Composite pane with opaque masking region

Abstract

The invention relates to a composite pane (10) with an opaque masking region (M) and a transparent through-vision region (D), comprising flat atop one another in this order: - a reflective layer (6) comprising a reflective portion (6.1); - an outer glass pane (1) having an outer face (I) and an inner face (II); - a masking layer (9) forming the opaque masking region (M); - a conductive coating layer (4); - a busbar (5) arranged in the opaque masking region (M) of the of the composite pane (10); - an intermediate layer (3); and - an inner glass pane (2) having an outer face (III) and an inner face (IV), wherein - the reflective portion (6.1) of the reflective layer (6) is printed onto the outer face (I) of the outer glass pane (1) at least in a region of the underlying busbar (5), thereby covering the busbar (5), and - the reflective layer (6) has, in the reflective portion (6.1), an average reflectivity for visible light of at least 90 %.

Description

[0001] SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0002] 1

[0003] Composite Pane with Opaque Masking Region

[0004] The invention relates to a composite pane with an opaque masking region, a method for its production, and its use.

[0005] In vehicles and buildings, composite panes are used to separate an interior space from exterior surroundings whilst allowing through-vision from the interior towards the exterior and vice versa. However, the through-vision through the composite panes may, especially in cases where outside air is colder and / or more humid than inside air, be impaired by condensation of small water droplets, usually on an outer face of the composite pane. Furthermore, especially in case of vehicles, precipitation in the form of water or snow can freeze on the outer face of the composite pane, requiring solutions for removal of condensation, ice, and / or snow.

[0006] Prior art examples of composite panes are known from US 2024 / 157768 A1 and US 2024 / 0278539 A1.

[0007] Different solutions have been proposed for removal of condensation, ice, and / or snow. For example, in motorised vehicles, composite panes such as windscreens are heated by a flow of warm air from the inside, by small wires embedded in the composite pane, or by a conductive coating layer applied to the composite pane. In case embedded wires or conductive coating are used for heating of the composite pane, a current is applied to the wires or the conductive coating. Due to the electrical resistance of the wires or the coating, the current flowing therein will generate a certain amount of heat, thereby slowly removing condensate, ice, and / or snow present on the outer face of the composite pane.

[0008] However, in recent years, vehicles have been equipped with composite panes having a relatively large surface area, sometimes even extending from the front of the vehicle across the roof all the way to the back. Given this increase in surface area, previously known solutions may not provide sufficient thermal energy to efficiently remove condensate, ice, and / or snow from the composite pane in a reasonable amount of time.

[0009] The object of the present invention is to mitigate the above identified shortcomings.

[0010] This is achieved by the composite pane according to independent claim 1. Preferred embodiments are apparent from the dependent claims and the entire disclosure.

[0011] The composite pane with an opaque masking region and a transparent through-vision region according to the invention comprises flat atop one another in this order:

[0012] - a reflective layer comprising a reflective portion; SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0013] 2

[0014] - an outer glass pane having an outer face and an inner face;

[0015] - a masking layer forming the opaque masking region;

[0016] - a conductive coating layer;

[0017] - a busbar arranged in the opaque masking region of the of the composite pane;

[0018] - an intermediate layer; and

[0019] - an inner glass pane having an outer face and an inner face, wherein the reflective portion of the reflective layer is printed onto the outer face of the outer glass pane at least in a region of the underlying busbar, thereby covering the busbar.

[0020] According to the invention, the conductive coating layer is directly applied to the masking layer forming the opaque masking region and the inner face of the outer glass pane in the through- vision region and is electrically conductively contacted by the busbar. The inventors have found that by applying the conductive coating layer to the masking layer (in the opaque masking region) and the underlying outer glass pane (in the through-vision region), the thermal conductivity and hence the energy input into the outer glass pane can be increased. It therefore becomes possible to heat composite panes with a comparatively large surface area using the current supplied by an onboard voltage supply of a vehicle.

[0021] In the context of this invention, the masking layer forming the opaque masking region is to be understood as a masking print applied to at least one face of the outer glass pane, for example, by screen printing or inkjet printing. The masking layer is usually made of an opaque enamel, comprising glass frit and a pigment. The masking layer is applied to the inner face of the outer glass pane, thereby creating the opaque masking region, which surrounds a central through- vision region of the composite pane in a frame-like manner. However, the masking region can also encompass areas which are formed by separate frames or extend into the through-vision region to a certain degree. Busbars are applied to the conductive coating layer in the area of the opaque masking region to electrically conductively contact the conductive coating layer.

[0022] In such an arrangement, however, the busbar may become visible from the outside of the vehicle, thereby impairing the overall visual appearance thereof. The inventors have also found that, by printing the reflective layer with the reflective portion onto the outer face of the outer glass pane at least in the region of the underlying busbar, the busbar can be reliably covered and concealed.

[0023] In the context of the invention, the term “underlying” refers to the fully assembled state of the composite pane and is to be understood in the sense of directly beneath or directly below. In other words: in the plan view of the composite pane with the outer face of the outer glass pane atop, SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0024] 3 the surface area of the busbar is completely covered by the reflective portion of the reflective layer; the busbar is hence not visible from the outside.

[0025] In the context of this invention, the term “conductive coating layer” refers to at least one layer of an electrically conductive material having a certain resistance to a current applied across the conductive coating layer, for example, 0.5 Q / square to 70 Q / square. The conductive coating layer is made from an electrically conductive material, for example, as a single-layer structure deposed on the outer glass pane by a single material-deposition step. The conductive coating layer is transparent, i.e. permeable to electromagnetic radiation, preferably electromagnetic radiation of a wavelength from 300 nm to 1300 nm and, in particular, to visible light (see below). The conductive coating may also be made of a multi-layer structure, but this is not preferred. In this case, the conductive coating contains two or more, for example, three, four, or five electrically conductive layers.

[0026] Irrespective of the number of layers, the conductive coating layer contains at least one metal, for example, silver, gold, copper, nickel, and / or chromium, or a metal alloy. The conductive coating layer particularly preferably contains at least 90 wt.-% of the metal, in particular at least 99.9 wt.- % of the metal. The conductive coating layer can be made of the metal or the metal alloy. The conductive coating layer particularly preferably contains silver or a silver-containing alloy. Such conductive coating layer have particularly advantageous electrical conductivity with, at the same time, high transmittance in the visible spectral range. The thickness of the conductive coating layer is preferably from 5 nm to 50 nm, particularly preferably from 8 nm to 25 nm. In this thickness range, advantageously high transmittance in the visible spectral range and a particularly advantageous balance between electrical conductivity and electrical resistance for heating of the outer glass pane are achieved.

[0027] Preferably, the busbars are implemented as a printed and burnt-in conductive structure. The printed busbars contain at least one metal, preferably silver. The electrical conductivity is preferably realised via metal particles contained in the busbar, particularly preferably via silver particles. The metal particles can be situated in an organic and / or inorganic matrix such as pastes or inks, preferably as burnt screen printing paste with glass frits. The layer thickness of the printed busbars is preferably from 5 pm to 40 pm, particularly preferably from 8 pm to 20 pm, and most particularly preferably from 10 pm to 15 pm. Printed busbars with these thicknesses are technically simple to realise and have advantageous current carrying capacity. The busbars are provided, in a manner known to the person skilled in the art, with connection cables, for example, in the form of flat conductors that are routed out of the composite pane in order to be connected to an external power source. SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0028] 4

[0029] According to the invention, the reflective layer has, in the reflective portion, an average reflectivity for visible light of at least 90 %. The term “visible light” refers to electromagnetic radiation having a wavelength between 380 nm and 780 nm. The term “reflectivity” refers to a ratio of reflected light to incident light of the reflective portion of the reflective layer of the composite pane, hence the amount of light being reflected by the reflective portion of the reflective layer. The reflectivity is determined at an angle of 8° (to a surface normal of the underlying outer face of the outer glass pane) with illuminant A (see, e.g., ISO 11664-2:2007) and a 2° detector. The reflectivity of the reflective layer is determined on the fully manufactured / laminated composite pane; the specified reflectivity refers to the area of the reflective layer designated as the “reflective portion”. The term “average reflectivity for visible light” hence refers to the reflectivity of the reflective portion for electromagnetic radiation with the wavelength between 380 nm and 780 nm. This average reflectivity is determined as an integral over the given spectral range (see ISO 9050). Furthermore, the average reflectivity may preferably be calculated as the arithmetic mean of measurements taken at a minimum of three distinct points on the reflective portion of the reflective layer. The points are spaced apart by a certain distance of at least 5 mm, preferably at least 1 cm, 2 cm, or 5 cm (with upper limits at, for example, 50 cm, 30 cm or 10 cm). With the preferred reflectivity of the reflective coating, it becomes possible to reliably cover the underlying busbar. This can, for example, be advantageous with regard to the overall visual appearance of the composite pane, especially in case of the composite pane being used in a building or a vehicle.

[0030] The reflective layer preferably contains a metal oxide. The metal oxide is preferably selected from a group formed by titanium oxides, silicon oxides, zirconium oxides, tin oxides, zinc oxides, aluminium oxides, indium oxides, and transition metal oxides. Transition metals include copper, iron, cobalt, chromium, and manganese. The coating may also contain mixtures of the named oxides or mixed oxides of the named metals. With such metal oxides, optically appealing reflective properties can be achieved. Furthermore, the reflective layer containing metal oxide is able to withstand mechanical abrasion, e.g. from a wiper blade. The metal oxide content in the reflective coating is preferably at least 70 %, particularly preferably at least 80 %, most particularly preferably at least 90 %.

[0031] The reflective layer may have a coloured appearance due to the presence of colouring species, such as pigments or metal particles, e.g. gold. The oxide-based reflective layer is advantageously a sol-gel coating, i.e. a coating obtained by a sol-gel process. A sol-gel process typically comprises:

[0032] - the formation of a “sol”, i.e. a solution containing at least one precursor of the oxide to be deposited, SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0033] 5

[0034] - applying this solution to the surface to be coated,

[0035] - consolidation or densification of the coating by means of heat treatment.

[0036] The precursor comprises salts of the element whose oxide is to be deposited. Examples of organometallic compounds are alkoxides, for example tetraorthosilicate (TEOS) in the case of a silicon oxide layer, or titanium tetraisopropoxide in the case of a titanium oxide layer. The sol may be partially aqueous. It preferably comprises an organic solvent, for example an alcohol, particularly chosen from ethanol, isopropanol, butanol and glycols or glycol derivatives, and mixtures thereof. The sol may further contain viscosity-regulating agents, such as cellulose ethers or polyacrylates.

[0037] In a preferred embodiment, the reflective layer has, at least in the reflective portion, a thickness of 10 nm to 80 nm, preferably at least 15 nm, 20 nm, 25 nm, 30 nm, or 40 nm (with possible upper limits, independent thereof, of 75 nm, 70 nm, 65 nm, 60 nm, or 50 nm). The thickness is to be understood as the median thickness over a certain area, for example, measured in at least in three individual points. With the advantageous thickness of the reflective layer, the preferred reflectivity can be achieved while also ensuring that the reflective layer is sufficiently durable. The reflective layer may, in the example of composite pane being used in a vehicle, be subjected to mechanical and / or abrasive loads such as wiper blades wiping across the reflective layer.

[0038] In a preferred embodiment, the reflective layer further comprises a partially transparent portion, wherein the reflective layer has, in the partially transparent portion, an average reflectivity for visible light of at least 30 % and less than 90 %. The average reflectivity can be determined as is set out above. In other words: the reflective layer comprises the reflective portion and the partially transparent portion, and the reflectivity of these two portions differs. The reflective portion has the preferred reflectivity for visible light of at least 90 %, wherein the partially transparent portion has an average reflectivity between 30 % and 90 %. This difference in reflectivity allows to create a visually appealing surface for covering of the busbar (by the reflective portion of the reflective layer) and in the immediate surroundings of the busbar (by the partially transparent portion of the reflective layer). This can, for example, be advantageous with respect to the overall visual appearance of the composite pane.

[0039] In a preferred embodiment, the average reflectivity of the partially transparent portion of the reflective layer decreases with an increase in distance from the reflective portion of the reflective layer. The average reflectivity can be determined as is set out above. In other words: the average reflectivity of the partially transparent portion has a gradient, namely decreases with an increase in the distance from the reflective portion of the reflective layer (when viewed in a plan view with SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0040] 6 the outer face of the outer glass pane atop). This can, for example, be advantageous with respect to the overall visual appearance of the composite pane.

[0041] In a preferred embodiment, the conductive coating layer covers at least 90 % of the inner face of the outer glass pane. With the conductive coating layer covering at least 90% of the inner face of the outer glass pane it is possible to reliably heat the composite pane at least in the area covered by the conductive coating layer.

[0042] In a preferred embodiment, the conductive coating layer covers at most 95 % of the masking layer. By overlapping the conductive coating layer with the masking layer it becomes possible to reliably heat the composite pane also in areas having the enamel print. However, by limiting the size of the conductive coating layer with respect to the masking layer, edge corrosion of the conductive coating layer is avoided (see below). Furthermore, by overlapping the conductive coating layer with the masking layer in the specified range, a sufficiently large area for placement of the busbars and hence for electrically conductively contacting the busbars to the conductive coating layer is created.

[0043] The composite pane has multiple side edges, particularly preferably four side edges. The composite pane can, however, also include more than four side edges. In each case, at least two side edges of the composite pane are positioned opposite one another, essentially in pairs. In the case of an embodiment with four side edges, this yields two pairs of two opposite side edges each. The opposite side edges of a composite pane can run parallel to one another or nonparallel. The side edges need not be straight, but often have a curve. The length of opposite side edges can differ from one another. For example, the composite pane can have a trapezoidal outline. In a preferred embodiment, the composite pane has multiple side edges, for example, four side edges.

[0044] As laid out above, the conductive coating layer preferably does not extend to circumferential side edges of the composite pane but is spaced apart from these side edges on all sides such that the conductive coating layer is safely embedded in the laminated glass and protected from corrosion and damage. Optionally, an edge seal can also be applied around the conductive coating layer to further protect the coating layer from corrosion. A distance between the conductive coating layer and the respective side edges preferably measures at least 5 mm, more preferably at least 6 mm, 7 mm, 8 mm, or 9 mm (with possible upper limits, independent thereof, of 15 mm, 14 mm, 13 mm, 12 mm, 11 mm, 10 mm).

[0045] The busbar or the busbars for electrically conductively contacting the conductive coating layer are preferably arranged at a distance of 0 mm to 100 mm, preferably 1 mm to 50 mm, particularly SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0046] 7 preferably 1 mm to 20 mm, from the circumferential edge of the composite pane. As a result, the pane area available for through-vision is advantageously enlarged. Furthermore, the busbars can, in this manner, be concealed by the circumferential masking print customary in the automotive sector and are more easily contactable with wiring, for example, to electrically conductively contact the busbar to the onboard voltage supply of the vehicle.

[0047] The composite pane is a laminated pane with an outer glass pane and an inner glass pane joined by the intermediate layer. The intermediate layer preferably comprises a thermoplastic laminating film, which bonds the outer glass pane to the inner glass pane. The thermoplastic laminating film can, for example, be formed by a single thermoplastic film. The thermoplastic laminating film can also be formed from sections of different thermoplastic films whose side edges are adjacent. These can, if need be, also be used for embedding additional films comprising functional layers, for example, infrared-reflecting layers or acoustically damping layers. The thermoplastic laminating films can also include tinted or coluored regions. Such films can be obtained, for example, by coextrusion. Alternatively, an untinted film segment and a tinted or coloured film segment can be combined to form a thermoplastic laminating film. The tinted or coloured region can be homogeneously coloured or tinted, in other words, can have location-independent transmittance. However, the tinting or colouring can also be inhomogeneous; in particular, a transmittance progression or gradient can be realised. In one embodiment of the windscreen, the transmittance level in the tinted or coloured region decreases at least in sections with increasing distance from the upper roof edge. Thus, sharp edges of the tinted or coloured region can be avoided such that the transition from the sun visor to the transparent region of the windscreen is gradual, which appears more attractive aesthetically.

[0048] Preferably, the masking layer has an opacity of more than 90 %, preferably more than 92 %, 94 %, 96 %, 98 %, 99 %, or 99,5 %, for visible light. Automobile glazing, in particular windscreens, rear windows, and roof panels, usually have a surrounding peripheral masking print made of an opaque enamel, which serves in particular to protect the adhesive used for installation of the pane against UV radiation and to obscure it visually. This peripheral masking print is preferably also used to obscure the edges of the conductive coating layer that are situated in the edge region of the composite pane. The busbars and the required electrical connections are also installed in the region of the masking print. In this manner, the conductive coating layer is advantageously integrated into the appearance of the composite pane. Preferably, at least the outer glass pane used as an outer pane has such a masking print; particularly preferably, both the outer glass pane and the inner glass pane (outer glass pane and inner glass pane) are printed such that through- vision in the opaque masking region is prevented from both sides. SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0049] 8

[0050] The invention also includes a method for producing a composite pane according to the invention, comprising the steps of: a) providing a layer stack, comprising flat atop one another in this order: an outer glass pane having an outer face and an inner face; a masking layer forming the opaque masking region; a conductive coating layer; a busbar arranged in the opaque masking region of the of the composite pane; an intermediate layer; and an inner glass pane having an outer face and an inner face, b) joining the layer stack by lamination; and c) printing a reflective layer comprising a reflective portion onto the outer face of the outer glass pane, wherein the reflective portion of the reflective layer is printed onto the outer face of the outer glass pane at least in a region of the underlying busbar, thereby covering the busbar.

[0051] The lamination of the layer stack with the intermediate layer and the inner glass pane can be done using common lamination methods. For example, so-called autoclave processes can be carried out at an increased pressure of about 10 bar to 15 bar and temperatures of 130 °C to 145 °C for about 2 hours. Alternatively, autoclave-free methods are also possible. Vacuum bag or vacuum ring processes known per se work, for example, at around 200 mbar and 80 °C to 110 °C. The layer stack can also be pressed into a composite disk in a calender between at least one pair of rollers. Systems of this kind are known for manufacturing composite panes and normally have at least one heating tunnel in front of a pressing unit. The temperature during the pressing process, for example, is between 40 °C and 150 °C. Combinations of calendering and autoclave processes have proven particularly effective in practice. Alternatively, vacuum laminators can be used. These consist of one or more heatable and evacuable chambers in which the outer and inner panes are laminated in about 60 minutes at reduced pressures of 0.01 mbar to 800 mbar and temperatures of 80 °C to 170 °C.

[0052] In a preferred embodiment, preferably prior to step a), the masking layer is printed onto the inner face of the outer glass pane using a screen printing process (e.g. using a mesh / screen) and / or, preferably in step c), the reflective layer is printed onto the outer face of the outer glass pane using a digital printing process (e.g. digital inkjet printing, sometimes also referred to as “Drop on Demand”) or a 3D-printing process. This allows to reliably produce the masking layer with commonly available printing techniques and / or to produce the reflective layer having the preferred properties reliably. Furthermore, by printing the reflective layer onto the outer face of the outer SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0053] 9 glass pane, existing manufacturing processes for the composite pane can be used as the printing of the reflective layer may be performed after manufacturing of the layer stack, for example, in a different location or at a later time in the manufacturing process.

[0054] In a preferred embodiment, preferably prior to step a) and after printing of the masking layer (see before), the conductive coating layer is applied to the inner face of the outer glass pane, thereby covering the opaque masking region and the transparent through-vision region of the composite pane at least partially. The conductive coating layer is applied using, for example, a magnetron sputtering process.

[0055] In a preferred embodiment, the method further comprises the step of: d) sintering the printed reflective layer in a firing step by applying a surface temperature of at least 550 °C, preferably at least 560 °C, or 570 °C, and at most 600 °C, preferably at most 590 °C, or 580 °C, to the outer face of the outer glass pane having the printed reflective layer for at least 200 s, preferably at least 250 s, or 300 s, with possible upper limits (independent thereof) of 400 s, 380 s, 360 s, or 340 s.

[0056] The invention also includes use of a composite pane according to one of preceding embodiments as glazing for a motor vehicle, preferably as windscreen, sunroof, and / or rear window.

[0057] In general, “a” and “an” in the context of this disclosure are to be read as indefinite articles and thus always also as “at least one”, unless expressly stated to the contrary.

[0058] The invention is explained in detail with reference to drawings and exemplary embodiments. The drawings are schematic representations and are not to scale. The drawings in no way restrict the invention. Shown is in:

[0059] Fig. 1a a plan view of a composite pane 10 according to the invention used as a windscreen of a motor vehicle,

[0060] Fig. 1b a cross-section through the composite pane of Fig. 1a along the section line X-X',

[0061] Fig. 2 an enlarged plan view of the reflective layer 6; and

[0062] Fig. 3 an exemplary embodiment of the method according to the invention using a flowchart.

[0063] Fig. 1a depicts a plan view of a composite pane 10 according to the invention, which is implemented as a windscreen of a motor vehicle (not shown). The composite pane 10 according to the invention has, in the implementation as a windscreen, a circumferential masking layer 9, SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0064] 10 which conceals the adhesive connection of the windscreen to the vehicle body. The masking layer 9 forms an opaque masking region M which surrounds the central transparent through-vision or see-through region D of the composite pane 10. As can be seen in Fig. 1a, two reflective layers 6 are printed onto the composite pane 10, each extending in parallel to at least one of the side edges 10.1 , 10.2, 10.3, 10.4 of the composite pane 10.

[0065] Fig. 1b depicts a cross-sectional view of the windscreen of Fig. 1a along a section line X-X'. The windscreen comprises flat atop one another in this order a reflective layer 6, an outer glass pane 1 , a masking layer 9, a conductive coating layer 4, a busbar 5, an intermediate layer 3, and an inner glass pane 2. The outer glass pane 1 has an outer face I and an inner face II, the inner glass pane 2 has an outer face III and an inner face IV. The inner face II of the outer glass pane 1 faces the outer face III of the inner glass pane 2. The masking layer 9 is printed onto the inner face II of the outer glass pane 1 , thereby forming the opaque masking region M (see also Fig. 1a). The conductive coating layer 4 is applied to the inner face II of the outer glass pane 1 and two busbars 5 are applied electrically conductively contacted to the conductive coating layer 4 at opposite ends 10.1 , 10.3 of the composite pane 10. The busbars 5 are surrounded by the intermediate layer 3, which is electrically insulating, and the inner glass pane 2 is provided on an opposite side of the intermediate layer 3.

[0066] As can be seen in the cross-sectional view of Fig. 1 b, the conductive coating layer 4 covers at least 90 % of the inner face II of the outer glass pane 1 while also covering at most 95 % of the masking layer 9. Furthermore, the conductive coating layer 4 is spaced apart from the side edges 10.1 , 10.2, 10.3, 10.4 of the composite pane 10, wherein a distance between the respective side edge 10.1 , 10.2, 10.3, 10.4 and the conductive coating layer measures 13 mm. The intermediate Iayer 3 is applied to cover the conductive coating layer 4 circumferentially and on its surface facing away from the outer glass pane 1 to avoid corrosion of the intermediate layer 3.

[0067] With the conductive coating layer 4 covering at least 90% of the inner face II of the outer glass pane 1 it is possible to reliably heat the composite pane 10 at least in the area covered by the conductive coating layer 4. By overlapping the conductive coating 4 layer with the masking layer 9 it becomes possible to reliably heat the composite pane 10 also in areas having the enamel print. Furthermore, by overlapping the conductive coating layer 4 with the masking layer 9 in the specified range, a sufficiently large area for placement of the two busbars 5 and hence for electrically conductively contacting the two busbars 5 to the conductive coating layer 4 is created.

[0068] In the example shown, the reflective layer 6 comprises a reflective portion 6.1 being printed onto the outer face I of the outer glass pane 1 at least in a region of the underlying two busbars 5, SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0069] 11 thereby covering each of the busbars 5. The reflective portion 6.1 has an average reflectivity for visible light of at least 90 % and a thickness of 60 nm. With the preferred reflectivity of the reflective portion 6.1 it becomes possible to reliably cover the underlying busbar 5. This can, for example, be advantageous with regard to the overall visual appearance of the composite pane 10. With the advantageous thickness of the reflective layer 6, the preferred reflectivity can be achieved while also ensuring that the reflective layer 6 is sufficiently durable to reliably withstand mechanical and / or abrasive loads such as wiper blades wiping across the reflective layer 6.

[0070] Fig. 2 shows an enlarged plan view of the reflective layer 6 having the reflective portion 6.1 and a partially transparent portion 6.2. The reflective layer 6 has, in the reflective portion 6.1 an average reflectivity for visible light of at least 90 %. The reflective layer 6 has, in the partially transparent portion 6.2, an average reflectivity for visible light of at least 30 % and less than 90 %.

[0071] As can also be seen in Fig. 2, the average reflectivity of the partially transparent portion 6.2 of the reflective layer 6 decreases with an increase in distance from the reflective portion 6.1 of the reflective layer 6. This difference in reflectivity allows to create a visually appealing surface for covering of the busbar 5 by the reflective portion 6.1 of the reflective layer 6 and in the immediate surroundings of the busbar 5 by the partially transparent portion 6.2 of the reflective layer 6. This can, for example, be advantageous with respect to the overall visual appearance of the composite pane 10.

[0072] Fig. 3 depicts, using a flowchart, an exemplary embodiment of the production method according to the invention comprising the steps:

[0073] P1) providing a layer stack, comprising flat atop one another in this order: an outer glass pane 1 having an outer face I and an inner face II; a masking layer 9 forming the opaque masking region M; a conductive coating layer 4; a busbar 5 arranged in the opaque masking region M of the of the composite pane 10; an intermediate layer 3; and an inner glass pane 2 having an outer face III and an inner face IV;

[0074] P2) joining the layer stack by lamination;

[0075] P3) printing a reflective layer 6 comprising a reflective portion 6.1 onto the outer face I of the outer glass pane 1 , wherein the reflective portion 6.1 of the reflective layer 6 is printed onto the outer face I of the outer glass pane 1 at least in a region of the underlying busbar 5, thereby covering the busbar 5; and

[0076] P4) sintering the printed reflective layer 6 in a firing step by applying a surface temperature of at least 550 °C, preferably at least 560 °C, or 570 °C, and at most 600 °C, preferably at SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0077] 12 most 590 °C, or 580 °C, to the outer face I of the outer glass pane 1 having the printed reflective layer 6 for at least 200 s, preferably at least 250 s, or 300 s, with possible upper limits (independent thereof) of 400 s, 380 s, 360 s, or 340 s. The lamination of the layer stack with the intermediate layer 3 and the inner glass pane 2 can be done using common lamination methods. For example, so-called autoclave processes can be carried out at an increased pressure of about 10 bar to 15 bar and temperatures of 130 °C to 145 °C for about 2 hours. Alternatively, autoclave-free methods are also possible. Vacuum bag or vacuum ring processes known per se work, for example, at around 200 mbar and 80 °C to 110 °C. The layer stack can also be pressed into a composite disk in a calender between at least one pair of rollers. Systems of this kind are known for manufacturing composite panes and normally have at least one heating tunnel in front of a pressing unit. The temperature during the pressing process, for example, is between 40 °C and 150 °C. Combinations of calendering and autoclave processes have proven particularly effective in practice. Alternatively, vacuum laminators can be used. These consist of one or more heatable and evacuable chambers in which the outer and inner panes are laminated in about 60 minutes at reduced pressures of 0.01 mbar to 800 mbar and temperatures of 80 °C to 170 °C.

[0078] SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT

[0079] 13

[0080] Reference numerals

[0081] 1 outer glass pane

[0082] 2 inner glass pane

[0083] 3 intermediate layer

[0084] 4 conductive coating layer

[0085] 5 busbar

[0086] 6 reflective layer

[0087] 6.1 reflective portion of reflective layer 6

[0088] 6.2 partially transparent portion of reflective layer 6

[0089] 9 masking layer

[0090] 10 composite pane

[0091] 10.1 first side edge of composite pane 10

[0092] 10.2 second side edge of composite pane 10

[0093] 10.3 third side edge of composite pane 10

[0094] 10.4 fourth side edge of composite pane 10

[0095] I outer face of outer glass pane 1

[0096] 11 inner face of outer glass pane 1

[0097] I I I outer face of inner glass pane 2

[0098] IV inner face of inner glass pane 2

[0099] M opaque masking region

[0100] D transparent through-vision region

[0101] Uopower source

[0102] X-X' section line

Claims

SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT14Claims1 . Composite pane (10) with an opaque masking region (M) and a transparent through-vision region (D), comprising flat atop one another in this order:- a reflective layer (6) comprising a reflective portion (6.1);- an outer glass pane (1) having an outer face (I) and an inner face (II);- a masking layer (9) forming the opaque masking region (M);- a conductive coating layer (4);- a busbar (5) arranged in the opaque masking region (M) of the of the composite pane (10);- an intermediate layer (3); and- an inner glass pane (2) having an outer face (III) and an inner face (IV), wherein- the reflective portion (6.1) of the reflective layer (6) is printed onto the outer face (I) of the outer glass pane (1) at least in a region of the underlying busbar (5), thereby covering the busbar (5), and- the reflective layer (6) has, in the reflective portion (6.1), an average reflectivity for visible light of at least 90 %.

2. Composite pane (10) according to claim 1 , wherein the reflective layer (6) has, at least in the reflective portion (6.1), a thickness of 10 nm to 80 nm.

3. Composite pane (10) according to claim 1 or 2, wherein the reflective layer (6) further comprises a partially transparent portion (6.2), wherein the reflective layer (6) has, in the partially transparent portion (6.2), the average reflectivity for visible light of at least 30 % and less than 90 %.

4. Composite pane (10) according to claim 3, wherein the average reflectivity of the partially transparent portion (6.2) of the reflective layer (6) decreases with an increase in distance from the reflective portion (6.1) of the reflective layer (6).

5. Composite pane (10) according to one of claims 1 to 4, wherein the reflective layer (6) contains metal oxide, and wherein the metal oxide is preferably selected from titanium oxides, silicon oxides, zirconium oxides, tin oxides, zinc oxides, aluminium oxides, indium oxides and transition metal oxides.SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT156. Composite pane (10) according to one of claims 1 to 5, wherein the conductive coating layer (4) covers at least 90 % of the inner face (II) of the outer glass pane (1).

7. Composite pane (10) according to one of claims 1 to 6, wherein the conductive coating layer (4) covers at most 95 % of the masking layer (9).

8. Method for producing a composite pane (10) according to one of claims 1 to 7, comprising the steps of: a) providing a layer stack, comprising flat atop one another in this order:- an outer glass pane (1) having an outer face (I) and an inner face (II);- a masking layer (9) forming the opaque masking region (M);- a conductive coating layer (4);- a busbar (5) arranged in the opaque masking region (M) of the of the composite pane (10);- an intermediate layer (3); and- an inner glass pane (2) having an outer face (III) and an inner face (IV); b) joining the layer stack by lamination; and c) printing a reflective layer (6) comprising a reflective portion (6.1) onto the outer face (I) of the outer glass pane (1), wherein- the reflective portion (6.1) of the reflective layer (6) is printed onto the outer face (I) of the outer glass pane (1) at least in a region of the underlying busbar (5), thereby covering the busbar (5), and- the reflective layer (6) has, in the reflective portion (6.1), an average reflectivity for visible light of at least 90 %.

9. Method according to claim 8, wherein, preferably prior to step a), the masking layer (9) is printed onto the inner face (II) of the outer glass pane (1) using a screen printing process and / or the reflective layer (6) is printed onto the outer face (I) of the outer glass pane (1) using a digital printing process or a 3D-printing process.

10. Method according to claim 9, wherein after printing of the masking layer (9), the conductive coating layer (4) is applied to the inner face (II) of the outer glass pane (1), thereby covering the opaque masking region (M) and the transparent through-vision region (D) of the composite pane (10) at least partially.SAINT-GOBAIN SEKURIT FRANCE 2024353- WO-PCT1611. Method according to one of claims 8 to 10, further comprising the step of: e) sintering the printed reflective layer (6) in a firing step by applying a surface temperature of at least 550 °C and at most 600 °C to the outer face (I) of the glass pane (1) having the printed reflective layer (6) for at least 200 s and at most 400 s.

12. Use of a composite pane (10) according to one of claims 1 to 7 as glazing for a motor vehicle, preferably as windscreen, sunroof, and / or rear window.

Images