of the present invention, hardness is also understood in particular to be the so-called Martens hardness.

[0012] It has been shown that isolated studies of abrasion, scratching, and / or impact loads are only inadequately able to describe and simulate the actual loads to which sheet glass articles are subjected. Consequently, loads that actually occur under real conditions, such as abrasion on surfaces with sharp particles or impact loads, such as when a test body is dropped onto a sheet glass article to determine its impact resistance, are only partially comparable, if at all, to the loads that occur when a mounted sheet glass article is dropped onto a surface.

[0013] Generally speaking, when glass or glass products are used as covers (or cover plates) for mobile electronic products, hardness plays an important role. Generally, the higher the hardness of the glass or glass product, the higher the scratch resistance.

[0014] Generally speaking, in order to avoid scratches, there are two ways to increase the surface hardness of the covering, that is, the cover plate: On the one hand, very hard, transparent materials can be used. For example, so-called "sapphire glass" (single crystal made of corundum) is known. These are used, for example, in watch bezels. These materials scratch very rarely and therefore have only a low tendency to scratch. However, these materials can only be processed with great effort and are very brittle. This also means that fractures can occur even with minimal surface damage. In other words, while these very hard materials are scratch-resistant, so that scratches only occur under high loads, they can also quickly lead to material failure due to fractures.

[0015] Another possibility for increasing the scratch resistance of the cover plate is to apply a layer of hard material to it. Typically, this coating has a thickness of less than 2 μm to minimize optical conspicuity and is applied using conventional coating methods, such as sputtering. This procedure has the advantage that it allows the use of cover plates made of or containing glass, such as sheet glass. In other words, this allows the use of easily processable materials for the cover plate, while the coating can improve their scratch resistance, which is relatively low compared to hard materials.

[0016] However, this method has the disadvantage of requiring complex coating steps. Conventional coating processes for applying hard layers are also unsuitable for coating three-dimensional substrates. Applying the coating to the corners and edges of the coated sheet glass product is also impossible. Furthermore, the hardness gradient between the sheet glass product and the coating is very steep. Consequently, delamination of the interface between the two materials often occurs, particularly under thermal or mechanical loads.

[0017] It has now been shown that the plastic or elastic behavior of materials, such as glass, also plays a significant role in scratch resistance. This is because scratches introduce temporary stresses into the material, which are absorbed by the elastic behavior and can be relaxed without damage after unloading. However, if the introduced temporary stresses lead to plastic deformation of the material, they can become permanent stresses, which can lead to a reduction in strength and, in the worst case, fracture upon unloading.

[0018] Therefore, there is a need for improved sheet glass articles for use as cover plates, which have sufficient scratch resistance but at the same time have low brittleness. Summary of the Invention

[0019] Therefore, the object of the present invention is to provide a sheet glass product, in particular a glass product suitable for use as a cover plate, which at least partially solves the problems of the prior art. Other aspects relate to the use of such a glass product, a glass composition and a method for manufacturing the same.

[0020] This object is achieved by the subject matter of the independent claims. Preferred and specific embodiments are the subject matter of the dependent claims, the description and the drawings.

[0021] Thus, according to a first aspect, the present disclosure relates to a chemically toughened, or at least chemically toughenable, sheet-like glass article. The glass article comprises a glass having a composition of Al2O3, SiO2, Li2O, and BO3, wherein the glass and / or glass article comprises up to 7 wt.% BO3, preferably up to 5 wt.% BO3, and particularly preferably up to 4.5 wt.% BO3. In other words, the glass or glass article is a lithium aluminoborosilicate glass (LABS glass) or a lithium aluminoborosilicate glass article, wherein the BO3 content of the glass and / or glass article is limited.

[0022] This design of the glazing is advantageous because it has been shown that using or from such LABS glass it is surprisingly very simple to obtain a glazing which advantageously combines a high surface hardness with a high prestressing force while achieving good mechanical resistance to loads relevant for practical use, such as so-called "sharp impacts".

[0023] This is all the more surprising because it was previously known that a certain B2O3 content might be suitable for increasing the scratch resistance of glass or glass products, but it was also shown that this effect was limited.

[0024] However, it has surprisingly been shown that a smaller increase in scratch resistance leads to an improvement in the usability of the glass article, for example, for use as a cover (or covering). Instead, it has been shown that in the case of LABS glass, particularly also in the tempered state, the mechanical properties, in particular the elastic properties, of the glass or glass article can be significantly improved. The reasons for this are not entirely clear, but the inventors have concluded that these highly advantageous properties of the glass or glass article are due to the B2O3 content in the lithium-aluminum-silicate glass.

[0025] For this purpose, it may be preferred that the glass or glass product has a certain minimum content of B 2 O 3. According to one embodiment, the glass and / or glass product therefore contains at least 0.5 wt. % B 2 O 3, preferably at least 1.0 wt. % B 2 O 3, particularly preferably at least 1.4 wt. % B 2 O 3.

[0026] According to another aspect, the present disclosure relates to a sheet glass product, in particular a sheet glass product as described above, having at least one of the following features: - In a hardness test method based on or in accordance with DIN EN ISO 14577, the glass article has, when indenting with a Vickers indenter, an E* modulus (also called plate modulus) of at most 87 GPa at an indentation depth of 1 µm and / or an E* modulus of at most 80 GPa at an indentation depth of 2 µm and / or an E* modulus of at most 78 GPa at an indentation depth of 3 µm, wherein the lower limit of the E* modulus is preferably at least 72 GPa in each case.

[0027] - In a hardness test method based on or in accordance with DIN EN ISO 14577, the glass article has an elastic component of deformation of at least 58% at an indentation depth of 1 µm when indented with a Vickers indenter.

[0028] E* modulus is the plate modulus. This is defined as: Where: E IT is the intrusion modulus, and v s is the Poisson constant of the sample.

[0029] The following definitions from DIN EN ISO 14577-1 also apply to E* modulus and intrusion modulus E IT . Figure 1 The diagram shows a schematic diagram of the indentation process. Here, a force F acts on the indenter or indenter 3. This force acts in the normal direction to the surface 41 of the test body or sample 4, the hardness of which is to be determined, and is therefore also called the normal force. The penetration depth or penetration depth is determined perpendicular to the surface 41 and is Figure 1 Use h or h p express.

[0030] The hardness test based on or in accordance with DIN EN ISO 14577 is the determination of the so-called Martens hardness. This hardness determination of the glass articles investigated in the context of the present disclosure was carried out as follows: Using a Micro-Combi-Test (MCT) test device from csm, indentations were performed with a Vickers indenter at a normal force between 0.1 N and 5 N. Indentations took place at a relative room humidity between 30% and 50%. The indentation and evaluation were performed in accordance with DIN EN ISO 14577, but it should be noted that DIN EN ISO 14577 pertains to metals and that no corresponding standard exists for testing brittle materials. The Martens hardness was determined analogously or based on the test method described in DIN EN ISO 14577 for metals or ductile materials. To determine the parameters HM (Martens hardness), E* (plate modulus), and η (elastic component), ten indentations were performed for each force level and the average value was calculated.

[0031] A Vickers indenter is an equilateral rhombic pyramid with an opening angle of 136° between the pyramid sides. Intrusion bodies are also described, for example, in DIN EN ISO 6507-2.

[0032] This design of the glazing is very advantageous since, surprisingly, a particularly good scratch resistance can be achieved while simultaneously achieving good resistance of the glazing to so-called sharp impact loads (for example in so-called drop tests).

[0033] The drop test, which is intended to simulate actual application situations, is preferably carried out as follows: A glass plate is fixed to the sample holder and dropped from a cumulative drop height onto a predefined bottom surface. An overview of the overall structure is given in Figure 4 The glass article used in the drop test has a length of 99 mm and a width of 59 mm, as shown in FIG. Figure 5 As shown, the sample model is magnetically fixed to the sample holder. First, the plastic sheet is glued to a metal housing with the help of double-sided adhesive tape. The metal housing has the shape and weight of a holder for a mobile terminal device, such as a smartphone. For example, a plastic sheet with a thickness of between 4.35 mm and 4.6 mm is suitable in this case (see Figure 6The bonding is preferably carried out using a double-sided adhesive tape with a thickness of approximately 100 μm. The sheet of glass to be tested is then bonded to the plastic plate using a double-sided adhesive tape, preferably a double-sided adhesive tape with a thickness of 295 μm, in particular the tesa® brand, product number 05338, so that a distance of 350 to 450 μm is maintained between the upper edge of the housing or holder and the upper edge of the glass. The glass is raised above the housing frame and does not allow direct contact between the glass body and the aluminum housing. The resulting "set" weighs 177.5 g and simulates the installation of the glass in a mobile terminal device. It is a "model" for a real mobile terminal device, in particular a smartphone, which is then dropped onto a surface of DIN A4 size, the so-called impact surface, with the initial velocity in the vertical direction facing downward, so that the direction of fall is zero. The impact surface is created as follows: Sandpaper with the appropriate grit size, for example grit size 60 (#60), is attached to the base plate using double-sided adhesive tape, for example, 100 μm thick. The adhesive tape used is tesa® (10 m / 15 mm), transparent, double-sided, product number 05338. In the context of this disclosure, grit size is defined according to the standards of the Federation of European Abrasive Producers (FEPA), for example, see DIN ISO 6344, in particular DIN ISO 6344-2:2000-04, Abrasives on substrates, Grain size analysis, Part 2: Determination of the particle size distribution for macrograins P 12 to P 220 (ISO 6344-2:1998).

[0034] The base plate must be sturdy and preferably made of aluminum or, alternatively, steel, but can also be constructed as a slate plate and, for example, granite or marble. In the disclosed description, the base plate, which is aluminum, weighs approximately 3 kg. The sandpaper must be completely taped and adhered without bubbles. The impact surface is only suitable for ten drop tests and must be replaced after the tenth drop. The sample, i.e., the resulting set, is inserted into the test apparatus and oriented using a 2D level (circular level) so that the set is horizontally supported, with the sheet glass pointing toward the bottom, i.e., in the direction of the impact surface (see Figure 7). The first drop is performed from a height of 25 cm, followed by drops from a height of 30 cm. If no fracture occurs, the drop height is increased in 10 cm increments until the glass breaks. The fracture height, source, and appearance are recorded. The test is performed on 15 samples and the average value is calculated.

[0035] It can be advantageous to fasten the sheet glass to the plastic sheet in such a way that, in the event of a glass breakage, the sheet glass remains adhered to the film, both to ensure that it can be removed as easily as possible and to allow inspection of the glass. For this purpose, in addition to the adhesive tape used, a self-adhesive film, such as that used for book packaging, can be placed between the plastic sheet and the sheet glass. This film can then be used to remove the broken sheet glass.

[0036] As described above with respect to the prior art, it has been shown to date that substances generally referred to as very "hard", such as Al2O3 (also known as "sapphire" or "sapphire glass"), although having high scratch resistance, are at the same time very brittle, so that they fail rapidly by fracture under practical load conditions, such as in so-called drop tests.

[0037] By means of the design of the glazing according to embodiments, it is now surprisingly possible to achieve a glazing that is highly scratch-resistant and at the same time also performs well in tests simulating real load conditions, such as the aforementioned drop test.

[0038] In the context of the present disclosure, the scratch resistance is preferably determined as follows: The scratch resistance was also tested using the Micro-Combi-Test (MCT) equipment from csm. Figure 2 A schematic diagram of the measuring principle during a scratching process is shown. The scratch test is performed using an indenter 3, which in the context of the present disclosure is designed as a Knoop indenter, wherein the normal force (here referred to as FN) is 4 N. The indenter 3 is moved at a speed of 24 mm / min over a distance of 1 mm, specifically in the direction of arrow 301. At the same time, the Knoop indenter can also be designed to be stationary and the sample 4 to be moved relative to it. In addition to the normal force FN, a tangential force FT acting parallel to the surface 41 also acts on the surface 41 of the sample 4 to be measured. The penetration depth (also called penetration height, see Figure 1 , where h or h pThe scratch test (indicated by the indenter 3) is determined using a sensor 31. The results obtained using this test depend particularly on the material, size, and shape of the indenter 3 and the properties of the sample 4 being tested, for example, the material and / or microstructure of the sample 4. If the sample 4 has a surface layer 401 whose composition and / or other properties deviate from the bulk properties, such as in the form of a coating or layer, for example, resulting from ion exchange, the results obtained using this scratch test may also depend on the thickness, composition, and / or microstructure of the surface layer 401. For this test, 50 scratches 42 are applied adjacent to each other to the sample 4 or its surface 41 at a relative humidity between 30% and 50%. As described above, the indenter 3 is configured as a Knoop indenter. The evaluation is performed by visually assessing the scratches 42 or scratch tracks 42 on the conchoidal projections 43. The number of scratches or scratch tracks 42 with conchoidal projections 43 is recorded. Figure 3a An exemplary illustration of a good sample having no conchoidal protrusions 43 on the scratch track or scratch 42 is shown in FIG. Figure 3b and 3c In each case, a poor sample in the sense of the scratch test is shown with conchoidal projections 43 on the scratch track or scratch 42. Figure 3b In the case of the illustration in , the conchoidal projections are generated only after the relative movement of the indenter 3 with respect to the sample body 4 has begun, which can be recognized by the absence of conchoidal projections 43 on the initial scratch track 42 and the appearance of conchoidal projections 43 only after the relative movement has begun. Figure 3c In the case shown, the conchoidal projections are already produced at the beginning of the relative movement of the indenter 3 relative to the sample body 4, which can be identified by the absence of a single initial scratch track 42, since at the beginning of the relative movement of the indenter 3 relative to the sample body 4 the conchoidal projections 43 to be identified appear in their lateral width, wherein the scratch track 42 then extends.

[0039] In this case, a conchoidal projection is defined as a widening of the scratch track or scratch by at least three times the lateral width of the initial scratch track in the surface 41 and in an extension parallel to the surface 41 and perpendicular to the scratch track, i.e., perpendicular to the direction of arrow 301. If a conchoidal projection is already generated at the beginning of the movement of the indenter or test body 4, a conchoidal projection is understood to be three times the value of the lateral width of the indenter 3 in the plane of the surface 41 of the test body 4 in the state in which it penetrates into the glass.

[0040] A Knoop indenter is a diamond-shaped tip. Indenters (or indenters) are described, for example, in DIN EN ISO 4545.

[0041] Using the glass or glass article according to the embodiment, it is surprisingly possible to achieve a result of 0 (e.g. a glass or glass article with a total measurement value of 25, see Figures 8 to 10 ), i.e., the conchoidal projections appeared without the introduction of scratches or scratch tracks. This is all the more surprising since comparative samples of glass comprising a different composition or glass articles having a different physical behavior upon indentation may have between 30 and 50 scratches with conchoidal projections (e.g., glasses or glass articles that obtained a total measurement of 23 or 24, see Figures 8 to 10 ).

[0042] The inventors have assumed that this very surprisingly good scratch resistance can be achieved by combining suitable tempering parameters, ie in particular also as a result of the tempering introduced into the glass article.

[0043] The present disclosure therefore also relates to a sheet-like glass article, preferably a sheet-like glass article according to an embodiment of the present disclosure, having a prestress preferably obtained by at least one ion exchange, wherein together with the introduction of the prestress, the elastic component η of the deformation increases to a depth of about 3 μm.

[0044] Thus, the specific features of the glass article according to the present disclosure can be seen in particular in the fact that the glass article has specific elastic properties in the region near the surface, in particular up to a depth of about 3 μm, in particular up to about 2 μm, and also in the region near the surface at a depth of about 1 μm. This is because, for example, in a hardness test method based on or in accordance with DIN EN ISO 14577, a particularly high elastic component of at least 58% is shown.

[0045] While glasses that can achieve even higher elastic components are known, they are constructed differently and, in particular, cannot be chemically toughened to the same degree as the preferred glasses or glass articles according to embodiments. The inventors speculate that the particularly favorable properties of the glasses or glass articles according to the present disclosure can be attributed to the unique glass structure in which a certain proportion of B2O3 is present. For example, in contrast to SiO2, B2O3 generally does not form, or at least forms fewer, three-dimensional bonds, but rather tends to form two-dimensional bonded structures, which, for the sake of clarity, can also be compared to the two-dimensional structure of graphite. It is therefore speculated that a certain (albeit small) proportion of B2O3 network formers in the glass or glass article can result in a glass structure in which the borate glass structure promotes at least a sliding effect within the glass network, resulting in increased elasticity observed at least in the region near the surface.

[0046] According to one embodiment of the glass product, the glass and / or glass product comprises at most 3 wt.% PO, preferably at most 2 wt.% PO and particularly preferably at most 1.7 wt.% PO. PO is an optional component of the glass or glass product according to the present disclosure. PO is a glass component that forms a network and can increase the fusibility of the glass. PO can also promote ion exchange, i.e., shorten the process time. The content of the glass or glass product is preferably at least 0.1 wt.%, preferably at least 0.25 wt.%, and particularly preferably at least 0.5 wt.%. However, a too high PO content in the glass or glass product can reduce the chemical stability of the glass or glass product, or can cause segregation by PO. PO can also cause difficulties in manufacturing because the material of the melting equipment may be attacked. Therefore, the phosphate content is preferably limited, and according to the present disclosure, the P2O5 content in the glass or glass article is at most 3 wt.%, preferably at most 2 wt.%, particularly preferably at most 1.7 wt.%.

[0047] Surprisingly, it has also been shown that the combination of the components B2O3 and P2O5, particularly in the aforementioned contents, allows for the particularly advantageous formation of glass articles that are both scratch-resistant and highly tempered. In this case, P2O5 can compensate for the negative effects of B2O3 on the tempering properties. For example, if the B2O3 content is selected such that B2O3 is present in the glass as trigonal crystals, this leads to higher scratch resistance due to the possible presence of sliding surfaces, similar to the structure of graphite. However, if the proportion of alkali metals and alkaline earth metals in the overall system is high enough so that B2O3 also exists in tetragonal crystals, it will bind more strongly to the alkali metals, which are crucial for ion exchange. This makes ion exchange more difficult. In this case, a certain proportion of P2O5 can help, as P2O5 forms chains in the glass and thus potentially provides channels within the glass, which can promote ion exchange overall.

[0048] In order to form a prestress to a depth of up to 3 μm, particularly up to 2 μm, and particularly also up to 1 μm, at least in the region near the surface of the glass article, it is also advantageous if the glass or the glass article contains a certain minimum content of Na2O. Na2O is a network converter and can therefore particularly influence the interchangeability and thus the temperability of the glass article and, accordingly, the prestress that can be achieved or realized in the glass article. According to one embodiment, the glass and / or glass article contains at least 0.8 wt.% Na2O, wherein the glass and / or glass article contains up to 8 wt.% Na2O, preferably up to 7.5 wt.% Na2O, and particularly preferably up to 7 wt.% Na2O. In other words, according to this embodiment, the glass and / or glass article is designed as a glass or glass article containing Na2O. It is advantageous when the glass and / or glass article contains Na2O because, in this case, ion exchange of sodium ions with potassium ions is possible. This can result in a particularly advantageous design of the glass article with respect to the mechanical properties.

[0049] In particular, it has been shown that the interaction of glass components, particularly the component B2O3, with Na2O enables particularly advantageous designs of glass articles. This is because, as a network converter, Na2O also influences the properties of the glass article at its interfaces. As described above, Na2O also enables exchangeability with potassium ions. This means that the region near the surface of the glass article can be designed in such a way that an exchange of sodium for potassium takes place in this region near the surface. It is precisely in this region near the surface that the good, very advantageous elastic properties of the glass article are achieved, which in particular also leads to, or can lead to, the aforementioned very good scratch results of the glass article according to embodiments, which have only a few, and in some cases even no, conchoidal protrusions.

[0050] The good mechanical properties, in particular elastic properties, of the glass articles according to the present disclosure can be advantageously promoted by a certain content of KO in the glass and / or glass article. According to one embodiment, the glass and / or glass article contains up to 1 wt.% KO, preferably up to 0.8 wt.% KO, particularly preferably up to 0.7 wt.% KO, with the glass and / or glass article particularly preferably containing at least 0.1 wt.% KO. To achieve optimal mechanical properties of the glass or glass article, in particular improved abrasion resistance, particularly optimized sharp impact resistance, while also having good initial stress and improved scratch resistance, it can be advantageous if the glass contains a certain amount of KO. In particular, it has been shown that KO can improve ion exchange and thus temperability. This is attributed to the loose glass structure caused by potassium ions. KO also improves the fusibility of the glass. According to the present disclosure, the glass or glass article preferably contains at least 0.1 wt.%, particularly preferably at least 0.2 wt.% KO.

[0051] Li2O is an essential component of the glasses and glass products according to the present disclosure. In particular, due to the lithium oxide content in the glasses and / or glass products according to the present disclosure, not only does the tempered glass exhibit good strength in static strength tests, such as the flexural strength after four-point bending or the strength determined in the double ring test, but it also offers resistance to blunt impact loads, such as the drop ball test, as well as sharp impact loads, i.e., the effects of particles with an angle of less than 100° on the surface of the glass or glass product (which can also be demonstrated in the so-called drop test). The glasses and / or glass products according to the present disclosure are also distinguished by their improved hardness, as can be seen, for example, in the hardness test method for determining the so-called Martens hardness. Lithium oxide is advantageous in this regard because it enables ion exchange for sodium, thereby resulting in a high degree of toughness or prestressing of the glass or glass product. Therefore, the glasses and / or glass products according to the present disclosure contain at least 3 wt.%, preferably at least 3.5 wt.%. However, according to the present disclosure, the Li2O content is subject to limits. For example, if the Li2O content is too high, segregation can occur. Therefore, the glass and glass products contain at most 5.5 wt. % Li2O.

[0052] Advantageously, a certain minimum content of SiO2 in the glass or glass product is required in order to improve the chemical resistance and mechanical properties of the glass or glass product. The latter is attributed to the support provided to the formation of a rigid, stiff basic glass network that hardly relaxes during ion exchange and thus allows for high prestressing forces. However, due to the extremely high melting temperature of pure SiO2, it is not economical to produce a glass with an excessively high SiO2 content during the subsequent melting process for hot forming. In addition, an excessively high SiO2 content can lead to increased brittleness of the glass or glass product, so for these reasons the SiO2 content must be limited.

[0053] Therefore, it is advantageous if the glass or the glass product contains sufficient SiO2 to achieve sufficient toughness or prestressing. According to one embodiment, the glass or glass product therefore contains at least 57 wt.% SiO2, preferably at least 59 wt.% SiO2, and particularly preferably at least 61 wt.% SiO2. However, it is preferred to limit the SiO2 content in the glass or glass product to avoid causing the glass or glass product to be too brittle. According to one embodiment, the glass or glass product preferably contains at most 69 wt.%, preferably at most 67 wt.% SiO2.

[0054] Al2O3 is known to be added to glasses with a sufficiently high alkali content, particularly to alkali-silicate glasses, as a network former. The addition of Al2O3 reduces the amount of oxygen at the separation point, allowing a rigid network to be achieved even with a given content, which facilitates good temperability or the formation of prestress. Furthermore, Al2O3 facilitates ion exchange. In this way, the temperability of alkali-silicate glasses can be improved, allowing particularly highly tempered glass products to be produced from such glasses. Therefore, according to one embodiment, the minimum Al2O3 content in the glass is advantageously 17 wt.%. However, excessively high Al2O3 contents can reduce the chemical resistance, particularly acid resistance, of the resulting glass or glass product, and can also increase the melting temperature. A glass network that is not too rigid, but still flexible or has an elastic component, is also advantageous for producing glass products that exhibit good properties in practical applications, such as high surface hardness and / or good scratch resistance. The Al 2 O 3 content in the glass or glass product is therefore preferably limited according to a further embodiment and is preferably at most 25 wt. %, particularly preferably at most 21 wt. %.

[0055] Preferably, the total content of Al2O3 and SiO2, given in wt.%, is between at least 75 and at most 92, preferably between at least 75 and at most 90, and / or the total content of network formers in the glass does not exceed 92 wt.%, particularly preferably not more than 90 wt.%.

[0056] A content of at least 75 wt.% of the network formers Al2O3 and SiO2 is particularly advantageous because a sufficient amount of glass formers is present in this way. In other words, this ensures that a vitreous material is obtained and the risk of devitrification during the manufacture of the glass or glass product is reduced. On the other hand, the content of the above-mentioned network formers should not be too high, otherwise the resulting glass will no longer be easily meltable. Therefore, the content of Al2O3 and SiO2 is preferably limited and does not exceed 92 wt.%, preferably does not exceed 90 wt.%. Preferably, the total content of network formers in the glass or glass product is preferably no more than 92 wt.%, particularly preferably no more than 90 wt.%.

[0057] According to another embodiment, the glass article has a thickness of at least 0.4 mm and at most 3 mm.

[0058] The thickness of the glass article is preferably at least 0.5 mm.

[0059] The thickness of the glass article is also preferably limited and, according to one embodiment, is at most 2 mm, preferably at most 1 mm.

[0060] Another aspect of the present invention relates to a lithium-aluminum-borosilicate glass comprising the following components in wt. %: 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 21, B2O30.5 to 7, preferably 0.5 to 5, particularly preferably 0.5 to 4.5, wherein the lower limit may preferably be 1.0 wt. % B2O3, particularly preferably at least 1.4 wt. % B2O3, respectively, Li2O3 to 5.5, preferably 3.5 to 5.5, Na2O 0.8 to 8, preferably 0.8 to 7.5, particularly preferably 0.8 to 7, Therein, the sum of the Al2O3 and SiO2 contents expressed in wt.% is preferably between at least 75 and at most 92, preferably between at least 75 and at most 90.

[0061] This glass is advantageous because it is designed to be chemically toughenable, resulting in a chemically toughened glass article with particularly high strength even when a coarse grain size, such as 60 grit, is used in the so-called drop test. At the same time, the aforementioned advantageous surface hardness and / or scratch resistance of the glass article is achieved because the glass is designed such that it exhibits a high elastic component in the surface layer, at least in the event of deformation or indentation. Despite a high content of glass formers, particularly preferably a high content of at least 75 wt.% of the glass formers SiO2 and Al2O3, the glass according to the invention can be melted surprisingly well.

[0062] The advantageous properties of the glass or glass article according to embodiments of the present disclosure can, according to the inventors, be attributed to the fact that the glass of the composition is designed to be temperable within the above-mentioned limitations in such a way that a highly chemically tempered glass article can be obtained, which nonetheless, most surprisingly, is elastically deformable at least to a certain extent when deformed and is therefore less prone to brittle fracture or conchoidal bulging under surface scratch loads than known hard materials such as Al2O3.

[0063] According to one embodiment of the lithium-aluminum-borosilicate glass, this is given by the following composition in wt. %: 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 21, B2O30.5 to 7, preferably 0.5 to 5, particularly preferably 0.5 to 4.5, wherein the lower limit may preferably be 1.0 wt. % B2O3, particularly preferably at least 1.4 wt. % B2O3, respectively, Li2O3 to 5.5, preferably 3.5 to 5.5, Na2O 0.8 to 8, preferably 0.8 to 7.5, particularly preferably 0.8 to 7, 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, ZrO20 to 3, preferably 0-2.7, particularly preferably 0 to 2, Furthermore, it may contain up to 2 wt.% of impurities and / or refining agents and / or coloring components.

[0064] The advantage of ZrO2 is that, given a sufficiently high proportion of alkali metals in the SiO2 network, it becomes embedded as a glass former and helps strengthen the network. In addition to chemical resistance, it also improves mechanical properties. Furthermore, a certain amount of B2O3 stabilizes the ZrO2 in the glass or prevents the formation of ZrO2 crystals.

[0065] In an embodiment, the glass of the glass article may contain ZrO 2 and particularly preferably contain a ZrO 2 content of at least 0.2 wt. % as a lower limit.

[0066] Yet another aspect of the present disclosure relates to a method for manufacturing a glass article according to an embodiment of the present disclosure, the method comprising the steps of: The ion exchange is carried out in an exchange bath comprising between at least 20 wt.% and at most 100 wt.% of a sodium salt, preferably sodium nitrate NaNO , at a temperature of at least 380° C. and at most 440° C. for at least 2 hours, preferably at least 4 hours and at most 24 hours, wherein optionally a potassium salt, in particular potassium nitrate KNO , can be added to the exchange bath, in particular in such a way that the sum of the contents of sodium and potassium salts adds up to 100%, and optionally carrying out a second ion exchange in an exchange bath comprising between 0 wt.% and 10 wt.% of sodium salt, preferably sodium nitrate NaNO 3 , relative to the total amount of salts, at a temperature of the exchange bath of at least 380° C. and at most 440° C. for 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 way that the sum of the contents of sodium and potassium salts adds up to 100 wt.%, and optionally one or more further ion exchange steps.

[0067] According to a further aspect, the present disclosure also relates to a glass product as a cover, in particular as a cover for entertainment electronic devices, in particular for display devices, computer device screens, measuring devices, TV devices, in particular as a cover for mobile devices, in particular for at least one device from the following group, the group comprising: mobile terminal devices, mobile data processing devices, in particular mobile phones, mobile computers, PDAs, laptops, tablets, wearables, portable clocks and time measuring devices; or as protective glass, in particular as protective glass for machines, or as glass sheets for high-speed trains, or as safety glass sheets, or as automotive glass sheets, or in diving watches, or in submarines, or as covers for explosion-proof equipment, in particular for those uses in which the use of glass is mandatory.

[0068] Example As comparative glasses which do not have B2O3 in their composition and do not have the elastic component η value discussed in more detail below, soda-lime glass provided with reference numeral 23 and Li—Al—Si glass provided with reference numeral 24, in particular lithium-aluminum-silicate glass having a Li2O content of 4.6 wt.% to 5.4 wt.%, a Na2O content of 8.1 wt.% to 9.7 wt.% and an Al2O3 content of 16 wt.% to 20 wt.%, are given.

[0069] The glass articles provided with reference numerals 21, 22 and 25 each comprise or consist of a lithium-aluminum-borosilicate glass containing the following components in wt. %: 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 21, B2O30.5 to 7, preferably 0.5 to 5, particularly preferably 0.5 to 4.5, wherein the lower limit may preferably be 1.0 wt. % B2O3, particularly preferably at least 1.4 wt. % B2O3, respectively, Li2O3 to 5.5, preferably 3.5 to 5.5, Na2O 0.8 to 8, preferably 0.8 to 7.5, particularly preferably 0.8 to 7, Therein, the sum of the Al2O3 and SiO2 contents stated in wt.% is preferably between at least 75 and at most 92, preferably between at least 75 and at most 90.

[0070] The glass article provided with reference numeral 21 has a B2O3 content of 3.6 wt.% + / - 0.5 wt.%.

[0071] The glass article provided with reference numeral 22 has a B2O3 content of 3.9 wt.% + / - 0.5 wt.%.

[0072] The glass article provided with reference numeral 25 has a B2O3 content of 2.8 wt.% + / - 0.5 wt.%.

[0073] It is particularly advantageous and surprising that in these glasses 21, 22 and 25 they are tempered according to a suitable tempering method, for example: The ion exchange is carried out in an exchange bath comprising between at least 20 wt.% and at most 100 wt.% of a sodium salt, preferably sodium nitrate NaNO 3 , at a temperature of at least 380° C. and at most 440° C. for at least 2 hours, preferably at least 4 hours, and at most 24 hours, wherein optionally a potassium salt, in particular potassium nitrate KNO 3 , can be added to the exchange bath, in particular in such a way that the sum of the contents of sodium and potassium salts adds up to 100 wt.%, and optionally carrying out a second ion exchange in an exchange bath comprising between 0 wt.% and 10 wt.% of sodium salt, preferably sodium nitrate NaNO 3 , relative to the total amount of salts, at a temperature of the exchange bath of at least 380° C. and at most 440° C. for 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 way that the sum of the contents of sodium and potassium salts adds up to 100 wt.%, and optionally one or more further ion exchange steps.

[0074] The increased elastic component η of the deformation obtained in the hardness test according to the indentation depth up to a depth of approximately 4 μm, as will be referred to below, Figure 10 Described in more detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] The present invention will be further explained below with reference to the accompanying drawings. Figure 1 A schematic diagram of the indentation process is shown; Figure 2 Schematic diagram showing the measurement principle during the scratching process; Figure 3a An exemplary graph showing a "good" result for a scratch test; Figure 3b An exemplary diagram showing a "bad" result of a scratch test, where the conchoidal protrusions can only be identified after the relative movement of the indenter with respect to the sample body has begun; Figure 3c An exemplary diagram of a "bad" result of a scratch test is shown, wherein a conchoidal protrusion is already identified at the beginning of the relative movement of the indenter with respect to the sample body; Figure 4 An overall view of the drop test structure is shown with individual component labels; Figure 5 Shows the sample holder and trigger mechanism of the drop test structure; Figure 6 An aluminum housing and a plastic plate serving as a sample holder and sample model are shown; Figure 7 A sample model oriented with the aid of a 2D level is shown; Figure 8 A graphical representation of the measurement results of hardness tests on different glasses or glass products; Figure 9 The plate modulus E* according to the depth of the indentation of different glasses or glass products is shown; Figure 10 shows the elastic component of deformation during hardness testing as a function of indentation depth for different glasses or glass articles; Figure 11 A schematic and not-to-scale illustration shows a glass article according to one embodiment; and Figure 12 A schematic and not-to-scale cross-sectional view through a glass article according to one embodiment is shown. DETAILED DESCRIPTION

[0076] Figure 8 The Martens hardness (HM) in MPa determined on five different chemically tempered glass products, each having a different glass composition, is shown. Different data points can be assigned to each of the five different glass products, wherein Figure 8 Middle and below Figure 9 and Figure 10 The data points of the first glass product are represented by diamonds, the second glass products are represented by circles, the third glass products are represented by triangles, the fourth glass products are represented by squares, and the fifth glass products are represented by crosses. Figures 8 to 10In the figure, the various measured values, or, if necessary, the connecting lines or data lines between these measured values, are indicated by 21 for the first glass article (diamond), 22 for the second glass article (circle), 23 for the third glass article (triangle), 24 for the fourth glass article (square), and 25 for the fifth glass article (cross). The measured values ​​(or the total measured values) 21, 22, and 25 were obtained for the glass or glass article according to the present disclosure. The measured values ​​or the total measured values ​​or data lines 23 and 24 were obtained for a comparative example. The third comparative example corresponds to conventional soda-lime glass.

[0077] for Figure 8 The Martens hardness measurements shown, based on a comparison of measurements obtained for different glasses or glass products, indicate that the Martens hardness of the first, second, and fifth glass products (corresponding to the measured values ​​or curves 21, 22, and 25) can be as much as 25% higher after appropriate tempering. As mentioned above, this can be even higher, particularly for indentation depths of up to approximately 4 μm, for example. Particularly high Martens hardnesses can be achieved through the interaction of suitable glass compositions and suitable tempering methods.

[0078] The increase in hardness value is related to the increase in elastic modulus or plate modulus E*. Figure 9 In this case, the measured values ​​obtained for the respective glass or glass product and the corresponding connecting lines through the measuring points are given.

[0079] In general, hardness in glass systems is correlated with the elastic modulus. Given a given load, a higher elastic modulus leads to higher local stresses at the crack tip. When scratched with hard materials, a higher elastic modulus results in increased stresses in the material. Ion exchange produces a continuous decrease in hardness and elastic modulus from the surface toward the center. This continuous decrease avoids adjacent interfaces where stress concentrations could occur. Furthermore, prior to hardening by ion exchange, the material can be effectively machined by grinding and polishing.

[0080] The glasses or glass articles according to the present invention, for which measurements or data lines or connection lines 21, 22, and 25 were obtained, surprisingly resulted in a relatively small increase in the measured panel modulus, while exhibiting a similar increase in hardness as the comparative example obtained for measurements or connection lines 23 and 24. The effect was most pronounced for the glass or glass article assigned to measurement 21. This is due to the specific structure of the LABS glass, whose tempering process was optimized in this case.

[0081] Furthermore, the glass or glass product according to the invention (see measurements 21, 22 and 25) surprisingly has a significantly higher elastic component η than the soda-lime glass (measurement 23) and the fourth glass or fourth glass product of the LAS glass family (measurement 24), as can be seen from Figure 10 It can be seen that the glass family has similar values ​​of 21, 22, and 25, which are significantly different from the measured values ​​of 23 and 24 obtained by the comparative example.

[0082] The elastic component is also related to hardness. The combination of hardness, a relatively low elastic modulus or here the plate modulus (E* modulus) and a relatively high elastic component η leads to a significant improvement in the scratch behavior of chemically toughened glazings in the area near the surface.

[0083] Figure 11 is a schematic and not-to-scale illustration of a sheet glass article according to an embodiment of the present disclosure.

[0084] Figure 12 A schematic and not-to-scale cross-sectional view of a glass article 1 according to an embodiment of the present disclosure is shown. The glass article 1 has regions 101 arranged on both main faces of the glass article, which are under compressive stress and are also referred to as compressive stress regions. These compressive stress regions 101 have a Figure 2 The dimension "DoL" is also schematically indicated at 41. It is possible that the DoL differs on both sides of the sheet glass product due to its dimensions, but these differences are generally within the range of measurement accuracy, so that the DoL of the sheet glass product 1 is generally the same on both sides, at least within the range of measurement accuracy.

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

[0086] List of Reference Numerals 1. Glass products 101 102 21, 22, 23, 24, 25 overall measurement values 3 pressure head 31 sensors Movement direction of 3013 4. Samples and test bodies 41 Surface to be tested of the test body or sample 4 42 scratches, scratch tracks 43 shell-like protrusions 401 Surface layer of sample or test body 4 F, F N Force, Normal Force F T Tangential force h,h p Penetration depth / penetration height DoL layer depth, compressive stress depth.

Claims

1. A chemically toughened or chemically toughenable sheet glass product (1), comprising glass having a composition comprising Al2O3, SiO2, Li2O and B2O3, wherein the glass and / or the glass product (1) comprises at most 7 wt.% of B2O3, preferably at most 5 wt.% of B2O3, particularly preferably at most 4.5 wt.% of B2O3.

2. The sheet-like glass product (1) according to claim 1, wherein the glass and / or the glass product (1) comprises at least 0.5 wt. % B2O3, preferably at least 1.0 wt. % B2O3, particularly preferably at least 1.4 wt. % B2O3.

3. In particular, the sheet-like glass product (1) according to any one of claims 1 or 2 has at least one of the following features: - in a hardness test method based on or in accordance with DIN EN ISO 14577, when indentation is produced using a Vickers indenter, the glass article (1) has an E* modulus of at most 87 GPa at an indentation depth of 1 µm, and / or an E* modulus of at most 80 GPa at an indentation depth of 2 µm, and / or an E* modulus of at most 78 GPa at an indentation depth of 3 µm, wherein the lower limit of the E* modulus is preferably at least 72 GPa, respectively, - In a hardness test method based on or in accordance with DIN EN ISO 14577, when an indentation is produced using a Vickers indenter, the glass article (1) preferably has a deformation elastic component of at least 58% at an indentation depth of 1 µm.

4. In particular, the sheet-like glass product (1) according to any one of claims 1 to 3, It has a prestressing force which is preferably obtained by at least one ion exchange, wherein, together with the introduction of the prestressing force, the elastic component η of the deformation increases to a depth of approximately 3 μm.

5. The sheet-like glass product (1) according to any one of claims 1 to 4, wherein the glass and / or the glass product comprises at most 3 wt.% P2O5, preferably at most 2 wt.% P2O5, particularly preferably at most 1.7% wt.% P2O5.

6. The sheet-like glass article (1) according to any one of claims 1 to 5, wherein the glass and / or the glass article (1) contains at least 0.8 wt. % Na2O, wherein the glass and / or the glass article (1) contains at most 8 wt. % Na2O, preferably at most 7.5 wt. % Na2O, particularly preferably at most 7 wt. % Na2O.

7. The sheet-like glass article (1) according to any one of claims 1 to 6, wherein the glass and / or the glass article (1) comprises at most 1 wt.% of K2O, preferably at most 0.8 wt.% of K2O, particularly preferably at most 0.7 wt.% of K2O, preferably at least 0.1 wt.% of K2O, particularly preferably at least 0.2 wt.% of K2O.

8. The sheet-like glass article (1) according to any one of claims 1 to 7, wherein the glass and / or the glass article (1) comprises at least 3 wt.% of Li2O, preferably at least 3.5 wt.% of Li2O, and / or wherein the glass and / or the glass article (1) comprises at most 5.5 wt.% of Li2O.

9. The sheet-like glass product (1) according to any one of claims 1 to 8, wherein the glass and / or the glass product (1) comprises at most 69 wt.% SiO2, preferably at most 67 wt.% SiO2, and / or wherein the glass and / or the glass product (1) comprises at least 57 wt.% SiO2, preferably at least 59 wt.% SiO2 and particularly preferably at least 61 wt.% SiO2.

10. Glass article (1) according to any one of claims 1 to 9, wherein the glass and / or the glass article (1) comprises at most 25 wt.% Al2O3, preferably at most 21 wt.% Al2O3, and / or wherein the glass and / or the glass article (1) comprises at least 17 wt.% Al2O3.

11. Glass article (1) according to any one of claims 1 to 10, wherein the sum of the contents of Al2O3 and SiO2 in the glass and / or glass article (1) is between at least 75 wt.% and at most 92 wt.%, preferably at most 90 wt.%, and / or wherein the total content of network formers in the glass and / or glass article does not exceed 92 wt.%, particularly preferably does not exceed 90 wt.%.

12. The glass article (1) according to any one of claims 1 to 11, wherein the glass article (1) has a thickness of at least 0.4 mm, preferably at least 0.5 mm.

13. The glass article (1) according to any one of claims 1 to 12, wherein the glass article (1) has a thickness of at most 3 mm, preferably at most 2 mm, particularly preferably at most 1 mm.

14. A lithium aluminoborosilicate glass comprising the following components in wt. %: SiO2 57 to 69, preferably 59 to 69, particularly preferably 61 to 69, wherein the upper limit can be 67, B2O3 0.5 to 7, preferably 0.5 to 5, particularly preferably 0.5 to 4.5, wherein the preferred lower limit may be 1.0 wt. % B2O3, particularly preferably at least 1.4 wt. % B2O3, Al2O3 17 to 25, preferably 17 to 21, Li2O 3 to 5.5, preferably 3.5 to 5.5, Na2O 0.8 to 8, preferably 0.8 to 7.5, particularly preferably 0.8 to 7, in, The sum of the Al2O3 and SiO2 contents in wt.% is preferably between at least 75 and at most 92, preferably between at least 75 and at most 90.

15. A method for producing a glass product (1), in particular according to any one of claims 1 to 13, comprising the following steps: - ion exchange in an exchange bath comprising between at least 20 wt.% and at most 100 wt.% of a sodium salt, preferably sodium nitrate NaNO 3 , at a temperature of at least 380° C. and at most 440° C. for at least 2 hours, preferably at least 4 hours and at most 24 hours, wherein optionally a potassium salt, in particular potassium nitrate KNO 3 , may be added to the exchange bath, in particular in such a way that the sum of the contents of sodium and potassium salts adds up to 100 wt.%, and optionally carrying out a second ion exchange in an exchange bath comprising between 0 wt.% and 10 wt.% of sodium salt, preferably sodium nitrate NaNO 3 , based on the total amount of salts, at an exchange bath temperature of at least 380° C. and at most 440° C. for 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 way that the sum of the contents of sodium salt and potassium salt adds up to 100 wt.%, - and optionally one or more further ion exchange steps.

16. Glass article (1) manufactured or manufacturable according to the method of claim 15 and / or comprising the glass according to claim 14.

17. Use of the glass article (1) according to any one of claims 1 to 13 and 16 as a cover plate, in particular as a cover plate for entertainment electronic devices, in particular for display devices, computer device screens, measuring devices, TV devices, In particular as a cover for a mobile device, in particular for at least one device from the following group, the group consisting of: Mobile terminal equipment, mobile data processing equipment, in particular mobile phones, mobile computers, PDAs, laptops, tablet computers, wearable and portable clocks and timing devices; or As protective glass, in particular as protective glass for machines, or As glass for high-speed trains, or As safety glass, or As car glass, or in a diving watch, or In a submarine, or As a cover for explosion-proof equipment, Especially for those situations where the use of glass is mandatory.

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