Substrates with improved scratch resistant coatings

Abstract

The invention relates to a coated substrate comprising a substrate (1) having a scratch-resistant coating (2), in which: the scratch-resistant coating (2) comprises a diamond-like carbon (DLC) layer forming a maximum overall DLC layer thickness of 20 nm, and this overall DLC layer thickness is split into at least two split DLC layers, which are separated by at least one dielectric layer, in which, starting from the substrate (1), the dielectric layer is separated from the substrate (1) by at least one dielectric layer. Forming the following sequence of layers:-a first split DLC layer (4)-a second dielectric layer (5)-a second split DLC layer (7); wherein the first split DLC layer (4) is arranged in close proximity to the substrate (1), or a first dielectric layer (3) having a layer thickness of 1 nm to 120 nm is formed in close proximity to the substrate (1) and in close proximity to the first split DLC layer (4). The invention also relates to a method for producing such a coated substrate and to the use thereof.

Description

[0001] The present invention relates to a coated substrate comprising a substrate having an improved scratch-resistant coating, and to a method for manufacturing such a scratch-resistant coated substrate.

[0002] For many applications, especially with transparent substrates, there is a desire to provide improved scratch resistance to the substrate surface, as even small scratches are clearly visible and detract from the substrate's aesthetic appearance. Furthermore, complete surface integrity is no longer guaranteed. For example, float glass inherently lacks high scratch resistance, but applying a suitable thin film can significantly improve the scratch resistance of the glass surface. This also applies, for example, to substrates made of polymers such as polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), and polystyrene (PS), which have relatively soft, easily scratched surfaces. Moreover, even relatively hard glass, such as soda-lime glass, used as assembly glass in the automotive industry, is susceptible to scratches, particularly from hard particles such as quartz sand, stones, or coins. This not only detracts from the appearance of the assembly glass but can also impair visibility if scratches occur frequently.

[0003] Layers or coatings made of diamond-like carbon (DLC) are particularly well-suited for this purpose, and their scratch resistance is well-known. WO92 / 05951 A1 describes a transparent substrate coated with DLC, wherein a DLC layer of at least 20 nm thickness is applied over an intermediate layer previously applied to the surface of the substrate, and both layers are formed using a CVD (chemical vapor deposition) method.

[0004] Industrial methods for applying DLC ​​layers onto glass panes are known from patent literature. For example, CN105441871 A describes the manufacture of ultra-hard DLC layers using PVD and HIPIMS methods. CN104962914 A describes an industrial vapor deposition apparatus for depositing DLC ​​layers. Another apparatus for manufacturing DLC ​​layers is described in CN203834012 U. JP2011068940 A relates to a method for manufacturing hard, abrasion-resistant DLC layers.

[0005] WO 2004 / 071981 A2 relates to an ion beam technique for depositing DLC ​​layers on glass. This technique provides high-quality layers, but requires high process stability. In particular, the deposition of material (DLC material) onto the ion source can impair the operational stability of the ion source and lead to process interruptions, for example, due to problems related to electrical insulation, arc formation, and deposition.

[0006] Other common methods used for DLC deposition, such as chemical vapor deposition (CVD), are not suitable for large-area coatings on glass because they require high deposition temperatures and cannot be easily scaled up to large areas for technical reasons. Heating large glass sheets is very expensive in terms of energy consumption and is risky due to the possibility of glass breakage.

[0007] Other methods for depositing DLC ​​layers are disclosed in DE3442208 A1, DE102010052971 A1, DE19740793 A1 and US 5268217 A.

[0008] US 2010 / 0089615 A1 discloses a transparent conductive film comprising a transparent substrate; a transparent conductive oxide layer comprising at least one layer and containing zinc oxide as its main component, wherein the transparent conductive oxide layer is disposed on the transparent substrate; and a hard carbon film disposed on the surface of the transparent conductive oxide layer, wherein the transparent substrate, the hard carbon film, the transparent conductive oxide layer and the hard carbon film are arranged in this order, or the hard carbon film, the transparent substrate, the transparent conductive oxide layer and the hard carbon film are arranged in this order.

[0009] US 5,508,902 discloses a multilayer structure comprising a base substrate, a first intermediate layer, a second intermediate layer, a diamond-like carbon layer, and another first intermediate layer and a diamond-like carbon layer. This structure may alternatively include a base substrate, two first intermediate layers, a diamond-like carbon layer, and another first intermediate layer and a diamond-like carbon layer.

[0010] For transparent substrates, especially for glazing, DLC layers must have good transmittance or low absorption. In the automotive industry, for glazing such as windshields or side windows, a minimum transmittance of 70% is mandatory. Furthermore, relatively thick DLC layers, especially in curved glazing, can withstand high stresses, which can reduce and adversely affect scratch resistance, for example, due to crack formation. Both of these aspects of DLC layers—good transmittance and stress reduction—can be improved by reducing the layer thickness. However, DLC layers, especially thin ones, are susceptible to mechanical and chemical degradation, particularly due to the combination of UV radiation and oxygen and moisture. These are typical environmental conditions for products exposed to solar radiation. Conventional DLC layers on such substrates have very low durability, which can also reduce or limit product lifespan, thus significantly limiting the use of DLC layers, for example, in automotive glazing, glass doors, or glass walls.

[0011] Therefore, the object of the present invention is to provide a substrate having an improved scratch-resistant layer comprising DLC, which has an extended service life, particularly the service life of the scratch-resistant layer, and allows it to be used in products exposed to common environmental influences, thereby improving their durability and service life.

[0012] According to the present invention, a coated substrate is provided comprising a substrate having a scratch-resistant coating comprising a diamond-like carbon (DLC) layer, wherein the scratch-resistant coating has a maximum total DLC layer thickness of 20 nm, and this total DLC layer thickness is divided into at least two split DLC layers separated from each other by at least one dielectric layer, wherein, starting from the substrate, the following layer sequence is formed: - First Split DLC Layer - Second dielectric layer, and - Second split DLC layer.

[0013] According to the present invention, the first split DLC layer is arranged directly adjacent to the substrate, or a first dielectric layer having a layer thickness of 1 nm to 120 nm is formed adjacent to the substrate and adjacent to the first split DLC layer.

[0014] In embodiments where no first dielectric layer is formed, the first split DLC layer is therefore arranged adjacent to the substrate as described above, i.e., there is no layer disposed between the substrate and the first split DLC layer.

[0015] In an embodiment in which the first dielectric layer is formed, it is therefore arranged immediately adjacent to the substrate layer and immediately adjacent to the first split DLC layer as described above, i.e., the first dielectric layer is arranged between the substrate and the first split DLC layer, and therefore no other layer is arranged between the substrate and the first split DLC layer except for the first dielectric layer.

[0016] It has been surprisingly shown that by dividing the required total DLC layer thickness of the product into two or more split DLC layers, the present invention can provide a substrate comprising a scratch-resistant coating with excellent appearance and significantly improved properties, particularly higher chemical and mechanical resistance. The relatively thin design of the split DLC layers also allows for meeting specific minimum transparency requirements. On the other hand, this can be advantageously achieved with the same or even greater total DLC layer thickness compared to the use of only one total DLC layer in the prior art. Tests have shown that the coated substrate according to the present invention has very good scratch resistance. Furthermore, due to this division, the split DLC layers are thinner than the DLC layers used in the prior art while maintaining the same total DLC layer thickness, making them more flexible and less prone to cracking. If cracks do occur, especially those perpendicular to the layer surface, these cracks are relatively smaller and shallower in comparison. The dielectric layer is softer than the split DLC layer, so that the alternating dielectric (intermediate) layers can significantly reduce or even completely prevent crack propagation perpendicular to the layer. The advantage of replacing uniformly thick DLC layers with an alternating multilayer sequence of split DLC layers and dielectric layers according to the invention is that it avoids or reduces the diffusion of reactive molecules into the deeper split DLC layers, thus preventing these split DLC layers from degrading due to environmental influences such as UV radiation and moisture, and maintaining their full scratch resistance. This can significantly extend the lifespan of the coated substrate according to the invention. It also expands the range of products that can be used, particularly those exposed to environmental influences, especially sunlight and moisture.

[0017] The split DLC layer according to the invention is a commonly known diamond-like carbon layer. In the DLC layer, hydrogen-free or hydrogen-containing amorphous carbon is the main component, wherein the carbon can consist of a mixture of sp3 and sp2 hybrid carbons, and optionally, sp3 hybrid carbon or sp2 hybrid carbon can be dominant. Examples of DLCs are those named ta-C and a:CH. The split DLC layer used according to the invention can be independently doped or undoped. The formed split DLC layer can, for example, be doped with at least one foreign atom, wherein the foreign atom is preferably selected from silicon, oxygen, sulfur, nitrogen, chlorine, fluorine or a metal, wherein the metal is preferably selected from titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum or tungsten. Silicon doping is particularly preferred.

[0018] In a preferred embodiment, a first dielectric layer is formed between the substrate and the first split DLC layer, having a layer thickness of 1 nm to 120 nm, preferably 1 nm to 60 nm, and particularly preferably 1 nm to 20 nm. In other words, when the first split DLC layer is applied, the substrate (i.e., its surface) can be pre-coated with a first dielectric layer of 1 nm to 120 nm thickness. When using such a pre-coated substrate, the first DLC layer is applied onto this dielectric pre-coated layer. It has been shown that the adhesion and bonding of the split DLC layer to the substrate can be improved by the first dielectric layer (also referred to as the base layer). The base layer can continue to act as a barrier layer and prevent or reduce substrate corrosion that may be caused by diffusion, which also helps to increase service life and maintain scratch resistance.

[0019] The pre-coating layer used as the substrate for the first dielectric (base) layer can be a material selected from silicon carbide, silicon oxide, silicon nitride (Si3N4), silicon oxynitride, metal oxides, metal nitrides, metal carbides, or combinations thereof, wherein Si3N4 or TiN and / or doped Si3N4 is preferred, and Si3N4 doped with Zr, Ti, Hf, and / or aluminum is particularly preferred. Aluminum-doped Si3N4 is particularly preferred, for example, having 8% aluminum doping, which simplifies the method due to the improved conductivity of the material. In the case of metal oxides, metal nitrides, and metal carbides, the metal can be, for example, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, or tungsten. To fabricate the base layer, i.e., the first dielectric layer, known chemical vapor deposition methods, such as PVD, especially sputtering, preferably magnetron sputtering, CVD, or ALD, can be used.

[0020] In another preferred embodiment of the invention, an additional third dielectric layer is formed between the second dielectric layer and the second split DLC layer.

[0021] The first, second, and / or third dielectric layers may contain metal oxides, metal nitrides, metal carbides, or combinations thereof, or be composed of them. The first, second, and / or third dielectric layers preferably independently contain Si3N4 or SiO2. x N y SiO2, SiAl x N y SiAl x N y O z SiAl x O y SiZr x N y AlN, AlO x N y TiO2, TiN, TiZrx O y TiZr x N y , ZrN, ZrO2, HfN, HfO2, TaN, TaO2, NbN or SnZn x O y Silicon nitride or silicon oxide, or formed thereof, is preferred. SiAlN or aluminum-doped SiO2 is particularly preferred. To form such a layer, known chemical vapor deposition methods, such as PVD, especially sputtering, preferably magnetron sputtering, CVD, or ALD, can be used, for example.

[0022] In a particularly preferred embodiment, the second dielectric layer comprises Si3N4 and SiO2. x N y SiO2, SiAl x N y SiAl x N y O z SiAl x O y SiZr x N y AlN, AlO x N y TiO2, TiN, TiZr x O y TiZr x N y , ZrN, ZrO2, HfN, HfO2, TaN, TaO2, NbN, SnZn x O y Aluminum-doped silicon nitride or aluminum-doped silicon oxide, or formed from them.

[0023] In a very particularly preferred embodiment, the second dielectric layer comprises silicon nitride or silicon oxide, particularly aluminum-doped silicon nitride or silicon oxide, or is formed from them.

[0024] In a preferred embodiment of the coated substrate according to the invention, the third dielectric layer (if formed) and / or the second dielectric layer have a layer thickness in the range of 1 nm to 120 nm, preferably 1 nm to 60 nm, and particularly preferably 1 nm to 20 nm, independently of each other.

[0025] In another embodiment of the invention, a third and optional fourth split DLC layer are provided, each of which is separated from the other split DLC layers by at least one additional dielectric layer.

[0026] In another preferred embodiment of the coated substrate according to the invention, the split DLC layers have the same or different layer thicknesses, preferably each having the same layer thickness. In other words, the required total DLC layer thickness is preferably divided equally according to the number of split DLC layers.

[0027] In another preferred embodiment, the split DLC layers have a thickness ranging from 1 nm to 19 nm, preferably from 2 nm to 10 nm, and particularly preferably from 3 nm to 8 nm, independently of each other. In one embodiment of the coating substrate according to the invention, the split DLC layers may, for example, all have a thickness of 10 nm, or all have a thickness of 5 nm.

[0028] In a further embodiment, the alternating split DLC layers and dielectric layer of the scratch-resistant coating are transparent on the substrate. It has been shown that multilayer coatings containing split DLC layers not only exhibit better resistance to the effects of chemical and mechanical environments, but also exhibit improved transmittance (TL), compared to coatings with a single DLC layer of the same total thickness.

[0029] The substrate according to the invention can be a conductive or non-conductive substrate, wherein the substrate is preferably made of plastic, glass, glass-ceramic, or ceramic, and particularly preferably made of transparent glass or plastic. For example, the substrate may preferably be a glass, particularly flat glass, float glass, quartz glass, borosilicate glass, soda-lime glass, aluminosilicate glass, or transparent plastic, preferably rigid transparent plastic, especially a glass panel made of polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, polyvinyl chloride, and / or mixtures thereof.

[0030] Within the meaning of this invention, "transparent" means that the total transmittance of the substrate and / or the layers disposed thereon preferably has a visible light transmittance of greater than 50%, particularly greater than 60%, for example and especially preferably greater than 70%.

[0031] In a preferred embodiment, the coating substrate is a bent substrate and / or a tempered substrate.

[0032] The present invention also relates to a laminated glass sheet particularly for use in a carrier, comprising an outer glass sheet having an outer surface and an inner surface, and an inner glass sheet having an outer surface and an inner surface, which are connected to each other by a thermoplastic interlayer, wherein the outer glass sheet and / or the inner glass sheet are designed as a coated substrate according to the present invention.

[0033] The laminated glass panel is configured to separate the interior space, particularly the interior space of a vehicle, from the external environment within a window. The laminated glass panel is a laminate and comprises a first glass panel and a second glass panel, referred to in the context of this invention as an outer glass panel and an inner glass panel, bonded together via a thermoplastic interlayer. In the context of this invention, the term "inner glass panel" is understood to refer to the glass panel facing the interior space when in the installation position. The outer glass panel refers to the glass panel facing the external environment when in the installation position. In the context of this invention, the inner surface (or inner or side surface) is understood to be the surface of the glass panel facing the interior space when in the installation position. In the context of this invention, the outer surface (or outer or side surface) is understood to be the surface of the glass panel facing the external environment when in the installation position.

[0034] The surfaces of glass plates are typically named as follows: the outermost surface of the outer glass plate is called surface I. The innermost surface of the outer glass plate is called surface II. The outermost surface of the inner glass plate is called surface III. The innermost surface of the inner glass plate is called surface IV.

[0035] It should be understood that in the laminated glass sheet according to the invention, a scratch-resistant coating is formed on one or both exposed surfaces, i.e., on the outer surface of the outer glass sheet and / or the inner surface of the inner glass sheet.

[0036] Particularly preferably, the outer glass plate of the laminated glass sheet is designed as a coated substrate according to the invention, wherein a scratch-resistant coating is formed on the outer surface of the outer glass plate.

[0037] In a further preferred embodiment of the laminated glass sheet according to the invention, the inner glass sheet is designed as a coated substrate according to the invention, wherein a scratch-resistant coating is formed on the inner surface of the inner glass sheet.

[0038] Alternatively, both the outer and inner glass sheets of the laminated glass sheet can be designed as a coated substrate according to the invention, wherein a scratch-resistant coating is formed on the outer surface of the outer glass sheet and on the inner surface of the inner glass sheet.

[0039] The present invention further includes a method for manufacturing a coated substrate or laminated glass plate as described above in various embodiments, comprising at least the following steps: A) Provide substrate B) Optionally, a first dielectric layer is applied having a thickness of 1 nm to 120 nm. C) Apply the first split DLC layer D) Apply a second dielectric layer E) Optionally, apply a third dielectric layer. F) Apply the second split DLC layer.

[0040] The substrate provided in step A) can be a conductive or non-conductive substrate. Preferred substrates are made of plastic, glass, or glass-ceramic. In a particularly preferred embodiment, the substrate is made of glass, for example in the form of a glass sheet, or of plastic, such as polystyrene (PS), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG), or cyclic olefin copolymers or copolymers thereof. An example of a glass substrate is float glass or soda-lime glass. The thickness of the substrate, particularly the thickness of the glass substrate, can vary over a wide range, for example, from 0.1 mm to 30 mm.

[0041] In step B), optionally, a first dielectric layer is applied to a substrate, i.e., the surface of the substrate. In other words, when the first split DLC layer is applied in step C), the substrate may be uncoated or pre-coated with at least one first dielectric layer, also referred to as a base layer. When using a pre-coated substrate, the first split DLC layer is applied onto this dielectric pre-coating layer (base layer). The base layer can improve adhesion and bonding to the substrate.

[0042] In step D), a second dielectric layer is formed, and in step E), optionally, an additional third dielectric layer is formed. These layers are also referred to as intermediate layers. In other words, according to the invention, a multilayer structure is obtained in which split DLC layers and dielectric layers are formed alternately.

[0043] In step F), a second split DLC layer is applied.

[0044] The dielectric (base and intermediate) layers can be fabricated and formed by known chemical vapor deposition methods, such as PVD, especially sputtering, preferably magnetron sputtering, CVD or ALD.

[0045] In a preferred embodiment of the method, a split DLC layer is fabricated in steps C) and / or E) by a combined plasma-enhanced chemical vapor deposition (PECVD) / magnetron method (magnetron-PECVD method). Such a method is described, for example, in WO2019 / 020481 A1. This method involves coating a substrate (uncoated or pre-coated) with a diamond-like carbon (DLC) layer using a PECVD method (magnetron-PECVD) in a vacuum chamber in which a magnetron equipped with a target and a substrate are arranged, with plasma generated via the magnetron target. The method involves introducing at least one reactant gas into the plasma generated by the magnetron target in the vacuum chamber, thereby forming fragments of the reactant gas that are deposited on the substrate or pre-coated substrate to form a split DLC layer. This coating method is also suitable for coating substrates, such as glass plates, for example, carrier glass plates, with split DLC layers over large areas. The resulting split DLC layer exhibits excellent quality in terms of scratch resistance and appearance. This coating step can advantageously be performed using conventional deposition equipment. Preferably, acetylene or methane is used as the reactant gas, and a DC, AC-MF, or HiPIMS power supply is used, or a HiPIMS with a carbon target is used.

[0046] In a further embodiment of the method, one or more dielectric layers and a third split DLC layer and, if necessary, a fourth split DLC layer are applied alternately after step F).

[0047] According to the present invention, the maximum total DLC layer thickness, i.e. the sum of all applied split DLC layers, is 20 nm.

[0048] In a particularly preferred embodiment of the method according to the invention, the method further includes the following steps after step F): G) Apply a tempering protective layer. H) Preferably, heat treatment is performed at a temperature of 300°C to 800°C. I) Wash away the tempering protective layer.

[0049] In a preferred embodiment of the method, step H) includes bending and / or tempering the substrate obtained in step G).

[0050] In this way, tempered or bent coated substrates and laminated glass sheets according to the present invention can be manufactured.

[0051] Tempering protective layers designed as removable protective layers can protect underlying layers, particularly at least two split DLC layers, from degradation and corrosion during heat treatments, such as bending processes, tempering, or lamination, which are common in the automotive industry for glass sheets, to manufacture laminated glass sheets.

[0052] In a preferred embodiment, the removable tempering protective layer is a germanium-based or germanium oxide-based layer. Such a tempering protective layer and its fabrication are disclosed, for example, in WO 2023 / 275493A1.

[0053] The tempering protective layer can have a thickness of 10 nm to 100 nm, preferably between 15 nm and 40 nm.

[0054] The preferred embodiments of the coating substrate described above according to the present invention are also applicable to the methods according to the present invention.

[0055] The invention also extends to substrates that have had their tempering protective layer removed and are coated with a remaining scratch-resistant layer comprising at least two split DLC layers.

[0056] It should be understood that the tempered or bent substrate coated according to the invention can also be alternatively manufactured by applying the anti-scratch coating to the tempered or bent substrate via steps A) to F) described above. However, to manufacture the coated tempered or bent substrate according to the invention, it is preferable to apply the coating to an untempered and unbent substrate by performing steps B) to G), followed by a heat treatment as specified in step H), and then washing off the tempering protective layer as described in step I). In this way, a tempered or bent substrate coated according to the invention with a particularly durable anti-scratch coating can be manufactured.

[0057] The present invention also relates to the use of the coated substrate according to the invention or the laminated glass plate according to the invention in or as a carrier glass plate, particularly as a windshield of a carrier.

[0058] The invention is described in more detail below using non-limiting exemplary embodiments and the accompanying drawings. It should be noted that different aspects are described, each of which can be used individually or in combination. In other words, any aspect can be used with different embodiments of the invention unless explicitly stated as purely alternative.

[0059] The accompanying drawings are for illustrative purposes only and are not drawn to scale. The drawings do not limit the scope of the invention in any way.

[0060] In the attached diagram: Figure 1 This is a schematic cross-section through one embodiment of the coated substrate according to the invention. Figure 2 This is a schematic cross-section through another embodiment of the coated substrate according to the invention. Figure 3 This is a schematic cross-section through another embodiment of the coated substrate according to the invention. Figure 4These are photographs of the coated substrate according to the invention, having the structure according to Example 1, after a qualitative scratch resistance test. Figure 5 These are photographs of the uncoated reference substrate from Example 1 after a qualitative scratch resistance test. Figure 6 These are photographs of the coated substrate according to the invention, having the structure according to Example 2, after a qualitative scratch resistance test. Figure 7 These are photographs of the uncoated reference substrate from Example 2 after a qualitative scratch resistance test. Figure 8 These are photographs of the coated substrate according to the invention, having the structure according to Example 3, after a qualitative scratch resistance test. Figure 9 These are photographs of the uncoated reference substrate from Example 3 after a qualitative scratch resistance test. Figure 10 This is a flowchart of one embodiment of the method according to the present invention, and Figure 11 This is a flowchart of another embodiment of the method according to the present invention.

[0061] Figure 1 A schematic cross-section through one embodiment of a coated substrate according to the invention is shown, comprising a substrate 1 having a scratch-resistant coating 2. A first split DLC layer 4 is applied to the substrate 1. A second dielectric layer 5 is applied to the first split DLC layer 4. A second split DLC layer 7 is applied to the second dielectric layer 5. In the multilayer scratch-resistant coating 2, the individual layers 4, 5, and 7 are stacked on top of each other in a planar arrangement. The desired total DLC layer thickness distribution in the two split DLC layers 4 and 7, on the one hand, provides improved transmittance and transparency, while on the other hand, the relatively soft second dielectric interlayer 5 also significantly reduces or prevents crack formation and crack propagation perpendicular to the planar layers. This can significantly improve and extend the durability of the scratch-resistant coating and its perfect function and behavior.

[0062] Figure 2 A cross-section through another embodiment of the coated substrate according to the invention is schematically shown, which includes a substrate 1 having a scratch-resistant coating 2. Figure 2 The implementation scheme shown is the same as Figure 1The embodiment shown differs only in that a first dielectric layer 3, which may also be referred to as a base layer, is disposed between the substrate 1 and the first split DLC layer 4. This layer advantageously contributes to improving the adhesion and bonding of the multilayer scratch-resistant coating 2 to the substrate 1. Furthermore, this base layer also acts as a barrier layer for the substrate 1 and prevents or reduces degradation of the first split DLC layer 4 applied to the first dielectric layer 3. In the multilayer scratch-resistant coating 2, the individual layers 3, 4, 5, and 7 are stacked on top of each other in a planar manner. The desired total DLC layer thickness distribution results in improved transmittance and transparency in the two split DLC layers 4 and 7, while the relatively soft dielectric intermediate layers 3 and 5 can also further significantly reduce or prevent crack formation and crack propagation perpendicular to the planar layers. This can significantly improve and extend the durability of the scratch-resistant coating and its perfect function and behavior.

[0063] Figure 3 A cross-section through another embodiment of the coated substrate according to the invention is schematically shown, which includes a substrate 1 having a scratch-resistant coating 2.

[0064] Figure 3 The implementation scheme shown is the same as Figure 2 The only difference in the illustrated embodiment is that an additional third dielectric layer 6 is formed between the second dielectric layer 5 and the second split DLC layer 7. Figure 3 In the illustrated embodiment, two dielectric layers 5 and 6, which may be referred to as separator layers or interlayers, are applied on the first split DLC layer 4 and separate the first split DLC layer 4 from the second split DLC layer 7. The desired total DLC layer thickness division results in improved transmittance and transparency in the two split DLC layers 4 and 7, while the relatively soft dielectric interlayers 3, 5, and 6 can also significantly reduce or prevent crack formation and crack propagation perpendicular to the planar layers. This can significantly improve and extend the durability of the scratch-resistant coating and its perfect function and behavior.

[0065] Example 1 In Example 1, as follows Figure 1The layer sequence shown constructs a coating substrate according to the invention. Substrate 1 is a 2.1 mm thick glass plate (clear glass). A 10 nm thick first split DLC layer 4 is applied directly to substrate 1, i.e., the glass surface. A second dielectric layer 5, i.e., a 10 nm thick silicon nitride layer, is applied over the first split DLC layer 4 as a softer intermediate layer with the second split DLC layer 7. The resulting layer sequence is shown in Table 1. The two split DLC layers 4 and 7 are constructed with the same layer thickness. In other embodiments according to the invention, the split DLC layers may also have different thicknesses. Due to the alternating arrangement and the softer second dielectric layer 5, crack propagation, particularly perpendicular to the layer extension direction, can be avoided or at least reduced. The glass plate with the split DLC multilayer coating was subjected to a scratch resistance qualitative (comparative) test as described below. Very good scratch resistance was maintained.

[0066] Table 1 .

[0067] Example 2 In Example 2, as follows Figure 2 The layer sequence shown constitutes a coating substrate according to the present invention.

[0068] Substrate 1 is a 2.1 mm thick glass plate (clean sheet glass). A first dielectric layer 3, i.e., a 15 nm thick silicon nitride layer, is applied directly to substrate 1, i.e., the glass surface, as a base layer. A 5 nm thick first split DLC layer 4 is applied onto the first dielectric layer 3. A second dielectric layer 5, i.e., a 10 nm thick silicon nitride layer, is applied onto the first split DLC layer 4 as a softer intermediate layer with the second split DLC layer 7. The resulting layer sequence is shown in Table 2. The two split DLC layers 4 and 7 are constructed with the same layer thickness. In other embodiments according to the invention, the split DLC layers may also have different thicknesses. Due to the alternating arrangement and the softer dielectric layers 3 and 5, crack propagation, particularly perpendicular to the layer extension direction, can be avoided or at least reduced. The glass plate with the split DLC multilayer coating was subjected to a scratch resistance qualitative (comparative) test as described below. Very good scratch resistance was maintained.

[0069] Compared to the multilayer structure from Example 1, in Example 2, both split DLC layers are thinner, i.e., 5 nm thick. Compared to Example 1, improved transparency (TL) is achieved, and improved adhesion and bonding are realized by providing a first dielectric layer 3 as a base layer.

[0070] Table 2 .

[0071] Example 3 In this embodiment, the coating substrate corresponds to Example 2 in terms of layer sequence and selected layer thickness, wherein the coating substrate undergoes heat treatment during the manufacturing process. First, a coating substrate having a layer structure as shown in Table 3 is provided. As can be seen in Table 3, the layer structure includes a 25 nm germanium layer as an additional tempering protection layer.

[0072] Table 3: Layer structure before heat treatment .

[0073] In Example 3, the tempering protective layer is a 25 nm thick germanium layer, which, as a removable protective layer, protects the underlying layers, particularly the two split DLC layers 4 and 7, from degradation and corrosion during high-temperature processing, such as the bending processes commonly used for glass sheets in the automotive industry. Advantageously, these tempering protective layers can be removed very easily, for example, by a washing process, to obtain a transparent, scratch-resistant coating product with a visually flawless appearance. The coating substrate according to the invention can also be used to manufacture windshields, side windows, rear windows, or roof windows for vehicles. Such scratch-resistant coated glass products can also be used as single-pane assembled glass in applications such as glass doors, shower rooms, or glass walls.

[0074] Two split DLC layers 4 and 7 with the same layer thickness of 5 nm were used. The first dielectric layer 3 (base layer) improves adhesion and bonding to the substrate and, particularly during heat treatment, also acts as a barrier layer to prevent the first split DLC layer 4 from being corroded due to diffusion and components from the substrate 1. The coated substrate as shown in Table 3 was subjected to heat treatment at 650°C for 8 minutes, and then the germanium oxide layer formed by the tempering protective layer during heat treatment was washed away in a washing process to obtain a coated substrate with the structure shown in Table 4, which was then subjected to a scratch resistance qualitative (comparative) test as described below. Very good scratch resistance has been maintained.

[0075] Table 4: Layer structure after heat treatment and washing processes .

[0076] Qualitative comparative test of scratch resistance The substrates coated according to the present invention from Examples 1, 2 and 3, and the uncoated substrate 1 used as a comparison and reference in each case, were subjected to actual scratch tests in order to qualitatively study the scratch-resistant properties under environmental influences.

[0077] The experiment consisted of a five-day alternating cycle of simulated sunlight, quartz sand blasting, and windshield wiper treatment under water spray.

[0078] According to the invention, the coated substrate, i.e., the glass plate with the scratch-resistant coating, showed no visual damage after the test, while the uncoated control glass plate showed obvious scratches from sand and windshield wipers.

[0079] Figure 4 The images show photographs of the substrate according to the invention from Example 1, coated according to Table 1, after a qualitative scratch resistance test.

[0080] Figure 6 The image shows a photograph of the substrate according to the invention from Example 2, coated according to Table 2, after a qualitative scratch resistance test.

[0081] Figure 8 The image shows a photograph of the substrate according to the invention from Example 3, coated according to Table 4, after a qualitative scratch resistance test.

[0082] Figure 5 , 7 Images 9 and 9 respectively show photographs of the uncoated reference substrate (glass plate) after a qualitative scratch resistance test.

[0083] According to the present invention, a substrate 1 with a scratch-resistant coating 2 can be provided, exhibiting a transparency greater than 60%, particularly also greater than 70%, possessing excellent chemical and mechanical stability, and which can be further tempered, i.e., subjected to heat treatment or forming processes, such as bending processes. The multilayer scratch-resistant coating 2 obtained and provided according to the present invention exhibits improved resistance to crack formation and crack propagation, as well as enhanced resistance to environmental impacts.

[0084] Figure 10 A flowchart illustrating one embodiment of the method according to the invention is shown. In a first step P1, a substrate 1 is provided. In an optional second step P2, a first dielectric layer 3 having a layer thickness of 1 nm to 120 nm is applied to the substrate 1. In a subsequent third step P3, a first split DLC layer 4 is applied to the substrate 1, or, if step P2 has already been performed, to the first dielectric layer 3. In a subsequent fourth step P4, a second dielectric layer 5 is applied to the first split DLC layer 4. In an optional fifth step P5, a third dielectric layer 6 is applied to the second dielectric layer 5. In a subsequent sixth step P6, a second split DLC layer 7 is applied to the second dielectric layer 5, or, if step P5 has already been performed, to the third dielectric layer 6. A maximum total DLC layer thickness of 20 nm is formed, i.e., the sum of the thicknesses of at least two split DLC layers separated from each other by at least one dielectric layer is a maximum of 20 nm.

[0085] Figure 11 A flowchart showing another embodiment of the method according to the present invention is displayed. Steps P1 to P6 correspond to Figure 10 Steps P1 to P6 of the method shown. Furthermore, in Figure 11 In an embodiment of the method shown, step P6 is followed by step P7, in which a tempering protective layer is applied to the second split DLC layer 7. In the subsequent step P8, heat treatment is preferably performed at a temperature of 300°C to 800°C. Then, step P9 is performed. In this step, the tempering protective layer is washed away, thereby obtaining the coated substrate according to the invention.

[0086] List of reference numerals 1. Substrate 2. Scratch-resistant coating 3 First dielectric layer (optional base layer) 4. First split DLC layer 5. Second dielectric layer (intermediate layer) 6. Third dielectric layer (optional intermediate layer) 7. Second split DLC layer.

Claims

1. A coated substrate comprising a substrate (1) having a scratch-resistant coating (2), wherein the scratch-resistant coating (2) comprises a diamond-like carbon (DLC) layer. A maximum total DLC layer thickness of 20 nm is formed, and this total DLC layer thickness is divided into at least two split DLC layers, which are separated from each other by at least one dielectric layer. in, Starting from the substrate (1), the following layer sequence is formed: - First split DLC layer (4) - Second dielectric layer (5) - Second split DLC layer (7), And wherein the first split DLC layer (4) is arranged in close proximity to the substrate (1), or a first dielectric layer (3) having a layer thickness of 1 nm to 120 nm is formed in close proximity to the substrate (1) and in close proximity to the first split DLC layer (4).

2. The coated substrate according to claim 1, wherein the first dielectric layer (3) is formed between the substrate (1) and the first split DLC layer (4).

3. The coated substrate according to claim 1 or 2, wherein the second dielectric layer (5) comprises Si3N4 and SiO2. x N y SiO2, SiAl x N y SiAl x N y O z SiAl x O y SiZr x N y AlN, AlO x N y TiO2, TiN, TiZr x O y TiZr x N y , ZrN, ZrO2, HfN, HfO2, TaN, TaO2, NbN, SnZn x O y Aluminum-doped silicon nitride or aluminum-doped silicon oxide, or formed from them.

4. The coating substrate according to claim 3, wherein the second dielectric layer (5) comprises silicon nitride or silicon oxide, particularly preferably aluminum-doped silicon nitride or silicon oxide, or is formed therefrom.

5. The coated substrate according to any one of claims 1 to 4, wherein an additional third dielectric layer (6) is formed between the second dielectric layer (5) and the second split DLC layer (7).

6. The coated substrate according to any one of claims 1 to 5, wherein the first dielectric layer (3) and / or the third dielectric layer (6) independently comprises Si3N4 and SiO2. x N y SiO2, SiAl x N y SiAl x N y O z SiAl x O y SiZr x N y AlN, AlO x N y TiO2, TiN, TiZr x O y TiZr x N y , ZrN, ZrO2, HfN, HfO2, TaN, TaO2, NbN or SnZn x O y Silicon nitride or silicon oxide is preferred, with aluminum-doped silicon nitride or silicon oxide being particularly preferred, or formed from them. And / or wherein the first dielectric layer (3) has a layer thickness of 1 nm to 60 nm, preferably 1 nm to 20 nm, And / or the second dielectric layer (5) and / or the third dielectric layer (6) therein independently have a layer thickness of 1 nm to 120 nm, preferably 1 nm to 60 nm, particularly preferably 1 nm to 20 nm.

7. The coated substrate according to any one of claims 1 to 6, wherein a third and optionally a fourth split DLC layer are provided, each of which is separated from the split DLC layer by at least one additional dielectric layer.

8. The coating substrate according to any one of claims 1 to 7, wherein the split DLC layers (4, 7) have the same layer thickness, and / or the split DLC layers (4, 7) have a layer thickness in the range of 1 nm to 19 nm, preferably 2 nm to 10 nm, particularly preferably 3 nm to 8 nm.

9. The coated substrate according to any one of claims 1 to 8, wherein the coated substrate is a bent substrate and / or a tempered substrate.

10. A laminated glass sheet comprising an outer glass sheet having an outer surface and an inner surface, and an inner glass sheet having an outer surface and an inner surface, wherein they are bonded to each other by a thermoplastic interlayer, wherein the outer glass sheet and / or the inner glass sheet are formed as a coating substrate according to any one of claims 1 to 9.

11. A method for manufacturing a coated substrate according to any one of claims 1 to 9 or a laminated glass sheet according to claim 10, comprising at least the following steps: A) Provide substrate (1), B) Optionally, a first dielectric layer (3) is applied, having a layer thickness of 1 nm to 120 nm. C) Apply the first split DLC layer (4), D) Apply a second dielectric layer (5), E) Optionally, a third dielectric layer (6) is applied. F) Apply the second split DLC layer (7), The maximum total DLC layer thickness is 20 nm.

12. The method of claim 11, further comprising the following steps: G) Apply a tempering protective layer. H) Preferably, heat treatment is performed at a temperature of 300°C to 800°C. I) Wash away the tempering protective layer.

13. The method of claim 12, wherein step H) comprises bending and / or tempering the substrate obtained in step G).

14. The method according to claim 12 or 13, wherein the tempering protective layer is a germanium-based or germanium oxide-based layer, and preferably has a layer thickness of 10 nm to 100 nm, particularly preferably between 15 nm and 40 nm.

15. Use of the coated substrate according to any one of claims 1 to 9 or the laminated glass sheet according to claim 10 in a carrier glass sheet or as a carrier glass sheet, particularly as a windshield of a carrier.

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