EP0673351A1

EP0673351A1 - Improved glazing

Info

Publication number: EP0673351A1
Application number: EP94919720A
Authority: EP
Inventors: Jean Cheron; Pierre Chaussarde
Original assignee: Saint Gobain Vitrage SA; Saint Gobain Vitrage International SA
Current assignee: Saint Gobain Glass France SAS; Saint Gobain Vitrage SA
Priority date: 1993-06-22
Filing date: 1994-06-16
Publication date: 1995-09-27
Also published as: CN1111056A; JPH08500553A; FR2706884A1; WO1995000451A1; US5585188A; CA2142984C; CA2142984A1; FR2706884B1; CN1102541C; JP4122051B2

Abstract

Glazing including at least one glass sheet (8, 9) with a protective tape (11, 12) at least partially covering its edge.

Description

GLAZING WITH IMPROVED PROPERTIES

The present invention relates to glazing, in particular glazing used in the aeronautical field.

The glazing can be monolithic or laminated, made of glass or plastic. It can also be a composite glazing consisting of an assembly of rigid sheets, glass and / or plastic and flexible sheets.

A composite glazing used in the aeronautical field usually consists of at least two sheets of thermally or chemically toughened glass between which there is a plastic interlayer which can possibly be made up of several plies or sheets.

When the glazing is placed in the usual conditions of a flight at high altitude, it is subjected, on the one hand, to significant pressure differences between these two faces and, on the other hand, to equally significant temperature differences between the middle part and the peripheral part of the glazing. In addition, it also undergoes vibrational stresses. As an indication, the pressure difference can reach 900 millibars and the temperature difference can reach around 70 ° C. To these already very high constraints, there are added constraints due, for example, to a shock during the flight, in particular at low temperature, such as the impact of a bird, or other local constraints.

Given these particularly severe stresses, such glazing deteriorates during use in a more or less long time. Solutions have already been proposed to reduce the risk of glazing failure. One of the most frequent causes of failure is the difference in coefficient of thermal expansion between the glass and the plastic interlayer which is, generally, made of polyvinyl butyral. One solution is to introduce a material with a low coefficient of thermal expansion in the marginal part of the glazing, between the interlayer and the glass. Another solution consists in placing a continuous film of a material of a different nature with a lower modulus of elasticity between the interlayer and the glass. These solutions can, however, lead to optical defects in the glazing. EP 508 864 has also proposed a polyvinyl butyral interlayer made up of several plies, the plasticizer content of the plies in contact with at least one glass sheet being higher than in the interior plies. This characteristic also makes it possible to reduce or even eliminate the known stresses leading to cleavage of the glass, that is to say to a rupture in a plane substantially parallel to that of the glass, in particular when it is chemically toughened. .

These glazings of previous documents have, on the whole, presented improved properties. They have satisfactory lifetimes. However, in certain cases, important precautions during the manufacture of the glazing are necessary. The present invention overcomes these drawbacks.

The present invention relates to a glazing unit having the qualities of longevity sought in the temperature and pressure conditions to which a glazing unit used in the aeronautical field may be subjected.

The inventors obtained this result by highlighting the constraints to which the glazing is subjected during its manufacture and its mounting in the body of the aircraft. The inventors have shown that in particular during handling, the glazing could be subjected to shocks creating micro-defects which, although not being visible, could deteriorate the glazing. The inventors have also determined the characteristics to remedy these defects and have found a solution compatible with the requirements of the aeronautical field and having the advantage of being, moreover, easy to implement. The invention relates to a glazing whose edge is, at least partially, covered by a ribbon.

In one of its aspects, the invention relates to a glazing unit comprising at least one sheet of glass whose edge is, at least partially, covered with a protective tape. The material constituting the tape according to the invention is chosen from the following materials: silicone, rubber, thermosetting or thermoplastic elastomers. The material must be compatible in particular with the plastic spacers used as well as with the seals which are generally mounted on the periphery of the glazing. These are seals and / or mounting and / or dismantling for example. These joints can be extruded or encapsulated. They are usually made of silicone. Furthermore, the material used according to the invention is preferably light, that is to say with a density advantageously less than 1.2 g / cm ³ .

The tape of the invention is preferably made of polyurethane. The hardness of the tape is preferably greater than that of the joint in order to obtain good assembly. It is preferably less than 90 Shore A and is, for example, between 60 and 90 Shore A. It is moreover preferable that the tape has good tear resistance. It is preferably greater than 2 kg measured according to standard ASTM 1 938 and can even reach a value of the order of 2.5 kg.

Preferably, the ribbon is left on the glazing which is mounted in the cockpit or the cabin of the aircraft. As we have seen previously, the glazing then undergoes significant thermal stresses. For these reasons, the ribbon has a thermal dimensional stability after 30 min at 120 ° C. of less than 1%. Furthermore, according to an advantageous variant of the invention, the ribbon covers, at least partially, the edge of at least one sheet of glass and, preferably, of each of the sheets of glass taken individually entering into the constitution of the glazing. The ribbon is preferably applied to the glass sheet before the glazing production cycle. The glass sheet is then protected by the tape from any stress from the beginning to the end of the stages of manufacturing and mounting the glazing. The ribbon must then have a thermal dimensional stability such that it supports the cooking conditions of the assembly which can reach more than 100 ° C. under a pressure of 10 bars or more.

The total thickness of the tape is preferably between 0.1 and 2 mm. The greater the thickness, the more the tape according to the invention has improved properties, in particular energy absorbing properties. However, preferably, this thickness does not exceed 2 mm for reasons of space. It is obvious that each component of the glazing has precise dimensions and that the dimensions of the entire glazing must correspond exactly to the location provided, in the body of the aircraft, for example. In addition, the edges of the glazing have a relatively large size due, in particular, to the presence of different functional elements such as connection elements, guide ... and the presence of seal (s). Because of this little space available, the tape according to the invention advantageously comprises an adhesive layer which allows, by the simple application of pressure, to securely fix the tape to the glazing. The pressure can be exerted, for example, by the application of a grooved roller, a spatula or any other means. The adhesive layer is preferably of the acrylic type; it has a thickness of the order of 0.01 to 0.2 mm. It is preferably of the order of 0.05 mm. The tape is advantageously unrolled using a reel and is immediately afterwards applied against the edge of the glazing and, possibly, may overflow on the faces of the glazing. The ribbon is thus applied uniformly in a simple and practical manner, despite the thinness of a glass sheet the thickness of which can be as small as 3 mm and despite the shape of the edge which can be, for example, round. The coated glass sheet according to the invention is advantageously a chemically toughened glass sheet, that is to say reinforced by a chemical treatment known per se. This treatment consists, for example, of an ion exchange in the surface layers of the glass, the small ions being replaced by larger ions. This ion exchange creates a superficial zone in compression. The resistance of this surface area in compression is particularly important. However, its thickness is less important than a thermally toughened glass sheet. The present invention reduces the risk of deterioration of the glass surface during improper handling.

Other characteristics and advantages of the invention will appear in the following description given with reference to an exemplary embodiment and to the figures in which:

FIG. 1 comprises different diagrams 1 a to 1 f representing different possible positions of the tape according to the invention,

FIG. 2 represents, in section, an embodiment of a glazing according to the invention,

- Figure 3 shows, in section, a variant of a glazing according to the invention, - Figure 4 shows, in section, another variant of a glazing according to the invention,

FIG. 5 represents, in section, another variant of a glazing according to the invention,

- Figure 6 shows, in section, another variant of a glazing according to the invention.

Figure 1 shows a monolithic glazing 1 consisting of a sheet 2. This sheet is, for example, glass. Its edge 3, the vertices of which are referenced in 5 and 6, is covered with a ribbon 4 according to the invention. On diagrams 1 a to 1 c, edge 3 is rounded while it is straight on diagrams 1 d to 1 f. As illustrated in diagrams 1 a and 1 d, the ribbon can overlap on the faces of the sheet 2. It can also overlap only on one side. It may also not overflow while protecting, for example, the apex 5 or the apex 6, as illustrated in the diagrams 1 b and 1 e. It may also not cover that part of the edge of the glazing, as illustrated in diagrams 1 c and 1 f, while protecting or not protecting the apex 5 and / or the apex 6.

Only a few provisions are illustrated in these diagrams. Of course, other arrangements are possible without departing from the spirit of the invention.

The glazing according to the invention has improved properties, in particular, improved impact resistance. The results of the tests carried out on the glazing shown in diagram 1 a are the following:

The glass sheet is chemically toughened. If a steel ball is dropped on the rounded top of the glass sheet simulating shocks during handling, we observe defects when the ball has an energy greater than or equal to 0.1 Joule. If the same test is carried out on the glazing shown in diagram 1 a, fitted with a silicone-type ribbon, defects are observed for an energy of 0.5, 1 or 2 Joules depending on the thickness of the ribbon in silicone which is 1, 2 or 3 mm respectively.

If the tape is composed of a polyurethane whose Shore A hardness is 80, the thickness of 0.41 mm and the tear resistance of the order of 2.6 kg according to the test referenced ASTM 1,938, the faults appear for an energy greater than or equal to 9 Joules. Furthermore, the ribbon is securely attached to the glass sheet. It is fixed to it by an adhesive layer of the acrylic type with a thickness of 0.04 mm. The adhesion values measured with a polyurethane tape described above are of the order of 1 N / mm.

These values are measured according to the so-called 180 ° peel test, described in standard ASTM-D-100. The test pieces tested are left at room temperature for 24 hours. The traction speed here is 305 mm / min.

As an indication, the drop test of a steel ball 50 mm in diameter and a mass of 500 g is carried out on a flat test tube covered with a polyurethane tape according to the invention as described below. above. This test simulates shocks that the glazing can undergo during handling. The glass breaks for an energy greater than or equal to 10 Joules while, for the same sheet of bare glass, that is to say without ribbon, the limit energy is 3 Joules. This example illustrates the improved properties glazing according to the invention as well as the fragility of the edges of the glazing which can cause the glazing to break.

As illustrated in FIG. 2, advantageously, a seal 7 is mounted on the periphery of the glazing. This seal is preferably a seal and / or assembly-disassembly. It is extruded or encapsulated. The glazing 1 then comprises a somewhat composite seal made up of the tape 4 according to the invention, arranged according to diagram 1a in FIG. 1, and of the seal 7. The tape can also be arranged differently. It is then ready to be mounted in a body bay or in the frame of a window or door, or in the cockpit or cabin of an airplane.

The seal is, in this example, made of silicone with a thickness of 2 mm, produced by encapsulation. The tape is, in this example, made of polyurethane like that described in relation to FIG. 1. Defects appear when the energy of a steel cylinder falling on the rounded top of the glazing covered with both tape 4 and seal 7, is greater than or equal to 20 Joules.

The glass sheets shown in FIGS. 1 or 2 can also be used in the construction of laminated glazing as shown, for example, in FIGS. 3 and 5.

Figure 3 shows a laminated glazing consisting of two sheets of glass 8 and 9 between which there is an interlayer of flexible plastic 1 0. This interlayer, shown schematically, may include several folds or sheets, possibly made of different materials. In the figure two ribbons, 1 1 and 1 2, respectively surround the edges of the sheets 8 and 9. In this figure, the ribbon 1 1 is shown projecting on the faces 1 3 and 14 of the sheet 9, while the ribbon 12 does not overflow. The figure thus illustrates the different possible positions of the ribbons relative to the sheets and the different possible overlaps of sheets, rigid or flexible, without departing from the spirit of the invention. A seal, not shown, can also coat the entire edge of the glazing thus formed. Figure 4 illustrates another variant of the invention in which the tape 1 5 according to the invention covers all of the laminated glazing. It is then applied after assembly and does not require, for example, power withstand the temperature and pressure conditions required for such an assembly.

This glazing can be used for transport vehicles, for the building ... FIGS. 5 and 6 illustrate glazing for aircraft according to a preferred variant of the invention. They consist of three glass sheets 1 6, 1 7 and

1 8. The glass sheets 1 6 and 1 7, in particular the sheet 1 6, are exposed to the pressure and to the temperature prevailing inside the aircraft. The sheet 1 8 is exposed to external conditions. A heating network 1 9 is usually provided near the sheet 1 8 in order to remove the frost and / or the mist from the glazing. It consists of electric heating wires, not shown, electrically connected to collecting strips themselves connected, via a connection element, to a source of electric power. Conductive wires to eliminate static charges can also be provided.

Plastic spacers 20 and 21 are provided between these glass sheets. It is usually one or more polyvinyl butyral sheets, possibly consisting of several plies. In the embodiment shown, the sheets 1 6 and 17 as well as the interlayer 20 are larger than the sheet 1 8 and the interlayer 21. The interlayer 21 can also be of the same dimension as the sheet 1 7, for example. The insert 20 is generally reinforced by a peripheral belt, or insert, represented at 22, embedded in the insert. This belt may optionally include holes for bolted mounting of the glazing to the structure of the aircraft. This belt can be made of a stainless metal, aluminum or based on a fibrous structure. Its thickness is around 2 mm.

The ribbons 23, 24 according to the invention can cover the edge of the sheets 1 6 and 1 7 as shown in FIG. 5. The ribbons 23 and 24 cover, at least partially, the edge of the sheets 1 6 and 1 7, respectively, taken individually. Of course these sheets are covered before their assembly, preferably just after their manufacture. The ribbons can also cover the entire glazing as shown in 25 in FIG. 6. The ribbons 23, 24 and 25 may or may not overflow on the faces of the glass sheets, completely or partially covering the edges of the sheets or of the glazing.

Figure 5 illustrates an advantageous variant where the sheets 1 6 and 1 7 are made of chemically toughened glass and also have a rounded shape. The sheet 1 8 can also be covered with a ribbon according to the invention.

The method of manufacturing a glazing unit according to the invention, in particular a laminated glazing unit, comprises the following steps.

A tape according to the invention is applied to the edge of a glass sheet which has just undergone a chemical toughening treatment. The tape comprising an adhesive layer is unwound from a reel and applied against the edge, possibly overflowing on one or the faces of the glass sheet. Advantageously, the application is carried out by means of a grooved roller in order to make the application very uniform. The ribbon thus protects the glass sheet from the start of the glazing production cycle. A protective packaging film possibly envelops the entire glass sheet. This glass sheet can be stored. It is then assembled with other glass sheets, possibly also provided with ribbon (s) according to the invention. The packaging film is, if necessary, obviously removed before assembly.

Advantageously, several plies or sheets of flexible plastic material are disposed between these glass sheets as well as a heating network, antistatic, a reinforcement belt ... This assembly is preassembled by a calendering technique or by introducing the assembly into a pocket subjected to a temperature and evacuated. The preassembly is then introduced into an autoclave where it undergoes a temperature of the order of 1,00 ° C. at 10 bar of pressure. At the exit of the autoclave, the assembly is integral, that is to say that both the different plies constituting an interlayer that the interlayer and the glass sheets are intimately linked. A silicone seal is then molded onto the periphery of the glazing. A wrapping film can optionally protect each side of the glazing. The latter is then mounted in the body of the aircraft by bolting or by means of a support mechanical, for example by pinching. The packaging film is then removed if necessary.

The invention relates to monolithic or laminated glazing, optionally provided with a seal or any other element of glass or plastic without departing from the spirit of the invention.

Although the invention has only been described in relation to glazing used in the aeronautical field, it can also be used for transport vehicles or for the building industry.

Claims

I. Monolithic or laminated glazing in glass and / or plastic, characterized in that its edge is, at least partially, covered by a ribbon.

2. Glazing according to claim 1, characterized in that the strip is made of a material whose hardness is less than 90 Shore A.

3. Glazing according to claim 2, characterized in that the strip is made of polyurethane.

4. Glazing according to claim 1, characterized in that the thickness of the strip is between 0, 1 and 2 mm.

5. Glazing according to claim 4, characterized in that the tape comprises an adhesive layer.

6. Glazing according to claim 5, characterized in that the adhesive layer is of the acrylic type.

7. Glazing according to one of the preceding claims, characterized in that the glass is chemically toughened.

8. Glazing according to claim 1, characterized in that the edge of the glazing is rounded.

9. Glazing according to one of the preceding claims, characterized in that a seal is mounted on the periphery of the glazing provided with the tape according to the invention.

10. Glazing according to one of the preceding claims, characterized in that the glazing is laminated.

I I. Glazing according to claim 10, characterized in that the edge of at least one of the sheets of the glazing is covered, at least partially, by the tape according to the invention.

1 2. Glazing according to claim 1 1, characterized in that the edge of at least one sheet of glass, taken individually, is covered at least partially with a tape according to the invention, before assembly.