JP2017206434A - Asymmetrization method of hydrogen content, manufacturing method of tabular glass article capable of being chemically reinforced at high level, glass article obtained according to the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for asymmetrization of hydrogen content of a tabular glass article capable of being chemically reinforced at high level.SOLUTION: The invention relates to a method for asymmetrization of hydrogen content of a tabular glass article capable of being chemically reinforced at high level. The method includes a step for preparing a tabular departure glass with a shape of belt-like glass or a tabular glass having a first surface and a second surface, and preferably ending the departure glass into an aging device, where the first surface of the tabular glass is contacted with a first gas and the second surface of the tabular glass is contacted with the second gas, a step for adjusting temperature of at least one area, preferably at least one area (B) of the aging device so that at least one area (B) of the belt-like glass or the tabular glass has a temperature of at least T-50 K and a step for adjusting moisture asymmetrization by adjusting water content of at least first gas in the area of the tabular glass having at least T-50 K (B) and at least area thereof contacted with the gas (B). The invention relates to a manufacturing method of a float glass capable of being chemically reinforced at high level. The further aspect of the invention relates to a glass article obtained by the method.SELECTED DRAWING: None

Description

  The present invention relates to a method for asymmetry of the hydrogen content of a highly chemically strengthenable glass article, a method for producing a highly chemically strengthenable plate-like glass article, and a glass article obtained according to the method.

  Chemically hardened aluminosilicate-based glazing has already been used for several years as a cover glass for mobile devices such as laptops or smartphones, especially for display applications, based on the high mechanical strength of this glazing. Has been. In general, the glass used for this has a thickness of less than 1 millimeter. For the production of such glazing, float processes well known to those skilled in the art are often used. However, it is recognized that when the float process is used, the aluminosilicate-based sheet glass has a deflection or warpage, also called warp, due to chemical strengthening.

  This warp is, for example, described in patent documents such as DE 3607404 (DE 3607404C2), because of the asymmetry of the glass manufacturing method, that is, one side of the strip glass is a molten metal, In the float method in which the other surface is in contact with the surrounding environment, which is usually in contact with tin, a strengthening value different from the strengthening value on the so-called non-metal bath side is obtained for the so-called metal bath side during chemical strengthening. Due to being This is due to, for example, the penetration of tin into the lower side of the glass.

  In order to avoid warping after chemical strengthening, German Patent No. 3607404 (DE 3607404C2) includes two methods. For example, the underside of the glass strip, such as the tin bath side, can be scraped off or polished in such a way that the entire thickness of the tin in the glass is removed. In general, it corresponds to a depth of 10 μm to 20 μm and is considered to be correspondingly cumbersome. Furthermore, such mechanical processes are avoided because, in some cases, new surface defects are introduced into the surface.

  On the other hand, in German Patent Registration No. 3607404 (DE 3607404C2), it is at least the lower side of the strip glass or the plate glass, but in some cases, both sides can be treated with sodium ions, for example, by immersing the glass in molten salt. A pretreatment in the form of contact with the source for and / or lithium ions has been proposed. In this way, the sodium content exchangeable at the time of chemical strengthening on the surfaces on both sides of the glass article is compensated, so that uniform strengthening is obtained on both sides and no warpage is caused. Therefore, the effect of German Patent No. 3607404 (DE 3607404C2) is ultimately based on the symmetrization of the surfaces on both sides of the plate glass by the float method.

  Similar symmetrization is described in documents such as DE 102 01 310 4347 A1 (DE10201310347A1). Here, it has been found that the so-called fictive temperatures of the opposite side surfaces of the glass ribbon by the float method can be different from each other. In order to prevent warp, it has been proposed to match the virtual temperature on the upper or non-metal bus side and the virtual temperature on the lower or metal bus side as close as possible to each other by symmetrical cooling. In particular, the fictive temperature difference ΔT should take a value of 7K or less. In this way, warping is avoided because the same reinforcement is achieved.

US Patent Application Publication No. 2015/0072129 (US2015 / 0072129A1) describes the Na ₂ O content on one side compared to the other side in order to achieve the same strengthening on both sides of the glass sheet by the float process. It is proposed to adjust by 0.2 mass%-1.2 mass% low. In this case, the depth of the layer is considered to be up to 5 μm. This is generally achieved by dealkalization, ie by deliberate ion exchange of sodium ions for H ⁺ ions. For example, the ion exchange may be carried out by treatment with HF or the glass surface to be dealkalized, as described in Japanese patent applications such as JP-A-11-171599 (JP-H11 / 171599A1). Can be achieved by contacting with liquid water, under elevated temperature and pressure. The targeted lack of movable sodium on the surface of the glass results in equal proportions of the upper and lower sodium available for ion exchange, so that eventually, both sides are essentially A similar reinforcement is obtained, so that no warping occurs.

According to other documents, for the purpose of symmetrization of the strengthening of the plate glass by the float process, asymmetric temperature treatment (German Patent Application Publication No. 102014205658 (DE1020142658A1)), surface flame treatment (German Patent Application Publication No. No. 1020142357 (DE1020142567A1)) or asymmetric treatment with SO ₂ gas (German Patent Application No. 102014203564 (DE102014420564A1)) has been proposed. Again, each aims to achieve essentially the same strengthening value on both glass surfaces opposite to each other in this way, thus causing no or only a small degree of warpage. It is said.

  Furthermore, US 2014/0079347 (US2014 / 0079347A1) describes a method for adjusting the fluorine concentration on one side to be different from the concentration on the opposite side as intended. Based on the targeted fluorination, dehydration of the thus treated surface of the glass article is reduced, which also affects the strength of chemical strengthening at this surface. In this way, essentially similar strengthening is also achieved on both opposite sides of a glass article, for example a sheet glass.

  US 2014/0102144 A1 is finally a glass by float method, which may be chemically strengthened and between 5 μm and 10 μm as measured from the surface of the glass The difference in hydrogen concentration at the depth takes a value of 0.35 at the most between the upper and lower sides, the hydrogen content on the upper side is lower than the lower side, said concentration being measured by SIMS measurement In addition to the glass, the float glass has a lower hydrogen concentration at a depth of 5 μm to 10 μm on the upper side than the lower side, and a hydrogen content normalized by the silicon content. Disclosed is a glass having a ratio between the upper and lower sides of 1.65 or less. That is, in this glass, that is, the upper hydrogen content is lower than the lower side of the glass, and this difference is adjusted as small as possible. That can be achieved by various measures, which can also be combined, for example using starting materials with less water, reducing the temperature difference between the molten glass and the metal bath Or by adjusting to a moist atmosphere on the upper side of the strip glass in a slow cooling kiln. The symmetrization described here is also based on the idea of producing a glass with a tempering value that is thus well matched on the upper and lower sides.

  All the above-mentioned methods are common in that they are aimed at symmetrization of the tempering to which the tempering process is applied or symmetrization of the sheet glass, Should be achieved by measures. Some of these methods are very time consuming or require the use of hazardous chemicals such as hydrofluoric acid.

  Also, all these methods have considered very specific asymmetry aspects, for example, to move sodium between the metal bus side and the non-metal bus side in different proportions. It needs to be corrected. However, the float glass, in general and depending on the method, exhibits a lot of asymmetry between the upper side and the lower side, for example in the case of the already mentioned tin (in the case where the metal bath is a tin bath). In addition to the different contents, no indication of different contents of alkali metals or different contents of magnesium ions or hydroxide ions is taken into account. Therefore, the symmetrization proposed in the prior art only corresponds to some aspects, which influence the behavior in strengthening and the tendency for warping thereby depending on the glass composition. However, it can be used extensively regardless of the basic glass composition, and there is no simple and powerful way to avoid warping after chemical strengthening.

German registered patent No. 3607404 German Patent Application No. 10201310347 US Patent Application Publication No. 2015/0072129 JP-A-11-171599 German Patent Application Publication No. 10201420658 German Patent Application No. 102014203567 German Patent Application Publication No. 102014203564 US Patent Application Publication No. 2014/0079347 US Patent Application Publication No. 2014/0102144

  The object of the present invention is to provide a method for the asymmetry of the hydrogen content of highly chemically strengthenable sheet glass articles. A further aspect relates to a method of producing a float glass that is highly chemically strengthenable. A still further aspect of the present invention relates to a highly chemically tempered sheet glass article and a chemically strengthened sheet glass article.

Definitions Within the scope of the present invention, a float glass article or float glass plate is a melt that brings one side of a plate-like glass article, i.e. one side of the glass, into contact with a molten metal, i.e. a so-called float bath, during molding. In the law, it refers to a glass article obtained as plate glass, ie in the form of a plate. Within the scope of the present invention, the terms float bath and metal bath are used synonymously.

  Articles formed from glass as contemplated herein exist in the form of plates or strips in which the two spatial dimensions are at least an order of magnitude greater than the third spatial dimension. Since the thickness of the glass articles contemplated herein is up to 4 mm, the length and width are at least in the centimeter range. The band-shaped glass is a plate-shaped glass article obtained continuously, and usually refers to a glass article produced by a glass manufacturing method. Sheet glass is obtained from this strip glass by a subsequent cutting step, where in the case of sheet glass the length and width have the same order of magnitude, but in the case of strip glass the length is clearly greater than its width. large. The length is usually measured in that case parallel to the spatial direction of the glass strip or sheet glass with its greatest horizontal extent, and the width is measured perpendicular to the length. .

  Within the scope of the present invention, the surface of such a glass article that is of particular importance for the occurrence or avoidance of warping is the surface that delimits the article perpendicular to its thickness. The end face that separates the article on the side is less important. Thus, unless otherwise stated explicitly, the surface refers to the upper and lower sides of the glass strip or glass sheet within the scope of the present invention. A further consideration is that the upper side of the glass strip and the upper side of the glass sheet are different from each other only in terms of the size of the surface, and other properties, in particular their chemical properties, are not different from each other. is there. The same applies to the lower side accordingly. Therefore, for example, the explanation relating to the upper side of the strip glass similarly applies to the upper side of the plate glass.

  Float glass refers to an article containing glass that has undergone a float process for molding. In this case, generally, a plurality of glass strips are produced or, after cutting, for example, a plurality of plate glasses. Therefore, in this specification, the term float glass is used synonymously with a glass article formed into a plate shape by the float process.

  Hereinafter, the upper side of the float glass represents the side of the plate-like glass obtained by the float process that has not contacted the liquid metal during molding. In the scope of the present invention, this side is also referred to as the “non-metal bus side”. Often, tin is used as the float bath material, so one example of the non-metal bus side includes the non-tin bus side. The lower side of the float glass correspondingly refers to the side of the plate glass or strip glass in contact with the molten metal in the forming process. Corresponding to the upper side, the lower side is also called the “metal bus side” or “tin bus side” as an example.

  Chemical strengthening refers to the formation of compressive stress in the surface layer of a glass article by performing ion exchange to replace relatively small alkali metal ions, such as sodium ions, with relatively larger alkali metal ions, such as potassium ions. Represents the method. It is generally performed at elevated temperatures in so-called immersion baths.

  In the scope of the present invention, the aging device can be adjusted to a predetermined environmental condition, for example, temperature or atmosphere as desired, and a workpiece placed thereon, for example, a strip glass or a plate glass, is brought into the environmental condition. Refers to a device unit that can be exposed. For example, such an aging device may be configured as a kiln or a climate chamber. In particular, such an aging device is, for example, a slow cooling kiln downstream of a forming unit for the formation of glass strips, where the glass strips are annealed as intended to avoid stress. It may be configured.

  The object is solved by the independent methods of claims 1 and 19 and the plate-like glass article of claim 33. Advantageous embodiments are given in the dependent claims.

Hydrogen content of sheet glass articles that are highly chemically strengthenable, in particular sheet glass articles formed to be chemically strengthenable to a compressive stress CS of a surface of at least 600 MPa and a reinforced layer depth DoL of at least 30 μm. The method for quantity asymmetry is
-Preparing a plate-like starting glass in the form of a strip or sheet glass having a first surface and a second surface opposite to each other, and preferably feeding the starting glass into an aging device; The first surface of the sheet glass is contacted with a first gas, and the second surface of the sheet glass is contacted with a second gas;
At least one region, preferably at least one region (B _A ) of the aging device, wherein at least one region (B _G ) of the glass strip or sheet glass has a temperature of at least T _g −50 K [where the T _g, the steps of adjusting the temperature so as to have a an overall transformation temperature of the glass,
-At least the water content of the first gas in the region (B _G ) of the plate-like glass having a temperature of at least T _g -50K and at least the region (B _W ) where the gas is contacted; A step of adjusting the moisture content of the second gas to be different from the moisture content of the second gas so that moisture asymmetry exists, and after the contact with the at least first gas, the plate-like glass each of the hydrogen content in the at least one region (B _G) of the first surface, and a hydrogen content in at least one region of the second surface of the plate-like glass (B _G), of the ribbon respectively Steps differing to a depth of 5 μm as measured in the direction from the surface of the glass to the center of the glass;
including.

In this case, the hydrogen content in the region (B _G) of the first surface, when the first gas is a wet gas is higher than the hydrogen content in the region (B _G) of the second surface, And when the first gas is a dry gas, it is lower than its hydrogen content on the second surface. Furthermore, the hydrogen content on the surface is the average hydrogen content H 含有 in the layer present at a depth of between 0.5 μm and 5 μm, measured in the direction from the glass surface to the center of the glass, respectively. It is shown. The measurement is preferably performed by ToF-SIMS measurement. Hydrogen content is preferably height normalized to the H of silicon content ^- indicated as the height of the ion signal. Within the scope of the present invention, a first gas is called wet if its absolute water content is higher than that of the second gas, and if its absolute water content is lower than that of the second gas. Is called dry.

  Highly chemically strengthenable means, in the scope of the present invention, that the glass article is formed to be chemically strengthenable, in particular to a surface compressive stress CS of at least 600 MPa and a reinforced layer depth DoL of at least 30 μm. If you are.

The transformation temperature T _g (also called the glass transition temperature) is measured by the intersection of the tangents at the two branches of the expansion curve when measured at a heating rate of 5 K / min. It corresponds to the measurement according to ISO 7884-8 or DIN 52324. In this case, in the scope of the present disclosure, a transformation temperature obtained for the entire glass body, that is, obtained as a macroscopic characteristic of the glass article is referred to as an overall transformation temperature. This overall transformation temperature can optionally be regarded as an average value from the transformation temperature of the surface of the glass article, which differs depending on the interfacial effect, for example, and its transformation temperature in the bulk. Usually, the transformation temperature obtained for the bulk corresponds to the overall transformation temperature based on the fact that the volume of the surface area is only small.

  According to one embodiment of the method, the water content of at least one gas in at least one region of the aging device is measured in a direction perpendicular to the surface of the glass sheet and opposite to the center of the glass. The distance from the surface of the plate-like glass to at least 50 mm is adjusted as defined.

がある。 According to a further embodiment of the method, the following relationship between the wet gas water content W _wet and the dry gas water content W _dry :

There is.

  Where a refers to the correction factor and takes an integer value between 3 and 25, preferably a value of 15.

  According to a further embodiment of the method, the aging device is configured as a kiln or an artificial climate chamber, preferably as a slow cooling kiln.

Advantageously, a relative movement is caused between at least one region (B _A ) of the aging device and the sheet glass, so that the sheet glass has a temperature of at least T _g −50 K (B _G ). And a region (B _W ) in which the water content of at least the first gas in contact with the first surface of the plate-like glass is adjusted as intended is moved throughout the plate-like glass.

  The relative movement is preferably effected by pulling the sheet glass in a thermoforming process, preferably in a float process in which the aging device is configured as a slow cooling kiln.

According to a further embodiment of the invention, the at least one region (B _W ) of the aging device is at least 1 m, preferably at least 3 m, in particular in the longest horizontal extent of the sheet glass. Preferably, it has a horizontal extent in the presence of moisture asymmetry over a section of at least 5 m. Preferably, the aging device is configured as a slow cooling kiln and the longest horizontal extent of the at least one region is parallel to the pulling direction of the sheet glass.

According to a further advantageous embodiment of the invention, the at least one region (B _W ) of the aging device is at least 0.5 m, preferably at least 1 m, parallel to the width of the sheet glass. More particularly preferably, it has a spread of at least 2 m. Most advantageously, the extent of at least one region of the aging device is less than half a meter less than the width of the sheet glass.

Advantageously, the sheet glass is configured as float glass, and in at least one region (B _G ) where the glass article has a temperature of at least T _g −50 K, the at least one gas is a wet gas. Either it is in contact with the upper side or is dry gas and in contact with the lower side.

  According to one embodiment of the method, not only the water content of the first gas, but also the water content of the second gas is adjusted as defined.

  Advantageously, the at least one gas is present as a wet gas, advantageously as a gas with added water vapor. For example, the gas may be present as a gas saturated with water vapor, as a supersaturated gas, or may consist solely of water vapor. Here, the mass flow rate of the gas is at least 30 kg / h, preferably at least 50 kg / h, particularly preferably at least 80 kg / h.

According to a further embodiment of the method, the at least one gas is present as a dry gas. At that time, the flow rate in a aging device of the gas is at least 50 Nm ³ / h (standard cubic meters per hour, i.e. measured under standard conditions), advantageously at least 100 Nm ³ / h. Under standard conditions, in the present invention, it refers to a pressure of 1 atm = 1.01325 bar, and refers to a temperature of 273.15K.

  According to the invention, the gas can be introduced into the surface of the plate-like glass, in particular using a lance. Advantageously, the lance has a plurality of holes through which gas can be ejected.

  Preferably, the plurality of holes in the lance form an angle of 0 ° to 90 °, preferably 45 °, with the aforementioned surface.

  More preferably, the minimum distance between the glass surface and the lance perpendicular to the at least one surface is at least 30 mm, preferably 50 mm.

  According to a further embodiment of the method, water vapor is added to the at least one gas or the gas consists of pure water vapor, where the water vapor is, for example, a boiler and / or a steam heater. Supplied by

  According to another further advantageous embodiment of the invention, the temperature of the at least one gas with moisture adjusted as defined is at least 300 ° C., preferably at least 400 ° C., particularly preferably At least 500 ° C. Most advantageously, the temperature of the gas is 600 ° C.

According to a further advantageous embodiment of the method, the difference in gas pressure in contact with the two opposite surfaces of the sheet glass is perpendicular to the surface from each glass surface. The difference in gas pressure measured as a pressure difference in a region (B _w ) having a defined water content of at least one gas at a distance of 50 mm or less in the direction opposite to the center of the glass ribbon is 500 Pa It is as follows.

  By adjusting the moisture content of the gas in contact with the glass article heated to the lowest temperature, the inventors have adjusted the asymmetry of the hydrogen content in the glass article, in particular the surface of the glass article. It was found that it can be obtained at a depth of up to 5 μm. Certainly, from the prior art, for example from US 2014/0102144 A1 (US 2014/0102144 A1), the basic importance of hydrogen content for avoiding warpage is known, but chemical strengthening. In order to avoid warping, the hydrogen content must be adjusted to the same distribution as possible. On the contrary, however, the inventors surprisingly found that on the one hand no hydrogen content at a depth between 5 μm and 10 μm should be observed, on the other hand the hydrogen content of each glass surface Found that should not be adjusted as equally as possible. Rather, the hydrogen content is intentionally adjusted asymmetrically by the process according to the invention.

［式中、ａは、補正係数を指し、３から２５の間の整数値、有利には１５の値を取る］に相当し、こうしてガスの湿分非対称性が存在する、方法に関する。 The method of asymmetry of the hydrogen content of the plate-like glass article is particularly important when the glass article is obtained by the float process. Accordingly, a further aspect of the present invention is a highly chemically strengthenable glass article, in particular a glass formed to be chemically strengthenable to a compressive stress CS of a surface of at least 600 MPa and a strengthened layer depth DoL of at least 30 μm. In a method for manufacturing an article,
-Continuously feeding the glass melt onto the metal melt;
-Shaping the glass melt in the traction direction into a strip of glass having a predetermined width and thickness, the strip being opposite the metal bath side facing the metal melt and the metal melt Forming a non-metal bus side of the side;
-Cooling the glass strip along the towing section, withdrawing the glass strip from the metal melt and preferably further transferring it into an aging device, for example a slow-cooling kiln;
The moisture content in the at least one region (B _A ) of the traction section, preferably in the aging device, is the water content W on the _upper side of the glass strip indicated by volume% and the lower side of the glass strip The _{lower side} of the water content W of the gas in the following relationship:

Where a refers to a correction factor and corresponds to an integer value between 3 and 25, preferably a value of 15 and thus relates to a method in which there is a moisture asymmetry of the gas.

  According to one embodiment of the present invention, the correction factor a can be 3, 5, 8, 12, 15, 20, and 25. Advantageously, a takes a value of 15.

Therefore, the water content W _{upper side} is always higher than the water content W _{lower side} . This results in an asymmetry of the hydrogen content at the two glass surfaces, in particular in such a way that the upper side of the strip glass has a higher hydrogen content than the lower side.

Advantageously, the temperature of the glass article in the region of the aging device where moisture asymmetry exists is at least T _g -50K.

  The moisture asymmetry of the gas between the upper and lower sides of the glass article, adjusted in at least one region of the traction section by the method, is in the direction perpendicular to each glass surface of the glass and the glass. Exists at an interval of at least 50 mm, measured in the direction opposite to the center.

  At least one region of the traction section is formed according to an embodiment of the method with a moisture asymmetry in the traction direction over a section of at least 1 m, preferably at least 3 m, particularly preferably at least 5 m. Have a horizontal extent.

  According to a further embodiment of the method, the at least one region of the traction section is at least 0.5 m, preferably at least 1 m, particularly preferably at least 2 m, parallel to the width of the glass article. It takes at least a value that has a horizontal extent and is less than half a meter less than the total width of the glass ribbon being pulled.

Particularly advantageously, the temperature of the glass article in the region of the aging device in which moisture asymmetry exists is at least T _g -50K.

According to a further embodiment of the method, the moisture asymmetry is measured by the following measures:
-Introducing a wet gas into the aging device above the ribbon, and / or-introducing a dry gas into the aging device below the ribbon.
Caused by at least one of the following:

  In this case, wet refers to a gas in which the absolute moisture content of a gas is higher than the absolute moisture content of a gas in contact with the opposite side surface of the glass strip, and dry refers to the absolute moisture content of a gas. It refers to the gas when the water content is lower than the absolute water content of the gas in contact with the opposite side surface of the glass strip.

  Advantageously, on the upper side of the glass strip, steam is supplied to the aging device, and the mass flow rate of the steam is at least 30 kg / h, preferably at least 50 kg / h, particularly preferably at least 80 kg / h.

Particularly preferably, the gas flow rate at the bottom of the glass ribbon in the aging device, 50 Nm ³ / h (standard cubic meters per hour) higher than, preferably greater than 100 Nm ³ / h. That is, the gas flow rate is measured under standard conditions.

  According to another further embodiment of the invention, it is measured as the difference in pressure between the upper side of the glass strip and the lower side of the glass strip, each in the region of a distance of 50 mm from the surface of the glass strip. The pressure difference is 500 Pa or less.

By the two methods disclosed within the scope of the present invention, it is possible to create asymmetry of the hydrogen content at the two surfaces of the sheet glass article as described above. Thus, within the scope of the present invention, it is likewise possible to chemically strengthen to a highly chemically strengthenable sheet glass article, in particular to a surface compressive stress CS of at least 600 MPa and a reinforced layer depth DoL of at least 30 μm. A sheet-like glass article formed on the surface of the two glass surfaces with a hydrogen content asymmetry measured from 0.5 μm to 5 μm as measured toward the center of the glass perpendicular to the glass surfaces. A glass article having a configuration in which the average hydrogen content measured is different. In this case, the average hydrogen content is measured by ToF-SIMS measurements and is shown as the signal height of the H ⁻ ion normalized to the height of the silicon signal.

  Advantageously, the plate-like glass article is configured as float glass. In that case, the average hydrogen content in the surface of the glass article formed as an upper side in a float process is higher than the average hydrogen content in the glass surface formed as the lower side.

  That is, the method of the present invention creates an asymmetry in the hydrogen content between the upper and lower sides of the float glass, according to one embodiment. In this regard, a sheet glass produced by the float process has basically two surfaces, which are basically asymmetrically configured, for example its alkali metal content or its mobility. The differences with respect to have already been explained. In addition, it is known that the hydrogen content between the upper side and the lower side of the glass strip obtained by the float process is adjusted to be different (for example, US Patent Application Publication No. 2014/0102144). (See US 2014/0102144 A1). In this case, however, the distribution is exactly the opposite. That is, the hydrogen content on the upper side of the glass strip is lower than that on the lower side of the glass strip (see, for example, paragraph [0084] of US 2014/0102144 A1). about). Also, the measures for hydrogen content equalization proposed in US Patent Application Publication No. 2014/0102144 (US2014 / 0102144A1) merely eases this asymmetry and removes it. If not, it is exactly the opposite.

According to a further embodiment, the average value of hydrogen content on the surface having a higher hydrogen content H, _{wet, 0.5 μm} to 5 μm, from 5 μm from the surface of the glass sheet to the center of the glass. for differences ΔH¯ _wet the hydrogen content _{H¯ 5μm-25μm} to be measured as the average hydrogen content at a depth of 25 [mu] m up to, the following inequality:
ΔH¯ _wet = H¯ _{wet, 0.5μm-5μm -H¯ 5μm-25μm} > 0
Is true.

In this case, advantageously, DerutaH _wet is 0.001 greater than, particularly preferably take 0.0015 larger value.

According to a further embodiment of the invention, the difference ΔH￣ between the average values for the first surface and the second surface takes different values. Advantageously, the mean difference ΔH soot _dry measured on the surface treated with dry gas has a different sign than the mean difference ΔH soot _wet measured on the surface treated with wet gas. , in which, particularly preferably, the average value greater than the difference ΔH¯ _wet is 0.001, and the difference ΔH¯ _dry simultaneously mean value less than -0.001.

According to another further embodiment of the invention, for the quotient Q _ΔH￣ of the mean difference, the following equation:
Q _ΔH￣ = ΔH￣ _{wet type} / ΔH￣ _{dry type}
Is true.

  This quotient preferably has a value of less than −0.005, particularly preferably a value of less than −0.01, and even more preferably a value of less than −0.1.

According to another further embodiment of the invention, the glass article is configured as an aluminosilicate glass. In general, aluminosilicate glass has good chemical strengthenability compared to conventional soda lime glass or low Al ₂ O ₃ borosilicate glass. The composition of such a glass article advantageously has the following composition range (% by weight):
SiO ₂ 40-70
Al ₂ O ₃ 5-20
B ₂ O ₃ 0-10
Na ₂ O 8-20
K ₂ O 0-5
MgO 0-10
CaO 0-2
ZrO ₂ 0-5
Other 0-5
It is.

Particularly preferably, the Al ₂ O ₃ content here is at least 5% by weight, more particularly preferably at least 10% by weight.

  Other components include, for example, fining agents or impurities inevitable in production.

For example, the composition of the plate-shaped glass article is as follows (mass%):
SiO ₂ 61.6
Al ₂ O ₃ 16.8
Na ₂ O 12.1
K ₂ O 4.1
MgO 4.0
ZrO ₂ 1.6
Other 0.9
Indicated by.

  In order to prevent or at least reduce the formation of warps or warpages due to the asymmetry of the hydrogen content at the two surfaces of the glassy glass article, i.e. the differently adjusted hydrogen content of each surface layer. It is not necessary for one surface of the glass article to have a different temperature-time profile during chemical strengthening than the other surface.

  Surprisingly, it has been found that the strengthening values at the two surfaces are different in a sheet glass article reinforced according to an embodiment of the present invention.

The detailed mechanism underlying the phenomenon is not known in this case. However, the inventors postulate that the asymmetry of the hydrogen content at their surfaces results in different glass temperatures _{Tg, surfaces} . The amount of strengthening achieved with a given temperature-time profile will also depend on the glass temperature of each of the glasses, so the presence of such different glass temperatures will also cause differences in strengthening, respectively.

Therefore, according to one embodiment of the present invention, the plate-like glass article is configured such that the transformation temperatures T _{g and surfaces of} both _surfaces are different, and the absolute value | ΔT _{g and surface} | It is formed to be at least between 1K and 10K, preferably at least between 2K and 5K.

For example, in a glass article according to one embodiment of the present invention, T _{g, H +} refers to the transformation temperature of the glass surface having a higher hydrogen content, and T _{g, H −} is a glass having a lower hydrogen content. Refers to the surface transformation temperature, where Tg _{, H +} has a lower value than Tg _{, H-} .

Advantageously, in this case, the plate-like glass article is formed as float glass and the transformation temperature difference Δ (Tg _{, upper side} -Tg _{, lower side} ) between _{the upper side and the lower side} is -1K. Values between -10K and preferably between -2K and -5K, so that Tg _{, upper side} is lower than Tg _{, lower side} .

Unlike the measurement of the bulk glass transformation temperature Tg _{, bulk} , the surface transformation temperature Tg _{, surface} measurement involves special difficulties. The reason for this is that the transformation temperature of the entire glass article including the surface layer, which has different properties depending on the transformation temperature of the bulk, that is, the transformation temperature that the glass has after the depth determined from the surface has a composition different from that of the bulk. This is because there is only a slight difference from temperature. The reason is that the surface layer has only a minor effect on the overall transformation temperature, based on a relatively small volume with respect to the total volume of the glass article considered. Thus, in the scope of the present invention, the transformation temperature The T _g obtained for the entire glass article, only the bulk of the transformation temperature, the namely a transformation temperature obtained after removal of the glass surface resulting from the forming process and annealing process Not bulk transformation temperature Tg, equated with _bulk . These surface layers each reach a depth of up to 5 μm measured starting from the adjacent glass surface.

On the other hand, the measurement of the transformation temperature Tg _{, the surface} , that is, the transformation temperature existing at a depth of up to 5 μm of the glass article becomes more difficult. Within the scope of the present invention, this transformation temperature is measured on glass particles obtained by dry grinding of a plate-like glass article having an average particle size of 10 μm measured as the average diameter of the glass article. Part of this glass grain is then subjected to a process corresponding to the temperature-time-gas treatment of one surface of a plate-like glass article in an aging apparatus, and the other part of the glass grain It is subjected to a process corresponding to the temperature-time-gas treatment of the other surface of the glass article. Subsequently, the transformation temperature is measured in the manner described further above. In this case, within the scope of the present invention, the transformation temperature T _{g of} the glass particles exposed to the wet gas, the surface temperature T _{g of the} glass particles exposed to the wet gas, and the T _{g of the} glass particles exposed to the _wet and dry gases are also within the scope of the invention. _{Therefore, dry method} is measured.

  Furthermore, the treatment of the surface of the glass ribbon with a gas having a different moisture value will certainly change the hydrogen content of each surface, but it will affect the distribution of other elements in the glass. It became clear that it was not affected. That is, the process according to the present method does not change the other asymmetries already obtained from the molding process, for example from the float process.

Therefore, according to one embodiment of the present invention, the content of Na ₂ O in the surface having a higher average hydrogen content (mass%), than the content of Na ₂ O in the surface having a lower average hydrogen content Lower by 0.2 to 0.7 percent.

In particular, the content of Na ₂ O on the upper side of the float glass is lower than its lower side, the mass between the Na ₂ O content on the upper side and the Na ₂ O content on the lower side. The difference Δ (Na ₂ O) in the content of Na ₂ O based on% is between −0.2 mass% and −0.7 mass%.

Further, according to one embodiment, the plate-like glass article is formed as a float glass, wherein Δ (T _{g, upper} -T _{g, lower} ) is between -1K and -10K, Advantageously, it is between −2K and −5K and Δ (Na ₂ O _{upper side—} Na ₂ O _{lower side} ) is between −0.2% by mass and −0.7% by mass.

The plate-like glass article of the present invention is advantageously configured to be highly chemically strengthenable. Particularly advantageously, the sheet-like glass article has a surface compressive stress CS of at least 600 MPa and an enhanced layer depth of at least 30 μm within 4 hours at a temperature of T _g −200 K in KNO ₃ melt. It is configured to be chemically strengthened up to DoL. Accordingly, the present invention is also a chemically strengthened glass article formed into a plate shape, wherein the surface compressive stress CS is at least 600 MPa, and the strengthened layer depth DoL is at least 30 μm. Includes glass articles. CS and DoL can be measured using, for example, a device FSM 6000 manufactured by Luceo.

Accordingly, the present invention, according to one embodiment, is a reinforced sheet glass article, wherein the asymmetry of the hydrogen content at two glass surfaces is directed perpendicular to the glass surface and toward the center of the glass. And a glass article having a configuration in which the average hydrogen content measured at a depth of 0.5 μm to 5 μm is different. In this case, the standardized warp W _s after chemical strengthening is less than 300 μm, preferably less than 200 μm, particularly preferably less than 100 μm. The compressive stress CS at their surface further has a value of at least 600 MPa and the depth of the reinforced layer is at least 30 μm. The compressive stress CS _{H +} at the surface with the higher average hydrogen content also has a lower value than the compressive stress CS _H− at the surface with the lower average hydrogen content.

According to a still further embodiment of the invention, the sheet-like tempered glass article has a lower average hydrogen content with a Na ₂ O content (mass%) at the surface having a higher average hydrogen content. It is constituted so as to be lower by 0.2 to 0.7 percent than the Na ₂ O content in the surface having N.

The standardized warp W _s after chemical strengthening represents the tendency of an unstrengthened sheet glass article to form a warp after chemical strengthening, wherein the standardized warp W _s is defined in advance. Chemical tempering method, predetermined plate glass dimensions having a length l _{0 of} 217 mm and a width b ₀ of 130 mm, a predetermined plate glass thickness D _{0 of} 0.57 mm, and a predetermined warp measurement It is related to the law. For this purpose, the glass article formed into a plate shape having the above-mentioned plate glass dimensions D ₀ , l ₀ and b ₀ is cut but not subjected to further processing, in particular no thin layer removal is performed. I will not. The chemical strengthening is performed in a standardized strengthening method in which the glass article formed into a plate is cured in a potassium nitrate melt at a temperature of T _g -200 K for a period of 4 hours, where the potassium nitrate melt is Previously it has more than 99.9 KNO ₃ . Since the same temperature-time profile is applied to each of the two surfaces, asymmetry in the chemical strengthening of the two surfaces cannot be caused by the strengthening process itself. After this process, the compressive stress CS is typically at least 600 MPa and the depth of the reinforced layer is at least 30 μm.

The warp W for plate-like glass articles having different dimensions obtained by this strengthening process is expressed by the following conversion formula:
(1) W _s = W · (D / D ₀ ) ²
And (2) W _s = W · [(b ² + l ² ) / (b ₀ ² + l ₀ ² )] ^1/2
Can be converted into a standardized warp W _s .

  It should be noted that the glass article formed into a plate may already have a warp prior to strengthening. However, this warp is small and not very serious. Within the scope of the present invention, the warp values shown are basically for chemically strengthened states unless otherwise stated.

  When the plate-like glass article is configured as a strip glass, the strip glass usually has a full width from 2 m to 4 m. Along the end face obtained in the traction direction of the glass ribbon, the glass glass has an ear known to those skilled in the art immediately after the traction process, with the glass having a greater thickness in the so-called quality range. In the ear region, the glass ribbon is usually contacted during the traction process to apply traction. After removing the marginal ears, the strip glass has an effective width of about 1 m to 3.5 m, ie a so-called quality range width, in which the thickness is typically from 0.4 mm. Between 4 mm, preferably between 0.4 mm and 1.5 mm.

The hydrogen content on the glass surface with respect to the sputtering depth is shown. 1 illustrates an exemplary sheet glass article. 1 shows a schematic cross-sectional view through an aging device. 1 shows a schematic cross-sectional view through an aging device.

  The present invention will be further described below with reference to the drawings.

  In FIG. 1, the water content of two surfaces is plotted against the sputtering depth for a sheet-like glass article obtained by the method disclosed herein.

  In this case, the sputtering depth is plotted in μm on the x-axis, and the hydrogen content of the surface measured by ToF-SIMS measurement is plotted on the y-axis, where the hydrogen content Is shown as the hydrogen signal height normalized to the silicon signal height. In this case, curve 1, curve 2 and curve 3 are measurement curves obtained for different glass surfaces.

  Curve 1 is obtained for a surface exposed to a wet gas in the method according to the invention. As can be seen, the hydrogen content at the first 5 μm of this glass surface is higher than for the other two glass surfaces, where the hydrogen content initially shows a maximum value and decreases to a depth of 5 μm. Yes.

  Curve 2 represents the surface on the opposite side of a sheet glass article exposed to dry gas. Here, the hydrogen content is lower than curve 1 in the first 5 μm, but the hydrogen content continues to increase. Curves 1 and 2 intersect at a depth of about 5 μm. From a depth of 20 μm onwards, the two hydrogen contents of the first “wet” surface and the second “dry” surface approach each other. For example, the first curve is understood as the measured value on the upper side of the float glass plate and the curve 2 is understood as the measured value on the lower side of the float glass plate, with the upper side being treated with wet gas. The lower side is treated with a dry gas relative to it.

  In contrast, curve 3 shows a typical evolution of the hydrogen content on the upper side of a float glass that has not been exposed to a wet atmosphere according to the method disclosed herein. As is apparent, the hydrogen content of the surface here is lower than the hydrogen content of the surface treated by the present method on which the measurement of curve 1 is based, to a depth of at least 18 μm. Furthermore, the hydrogen content on the upper and lower sides becomes equal only after a depth of at least 25 μm. For a typical float glass for the first time after a depth of 25 μm, ie not treated by the present method, it can be assumed that there is a bulk water content.

  FIG. 2 schematically and exemplarily shows a highly chemically strengthenable sheet glass article according to the invention. In this case, the glass article is formed in a plate shape in the sense that the thickness D is at least an order of magnitude smaller than its length l and its width b. The length l is the longest horizontal spread of the plate-like glass article. Vertically, the width b of the plate-like glass article is shown.

FIG. 3 shows a cross section through the aging device (6) schematically and not faithfully to scale. The aging device is here formed as a slow cooling kiln as an example, and here, the plate-shaped glass article (4) is formed here as a strip glass as an example, and a roller ( 5) is moved. In this case, in the aging apparatus, the temperature of the glass article is adjusted in the region B _A , and by the temperature adjustment, the glass article has at least T _g −50 K in the region B _G of the plate-like glass article (4). It is comprised in the form which will have temperature.

Furthermore, the aging device has a gas space (61) in which the first gas is present and a gas space (62) in which the second gas is present, wherein these two gas spaces are strictly connected to each other. They do not exist in isolation, that is, they are not hermetically sealed to one another. In the gas space (61), there is a first gas having an adjusted water content at least in the partial region B _W1 . Furthermore, in the gas space (62), a second gas having a similarly adjusted water content is present at least in the region B _W2 , where the water content of the first gas and the second gas is relative to each other. Due to the difference, one gas exists as a dry gas and the other gas exists as a wet gas.

As an example, in FIG. 3, here, only the upper side (43) of the glass article represents a first gas having a water content adjusted as defined in the region B _W1 , where It is assumed that the water content in the region B _W1 is adjusted to the wet state as intended. In contrast, region B _W2 is not shown for clarity.

FIG. 4 shows, by way of example, a section of the aging device (6) parallel to the cutting plane AA ′ of FIG. 3, ie perpendicular to the pulling direction. The cut surface is not only in the area B _{A of the} aging device, but also in the area B _W1 of the gas space (61) and the area B _G of the glass article (4). The glass article (4) has a total width b _B , which is the width of the glass article (4) including the ears (41) to be separated later. Furthermore, the width b _Q of the quality range 42 is shown. The glass article (4) rests on the roller (5) at least in a partial area.

DESCRIPTION OF SYMBOLS 1 Hydrogen content in upper side of wet processing of float glass, 2 Hydrogen content in lower side of float glass, 3 Reference value of hydrogen content in upper side of float glass, 4 Glass article, 41 Ear part of glass article 42 glass article quality range, 43 upper side of glass article, 5 rollers, 6 aging device, 61 gas space with first gas in aging device, 62 gas space with second gas in aging device, D The thickness of the glass article, l the length of the glass article, b the width of the glass article, B _W1 the area with the first water content, B _W2 the area with the second water content, B _A the area of the aging device, B _G Gas area, b _Q quality range width, b _B glass article total width

Claims (46)

Hydrogen content of sheet glass articles that are highly chemically strengthenable, in particular sheet glass articles formed to be chemically strengthenable to a compressive stress CS of a surface of at least 600 MPa and a reinforced layer depth DoL of at least 30 μm. In a method for quantity asymmetry,
-Preparing a plate-like starting glass in the form of a strip or sheet glass having a first surface and a second surface opposite to each other, and preferably feeding the starting glass into an aging device; The first surface of the sheet glass is contacted with a first gas, and the second surface of the sheet glass is contacted with a second gas;
At least one region, preferably at least one region (B _A ) of the aging device, wherein at least one region (B _G ) of the glass strip or sheet glass has a temperature of at least T _g −50 K [where the T _g, the steps of adjusting the temperature so as to have a an overall transformation temperature of the glass,
-At least the water content of the first gas in the region (B _G ) of the plate-like glass having a temperature of at least T _g -50K and at least the region (B _W ) where the gas is contacted; A step of adjusting the moisture content of the second gas to be different from the moisture content of the second gas so that moisture asymmetry exists, and after the contact with the at least first gas, the plate-like glass each of the hydrogen content in the at least one region (B _G) of the first surface, and a hydrogen content in at least one region of the second surface of the plate-like glass (B _G), of the ribbon respectively Steps differing to a depth of 5 μm as measured in the direction from the surface of the glass to the center of the glass;
Wherein the hydrogen content in the region (B _G) of the first surface, when the first gas is a wet gas is higher than the hydrogen content in the region (B _G) of the second surface, and When the first gas is a dry gas, the hydrogen content at the second surface is lower and the hydrogen content at those surfaces is measured in the direction from each glass surface to the center of the glass, respectively. The average hydrogen content H￣ in the layer present at a depth between 0.5 μm and 5 μm, where the measurement is preferably made by ToF-SIMS measurement and the hydrogen content is preferably, the height is normalized to the H of silicon content ^- shown as the height of the ion signal, and the first gas, if the absolute water content is higher than that of the second gas Is called wet and its absolute water content is second Called dry when scan lower than, said method. The method according to claim 1, wherein the water content of at least one gas in at least one region (B _W ) of the aging device is opposite to the center of the glass in a direction perpendicular to the surface of the sheet glass. A method that is adjusted as defined from the surface of the sheet glass to a distance of at least 50 mm as measured in the direction. The method according to claim 1 or 2, wherein the following relationship between the _wet water content W _wet and the dry gas water content W _dry , each expressed in volume%:

Where a refers to a correction factor and takes an integer value between 3 and 25, preferably a value of 15.   4. A method according to any one of claims 1 to 3, wherein the aging device is configured as a kiln or a climate chamber, preferably as a slow cooling kiln. 5. A method according to any one of claims 1 to 4, wherein a relative movement is caused between at least one region (B _A ) of the aging device and the plate-like glass, and thus plate-like. A region (B _G ) in which the glass has a temperature of at least T _g −50K, and a region in which the water content of at least the first gas in contact with the first surface of the plate-like glass is adjusted as intended ( _BW ) is moved through the glass sheet.   6. The method according to claim 5, wherein the relative movement is performed by pulling the plate-like glass in the thermoforming method, preferably in the float method, and the aging device is configured as a slow cooling kiln. Is that way. The method according to any one of claims 1 to 6, wherein at least one region (B _W ) of the aging device is at least 1 m in the longest horizontal spreading direction of the sheet glass. Preferably it has a horizontal extent in the presence of moisture asymmetry over a section of at least 3 m, particularly preferably at least 5 m, wherein the aging device is preferably configured as a slow-cooling kiln And the longest horizontal spread is parallel to the pulling direction of the sheet glass. 8. The method according to claim 1, wherein at least one region (B _W ) of the aging device is at least 0.5 m parallel to the width of the glass sheet. A process which preferably has a spread of at least 1 m, more particularly preferably of at least 2 m, wherein a spread which is less than half a meter less than the width of the sheet glass is most advantageous. A method according to any one of claims 1 to 8, at least one region a plate-shaped glass is constructed as a float glass, and the glass article having a temperature of at least T _g -50K ( In B _G ), the at least one gas is either a wet gas and is in contact with the upper side, or is a dry gas and is in contact with the lower side.   The method according to any one of claims 1 to 9, wherein not only the water content of the first gas but also the water content of the second gas is adjusted as defined.   11. A method according to any one of claims 1 to 10, wherein at least one gas is present as a wet gas, i.e. saturated or supersaturated with water vapor, for example as a gas to which water vapor has been added. Present as a pure gas or consisting only of water vapor and the gas mass flow rate is at least 30 kg / h, preferably at least 50 kg / h, particularly preferably at least 80 kg / h. 11. A method according to any one of the preceding claims, wherein at least one gas is present as a dry gas and the flow rate of the gas in the aging device is at least 50 Nm < ³ > / h (1 Standard cubic meters per hour), preferably at least 100 Nm ³ / h.   13. A method according to any one of claims 1 to 12, wherein at least one gas is introduced into the surface of the sheet glass by means of a lance, wherein the lance is advantageously passed through. A method having a plurality of holes through which gas can be spouted.   14. The method according to claim 13, wherein the plurality of holes in the lance form an angle between 0 and 90 degrees, preferably 45 degrees, with said surface.   15. A method according to claim 13 or 14, wherein the minimum distance between the glass surface and the lance perpendicular to the at least one surface is at least 30 mm, preferably 50 mm.   16. The method according to any one of claims 1 to 15, wherein water vapor is added to the at least one gas or the gas consists of pure water vapor, where the water vapor is A method, eg supplied by a boiler and / or steam heater.   17. A method as claimed in any one of claims 1 to 16, wherein the temperature of the at least one gas having moisture adjusted as defined is at least 300 ° C, preferably at least 400 ° C, in particular A process which is preferably at least 500 ° C, most preferably 600 ° C. 18. The method according to any one of claims 1 to 17, wherein a difference between gas pressures in contact with two surfaces on opposite sides of a plate-like glass, the surfaces from each glass surface. Measured as a pressure difference present in a region (B _w ) having a defined water content of at least one gas at a distance perpendicular to the center of the glass strip and not more than 50 mm away from the center of the glass strip The pressure difference is 500 Pa or less. Highly chemically tempered sheet glass articles, particularly sheet glass articles formed to be chemically temperable to a compressive stress CS of at least 600 MPa surface and a reinforced layer depth DoL of at least 30 μm, in particular In the manufacturing method of the said plate-shaped glass article formed by the method of any one of claim | item 1 -18,
-Continuously feeding the glass melt onto the metal melt;
-Shaping the glass melt in the traction direction into a strip of glass having a predetermined width and thickness, the strip being opposite the metal bath side facing the metal melt and the metal melt Forming a non-metal bus side of the side;
-Cooling the glass strip along the towing section, withdrawing the glass strip from the metal melt and preferably further transferring it into an aging device, for example a slow-cooling kiln;
The moisture content in the at least one region (B _A ) of the traction section, preferably in the aging device, is the water content W on the _upper side of the glass strip indicated by volume% and the lower side of the glass strip The water content W _below the following relationship:

A method in which a refers to a correction factor and corresponds to an integer value between 3 and 25, preferably a value of 15, and thus there is a moisture asymmetry of the gas. 20. The method according to claim 19, wherein the moisture asymmetry of the gas in at least one region (B _A ) of the traction section is perpendicular to each surface of the glass and opposite to the center of the glass. A method that exists at an interval of at least 50 mm measured in the direction. 21. Method according to claim 19 or 20, wherein at least one region (B _A ) of the traction section extends over a section of at least 1 m, preferably at least 3 m, particularly preferably at least 5 m in the traction direction. A method having a horizontal extent in which moisture asymmetry is formed.   22. A method according to any one of claims 19 to 21, wherein at least one region of the traction section is at least 0.5 m, preferably at least 1 m, particularly preferably parallel to the width of the glass article. Which has a horizontal extent of at least 2 m and more particularly advantageously takes at least a value less than half a meter less than the total width of the towed glass strip. The method according to any one of claims 19 to 22, the temperature of the glass article in the region of the aging device is moisture asymmetry exists, at least T _g -50K, method. 24. The method according to any one of claims 19 to 23, wherein the moisture asymmetry is:
-Introducing a wet gas into the aging device above the ribbon, and / or-introducing a dry gas into the aging device below the ribbon.
Here, wet refers to a gas when the absolute moisture content of the gas is higher than the absolute moisture content of the gas contacting the opposite side of the glass strip, and dry Refers to a gas when the absolute moisture content of the gas is lower than the absolute moisture content of the gas in contact with the opposite side of the glass strip.   25. A method according to any one of claims 19 to 24, wherein water vapor is supplied to the aging device on the upper side of the strip glass, and the mass flow rate of water vapor is at least 30 kg / h, preferably at least 50 kg. / H, particularly preferably at least 80 kg / h. 26. The method according to any one of claims 19 to 25, wherein the gas flow rate below the glass ribbon in the aging device is higher than 50 Nm < ³ > / h (standard cubic meters per hour), The process is preferably higher than 100 Nm ³ / h.   27. A method according to any one of claims 19 to 26, wherein at least one gas is introduced into the surface of the plate-like glass by means of a lance, wherein the lance spouts gas therethrough. A method having a plurality of holes that can be made.   28. The method according to claim 27, wherein the plurality of holes in the lance form an angle of 0 ° to 90 °, preferably 45 °, with the surface.   29. A method according to claim 27 or 28, wherein the minimum distance between the glass surface and the lance perpendicular to the at least one surface is at least 30 mm, preferably 50 mm.   30. The method according to any one of claims 19 to 29, wherein water vapor is added to the at least one gas or the gas consists of pure water vapor, wherein the water vapor is A method, eg supplied by a boiler and / or steam heater.   31. A method as claimed in any one of claims 19 to 30, wherein the temperature of the at least one gas having moisture adjusted as defined is at least 300 ° C, preferably at least 400 ° C, in particular A process which preferably has a temperature of at least 500 ° C., most preferably 600 ° C.   32. The method according to any one of claims 19 to 31, wherein a pressure difference exists in the region at least 50 mm from the surface of the glass ribbon between the upper side of the glass ribbon and the lower side of the glass ribbon. The pressure difference measured as is a method of 500 Pa or less. Highly chemically tempered sheet glass article, in particular a sheet glass article formed to be chemically temperable to a compressive stress CS of at least 600 MPa surface and a strengthened layer depth DoL of at least 30 μm, The asymmetry of the hydrogen content at the two glass surfaces is such that the average hydrogen content measured at a depth of 0.5 μm to 5 μm measured perpendicular to the glass surface towards the center of the glass is different. Where the average hydrogen content is measured by ToF-SIMS measurements and is shown as the signal height of the H ⁻ ion normalized to the height of the silicon signal. The glass article.   The glass article according to claim 33, wherein the plate-like glass article is formed as float glass, and the average hydrogen content on the surface of the glass article formed as the upper side in the float process is A glass article that is higher than the average hydrogen content at the glass surface formed as a side. 35. The glass article according to claim 33 or 34, wherein an average value of hydrogen content on the surface having a higher hydrogen content is H￣ _{wet, 0.5 μm} to _{5 μm,} and the center of the glass from the surface of the plate-like glass article. for differences ΔH¯ _wet the hydrogen content H¯ _5μm-25μm, measured as the average hydrogen content at a depth of from 5 [mu] m to 25 [mu] m towards the following inequality:
ΔH¯ _wet = H¯ _{wet, 0.5μm-5μm -H¯ 5μm-25μm} > 0
Applies to glass articles. 36. Glass article according to claim 35, wherein the [Delta] H soot _wet has a value greater than 0.001, preferably greater than 0.0015. A glass article according to any one of claims 33 to 36, the difference ΔH¯ _dry average, have a different sign to the ΔH¯ _wet, whereby, advantageously, the average value the difference ΔH¯ _wet is greater than 0.001, and the difference ΔH¯ _dry simultaneously average, less than -0.001, the glass article. _38. A glass article according to any one of claims 33 to 37, wherein the quotient _QΔH￣ of the difference between the mean values is:
Q _ΔH￣ = ΔH￣ _{wet type} / ΔH￣ _{dry type}
And the quotient has a value of less than -0.005, preferably has a value of less than -0.01, particularly preferably has a value of less than -0.1. A glass article formed as an aluminosilicate glass according to any one of claims 33 to 38, the composition advantageously having the following compositional range (% by weight):
SiO ₂ 40-70
Al ₂ O ₃ 5-20
B ₂ O ₃ 0-10
Na ₂ O 8-20
K ₂ O 0-5
MgO 0-10
CaO 0-2
ZrO ₂ 0-5
Other 0-5
Here, it is particularly preferred that the glass article has an Al ₂ O ₃ content of at least 5% by weight, more particularly preferably at least 10% by weight. 40. The glass article according to any one of claims 33 to 39, wherein the transformation temperatures T _{g and surfaces of} both _surfaces are different from each other, and an absolute value | ΔT _{g, surface} | Glass articles that are at least between 1K and 10K, preferably at least between 2K and 5K. 41. A glass article according to claim 40, wherein Tg _{, H +} refers to the transformation temperature of the glass surface having a higher hydrogen content and Tg _{, H-} is a glass surface having a lower hydrogen content. A glass article, wherein T _{g, H +} has a lower value than T _{g, H−} . A glass article according to any one of claims 33 to 41, Na ₂ O content in a surface having a higher average hydrogen content (wt%) is, the surface having a lower average hydrogen content Glass articles that are 0.2 to 0.7 percent lower than the Na ₂ O content in   43. Any of claims 33 to 42, which can be produced by a method according to any one of claims 1 to 18 or any one of claims 19 to 32, in particular produced by said method. The glass article according to claim 1. A chemically strengthened plate-like glass article, wherein the asymmetry of the hydrogen content at the two glass surfaces is measured from a depth of 0.5 μm to 5 μm measured towards the center of the glass perpendicular to the glass surfaces. The average hydrogen content measured in this way is configured to be different, wherein the average hydrogen content is measured by ToF-SIMS measurement and normalized to the height of the silicon signal H ⁻ ion signal height, where the normalized warp W _s after chemical strengthening is less than 300 μm, preferably less than 200 μm, particularly preferably less than 100 μm, And the compressive stress CS at their surface has a value of at least 600 MPa, and the reinforced layer depth DoL is at least 30 μm, where a higher average A glass article, wherein the compressive stress CS _{H +} at the surface having a hydrogen content has a lower value than the compressive stress CS _H− at the surface having a lower average hydrogen content. 45. The glass article of claim 44, wherein the Na ₂ O content (mass%) on the surface having a higher average hydrogen content is greater than the Na ₂ O content on the surface having a lower average hydrogen content. A glass article that is 0.2 to 0.7 percent lower.   The glass article according to claim 44 or 45, obtained by chemical strengthening of the glass article according to any one of claims 33 to 43.

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