Glass or glass-ceramic sheet comprising at least one coating applied to at least one area of ​​at least one side of the glass or glass-ceramic sheet and glass-ceramic material for coating such a glass or glass-ceramic sheet, composite comprising such a sheet and its use

Abstract

The present invention relates to a glass-ceramic material for coating a glass or glass-ceramic disc and to the disc coated with the material. It has high optical density, high fracture strength, and high flexural strength.

Description

Field of invention

[0001] The present invention relates generally to glass or glass-ceramic sheets, in particular to glass or glass-ceramic sheets which have a coating in at least one region of at least one side of the glass or glass-ceramic sheet. The invention further relates, according to a further aspect, to a glass-ceramic material for coating such a glass or glass-ceramic sheet, to a composite comprising such a glass or glass-ceramic sheet, and its use. Background of the invention

[0002] Glass panes made of or comprising borosilicate glass, especially those that are at least partially coated, have been known for a long time and are used, for example, as oven viewing windows in oven doors. The advantages of borosilicate glass here are its thermal resistance compared to conventional soda-lime glass, which is why, for example, oven viewing windows for pyrolytic ovens often consist of such borosilicate glass panes.

[0003] However, borosilicate glasses can also be advantageous for other applications, as they offer inherent advantages over conventional soda-lime glasses, for example, in terms of scratch resistance, general mechanical strength, and chemical resistance. Therefore, borosilicate glass panes are increasingly being used in windshields.

[0004] It is well known that borosilicate glass, such as that commercially available under the trade name Borofloat®, is used in the exterior glazing of vehicles. This type of glass is particularly well-suited for laminated glazing and is characterized by very high transmission in the visible light range. Furthermore, borosilicate glass offers excellent heat resistance, high chemical resistance, and good mechanical strength.

[0005] Glass-ceramic panels offer several advantages over glass panels: They exhibit high temperature resistance and can withstand large temperature fluctuations without breaking or deforming. Therefore, glass-ceramic panels are used, for example, as cooktops or (fireplace) stove glazing. They are also used in laminated glazing, such as safety glazing for mobile applications, e.g., in vehicles, or static applications, e.g., in architecture.

[0006] Windshields are designed as laminated glass for the safety of vehicle occupants and typically have a coating at the edges. This coating serves two purposes: firstly, to visually conceal adhesives or components such as antennas, and secondly, to protect them from UV radiation. This coating is usually located between the two glass panes of the laminate. The laminate also includes a polymeric layer between the two glass panes, bonding them together. The glass panes, with the coating applied between them in at least one area, particularly at the edges, are placed on top of each other and bent using a thermal forming process.Subsequently, a polymer layer is placed between the two panes and the curved glass panes are joined together, so that finally a laminated glass pane (which is also simply referred to as a "laminate" within the scope of the present disclosure) is obtained.

[0007] For example, oven windows often have a coating at the edges to limit the view into the interior.

[0008] A number of requirements are therefore placed on the glass or glass-ceramic panes and their coatings used for these applications. Since the bending processes for composite production are thermal, the glass panes and the coating applied to them must be able to withstand these temperatures. The glass panes and the coating must be able to bond with the polymer layer in such a way that a stable composite is formed and delamination between the glass and polymer does not occur. Finally, the coating must have sufficient optical density so that, for example, components located in the frame area of ​​windshields are not distractingly visible. This prevents driver distraction and thus increases driving safety. Microcracks or other defects in the coating should also be avoided or at least minimized wherever possible.

[0009] In addition to the temperature resistance of glass and coating or glass-ceramic and coating, the aforementioned compatibility of glass, glass-ceramic or coating with a polymeric material for the formation of a bond, the optical density and the minimization of possible defects, the mechanical strength, characterized for example by the fracture or bending strength, of a coated glass pane also plays a role.

[0010] EP 4166519 A1 describes glass panes with coatings containing binders, pigments, and additives, and exhibiting sufficient flexural strength. WO 2020247194 A1 describes additives for frits based on the Al2TiO5 system, but these do not achieve the desired color effects for the uses described here.

[0011] Therefore, there is still a need for improvement regarding the overall required property profile of the coating materials and ultimately also of the coating itself, namely the simultaneous presence of both sufficient fracture and flexural strength as well as sufficiently high optical density and a sufficiently dark color impression. Object of the invention

[0012] The object of the present invention is to provide glass and glass-ceramic sheets that are coated at least in certain areas, thereby at least partially mitigating the aforementioned weaknesses of the prior art. Further aspects of the invention relate to a glass-ceramic material, in particular for producing a coating on such a glass or glass-ceramic sheet, a composite comprising such a glass or glass-ceramic sheet, and its use. Summary of the invention

[0013] The object of the invention is achieved by the subject matter of the independent claims. Preferred and specific embodiments are found in the dependent claims, the description, and the drawings of this disclosure.

[0014] The invention relates to a glass-ceramic material.

[0015] The glass-ceramic material comprises a glass phase.

[0016] The proportion of the glass phase is 1 wt.% to 50 wt.%.

[0017] In some embodiments, the proportion of the glass phase is in the range of 2 wt.% to 40 wt.%, preferably in the range of 5 wt.% to < 40 wt.%. The proportion of the glass phase can then, in particular, be at least 2 wt.% or at least 5 wt.%. The proportion of the glass phase can then, in particular, be at most 40 wt.% or at most < 40 wt.%.

[0018] The glass-ceramic material comprises a crystalline phase.

[0019] The proportion of the crystalline phase is 50 wt.% to 99 wt.%.

[0020] In some embodiments, the proportion of the crystalline phase is in the range of 60 wt.% to 98 wt.%, preferably from > 40 wt.% to 95 wt.%. The proportion of the crystalline phase can then, in particular, be at least 60 wt.%, or at least > 60 wt.%. The proportion of the crystalline phase can then, in particular, be at most 98 wt.% or at most 95 wt.%.

[0021] The crystalline phase comprises or consists of at least two crystal phases. Depending on the number and proportion of the crystal phases present, they can be primary or secondary crystal phases.

[0022] One of the crystal phases, referred to as the first crystal phase, comprises crystallites of mixed crystals from the pseudobrookite system.

[0023] Pseudobrookite can be described as Fe 1+x Ti 2-x O5, where x can take values ​​between 0 and 1.

[0024] The two final compositions of this solid solution series, namely FeTi2O5 with x = 0 and Fe2TiO5 with x = 1, are called iron(II) pseudobrookite and iron(III) pseudobrookite.

[0025] In pseudobrookite solid solution, proportions of the iron ions can be replaced by other metal ions, e.g. manganese, magnesium, cobalt, zinc, nickel.

[0026] The pseudobrookit system can thus be described in general form using the following idealized formulas: Fe 1-y M y TiO3, where M is selected from the group Mn, Mg, Co, Zn, Cr, where Mn is preferred, or (Fe 1-y M y )Ti2O5, where M is selected from the group Co, Ni or (Fe 1-y M y )2TiO4, where M is selected from the group Zn, Mg and combinations of two or more of them. where y can take values ​​from 0 to 0.8. It is preferred that y > 0.

[0027] Furthermore, within the pseudobrookite system, titanium ions, preferably not more than 50%, can be replaced by chromium ions. Cr 3+ the place of Ti 3+ and Cr 4+ the place of Ti 4+ take.

[0028] Preferably, the first crystal phase consists of crystallites of pseudobrookite mixed crystals Fe 1+x Ti 2-x O5, where x can take values ​​between 0 and 1. Preferably, the pseudobrookite solid solution contains more iron(II) than iron(III).

[0029] In glass-ceramic material, in addition to the first crystal phase, at least one further crystal phase, referred to as the second crystal phase, is present in the crystalline phase.

[0030] Preferably it comprises or consists of β-spodumene and / or high-quartz solid solution and / or ilmenite solid solution and / or spinel solid solution.

[0031] If ilmenite solid solution is present, it is preferably present at a maximum of 18 wt. %.

[0032] The terms "first" and "second" crystal phase say nothing about the proportion of each crystal phase within the crystalline phase. Thus, the second crystal phase can be the main crystal phase.

[0033] β-spodumene or high-quartz solid solution or ilmenite solid solution can also be the main crystal phase.

[0034] It is preferred that β-spodumene and / or high-quartz solid solution are the main crystal phase. In such embodiments, the pseudobrookite system is a secondary crystal phase. Preferably, it is present at least 4 wt.%, more preferably at least 5 wt.%.

[0035] In some embodiments, ilmenite solid solution and / or spinel solid solution represent further secondary crystal phases.

[0036] In some embodiments, the average crystal size of the crystallites present in the crystalline phase of the glass-ceramic material is in the range of 0.06 to 5 µm, preferably in the range of 0.1 to 5 µm, and more preferably in the range of 0.5 to 1.2 µm. The average crystal size of the crystallites can, for example, be at least 0.06 µm, at least 0.1 µm, or preferably at least 0.5 µm. The average crystal size of the crystallites can, for example, be at most 5 µm, or more preferably at most 2 µm.

[0037] When crystal sizes are mentioned, the average principal diameter is meant, which results from measuring the dimensions of the crystallites in an image taken with a scanning electron microscope (SEM). For this purpose, the crystallites visible in the image are analyzed using image analysis software. The maximum extent of the crystallites is interpreted as the individual principal diameter, and then the arithmetic mean diameter is calculated from the sum of the individual principal diameters.

[0038] The glass-ceramic material has a linear coefficient of thermal expansion CTE20-300 of -2.0 * 10 -6 / K up to 4.0 * 10 -6 / K is, preferably 0 * 10 -6 / K to < 4.0 * 10 -6 / K, especially preferred 0 * 10 -6 / K to 3.5 * 10 -6 / K on.

[0039] Where reference is made to the coefficient of thermal expansion in this application, this refers to the linear coefficient of thermal expansion α. ​​Unless otherwise stated, this is specified in the range of 20-300°C. The designations α and α 20-300CTE and CTE20-300 are used synonymously within the scope of this invention. This coefficient can be determined, in particular for glassy materials, using a method according to ISO 7991. The thermal expansion coefficient of the coating is understood to be the resulting thermal expansion coefficient of the respective coating, which is derived from the thermal expansion coefficients of the individual components of the coating, taking into account their proportion of the coating. Whenever the present application refers to the thermal expansion coefficient of the glass pane, this always refers to the thermal expansion coefficient of the glassy material (or glass) of the glass pane (i.e., the substrate).

[0040] In some embodiments, the starting glass for the glass-ceramic material and / or the glass-ceramic material of the present invention contains TiO2 in a proportion of 0.03 to 40 wt.%, for example, 0.5 to 20 wt.%, 0.5 to 32 wt.%, 0.5 to 15 wt.%, or 1 to 12 wt.%. The proportion of TiO2 can then, in particular, be at least 0.03 wt.%, at least 0.5 wt.%, or at least 1.0 wt.%. The proportion of TiO2 can then, in particular, be at most 40 wt.%, at most 32 wt.%, at most 20 wt.%, at most 15 wt.%, or at most 12 wt.%.

[0041] In some embodiments, the starting glass for the glass-ceramic material and / or the glass-ceramic material of the present invention contains Fe₂O₃ in a proportion of 0.07 to 44 wt.%, for example, 0.5 to 20 wt.% or 1 to 15 wt.%. The proportion of Fe₂O₃ can then, in particular, be at least 0.07 wt.%, at least 0.5 wt.%, or at least 1 wt.%. The proportion of Fe₂O₃ can then, in particular, be at most 44 wt.%, at most 20 wt.%, or at most 15 wt.%.

[0042] In some embodiments, the starting glass for the glass-ceramic material and / or the glass-ceramic material of the present invention contains MnO2 in a proportion of 0.03 to 25 wt.%, for example, 0.5 to 15 wt.% or 1.0 to 10 wt.%. The proportion of MnO2 can then, in particular, be at least 0.03 wt.%, at least 0.5 wt.%, or at least 1 wt.%. The proportion of MnO2 can then, in particular, be at most 25 wt.%, at most 15 wt.%, or at most 10 wt.%.

[0043] In some embodiments, the starting glass and / or the glass-ceramic material of the present invention comprises the following components in the specified amounts (in weight percent on an oxide basis): component Portion SiO2 1-70 B2O3 0-7 Al2O3 0,03-25 Bi2O3 0-5 P2O5 0-5 Li2O 0-10 Na2O 0-7 K2O 0-7 MgO 0-7 CaO 0-7 SrO 0-7 ZnO 0-30 TiO2 0,03-40 ZrO2 0-5 MnO2 0,03-25 Fe2O3 0,07-44 SnO2 0-2 F 0-2 Reducing agent >0-2 Total RO 0-15 Total R2O 0-15

[0044] The term RO stands for the alkaline earth metal oxides MgO, CaO, SrO, BaO.

[0045] The term R2O stands for the alkali metal oxides Li2O, Na2O, K2O.

[0046] Sugar, for example, can be used as a reducing agent.

[0047] In some embodiments, the starting glass for the glass-ceramic material and / or the glass-ceramic material of the present invention contains the following components in the specified amounts (in weight percent on an oxide basis): component Portion SiO2 20-70, preferably 40-70 B2O3 0-7, preferably 0-3 Al2O; 0.5-15 or 10-25 Bi2O3 0-5, preferably 0-0.5 P2O5 0-5 Li2O 0-10, preferably 0-5 Na2O 0-15, preferably 0-10 K2O 0-15, preferably 0-10 MgO 0-5, preferably 0-3 CaO 0-5, preferably 0-3 SrO 0-5, preferably 0-3 ZnO 0-25, preferably 0-10 TiO2 0.5-40, preferably 0.5-35 ZrO2 0-5, preferably 0-2.5 MnO2 0,5-20 Fe2O3 0,5-38 SnO2 0-2 F 0-1 Reducing agent 0.5-2, preferably 0.5-1.5 Total RO 0-7 Total R2O 0.5-15, preferably 0-10, particularly preferably 0-7

[0048] In some embodiments, the starting glass for the glass-ceramic material and / or the glass-ceramic material of the present invention contains the following components in the specified amounts (in weight percent on an oxide basis): component Portion SiO2 17 - 65 B2O3 0-3 Al2O3 5 - 20 Bi2O3 0 - 0,5 P2O5 0-2 Li2O 0 - 3.6, preferably ≥ 2.5 Na2O 0 - <4 K2O 0 - <4 MgO 0 - 0,5 CaO 0-1 SrO 0-1 ZnO 0-5 TiO2 2,5 -30 ZrO2 0 - 1,5 MnO2 1,5 - 17 Fe2O3 2,5 -32 SnO2 0-2 F 0-1 Reducing agent 0,5-1,5 Total RO 0-5 Total R2O 0-<4

[0049] In some embodiments, the starting glass for the glass-ceramic material and / or the glass-ceramic material of the present invention contains no SrO and / or no B2O3 and / or no Bi2O3 and / or no Cl and / or no CoO and / or no Cr2O3 and / or no F and / or no P2O5 and / or no V2O5

[0050] The glass-ceramic material of the invention is obtained by ceramizing suitable starting glasses. The composition of the starting glasses is not substantially altered by the ceramization. The composition of the glass-ceramic material therefore essentially corresponds to the composition of the starting glass.

[0051] The glass-ceramic material of the invention can be produced by a process comprising the following steps: a) Provision of a starting glass, wherein the starting glass was melted under reducing conditions for 30 min to 2.5 h at 1600 °C to 1650 °C b) Melting the initial glass by thermal treatment at a temperature of more than 1050 °C to 1270 °C for a duration of 3 minutes to 12 hours, preferably from 3 minutes to 5 hours, particularly preferably from 3 minutes to 1 hour.

[0052] Step b) can optionally be preceded by a thermal treatment at 700 °C to 735 °C for a duration of 4 to 6 hours.

[0053] The step of providing a starting glass may include, in particular, melting glass raw materials under reducing conditions (especially under a reducing atmosphere) and / or quenching the melt. Quenching may include, in particular, rapid roller quenching, water or air quenching, or a combination of two or more of these methods.

[0054] The process for producing a glass-ceramic material as a filler can further include the step of grinding the glass-ceramic material. The grinding step can be carried out in such a way that the grains preferably have a grain size d50 in the range of 0.1 µm to 5 µm, from 0.5 µm to 3.0 µm, or only up to 1.5 µm. A grain size d50 of less than 1 µm is preferred.

[0055] The designation d50 for grain size is generally known in the measurement of grain size distribution and requires no further explanation here.

[0056] The glass-ceramic material according to the invention, in particular the glass-ceramic material produced by this method, has a high optical density in the VIS range, preferably OD > 40 / mm, preferably > 50 / mm, and an advantageous color appearance.

[0057] The glass-ceramic material produced using this method has a linear coefficient of thermal expansion CTE20-300 of -2 * 10 -6 / K up to 4.0 * 10 -6 / K is, preferably 0 * 10 -6 / K to < 4.0* 10 -6 / K, especially preferred between 0 * 10 -6 / K to +3.5 * 10 -6 / K on.

[0058] The invention also relates to a glass or glass-ceramic disc comprising a glass or a glass-ceramic comprising SiO2 and Al2O3 and at least one component from the group Li2O, B2O3.

[0059] The glass or glass-ceramic sheet comprises at least one coating applied to at least one region on at least one side of the sheet, with a first coating designed as an enamel layer, wherein the first coating comprises at least one glass-based binder comprising SiO2 and, as a filler, at least one of the glass-ceramic materials according to the invention, and optionally contains one or more pigments. The presence of one or more pigments is preferred.

[0060] Such a glass or glass-ceramic disc has a number of advantages.

[0061] In certain embodiments, the glass sheet preferably comprises a glass consisting of SiO2, Al2O3, and B2O3, i.e., a so-called borosilicate glass. This type of glass material (or simply glass) is a chemically very resistant material that is also mechanically resistant and, compared to conventional glasses such as soda-lime glasses, exhibits good thermal resistance and good mechanical strength even in an unstressed state. It has also been shown that the scratch resistance of such borosilicate glasses is higher than that of soda-lime glasses.

[0062] In embodiments, the glass-ceramic disc preferably comprises a glass-ceramic disc containing SiO2, Al2O3, and Li2O, i.e., a so-called LAS glass-ceramic. This type of glass-ceramic material (or simply glass-ceramic) is a thermally very resistant material that is also mechanically resistant and, compared to glasses such as soda-lime glasses, exhibits good thermal resistance and good mechanical strength even in an unstressed state.

[0063] In embodiments, the glass pane preferably comprises a glass containing SiO2, CaO and Na2O, i.e. a so-called soda-lime glass.

[0064] The coating is formed in at least one area on at least one side of the glass or glass-ceramic pane. Preferably, the coating is formed in the form of a frame over the entire edge area of ​​one side of the glass pane, and it is further possible that towards the central area of ​​the glass pane the coating is no longer opaque, but rather applied in the form of a so-called dot matrix. This can be particularly advantageous if the glass pane is used as part of a composite, for example, as a windshield.

[0065] The coating is designed to be chemically and thermally resistant. This means that the coating contains a binder comprising SiO2. SiO2 exhibits good chemical resistance and is also temperature-stable.

[0066] The coating comprises the glass-ceramic material according to the invention as a filler. All disclosed embodiments of the glass-ceramic material are hereby also disclosed for use as a filler in the coating.

[0067] The coating can contain one or more additional fillers besides the glass-ceramic material. These fillers typically have a medium grain size ranging from the nanometer to the micrometer range.

[0068] Other fillers may include, in particular: Silicas, for example pyrogenic or precipitated silicas, Quartz glass, e.g. as spherical particles, e.g. high-purity spherical quartz glass, porous fillers, for example porous glasses such as those available under the name "CoralPor®", or porous crystalline materials, In-situ generated fillers, for example through decomposition of a metal-organic or silicon-organic component.

[0069] Due to the low coefficient of thermal expansion of the glass-ceramic material of CTE20-300 between 0 * 10 -6 / K and 4.0 * 10 -6 / K, preferably 0 * 10 -6 / K to < 4.0 * 10 -6 / K, the coating can be made without other fillers that have the purpose of lowering the coefficient of expansion of the coating and adapting its expansion behavior to that of the disc.

[0070] Due to their high optical density and their color impression, describable by LAB values, the coating does not require the addition of pigments. This is advantageous because conventional pigments have a relatively high coefficient of thermal expansion, and their use would increase the coating's already low coefficient of thermal expansion, which is already low due to the glass-ceramic material used as filler. For example, the black pigment CuCr2O4 has a CTE20-300 of 10 x 10-6 / K.

[0071] In particular, to increase opacity and / or variation of the color impression, the coating preferably comprises at least one pigment. For the purposes of this disclosure, a pigment is understood to be a particle-based colorant. Advantageously, the pigment according to this disclosure is also temperature-stable and is preferably a ceramic colorant. In general, for the purposes of this disclosure, a colorant (or pigment) is understood to be a colorant consisting of particles, which may also be referred to here as pigment particles. Therefore, whenever it is stated in this disclosure that a coating comprises a pigment, it is understood that the coating comprises particles of a specific pigment or colorant, i.e., particles with the composition of the pigment or colorant.

[0072] Ceramic colorants or ceramic pigments as such are known to those skilled in the art. These can include, for example, metallic mixed oxides such as hematites and spinels, or pure oxides such as TiO2 or Fe3O4. Typical pigment sizes can range from an average of 0.15 µm to 5 µm, with the d 90 The particle size, based on the equivalent diameter, can be as low as 15 µm. However, finer particle sizes may be preferred, as they are easier to print.

[0073] When pigments are used in the coating, their concentration can be kept low due to the high optical density of the glass-ceramic material used as a filler. This means that the coating's already low coefficient of thermal expansion (resulting from the low coefficient of thermal expansion of the glass-ceramic material used as a filler) is hardly increased.

[0074] According to a preferred embodiment, the coating of the glass or glass-ceramic disc is designed to have a porosity gradient, wherein the porosity of the coating decreases from the glass disc towards the surface of the coating.

[0075] The terms glass pane and glass-ceramic pane are used for panes with or without a coating, depending on the context. Whenever reference is made in this application to a "glass pane per se" or a "glass-ceramic pane per se", this expressly refers to an uncoated pane, and the information concerns, for example, the properties of the pane without a coating.

[0076] The coated glass or glass-ceramic sheet exhibits good strength. According to embodiments, the coated glass or glass-ceramic sheet generally exhibits, particularly in the area where the coating disclosed herein is applied, a flexural strength of at least 5 MPa and at most 60 MPa, for example, between 5 MPa and at most 55 MPa. Preferred values ​​are at least 20 and at most 50 MPa, preferably at least 25 MPa. In this way, sufficient strength of the coated glass sheet is achieved for use, for example, as a sheet in a composite.Mechanical strength, such as flexural strength, is a statistical value. Therefore, the same pane would not be tested for flexural strength before and after coating. Rather, the preceding statement refers to tests conducted on uncoated and coated glass panes of the same composition and design. Flexural strength, or tensile flexural strength, is a defined parameter and denotes the maximum tensile stress a body or material can withstand when subjected to bending. Flexural strength is defined by how a specimen behaves in a bending test until it breaks at maximum stress. Within the scope of this disclosure, flexural strength refers to the strength of the glass pane, also known as double-ring tensile flexural strength, which was determined according to DIN 1288-5.Within the scope of this disclosure, the arithmetic mean is given as the strength value in each case. The so-called MOR (Modulus of Rupture) is an index for flexural strength.

[0077] According to one embodiment, the coverage of at least one side of the glass pane with the coating is at least 10% and at most 80%, preferably at least 15% and at most 65% of the total surface of the side of the pane on which the coating is applied.

[0078] In the context of this disclosure, a disc is generally understood to be a plate-shaped body. A glass disc (which may be coated or uncoated) is a disc comprising or made of glass. A body is plate-shaped if its spatial dimensions in one direction of a Cartesian coordinate system are at least one order of magnitude smaller than the spatial dimensions in the two other directions perpendicular to the first direction of the Cartesian coordinate system. In other words, the thickness of the body is at least one order of magnitude smaller than its length and width. The two principal surfaces of the disc, i.e., those whose size is determined by length and width, are also referred to simply as sides in this disclosure.

[0079] The coating can be applied to the glass pane as a solid, uninterrupted layer across at least one area, or it can be arranged, for example, in a dot matrix pattern. Combinations of these variations are also possible. For instance, a coating applied across the entire surface of the glass pane, without any breaks, can transition into a dot matrix pattern at the edges, typically towards the center. This is a common coating configuration, where the coating is structured on the glass pane, for glass panes used in vehicle windshields.

[0080] The binder is glass-based.

[0081] A glass-based coating is generally understood to be a coating that contains at least a predominantly (i.e., more than 50 wt.%) inorganic, amorphous binder. In particular, such a glass-based coating may also contain a binder that is essentially (i.e., at least 95 wt.%) or even entirely inorganic and amorphous. In addition to the binder, a glass-based coating may generally include other components.

[0082] The binder is in the form of a glass frit.

[0083] The coating is formed as an enamel layer. For the purposes of this disclosure, enamel coatings or enamel layers are understood to be coatings that incorporate glass frit or glass flux as a binder. During the firing of such coatings, the components of the glass flux, i.e., the glass frit, melt, and a melting reaction zone can form on the surface of the substrate, for example, the glass sheet. For the purposes of this disclosure, the terms frit, glass frit, and glass flux are used synonymously. Furthermore, the molten glass flows and encapsulates any additional components contained within the enamel color or the coatings resulting from such a color, such as pigment particles and / or filler particles. In this way, particularly mechanically resistant coatings can be obtained.Furthermore, the surface of such a layer is glass-like and, depending on the exact composition of the glass frit, can even be quite similar to the composition of the glass pane. In this way, according to one embodiment, it is advantageous that the strength of the bond between the two glass panes of a laminate does not differ significantly in different areas, but rather that the bond is uniform across the entire surface of the glass pane.

[0084] In the context of this disclosure, a glass flux or (synonymously) a glass frit is understood to be a glass-based binder suitable for forming a glaze and / or enamel layer. In particular, it may be a glass powder suitable and intended for application to a substrate by means of a printing process, and the glass powder may also be mixed with other components, such as pigments. Preferably, such glass fluxes / glass frits have a lower melting point and / or softening point than the corresponding substrate material, in particular than the material of a glass sheet to be coated.

[0085] Preferably, the coating has a thickness between 1 µm and 30 µm, more preferably between 2.5 µm and 20 µm, more preferably between 3 µm and 10 µm, and most preferably not more than 7.5 µm. Therefore, the coating thickness is preferably at least 1 µm, more preferably at least 2.5 µm, and more preferably at least 3 µm. Therefore, the coating thickness is preferably at most 30 µm, more preferably at most 20 µm, more preferably at most 10 µm, and most preferably at most 7.5 µm.

[0086] According to a further embodiment, in at least a partial area of ​​the region of at least one side of the glass pane where the first coating is applied, a further coating, in particular as an intermediate layer between the glass pane and the first coating, is arranged. In this further embodiment, the entire coating disclosed herein thus comprises the first coating and the further coating. For the sake of brevity, the entire coating will subsequently be referred to simply as the coating in some instances.

[0087] Such an additional coating, which is arranged as an intermediate layer between the glass pane and the coating, can be advantageous for certain designs.

[0088] The terms "additional coating" and "first coating" do not refer to the order of application, but merely to the fact that the "first coating" is always present, while the additional coating is optional, depending on the specific embodiment. If only the first coating is present, it can also be referred to as a "coating".

[0089] In general, the paste used for coating with the first coating can comprise between 50 vol.% and 99.5 vol.% binder, for example glass frit, based on the solid fraction encompassed by the paste. In some embodiments, the binder content in the first coating is between 99.5 vol.% and 40 vol.%, preferably between 99.5 vol.% and 50 vol.%, and particularly preferably between 95 vol.% and 55 vol.%, for example between 80 vol.% and 60 vol.%, wherein glass frit preferably forms the binder. According to a further preferred embodiment, the binder content in the first coating can generally be between 78 vol.% and 50 vol.%.

[0090] The filler content in the first coating is preferably between 3.5 vol.% and 50 vol.% filler, preferably between 7.5 vol.% and 40 vol.% filler, particularly preferably between 10 vol.% and 35 vol.% filler, for example between 15 vol.% and 30 vol.% filler.

[0091] The glass-ceramic material used as a filler according to the invention is not colorless, unlike conventional fillers.

[0092] The glass-ceramic material used as a filler according to the invention has a low coefficient of expansion, unlike conventional fillers and especially unlike conventional colored additives such as pigments.

[0093] Due to the advantageous properties of the glass-ceramic material according to the invention, the coating of the coated glass or glass-ceramic disc preferably has an optical density of at least 0.1, preferably at least 0.2, and at most 4.5, for example at most 3, preferably at more than 2, at a coating thickness of 3.5 µm.

[0094] The optical density is determined in an area where the coating is applied over the entire surface.

[0095] According to one embodiment, the coated glass pane preferably has an optical density in the at least one area in which the coating is arranged, with a coating thickness of 3.5 µm, of at least 0.1, preferably at least 0.2, and at most 4.5, for example at most 3, preferably more than 1, particularly preferably more than 2.

[0096] Optical density, or color density, is used to characterize the absorption behavior of a coating compared to "absolute white." The denser the color layer, the less light can pass through it. Optical density is calculated using the following formula: OD=log(1R)

[0097] R is the reflectance. The optical density is determined using densitometers, specifically within the scope of this disclosure, in the direction perpendicular to the largest surface area of ​​the coating and thus the coated surface of the glass pane. The higher the optical density, the less transparent the coating appears.

[0098] According to a preferred embodiment, the first coating comprises between 0.5 vol.% and 40 vol.% pigment, preferably between 0.5 and 30 vol.% pigment, particularly preferably between 10 and 25 vol.% pigment, and most preferably between 5 vol.% and 20 vol.% pigment. Black pigments, e.g., Fe3O4 or CuCr2O4, are preferably used as the pigment.

[0099] With a pigment content in the aforementioned range, the optical density can be further increased.

[0100] Due to the advantageous properties of the glass-ceramic material according to the invention, the coating of the coated glass or glass-ceramic disc exhibits a particularly advantageous color appearance at a certain coating thickness.

[0101] The perceived color can be determined according to the knowledge of a person skilled in the art using the CIELAB color space, particularly under illumination with illuminant type D65, a viewing angle of 10°, and a thickness of 3.5 µm. The thickness can, in particular, be the thickness of the enamel layer. The L* value, the a* value, and the b* value of the CIELAB color space can be determined according to the knowledge of a person skilled in the art, particularly using the KONICA MINOLTA CM-700d spectrophotometer, with the enamel layer facing upwards. In the context of this disclosure, the L* value, a* value, and b* value were determined using the SCE (Specular Component Excluded) method. This method corresponds to the visual impression better than the SCI (Specular Component Included) method.

[0102] The L* coordinate of the coating can be in a range of 5 to 75, particularly preferably from 5 to 15. The L* coordinate can be at most 75, at most 50, at most 30, at most 20, preferably at most 15.

[0103] The a* coordinate of the coating can be in a range of -4 to 1, preferably from -3 to 0, and particularly preferably from -2.5 to 0.

[0104] The b* coordinate of the coating can be in a range of -2 to 13, preferably from -2 to 1.5, particularly preferably from -2 to 1.

[0105] Particularly preferred is a coating with L* of at most 75, preferably of at most 15, and with a* = 0.5 ± 1 and / or b* = 5 ± 7.5.

[0106] According to one embodiment, the coated glass or glass-ceramic disc preferably has, in at least one area in which the coating is arranged, the values ​​specified above for the coating thickness given above.

[0107] With a pigment content in the aforementioned range, the LAB values ​​can be shifted further towards a darker black, depending on the selection of pigments.

[0108] Since ceramic pigments commonly used in coatings, for example spinel-based pigments, have relatively high coefficients of thermal expansion compared to the materials of the discs being coated, such as borosilicate glasses or glass ceramics, it is advantageous that the presence of the glass ceramic material according to the invention in the coating allows the pigment content of the coating to be limited to the aforementioned low proportions. In some embodiments, pigments are even omitted entirely.

[0109] Another criterion for the visual impression is the gloss.

[0110] The gloss can be measured from the side of the coating or from the other side, the "viewing side," i.e., from the side of the substrate and thus through the substrate. In some embodiments, the gloss at 60°, measured from the side of the coating according to the invention, is in a range of 1 GU to 100 GU, in particular from 10 GU to 100 GU, from 45 GU to 100 GU, or from 45 GU to 70 GU. The gloss at 60° can, in particular, be at least 1 GU, at least 10 GU, or at least 45 GU. The gloss at 60° can, in particular, be at most 100 GU or at most 70 GU. The gloss at 60° can be determined according to the knowledge of a person skilled in the art, in particular using the RHOPOINT gloss meter according to known, established measurements. The gloss is expressed in "gloss units" (GU). Measured through the coating, the gloss at 60° has advantageous GU values ​​of 45 to 100.

[0111] In some embodiments, the coating passes the sclerometer test at a force of 10 N, particularly with a coating thickness in the range of 2.5 to 20 µm, such as 3 to 10 µm, especially 3.5 µm. The sclerometer test can be carried out according to the knowledge of a person skilled in the art, in particular with the Elcometer 3092 and a force of 10 N in accordance with AS3894.4, EN 438-2 and / or ISO 4586-2. "Passing" the test means that the tested samples are rated 0 or 0.5 according to the sclerometer scale, which ranges from 0 to 2 in increments of 0.5. "0.5" means that only slight indentations are visible on the enamel side in the tested area. "0" means that no changes are visible on the enamel side.

[0112] In some embodiments, the coating passes the spring hammer test with a drop weight of 248.12 g and a polyamide impact hemisphere, particularly with a coating thickness in the range of 2.5 to 20 µm, such as 3 to 10 µm, and especially 3.5 µm. The spring hammer test is a measure of fracture toughness and can be carried out according to the knowledge of a person skilled in the art. Testing is performed up to the maximum possible test height of 50 cm. For non-prestressed materials, results of just a few centimeters are already satisfactory, so that, within the scope of the disclosure, a result of 4 cm or more is considered a passing grade for the coating.

[0113] The fact that optical parameters (such as the CIELAB parameters or the optical density) are preferably determined at a coating thickness of 3.5 µm does not mean that the coating on the disk necessarily has such a thickness. The coating on the disk can have a thickness of 3.5 µm, but it does not have to. The thickness of 3.5 µm merely indicates the preferred reference thickness for optical measurements.

[0114] The transmittance, for example, depends on the thickness of the coating. Therefore, it is useful to specify a reference thickness. For instance, the optical density might be 3.5 µm² for a given enamel layer thickness. However, the actual coating thickness of the coated disc might be, for example, 7 µm. Thus, the invention also includes discs with a coating thickness of 7 µm, where the optical density is 3.5 µm² for a reference coating thickness.

[0115] Due to the advantageous properties of the glass-ceramic material according to the invention, the coating of the coated glass or glass-ceramic disc preferably has a linear coefficient of thermal expansion CTE20-300 between 3 * 10 -6 / K and 7 * 10 -6 / K is preferably 3.5 * 10 -6 / K to 6* 10 -6 / K, especially preferred between 3.5* 10 -6 / K to 5.5 * 10-6 / K on.

[0116] It has been shown that for the mechanical properties of the coated pane, it is advantageous if the coefficients of thermal expansion of the pane and the coating are matched, and in particular, as similar as possible. This is the case, for example, when using a borosilicate glass pane.

[0117] It can also be advantageous if the coefficient of thermal expansion of the coating is lower than that of the glass pane. In this way, compressive stress can be generated by the coating. This is referred to as "prestressing without a process." This is the case, for example, when using a soda-lime glass pane. The low-expansion fillers in the coating according to the invention are therefore also decisive for the final mechanical properties of the coated pane.

[0118] According to one embodiment, the glass of the glass pane, which preferably comprises SiO2 and Al2O3 and B2O3, has a linear coefficient of thermal expansion between 2 * 10 -6 / K and 6 * 10 -6 / K. This is advantageous because it allows the glass pane to be made using known, low-expansion borosilicate glasses, which inherently possess quite high glass strength. Furthermore, such glasses also exhibit quite good thermal resistance and are chemically quite resistant.

[0119] Preferably, the glass of the glass sheet according to one embodiment comprises at least 60 wt.% SiO2 to at most 85 wt.% SiO2 and / or at least 7 wt.% B2O3 to at most 26 wt.% B2O3. Such glasses are particularly advantageous because they offer a good compromise between good mechanical, chemical and thermal resistance on the one hand and good meltability on the other, without segregation tendencies and / or excessively high viscosity of the glass melt having a detrimental effect.

[0120] According to one embodiment, the glass-ceramic of the glass-ceramic disc, which preferably comprises SiO2 and Al2O3 and Li2O, has a linear coefficient of thermal expansion CTE20-700 between -0.5 * 10 -6 / K and 1 * 10 -6 / K. This is advantageous because it allows the glass-ceramic disc to be designed using known, low-expansion glass-ceramics, e.g., LAS glass-ceramics with main crystal phases such as keatite or high-quartz solid solution, or glass-ceramics with lithium disilicate, which already possess intrinsically high strength. Furthermore, such glass-ceramics also exhibit quite good thermal resistance and are also chemically quite resistant.

[0121] According to one embodiment, the glass or glass-ceramic disc has a thickness of at least 1 mm and at most 12 mm, preferably between 2 mm and 4 mm.

[0122] The paste used for coating with the first coating comprises, in addition to the glass-ceramic material as a filler and the binder and optional pigment, preferably at least one dispersion medium.

[0123] The dispersion medium or medium is advantageous for applying the paste to the glass or glass-ceramic sheet, for example, for applying the paste by means of a screen printing process. For the purposes of this disclosure, a paste is understood to be, in particular, a so-called decorative or color paste.

[0124] The binder comprises or consists of a glass frit, wherein the glass frit comprises at least the following oxide-based components in wt.%: SiO2 10 to 70 B2O3 10 to 26 Al2O3 more than 0 to 9.

[0125] In the case of high-bi frits, especially high-bi borosilicate frits, the glass frit may comprise a glass which includes at least the following components in wt.% on an oxide basis: Areas of high bi-content borosilicate frits Bi2O3 8-45 B2O3 15-25 SiO2 30 - 60 Total R2O 4-5 Alkali oxides Total RO ≤0,5 Alkaline earth oxides

[0126] The fritters specified in the preceding paragraph may optionally contain an Al2O3 content of more than 0 to 9 wt.%.

[0127] The following values ​​apply to the coefficient of thermal expansion α and the density of the aforementioned high-bi-content borosilicate frits: α[* 10 -6 / K] Density [g / cm³] 3 ] min max min max 4,7 7,9 2,4 4

[0128] In the case of high Zn-content frits, especially high Zn-content borosilicate frits, the glass frit can comprise a glass which includes at least the following components in wt.% on an oxide basis: Areas of high zinc content borosilicate frits ZnO > 50 B2O3 10-26 SiO2 10 -50 Total R2O ≤0,5 Alkali oxides Total RO ≤0,5 Alkaline earth oxides

[0129] The fritters specified in the preceding paragraph may optionally contain an Al2O3 content of more than 0 to 9 wt.%.

[0130] The following values ​​apply to the thermal expansion coefficient α and the density for the aforementioned high Zn-containing borosilicate frits: α[* 10 -6 / K] Density [g / cm³] 3 ] min max min max 3,5 5,5 3,2 4

[0131] In borosilicate frits, the glass frit can comprise a glass which contains at least the following components in wt.% on an oxide basis: Areas “Borosilicate” fries Bi2O3 0-15 ZnO 0-5 B2O3 15-26 SiO2 50-70 Total R2O 4-6,5 Alkali oxides Total RO 0-2,5 Alkaline earth oxides

[0132] The fritters mentioned in the preceding paragraph may optionally contain an Al2O3 content of more than 0 to 9 wt.%.

[0133] The following applies to the thermal expansion coefficient α and the density for the above borosilicate frits: α density [*10 -6 / K] [g / cm 3 ] min max min max 4 5,2 2,2 2,6

[0134] The paste is therefore formulated in such a way as to produce an enamel coating, with the glass frit advantageously comprising a borosilicate glass.

[0135] Solvents with a vapor pressure of less than 10 bar, particularly less than 5 bar, and especially less than 1 bar, are preferably used as the medium for screen-printable coating solutions. These can be, for example, combinations of water, n-butanol, diethylene glycol monoethyl ether, tripropylene glycol monomethyl ether, terpineol, and n-butyl acetate. The viscosity of the paste is adjusted as required. The medium can, in particular, comprise or consist of one or more glycol ethers, especially 2-(2-butoxyethoxy)ethanol and / or 2-butoxyethanol. The organic medium can, for example, contain or consist of 50 to 75 vol% 2-(2-butoxyethoxy)ethanol and 20 to 30 vol% 2-butoxyethanol. Appropriate organic and inorganic additives are used to adjust the desired viscosity.Organic additives can include hydroxyethyl cellulose and / or hydroxypropyl cellulose and / or xanthan gum and / or polyvinyl alcohol and / or polyethylene alcohol and / or polyethylene glycol, block copolymers and / or triblock copolymers and / or tree resins and / or polyacrylates and / or polymethacrylates. Generally, commercially available screen printing media based on, for example, glycol or terpineol are suitable, as are others.

[0136] In general, the paste can be used to obtain a glass or glass-ceramic disc with a coating, wherein the coating is an enamel layer and comprises a binder, here designed as glass frit (or glass flux), which includes the following components in wt.% on an oxide basis: SiO2 10 to 70 B2O3 10 to 26 Al2O3 more than 0 to 9.

[0137] Preferably, the paste is formulated to have a viscosity, preferably determined by a plate viscometer, between 1500 and 8000 mPas, more preferably between 2000 and 6500 mPas, and most preferably between 2500 and 5000 mPas. This allows the paste to be readily applied on an industrial scale to substrates, particularly glass or glass-ceramic sheets, using conventional application methods. Advantageously, the paste can be applied to the substrate, i.e., the glass or glass-ceramic sheet, by means of a printing process, particularly screen printing.

[0138] However, it may also be possible to adjust the viscosity differently, so that, for example, a lower viscosity is obtained, such as a viscosity of no more than 1500 mPas.

[0139] The coating can be produced by a) coating a glass or glass-ceramic disc with a paste containing the glass-ceramic material according to the invention, wherein the paste also contains an organic medium and optionally one or more pigments, and b) heat-treating the coated disc at a temperature of 600 °C to 950 °C for a duration of 15 seconds to 30 minutes, preferably 30 seconds to 20 minutes, particularly preferably not more than 15 minutes. The glass-ceramic material may have been produced according to the method disclosed.

[0140] If a coated glass pane is heat-treated according to b), the heat treatment of the coated pane preferably takes place between 600 °C and 750 °C.

[0141] If a coated glass-ceramic disc is heat-treated according to b), the heat treatment of the coated disc preferably takes place between 700 °C and 950 °C.

[0142] Another aspect of the present disclosure relates to a composite comprising a glass pane coated at least in certain areas according to one embodiment of the disclosure, and a further glass pane, wherein the coating is preferably arranged between the glass panes. Furthermore, the composite preferably comprises a polymeric layer, which is also arranged between the glass panes and bonds them together. The polymeric layer can, for example, be in the form of a film between the two glass panes, but it is also possible to initially apply the polymeric layer in liquid form, with the polymeric liquid hardening into a polymeric layer when the two glass panes are joined. Examples

[0143] The invention will be explained in more detail below using examples.

[0144] The glass sheet according to the present disclosure comprises a glass comprising SiO2 and Al2O3 and at least one component from the group Li2O, B2O3. The glass sheet according to the present disclosure preferably comprises a glass comprising SiO2 and Al2O3 and B2O3.

[0145] The glass pane preferably comprises a borosilicate glass; it preferably consists of a borosilicate glass.

[0146] The glass pane preferably has a linear coefficient of thermal expansion between 2 * 10 -6 / K and 6 * 10 -6 / K, preferably between 2 * 10 -6 / K and 5.5 * 10 -6 / K on.

[0147] According to a first embodiment, the glass can be given by a composition comprising the following components, each specified in wt.% on an oxide basis: SiO2 60 to 85, especially preferably up to 82 B2O3 7 to 26 Al2O3 0 to 12, preferably larger than 0 to 11, particularly preferably up to 7 Li2O 0 to 1 Na2O 0.5 to 6 K2O 0 to 3 MgO 0 to 6 CaO 0 to 5 SrO 0 to 4 ZnO 0 to 3 ZrO2 0 to 3.

[0148] Furthermore, other components commonly used in glassmaking may be included, such as refining agents. These are generally present in a concentration of no more than 2% by weight of the glass.

[0149] The following compositions may show deviations of 100% in the total weight percentage due to rounding errors caused by analysis.

[0150] An exemplary glass is given in the following composition range in wt.% based on oxides: SiO2 75 - 85 B2O3 10-15 Al2O3 1-3 Na2O 2-5 K2O 0-1 NaCl less than 0.5

[0151] An example composition of a glass in this composition range, in wt.%, based on oxides, is given as follows: SiO2 80,8 B2O3 12,7 Al2O3 2,4 Na2O 3,5 K2O 0,6 NaCl 0,1

[0152] Another glass is given in the following composition range in wt.% based on oxides: SiO2 73-83 B2O3 8-12 Al2O3 1-4 Na2O 2-4 K2O 1-3 MgO 1-3 CaO 1-3

[0153] Another exemplary composition of a glass in this composition range, in wt.%, based on oxides, is given as follows: SiO2 78,1 B2O3 9,8 Al2O3 2,5 Na2O 2,8 K2O 2,5 MgO 1,8 CaO 2,5

[0154] Another glass is given in the following composition range in wt.% based on oxides: SiO2 72-74 B2O3 13-15 Al2O3 5-6 Na2O 4-6 K2O 1-2 MgO 1-3

[0155] Another exemplary composition of a glass in this composition range, in wt.%, based on oxides, is given as follows: SiO2 72,5 B2O3 14,0 Al2O3 5,6 Na2O 5,1 K2O 1,4 MgO 1,1

[0156] The glass-ceramic disc according to the present disclosure comprises a glass-ceramic comprising SiO2 and Al2O3 and at least one component from the group Li2O, B2O3. The glass-ceramic disc according to the present disclosure preferably comprises a glass-ceramic comprising SiO2 and Al2O3 and Li2O.

[0157] The glass pane preferably comprises a LAS glass ceramic; it preferably consists of a LAS glass ceramic.

[0158] The glass-ceramic disc preferably has a linear coefficient of thermal expansion CTE20-700 between -0.5 * 10 -6 / K and 1 * 10 -6 / K, preferably between 0* 10 -6 / K and 0.5 * 10 -6 / K on.

[0159] According to one embodiment, the glass ceramic can be given by a composition comprising the following components, each given in mol% on an oxide basis: SiO2 60 to 80 Al2O3 8 to 18 Li2O 4 to 12 TiO2 0 to 4 ZrO2 0 to 4 SnO2 0 to 2

[0160] The main crystal phases of this system are preferably keatite solid solution and high quartz solid solution.

[0161] Table 1 lists example frit compositions for various applications. The components are specified in wt.% based on oxides. Table 1 Example 1 2 3 4 5 6 7 8 9 10 11 Al2O3 8,2 7,2 5,4 0,6 5,9 0,10 1,00 5,1 5,3 5,0 2,0 B2O3 18 22,8 24,0 24,6 21,5 15,70 12,75 21,9 22,9 23,4 8,3 BaO Bi2O3 14 10,0 10,0 11,0 43,25 CaO 1,3 1,2 0,5 0,5 0,1 CoO 2,9 K2O 0,1 1,7 1,8 0,8 1,75 Li2O 3,2 4,4 4,9 0,8 0,8 4,8 0,8 MgO 0,3 Na2O 5,2 1,2 0,2 6,1 2,4 2,5 2,75 SiO2 55 55,6 56,0 66,6 58,0 32,70 24,25 63,4 66,2 55,0 29,5 SrO 1,0 TiO2 1,6 ZnO 0,4 3,3 51,50 62,00 8,9

[0162] Table 2 lists green glass compositions used in the production of the glass-ceramic materials used as fillers in exemplary applications. The components are given in wt.% based on oxides. Table 2 Example GG1 GG2 Al2O3 20,0 15,7 BaO 1,2 1,0 CaO 0,4 0,3 Fe2O3 3,5 11,3 K2O 0,4 0,3 Li2O 3,5 2,8 MgO 0,3 0,2 MnO2 1,8 5,8 Na2O 0,5 0,4 SiO2 61,2 48,1 SnO2 0,3 0,2 TiO2 3,4 11,0 ZnO 1,5 1,2 ZrO2 0,9 0,7 Reducing agent 1,1 1,0

[0163] These green glass beads were ceramicized into glass ceramics.

[0164] Table 3 lists the various ceramization conditions and key properties, namely the coefficient of thermal expansion (CTE20-300), optical density (OD) in the visible range, grain size (d50) after milling the glass-ceramic material by ball milling with Al₂O₃ balls in isopropanol, the crystal phases and their proportions, and the proportion of residual glass phase in the respective glass-ceramics GK1 to GK4, which were produced from GG2. The CTE was measured for example GK5 (see Table 4), and for the other examples, it was estimated based on the differences in the composition of the crystal phases, whose respective CTE values ​​are known. Table 3 Example GK1 GK2 GK3 GK4 Ceramic profile 1100 °C / 6 min 730 °C / 5 h + 1100 °C / 6 min 730 °C / 5 h + 1150 °C / 6 min 1150 °C / 6 min CTE20-300C [ppm / K] 3.3 (estimated) 3.8 (estimated) 1.9 (estimated) 2.0 (estimated) OD >70 / mm d50 [µm] 1,37 β-Spodumene [wt.%] 51,2 53,6 48,8 46,8 Fe1+xTi2-xO5Mixed crystal[wt%] 8,9 6,4 17,5 19,7 Fe1+xTi2-xO5 mixed crystal Fe1.16Ti0.84O5 Fe1.67i1.4O5 Fe1.12Ti0.88O5 Fe1.14Ti0.88O5 Ilmenite (Fe,Mn)TiO3 [wt%] 13,4 18 1,3 0,5 Spinel (Fe,Mn)Ti2O4 [wt%] - - - - Mg-Zr-Ti-O [wt%] - - - - Residual glass phase [wt.%] 26,4 22 32,4 33

[0165] Table 4 lists the various ceramization conditions and key properties, namely the coefficient of thermal expansion (CTE20-300), optical density (OD) in the visible range, grain size (d50) after milling the glass-ceramic material by ball milling with Al₂O₃ balls in isopropanol, the crystal phases and their proportions, and the proportion of the residual glass phase of the respective glass-ceramics GK5 and GK6, which were produced from GG1, and GK7, which was produced from GG2. The CTE was measured for one example (GK5), and for the other examples, it was estimated based on the differences in the composition of the crystal phases, for which the respective CTE values ​​are known. Table 4 Example GK5 GK6 GK7 Ceramic profile 1100 °C / 6 min 730 °C / 5 h + 1100 °C / 6 min 1260 °C / 2 h CTE20-300C [ppm / K] 1.6659 (measured) 1.62 (estimated) 1.96 (estimated) OD >40 / mm >40 / mm d50 [µm] 1,66 nb nb β-Spodumene [wt.%] 71,44 74,7 45,6 Fe 1+x Ti 2-x O5 mixed crystal [wt%] 4,4 3,8 19 Fe 1+x Ti 2-x O5 Mischkristall Fe1.03Ti1.97O5 Fe1.02Ti1.98O5 Fe1.24Ti1.76O5 Ilmenite (Fe,Mn)TiO3 [wt%] - 0,8 - Spinel (Fe,Mn)Ti2O4 [wt%] 2,32 3,3 - Mg-Zr-Ti-O [wt%] 1,84 0,7 - Residual glass phase [wt.%] 20 16,7 35,4

[0166] Using the glass ceramic GK5, various coatings (exemplars A1 - A3) were produced and compared with other coatings (comparative examples V1 - V5).

[0167] The coating A1 contains as its sole filler 23.5 vol% of the glass-ceramic material GK5 according to the invention. The remainder is frit.

[0168] The coating A2 contains as its sole filler 16 vol% of the glass ceramic GK5, and it contains 7.5 vol% of the black pigment CuCr2O4 with a d50 of 0.6 µm. The remainder is frit.

[0169] The coating A3 contains as its sole filler 7.5 vol% of the glass-ceramic material GK5 according to the invention, and it contains 16 vol% of the black pigment CuCr2O4 with a d50 of 0.6 µm. The remainder is frit.

[0170] Coatings V1 to V5 contain no fillers, i.e., nothing of grade 1 to grade 6. Coating V1 consists solely of frit. Coatings V2 to V5 contain 23.5 vol% (V2), 20 vol% (V3), 10 vol% (V4), and 7.5 vol% (V5) of the black pigment CuCr₂O₄ with a d50 of 0.6 µm. They contain no fillers. Table 5 summarizes the compositions. Table 5 Example Layer (Vol.-%) French fry pigment filler V1 100 0 0 A1 76,5 0 23,5 A2 76,5 7,5 16 A3 76,5 16 7,5 V2 76,5 23,5 0 V3 80 20 0 V4 90 10 0 V5 92,5 7,5 0

[0171] The frit shown in Example 3 of Table 1 was used to produce the coatings. The coatings were produced using the pastes listed in Table 6. A commercially available screen printing medium based on 2-(2-butoxyethoxy)ethanol was used as the medium. Table 6 Paste (wt%) Example. French fry pigment filler medium achieved viscosity @ 200 / s V1 59,40 0,00 0,00 40,60 3100 A1 49,81 0,00 15,76 34,43 3700 A2 47,23 10,29 10,18 32,30 3900 A3 44,90 20,90 4,53 29,68 3700 V2 41,88 28,64 0,00 29,48 2900 V3 45,24 25,18 0,00 29,58 4500 V4 56,42 13,95 0,00 29,63 5700 V5 59,61 10,76 0,00 29,63 5600

[0172] To produce the coatings, the respective paste was applied to the disc and baked in a chamber oven for 4 minutes. A paste with a viscosity of approximately 3500 mPas and a screen printing screen with a mesh size of 110-34 were used for the coating. This resulted in a coating thickness of approximately 3.5 µm in each case.

[0173] Table 7 specifies the thickness of the glass pane to be coated. It was a borosilicate glass pane with a coefficient of thermal expansion of 3.3 × 10⁻⁶ / K.

[0174] The table lists the respective firing temperature.

[0175] The table lists the L*, a*, and b* values ​​of the coated discs. The designation "color side" indicates that the colorimeter is pointed at the coated side of the substrate. The values ​​were measured using SCE.

[0176] The table lists the gloss of the coated lenses. The value 60° indicates the angle at which the gloss was measured. The measurement was taken from the coated side.

[0177] The table lists the optical density of the coated lenses. The indication "through the lens" means that the measurement was taken from the side of the lens, not from the side of the coating.

[0178] The table lists the results of the sclerometer measurement at 10 N. "0.5" means that only slight pressure marks are visible on the enamel side in the tested area. "0" means that no changes are visible on the enamel side.

[0179] The table lists the results of the spring hammer test. It indicates the maximum drop height in cm that the sample can withstand without damage.

[0180] The table also provides information on the breaking strength [J]. It was calculated from the results of the spring hammer test using the formula 248.12 / 1000*9.81*drop height (cm) / 100. Here, 248.12 g is the weight of the falling object and 9.81 m / s is the falling velocity.

[0181] The table provides information on flexural strength. Within the scope of this disclosure, flexural strength refers to the strength of the disc, also known as double-ring flexural tensile strength, which was determined according to DIN 1288-5. The index given for flexural strength is the MOR (modulus of rupture) [MPa].

[0182] All tests, including the spring hammer test, the determination of flexural strength and the determination of fracture strength, were carried out on non-prestressed samples. Table 7 V1 A1 A2 A3 V2 V3 V4 V5 Disc thickness [mm] 3,8 3,8 3,8 3,8 3,8 3,8 3,8 3,8 Burn-in temperature [°C] 680 680 680 680 680 680 680 680 CTE20-300[10 -6 / K] 4,80 4,06 4,69 5,40 6,02 5,84 5,32 5,19 L* (color page) 83,53 72,74 14,5 14,41 7,13 9,03 7,13 8,03 a* (color page) -0,4 0,88 -0,29 -0,39 -0,01 -0,04 -0,01 -0,2 b* (color page) 1,05 12,3 -1,79 -1,7 -1,59 -2,13 -1,59 -1,14 Gloss 60°[GU] (due to the coating) 96,7 49,9 50,4 62,3 44,4 82,8 82,8 91,6 OD (through the disc) 0,1 0,2 1,2 2,1 2,4 2,5 2,5 0,9 Sclerometer10N 0,0 0,5 0,5 0,5 0,5 0,0 0,0 0,0 Spring hammer [drop height [cm]] 7,3 25,8 10,5 4,0 4,8 3,7 3,7 4,8 Breaking strength [J] 0,2 0,6 0,3 0,1 0,1 0,1 0,1 0,1 Double ring bending machine MOR[MPa] 36,7 30,6 nb 27,0 26,3 26,0 25,1 29,6

[0183] Table 7 illustrates the advantages of the glass-ceramic material and the coated discs according to the invention by providing information on the layer properties.

[0184] A comparison of the embodiments with both V1 and V2 to V5 shows the high increase in strength and the increase in optical density. Character description

[0185] The invention will be further explained below with reference to a figure. Fig. Figure 1 shows the crystal phases β-spodumene, Fe determined by XRD for GK5. 1+x Ti 2-x O5 mixed crystal and spinel mixed crystal.

[0186] Both the glass-ceramic material according to the invention and a glass or glass-ceramic sheet coated with it, in particular partially, are ideally suited for use in household appliances, especially for decorating an oven window or a fireplace viewing window, or in a vehicle, preferably in the automotive sector, particularly in a composite material, especially for decorating a windshield. A glass or glass-ceramic sheet for a vehicle is generally understood to be a glass sheet for mobile applications, for example, for aircraft and / or automobiles.

[0187] The combination of properties including high optical density, the desired dark color impression for the aforementioned applications, high fracture and flexural strength, also due to well-matched coefficients of expansion of the disc and coating, are the advantage of the present invention. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 4166519 A1

[0010] WO 2020247194 A1

[0010]

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