CN105829257B

CN105829257B - Chemically prestressed glass and glass part produced therefrom

Info

Publication number: CN105829257B
Application number: CN201480069183.0A
Authority: CN
Inventors: U·达尔曼; G·鲁达斯; I·伯格; I·温伯格
Original assignee: Schott AG
Current assignee: Schott AG
Priority date: 2013-12-17
Filing date: 2014-12-10
Publication date: 2020-01-17
Anticipated expiration: 2034-12-10
Also published as: JP6290425B2; WO2015091134A1; JP2016540721A; CN105829257A; DE102013114225B4; DE102013114225A1

Abstract

The invention relates to a chemically prestressed glass with high strength by ion exchange. The glass comprises the following components, measured in Mol-%: SiO 2₂56‑70；Al₂O₃10.5‑16；B₂O₃0‑3；P₂O₅0‑3；Na₂O 10‑15；K₂O 0‑2；MgO 0‑3；ZnO 0‑3；TiO₂0‑2.1；SnO₂0 to 1; f0.001-5; and 0-2%, preferably 0-1% of other ingredients. Molar content of fluorine relative to B₂O₃Is in the range of 0.0003 to 15, preferably 0.0003 to 11, particularly preferably 0.0003 to 10.

Description

Chemically prestressed glass and glass part produced therefrom

Technical Field

The present invention relates generally to methods of making glass. The invention relates in particular to a chemically prestressed high-strength glass by ion exchange, preferably as a cover glass with good scratch properties. Such glass may be used as protective glass (cover) in electronic devices, such as smart phones, tablets, navigation devices, and the like.

Background

Nowadays, smart phones, tablet computers, navigation devices, and the like are generally operated through touch screens.As a protective element for displays and sensors, thin, ion-exchanged (chemically prestressed) glass elements can be used. Chemical pre-stressing of glass by the addition of small alkali metal ions (e.g. Na)⁺) With larger group-like ions (e.g. K)⁺) To be exchanged. Here, a stress profile is introduced into the glass.

Document WO 2009/070237a1 discloses chemically prestressed glass elements which, in addition to a high fracture toughness, should also be scratch-resistant. Such glass pieces have a standard pre-stress profile, i.e., a surface compressive stress CS of at least 600MPa and a depth of stress layer DoL>40 μm. The brittleness B here satisfies B ═ HV/K_ICWherein HV represents Vickers hardness. K_ICAnd B is a material parameter, which can be derived from scratching. However, no specific measurement is disclosed in WO 2009/070237a1, in particular the lack of data on the humidity of the air.

Such chemically pre-stressed glass pieces are disclosed in document US 2010/0009154a1, and have a CS of at least 200MPa and a DoL of at least 50 μm. This profile is produced by exchange treatment in various pre-stressing baths, and the fracture properties of the glass should be influenced in such a way that: the glass will break into smaller large glass pieces. Scratch resistance or scratch strength is not mentioned here, only in view of the properties at impact. This document does not disclose a precise definition of the profile shape, only CS, DoL and central tension of the surface. In one example, a pre-stress profile is shown in which the maximum potassium concentration is not present on the surface. The potassium concentration on the surface corresponds substantially to the value in volume. Whereby the compressive stress profile is not significant.

Chemically prestressed, breakage-and scratch-resistant glass elements are disclosed in document WO 2011/022661a 2. The tendency to form visually noticeable scratches was tested by a test configuration similar to the test of the invention described herein, wherein the force used in WO 2011/022661a2 was selected to be greater than 5N, which is also greater than the force used in the test of the invention (4N). The chemical pre-stressing treatment is carried out with very small minimum values (CS ≧ 400MPa and DoL ≧ 15 μm). Such a pre-stressed profile corresponds to a standard profile.

However, such small prestressing is far from sufficient for the required strength.

The tendency to form cracks which reduce the strength was also tested according to WO 2011/022661a2 by scoring tests with indenters and not by scratching tests with such indenters, as described in document WO 2009/070237a 1.

In document WO 2012/074983a 1a chemically prestressed glass is disclosed which has a different prestress structure than the standard distribution. The two surfaces are provided with compressive stress areas which are respectively connected with a tensile stress area inwards; there is again a compressive stress in the center of the glass. An internal compressive stress region should be avoided to prevent cracks from penetrating the material, which could lead to fracture. Laminates made from different glass pieces are also disclosed.

Document US 2009/142568a1 discloses glass pieces that can be pre-stressed by ion exchange, the mechanical properties of which, in particular hardness, strength and brittleness, are seen as a function of the so-called non-bridging oxygen (NBO). This document teaches that bridging oxygen, as opposed to non-bridging oxygen, builds up a glass network structure and thereby strengthens the structure. The less non-bridging oxygen in the glass, the stronger the glass. However, the glass pieces made according to this teaching also have drawbacks. These disadvantages are that, although the performance requirements of strength are met, the exchange depth is large and thus the treatment time lasts longer. It can be shown that such glasses have a very dense glass network due to the large boron content. The so-called composition mainly contains Li₂And O. This component allows for rapid ion exchange, contributing to a higher elastic modulus. However, it has been shown that Li₂O quickly fouls the salt bath used for the chemical pre-stress treatment, causing the ion exchange capacity in the bath to rapidly fail.

A cutting method for thermally or chemically prestressed glass elements is disclosed in document US8,341,976B 2. Al (Al)₂O₃And B₂O₃The total molar amount of (A) and a network modifier (Netzwerkwandlern) (traditionally Na₂O、K₂O, MgO and CaO) should be greater than 1. Such glass elements also haveA very dense glass network that prevents deep rapid ion exchange.

In document US 2009/197088a1, ion-exchangeable glass elements are disclosed which have a large prestress, a suitable ion-exchange depth and a low liquidus temperature. The scratch resistance of the glass element is not described.

Document US 2008/286548 discloses ion exchangeable glass pieces having higher compressive stresses in the surface. In addition, viscosity is discussed under liquidus temperature conditions. The scratch performance with respect to the glass pieces achieved is unknown.

Disclosure of Invention

The invention provides a novel technical scheme in the field of ion-exchanged prestressed glass, in particular to a glass cover. The object of the invention is, in particular, to provide a glass which, in addition to a high prestress value and a large exchange depth and/or a short exchange time, has strong scratch resistance.

The glass can also be manufactured by float process and other drawing methods, for which further the requirements of crystallization behavior and viscosity profile are met. The properties mentioned should also be such that they do not contain large amounts of Li₂And O is realized under the condition of O. Preferably the glass is Li-free₂O。

The above object is achieved by the measures of the independent claims. Advantageous embodiments and further aspects of the invention are given in the dependent claims.

In addition to the ion exchange aspect, an important emphasis is first placed on the performance of improved wiping behavior. This property is significantly affected by the suitable glass composition. According to the invention, the glass part preferably contains no CaO and no ZrO₂. CaO has been shown to negatively affect ion exchange, while ZrO₂Negatively affecting the melt processing.

Furthermore, the glass parts according to the invention contain no or only traces of B₂O₃And thus ion exchange is not hindered. However, for an effective prestressing construction, the gist of the invention is the introduction of non-bridging oxygens (NBO) by means of fluorine. The right amounts of the components fluorine and boron contribute to simultaneously having a good prestressEffect and scratch performance.

In particular, the invention provides for this purpose a glass and a glass element comprising the following components, measured in Mol-%, of the molar composition of the glass and of the glass element:

in addition, as an additional condition here, the molar content of fluorine relative to B₂O₃Quotient of molar contents (i.e. F/B)₂O₃) In the range of 0.0003 to 15, preferably 0.0003 to 11, more preferably 0.0003 to 10.

Further advantageous additional conditions are in particular also the total content ratio or quotient of the different specific components.

An advantageous additional condition is the sum of all molar proportions of alkali metal and alkaline earth metal oxides. Here, the alkali metal oxide includes oxides of elements Li, Na, K, and the alkaline earth metal oxide includes oxides of elements Mg, Ba, and Ca. The sum of the alkali metal and alkaline earth metal oxides should be greater than 13 Mol-%, preferably greater than 15 Mol-%.

On the other hand, the sum of the alkaline earth metal oxides is preferably 3 Mol-% or less.

Furthermore, it has proven advantageous to set the conditions for NBO formation as B₂O₃And Al₂O₃Or the molar ratio of the sum of (a) to the sum of alkali metal oxide, alkaline earth metal oxide and fluorine, or the ratio is selected to adjust the formation of NBO. In a preferred embodiment, the molar ratio is from 0.42 to 1.5, preferably from 0.5 to 1.1, particularly preferably from 0.5 to 1.

According to another preferred additional condition, in the composition of the glass, component B₂O₃、Al₂O₃And ZrO₂In a molar total content with component Na₂O、K₂Molar ratio of total molar contents of O and MgO (B)₂O₃+Al₂O₃+ZrO₂)/(Na₂O+K₂O + MgO) is 0.95 to 1.55, preferably in the range from 1.0 to 1.5 and particularly preferably in the range from 1.05 to 1.45.

In addition, the glass may contain very small amounts of impurities, which are inevitable due to the choice of raw materials.

Furthermore, it is also possible to have from 0 to 2%, preferably from 0 to 1%, of other components, such as refining agents, chlorides, sulfates, CaO, SrO, BaO. Preferably, however, the glass does not contain CaO as described above. It is also preferred that the glass does not contain ZrO₂. It will be apparent to one of ordinary skill in the art that the term "free" should be understood to mean: due to the choice of the raw and contact materials, it is still possible to include the above-mentioned materials CaO and ZrO₂Inevitable trace amounts of (a).

On the surface of the glass element, the sodium ions are at least partially exchanged for potassium ions, so that a compressive stress region for a chemical pre-stress treatment of the glass element can be produced on the surface.

Drawings

The present invention will be described in detail below with reference to the accompanying drawings and examples. In which is shown:

FIG. 1 shows a chemically pre-stressed glass element in the form of a sheet, which is superimposed with a graph representing the mechanical stress profile in the glass element;

fig. 2 to 7 show cracks and microscopic images of different scratches in the glass surface of the glass piece;

fig. 8 to 10 show schematic cross-sectional views of different embodiments of the plate-shaped glass element.

Detailed Description

The glasses according to the invention of the above-mentioned composition can also have a high prestress value and/or a rapidly applied chemical prestress. According to a further aspect, the invention relates here also to a chemically prestressed glass element of a glass with the above composition, wherein the glass element is chemically prestressed by exchange of sodium and potassium ions at its surface.

In the glass element according to the invention, the compressive stress ("CS" ═ compressive stress ") of the glass surface can be brought about by this prestressing by exchanging sodium ions with potassium ions to a value of at least 700MPa and the exchange depth of alkali metal ions to a value of at least 25 μm. Also, the compressive stress of the glass surface can reach at least 750MPa at an exchange depth of alkali metal ions of at least 30 μm. Furthermore, the compressive stress of the glass surface may also be greater than 800MPa at an alkali metal ion exchange depth of at least 35 μm.

In fig. 1a plate-shaped glass element 1 according to the invention is shown. The glass element made of glass 2 has a surface 3 with two

opposite sides

31, 32. The glass element 1 is chemically prestressed by exchanging sodium ions from the surface 3 up to an exchange depth Δ d. The compressive stress region 5 is built up by this ion exchange and a larger ion exchange of potassium ions present at a higher concentration at the surface. The curves of the compressive stress CS are shown in the diagram in a superimposed manner. From its maximum CS at the surface 3_maxDecreases in the layer of thickness ad and changes to a slight tensile stress in the inner region of the plate-shaped glass element. The layer thickness deltad corresponds approximately to the compressive stress region 5. The thickness d of the glass element 1 is preferably in the range of 0.2-1.1 mm. For such thin glass elements, it is particularly suitable to use chemical prestressing methods to increase the strength.

Of course, smaller compressive stresses and/or exchange depths may be produced as desired.

The glass element according to the invention is thus also characterized by a glass transition temperature T_g>580 deg.C. High T is required to allow the relaxation process in the glass to be below the glass transition temperature due to sufficient stress in the glass_gIs important and particularly advantageous for chemical prestressing.

For use as a glass cover, in particular for electronic displays, it is particularly preferred that the glass element is made in the shape of a plate. Shaping for such glass sheets can be accomplished by float, drawing (up or down), rolling, or overflow fusion processes.

The glass element according to the invention generally has an operating temperature or operating point (viscosity of 10) of 1380 ℃ or less⁴dPas). Thus, for a particular glass, the glass can be melted in a common type of furnace and the hot forming can be carried out byThe above-mentioned thermoforming treatment, float process, drawing (pull-up or pull-down), rolling or overflow fusion process, is easily carried out.

Thus, according to a further aspect, the invention also relates to a method for producing a plate-shaped glass element, wherein a glass according to the invention is produced and the glass is processed into a glass element in the form of a glass plate by means of a hot forming process, wherein the hot forming process comprises float, drawing, rolling or overflow melting.

Preferably, the prestressing is carried out by exchanging the sodium ions contained in the glass with potassium ions from a salt bath. Thus, in a further step of the method, after the hot forming into a glass sheet, an ion exchange is carried out in a salt bath containing potassium ions.

According to one embodiment of the invention, a method for producing a chemically prestressed glass part is provided, wherein a glass part, preferably a plate-shaped glass part, is produced from the glass according to the invention, and the glass part is then stored in a salt bath containing potassium ions at a temperature of at least 300 ℃ for at least 1.5 hours, the sodium ions of the glass on the surface of the glass part being at least partially exchanged with the potassium ions of the salt bath, wherein the exchange depth of the alkali metal ions is at least 25 μm, as a result of which a compressive stress zone having a surface compressive stress of at least 700MPa is produced on the surface of the glass part, and the glass part is chemically prestressed.

For this ion exchange, the temperature of the salt bath is in the range from 380 ℃ to 460 ℃ and the storage time of the glass plates in the salt bath is particularly advantageous in the range from 1 to 10 hours.

However, these parameters mentioned also apply to the prestressing of non-plate-shaped glass elements, such as glass rods.

According to one embodiment of the invention, chemical prestressing is achieved by storage in a salt bath which contains predominantly KNO₃. Optionally, other potassium-containing components, such as K, may also be included in the salt bath₃PO₄、K₂SO₄And KOH. Preference is given to using pure KNO₃And (3) solution. Alternatively, salts containing silver, e.g. containing AgNO, may also be used₃. The diffusion of silver ions in the ion exchange can also impart an antimicrobial effect to the glass part in this way.

The glass according to the invention can be used for single-stage prestressing with high compressive stress and a large penetration depth. Single-stage prestressing is simpler and faster than a multi-stage process in which the glass is stored in different salt baths in succession.

According to one embodiment of the present invention, a glass plate may be used as the glass member of the present invention. Preferably, however, the glass element is reprocessed, in particular, to obtain a predetermined size of the glass sheet. Further, the reprocessing may include introducing holes, recesses or undercuts, for example by drilling or milling. The reprocessing, such as in particular cutting into a predetermined form or milling, drilling, etching, blasting, can be effected by at least one of the steps of cutting, breaking or grinding before being stored in the salt bath. Post-polishing treatment of the surface is also advantageous if the glass piece is formed by float process, in order to remove tin impurities. It is preferable to carry out a reprocessing before the chemical prestressing in order to avoid damage during processing due to residual stress after the prestressing.

The main application of the pre-stressed form of the glass according to the invention is a high-strength, protective glass cover for electronic mobile devices in the consumer field, such as mobile phones, smart phones, tablets, computers with touch-sensitive display screens, navigation devices, monitors, televisions; such glass covers are commonly used as protective glass for electronic devices with or without touch functionality. On account of the good mechanical properties, such glasses can also be used here in harsh environmental conditions, such as displays and terminals for public use and industrial displays, and also household articles.

Such prestressed glasses can also be used as (exterior) glasses for road, railway, water and air traffic, in particular in the case of thicker glass. For this reason, the glass thickness is preferably at least 1.5 mm. The glass pane according to the invention can also be used as a cover for motor vehicle interior compartments and domestic appliances, or as a high-strength safety glass, wherein also thinner glasses with a thickness of less than 1.5 mm can be used here.

The glass part according to the invention can also be used as a headlight cover or headlight cover.

The mechanical properties described also make this glass additionally suitable as a high-strength substrate material. In this case, substrates which are additionally used as substrates for solar cells or photovoltaic panels, and also for magnetic layers (Magnetschicht) of hard disk media, are also conceivable.

Finally, the prestressed glass panes of the invention can also be combined with other layers, in particular as laminates for safety glass. For example, two or more glass pieces of the invention can be superimposed on one another to produce a high strength safety glass.

Preferably, as is also suitable in the application examples described above, a plate-shaped glass element, in particular a glass disc, is produced. It is also contemplated that the invention may be used on other forms of glass, such as lenses.

Furthermore, glass elements are preferred which are essentially colourless components, wherein the total amount of coloured components (in particular 3d transition metals in the form of coloured ions, in particular V, Cr, Mn, Fe, Ni, Co, Cu in any oxidation state) is less than 0.1 Mol%.

Preferably, the composition further comprises the following components:

particularly preferably, the composition further comprises the following components:

several distinctive features of the composition of the invention have been described above. Further aspects of the glass composition and its features, in particular with regard to ensuring good prestress properties and at the same time enhanced scratch resistance, are explained below.

SiO₂Is a glass former and is very stable as regards the networkThe important major components. Furthermore, such stability also has advantages for sufficient chemical resistance of the glass. Too low SiO₂The content results in a tendency of glass to devitrify (Entglasungsneuging). On the other hand, too high SiO₂The content also brings about a higher melting point. Moreover, has high SiO₂The content of glass also has a very dense structure, which is not conducive to ion exchange.

Al₂O₃The scratch performance is improved and at the same time proves to be advantageous for ion exchange. The latter is marked in an impressive manner in alkali aluminosilicate glasses in terms of CS (surface compressive stress) and DoL (depth of layer of stress) values, in comparison with soda-lime glasses (Kalk-Natron Varianten). In terms of ion exchange, alkali aluminosilicate glasses achieve significantly higher values. Al (Al)₂O₃The formation of nonbridging oxygens (NBO) in the glass structure, which are formed in pure silicate glasses as a result of the network structure modifiers, is avoided. In this case, a good balance between a not too high softening point and a low glass devitrification is achieved on the one hand and, on the other hand, good scratch resistance and good ion exchange properties are also achieved by the composition of the glass part according to the invention.

B₂O₃Show a strong advantageous effect on scratch properties and likewise on melting properties. However, it significantly hinders ion exchange and causes a lengthy treatment time. Otherwise, the process temperature at the time of ion exchange will increase. To avoid these phenomena, B₂O₃Is limited to a certain content of<0.5 Mol-%). According to documents US 2009/142568a1 and US8,341,976B2, the absence of non-bridging oxygen (NBO) implies good scratch resistance. This shows that glass with only Bridging Oxygens (BO) will have very good scratch properties. This also means that such glasses are so strong in their structure that ion exchange is very difficult, since the ions must be able to migrate within the material during the exchange. Therefore NBO should be generated again.

According to documents US 2009/142568A1 and US8,341,976B2, Al is faced on the one hand₂O₃And B₂O₃And on the other hand attempts have been made to modify the network structure. However, this results in a disadvantageously higher B₂O₃The amount and the corresponding longer treatment time in ion exchange. In contrast, the invention is based on the feature that B₂O₃And elemental fluorine.

Fluorine in the case of higher contents has an adverse effect on the scratch resistance of the glass and, in addition, on the ion exchange. However, the incorporation of fluorine as a component of the glass is surprisingly advantageous in the case of glasses having a low boron content. If the fluorine content is too small, poor melting properties of the glass mixture result. Further causing unfavorable ion exchange and again deteriorated scratch performance. Here, the invention is intended to achieve fluorine and B₂O₃Is matched with the content of (1), wherein, F/B₂O₃The molar ratio is in the range of 0.0003 to 10.

Alkali metal oxide (Na)₂O、K₂O) and alkaline earth metal oxides (MgO, CaO, SrO, BaO) reduce the scratch resistance. This may be due to the generation of non-bridging oxygens (NBO) in the glass structure. CaO, SrO and BaO and ZnO hinder ion exchange, and therefore are used only in very small amounts.

P₂O₅Facilitating ion exchange. In addition, by adding P₂O₅To reduce B₂O₃The adverse effects of (c). Small amount of P₂O₅There is a positive effect on the resistance to devitrification of the glass, an excessive amount reducing the chemical resistance and increasing the evaporation during melting.

CeO₂And SnO₂Used as a redox refining agent. Too low a value results in very many bubbles in the glass, and too high a value results in melting residues and undesirable color in the glass.

Preferably, the glass should also be free of traditional health-hazardous or environmentally damaging refining agents As₂O₃And Sb₂O₃。

ZrO₂Is favorable for scraping performance and ionThe exchange is neutral. However, the glass should be "ZrO-free₂Except for impurities normally contained in the raw materials. Too high a content leads to a significantly increased tendency of the glass to devitrify during the melting and forming process, which causes significant disturbances in particular in the hot forming of the overflow fusion process.

The following table lists the glass composition and different properties of four examples of the glass pieces of the invention. The characteristics include: coefficient of Thermal Expansion (CTE), glass transition temperature T_gDensity, operating point, or operating temperature (T4), surface Compressive Stress (CS) and depth of exchange (DOL) of the chemically pre-stressed glass piece, and the number of visible defects when 50 scratch tests were performed on the pre-stressed glass. The chemical prestressing is carried out by applying a compressive stress on KNO₃In a salt bath at a temperature of 420 ℃ for 6 hours.

The scratch test was performed at a humidity of about 50%. In the scratch test, the indenter tip (specifically, knoop indenter) traveled 1mm on the surface of the glass piece under a 4N indenter load at a feed speed of 0.4 mm/s.

The glass of example a1, without borate, is a comparative example. In examples A2 and A3, the molar content of fluorine relative to B₂O₃The quotient of the molar contents of (a) is 10.0.

The glass of example a4 shows particularly few scratching. Here, the contents of fluorine and boron are further balanced with each other. According to another aspect of the present invention, the molar content of fluorine relative to B is not limited to the examples and their particular ingredients₂O₃Is in the range of 0.2 to 2.

With reference to fig. 2 to 7, different scratch patterns in the glass surface are explained. To create the damage mode, scratches 9 were made in the glass surface 3 with a diamond indenter with a defined force of 4N and a feed speed of 0.4mm/s, respectively.

Thus, fig. 2-4 illustrate a visually insignificant failure mode.

To this end, fig. 2 shows a schematic cross-sectional view of a damaged area, i.e. a scratch 9, which is scribed by the indenter tip 7. The spatial extent of the score 9 is kept narrow, limited by the path of the tip of the indenter. Furthermore, the depth of the scratches 9 remains less than the typical exchange depth and the depth of the compressive stress region 5.

Fig. 3 additionally shows an image of a top view of such a scratch; fig. 4 shows an image of a cross-sectional view. As can be seen from the imaging scale shown in fig. 4, the visually insignificant scratches 9 typically have a width and depth of less than 30 microns each, wherein the scratches are scribed in the glass of the invention through the tip of the indenter with the above parameters (pressure 4N, feed speed 0.4 mm/s).

Fig. 5 to 7 show a scratch in which a conspicuous shell shape and peeling can be noted, and thus, the scratch is visible and conspicuous. Such scratches can also be produced on the glass of the invention, i.e. travelling on the glass surface with an indenter at a pressure of 4N and a feed speed of 0.4 mm/s; however, such a shape of the scratches occurs significantly less compared to glasses with lower scratch resistance.

Fig. 5 is a schematic cross-sectional view showing the shape of the scratch 9, corresponding to fig. 2; fig. 6 shows an image of a top view of the surface 3; and figure 7 shows an image of a cross-sectional view.

The scratches 9 clearly appear as visible shell shapes 91 in plan view (fig. 6). This shell shape is produced by a transverse crack 92 which is shown in the sectional illustration in fig. 5 and can also be clearly seen in conjunction with the cross section in fig. 7.

The shell shape extends longer along the surface 3 transverse to the longitudinal direction of the score 9 and is therefore visually noticeable. Furthermore, the transverse cracks still extend within the compressive stress region 5, whereby again the strength achieved by chemical prestressing is not significantly reduced.

The visual defects provided in the examples in the table relate to such scratches as shown in fig. 5 to 7. That is, the indenter generally always causes some degree of damage to the glass surface. The scratch test thus also leaves a scratch on the glass in the remaining examples, for example in the remaining 48 examples in example a4 of the above table. Of course, the pattern of the scratches is as shown in fig. 2 to 4, i.e. visible but not obvious.

Furthermore, the images of fig. 3, 4, 6 and 7 are only intended to show typical damage patterns and are not taken of the glass of the present invention.

Fig. 8 to 10 show an embodiment of the glass element 1 according to the invention. In the embodiment shown in fig. 2, additionally, an edge treatment is carried out for cutting into the final shape. Specifically, the edge 11 of the plate-shaped glass member 1 is formed into a C-shaped edge 12 having a rounded form. The C-shaped edge is produced by grinding or milling, preferably before chemical prestressing.

According to another embodiment, one or both

sides

31, 32 of the plate-shaped glass element 1 or of the glass plate are provided with a coating 14. Additionally, the coating 14 may be a hard material coating, a reflective-resistant coating, a fingerprint-resistant coating, an oleophobic coating, a depression, or a conductive coating. The coating may also be a semiconductor coating, for example for use as a solar cell. The coating 14 may be entirely planar or structured. The coating treatment can be carried out either before or after the prestressing.

In the embodiment shown in fig. 9, the edge 11 is maintained such as to be in the state after cutting, here substantially straight.

As another embodiment, the glass member 1 shown in fig. 9 has the concave portion 16 on one side surface 32. The recess 16 may be, for example, milled. The milled grooves can be machined by CNC processing, wherein the maximum crack depth of the micro-cracks in the milled groove region is limited to 30 μm here. Other possibilities are, for example, etching or sandblasting, for structuring the surface of the glass part.

Finally, fig. 10 shows an embodiment in which the glass element 1 is in the shape of a bent glass plate. As another embodiment, the glass plate is provided with openings or holes 18. The opening or hole may be machined by drilling, milling, sandblasting or etching, before prestressing the glass element 1.

It will be appreciated by persons skilled in the art that the present invention is not limited to the embodiments described above. In particular, the individual features of the embodiments can be combined with one another. For example, the edge shape of fig. 8 may also be applied in the examples shown in fig. 9 or fig. 10. The embodiment of fig. 8 may also have recesses 16 and/or openings 18 as in the embodiments of fig. 9 and 10. In addition, the glass sheet may also be curved in one and/or other directions as a whole.

Claims

1. A glass element (1) comprising the following molar composition of the glass (2) of the glass element (1), measured in Mol-%:

and 0-2% of other components,

wherein the molar content of fluorine is relative to B₂O₃In the range of 0.0003 to 15, wherein the glass has at least one of the following characteristics:

the operating point of the glass (2) is at a temperature lower than 1300 ℃, at which point the viscosity number of the glass is 10⁴dPas；

-transition temperature T_gGreater than 580 deg.C.

2. Glass element (1) according to claim 1, characterized in that the content of the other components is 0-1%.

3. Glass element (1) according to claim 1, characterized in that the molar content of fluorine with respect to B₂O₃The ratio of the molar contents of (a) is in the range of 0.0003 to 11.

4. Glass element (1) according to claim 1, characterized in that the molar content of fluorine with respect to B₂O₃Is in the range of 0.2 to 2.

5. Glass piece (1) according to any of claims 1 to 4, characterized in that it is chemically pre-stressed by replacing sodium ions with potassium ions at its surface, wherein the compressive stress in the surface (3) of the glass (2) is at least 700MPa and the exchange depth of alkali metal ions is at least 25 μm.

6. Glass element (1) according to any one of claims 1 to 4, characterized in that the compressive stress in the surface (3) of the glass (2) is at least 750MPa and the exchange depth of alkali metal ions is at least 30 μm.

7. Glass element (1) according to any one of claims 1 to 4, characterized in that the compressive stress in the surface (3) of the glass (2) exceeds 800MPa and the exchange depth of alkali metal ions is at least 35 μm.

8. A chemically pre-stressed glass comprising the following components, measured in Mol-%:

and 0-2% of other ingredients,

-transition temperature T_gGreater than 580 deg.C.

9. Glass according to claim 8, characterised in that the content of other components is 0-1%.

10. Glass according to claim 8, characterised in that the molar content of fluorine with respect to B₂O₃The ratio of the molar contents of (a) is in the range of 0.0003 to 11.

11. Glass according to claim 8, characterised in that the molar content of fluorine with respect to B₂O₃The ratio of the molar contents of (a) is in the range of 0.0003 to 10.

12. Glass according to any of claims 8-11, characterised in that the sum of alkali metal oxide and alkaline earth metal oxide is more than 13 Mol-%.

13. Glass according to any of claims 8-11, characterised in that the sum of alkali metal oxide and alkaline earth metal oxide is more than 15 Mol-%.

14. Glass according to any of claims 8-11, characterised in that the sum of the alkaline earth oxides is at most 3 Mol-%.

15. Glass according to any of claims 8 to 11, characterised in that B is B₂O₃And Al₂O₃The molar ratio of the sum of (a) to the sum of alkali metal oxide, alkaline earth metal oxide and fluorine is 0.42 to 1.5.

16. Glass according to any of claims 8 to 11, characterised in that B is B₂O₃And Al₂O₃The molar ratio of the sum of (a) to the sum of alkali metal oxide, alkaline earth metal oxide and fluorine is 0.5 to 1.1.

17. The glass of any one of claims 8-11, wherein B is₂O₃And Al₂O₃The molar ratio of the sum of (a) to the sum of alkali metal oxide, alkaline earth metal oxide and fluorine is 0.5 to 1.

18. According to any one of claims 8 to 11The glass according to item (B), characterized in that component B₂O₃、Al₂O₃And ZrO₂In a molar total content with component Na₂O、K₂Molar ratio of total molar contents of O and MgO (B)₂O₃+Al₂O₃+ZrO₂)/(Na₂O+K₂O + MgO) is in the range of 0.95 to 1.55.

19. Glass according to any of claims 8 to 11, characterised in that component B is a component B₂O₃、Al₂O₃And ZrO₂In a molar total content with component Na₂O、K₂Molar ratio of total molar contents of O and MgO (B)₂O₃+Al₂O₃+ZrO₂)/(Na₂O+K₂O + MgO) is in the range of 1.0 to 1.5.

20. Glass according to any of claims 8 to 11, characterised in that component B is a component B₂O₃、Al₂O₃And ZrO₂In a molar total content with component Na₂O、K₂Molar ratio of total molar contents of O and MgO (B)₂O₃+Al₂O₃+ZrO₂)/(Na₂O+K₂O + MgO) is in the range of 1.05 to 1.45.

21. A method for manufacturing a glass element (1) in the shape of a sheet, in which method a glass (2) according to any one of claims 8-20 is provided, which glass is processed into the glass element (1) in the form of a glass sheet by means of a hot forming process, wherein the hot forming process comprises a float, drawing, rolling or overflow fusion process.

22. A method according to claim 21, characterized in that the glass piece (1) is stored in a salt bath containing potassium ions at a temperature of at least 300 ℃ for at least 1.5 hours, the sodium ions of the glass piece (1) on its surface being at least partly exchanged by the potassium ions of the salt bath; wherein the alkali metal ions have an exchange depth of at least 25 μm, thereby creating a compressive stress region on the surface of the glass piece, the compressive stress region having a surface compressive stress of at least 700Mpa, thereby chemically pre-stressing the glass piece.

23. The method according to claim 21, characterized in that the glass piece (1) is stored in a salt bath containing potassium ions at a temperature of 380 ℃ to 460 ℃ for at least 1.5 hours, the sodium ions of the glass piece (1) on its surface being exchanged at least partially by the potassium ions of the salt bath; wherein the alkali metal ions have an exchange depth of at least 25 μm, thereby creating a compressive stress region on the surface of the glass piece, the compressive stress region having a surface compressive stress of at least 700Mpa, thereby chemically pre-stressing the glass piece.

24. Method according to any one of claims 22 to 23, characterized in that the glass article (1) is stored in a salt bath, which mainly contains KNO₃。

25. The method of claim 24, wherein the salt bath can contain other potassium-containing components and/or silver-containing salts.

26. The method of claim 25, wherein the potassium-containing component is component K₃PO₄、K₂SO₄And KOH.

27. A method according to any one of claims 22-23, characterized in that the glass element (1) is further treated by at least one of the steps of cutting, breaking, drilling, milling or grinding before it is stored in the salt bath, after the step of heat-forming treatment.

28. Use of a chemically prestressed glass element (1) according to one of claims 5 to 7 or produced according to one of claims 21 to 27,

use as protective glass for electronic devices with or without touch functionality, mobile phones, smart phones, tablets or computers with touch display screens, monitors, televisions, navigation devices, displays and terminals in public places, industrial displays;

use as high-strength safety glass for surfaces in domestic installations and in road, aviation, railway and water vehicles;

-as glazing for road, rail, waterway and aeronautical vehicles;

-as a headlight cover or headlight cover;

-as a substrate material; or

-laminates for use as safety glass.

29. Use of a chemically prestressed glass part (1) according to one of claims 5 to 7 or produced according to one of claims 21 to 27 as a substrate material for solar cells or hard disks.