Glass sheet comprising glazed regions

Abstract

The invention relates to a material comprising a glass sheet (10), one face of which comprises a glazed area (2), such that in the glazed area (2), the glass sheet (10) is coated with an opaque mineral layer (12) and under at least a portion of the opaque mineral layer (12) is coated with a non-glazed transparent mineral coating (14), the transparent mineral coating (14) comprises, in the glazing area (2), a first area (Z1) in which the transparent mineral coating (14) has a first thickness (e1) and a second area (Z2) in which the transparent mineral coating (14) has a second thickness (e2), the first and second thicknesses being different.

Description

[0001] The present invention relates to assembled glass, in particular in the field of assembled glass for buildings or transport vehicles.

[0002] Glass sheets are known to be coated on all or part of their surface with an opaque mineral layer, in particular an opaque enamel layer. Enamel is a layer comprising a vitreous or vitrocrystalline binder and pigments, which is obtained by depositing a fluid enamel composition comprising frit, pigments and an organic medium and subsequent firing. The enamel coating is generally decorative, but can also provide masking and protection functions, such as resistance to ultraviolet radiation.

[0003] The object of the present invention is to provide an enameled assembled glass having a decorative appearance, which is viewed from the face opposite to the face carrying the opaque layer and which can be manufactured simply and economically.

[0004] To this end, the object of the present invention is a material comprising a glass sheet, one face of which comprises an enameled zone, such that in said enameled zone, the glass sheet is coated with an opaque mineral layer and below at least a part of said opaque mineral layer is coated with a non-enameled transparent mineral coating, said transparent inorganic coating comprising a first zone and a second zone in said enameled zone, in said first zone, said transparent inorganic coating has a first thickness, and in said second zone, said transparent inorganic coating has a second thickness, said first and second thicknesses being different.

[0005] Another object of the present invention also lies in a method of obtaining such a material, which comprises depositing a non-enameled transparent mineral coating on one face of a glass sheet and in a so-called enameled zone, and then depositing an opaque mineral layer on this transparent mineral coating, said transparent mineral coating comprising a first zone and a second zone in said enameled zone, in said first zone, said transparent mineral coating has a first thickness, and in said second zone, said transparent mineral coating has a second thickness, said first and second thicknesses being different.

[0006] Another object of the present invention also lies in an assembled glass comprising a material according to the present invention.

[0007] The inventors have been able to demonstrate that the presence of the transparent mineral coating and the presence of a plurality of zones in which the transparent mineral coating has different thicknesses make it possible to form a decoration visible from the face opposite to the glazed face. The reflective appearance of the enamel is adjusted by the thickness of the underlying coating, and the contrast between the different zones creates a decorative effect. Moreover, this decoration is obtained very simply using a single opaque mineral layer (in particular enamel) and possibly after a single firing step.

[0008] The glass sheet is preferably made of soda-lime glass. Advantageously, it is obtained by the float process. Nevertheless, other glass compositions are possible, such as compositions of the borosilicate or aluminosilicate type.

[0009] The glass sheet can be made of clear glass or preferably tinted glass, such as green, grey, bronze or blue. In the case of tinted glass, the chemical composition of the glass sheet advantageously contains from 0.5 to 2.5% by weight of iron oxide. It can also contain other colorants, such as cobalt oxide, chromium oxide, nickel oxide, erbium oxide or selenium. In the case of clear glass, the chemical composition of the glass sheet advantageously contains from 0.01 to 0.15% by weight of iron oxide.

[0010] The glass sheet is preferably from 0.7 to 19 mm thick, particularly from 1 to 6 mm, or even 2 and 4 mm. The glass sheet preferably has a surface area of at least 1 m 2 .

[0011] The glass sheet can be flat or curved. During the deposition stage of the transparent mineral coating and the opaque mineral layer, it is generally flat. However, certain deposition techniques, especially by digital printing, are capable of depositing these coatings on curved sheets. In the case of glazing for vehicles, especially motor vehicles, it is preferably subsequently curved and thus has a curved shape in the final glazing.

[0012] The term "glazed area" generally refers to the area covered by the opaque mineral layer, as described in detail below, which is most often but not necessarily an enamel layer.

[0013] Depending on the intended application, the glazed area can cover all or part of the surface of the glass sheet. It can cover the entire surface of the glass sheet, for example in the case of spandrel glasses. Or, it can cover only a part of the surface of the glass sheet, particularly from 2 to 80%, or even from 5 to 50% or from 10 to 25%. In the case of vehicles, especially motor vehicles, the glazed area is preferably in the form of a peripheral strip. "Peripheral strip" is intended to mean a self-closed strip that extends from each point on the periphery of the glass sheet towards the interior of the glass sheet by a certain width (generally between 1 and 20 cm). Such a peripheral strip is designed to hide and protect the polymer gaskets used to fix and position the glazing in the bodywork bays, as well as various mechanical or electrical components (heating circuits, rear-view mirror bases, sensors or cameras, etc.) from ultraviolet radiation.

[0014] In one embodiment, the transparent mineral coating is in contact with the glass sheet. In this case, the glass sheet is preferably coated only with this coating and the opaque mineral layer in the glazed area.

[0015] Alternatively, other layers or layer stacks can be inserted between the glass sheet and the transparent mineral coating. For example, it can involve a thin layer or a stack of thin layers comprising at least one functional layer, such as a conductive layer or a low-emissivity layer (especially based on silver or based on transparent conductive oxides (TCO), such as indium tin oxide or doped tin oxide or zinc oxide). In particular, such layers or stacks can perform heating (defrosting, demisting) and / or daylight control and / or heat insulation functions.

[0016] The opaque mineral layer preferably contacts the transparent mineral coating.

[0017] The transparent mineral coating is present below at least a part of the opaque mineral layer. It can be present below the entire opaque mineral layer, i.e., in the entire glazed area. Alternatively, it can be present below only a part of the opaque mineral layer, for example, below 2 to 80% of the opaque mineral layer, especially below 10 to 60%. This is the case, for example, when the purpose of the transparent mineral coating is to form a decoration in only a part of the glazed area.

[0018] In both of the above cases, when there is an unglazed area, the transparent mineral coating can also be present on all or part of the unglazed area. It can then be present on the entire glass sheet. This is the case, for example, when the transparent mineral coating has another function that is also useful in the clear vision of the assembled glass, such as an optical function, especially an anti-reflection function. Alternatively, the transparent mineral coating can be absent from the unglazed area.

[0019] The presence of the transparent mineral coating changes the appearance of the enamel as seen in the reflection through the glass sheet. Obviously, this appearance varies according to the thickness of the coating. The presence of multiple areas with different thicknesses of the coating thus makes it possible to obtain different appearances in each area, making it possible to obtain a decoration.

[0020] The decoration can be of any kind: various patterns, such as geometric patterns, logos, etc. For example, the decoration can create a transition zone between the body of the vehicle and the clear vision of the assembled glass.

[0021] To achieve an attractive appearance, the transparent mineral coating preferably has a high light transmittance. The transparent mineral coating preferably enables a light transmittance of at least 70%, especially at least 80%, or even at least 88% when deposited on a clear glass sheet. Clear glass is glass whose chemical composition includes iron oxide in a proportion of 0.05 to 0.12% by weight as the only colorant. An example of clear glass is the glass sold by the applicant glass.

[0022] The transparent mineral coating is preferably colorless (ie untinted). In particular, the transmission colorimetric coordinates a* and b* (illuminant D65, CIE-1964 observer) of the transparent mineral coating viewed through a clear glass plate are preferably between 0 and 5, in particular between 0 and 2, or even between 0 and 1.

[0023] In one embodiment, the transparent mineral coating comprises a single layer. The presence of regions of different thickness is then obtained by locally varying the thickness of the single layer during deposition.

[0024] In another embodiment, the transparent mineral coating comprises a plurality of superimposed layers, in particular two, three or four layers, at least in the first region or in the second region. In this case, the thickness of the coating in one region corresponds approximately to the sum of the thicknesses of the individual layers forming the coating in that region. The thickness of the coating may not completely correspond to the sum of the thicknesses of the individual layers when the deposition of one layer causes a slight reduction in the thickness of the layer below. These layers are generally of the same chemical nature, but may alternatively have different chemical properties. Regions of different thicknesses are then obtained by depositing different numbers of layers in each region. In this way, the number of layers forming the coating in the first region is different from the number of layers forming the coating in the second region. For example, the coating can be formed by a single layer in the first region and by two layers in the second region, the thickness of the coating in the second region therefore being different from the thickness of the coating in the first region, usually twice if the layers have the same thickness.

[0025] Regardless of the embodiment, the number of regions corresponding to different thicknesses is not limited to two. Thus, in addition to the first and second regions, the transparent mineral coating may also have a third region, wherein the coating has a third thickness different from the first and second thicknesses. In general, the transparent mineral coating may include N regions Z x (N is at least 2, and x is 1 to N), for any x different from y, the transparent mineral coating is in region Z x The thickness of e x Unlike transparent mineral coatings in Zone Z y The thickness of e y For simplicity, N is preferably at most 10, still better at most 8, and even at most 5.

[0026] The term "area" refers to an area that lies in the plane of the coating.

[0027] The reflective appearance of the opaque layer as seen through the glass sheet may vary depending on the thickness of the transparent mineral coating and its refractive index.

[0028] The thickness of the mineral coating in each region (first, second, even third and more) is preferably between 30 and 1000 nm, particularly between 50 and 500 nm, or even between 60 and 300 nm.

[0029] Preferably, the ratio between the second thickness and the first thickness is at least 1.2, particularly at least 1.5, or even at least 1.8. It is usually not greater than 4, or even not greater than 3. Generally, when the transparent mineral coating comprises N regions Z x then, the ratio between the thickness in region Z x and the thickness in region Z x-1 is preferably at least 1.2, particularly at least 1.5, or even at least 1.8, and is usually at most 4 or at most 3.

[0030] The refractive index of the transparent mineral coating (usually for a wavelength of 550 nm) is preferably between 1.3 and 2.4, particularly between 1.4 and 2.0. The refractive index as well as the thickness of the transparent mineral coating can affect the perceived color. If the transparent mineral coating is formed of multiple layers of different chemical nature, the refractive index of the coating corresponds to the average value of the refractive indices of each layer weighted by the thickness of each layer.

[0031] The transparent mineral coating is preferably based on oxides, nitrides or oxynitrides of one or more elements selected from Si, Zr, Ti, Zn, Sn and Al. It is preferably based on oxides of one or more elements selected from Si, Zr, Ti, Zn, Sn and Al. Preferred oxides are oxides of silicon, zirconium and titanium. Preferably, the transparent mineral coating is based on silicon oxide, which particularly consists of silicon oxide. The choice of elements allows the adjustment of the refractive index of the coating. Silicon oxide (also known as silica) has a refractive index of approximately 1.4.

[0032] The transparent mineral coating is preferably a sol-gel coating. In this case, the coating is deposited using the sol-gel method. The sol-gel coating is preferably based on silicon oxide or consists of silicon oxide. The term "based on" is understood to mean that the coating contains at least 50 wt% of silicon oxide. It may contain other oxides, such as oxides of titanium or zirconium, to vary the refractive index of the coating.

[0033] The sol-gel method is a method in which a sol containing the precursors of the coating to be produced is deposited on a glass plate by various means, such as spraying, curtain coating, laminar coating, roll, screen printing, inkjet deposition, etc. Screen printing or inkjet deposition is preferred here because it allows the easy deposition of the coating only in the desired regions.

[0034] The sol preferably contains an organometallic precursor of the coating to be produced, such as tetraethyl orthosilicate (TEOS). This coating is then usually dried and annealed to densify it before depositing the enamel layer. The annealing is preferably carried out during the same step as the enamel firing, usually during the bending and / or tempering of the glass sheet.

[0035] Alternatively, the coating can be deposited by PVD or CVD (chemical vapor deposition) methods, such as sputtering, or by plasma-enhanced chemical vapor deposition (PECVD) (possibly at atmospheric pressure (APPECVD)). A mask can then be used to apply the coating only in the desired areas. However, these methods are more complex than screen printing or inkjet printing.

[0036] If the transparent mineral coating contains a plurality of stacked layers at least in the first region or the second region, the coating deposition includes successive steps of depositing the individual layers. For example, different screen printing screens can be used for successive screen printing passes. A drying step is preferably carried out between two successive layer deposition steps, usually at a temperature between 120 and 200 °C.

[0037] When the transparent mineral coating contains a single layer, the coating deposition includes only one deposition step. In the case of screen printing deposition, regions with different thicknesses can be obtained in one step by various means, particularly as described in application W2018 / 229449.

[0038] Generally speaking, the opaque mineral layer is a layer containing pigments in a mineral binder. The opaque mineral layer is preferably enamel or silicate paint.

[0039] The coating is opaque, which means that the light transmission coefficient in the glazed area is less than 0.1%, especially zero.

[0040] At least one pigment, and particularly each pigment, is preferably based on oxides or sulfides of iron, chromium, copper, cobalt, titanium, and / or manganese. The color of the pigment, and thus the color of the opaque mineral layer, is not limited: white, black, blue, red, yellow, green, etc. In the case of vehicle glazing, especially automotive glazing, the pigment is preferably black. The opaque mineral layer is thus black and advantageously has a reflected chromaticity coordinate L* of the glazed surface of less than 5, especially less than 3. This measurement excludes specular reflection.

[0041] "Silicate paint" refers to a layer obtained from an aqueous paint composition containing pigments and an aqueous solution of an alkali metal silicate. This coating thus contains pigments bound together by a silicate binder.

[0042] The aqueous alkali metal silicate solution preferably contains at least one of sodium silicate, potassium silicate and / or lithium silicate. The aqueous alkali metal silicate solution can consist of a mixture of aqueous solutions of different alkali metal silicates, for example a mixture of at least one sodium aqueous solution and at least one potassium aqueous solution.

[0043] The paint composition preferably contains at least one mineral filler, which is particularly selected from colloidal silica, feldspar, alumina and layered fillers. The layered fillers are preferably selected from talc, mica and clay, in particular clay based on silicate or aluminosilicate, such as kaolinite, illite, montmorillonite and sepiolite. The paint composition advantageously contains a mixture of several mineral fillers.

[0044] The mineral filler and the pigment preferably have a particle size distribution (by volume) such that their d90 is less than 10 μm.

[0045] The paint composition can also contain bases, in particular alkali metal hydroxides.

[0046] The paint composition can additionally contain various additives, such as at least one dispersant, at least one defoamer, at least one thickener, at least one stabilizer and / or at least one hardener.

[0047] In the layer of the mineral paint, the weight content of the alkali metal silicate is preferably between 7% and 60%, in particular between 15 and 55%. The total weight content of the pigment and the mineral filler is preferably between 20 and 90%, in particular between 30 and 70%. The total content of the additives is preferably between 0.1 and 5%. These contents also apply to the aqueous paint composition (in this case the percentages are relative to the dry extract).

[0048] The term enamel layer refers to the layer before and after firing.

[0049] Before firing, the enamel layer contains frit, pigment and organic medium. After firing, the enamel layer contains pigment and a vitreous or glass-crystalline matrix obtained by fusing the frit. The frit and / or the vitreous matrix preferably consist of bismuth and / or zinc borosilicate.

[0050] The enamel layer is preferably obtained by screen printing a fluid enamel composition containing frit, pigment and organic medium. For this purpose, a doctor blade is particularly used to deposit the enamel composition through the apertures of the screen onto the glass plate. The apertures of the screen are blocked off in the part corresponding to the non-covered area of the glass plate so that the enamel composition can pass through the screen only in the area to be printed according to a predetermined pattern. Other deposition techniques, such as digital printing techniques (e.g. inkjet), are also possible.

[0051] Typically, the opaque mineral layer, and thus the silicate paint layer, is advantageously deposited by these different techniques, in particular by screen printing or digital printing, especially inkjet printing.

[0052] Before firing, the opaque mineral layer, especially the enamel layer, has a thickness preferably between 10 and 30 μm, especially between 15 and 25 μm. After firing, the thickness of the opaque mineral layer, especially the enamel layer, is preferably between 5 and 15 μm, especially between 7 and 13 μm.

[0053] The method according to the invention preferably comprises the step of firing the opaque mineral layer, especially the enamel layer, typically during the tempering and / or bending of the glass plate. If necessary, this step is also used to densify the sol-gel underlying layer. This step involves a temperature preferably of 550 to 720 °C. The invention thus makes it possible to manufacture the decoration in a single firing step.

[0054] In the case of the silicate paint, the coated glass plate can undergo a pre-firing step which is designed to harden the paint layer before a possible tempering and / or bending step. Mineral paints based on alkali metal silicates can generally be cured at a moderate temperature of 200 - 250 °C.

[0055] Bending can be achieved especially using gravity (the glass deforms under its own weight) or by pressing at a temperature typically of 550 to 650 °C. In the case of laminated assembled glass, the two glass plates can be bent together (this is the preferred mode) or separately. Before the bending step, the method can also include the step of pre-firing the first glass plate coated with the opaque layer at a temperature preferably between 450 and 600 °C. Such pre-firing removes the organic medium, or any organic components that may typically be present in the opaque layer, and improves the non-stick properties of the opaque layer. It is important to avoid any adhesion between the opaque layer and another glass plate or between the opaque layer and the bending tool.

[0056] The assembled glass according to the invention can comprise a single glass plate. In this case, the glass plate is preferably heat tempered. It can be hardened or annealed.

[0057] Alternatively, the assembled glass can be laminated assembled glass, in which the glass plate of the material according to the invention is adhesively bonded to another glass plate by means of a lamination intermediate layer (such as polyvinyl butyral). In this case, the glass plate is not heat tempered.

[0058] In the case of laminated assembled glass, the opaque mineral layer, especially the enamel layer, is preferably provided on face 2 or face 4, i.e., the face opposite the face facing the outside (referred to as 1) (of the vehicle or building) or the innermost face. In this case, the decoration is visible from the outside.

[0059] The assembled glass can also be a multi-layer assembled glass, for example, a double-layer or a triple-layer one, in which the glass plate made of the material according to the present invention is combined with at least one other glass plate by means of a peripheral spacer frame usually made of a metal or polymer material.

[0060] The assembled glass according to the present invention can be a (land, air or sea) vehicle assembled glass, in particular a motor vehicle assembled glass, such as a rear window, a windshield, a side window, a roof, a roof headliner or a triangular window.

[0061] The assembled glass can alternatively be a building assembled glass, for example, for a facade or a window, or a furniture or decorative assembled glass (partition wall, door, table, etc.).

[0062] The following examples illustrate the present invention without limitation.

[0063] Figure 1 Illustrates an embodiment of the present invention used in the illustrated example. More specifically, it illustrates a schematic cross-sectional view of the material according to the example. Of course, the thicknesses of the various elements are not shown to scale.

[0064] A sol-gel silica coating 14 is deposited on a part of a virgin float glass plate (sold by the applicant under the reference ). This transparent mineral coating 14 is deposited by screen printing and comprises three zones Z1 to Z3.

[0065] In the first zone Z1, the coating 14 consists of a single silica layer 141. In the second zone Z2, the coating 14 consists of two superposed silica layers (141 and 142). In the third zone Z3, the coating consists of three superposed silica layers (141, 142 and 143). In this example, the thicknesses (e1, e2 and e3) of each silica layer are substantially the same. The coating 14 is deposited in three successive screen printing steps, followed in each case by a step of drying at 160 °C for 180 seconds. The wet thickness of each layer is approximately 10 μm.

[0066] A black enamel layer 12 is deposited on the coating 14 and on the part of the glass plate 10 not coated with the coating 14. This deposition is also carried out by screen printing, and the wet enamel thickness is approximately 25 μm.

[0067] After drying (160 °C, 180 seconds), the glass plate is tempered by heating it to 690 °C and then rapidly cooling it using an air nozzle.

[0068] After tempering, a spectrophotocolorimeter is used to characterize the visual appearance as seen from the uncoated sheet side in reflection (excluding specular reflection), and the results are shown in the following table. ​

[0069] [Table 1]

[0070] Region L* a* b* Enamel only 3.7 0.1 0.4 <![CDATA[Z1]]> 4.0 0.1 -0.6 <![CDATA[Z2]]> 6.4 -0.3 -1.1 <![CDATA[Z3]]> 9.1 -0.6 -1.7

[0071] The results show that, in the case of black enamel, the areas containing the silica coating exhibit a greyer shade in reflection, and the thicker the coating, the greyer the shade. The contrast between the different areas is sufficient for the decoration to be fully visible.

Claims

1. A material comprising a glass sheet (10), one face of said glass sheet (10) comprising a glazed area (2) such that in said glazed area (2), said glass sheet (10) is coated with an opaque mineral layer (12), and a non-enameled transparent mineral coating (14) is coated under at least a part of said opaque mineral layer (12), said transparent mineral coating (14) comprising a first area (Z1) and a second area (Z2) in said glazed area (2), in said first area (Z1), said transparent mineral coating (14) has a first thickness (e1), in said second area (Z2), said transparent mineral coating (14) has a second thickness (e2), and said first and second thicknesses are different.

2. The material according to claim 1, wherein said opaque mineral layer (12) is enamel or silicate paint.

3. The material according to any one of the preceding claims, wherein said opaque mineral layer (12) is in contact with said transparent mineral coating (14).

4. The material according to any one of the preceding claims, wherein said transparent mineral coating (14) has a light transmittance of at least 70%, particularly at least 80%, when deposited on a float glass sheet.

5. The material according to any one of the preceding claims, wherein said transparent mineral coating (14) is colorless.

6. The material according to any one of the preceding claims, wherein said transparent mineral coating (14) comprises a plurality of stacked layers (141, 142, 143) at least in the first area (Z1) or the second area (Z2, Z3).

7. The material according to any one of the preceding claims, wherein the transparent mineral coating (14) comprises N regions Z x (Z1, Z2, Z3), N being at least 2 and x being from 1 to N, for any x different from y, the thickness e x of the transparent mineral coating (14) in region Z x is different from the thickness e y of the transparent mineral coating in region Z y .

8. The material according to any one of the preceding claims, wherein the thickness of said transparent mineral coating (14) in each area is between 30 and 1000 nm, particularly between 50 and 500 nm.

9. The material according to any one of the preceding claims, wherein the ratio between said second thickness (e2) and said first thickness (e1) is at least 1.2, particularly at least 1.

5.

10. The material according to any one of the preceding claims, wherein said transparent mineral coating (14) is based on oxides of one or more elements selected from Si, Zr, Ti, Zn, Sn, and Al, particularly based on silicon oxide.

11. The material according to any one of the preceding claims, wherein said transparent mineral coating (14) is a sol-gel coating.

12. A method for obtaining the material according to any one of the preceding claims, which comprises depositing a non-enameled transparent mineral coating (14) on one face of a glass sheet (10) and in a so-called glazed area (2), and then depositing an opaque mineral layer (12) on this transparent mineral coating (14), said transparent mineral coating (14) comprising a first area (Z1) and a second area (Z2) in said glazed area (2), in said first area (Z1), said transparent mineral coating (14) has a first thickness (e1), in said second area (Z2), said transparent mineral coating (14) has a second thickness (e2), and said first and second thicknesses are different.

13. The method according to the preceding claim, wherein the transparent mineral coating (14) is deposited by a sol-gel process and the opaque mineral layer (12) is deposited by screen printing or digital printing.

14. The method according to the preceding claim, wherein the transparent mineral coating (14) is deposited by screen printing or inkjet printing.

15. An assembled glass comprising at least one material according to any one of claims 1 to 11.

Images