Glass article, its production process and automotive glazing including such a glass article

Abstract

Glass article, its production method, and automotive glazing comprising such a glass article. The invention relates to a glass article comprising: a glass substrate, and a first opaque layer covering at least partially a surface of the glass substrate and comprising at least one glass frit and at least one pigment, said glass article being intended to be positioned in the vicinity of at least one body panel of the vehicle, said at least one pigment being selected so that the glass article has a colorimetric appearance similar to the body panel. The invention also relates to a method for producing this glass article, comprising a step of depositing the first layer onto the glass substrate. Finally, the invention relates to automotive glazing comprising said glass article. Figure for the abstract: None

Description

Title of the invention: Glass article, its method of production and automotive glazing comprising such a glass article. Prior art

[0001] The invention relates to the field of glazing, in particular glazing for motor vehicles, for example windscreens, rear windows, side windows, quarter windows or roofs.

[0002] Automotive glazing must meet a large number of requirements, in terms of both safety and comfort.

[0003] Such glazings are often monolithic glazings, comprising a single sheet of thermally tempered glass.

[0004] Alternatively, and to improve safety as well as acoustic comfort, an increasing number of glazing units are laminated glazing units, that is, glazing units in which two sheets of glass are bonded together by means of a lamination interlayer. This interlayer helps to hold glass fragments together in the event of breakage, but also provides other functionalities, particularly in terms of burglary resistance and improved acoustic properties.

[0005] Layers of enamel, normally black and opaque, are often deposited on part of the glazing, generally in the form of a peripheral strip intended to protect against ultraviolet radiation the polymer seals used to fix and position the glazing in the body openings. They also serve to conceal said seals as well as other elements located on the glazing such as electrical connections or collector strips, intended to collect electricity.

[0006] An enamel is a mineral layer formed by firing an enamel composition comprising a glass frit, in particular bismuth borosilicate glass, and pigments.

[0007] In an effort to differentiate vehicles through their design, car manufacturers are also looking for original decorations, particularly decorations visible from the outside of the vehicle, without compromising safety or the occupants' lighting and thermal comfort. Decorations that create a smooth transition zone between the bodywork and the visible view are especially sought after.

[0008] It is known in particular from document WO 2023 / 208956 Al to use dichroic materials for their property of reflecting incident light radiation into reflected radiation of different wavelengths, making it possible to create a smooth transition zone between the bodywork and the view.

[0009] In the field of building, it is also known, for example from document WO 2017 / 191655 Al, to use reflective enamelled layers for aesthetic purposes. Description of the invention

[0010] The present invention therefore proposes, in order to obtain decorations enabling the creation of a smooth transition zone between the bodywork and the view in the field of automotive glazing, to implement such materials.

[0011] To describe such a transition, we speak of a “seamless” effect.

[0012] To this end, and according to a first aspect, the invention relates to a glass article including: • a glass substrate, and • a first opaque layer covering at least partially a surface of the glass substrate and comprising at least one glass frit and at least one pigment, said glass article being intended to be positioned in the vicinity of at least one bodywork element of the vehicle

[0013] characterized in that said at least one pigment is selected so that the glass article has a colorimetric appearance analogous to the bodywork element.

[0014] In said glass article, different colours are obtained depending on the pigment(s) used. The colouring, and therefore the pigments used, are chosen according to the colour of the bodywork with which the "seamless" effect is desired.

[0015] Since the first layer is opaque, i.e., has zero light transmission, the glass article therefore also has zero light transmission in the areas covered by said first layer.

[0016] In a particular embodiment, the first layer corresponds to an enamel, comprising a glass frit, at least one pigment, and an organic medium before firing, and then at least one pigment and a vitreous matrix obtained by melting the glass frit after firing. The term "enamel" refers to the layer both before and after firing. Enamels are typically obtained by firing above 500 °C.

[0017] The glass frit and / or the glass matrix is ​​preferably made of zinc borosilicate and / or bismuth glass. Preferably, the glass frit and / or the glass matrix is ​​zinc borosilicate.

[0018] In a particular embodiment, the first layer comprises 5% to 15% by weight, in particular 7% to 13% by weight, and preferably 10% by weight of pigment, relative to the total weight of the first layer.

[0019] In a particular embodiment, the first layer comprises less than 75%, in particular less than 50% and preferably less than 25% by weight of black pigment.

[0020] In a particular embodiment, the first layer comprises less than 5%, in particular less than 2%, preferably less than 1% by weight of cadmium and / or lead; better, the first layer is free of lead and / or cadmium.

[0021] A layer according to this embodiment is preferred when a layer stacking as described below is used. Such a layer is commercially available, for example, in the Ferro 140 Series range.

[0022] In a particular embodiment, the first layer has a thickness of 1 pm to 100 pm, in particular from 10 pm to 80 pm and preferably from 15 pm to 50 pm.

[0023] In particular, said first layer makes it possible to obtain, by its diffuse aspect when observed through the glass substrate, a colorimetric aspect, that is to say colorimetric coordinates (L*, a*, b*), analogous to the bodywork element in the vicinity of which the glass article according to the invention is intended to be positioned within the vehicle.

[0024] The Lab* color space, also known as CIELAB or CIE 1976, was defined by the International Commission on Illumination (CIE) in 1976. It is designed to represent color more perceptually uniformly than other color spaces, such as RGB or CMYK. This means that colors that are close in the Lab* space are also perceived as being close in color. The Lab* color space is based on three dimensions: • Brightness (L*): This dimension represents the lightness or darkness of a color. An L* value of 0 corresponds to black and an L* value of 100 corresponds to white. • Red-green (a*): This dimension represents the amount of red or green in a color. A value of a* = 0 corresponds to a neutral gray, positive values ​​of a* represent red, and negative values ​​of a* represent green. • Yellow-blue (b*): This dimension represents the quantity of yellow or blue blue in a color. A value of b* = 0 corresponds to a neutral grey, positive values ​​of b* represent yellow and negative values ​​of b* represent blue.

[0025] It thus appears that a glass article according to the invention has colorimetric coordinates (L*, a*, b*) close to the bodywork element in the vicinity of which it is intended to be positioned.

[0026] A parameter for evaluating the colorimetric proximity of two objects, here the glass article according to the invention and the bodywork element in the vicinity of which it is intended to be positioned, is the colorimetric difference AE, expressed by the following equation:

[0027] [Math.sl] I 5 ô ~ AE = + A«*" + Aè

[0028] where AL*, Aa* and Ab* correspond respectively to the differences between the colorimetric coordinates as defined in this text of the glass article according to the invention and said bodywork element.

[0029] The colorimetric coordinates of the glass article according to the invention and of the bodywork element in the vicinity of which it is intended to be positioned are generally considered close for an AE less than or equal to 10, in particular less than or equal to 5 and preferably less than or equal to 2.5. It is then said that the colorimetric aspect of the glass article is analogous to the bodywork element.

[0030] In particular, a glass article according to the invention and a bodywork element having an AE of less than 2.3 can be considered to have the same colorimetric appearance.

[0031] The first layer of a glass article according to the invention can substantially cover an entire surface of the glass substrate.

[0032] In a particular embodiment, said first layer is deposited directly in contact with the glass substrate.

[0033] In another particular embodiment, a stack of layers is arranged between the glass substrate and said first layer.

[0034] According to this embodiment, the glass substrate can be partially or completely covered by said stack of layers.

[0035] Similarly, the first layer may partially or completely cover the stack of layers.

[0036] Said layer stack exhibits a light reflection observed on the substrate side, referred to as Rg, of 10 to 40%, and in particular of 15 to 35%. This reflection is measured according to standard EN 410.

[0037] Thus, in a preferred embodiment of the invention, the glass article according to the invention comprises a stack of layers, covering at least partially the surface of the glass substrate and being at least partially covered by the first layer, the whole of the glass substrate and the stack exhibiting a light reflection observed on the substrate side RG of 10 to 40% and in particular of 15 to 35%.

[0038] Said embodiment has the advantage, thanks to the stacking of layers and its light reflection, of allowing a greater reflection of light radiation, which contributes to the desired seamless effect.

[0039] In particular, said stacking of layers makes it possible to obtain, by its specular aspect when observed through the glass substrate, a colorimetric aspect, that is to say colorimetric coordinates (L*, a*, b*), analogous to the bodywork element in the vicinity of which the glass article according to the invention is intended to be positioned within the vehicle.

[0040] A person skilled in the art will therefore readily understand that a stack of layers suitable for the present invention exhibits non-zero light transmission. In particular, said stack may exhibit a light transmission of at least 10% and preferably of at least 20%.

[0041] In this embodiment, the first layer advantageously fulfills a mechanical protection role, in particular an anti-scratch role, of the stack of layers.

[0042] A stack of layers suitable for the present invention is advantageously a stack acting on solar radiation, in particular intended for thermal insulation and / or solar protection, i.e. contributing to the thermal comfort of the vehicle.

[0043] Such stacks are described for example for applications in the field of building, in document EP 1 218 307 Bl.

[0044] In particular, said stack of layers comprises at least one functional layer based on a partially or fully nitrided metal. Said metal is selected from niobium, tantalum, and zirconium, preferably niobium. Said functional layer is surmounted by at least one overlayer based on aluminum nitride, aluminum oxynitride, silicon nitride, or silicon oxynitride, or a mixture of at least two of these compounds.

[0045] In particular, the stack further comprises, between the glass substrate and the functional layer, at least one sublayer of transparent dielectric material, in particular selected from aluminium nitride, aluminium oxynitride, silicon nitride, silicon oxynitride, or a mixture of at least two of these compounds.

[0046] Preferably, the stack consists of a silicon nitride sublayer, a niobium or niobium nitride functional layer and a silicon nitride overlayer.

[0047] In this text, the term "functional layer" means the layer(s) of the stack which give the stack the essential thermal properties, as opposed to the other layers, generally made of dielectric material, which have the role of providing chemical or mechanical protection to the functional layers, an optical role, an adhesion layer role, etc.

[0048] In a particular embodiment, a stack of layers suitable for the invention comprises: • a functional layer with a thickness of 5 to 50 nm, preferably 8 to 40 nm; and • an overlayer with a thickness of 5 to 120 nm, preferably 7 to 90 nm.

[0049] In a glass article according to the invention, the stacking of layers can substantially cover an entire surface of the glass substrate.

[0050] In a glass article according to the invention, the thickness of the first layer can be from 1 pm to 100 pm, in particular from 10 pm to 80 pm and preferably from 15 pm to 50 pm.

[0051] A stack of layers as defined in this text advantageously supports the heat treatments to which glass articles are usually subjected in the field, for example tempering, bending or firing of an enamel.

[0052] A glass substrate suitable for the invention can be clear or tinted in mass.

[0053] Clear lenses suitable for the invention are, for example, marketed by the company Saint-Gobain Glass France under the reference Planiclear.

[0054] Mass-tinted glass suitable for the invention is, for example, marketed by the company Saint-Gobain Glass France under the reference Parsol, in particular Parsol Green and Parsol Sapphire Blue.

[0055] According to another aspect, the present invention relates to a method for obtaining a glass article as defined above, comprising • Optionally, a magnetron deposition step of the layer stack on at least a portion of the glass substrate surface, and • a step of depositing the first layer, where appropriate on the stack of layers, and / or on at least part of the surface of the glass substrate.

[0056] In one embodiment of the invention, the first layer deposition step is carried out by screen printing, by digital printing and / or by roller application, preferably by digital printing.

[0057] Digital printing deposition makes it possible, in particular, to obtain a gradient between the edge and the center of the substrate. Thus, the edge can have a colorimetric appearance particularly close to the bodywork element near which it is intended to be positioned, while towards the center, the amount of first layer deposited being less, the colorimetric appearance approaches that of a glass article without said first layer. This gradient contributes advantageously to the desired seamless effect.

[0058] A screen printing process comprises depositing, notably using a squeegee, a paste-like liquid onto a substrate through the mesh of a screen printing screen. The screen mesh is blocked in the portion corresponding to the areas of the substrate that must remain exposed, so that the paste can only pass through the screen in The areas to be printed are defined according to a predefined pattern. The selective closure of the mesh is therefore done according to the negative of the pattern to be printed.

[0059] This selective sealing is generally achieved by applying a photocurable resin to the screen and then by exposing the parts of the screen to be sealed to ultraviolet radiation.

[0060] Selective exposure is for example achieved using a slide comprising a transparent support, typically made of polyester, coated with an opaque ultraviolet ink deposited according to the pattern to be printed.

[0061] The mesh of the screen is chosen according to the viscosity and surface tension of the paste as well as according to the desired thickness for the resulting layer of the screen printing deposition.

[0062] In a particular embodiment, a method according to the invention further comprises, after the steps of depositing the stack of layers and the first layer, a step of depositing, in particular of screen printing, a solution comprising a phosphate salt on at least a part of the stack of layers not covered by the first layer.

[0063] Said solution is in particular deposited after a drying step of the glass article.

[0064] Said solution can be deposited on the entire glass article or on at least a portion of the glass article not covered by the first layer. In particular, the solution is deposited on a portion of the glass article covered by the stack of layers suitable for the invention.

[0065] Such a solution is described, for example, in document EP 3 826 972 B1 and allows layers (in the context of the present invention: the stack of layers suitable for the invention and / or any layer other than the first layer) to be dissolved in order to obtain a finish corresponding to the glass substrate after a baking step. This finish may conform to a pattern applied during the deposition of the solution.

[0066] According to yet another of its aspects, the present invention relates to an automotive glazing comprising a glass article according to the invention.

[0067] In a glazing according to the invention, the surface on which the first layer is spread is called the "enameled area".

[0068] The enameled area is in particular in the form of a peripheral band. That is to say, a band closed upon itself which, from each point of the glass article according to the invention, extends towards the interior of the glass article over a certain width, typically between 1 and 20 cm.

[0069] The remaining part of the automotive glazing according to the invention, called the "non-enameled area", is generally uncoated.

[0070] Alternatively, it can be coated with a stack of thin films, for example including a low emissivity layer, in particular based on silver or on a transparent electro-conductive oxide such as indium tin oxide or doped tin or zinc oxides.

[0071] In a particular embodiment, the automotive glazing according to the invention is laminated or tempered glazing.

[0072] When the glazing according to the invention is laminated or tempered, the first layer and the stack of layers, when present, can be deposited on the inner face of this glazing.

[0073] The term "inner face" refers to any face of a glass pane in the glazing, positioned opposite the passenger compartment of a vehicle. For example, for tempered glass, this may be the face in contact with the interior of the vehicle's passenger compartment, or, in the case of laminated glass, the inner face of the outer pane, that is to say, the one located on the side of the lamination interlayer.

[0074] When the automotive glazing according to the invention is tempered, the tempering of the latter is advantageously carried out simultaneously with the baking of the first layer.

[0075] The automotive glazing according to the invention can be curved.

[0076] The glass substrate on which the first layer and the stack of layers are deposited is generally flat. It is then preferably curved and thus has a curved shape in the automotive glazing according to the invention.

[0077] The curvature of the glazing can increase the impression of "seamlessness" for an observer. Indeed, compared to flat glass or glass with a less pronounced curvature, observation from the same point results in a greater range of viewing angles and thus a greater range of glazing colours, which vary according to the viewing angle due to the reflection made possible by the stacking of thin layers.

[0078] When the automotive glazing according to the invention is curved, the curvature of the latter is advantageously carried out simultaneously with the baking of the first layer.

[0079] The glazing according to the invention may include an enamelled area comprising 2 to 25%, in particular 3 to 20% and preferably 5 to 15% of the surface of its face coated by the first layer and the stacking of layers.

Claims

Demands

1. A glass article for a motor vehicle comprising: • a glass substrate, and • a first opaque layer covering at least partially a surface of the glass substrate and comprising at least one glass frit and at least one pigment, said glass article being intended to be positioned in the vicinity of at least one bodywork element of the vehicle characterized in that said at least one pigment is selected so that the glass article has a colorimetric appearance similar to the bodywork element.

2. Glass article according to the preceding claim, wherein the first layer substantially covers an entire surface of the glass substrate.

3. Glass article according to any one of the preceding claims, further comprising a stack of layers, covering at least partially the surface of the glass substrate and being at least partially covered by the first layer, the whole of the glass substrate and the stack having a light reflection observed on the substrate side RG of 10 to 40% and in particular of 15 to 35%.

4. A glass article according to the preceding claim, wherein the layer stack comprises at least one functional layer based on a partially or wholly nitrided metal, said metal being selected from niobium, tantalum, and zirconium, preferably niobium, said functional layer being overlaid with at least one overlayer based on aluminum nitride, aluminum oxynitride, silicon nitride, or silicon oxynitride, or a mixture of at least two of these compounds; in particular, the stack further comprises, between the glass substrate and the functional layer, at least one sublayer of transparent dielectric material, in particular selected from aluminum nitride, aluminum oxynitride, silicon nitride, silicon oxynitride, or a mixture of at least two of these compounds; preferably, the stack consists of a sub- silicon nitride layer, niobium or niobium nitride functional layer and silicon nitride overlayer.

5. Glass article according to the preceding claim, wherein the layer stack comprises: • a functional layer of thickness from 5 to 50 nm, preferably from 8 to 40 nm; and • an overlayer of thickness from 5 to 120 nm, preferably from 7 to 90 nm.

6. Glass article according to any one of claims 3 to 5, wherein the stacking of layers substantially covers an entire surface of the glass substrate.

7. Glass article according to any one of the preceding claims, wherein the first layer comprises less than 75%, in particular less than 50% and preferably less than 25% by weight of black pigment.

8. Glass article according to any one of the preceding claims, wherein the first layer comprises less than 5%, in particular less than 2%, preferably less than 1% by weight of cadmium and / or lead; better, the first layer is free of lead and / or cadmium.

9. Glass article according to any one of the preceding claims, wherein the first layer comprises from 5% to 15% by weight, in particular from 7% to 13% by weight, and preferably 10% by weight of pigment, relative to the total weight of the first layer.

10. Glass article according to any one of the preceding claims, wherein the first layer has a thickness of from 1 pm to 100 pm, in particular from 10 pm to 80 pm and preferably from 15 pm to 50 pm.

11. Glass article according to any one of the preceding claims, wherein the glass substrate is clear or tinted throughout.

12. A method for obtaining a glass article according to any one of the preceding claims, comprising: • optionally, a magnetron deposition step of the layer stack on at least a portion of the surface of the glass substrate, and • a step of depositing the first layer, where appropriate on the stack of layers, and / or on at least part of the surface of the glass substrate.

13. A method according to the preceding claim, characterized in that the first layer deposition step is carried out by screen printing, by digital printing and / or by roller application, preferably by digital printing.

14. A method according to any one of claims 12 to 13, further comprising, after the steps of depositing the layer stack and the first layer, a step of depositing, in particular by screen printing, a solution comprising a phosphate salt on at least a part of the layer stack not covered by the first layer.

15. Automotive glazing, characterized in that it comprises a glass article according to any one of claims 1 to 11, said glazing being laminated or tempered.

16. Automotive glazing according to the preceding claim, wherein the first layer and the layer stacking when present, is (are) arranged on the inner face.