LAMINATED GLAZING FOR VEHICLES, PARTICULARLY MOTOR VEHICLES

Abstract

A laminated glazing for a vehicle, in particular a motor vehicle, includes an exterior glass sheet adhesively bonded to an interior glass sheet by a lamination interlayer, wherein the exterior glass sheet carries a layer of a first enamel, of black color, on the periphery of its face in contact with the lamination interlayer, known as face 2, and the interior glass sheet carries on its face in contact with the lamination interlayer, known as face 3, a layer of a second enamel forming a marking and having a color other than black, located opposite the layer of the first enamel, the laminated glazing further including a polymeric seal on the face of the interior glass sheet, called face 4, opposite face 3, the seal concealing the marking.

Claims

1. A laminated glazing for a vehicle, in particular a motor vehicle, comprising an exterior glass sheet adhesively bonded to an interior glass sheet by means of a lamination interlayer, wherein the exterior glass sheet includes a first face and carries a layer of a first enamel, of black color, on a periphery of a second face in contact with the lamination interlayer, known as face 2, the second face being opposite the first face, and the interior glass sheet carries on a third face in contact with the lamination interlayer, known as face 3, a layer of a second enamel forming a marking and having a color other than black, located opposite the layer of the first enamel, said laminated glazing further comprising a polymeric seal on a fourth face of the interior glass sheet, called face 4, which is opposite the third face 3, said polymeric seal concealing said marking.

2. The laminated glazing according to claim 1, wherein the marking comprises at least one line or a plurality of patterns, located at a periphery of the interior glass sheet.

3. The laminated glazing according to claim 1, wherein the marking is adapted to form a reference point for the deposition of the polymeric seal on the fourth face.

4. The laminated glazing according to claim 1, wherein the first enamel has a colorimetric coordinate L* in reflection on the glass side lower than 10.

5. The laminated glazing according to claim 1, wherein the second enamel is white in color.

6. The laminated glazing according to claim 1, wherein the layer of second enamel coats between 0.05% and 5% of the third face of the interior glass sheet.

7. The laminated glazing according to claim 1, wherein the first and second enamels comprise a bismuth borosilicate-based glass or glass-crystalline binder.

8. The laminated glazing according to claim 7, wherein the first and second enamels comprise a same glass or glass-crystalline binder.

9. The laminated glazing according to claim 1, wherein a low-emissive or solar control coating is disposed on the third face, under the layer of the second enamel.

10. The laminated glazing according to claim 1, wherein the polymeric seal is in the form of a bead deposited on at least part of the periphery of the glazing.

11. The laminated glazing according to claim 1, wherein the polymeric seal is polyurethane-based.

12. The laminated glazing according to claim 1, which is a windshield, a roof, a rear window, or a side window, of a motor vehicle.

13. A method for manufacturing the laminated glazing according to claim 1, comprising: depositing a layer of a first enamel, of black color, on the periphery of one face of a glass sheet forming an exterior glass sheet, depositing a layer of a second enamel forming a marking and having a color other than black on one face of a glass sheet forming an interior glass sheet, then, pre-firing of the first and second enamel layers, then, bending the exterior and interior glass sheets together, said interior glass sheet being disposed on top of said exterior glass sheet, the layer of the first enamel and the layer of the second enamel facing each other, and then, laminating the exterior and interior glass sheets by means of a lamination interlayer.

14. The method according to claim 13, wherein the layer of the first enamel and the layer of the second enamel are deposited by screen-printing an enamel composition or by a digital printing technique.

15. The method according to claim 13, comprising depositing, with the help of an industrial robot, a seal on a face of the interior glass sheet opposite a face bearing the layer of the second enamel.

16. The laminated glazing according to claim 1, wherein the vehicle is a motor vehicle.

17. The laminated glazing according to claim 6, wherein the layer of second enamel coats between 0.1% and 3% of the third face of the interior glass sheet.

Description

EXAMPLES

[0073] The following examples, as well as FIGS. 1 to 5 below, illustrate the invention in a non-limiting manner.

[0074] FIG. 1 and FIG. 5 show a cross-section of a portion of a glazing according to the invention.

[0075] FIG. 2 shows the marking deposited on face 3.

[0076] FIG. 3 shows the marking deposited on face 3 and the outline of the enamel layer deposited on face 2.

[0077] FIG. 4 shows 3-point bending strength results.

[0078] FIG. 1 shows a cross-section of a portion of a glazing 1 according to the invention, more particularly a windshield, near an edge, so that the curvature of the glazing is not shown. The thicknesses of the glazing components are deliberately not shown to scale, in order to make them visible. As shown in FIG. 1, the exterior glass sheet 2 is adhesively bonded to the interior glass sheet 4 by means of a lamination interlayer 6, typically made of PVB (polyvinyl butyral). The face 2, denoted F2 on the figure, carries at the periphery of the glass a layer of enamel 22 forming a black opaque band. The face 3 of the glass, F3, carries a marking 42 in the form of a layer of enamel, here of white enamel and forming two parallel lines, typically of the order of 0.5 mm in width, opposite the enamel layer 22. Seen from the inside, the marking 42 is perfectly visible on the black background formed by the enamel 22, through the interior glass sheet 4, before a seal is applied.

[0079] FIG. 5 also shows, in a schematic way, a polymeric seal 7 placed on the face F4, and concealing the marking 42. The marking is thus no longer visible, neither from inside the vehicle, due to the seal 7, nor from outside the vehicle, due to the enamel 22.

[0080] FIG. 2 shows a particular example of a marking 42, in the form of a set of lines, forming a reference point for the subsequent deposition of the adhesive seal. Two parallel lines are deposited on the periphery of the interior glass sheet 4, plus a few additional lines in the lower part of the glass (in this case a windshield). The marking is formed by silk-screening a layer of white enamel. Each line in this example is 0.5 mm wide.

[0081] FIG. 3 shows the marking 42 of FIG. 2 and an enamel layer 22 superimposed. For the latter, only the outer contour of the enamel is shown, the enamel being deposited from the edge of the exterior glass sheet to the contour shown. FIG. 3 thus shows that the enamel 22 is capable of concealing the marking 42 in the final windshield.

[0082] Windshields were fabricated with the enamel designs shown in FIG. 3.

[0083] The exterior glass sheet, 2.6 mm thick, was made of green glass comprising as coloring species about 0.9% by weight of iron oxide. The interior glass sheet, 2.1 mm thick, was made of clear glass (0.1 wt % iron oxide) coated on the side intended to become face 3 with a stack of thin solar control layers comprising silver layers as functional layers.

[0084] The enamel band 22 was deposited on one side of the exterior glass sheet by screen-printing a black enamel composition (Ferro 14331) comprising a bismuth borosilicate glass frit. The wet enamel thickness was 15 μm.

[0085] In the comparative examples, the marking on face 3 was achieved by screen-printing a silver paste (SP1998C), comprising silver particles and a glass frit.

[0086] In the examples according to the invention, the marking was made by screen-printing a white enamel composition (PMI DV778380) comprising a bismuth borosilicate glass frit and white pigments. The wet enamel thickness was 18 μm.

[0087] After pre-firing (at 580° C.) the glass sheets were bent together (at 600° C.).

[0088] The assembly was then laminated with a 0.76 mm-thick PVB interlayer.

[0089] In the case of the silver paste marking, a transfer of silver from face 3 to face 2 during the bending process was observed, creating aesthetic defects visible from face 1, thus as a mechanical embrittlement, as shown by the mechanical tests below. On the other hand, in the case of the examples according to the invention, no aesthetic defect is observed, and in particular no white mark is visible from the face 1.

[0090] Mechanical tests in 3-point bending were also carried out.

[0091] FIG. 4 is a graph representing the probability of rupture (denoted P and expressed in %) as a function of the force (denoted F and expressed in Newtons) for the two comparative tests (C1, C2) where the marking was based on silver paste, and for two tests according to the invention (denoted 1 and 2).

[0092] It is clear from this figure that the choice of a marking according to the invention improves the mechanical strength of the windshield very significantly.