Ultra-thin impact-resistant glass

Abstract

The present invention relates to an ultra-thin, chemically strengthened and then etched glass article (1) having a thickness of 0.4 mm or less. To improve impact resistance, the glass article (1) has a breaking height (given in mm) greater than 200 multiplied by the thickness (t (mm)) of the glass article. Furthermore, the glass article (1) has a breaking bend radius (given in mm) less than 100,000 multiplied by the thickness (t (mm)) of the glass article divided by the surface compressive stress (MPa) measured on the first surface (2).

Description

[Technical Field]

[0001] The present invention relates to ultra-thin, chemically strengthened glass articles with improved impact resistance and high flexibility. The present invention also relates to the use of high-strength flexible glass articles as flexible universal surfaces in flexible and printed electronics, sensors for touch control panels, fingerprint sensors, thin-film battery substrates, mobile electronic devices, semiconductor interposers, flexible and bendable displays, solar cells, or other applications requiring a combination of high chemical stability, temperature stability, low gas permeability, flexibility, and thin thickness. In addition to consumer and industrial electronics, the present invention can also be used for protective applications in industrial manufacturing or metrology.

[0002] Background technology Thin glasses of various compositions are suitable substrate materials for many applications where transparency, high chemical and heat resistance, and defined chemical and physical properties are important. For example, alkali-free glasses can be used for display panels and as electronic packaging materials in wafer format. Alkali-containing silicate glasses are used for filter coating substrates, touch sensor substrates, and fingerprint sensor module covers.

[0003] Aluminosilicate (AS) glass, lithium aluminosilicate (LAS) glass, borosilicate glass and soda-lime glass are widely used for applications such as covers for fingerprint sensors (FPS), protective covers and display covers, etc. In these applications, the glasses are usually chemically strengthened to achieve high mechanical strength measured by special tests such as three-point bending (3PB), ball drop, scratch resistance and others.

[0004] Chemical strengthening is a well-known process for increasing the strength of glasses such as soda-lime glass, aluminosilicate (AS) glass, lithium aluminosilicate (LAS), and borosilicate glass, which are used, for example, as cover glass in display applications. In this context, the surface compressive stress (CS) is typically 500–1,000 MPa, and the depth of the ion-exchange layer is typically greater than 30 μm, preferably greater than 40 μm. For safety protection applications in transportation or aviation, AS glasses may have an exchange layer greater than 100 μm. Typically, glasses with both a high CS and a high DoL are targeted for all of these applications, and glass thicknesses typically range from about 0.5 mm to 10 mm.

[0005] Currently, the continuous demand for new product functionality and wider application fields requires thinner and lighter glass substrates with high strength and flexibility. A typical application area for ultra-thin glass (UTG) is the protective cover of precision electronic devices. Currently, the increasing demand for new product functionality and the search for new and wider applications require thinner and lighter glass substrates with new properties, such as flexibility. Due to the flexibility of UTG, such glass has been investigated and developed as cover glass and displays for devices such as smartphones, tablets, watches, and other wearable devices. Such glass can also be used as cover glass for fingerprint sensor modules and as camera lens covers.

[0006] However, when glass sheets are thinner than 0.5 mm, they become increasingly difficult to handle, primarily due to defects that lead to breakage, such as cracks and chips at the edges of the glass. Also, the overall mechanical strength, as reflected in bending strength or impact strength, is significantly reduced. To increase bending strength, tempering of glass is crucial.

[0007] Typically, ultra-thin glass with a thickness of less than 0.5 mm can be produced by direct hot-forming methods, such as downdraw, overflow fusion, or special float processes. Redraw processes are also possible. Compared with thin glass that has been post-treated by chemical or physical methods (e.g., by grinding and polishing), directly hot-formed thin glass has much better surface uniformity and roughness because the surface is cooled from a high-temperature molten state to room temperature. The downdraw process can be used to produce glasses thinner than 0.3 mm, or even thinner than 0.1 mm, such as aluminosilicate glass, lithium aluminosilicate glass, alkali borosilicate glass, soda-lime glass, or alkali-free aluminoborosilicate glass.

[0008] Although a pristine hot-formed surface is preferred for many applications, chemically thinning thicker glass to UTG thickness may provide adequate or even better surface quality in certain cases. Additionally, handling, shipping, and processing may be easier with thicker glass than with UTG.

[0009] Chemical strengthening of UTG has been described in several patents. U.S. Patent Application Publication No. 2015183680 describes the strengthening of glass <0.4 mm thick with a limited central tension range and DoL >30 μm. However, problems such as fragility and self-destruction arise in ultra-thin tempered glass at DoL >30 μm. Furthermore, this patent application does not show how glass <0.4 mm thick is manufactured. International Publication No. 2014036267 claims that to have high flexural strength, glass must have a compressive stress-depth product greater than 21,000 μm·MPa, but such a high CS and DoL do not apply to ultra-thin glass.

[0010] The overall flexural and impact strength of ultra-thin glass is affected by several factors, including edge quality, surface quality, chemical strengthening, and external coatings. Several inventions have described methods for improving the strength of ultra-thin glass through chemical strengthening. As noted in U.S. Patent Application Publication No. 20160002103, ultra-thin glass sheets are more flexible and have exceptional thermal shock resistance due to chemical strengthening, making them easier to handle for processing. International Publication No. 2016 / 037589 describes edge pretreatment to enhance the flexural strength of ultra-thin glass. International Publication No. 2014 / 139147 discloses tempering of glass <0.5 mm thick with a compressive stress <700 MPa and a DoL <30 μm. However, here too, ultra-thin tempered aluminosilicate glass has low mechanical resistance and tends to break easily when contacted with sharp, hard objects. It has generally been thought that to obtain flexible glass with an optimal bending radius, the DoL (depth of ion exchange layer) must reach a high value of approximately 0.1 to 0.2 times the thickness (in μm) of the respective glass. However, it has been found that the impact resistance of known tempered ultra-thin glass is very low. Impact resistance is the property of UTG that allows it to withstand impact forces, for example, when a glass article is dropped and its surface comes into contact with an external object, or when an external object falls onto the surface of the glass article. Therefore, such tempered flexible glass articles may easily break when struck hard by an external object. To improve the impact resistance of thin foldable glass elements, WO 2017 / 123899 describes providing a protective polymer layer on the outer surface of the glass element to prevent direct contact with external objects.

[0011] The sheer number of glass thicknesses, tempering procedures, and results (different CS, DoL, and CT) associated with UTG makes it difficult to predict whether a glass article will be usable in a specific application. However, testing the actual finished product (e.g., by dropping a folding display cover on an object until it breaks) is not only inefficient but also wasteful. To reduce the risk of damage to customers, glass manufacturers and processors have developed numerous tests to prove the contact resistance and flexibility of tempered ultra-thin glass, such as three-point bend (3PB), ball drop, and scratch resistance. However, these tests are complex and frequently fail.

[0012] In contrast to thick glass, ultra-thin glass generally presents a more complex situation regarding strength. The objective of the present invention is to improve the impact resistance, overall flexibility, and reliability of ultra-thin glass, preferably without an additional polymer layer laminated onto the first surface of the article that may come into contact with a hard object.

[0013] Technical terms explained Glass Article: The glass article can be of any size, such as a long, ultra-thin rolled ribbon of glass (glass roll), a large glass sheet, smaller glass elements cut from a glass roll or from a glass sheet, or a single small glass article (e.g., a FPS or display cover glass), etc.

[0014] Ultra-thin glass: For the purposes of the present invention, ultra-thin glass is glass having a thickness of 0.4 mm or less, preferably 0.14 mm or less, and particularly more preferably 0.1 mm or less.

[0015] Thickness (t): The thickness of a glass article is the arithmetic mean of the thicknesses of the measured samples.

[0016] Compressive stress (CS): Compression induced between the glass meshes after ion exchange on the surface layer of glass. Such compression cannot be relieved by deformation of the glass and remains as stress. CS decreases from a maximum value at the surface of the glass article (surface CS) toward the inside of the glass article. Commercially available testing machines, such as the FSM6000 (Lukeo Co., Ltd., Tokyo, Japan), can measure CS using a waveguide mechanism.

[0017] Depth of Layer (DoL): The thickness of the ion-exchange layer on the glass surface where CS exists. Commercially available testing machines, such as the FSM6000 (Lukeo Co., Ltd., Tokyo, Japan), can measure DoL using a waveguide mechanism.

[0018] Internal Tensile Stress (CT): When CS is induced on one or both sides of a glass sheet, to balance the stresses according to the third principle of Newton's law, a tensile stress must be induced in the central region of the glass, which is called internal tensile stress. CT can be calculated from the measured CS and DoL.

[0019] Surface roughness (R a ): A measure of surface texture. It is quantified by the vertical deviation of the actual surface from the ideal morphology. Conventionally, the amplitude parameter characterizes a surface based on the vertical deviation from the centerline of the roughness profile. R a is the arithmetic mean of the absolute values ​​of their vertical displacements.

[0020] Breaking Height (also known as "Pen Drop Height"): Breaking Height is the height (given in mm) that an object of a specified weight can be dropped onto a chemically strengthened, ultra-thin glass article before the glass article breaks (i.e., cracks). Breaking Height is determined by the Pen Drop Test, which is described in more detail below.

[0021] Breaking Bending Radius (BBR): In this invention, BBR is adopted as a measure of flexibility. The breaking bending radius (given in mm) is the smallest radius (r) of the arc at the bending position at which the glass article reaches its maximum deflection before twisting, damaging, or breaking. It is measured as the inside curvature of the glass material at the bending position. The smaller the radius, the greater the flexibility and deflection of the glass. The bending radius is a parameter that depends on the glass thickness, Young's modulus, and strength. Chemically strengthened ultra-thin glass has a very thin thickness, a low Young's modulus, and high strength. All three factors contribute to a low bending radius and excellent flexibility. The test for determining BBR is described in detail below.

[0022] Detailed Description of the Invention The present invention provides a chemically strengthened and then etched glass article having a thickness (t) of less than 0.4 mm, the glass article having a first surface, a second surface, and a compressive stress region extending from the first surface to a first depth (DoL) within the glass article, the region being defined by a compressive stress (CS), the surface CS at the first surface being at least 100 MPa. The glass article has a failure height (given in mm) of at least 200 times the thickness (t in mm) of the glass article. The breaking height is determined by a pen drop test, in which a glass article is attached by its second surface to a 100 μm thick substrate consisting of a 50 μm thick layer of polyethylene (PE) material and a 50 μm thick layer of pressure-sensitive adhesive (PSA) material, with the second surface in contact with the PSA layer, and the substrate with the attached glass article is placed on a rigid support with the first surface of the glass article facing upward and then impacted until breaking with a 4.5 g pen with a 300 μm diameter tungsten carbide ballpoint tip. Furthermore, glass articles according to the present invention have a breaking bend radius (given in mm) that is smaller than the thickness (t (mm)) of the glass article multiplied by 100,000 and divided by the surface compressive stress (MPa) measured at the first surface.

[0023] The inventors have discovered that chemically strengthening ultra-thin glass articles improves bending performance, but also reduces impact resistance, which is highly undesirable for most UTG applications. Surprisingly, the inventors have found that removing a small amount of material from the first surface of a strengthened ultra-thin glass article by etching can significantly improve the impact resistance of the article. Glass articles that have been strengthened and subsequently etched according to the present invention have both improved impact resistance and high flexibility.

[0024] Such glass articles according to the present invention have an optimized stress profile, which has a balanced small bending radius and high impact resistance. Surprisingly, it has been found that the glass article will be reasonably strong enough to accommodate ultra-thin glass article applications, especially in everyday use, if the following conditions are met: a) the glass article has a breaking height (given in mm) of ≥ 200 x t in the pen drop test described above (t is the numerical value of the respective thickness of the glass article in "mm"); and b) its breaking bending radius (given in mm) is <100,000 × t / CS, where t is the thickness of the glass article (given in "mm") and CS is the numerical value of the surface compressive stress (given in "MPa"); i.e., in the latter calculation, the product is divided by the numerical value corresponding to the respective surface compressive strength (given in MPa) at the first surface of the glass article.

[0025] These criteria allow for the determination of whether a reinforced ultra-thin glass article has adequate strength and flexibility for its intended use before it is incorporated into a product. Surprisingly, it has been found that the fracture height is strongly correlated with the thickness and surface condition of the glass. Thus, thinner glass is particularly susceptible to fracture due to impact.

[0026] Surprisingly, the inventors have found that the breaking height criteria for ultra-thin glass can be explained by the coefficient 200 of the present invention and the thickness of the glass article. The coefficient of the present invention is valid when the breaking height of a glass article is determined by a pen drop test. In this dynamic test, a sample of a glass article is prepared as follows: the glass article is placed on a 100 μm substrate on its second surface side. The substrate consists of a 50 μm thick layer of polyethylene (PE) material and a 50 μm thick layer of 3M pressure sensitive adhesive (PSA) material. To form and ensure a uniform adhesion between the glass article and the PSA layer, a 2 g / mm 2 The glass article is placed on a rigid support (e.g., a table) with the PE layer in contact with the support and the first surface of the glass article facing upward. The unlaminated first surface of the glass article is then impacted with a specified test pen. The test pen is a 4.5 g pen with a 300 μm diameter ballpoint tip made of tungsten carbide. For the test, the pen is placed in the tester at a recorded height above the glass article. The longitudinal axis of the pen is oriented perpendicular to the first surface of the glass article, with the ballpoint tip facing the glass article. The tester then drops the pen onto the first surface. If the glass article does not break, the pen drop height is increased stepwise by a specified amount, and the glass article is moved at least 3 mm to avoid double or multiple impacts on the same point on the glass article. This procedure is repeated until the glass article breaks. The test is performed on small samples (e.g., 20 mm x 50 mm) at room temperature of approximately 20°C and 50% relative humidity. For testing larger glass articles, small samples are cut using a diamond cutting wheel. No additional edge treatment is performed on the small samples. The breaking height (also known as "pen drop height" = PDH) is the maximum height to which the glass article can be subjected before it breaks. Breaking means that the glass article develops a visible surface crack (cracking) or initially breaks into two or more pieces. Breaking is determined by visual inspection.

[0027] This test is tailored and particularly suitable for ultra-thin glass articles and reproduces in a very simple manner the problem mentioned above, namely impact contact between a glass article (e.g. a touch display) and an external object when the glass article is dropped or impacted. In an advantageous embodiment of the invention, the glass article has a breaking height (given in mm) in the above-mentioned pen drop test of ≥ 300 x t (t being the numerical value of the respective thickness of the glass article in "mm").

[0028] Surprisingly, the inventors have found that the criteria for the fracture bend radius of ultra-thin glass can be explained by the coefficient of 100,000 of the present invention, the thickness of the glass article, and the measured surface CS. The coefficient of the present invention is valid when the fracture bend radius of a glass article is determined by a two-point bending test as described herein. The fracture bend radius is determined on a small sample (e.g., 20 mm x 70 mm) using a UTM (universal testing machine) at a room temperature of about 20°C and a relative humidity of about 50%. If a larger size glass article is to be tested, a small sample is cut using a diamond cutting wheel. The cut sample is then polished at the edges. The glass article is placed in a bending position, and both ends are placed between two parallel plates (steel plates). The distance between the plates is then reduced, resulting in a smaller bending radius of the glass article. The loading rate here is 60 mm / min. The distance between the plates as the ultra-thin glass article twists, is damaged, or breaks into two or more pieces, as measured by the UTM software signal, is recorded. From that distance, the corresponding bending radius of the glass article at the time of breakage can be calculated, which is known to those skilled in the art and is described, for example, by MJ Matthewson et al. (Journal of the American Ceramic Society, Vol. 69, No. 11, pages 815-821, November 1986). Matthewson describes a two-point bending test using glass fibers. However, the considerations made there can be transferred to the flat articles of the present invention. When small glass articles are tested, a portion of the outer surface of the glass sample being tested should touch each plate just before breaking, twisting, or damage.

[0029] This two-point bending test is adjusted for ultra-thin glass articles, is particularly suitable therefor, and reproduces in a very simple manner the problem described above, namely the bending of a glass article (e.g., an FPS or a touch display) when a load is applied. In the context of the present invention, the two-point bending method has been found to be more reliable than other known bending strength tests such as three-point and four-point bending tests.

[0030] In an advantageous embodiment of the invention, the fracture bending radius (mm) of the chemically strengthened glass article is less than the result of multiplying the thickness (t (mm)) of the glass article by 80,000 and dividing the result by the value of the surface compressive stress (MPa) measured on the first surface (<t×80,000 / CS). Preferably, the fracture bending radius (mm) may also be less than the result of multiplying the thickness (t (mm)) of the glass article by 70,000 and dividing the result by the value of the surface compressive stress (MPa) measured on the first surface (<t×70,000 / CS). In some variants, the fracture bending radius (mm) may also be less than the result of multiplying the thickness (t (mm)) of the glass article by 60,000 and dividing the result by the value of the surface compressive stress (MPa) measured on the first surface (<t×60,000 / CS).

[0031] As mentioned above, ultrathin glass articles are used in many areas of everyday use, such as covers for flexible / foldable smartphones and tablets. To increase the strength of cover glass, tempering, preferably chemical tempering, is performed. In this regard, the prior art generally assumed that a high compressive strength and a DoL of approximately 0.1 to 0.2 times the thickness (given in μm) were adequate. However, the impact resistance of such tempered glass articles has been insufficient until now. Surprisingly, the inventors have discovered that glass articles according to the present invention can be made more reliable in terms of flexibility and impact resistance by an additional surface modification process, i.e., etching after chemical tempering. This is due to the improved and optimized stress profile of the glass articles according to the present invention. Conversely, if an ultrathin glass article satisfies the claimed breaking height and the claimed breaking bend radius (respectively for the thickness and measured surface CS), the risk of fracture of the glass article of the present invention during use (e.g., as a cover glass for a fingerprint sensor) is low.

[0032] As mentioned above, chemically strengthened glass articles according to the present invention can have quite different sizes. Therefore, when determining the breaking height and breaking bend radius, the following must be taken into consideration: For larger glass articles (e.g., glass rolls or large glass sheets), multiple samples are measured for breaking height using a pen drop test. For this, an N value of random samples is obtained. N must be high enough to obtain a statistically guaranteed average value. Preferably, at least 20, more preferably at least 30 samples are tested. The number of samples depends on the respective size of the glass article being tested. The measurements are statistically evaluated using the Weibull method. The B10 value of the Weibull distribution (i.e., the calculated height (mm) at which 10% of the samples break) is determined and this is taken to represent the breaking height in the claims.

[0033] However, for small glass articles (e.g., small individual cover glasses), a single measurement of the breaking height is sufficient and is taken to represent the breaking height in the claims.

[0034] If the number of measured values ​​is between 2 and 19 or 29 or more, the average of the measured breaking heights is taken to represent the breaking height in the claims.

[0035] For the breaking bending radius, an average value can be calculated. For this purpose, a random sample of N values ​​is taken. The number of samples depends on the respective size of the glass article being evaluated. N should preferably be large enough to obtain a statistically guaranteed average value. Preferably, at least 20, more preferably at least 30 samples are tested. The breaking bending radius R1...R of the random samples is therefore N N values ​​for are taken, and for these random sample values, the mean

number

number

[0036] This average breaking bend radius is taken to represent the breaking bend radius in the claims, although for small glass articles (e.g., individual small cover glasses), a single measurement of the breaking bend radius may be sufficient and will be considered to represent the breaking bend radius in the claims.

[0037] The mean and variance of the fracture heights are calculated accordingly.

[0038] In an advantageous embodiment, the chemically strengthened and then etched glass article has a breaking height at B10 (given in mm) that is at least the thickness (t in mm) of the glass article multiplied by 150.

[0039] In one embodiment, the glass is an alkali-containing glass, such as alkali aluminosilicate glass, alkali silicate glass, alkali borosilicate glass, alkali aluminoborosilicate glass, alkali boron glass, alkali germanate glass, alkali borogermanate glass, alkali soda-lime glass, and combinations thereof.

[0040] Ultra-thin glass articles according to the present invention have thicknesses of 400 μm or less, preferably 330 μm or less, equally preferably 250 μm or less, even more preferably 210 μm or less, preferably 180 μm or less, equally preferably 150 μm or less, and even more preferably 130 μm or less. Particularly preferred embodiments have thicknesses of 100 μm or less, more preferably 80 μm or less, more preferably 75 μm or less, more preferably 70 μm or less, more preferably 65 μm or less, more preferably 60 μm or less, more preferably 55 μm or less, even more preferably 50 μm or less, more preferably 45 μm or less, more preferably 40 μm or less, more preferably 35 μm or less, even more preferably 30 μm or less, more preferably 25 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. Such particularly thin glass articles are desirable for the various applications described above. In particular, the thin thickness provides the flexibility of glass. The thickness may be at least 5 μm.

[0041] According to an advantageous embodiment, the glass article may be a flat and / or flexible and / or deformable article. A "flat" article may, for example, be a substantially planar or planar glass article. However, "flat" in the sense of the present invention also includes articles that are deformable or deformed in two or three dimensions.

[0042] Glass articles that have been strengthened and then etched according to the present invention have a distinct modified first surface resulting from the removal of an etched thickness after chemical strengthening. The etched surface treatment removes material from the first strengthened surface. The final thickness of the glass article after etching is slightly less than the thickness of the product after the strengthening process. In advantageous embodiments, the thickness removal (t) from the first surface is removed ) (i.e., the difference between the thickness of the "chemically strengthened glass article" and the thickness of the "chemically strengthened and then etched glass article") is ≦0.005 mm, preferably ≦0.004 mm, preferably ≦0.003 mm. Glass articles that have undergone thickness removal of ≦0.002 mm, more preferably ≦0.001 mm, and / or ≧0.0002 mm are preferred. Thickness removal means that after the etching process, the DoL of the first surface is slightly lower than before the etching process. The DoL is reduced. This slight etching can significantly increase impact resistance. According to advantageous embodiments, the surface-modified glass article has an increase in pen drop height of >20%, preferably >30%, more preferably >40%, more preferably >50% compared to a corresponding chemically strengthened, unetched glass article.

[0043] Etching can be carried out in various ways. According to a first advantageous variant, the surface of the glass article is etched with an acidic solution, which is preferably at least one aqueous solution selected from the group consisting of HF, H2SO4, HNO3, HCl, and NH4HF2. Other advantageous etching substances may be NaHF2 / HCl, organic acids such as acetic acid or citric acid. According to a second advantageous variant, the surface of the glass article is etched with an alkaline solution, which is preferably at least one aqueous solution selected from the group consisting of LiOH, NaOH, and KOH, or for example NH4OH.

[0044] According to a further advantageous embodiment, the glass article has a second compressive stress region extending from the second surface to a second depth (DoL) within the glass article, this region being defined by a compressive stress (CS), the surface compressive stress of the second surface (3) being at least 100 MPa. Preferably, the second surface has also been subjected to a surface modification process by etching after being chemically strengthened as described above.

[0045] The performance of tempered and then etched glass articles is advantageous when the surface compressive stress (CS) of the glass article is greater than 100 MPa, preferably greater than 200 MPa, more preferably greater than 300 MPa, more preferably greater than 400 MPa, more preferably greater than 500 MPa, and more preferably greater than 600 MPa. According to preferred embodiments of the present invention, CS is 700 MPa or more preferably greater than 700 MPa, more preferably greater than 800 MPa, more preferably greater than 900 MPa, and even more preferably greater than 1000 MPa. However, CS should not be too high, because otherwise the glass may be prone to self-destruction. Preferably, CS is 2000 MPa or less, preferably 1600 MPa or less, advantageously 1500 MPa or less, and more preferably 1400 MPa or less. Some advantageous embodiments have a CS of 1300 MPa or less, or even 1200 MPa or less.

[0046] The depth of layer (DoL) of the glass article before etching is, in advantageous embodiments, >1 μm to <40 μm. Preferably, the DoL is ≦30 μm, preferably ≦20 μm. Preferably, the DoL is ≧3 μm, preferably ≧5 μm, preferably ≧7 μm. For ultra-thin glass having a thickness of up to 100 μm, preferably the DoL is ≦17 μm, preferably ≦15 μm, also preferably ≦13 μm, further preferably ≦11 μm, also preferably ≦10 μm.

[0047] Furthermore, it is advantageous for the glass article according to the invention if the glass article has a central tensile stress (CT) of at least 2 MPa, more preferably at least 28 MPa, more preferably at least 35 MPa, more preferably at least 43 MPa, more preferably at least 50 MPa, more preferably at least 66 MPa, more preferably at least 79 MPa, more preferably at least 90 MPa, more preferably at least 100 MPa.

[0048] To further improve the properties of the glass article according to the present invention, it may include a coating layer, also called a protective layer, on at least one surface, which comprises a coating material. The protective layer can be applied by various methods, such as chemical vapor deposition (CVD), dip coating, spin coating, inkjet printing, casting, screen printing, painting, bar coating, roll-to-roll coating, and spraying, although direct application of a foil using a soft solid layer may be advantageous. However, the present invention is not limited to these methods. Suitable materials are also known in the art.

[0049] The coated layer may be, for example, a silicone polymer, a sol-gel polymer, a polycarbonate (PC), a polyethersulfone, a polyacrylate, a polyimide (PI), an inorganic silica / polymer hybrid, a cycloolefin copolymer, a polyolefin, a silicone resin, a polyethylene (PE), a polypropylene, a polypropylene-polyvinyl chloride, a polystyrene, a styrene-acrylonitrile copolymer, a thermoplastic polyurethane resin (TPU), a polymethyl methacrylate (PMMA), an ethylene-vinyl acetate copolymer, a polyethylene terephthalate (PET), a polybutylene terephthalate, a polyamide (PA), a polyacetal, a poly It may comprise or consist of a polymeric material that may be selected from the group consisting of phenylene oxide, polyphenylene sulfide, fluorinated polymers, chlorinated polymers, ethylene-tetrafluoroethylene (ETFE), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF), polyethylene naphthalate (PEN), terpolymers made from tetrafluoroethylene, terpolymers made from hexafluoropropylene, and terpolymers made from vinylidene fluoride (THV) or polyurethane, or mixtures thereof.

[0050] Alternatively, or in addition, the coated layer may comprise or consist of a thermosetting reactive resin, which is a polymer selected from the group consisting of phenoplasts, phenol formaldehyde resins, aminoplasts, urea formaldehyde resins, melamine formaldehyde resins, epoxide resins, unsaturated polyester resins, vinyl ester resins, phenacrylate resins, diallyl phthalate resins, silicone resins, crosslinked polyurethane resins, polymethacrylate reactive resins, and polyacrylate reactive resins, acrylic resins, acrylic-siloxane hybrids, epoxy siloxane hybrids, etc. Such coating materials for the coated layer are capable of forming hard coatings with high hardness (preferably pencil hardness >2H).

[0051] Thus, the coated layer may include a polymeric coating or a hard coating, or both.

[0052] The hard coating may be applied directly to the surface of the glass article, or may be applied over a polymeric coating layer that has previously been applied / laminated to the glass article. In addition to improving impact resistance, the additional hard coating can improve the scratch resistance of the polymeric layer.

[0053] Typically, additional coated layers can improve the impact resistance of the glass article.

[0054] The breaking height of an ultra-thin glass article can be significantly increased if a coating layer, preferably having a thickness t2 of ≥ 10 μm, advantageously ≥ 20 μm, is provided on the first or second surface, or on both the first and second surfaces, of the glass article according to the present invention. Preferably, the coated layer is applied to the first surface (top coating). Preferably, the coated layer may be a polymeric protective layer or may be a polymeric protective layer with an additional hard coating.

[0055] Preferably, the thickness t2 of the coating layer provided on one surface (first surface or second surface) can be t2≦(0.3−t), where t is the thickness of the uncoated glass article. For example, for a glass article with a thickness of 50 μm, the thickness t2 of the coating layer can be ≦250 μm, preferably ≦200 μm, or ≦180 μm, or ≦160 μm, or ≦140 μm. The desired thickness t2 depends, for example, on the type of coating material. Coated layers containing hard coating materials can be even thinner. In an advantageous variant, t2 can be ≦(0.25−t) or ≦(0.2−t). Regardless of the thickness of the uncoated glass article, the thickness of the coated layer can advantageously be ≦250 μm, preferably ≦200 μm, or ≦180 μm, or ≦160 μm, or ≦140 μm, or ≦120 μm, or ≦100 μm.

[0056] According to an advantageous embodiment of the present invention, the coated glass article, when provided with a coated layer having a thickness t2≦(0.3−t) on the first and / or second surface, has a breaking height (given in mm) of ≧500×t, where t is the thickness (mm) of the uncoated glass article. The breaking height is determined by a pen drop test corresponding to the test described above. If the first surface of the glass article is coated, the coated layer is impacted by a pen during the pen drop test. If the second surface is coated, the coated layer is attached to a 100 μm thick substrate to determine the breaking height. That is, for this dynamic test, coated samples of the glass article are manufactured and tested under the same conditions as the uncoated glass article described above.

[0057] Preferably, at least a first surface of the glass article is coated with a coating layer (top coating). Alternatively, it is also possible and advantageous to coat a second surface of the glass article with a coating layer (bottom coating). An advantageous variant of the glass article can have both a top coating and a bottom coating (double-sided coating). The coating materials for the top coating and / or the bottom coating can be the same or different.

[0058] In one advantageous variant of the glass article with a double-sided coating, the glass article is embedded between polymer layers selected from the group consisting of the polymer materials mentioned above.

[0059] In an advantageous development, the coated glass article having a coated layer on the first surface and / or the second surface has, in the above-mentioned pen drop test, a breaking height (given in mm) of ≥ 600 × t (t being the numerical value of the respective thickness of the uncoated glass article in "mm").

[0060] According to a preferred embodiment of the present invention, a coated glass article having a coating layer on its first surface with a thickness t2≦(0.3−t) has a breaking height (given in mm) that is at least the thickness (t (mm)) of the uncoated glass article multiplied by 500, preferably by 600, and this breaking height is determined by a pen drop test in which the glass article is attached on its second surface to a 100 μm thick substrate consisting of a 50 μm thick layer of polyethylene (PE) material and a 50 μm thick layer of pressure-sensitive adhesive (PSA) material, with the second surface in contact with the PSA layer, the substrate with the attached glass article placed on a rigid support, the first surface of the glass article facing upwards, and the coating layer is impacted with a 4.5 g pen with a 300 μm diameter tungsten carbide ball point tip until the glass article breaks.

[0061] In an advantageous further development, a coated layer (advantageously comprising the above-mentioned polymeric and / or hard coating material) may be provided on at least one edge of the glass article in order to improve the bending properties of the glass article and to improve the edge's resistance to forces / impacts during assembly and use, etc. Preferably, four glass edges are covered with the coating layer. Preferably, the breaking bend radius (given in mm) is <100,000 x t / CS.

[0062] The glass article may be further coated on the first surface for, for example, anti-reflective, anti-scratch, anti-fingerprint, anti-microbial, anti-glare, and combinations of these functions.

[0063] These and other aspects, advantages, and features are described in more detail in the following paragraphs, drawings, and appended claims.

[0064] To achieve good chemical strengthening performance, the glass should contain a significant amount of alkali metal ions, preferably Na2O, and the addition of smaller amounts of K2O to the glass composition can also improve the chemical strengthening rate. Furthermore, it has been found that the addition of Al2O3 to the glass composition can significantly improve the strengthening performance of the glass.

[0065] SiO2 is the primary glass network former in the glass of the present invention. Furthermore, Al2O3, B2O3, and P2O5 can also be used as glass network formers. The total content of SiO2, B2O3, and P2O5 should not be less than 40% for conventional manufacturing methods. Otherwise, the glass sheet may be difficult to form, become brittle, and lose transparency. A high SiO2 content requires high melting and working temperatures for glass production, which should usually be less than 90%. In a preferred embodiment, the SiO2 content in the glass is 40 to 75% by weight, more preferably 50 to 70% by weight, and even more preferably 55 to 68% by weight. In another preferred embodiment, the SiO2 content in the glass is 55 to 69% by weight, more preferably 57 to 66% by weight, and even more preferably 57 to 63% by weight. In a further preferred embodiment, the SiO2 content in the glass is 60 to 85 mass%, more preferably 63 to 84 mass%, and even more preferably 63 to 83 mass%. In another further preferred embodiment, the SiO2 content in the glass is 40 to 81 mass%, more preferably 50 to 81 mass%, and even more preferably 55 to 76 mass%. Addition of B2O3 and P2O5 to SiO2 can modify the network properties and lower the melting temperature and working temperature of the glass. The network-forming components of the glass also have a significant effect on the CTE of the glass.

[0066] Furthermore, B2O3 in the glass network forms two different polyhedral structures, which improves compatibility with external forces. The addition of B2O3 typically results in lower thermal expansion and a lower Young's modulus, which leads to better thermal shock resistance and a slower chemical strengthening rate, thereby facilitating low CS and low DoL. Therefore, the addition of B2O3 to ultra-thin glass can significantly improve the chemical strengthening process window and the ultra-thin glass, and broaden the practical applications of chemically strengthened ultra-thin glass. In preferred embodiments, the amount of B2O3 in the glass of the present invention is 0 to 20 wt%, more preferably 0 to 18 wt%, and more preferably 0 to 15 wt%. In some embodiments, the amount of B2O3 may be 0 to 5 wt%, preferably 0 to 2 wt%. In other embodiments, the amount of B2O3 may be 5 to 20 wt%, preferably 5 to 18 wt%. If the amount of B2O3 is too high, the melting point of the glass may become too high. Furthermore, chemical strengthening performance is reduced when the amount of B2O3 is too high, and B2O3-free embodiments may be preferred.

[0067] Al2O3 acts as both a glass network former and a glass network modifier. [AlO4] tetrahedra and [AlO6] hexahedrons are formed in the glass network depending on the amount of Al2O3, and they can adjust the ion exchange rate by changing the size of the spaces for ion exchange within the glass network. Generally, the content of this component varies depending on the type of glass. Therefore, some glasses of the present invention preferably contain Al2O3 in an amount of at least 2% by weight, more preferably at least 10% by weight, or even at least 15% by weight. However, if the Al2O3 content is too high, the melting temperature and working temperature of the glass become too high, and crystals tend to form, causing the glass to lose transparency and flexibility. Therefore, some glasses of the present invention preferably contain Al2O3 in an amount of at most 30% by weight, more preferably at most 27% by weight, and even more preferably at most 25% by weight. Some advantageous embodiments may contain Al2O3 in an amount of up to 20 wt%, preferably up to 15 wt% or up to 10 wt%, or even more preferably up to 8 wt%, preferably up to 7 wt%, preferably up to 6 wt%, preferably up to 5 wt%. Some glass embodiments may be Al2O3-free. Other advantageous glass embodiments may contain at least 15 wt%, preferably at least 18 wt% Al2O3, and / or up to 25 wt%, preferably up to 23 wt%, more preferably up to 22 wt% Al2O3.

[0068] Alkali oxides, such as K2O, Na2O, and Li2O, act as glass network modifiers. They can destroy the glass network and form non-bridging oxides within the glass network. Adding alkalis can lower the working temperature of the glass and increase the CTE of the glass. Na + / Li + , Na + / K + , Li + / K +The sodium and lithium content is important for chemically toughenable ultrathin flexible glass, since ion exchange of LiO is an essential step for toughening; without the alkali, the glass would not be toughened. However, sodium is preferred over lithium, because lithium can significantly reduce the diffusivity of the glass. Therefore, some glasses of the present invention preferably contain LiO in an amount of up to 7% by weight, preferably up to 5% by weight, more preferably up to 4% by weight, more preferably up to 2% by weight, more preferably up to 1% by weight, and more preferably up to 0.1% by weight. Some preferred embodiments are even LiO-free. Depending on the type of glass, the lower limit for LiO may be 3% by weight, preferably 3.5% by weight.

[0069] The glass of the present invention preferably contains Na2O in an amount of at least 4 wt%, more preferably at least 5 wt%, more preferably at least 6 wt%, more preferably at least 8 wt%, and more preferably at least 10 wt%. Sodium is very important for chemical strengthening performance because chemical strengthening preferably involves ion exchange of sodium in the glass with potassium in the chemical strengthening medium. However, the sodium content should not be too high because it can severely deteriorate the glass network and make the glass very difficult to form. Another important factor is that ultra-thin glass should have a low CTE, and to meet such requirements, the glass should not contain too much Na2O. Therefore, the glass preferably contains Na2O in an amount of up to 30 wt%, more preferably up to 28 wt%, more preferably up to 27 wt%, more preferably up to 25 wt%, and more preferably up to 20 wt%.

[0070] The glass of the present invention may contain K2O. However, because the glass is preferably chemically strengthened by exchanging sodium ions in the glass for potassium ions in the chemical strengthening medium, too much K2O in the glass can impair chemical strengthening performance. Therefore, the glass of the present invention preferably contains K2O in an amount of up to 10% by weight, more preferably up to 8% by weight. Some preferred embodiments contain up to 7% by weight, and other preferred embodiments contain up to 4% by weight, more preferably up to 2% by weight, more preferably up to 1% by weight, and more preferably up to 0.1% by weight. Some preferred embodiments are even K2O-free.

[0071] However, because the glass network may be severely deteriorated and the glass may become extremely difficult to form, the total alkali content should preferably be 35% by weight or less, preferably 30% by weight or less, more preferably 28% by weight or less, more preferably 27% by weight or less, and even more preferably 25% by weight or less. Some embodiments have an alkali content of up to 16% by weight, preferably up to 14% by weight. Another important factor is that ultra-thin glass should have a low CTE, and to meet such requirements, the glass should not contain too many alkali elements. However, as discussed above, to facilitate chemical strengthening, the glass should contain alkali elements. Accordingly, the glasses of the present invention preferably contain alkali metal oxides in an amount of at least 2% by weight, more preferably at least 3% by weight, more preferably at least 4% by weight, more preferably at least 5% by weight, and more preferably at least 6% by weight.

[0072] Alkaline earth oxides, such as MgO, CaO, SrO, and BaO, act as network modifiers and lower the glass-forming temperature. Addition of these oxides can adjust the CTE and Young's modulus of the glass. Alkaline earth oxides have the very important function of altering the refractive index of the glass to meet specific requirements. For example, MgO can lower the refractive index of the glass, while BaO can increase it. The mass content of alkaline earth oxides should preferably be 40% by weight or less, preferably 30% by weight or less, preferably 25% by weight or less, or even 20% by weight or less, more preferably 15% by weight or less, more preferably 13% by weight or less, and more preferably 12% by weight or less. Some embodiments of the glass may contain up to 10% by weight, preferably up to 5% by weight, and more preferably up to 4% by weight of alkaline earth oxides. Excessive amounts of alkaline earth oxides can deteriorate chemical strengthening performance. The lower limit for alkaline earth oxides may be 1% by weight or 5% by weight. Furthermore, too much alkaline earth oxide may increase the tendency to crystallize. Some advantageous embodiments may be free of alkaline earth oxides.

[0073] Some transition metal oxides in glass, such as ZnO and ZrO2, have similar functions to alkaline earth oxides and may be included in some embodiments. Other transition metal elements, such as Nd2O3, Fe2O3, CoO, NiO, VO5, MnO2, TiO2, CuO, CeO2, and Cr2O3, function as colorants to produce glasses with specific optical or photonic functions, such as color filters or light converters. As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents in amounts of 0-2% by weight. Rare earth oxides can also be added in amounts of 0-5% by weight to impart magnetic, photonic, or optical functionality to the glass sheet.

[0074] The following advantageous compositions relate to various types of glass before toughening.

[0075] In one embodiment, the ultra-thin flexible glass is an alkali metal aluminosilicate glass containing the following components in the indicated amounts (by weight): [Table 1]

[0076] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents in amounts of 0-2% by weight. Rare earth oxides can also be added in amounts of 0-5% by weight to impart magnetic, photonic, or optical functionality to the glass sheet.

[0077] The alkali metal aluminosilicate glass of the present invention preferably comprises the following components in the indicated amounts (% by weight): [Table 2]

[0078] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0079] Most preferably, the alkali metal aluminosilicate glass of the present invention comprises the following components in the amounts (wt%) indicated: [Table 3]

[0080] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0081] In one embodiment, the ultra-thin flexible glass is a soda-lime glass containing the following components in the amounts (by weight %) indicated: [Table 4]

[0082] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0083] The soda-lime glass of the present invention preferably comprises the following components in the amounts (% by weight) indicated: [Table 5]

[0084] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0085] The soda-lime glass of the present invention preferably comprises the following components in the amounts (% by weight) indicated: [Table 6]

[0086] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0087] The soda-lime glass of the present invention preferably comprises the following components in the amounts (% by weight) indicated: [Table 7]

[0088] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0089] Most preferably, the soda-lime glass of the present invention comprises the following components in the amounts (% by weight) indicated: [Table 8]

[0090] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0091] Most preferably, the soda-lime glass of the present invention comprises the following components in the amounts (% by weight) indicated: [Table 9]

[0092] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0093] In one embodiment, the ultra-thin flexible glass is a lithium aluminosilicate glass containing the following components in the indicated amounts (by weight): [Table 10]

[0094] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents in amounts of 0-2% by weight. Rare earth oxides can also be added in amounts of 0-5% by weight to impart magnetic, photonic, or optical functionality to the glass sheet.

[0095] The lithium aluminosilicate glass of the present invention preferably comprises the following components in the amounts (wt%) indicated: [Table 11]

[0096] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0097] Most preferably, the lithium aluminosilicate glass of the present invention comprises the following components in the amounts (wt%) indicated: [Table 12]

[0098] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0099] In one embodiment, the ultra-thin flexible glass is a borosilicate glass containing the following components in the amounts (by weight %) indicated: [Table 13]

[0100] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0101] The borosilicate glass of the present invention preferably comprises the following components in the amounts (% by weight) indicated: [Table 14]

[0102] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0103] The borosilicate glass of the present invention preferably comprises the following components in the amounts (% by weight) indicated: [Table 15]

[0104] Optionally, coloring oxides such as Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, and Cr2O3 can be added. 0-2% by weight of As2O3, Sb2O3, SnO2, SO3, Cl, and / or F can also be added as fining agents. 0-5% by weight of rare earth oxides can also be added to impart magnetic, photonic, or optical functionality to the glass sheet.

[0105] Typically, ultra-thin glass according to the present invention can be produced by grinding or etching from a thicker glass. These two methods are not economical in some circumstances and may require additional processing, e.g., R a This results in a reduction in surface quality, quantified by roughness. Nevertheless, the thinner surface may be sufficient for certain applications.

[0106] Direct hot forming manufacturing, such as the downdraw method and the overflow fusion method, is preferred for mass production. The redraw method is also advantageous. These mentioned methods are economical, the glass surface quality is high, and ultra-thin glass with thicknesses from 5 μm (or less) to 500 μm can be produced. For example, the downdraw / overflow fusion method allows for roughness R of less than 5 nm, preferably less than 2 nm, or even less than 1 nm. a It can be produced with an untreated or flame-finished surface. Thickness can also be precisely controlled within the range of 5 μm to 500 μm. The thin thickness gives the glass flexibility. Special float processes can produce ultra-thin glass with a pristine surface, which is economical and suitable for mass production. However, the glass produced by float processes has one side as a tin surface, which is different from the other side. The difference between the two sides can cause warping problems after chemical strengthening, and the different surface energies of the two sides affect printing or coating processes. Another variation of UTG is by cutting ultra-thin glass articles from thick glass ingots, rods, or blocks.

[0107] Strengthening, also known as tempering, can be achieved by immersing the glass in a molten salt bath containing potassium ions or by coating the glass with a paste containing potassium or other alkali metal ions and then heating it at high temperatures for a specific period of time. The alkali metal ions with larger ionic radii in the salt bath or paste are exchanged for the alkali metal ions with smaller radii in the glass article, creating surface compressive stresses due to the ion exchange.

[0108] The chemically strengthened glass article of the present invention is obtained by chemically strengthening a chemically strengthenable glass article. The strengthening process can be carried out by immersing the ultra-thin glass article in a salt bath containing monovalent ions to exchange the alkali ions within the glass. The monovalent ions in the salt bath have a larger radius than the alkali ions within the glass. Compressive stress in the glass is created after ion exchange due to the larger ions intercalating into the glass network. After ion exchange, the strength and flexibility of the ultra-thin glass are surprisingly significantly improved. Furthermore, the CS produced by chemical strengthening can improve the bending properties of the strengthened glass article and increase the scratch resistance of the glass.

[0109] The most commonly used salt for chemical strengthening is Na + containing molten salt or K + The chemical strengthening agent may be a molten salt containing Ag, NaCl, KCl, KSO, NaSO, NaCO, and KCO. Additives such as NaOH, KOH, and other sodium or potassium salts may also be used to better control the rate of ion exchange, CS, and DoL during chemical strengthening. + Contains Cu 2+ Containing salt baths can be used to impart antibacterial functionality to ultra-thin glass.

[0110] Chemical strengthening is not limited to one step. It can include multiple steps in a salt bath with various concentrations of alkali metal ions to achieve better strengthening performance. Therefore, the chemically strengthened glass article according to the present invention can be strengthened in one step or multiple steps, for example, in two steps.

[0111] A chemically strengthened glass article according to the present invention may have only one surface (first surface) in which there is a compressive stress region extending from the first surface to a first depth within the glass article, said region being defined by a compressive stress. In this case, the glass article has only one strengthened side. Preferably, the glass article according to the present invention also includes a second surface (opposite the first surface) in which there is a second compressive stress region extending from the second surface to a second depth (DoL) within the glass article, said region being defined by a compressive stress (CS), and the surface compressive stress (CS) at the second surface is at least 100 MPa. This preferred glass article is strengthened on both sides.

[0112] In a preferred embodiment of the present invention, the surface modification after chemical strengthening can be performed by etching with an acidic solution, for example, one or more of the following aqueous solutions of acids: HF, H2SO4, HCl, HNO3, and NH4HF2. These acidic solutions can be further combined with solutions with a pH of <7. The concentration of hydrogen ions in the acidic solution can be less than 25 mol / L, preferably less than 5 mol / L, more preferably less than 1 mol / L, and most preferably less than 0.1 mol / L. These etching conditions have proven particularly advantageous for the glass compositions described below. It will soon become apparent that these etching conditions can also be applied to other glass types, or that other etching conditions may also be advantageous, depending on specific requirements. In an alternative preferred embodiment of the present invention, the surface modification can also be performed by etching with an alkaline solution, for example, one or more of the following aqueous solutions of alkalis: LiOH, NaOH, and KOH. The concentration of OH ions in the alkaline solution can be less than 25 mol / L, preferably less than 20 mol / L, more preferably less than 15 mol / L, and most preferably less than 10 mol / L.

[0113] The compressive stress (CS) mainly depends on the glass composition. A higher Al2O3 content is beneficial for achieving a higher compressive stress. To achieve a balanced glass hot forming ability and chemical strengthening performance, the surface compressive stress is preferably less than 2000 MPa, preferably less than 1200 MPa. After strengthening, ultra-thin glass must have a sufficiently high compressive stress to achieve high strength. Therefore, preferably, the compressive stress of the first surface and / or second surface is 100 MPa or more, preferably 200 MPa or more, more preferably 300 MPa or more, also preferably 400 MPa or more, and even more preferably 500 MPa or more. In a particularly preferred embodiment, the surface compressive stress is 600 MPa or more, more preferably 700 MPa or more, and even more preferably 800 MPa or more.

[0114] Generally, the DoL depends on the glass composition, but it can increase almost infinitely with increasing tempering time and temperature. A defined DoL is essential to ensure stable strength of tempered glass, but too high a DoL increases the self-destruction rate and strength performance of ultra-thin glass articles under compressive stress, so the DoL should be controlled.

[0115] According to advantageous embodiments of the present invention, the tempered glass article has a CT of 1000 MPa or less, more preferably 700 MPa or less, more preferably 300 MPa or less, and more preferably 100 MPa or less. Some advantageous embodiments can have a CT of 65 MPa or less. Other advantageous embodiments can have a CT of 45 MPa or less. In some variations, even a CT of 25 MPa or less.

[0116] As mentioned above, CS, DoL and CT depend on the glass composition (type of glass), glass thickness and tempering conditions.

[0117] The inventors have found that for UTG aluminosilicate glasses, the following features are advantageous: 1. A chemically strengthened and then surface-etched glass article having a thickness (t) of less than 0.4 mm, having a first surface and a second surface, and having a compressive stress region extending from the first surface to a first depth (DoL) within the glass article, the region being defined by a compressive stress (CS), the surface CS of the first surface being at least 450 MPa; the glass article has a breaking height (given in mm) of at least 200, preferably 300, times the thickness (t in mm) of the glass article, this breaking height being determined by the pen drop test described above; the glass article has a breaking bending radius (given in mm) of <100000 × t / CS, preferably <80000 × t / CS, more preferably <70000 × t / CS, even more preferably <60000 × T / CS, where the thickness t is given in mm and CS is the numerical value of the surface compressive stress (given in MPa) measured on the first surface.

[0118] Preferably, for aluminosilicate glasses, the surface Cs of the first and / or second surface of the glass article may be 450 MPa or more, preferably 500 MPa or more, preferably 550 MPa or more, preferably 600 MPa or more, hi some advantageous embodiments, the surface Cs may be 700 MPa or more, more preferably 800 MPa or more.

[0119] In the case of UTG lithium aluminosilicate glass, the following features are advantageous: 1. A chemically strengthened and then surface-etched glass article having a thickness (t) of less than 0.4 mm, having a first surface and a second surface, and having a compressive stress region extending from the first surface to a first depth (DoL) within the glass article, the region being defined by a compressive stress (CS), the surface CS of the first surface being at least 350 MPa; the glass article has a breaking height (given in mm) of at least 200, preferably 300, times the thickness (t in mm) of the glass article, this breaking height being determined by the pen drop test described above; the glass article has a breaking bending radius (given in mm) of <100000 × t / CS, preferably <80000 × t / CS, more preferably <70000 × t / CS, even more preferably <60000 × T / CS, where the thickness t is given in mm and CS is the numerical value of the surface compressive stress (given in MPa) measured on the first surface.

[0120] Preferably, the surface C of the lithium aluminosilicate glass at the first surface and / or second surface of the glass article may be 350 MPa or more, 500 MPa or more, 600 MPa or more, preferably 700 MPa or more, more preferably 800 MPa or more.

[0121] In the case of UTG borosilicate glass, the following features are advantageous: 1. A chemically strengthened and then surface-etched glass article having a thickness (t) of less than 0.4 mm, having a first surface and a second surface, and having a compressive stress region extending from the first surface to a first depth (DoL) within the glass article, the region being defined by a compressive stress (CS), the surface CS of the first surface being at least 100 MPa; the glass article has a breaking height (given in mm) of at least 200, preferably 300, times the thickness (t in mm) of the glass article, this breaking height being determined by the pen drop test described above; the glass article has a breaking bending radius (given in mm) of <100000 × t / CS, preferably <80000 × t / CS, more preferably <70000 × t / CS, even more preferably <60000 × T / CS, where the thickness t is given in mm and CS is the numerical value of the surface compressive stress (given in MPa) measured on the first surface.

[0122] Preferably, the surface CS at the first surface and / or the second surface of the borosilicate glass may be 100 MPa or more, preferably 200 MPa or more, more preferably 300 MPa or more.

[0123] In the case of UTG soda-lime glass, the following features are advantageous: 1. A chemically strengthened and then surface-etched glass article having a thickness (t) of less than 0.4 mm, having a first surface and a second surface, and having a compressive stress region extending from the first surface to a first depth (DoL) within the glass article, the region being defined by a compressive stress (CS) of the first surface that is at least 200 MPa at the first surface, the glass article has a breaking height (given in mm) of at least 200, preferably 300, times the thickness (t in mm) of the glass article, this breaking height being determined by the pen drop test described above; the glass article has a breaking bending radius (given in mm) of <100000 × t / CS, preferably <80000 × t / CS, more preferably <70000 × t / CS, even more preferably <60000 × T / CS, where the thickness t is given in units and CS is the numerical value of the surface compressive stress (given in MPa) measured on the first surface.

[0124] Preferably, the surface CS at the first surface and / or the second surface of the soda lime glass may be 200 MPa or more, preferably 300 MPa or more.

[0125] The glass article can be advantageously used in the fields of covers and substrates for flexible and foldable electronic products, such as image sensors, display covers, and screen protectors. It can also be used in the following application areas: display substrates or protective covers, fingerprint sensor covers, general sensor substrates or covers, consumer electronics cover glass, and protective covers for displays and other surfaces, especially curved surfaces. Furthermore, the glass article can also be used in applications such as display substrates and covers, fragile sensors, fingerprint sensor module substrates or covers, semiconductor packaging, thin-film battery substrates and covers, foldable displays, and camera lens covers. In certain embodiments, the glass article can be used as a cover film for resistive screens and disposable protective films for display screens, mobile phones, foldable / flexible phones, cameras, gaming gadgets, tablets, laptops, TVs, mirrors, windows, aircraft windows, furniture, and white goods.

[0126] The present invention is particularly suitable for use in flexible electronic devices (e.g., curved displays, wearable devices) that offer thin, lightweight, and flexible properties. Such flexible devices also require flexible substrates, for example, to hold or attach components. In addition, flexible displays with high contact resistance and small bending radii are also possible.

[0127] According to the present invention, a) preparing a raw material composition for the desired glass; b) melting the composition; c) producing glass articles in a flat glass process; d) chemically strengthening the glass article; e) etching the surface of the glass article; and f) optionally coating at least one surface of the article with a coating layer; The method for producing the glass article of the present invention comprises: Also the method, wherein the etching step comprises an acid or alkaline etching that reduces the thickness of the glass article at the first surface by preferably ≦0.005 mm, preferably ≦0.004 mm, preferably ≦0.003 mm, preferably ≦0.002 mm, more preferably ≦0.001 mm, and / or ≧0.0002 mm. This etching after the strengthening step is described in detail above.

[0128] Preferably, the glass sheet process is a downdraw or redraw process, which in an advantageous variant may also be a chemical thinning process.

[0129] Advantageously, the chemical strengthening process comprises an ion exchange process. In mass production, it is advantageous if the ion exchange process comprises immersing the glass article or a portion of the glass article in a salt bath containing monovalent cations. Preferably, the monovalent cations are potassium and / or sodium ions.

[0130] Furthermore, it is advantageous if the glass article or part of the glass article is immersed in a salt bath at a temperature between 340°C and 480°C for a period of between 30 seconds and 48 hours.

[0131] For some glass types, it may be preferred that chemical strengthening comprises two successive strengthening steps, the first step comprising strengthening with a first strengthening agent and the second step comprising strengthening with a second strengthening agent. Preferably, the first and second strengthening agents comprise or consist of KNO3 and / or NaNO3 and / or mixtures thereof.

[0132] Further details of the manufacturing and strengthening procedures have already been described above. [Brief explanation of the drawings]

[0133] [Figure 1] FIG. 1 is a simplified diagram of a pen drop test. [Figure 2]FIG. 1 is a graph showing the average pen drop height (breaking height) of comparative examples and examples of the present invention for different glass types. [Figure 3] FIG. 1 is a diagram of B10 pen drop height (breaking height) for comparative examples and examples of the present invention with different glass types.

[0134] Example Table 1 shows the compositions of some typical embodiments (Types 1-5) of chemically strengthenable, direct hot-formed, ultra-thin glass.

[0135] [Table 16]

[0136] Glass articles 1 of different glass types were manufactured and chemically strengthened using a downdraw process to form chemically strengthened, ultra-thin glass articles. Each ultra-thin glass article has a first surface 2 and a second surface 3. In the illustrated embodiment, each sample representing a glass article is strengthened on both sides. As such, a compressive stress region exists on both sides of the glass article at a specific depth of length (DoL). All samples were cut from a larger glass article using a diamond cutting wheel. For the examples of the present invention, the samples were tested with surface etching.

[0137] The impact resistance of the comparative examples and examples of the present invention was tested using the pen drop test described in detail above. A simplified diagram of this test is shown in Figure 1. As shown, a glass article 1 is placed on its second surface on a 100 μm substrate 4 composed of a 50 μm thick PE layer 5 and a 50 μm thick PSA layer 6. The substrate 4 with the glass article 1 attached is placed on a rigid support 7. The first surface 2 of the glass article 1 is facing upward and is impacted until fracture with a 4.5 g pen 8 with a 300 μm diameter tungsten carbide ballpoint tip. The pen drop height is increased in steps until the glass article 1 fractures. The pen drop test is performed on small samples measuring 20 mm x 50 mm.

[0138] The fracture bend radii of the comparative examples and the inventive examples were tested using the two-point bending method described above. The bending tests were performed on small samples measuring 20 mm x 70 mm.

[0139] Comparative Example - Glass Types 1 to 5 A number of glass types 1 to 5 were prepared and chemically strengthened. These samples were 50 mm long, 20 mm wide, and 70 mm long, 20 mm wide, with thicknesses of 0.05, 0.07, 0.1, and 0.145 mm. After ion exchange, the strengthened samples were washed and measured using the FSM6000.

[0140] Thirty reinforced samples of each thickness and each DoL were tested and evaluated for impact resistance using the pen drop test described above. The average break height was calculated as described above, and the B10 height was calculated using the Weibull method.

[0141] Additionally, 30 reinforced samples of each thickness and DoL were tested using the two-point bending method described above to determine the fracture bend radius. The average fracture bend radius was calculated as described above.

[0142] Table 2 shows the test results for pen drop resistance and bend radius for Comparative Examples A-F (mean values ​​and B10 values ​​calculated using the Weibull method). Figure 2 shows the pen drop test results (mean break height) for Comparative Examples A-F. The vertical lines indicate the spread of measurements around the corresponding mean value (x) in each case. Figure 3 shows the calculated B10 heights for Comparative Examples A-F.

[0143] [Table 17]

[0144] Embodiment 1 - Glass Type 1: A number of glass type 1 samples, measuring 50 mm long and 20 mm wide, and 70 mm long and 20 mm wide, with thicknesses of 0.05 and 0.07 mm, were prepared and chemically strengthened. Different etching conditions (Table 3) were employed. After ion exchange and etching, the samples were washed and measured using the FSM6000.

[0145] Thirty reinforced samples of each thickness and DoL were tested and evaluated for impact resistance using the pen drop test described above. Table 3 shows the average pen drop height (=mean break height, in "mm") that can be applied before the glass sample breaks depending on the etching conditions. Additionally, the calculated B10 (mm) is shown. Figure 2 shows the average break height (pen drop test results) for samples with thicknesses of 0.05 mm and 0.07 mm. The vertical lines indicate the spread of measurements around the corresponding mean value (x) for each case. Figure 3 shows the calculated B10 height (pen drop test) for Examples 1 to 7 of the present invention.

[0146] Additionally, 20 tempered samples of each thickness and each DoL were tested using the two-point bend method described above to determine the average bending radius at failure, and evaluated as described above. Because the samples were measured as cut (i.e., without edge treatment), glass articles with treated edges would have an even smaller bending radius.

[0147] [Table 18]

[0148] Comparing Inventive Examples (hereinafter simply referred to as "Examples") 1-7 with each other and with Comparative Examples A and B, the following can be seen: The examples of glass type 1 that were chemically strengthened and then etched primarily demonstrate an increase in pen drop height compared to comparative examples of the same glass type without etching. The pen drop height can be increased by more than 30% up to more than 100%. For example, the pen drop height of Example 1, which has a thickness of 0.05 mm, is approximately 40% higher than that of Comparative Example A, which has the same thickness, and the pen drop height of Example 4, which has a thickness of 0.07 mm, is approximately 55% higher than that of Comparative Example B, which has the same thickness. Example 6 further demonstrates an increase in pen drop height of more than 100%.

[0149] For etched samples of the same glass type, the achievable pen drop height depends on the etching medium applied: for a 0.07 mm thick glass (glass type 1), the best results are obtained using a mixture of NH4HF2 and HNO3 (Example 6).

[0150] Furthermore, the resulting pen drop height within the use of one particular etching medium depends on the applied etching conditions (time, temperature, concentration). If the conditions are insufficient, the pen drop height of the etched glass will deteriorate, as can be seen by comparing Example 1 with Example 2, or Examples 3 and 5 with each other. Here, a lower concentration of the etching medium appears to give better results in terms of pen drop height. In the worst case, the pen drop height of the etched tempered glass may even be lower than that of the unetched glass (e.g., Example 2 compared to Comparative Example A).

[0151] Other aluminosilicate glasses, such as a glass containing (by weight): about 62% SiO, 20% AlO, 4% BO, 13% NaO, 1% MgO, or a glass containing (by weight): about 56% SiO, 24% AlO, 1% BO, 3% LiO, 10% NaO, 1% ZnO, 5% PO, can show similar results when produced and tested under corresponding conditions.

[0152] Embodiment 2 - Glass Type 2 A number of glass type 2 samples, each measuring 50 mm long, 20 mm wide, and 70 mm long, 20 mm wide, and 0.07 mm thick, were prepared and chemically strengthened. Different etching conditions (Table 4) were employed. Example 7 was strengthened in one step, while Examples 8 and 9 were strengthened in two steps. After ion exchange and etching, the samples were washed and measured using an FSM6000.

[0153] Thirty reinforced samples of each thickness and DoL were tested and evaluated for impact resistance using the pen drop test described above. Table 4 shows the average pen drop height (=average break height, in "mm") that a glass sample could be subjected to before breaking under different etching conditions. The break bend radius was measured using the two-point bending method described above. In each test / experiment, multiple samples of 30 samples of each thickness and type of DoL were tested and evaluated as described above. Table 4 shows the sample conditions and experimental results.

[0154] [Table 19]

[0155] As can be seen from a comparison of Example 8, Example 9, and Comparative Example C, the etching treatment can increase the pen drop height by more than about 80% (Example 9). Example 8 has an even higher increase in pen drop height. However, if improper etching conditions are used, the pen drop height can be even lower compared to the unetched sample (see Example 10 compared to Comparative Example C).

[0156] Embodiment 3 - Glass Type 3 A number of glass type 3 samples, measuring 50 mm long, 20 mm wide, and 70 mm long, 20 mm wide, and 0.07 mm thick, were prepared and chemically strengthened. Different etching conditions (Table 5) were employed. After ion exchange and etching, the samples were cleaned and measured using the FSM6000. Impact resistance was tested using the pen drop test detailed above. Additionally, the fracture bend radius was measured using the two-point bending method described above. For each test / experiment, multiple samples (30 samples) of each DoL were tested and evaluated as described above. Table 5 shows the sample conditions and experimental results.

[0157] [Table 20]

[0158] As can be seen by comparing Examples 11, 12, and 13 with Comparative Example D, the pen drop height can be increased by more than about 40% (Example 13) and at least 70% (Example 11) by etching. Example 12 has an even higher increase in pen drop height. By using the same etching medium and appropriately selecting the etching conditions, the pen drop height can be improved.

[0159] Embodiment 4 - Glass Type 4 A number of glass type 4 samples, measuring 50 mm long, 20 mm wide, and 70 mm long, 20 mm wide, and 0.1 mm thick, were prepared and chemically strengthened. Different etching conditions (Table 6) were employed. After ion exchange and etching, the samples were cleaned and measured using the FSM6000. Impact resistance was tested using the pen drop test detailed above. Additionally, the fracture bend radius was measured using the two-point bending method described above. For each test / experiment, multiple samples (20 samples) of each DoL were tested and evaluated as described above. Table 6 shows the sample conditions and experimental results.

[0160] [Table 21]

[0161] As can be seen by comparing Examples 14, 15, and 16 with Comparative Example E, the pen drop height can be increased by more than about 35% (Example 16) and more than 90% (Example 14) by etching. Example 15 has an even higher increase in pen drop height (more than 110%). By using the same etching medium and appropriately selecting the etching conditions, the pen drop height can be improved.

[0162] Embodiment 5 - Glass Type 5 A number of glass type 5 samples, measuring 50 mm long, 20 mm wide, and 70 mm long, 20 mm wide, and 0.145 mm thick, were prepared and chemically strengthened. Different etching conditions (Table 7) were employed. After ion exchange and etching, the samples were cleaned and measured using the FSM6000. Impact resistance was tested using the pen drop test detailed above. Additionally, the fracture bend radius was measured using the two-point bending method described above. For each test / experiment, multiple samples (20 samples) of each DoL were tested and evaluated as described above. Table 7 shows the sample conditions and experimental results.

[0163] [Table 22]

[0164] Comparing Examples 18 and 19 with Comparative Example F, it can be seen that the pen drop height can be increased by more than about 55% (Example 19) and more than 65% (Example 18) by etching. However, Example 17 has a relatively small increase in pen drop height. This indicates that proper selection of etching conditions using the same etching medium is necessary to optimize the pen drop height.

[0165] Typically, the strength of chemically strengthened, etched, ultra-thin glass articles according to the present invention, as determined by pen drop testing, follows a Weibull distribution. The B10 value, which defines the height at which 10% of the samples break, is shown in the figure.

[0166] It can be seen from Examples 1-5 that ultra-thin glass articles of various glass types that are chemically strengthened and then etched have improved impact resistance, overall flexibility, and reliability (even in the absence of an additional coating / polymer layer on the first surface of the glass article that may come into contact with a hard object) compared to glass articles that are only chemically strengthened.

[0167] Embodiment 6 - Glass Type 1 A number of glass type 1 samples were cut, chemically strengthened, and then etched, measuring 50 mm long, 20 mm wide, and 70 mm long, 20 mm wide, with thicknesses of 0.05 mm and 0.07 mm. After ion exchange and etching, the samples were cleaned and measured with an FSM6000. Different coated layers (polymer layer and / or hard coating layer) were laminated / coated on the first surface (top coating) (Table 8). Some examples were also prepared with coated layers on both the first and second surfaces (see Example 27). Different coated layer types with different thicknesses were applied to the glass articles by different methods: Glass articles were coated with a liquid polyimide (PI) material by a bar coating method and then solidified for Examples 22, 24, and 28. After coating the first surface with the PI material, a 20 μm hard coating layer (epoxy-siloxane hybrid material) was deposited on top of the PI material layer using a roll-to-roll coating method to produce Example 28.

[0168] Example 20 was laminated with a polyethylene (PE) material using a commercially available laminating machine.

[0169] Example 21 was laminated with a commercially available polyethylene terephthalate (PET) material using a commercially available laminating machine.

[0170] Examples 23 and 25 were laminated with a commercially available thermoplastic polyurethane (TPU) material using a commercially available laminating machine.

[0171] Examples 26 and 27 were prepared as follows: a 20 μm hard coating layer (epoxy-siloxane hybrid material) was applied to a first surface of a glass article using a known roll-to-roll coating method. Additionally, in Example 27, another 20 μm hard coating layer (epoxy-siloxane hybrid material) was applied to a second surface of the glass article using a known roll-to-roll coating method. Thus, Example 27 has both a top coating and a bottom coating.

[0172] Comparative Examples G and H (glass type 1) were prepared and measured corresponding to Examples 26 and 28, but without the subsequent etching step after chemical strengthening.

[0173] Using the pen drop test detailed above, 30 reinforced samples of each thickness and coating layer type were tested and evaluated for impact resistance. The coated first surface was impacted with a pen. To perform the impact test of Example 27, the hard coating on the second surface of the glass article was placed on a 100 μm thick substrate. Table 7 shows the average pen drop height (= average break height, in "mm") that could be applied until the glass sample broke for different polymer layers and hard coating layers. Additionally, the calculated B10 (mm) is shown. [Table 23] [Table 24]

[0174] Comparing the coated example of Example 6 (Glass Type 1) with Examples 1-7 (Glass Type 1) of comparable thickness shows that the coated layer can significantly increase the pen drop height (at least 50%). Both the polymer layer and the hard coating layer improve impact resistance. Adding a bottom coating in addition to the top coating can further improve impact resistance (see Examples 26 and 27). Adding a hard coating layer on top of the polymer top coating can further improve impact resistance (see Examples 28 and 24). Comparisons of Comparative Example G and Example 26 and Comparative Example H and Example 28 show that etching treatment after chemical strengthening improves the impact resistance of coated ultrathin glass articles. Furthermore, the coated polymer layer and hard coating layer can protect the glass article from external scratches, which can improve the reliability of the glass cover. The coated layer may also be beneficial for other UTGs with other glass types.

Claims

1. 1. A glass article (1) having a thickness (t) of less than 0.3 mm, the glass article (1) having a first surface (2), a second surface (3), and a compressive stress region extending from the first surface to a first depth (DoL) within the glass article, the region being defined by a compressive stress (CS), the surface compressive stress (CS) at the first surface (2) being at least 100 MPa; - the glass article (1) has a breaking height (given in mm) of at least 200 times the thickness (t (mm)) of the glass article, the breaking height being determined by a pen drop test in which the glass article (1) is attached with its second surface (3) to a 100 μm thick substrate (4) consisting of a 50 μm thick layer (5) of polyethylene (PE) material and a 50 μm thick layer (6) of pressure-sensitive adhesive (PSA) material, the second surface (3) being in contact with the PSA layer (6), the substrate (4) to which the glass article (1) is attached being placed on a rigid support (7) and impacted, with the first surface (2) of the glass article (1) facing upwards, with a 4.5 g pen (8) having a 300 μm diameter tungsten carbide ball point tip until breaking; - the glass article (1) has a fracture bending radius (given in mm) that is smaller than the thickness (t (mm)) of the article multiplied by 100,000 and divided by the surface compressive stress (MPa) measured on the first surface, and the glass article has at least 1% by weight and at most 2% by weight of K 2 A glass article (1) comprising O.

2. 2. The glass article of claim 1, wherein the glass article (1) has a breaking height (given in mm) of at least 300 times the thickness (t in mm) of the glass article.

3. 3. The glass article of claim 1 or 2, wherein the glass article (1) has a B10 breaking height (given in mm) of at least 150 times the thickness (t (mm)) of the glass article.

4. 4. The glass article of any one of claims 1 to 3, wherein the glass article (1) has a thickness of ≦0.33 mm and ≧0.005 mm.

5. 5. The glass article of any one of claims 1 to 4, wherein the glass article (1) has a modified first surface (2) produced by etching away.

6. 6. The glass article of any one of claims 1 to 5, wherein the glass article (1) has a pen drop height increased by > 20% compared to a corresponding chemically strengthened and unetched glass article.

7. 7. The glass article of any one of claims 1 to 6, wherein the glass article (1) has a central tensile stress (CT) of 2 MPa or more.

8. 8. The glass article of any one of claims 1 to 7, wherein the glass article (1) comprises a coated layer on at least one surface comprising a coating material.

9. The glass article (1) comprises a coated layer on the first surface, the coated layer comprising: ２ Thickness t≦(0.3−t) ２ 9. The glass article of claim 8, wherein the coated glass article has a breaking height of at least 500 times the thickness of the uncoated glass article, the breaking height being determined by a pen drop test in which the glass article (1) is attached by its second surface (3) to a 100 μm thick substrate (4) consisting of a 50 μm thick layer of polyethylene (PE) material (5) and a 50 μm thick layer of pressure-sensitive adhesive (PSA) material (6), the second surface (3) being in contact with the PSA layer (6), the substrate (4) with the attached glass article (1) placed on a rigid support (7), and with the first surface (2) of the glass article (1) facing upwards, the coated layer is impacted with a 4.5 g pen (8) having a 300 μm diameter tungsten carbide ballpoint tip until the glass article breaks.

10. 10. The glass article of claim 8 or 9, wherein the glass article (1) comprises or is incorporated between polymer layers, the polymer layers being selected from the group consisting of silicone polymers, polycarbonate (PC), polyethersulfone, polyacrylate, polyimide (PI), cycloolefin copolymers, polyolefins, silicone resins, polyethylene (PE), polypropylene, polypropylene polyvinyl chloride, polystyrene, styrene-acrylonitrile copolymers, thermoplastic polyurethane resins (TPU), polymethyl methacrylate (PMMA), ethylene-vinyl acetate copolymers, polyethylene terephthalate (PET), polybutylene terephthalate, polyamide (PA), polyacetal, polyphenylene oxide, polyphenylene sulfide, fluorinated polymers, chlorinated polymers, ethylene-tetrafluoroethylene (ETFE), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF), polyethylene naphthalate (PEN), and mixtures thereof.

11. 11. The glass article of any one of claims 8 to 10, wherein the coated layer comprises a coating material selected from the group consisting of thermosetting reactive resins, phenoplasts, phenol formaldehyde resins, aminoplasts, urea formaldehyde resins, melamine formaldehyde resins, epoxide resins, unsaturated polyester resins, vinyl ester resins, phenacrylate resins, diallyl phthalate resins, silicone resins, crosslinked polyurethane resins, polymethacrylate reactive resins, polyacrylate reactive resins, and acrylic resins.

12. 12. A glass article according to any one of claims 1 to 11, wherein at least one edge of the glass article (1) is covered with at least one coating layer.

13. 13. The glass article of any one of claims 1 to 12, wherein the glass article (1) has a second compressive stress region extending from the second surface (3) to a second depth (DoL) within the glass article, the region being defined by a compressive stress (CS), the surface compressive stress at the second surface (3) being at least 100 MPa, and the second surface (3) being a modified surface produced by etching away.

14. 14. The glass article of any one of claims 1 to 13, wherein the compressive stress (CS) at the first surface (2) of the glass article (1) is greater than 100 MPa.

15. 15. The glass article of any one of claims 1 to 14, wherein the glass comprises the following components in the indicated amounts (by weight): Table 1

16. 15. The glass article of any one of claims 1 to 14, wherein the glass comprises the following components in the indicated amounts (by weight): Table 2

17. 15. The glass article of any one of claims 1 to 14, wherein the glass comprises the following components in the indicated amounts (by weight): Table 3

18. 18. Use of the glass article of any one of claims 1 to 17 as a cover film for resistive screens and disposable protective films for display screens, foldable / flexible phones, cameras, gaming gadgets, tablets, laptops, TVs, mirrors, windows, aircraft windows, furniture, and white goods.

19. 18. Use of the glass article of any one of claims 1 to 17 in the applications of display substrates and covers, fragile sensors, fingerprint sensor module substrates or covers, semiconductor packaging, thin film battery substrates and covers, foldable displays, camera lens covers.

20. a) preparing a raw material composition for the desired glass; b) melting the composition; c) producing glass articles in a flat glass process; d) chemically strengthening the glass article; e) etching the surface of the glass article; and f) optionally coating at least one surface of the glass article with a coating layer; A method for producing a glass article according to any one of claims 1 to 17, comprising: The method, wherein the etching step comprises an acid or alkaline etching that reduces the thickness of the glass article (1) at the first surface (2) by ≦0.005 mm and ≧0.0002 mm.

21. 21. The method of claim 20, wherein the sheet glass process is a downdraw or redraw or overflow fusion process.

22. 22. The method of claim 20 or 21, wherein the chemical strengthening step comprises an ion exchange process comprising immersing the glass article or a portion of the glass article in a salt bath containing monovalent cations.

23. 23. The method of claim 22, wherein the monovalent cation is potassium ion and / or sodium ion.

24. 24. The method according to claim 22 or 23, wherein the glass article (1) or a part of the glass article (1) is immersed in a salt bath at a temperature of 340°C to 480°C for a period of 30 seconds to 48 hours.

25. 25. The method of any one of claims 20 to 24, wherein the chemical strengthening comprises two successive strengthening steps, the first step comprising strengthening with a first toughening agent and the second step comprising strengthening with a second toughening agent.

26. The first toughening agent and the second toughening agent are KNO ３ , NaNO ３ 26. The method of claim 25, comprising or consisting of: and / or mixtures thereof.

27. The acid is HF, H ２ SO ４ , HNO ３ , HCl, NH ４ HF ２ 27. The method of any one of claims 20 to 26, wherein the at least one selected from the group consisting of: and organic acids.

28. The alkali is LiOH, NaOH, KOH, and NH ４ 27. The method of any one of claims 20 to 26, wherein the alkyl group is at least one selected from the group consisting of OH.

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