LAMINATED GLAZING COMPRISING A PERIPHERAL STEPPED ELEMENT MADE OF POLYMER MATERIAL HAVING A REQUIRED MAXIMUM PERMEABILITY TO WATER VAPOR

Abstract

laminated glazing includes a first glass sheet constituting an external face of the glazing, connected to a second glass sheet by a first interlayer adhesive layer, the edge of the first glass sheet being set back with respect to that of the second, a peripheral part of the free surface of the first glass sheet, its edge face, that of the first interlayer adhesive layer and a part of the surface of the second glass sheet extending beyond the first describing a continuous stepped contour which is covered, with interposition of adhesive, with a stepped element made of polymer material which can contain reinforcing fillers, which exhibits a permeability to water vapor at most equal to 5 g/m.sup.2/day.

Claims

1. A laminated glazing comprising at least a first glass sheet constituting an external face of the laminated glazing, connected to a second glass sheet by a first interlayer adhesive layer, in which an edge of the first glass sheet is set back with respect to an edge of the second glass sheet, a peripheral part of a free surface of the first glass sheet, an edge face of the first glass sheet, an edge face of the first interlayer adhesive layer and a part of a surface of the second glass sheet extending beyond the first glass sheet describing a continuous stepped contour which is covered with a stepped element with interposition of an adhesive, wherein the stepped element is made of polymer material which optionally contains reinforcing fillers and exhibits a permeability to water vapor at most equal to 5 g/m.sup.2/day.

2. The laminated glazing as claimed in claim 1, wherein the stepped element exhibits a permeability to water vapor at most equal to 1 g/m.sup.2/day.

3. The laminated glazing as claimed in claim 1, wherein the stepped element exhibits an elastic modulus at most equal to 5 GPa.

4. The laminated glazing as claimed in claim 1, wherein said polymer material is chosen from polyolefins (including polyethylene (PE), polypropylene (PP) or polyisobutylene (P-IB)), polyvinyl chloride and its derivatives, styrene polymer, polyacrylic (including polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA)), polyester (including poly(ethylene terephthalate)(PET) and poly(butylene terephthalate) (PBT)), polyoxymethylene (POM), polyamide (PA), fluorinated polymer, polycarbonate (PC), aromatic polysulfone, including polysulfone (PSU), polyphenylene ether (PPE), polyurethane and polyurea (PU), epoxy (EP), alone or as a mixture and/or copolymer of several of them.

5. The laminated glazing as claimed in claim 1, wherein the stepped element is composed of several lay ers of identical or different polymer materials.

6. The laminated glazing as claimed in claim 1, wherein said polymer material contains short-fiber and/or oriented lamellar reinforcing fillers.

7. The laminated glazing as claimed in claim 1, wherein the stepped element has a thickness at most equal to 800 μm.

8. The laminated glazing as claimed in claim 1, wherein said polymer material exhibits at least one surface treatment providing: a better barrier to water vapor performance: dense oxide deposited by chemical vapor deposition CVD, such as SiO.sub.2 or Al.sub.2O.sub.3; and/or an adhesion property.

9. The laminated glazing as claimed in claim 1, wherein the adhesive has a thickness at most equal to 350 μm.

10. The laminated glazing as claimed in claim 1, wherein the stepped element is covered with an air- and watertight seal which protects against solar radiation and fluids.

11. The laminated glazing as claimed in claim 1, wherein the stepped element is covered with a bead which provides the laminated glazing with aerodynamic continuity between glazing and a mounting structure and inertia to treatment fluids.

12. The laminated glazing as claimed in claim 1, further comprising at least a third glass sheet connected to the second glass sheet by a second interlayer adhesive layer.

13. The laminated glazing as claimed in claim 1, wherein the first glass sheet is made of inorganic glass with a thickness of between 0.5 and 5 mm or of polymer material with a thickness of between 0.5 and 5 mm.

14. The laminated glazing as claimed in claim 1, wherein the second glass sheet and, if appropriate, the third glass sheet are made of inorganic glass with a thickness of between 4 and 10 mm or of polymer material with a thickness of between 5 and 30 mm.

15. The laminated glazing as claimed in claim 1, wherein the interlayer adhesive layers are made of polyurethane (PU), polyvinyl butyral (PVB), ethylene/vinyl acetate (EVA), wherein a thickness of the first interlayer adhesive layer is of between 3 and 10 mm, and wherein a thickness of the second interlayer adhesive layer and, if appropriate, of the following layers is of between 0.5 and 4 mm.

16. A process for the manufacture of a laminated glazing as claimed in claim 1, comprising manufacturing the stepped element separately from its mounting structure by thermoforming, injection, injection molding and RIM (reaction injection molding) reaction, extrusion or coextrusion, blowing or compression/transfer.

17. A method comprising manufacturing a building glazing or a land, air or water vehicle glazing, or a street furniture with the laminated glazing as claimed in claim 1.

18. The method as claimed in claim 17, wherein the laminated glazing is an aircraft cockpit glazing.

19. The laminated glazing as claimed in claim 7, wherein the stepped element has a thickness at most equal to 300 μm.

20. The laminated glazing as claimed in claim 9, wherein the adhesive has a thickness at most equal to 200 μm.

Description

[0055] A better understanding of the invention will be obtained in the light of the following examples, with reference to the appended drawings, in which:

[0056] FIG. 1 diagrammatically represents, in section, a first embodiment of the laminated glazing of the invention;

[0057] FIG. 2 diagrammatically represents, in section, a second embodiment of the laminated glazing of the invention;

[0058] FIG. 3 is a partial diagrammatic view of a laminated glazing according to the invention in support of the specific explanations relating to the permeability to water vapor of the stepped element (“zed”) made of polymer material.

[0059] In these examples, a glass sheet denotes a chemically tempered aluminosilicate glass sheet, sold by Saint-Gobain Sully under the Solidion® registered brand name.

[0060] With reference to FIGS. 1 and 2, a laminated glazing comprises a first glass sheet 1 constituting an exterior face of the glazing, having a thickness of 3 mm, adhesively bonded to a second glass sheet 3 having a thickness of 8 mm by a first interlayer adhesive layer 2 of polyvinyl butyral (PVB) with a thickness of 5.3 mm.

[0061] A third glass sheet 5 with a thickness of 8 mm is adhesively bonded to the second 3 by a second interlayer adhesive layer 4 of polyvinyl butyral (PVB) with a thickness of 2 mm.

[0062] The edge of the first glass sheet 1 is set back with respect to that of the second 3, a peripheral part of the free surface of the first glass sheet 1, the edge face of the latter 1, the edge face of the first interlayer adhesive layer 2 and a part of the surface of the second glass sheet 3 extending beyond the first glass sheet 1 describing a continuous stepped contour which is covered with a stepped element 7 made of polyethylene terephthalate (PET) with a thickness of 355 μm.

[0063] Said continuous stepped contour is covered with the stepped element 7 with the interposition of a thickness of 100 μm of adhesive 6 made of polysulfide.

[0064] In FIG. 2, the stepped element 7 is covered with an air- and watertight seal 8, made of silicone, and with a bead 9 made of polysulfide which gives the laminated glazing an aerodynamic continuity between glazing and mounting structure, such as aircraft structure, and good inertia to the treatment fluids, as already explained.

[0065] With reference to FIGS. 1 and 2, the stepped element 7 can be more extended than represented, so as to cover, for example, the entire peripheral edge of the laminated glazing, in particular also the edge faces of the second glass sheet 3, of the second interlayer adhesive layer 4 and of the third glass sheet 5.

[0066] With reference to FIG. 3, relative to the stepped element 7 made of PET adhesively bonded to the edge face of the laminated glazing, three moisture (water vapor) flows are to be considered: [0067] flow making its way through the adhesive between the stepped element 7 and the first glass sheet 1, with a thickness h1; [0068] flow making its way through the adhesive between the stepped element 7 and the second glass sheet 3, with a thickness h2; [0069] flow making its way through the stepped element 7 with a thickness t.sub.zed.

[0070] These three flows diffuse into the first interlayer adhesive layer with a thickness H.

[0071] It is then possible to introduce the notion of equivalent barrier corresponding to an imaginary material precisely covering the interlayer thickness on the periphery of the glazing. The properties of permeation to water vapor of the equivalent barrier are then defined by:

[00001]$\begin{array}{cc}{p}_{eq}.Math.H=P_1\frac{h_1}{L_1}+P_2\frac{h_2}{L_2}+P_{zed}\frac{H}{t_{zed}}{p}_{eq}=\frac{P_1}{H}\frac{h_1}{L_1}+\frac{P_2}{H}\frac{h_2}{L_2}+\frac{P_{zed}}{t_{zed}}{p}_{eq}=p_1+p_2+p_{\mathrm{zed}}& \left[\mathrm{Math}1\right]\end{array}$

[0072] The values necessary for the calculation of p.sub.eq, and the result, are recorded in the following tables, for four laminated glazing structures specified under each of the tables.

TABLE-US-00001 TABLE 1 °¤ 1¤ 2¤ zed¤ total¤ t•or•L•[mm]¤ 11¤ 18¤ 0.5¤  °¤ h•[mm]¤  1¤   0.5¤ °¤ °¤ P•[g/m.sup.2/day .Math. mm]¤ 50¤ 50¤ 0¤   °¤ p•[g/m.sup.2/day]¤    0.67¤    0.20¤ 0.00¤ 0.87¤ •Case•of•an•AIRBUS•A320•(H = 6.8 mm)•with•metal•Zed¶

TABLE-US-00002 TABLE 2 °¤ 1¤ 2¤ zed¤ total¤ t•or•L•[mm]¤ 11¤ 18¤ 0.355¤ °¤ h•[mm]¤   0.1¤   0.1¤ °¤ °¤ P•[g/m.sup.2/day .Math. mm]¤ 50¤ 50¤ 0.2¤  °¤ p•[g/m.sup.2/day]¤    0.07¤    0.04¤ 0.56¤  0.67¤ •Case•of•an•AIRBUS•A320•(H = 6.8 mm)•with•Zed•made•of•PET¶

TABLE-US-00003 TABLE 3 °¤ 1¤ 2¤ zed¤ total¤ t•or•L•[mm]¤ 12.2¤ 17.8¤ 0.5¤  °¤ h•[mm]¤ 1¤   0.5¤ °¤ °¤ P•[g/m.sup.2/day .Math. mm]¤ 40¤   40¤   0¤   °¤ p•[g/m.sup.2/day]¤  0.68¤  0.23¤ 0.00¤ 0.91¤ •Case•of•an•AIRBUS•A350•(H = 4.8 mm)•with•metal•Zed¶

TABLE-US-00004 TABLE 4 °¤ 1¤ 2¤ zed¤ total¤ t•or•L•[mm]¤ 12.2¤ 17.8¤ 0.355¤ °¤ h•[mm]¤  0.1¤  0.1¤ °¤ °¤ P•[g/m.sup.2/day .Math. mm]¤ 40¤   40¤   0.2¤  °¤ p•[g/m.sup.2/day]¤  0.07¤  0.05¤ 0.56¤  0.68¤ •Case•of•an•AIRBUS•A350•(H = 4.8 mm)•with•Zed•made•of•PET¶

[0073] As is shown by the comparison of tables 1 and 2, on the one hand, and 3 and 4, on the other hand, the replacement of a stepped metal element 7 by a stepped element 7 made of PET is capable of giving a permeability p lowered from 0.87 to 0.67 g/m.sup.2/day, on the one hand, and from 0.91 to 0.68 g/m.sup.2/day, on the other hand.

[0074] This is because the deformable polymer material more easily matches the shape of the glazing without mounting constraints. Its use makes it possible to reduce the thicknesses of adhesive from 500 μm or 1 mm to 100 μm, hence the possibility of reducing the value of the permeability p with respect to the metal zed (stepped element) 7.

[0075] The nonmetal zed eliminates all the disadvantages related to the electrical conductivity of metals, as expected.

[0076] The manufacturing costs are lower for the polymer material, in particular by thermoforming, than for metals, especially as regards the tooling equipment.