GB2228519A

GB2228519A - Glazing panels

Info

Publication number: GB2228519A
Application number: GB9002088A
Authority: GB
Inventors: Michel Laurent; Calogero Chinzi
Original assignee: Glaverbel Belgium SA
Current assignee: AGC Glass Europe SA
Priority date: 1989-02-02
Filing date: 1990-01-30
Publication date: 1990-08-29
Anticipated expiration: 2010-01-30
Also published as: NL193954C; SE9000359D0; GB9002088D0; NL193954B; IT9067059A1; FR2642418A1; NL9000246A; SE9000359L; IT9067059A0; DE4002514C2; FR2642418B1; DE4002514A1; GB2228519B; SE507710C2; BE1003582A5; IT1239863B; ES2021964A6

Description

9 GLAZING PANELS The present invention relates to multiple glazing panels

for motor vehicles, that is to say panels comprising two or more panes of glass. In particular it is concerned with the means whereby the individual panes forming the panel are securely joined together.

Multiple glazing panels in motor vehicles provide thermal and sound insulation which significantly improves the comfort of the vehicle passengers. The panels are mainly used as side windows, fixed or movable, but they can also be used as rear windows, heated or not, as sunshine roof panels or even as windscreens.

Like the multiple glazing used in buildings, vehicle multiple glazing panels are formed of parallel panes of glass and a peripheral spacing strip between adjacent panes which serves to enclose an insulating space between them. In contrast to panels used in buildings, those fitted to vehicles are subjected to mechanical stresses of much greater variety and severity. The stresses result for example from jarring caused by the state of the road, from vibration within the vehicle and from variations in temperature and altitude. In the case of door-mounted panels, especially side windows, they are also subjected to repeated severe shock when the door is slammed. Moreover if the panel is slidable into a door recess the grooves in which it slides impose shearing forces upon the constituent panes. Such shearing forces can be particularly 2 severe at the upper edge of a door-mounted sliding window when it is - moved upwards into the upper groove in the door frame. All of these stresses tend to separate the constituent panes from the spacing strip, thereby leading initially to breakage of the seal around the insulating space and in the extreme to break-up of the panel.

various prior proposals have been made for combinations of structural elements to form a suitable joining means for the panes forming vehicle multiple glazing. French patent specification 2 609 946 Al discloses a vehicle double glazing panel in which a peripheral spacer constituted by an adhesive forms the joint between the panes. German laid-open patent specification 37 12 105 A1 describes a particular combination of a hollow section, at least part of which includes a desiccant chamber, associated with an adhesive strip between the panes. However no prior proposal has been found to give a fully satisfactory solution to the problem.

We have now discovered a sealing joint, formed by a particular combination of two specific elements, which can cope with the difficulties discussed above and thus solve the problem.

Accordingly the present invention provides a multiple glazing panel for a vehicle, which panel comprises at least two panes of glass and a sealing spacer between the or each pair of adjacent panes so as to retain the panes in spaced relationship to each other, form a sealed space between them and extend around the periphery of the sealed space, characterised in that the or each sealing spacer comprises a first element in contact with both adjacent panes and with the sealed space, the said first element being formed of a flexible and malleable material and providing a barrier to entry of humidity into the sealed space, and a second element in contact with both adjacent panes and being at least partially formed of an adhesive having a modulus of elasticity greater than 1.4MPa (measured as hereinafter defined).

3 The invention also provides a method of manufacturing a multiple glazing panel for a vehicle window, which comprises inserting a sealing spacer between two adjacent panes of glass so as to locate the panes in spaced relationship to each other, wherein a first element of the sealing spacer, which element is formed of a flexible and malleable material, is placed on one face of one of the panes to form a continuous elongated strip extending around the margin of the face and close to its edge, the other pane is then placed on the first element and the panes are pressed together until the interspace between them is reduced to a desired distance and to form a sealed space between the panes, and a second element, which is at least partially formed of an adhesive having a modulus of elasticity greater than 1AMPa (measured as hereinafter defined), is then placed in contact with the panes around at least part of the first element so as to form a strong adhesive bond between the panes.

Multiple glazing panels according to the invention provide the advantage of robust construction which withstands the severe stresses imposed by use in a motor vehicle. The defined combination of structural elements ensures a strong sealing joint between the constituent glass panes and an effective barrier to the entry of humidity into the space between them. This is in marked contrast to previous seals, such as solder commonly used in double glazing panels for buildings, which tend to split apart when subjected to the forces imposed by vehicle door slamming.

The use of a flexible and malleable material as the first element of the sealing spacer also assists in ensuring a complete barrier to humidity and facilitates production of multiple glazing of a particular shape, for example curved in one or more planes, to satisfy complex vehicle contours. One suitable version of the first element is an elastomeric ribbon, for example a not fully polymerised n '4_ 4 polychloroprene-based elastomer, with an electrical heating wire running through its centre. With such a ribbon a current can be passed through the wire at the time of applying the ribbon so as to complete the polymerisation of the elastomer when the ribbon is in its required configuration on the glass.

The preferred material for the first element is butyl rubber, which is advantageous in having good adhesive properties and more particularly in having outstandingly high impermeability to water vapour. It can conveniently be applied by hot extrusion.

In one preferred embodiment of the invention the first element is in the form of a pre-formed butyl rubber ribbon with a thread running through it to form a central core. Suitable materials for the thread include aluminium, cotton or synthetic fibres. In constructing a panel the butyl rubber ribbon is gently pressed into place between the panes. The material of the ribbon preferably includes a silane, so as to improve adhesion to the glass. The ribbon also preferably incorporates a desiccant, for example a molecular sieve, thereby providing a further safeguard to ensure that the sealed space remains free of moisture. The quantity of desiccant must not however be so high that it harms the malleability or ductility of the ribbon. For example the butyl rubber can be doped with 10-20% of the desiccant. If desired a foil strip, for example of a metallic or plastic extrusion, can be inserted between the panes and adjacent to the butyl rubber. The metal for this purpose can be lead or aluminium. Such a strip is advantageously used in combination with hot extruded butyl rubber. It is beneficial in providing a further barrier to the passage of moisture.

In a further embodiment of the invention the first element includes a corrugated metallic strip, typically of aluminium, embedded in butyl rubber or having butyl rubber on one or more z,X._ of its faces. In this embodiment the aluminium strip provides some - resistance to crushing of the butyl rubber and thus assists in maintaining the required sealing and spacing between the glass panes.

In addition to or instead of the desiccant discussed above an insert containing a desiccant can be included in the sealed space. The insert can for example be a desiccant-filled container or a desiccant-bearing plastic strip. It is preferably located at a position in the space which is not normally visible to the occupants of the vehicle, and can if desired be secured to the first element.

It is also possible to include within the first element a microporous material, for example in the form of one or more pellets, which hinders the entry of water molecules into the sealed space but permits some passage of other gases. This embodiment is advantageous for panels which may be subjected to large variations in atmospheric air pressure or extremes of temperature.- The modulus of elasticity of the adhesive employed in the second element of the sealing spacer can be determined for the purposes of the invention on test-samples of the adhesive in the form of a film. It is determined herein at a film temperature of 200C and at 100% elongation, measured under traction.

The adhesive of the second element preferably has a modulus of elasticity greater than 1AMPa and preferably not greater than 4MPa. It is preferably of a type which neither releases volatile solvents, which could enter the interspace between the glass panes, nor presents a substantial loss of constituent material at temperatures below 1000C, thereby indicating that it is stable at temperatures up to 1000C. It preferably has a glass transition temperature Tg of below 6 -45C, thereby ensuring good stability at low temperatures. The glass transition temperature Tg was measured for the purposes of the invention by differential scanning calorimetry using a Perkin Elmer apparatus and the procedure described in IRS Physical Chemistry Series 2, 1975, Volume 10, published by Butterworths London.

The adhesive also preferably has a water permeability of less than 2.25g x mm of thickness per m 2 x 24h x kPa water 2 pressure, most preferably 1. 5g x mm of thickness per m X 24h x kPa water pressure. This ensures that the panel resists humidity without risk of separation of the panes.

Suitable materials for the adhesive include those based on silicone, polysulphide or polyurethane. Polyurethane adhesives are preferred, most preferably a two-component polyurethane, for example UCETHANE (manufactured by MB) or ISOSEAL 2000 (manufactured by TREMCO). These materials are impervious to water vapour, resistant to vibration and to vehicle-washing detergents, stable over a wide temperature range and have good resistance to ultra-violet radiation. ISOSEAL 2000 has an elastic modulus of about 1.7MPa, UCETHANE has an elastic modulus of more than 1. 8MPa. (ISOSEAL and UCETHANE are registered trade marks).

Once the adhesive is fully set the second element not only binds the two panes firmly together but also protects the first element against deformation and thus assists in retaining the panes in their required relative disposition.

The margins of glass panels intended for vehicles often carry a black or other-coloured silk screen printed lacquer to hide the margin and/or to improve the appearance and to conform to the shape of the vehicle. Such lacquers tend not to bind well to conventional adhesives. Thus if the lacquered portion is located on a face which is to receive the second element adhesive the use of the preferred polyurethane adhesive is most desirable to ensure a strong joint between the panes. It 7 is a particular advantage of the present invention that it provides a strong double glazing panel despite incorporating such a lacquered portion.

Extensive tests simulating conditions faced by vehicle glazing panels were conducted in respect of adhesives to be used in panels according to the invention. These included mechanical and climatic tests, specifically traction tests, exposure to high and low temperatures, immersion tests and tests according to German standard DIN 52344. It was found that the two component polyurethane having the qualities listed above performed particularly well in these tests.

As dictated by the shape of a vehicle panel frame into which it must fit, the glazing panel may be flat or curved in one or more planes. The constituent panes can be of tempered glass, for example treated thermally or chemically. Such treatments are advantageous in improving such qualities as the strength of the panel and the manner in which it may break. Chemically treated glass generally has increased strength for a given thickness and thus permits reduction of the thickness of the panes and thereby the weight of the panel. Tempered glass, even if it reaches the breaking point, tends to break into fairly small uniformly-sized fragments which tend to be less hazardous than the fragments produced on breaking non-tempered glass. The panes can be formed of clear glass or of glass which is resistant to heat radiation and which may or may not carry one or more anti-solar or low emissivity coatings. At least one of the panes can be formed of laminated glass, for example to improve impact resistance.

Although they will generally be required to have the same curvature as each other, the panes in a given panel need not be of the same dimensions. A particularly convenient range of options for a double glazing panel is provided by making the two panes of a similar outer shape but with one slightly smaller than the other. The alignment of the larger and 8 smaller panes can be arranged so that the panel incorporates a step-at the margin of one or more sides. Such stepped construction is often advantageous in fitting the panel into the respective opening in the vehicle body and is particularly advantageous for a sliding panel in a vehicle door. In the latter instance, the supporting grooves at the sides or top of the door frame need only accomodate the outer margins of the larger pane, not of the whole panel, thereby permitting the grooves to be of similar dimensions to those for single glazing panels and also, if only the larger pane is fitted into the grooves, avoiding imposition of shearing forces between the constituent panes when the window is opened or closed. In some instances it is preferred to locate the panel on the vehicle so that the larger pane occupies the external position relative to tM? smaller pane and thereby shields the sealing spacer fromthe atmospheric conditions. In other instances it is preferred to make the smaller panel occupy the external position so that the external shape of the panel more closely follows the lines of the vehicle body shell and thereby improves the vehicle's aerodynamic properties.

An additional edging strip, for example a metallic or plastic extrusion, can be attached to one or more of the edges of the panel. This can provide extra strength for the panel, for example by acting as the part of a panel that engages the retaining grooves, but is sometimes required merely for decorative purposes. The strips need not extend along the full length of the edges unless the particular intended usage demands this. An especially strong construction, best suited to a panel edge which does not have the stepped alignment of the panes, is provided by employing such a strip with a U-shaped construction. This permits the margin of the assembled panel to be received as a contact or adhesive fit within the U.

9 In one preferred embodiment such a strengthening strip is provided on the lower edge of the panel to reduce shearing forces on the sealing spacer during upward and downward movement of a side window, especially one in which the movement mechanism acts only on the lower edge.

The individual panes of glass in the panel are typically of a thickness of about 3mm each. The distance between them, i.e. the "thickness" of the sealed space, is preferably in the range 1 to 4mm, most preferably about 3mm. It can be filled with dry air, or special fillers including one or more gases such as argon, SF6 or krypton, or materials such as aerogel. Such special fillers improve the thermal and acoustic insulation of the panel.

The butyl rubber extrusion or ribbon discussed above typically has an initially circular cross section with a diameter of about 4mm prior to application. After the second pane has been pressed into its required position the ribbon cross section distorts to a flattened shape, adopting the 3mm thickness between the panes and extending to about 4.5mm in the plane of the panes.

A preferred assembly procedure for a panel according to the invention includes first washing and drying the glass panes. A butyl rubber ribbon is then applied to one of the panes, together with any other portions of, or associated with, the first element. If the panel includes panes of different sizes the smaller pane should be chosen. The butyl ribbon is normally applied at a warm ambient temperature, typically 3CC, but can alternatively be applied hot. It is preferably aligned by means of a roller with a guide which permits a constant distance, for example 4mm, to be maintained from the edge of the pane. Placement of the ribbon is effected around the whole periphery of the pane (with the 4mm inset as specified above) and the ends of the ribbon are joined togetherl at the point at which they meet.

The o ther pane is then positioned on the first element and a hollow needle is inserted through the butyl ribbon to permit the escape of air from the interspace during the subsequent pressing of the second pane on to the first pane.

Any additional strip to be located between the two elements of the sealing spacer is inserted at this stage. It can serve as a stop to ensure a defined minimum thickness for the sealed space created in the subsequent pressing.

The pressing can conveniently be effected by calendering. In one preferred procedure according to the invention the pressing is conducted with the assistance of a press having plates to which are attached inflatable bags. The bags apply the assembly pressure to the opposed faces of a double panel. This facilitates joining the component parts of double glazing with spherical curvature and the same press can be used without modification to join panels having different curvatures. Pressing is continued until the interspace has the required dimensions. The hollow needle is then withdrawn and the hole thereby created is filled with a butyl rubber plug.

The second element adhesive is then applied to fill the space defined by the margins of the inner faces of the panes and the surface of the butyl rubber strip, or of any intermediate strip inserted after the butyl rubber strip. If the panel includes panes of different sizes a masking strip is preferably placed around the margin of the inner face of the larger pane so as to avoid applying any of the adhesive to the said margin.

Any protective or decorative strip may now be added to the edges of the panel and can be secured in place by contact with the second element adhesive.

1 1 11 The preferred adhesives generally solidify within about 30 minutes and are completely polymerised within about 3 hours. Any marginal protective tape can then be removed.

The invention is illustrated below with reference to the figures, which show several different forms of double glazing according to the invention.

Figure 1 shows a complete double glazing panel suitable for use as a sliding window in a motor vehicle door.

Figures 2 and 3 show details of the Figure 1 panel. Figure 2 is a sectional view of part of the panel viewed from a position indicated by AA' on Figure 1. Figure 3 is a sectional view of part of the panel viewed from a position indicated by B-B, on Figure 1.

Figure 4 shows details of an alternative version of portions of the Figure 1 panel, viewed from a position equivalent to A-A' on Figure 1.

Figures 5, 6 and 7 show cross-sectional details of other types of panel. All are viewed from a position similar to A-A' on Figure 1.

For convenience in the following description the same reference numerals are used in references to different versions of panel for those components which are common to them.

The panel shown in Figures 1 to 3 includes an outer glass pane 10 and an inner glass pane 12 (the terms "outer" and "inner" being used to refer to the panes which when installed in a vehicle will form respectively the external and internal surfaces), the outer pane 10 being slightly larger than the 12 inner pane 12 and overlapping the inner pane 12 on all sides. Both panes 10 and 12 are 3mm thick and have been treated by thermal hardening and slightly curved.

Between the panes 10 and 12 a sealing spacer 14 extends around the whole peripheral margin of pane 12 so as to retain the panes 10 and 12 in secure spaced relationship approximately 3mm from each other. The spacer 14 also encloses a sealed insulating space, indicated generally by the number 16, between the two panes 10 and 12. Around their periphery the panes 10 and 12 carry, on the surfaces facing the sealed space 16, a band of silk screen printed black enamel (not illustrated). The size of the enamel bands on each of the panes 10 and 12 is such that they just mask all of the sealing spacer 14 from view.

The spacer 14 includes as a first element a butyl rubber ribbon 22 and as a second element a strip 26 of polyurethane adhesive. The ribbon 22 is formed of butyl rubber doped with 10 to 20% of desiccant, contains a silane to enhance adhesion to the glass and has a continuous core 24 of a polymeric thread with a diameter slightly less than lmm. The ribbon 22 is flexible and malleable and can easily follow the surface contours and corner shapes of the curved panes 10 and 12 forms a very effective barrier against humidity.

At the base of the insulating space 16, and attached to the sealing spacer 14, is a desiccant plaquette 18 formed of powdered zeolite molecular sieve (63% by weight) in epoxy resin (37% by weight). The plaquette 18 serves to maintain moisture-free conditions in the insulating space 16. Support members 20, of L-shaped cross section and fabricated in aluminium, are provided at the lower edge of the pane 12 and secured by polyurethane adhesive to the pane 10 so as to give the assembled panel additional strength.

Z_ 13 The adhesive for the strip 26 is a polyurethane such as UCETHANE (registered trade mark of MB) having a modulus of elasticity, measured under the conditions defined above, of 1.9MPa. Its elongation under a stress of 0.95MPa is just 20%. Its glass transition temperature Tg, measured by differential scanning calorimetry as defined above, was approximately -640C. The water permeability of a film of this adhesive was measured by a 11LYSSY11 apparatus. At 380C and 90% relative humidity this gave a water permeance of 6.98g/m 2 in 24h for a film having lmm thickness. Applying a correcting factor for the operational conditions and the film thickness gives a water permeability for the adhesive of approximately 1.17g x mm film thickness per m 2 x 24h x kPa water pressure. The adhesive is stable up to 1000C, showing substantially no loss of material up to that temperature. It further displays no loss of volatile solvents.

In manufacturing such a panel the butyl ribbon 22 was applied at 300C to the periphery of the smaller pane 12 by means of a roller with a guide which located it 4mm from the edge of the pane 12. The plaquette 18 was placed in the desired position and the pane 10 was then placed on the ribbon 22. After introduction of a hollow needle through the ribbon 22 to permit escape of air, the assembly was calendered to a total thickness of 9mm. A masking strip was applied to the periphery of the larger pane 10 after the calendering and the adhesive 26 was then inserted and allowed to polymerise.

Panels as described with reference to Figures 1 to 3 were subjected to a series of tests as follows to investigate their performance under different types of extreme conditions.

I. Altitude Test.

The panel was stored for 1 month at a reduced pressure equivalent to an altitude of 3000m. At the end of the 1 month period the gap between the panes had been deflected outwards - f 14 by less than 2mm at the centre of the panes. On returning to sea level pressures the original panel shape was fully restored.

II. High Humidity Test The panel was subjected to a humidity test according to the DIN 52344 test procedure. The dew point of the panel was approximately -50 0 C before the test and was unchanged by the test.

III. High Temperature Test The panel was placed in an oven at 105 0 C and held at that temperature for 1 hour. No condensation was detected within the space between the panels, indicating that no release of condensible components had occurred.

The version of panel shown in Figure 4 is substantially the same as that of Figures 1 to 3 but incorporates an aluminium edging strip 34 covering and protecting the upper edge of the pane 12 and the upper surface of the polyurethane 26. The edging strip 34 includes a projecting tongue portion 36 which is embedded in the polyurethane 26 to give the assembly additional strength.

X_ is The version of panel shown in Figure 5 has outer and inner glass panes 40 and 42 respectively, with no overlap at their upper edges. In this version the sealing spacer includes a hot-extruded butyl rubber strip 38 as the first element, a polyurethane strip 26 as the second element and a lead alloy foil 44 (of 0Amm thickness and 2.5mm width) between the two elements and in direct contact with both of'them. In this version the butyl rubber includes no core ribbon and no desiccant but the panel includes a desiccant plaquette of the kind described above in relation to Figure 1 reference 18. In a variation of this version (not illustrated) the foil 44 can be embedded in the butyl rubber strip 38.

Figures 6 and 7 similarly show panels with panes 40 and 42 having no overlap at their upper edges. In both of them the sealing spacer has the Figure 1 configuration, i.e. a butyl ribbon 22 and a polyurethane adhesive 26. The Figure 6 version has an aluminium edge strip 45 covering the upper edges of both panes 40 and 42 and alsothe adhesive 26. The strip 45 includes a tongue portion 46 embedded in the adhesive 26. The side faces of the upper part of the strip 45 curve inwards to form an upper ridge 48 shaped to slide easily into a corresponding groove on a door frame.

The Figure 7 version has an edge strip 50 with side portions 52 forming a generally U-shaped recess to receive the panes 40 and 42. The edge strip 50 can be formed of aluminium as such or of a polymeric material with an aluminium ribbon embedded in it. The side portions 52 have internal strands 54 of neoprene held in corresponding channels in their inside faces so as to form a water-impermeable joint with the glass surface. The strip 50 is held in place by the polyurethane 26 which in this version extends from the space adjacent to the ribbon 22, over the upper edges of the panes 40 and 42 and into the spaces between the side portions 52 and the outer surfaces of the panes 40 and 42. The upper part of the strip 16 is shaped to form a ridge portion 56, offset towards the inner side of the panel, to engage in the upper groove of a door frame.

A sample panel of the type described above with reference to Figures 1 to 3 was subjected to shearing tests as follows. After ageing treatment for 50 hours in water at 900C shearing of the sample adhesive produced cohesive rupture at 1.8MPa. After ageing for 70 days in water at 800C cohesive rupture was produced at 1MPa. By way of comparison, with a polysulphide adhesive having a modulus of elasticity under traction of 0. 9MPa, the 50 hour ageing test produced cohesive rupture at 0.7MPa and in the 70 day test the panel split apart before the end of the test period. No change was observed in the mechanical properties obtained before and after another shearing test of mechanical fatigue, executed on another sample, which comprised applying a recurrent shearing force to the sealing spacer equivalent to 40 times the-weight of one of the component glass sheets for about 100,000 cycles.

Thus with the specified elements of the sealing spacer, double glazing of this type is extremely resistant to very severe and highly variable atmospheric conditions and to shearing or tractive forces resulting in particular from variations in temperature, pressure or shock. It is therefore especially advantageous for use in automobile glazing.

I- 17

Claims

1. A multiple glazing panel for a vehicle, which panel comprises at least two panes of glass and a sealing spacer between the or each pair of adjacent panes so as to retain the panes in spaced relationship to each other, form a sealed space between them and extend around the periphery of the sealed space, characterised in that the or each sealing spacer comprises a first element in contact with both adjacent panes and with the sealed space, the said first element being formed of a flexible and malleable material and providing a barrier to entry of humidity into the sealed space, and a second element in contact with both adjacent panes and being at least partially formed of an adhesive having a modulus of elasticity greater than 1AMPa (measured as hereinbefore defined).

2. A multiple glazing panel as claimed in claim 1, in which the first element is at least partially formed of butyl rubber.

3. A multiple glazing panel as claimed in claim 2, in which the first element is in the form of a butyl rubber ribbon.

4. A multiple glazing panel as claimed in claim 3, in which the ribbon has a core formed of a thread selected from aluminium, cotton or synthetic fibres.

5. A multiple glazing panel as claimed in claim 3 or claim 4, in which the ribbon incorporates a desiccant.

6. A multiple glazing panel as claimed in any one of claims 2 to 5, in which a spacing strip is inserted between the panes and adjacent to the butyl rubber.

41 18

7. A multiple glazing panel as claimed in any one of claims 2 to 5, in which the first element includes a corrugated metallic strip embedded in butyl rubber or having butyl rubber on one or more of its faces.

8. A multiple glazing panel as claimed in any preceding claim, in which an insert containing a desiccant is included in the sealed space.

9. A multiple glazing panel as claimed in claim 8, in which the insert is located at a position in the space which is not normally visible to occupants of the vehicle.

10. A multiple glazing panel as claimed in claim 8 or claim 9, in which the insert is secured to the first element. t

11. A multiple glazing panel as claimed in any preceding claim, in which a microporous material is included in the first element to hinder the entry of water molecules into the sealed space while permitting passage of other gases.

12. A multiple glazing panel as claimed in claim 11, in which the microporous material is in the form of one or more pellets.

13. A multiple glazing panel as claimed in any preceding claim, in which the adhesive of the second element has a modulus of elasticity greater than 1.8MPa.

14. A multiple glazing panel as claimed in any preceding claim, in which the adhesive has a modulus of elasticity not greater than 4MPa.

15. A multiple glazing panel as claimed in any preceding claim, in which the adhesive of the second element is of a type which does not release volatile solvents.

w 4 19

16. A multiple glazing panel as claimed in any preceding claim, in which the adhesive of the second element is of a type which does not present a substantial loss of constituent material at temperatures below 1000C.

17. A multiple glazing panel as claimed in any preceding claim, in which the adhesive of the second element has a glass transition temperature Tg (measured by differential scanning calorimetry as defined above) of below -450C.

18. A multiple glazing panel as claimed in any preceding claim, in which the adhesive of the second element has a water permeability of less than 2.25g x mm of thickness per m 2 X 24h x kPa water pressure.

19. A multiple glazing panel as claimed in claim 18, in which the adhesive of the second element has a water permeability of less than 1.5g x mm of thickness per m 2 x 24h-x kPa water pressure.

20. A multiple glazing panel as claimed in any preceding claim, in which the adhesive of the second element is a polyurethane.

21. A multiple glazing panel as claimed in claim 20, in which the adhesive is a two-component polyurethane.

22. A multiple glazing panel as claimed in any preceding claim, in which at least one of the panes carries one or more anti-solar or low emissivity coatings.

23. A multiple glazing panel as claimed in any preceding claim, in which at least one of the panes is formed of laminated glass.

24. A multiple glazing panel as claimed in any preceding claim, comprising two panes which have the same outer shape but one of which is slightly smaller than the other.

k zt -a

25. A multiple glazing panel as claimed in claim 24, in which the alignment of the larger and smaller panes is such that the panel incorporates a step at the margin of one or more sides.

26. A multiple glazing panel as claimed in any preceding claim, in which a metallic or plastic edging strip is attached to one or more of the edges of the panel.

27. A multiple glazing panel as claimed in claim 26, in which the strip has a U-shaped construction.

28. A multiple glazing panel as claimed in claim 26 or claim 27, in which the strip is provided on the lower edge of-the panel.

29. A multiple glazing panel as claimed in any preceding claim, in which the distance between adjacent panes is in the range 1 to 4mm.

30. A multiple glazing panel as claimed in any preceding claim, in which the sealed space is filled with a special filler selected from one or more gases such as argon, SF 6 or krypton, or a material such as aerogel.

31. A multiple glazing panel as claimed in claim 1, substantially as described herein.

32. A method of manufacturing a multiple glazing panel for a vehicle window, which comprises inserting a sealing spacer between two adjacent panes of glass so as to locate the panes in spaced relationship to each other, wherein a first element of the sealing spacer, which element is formed of a flexible and malleable material, is placed on one face of one of the panes to form a continuous elongated strip extending around the margin of the face and close to its edge, the other pane is then placed on the first element and the panes are pressed 1 21 together until the interspace between them is reduced to a desired distance and to form a sealed space between the panes, and a second element, which is at least partially formed of an adhesive having a modulus of elasticity greater than 1AMPa (measured as hereinbefore defined), is then placed in contact with the panes around at least part of the first element so as to form a strong adhesive bond between the panes.

33. A method as claimed in claim 32, which includes first washing and drying the glass panes and then applying a butyl rubber ribbon to one of them to form the first element.

34. A method as claimed in claim 33, in which the butyl ribbon is aligned by means of a roller with a guide which permits a constant distance to be maintained from the edge of the pane.

35. A method as claimed in claim 33 or claim 34, in which the other pane is then positioned on the first element and a hollow needle is inserted through the butyl ribbon to permit the escape of air from the interspace during subsequent pressing of the second pane on to the first pane.

36. A method as claimed in any one of claims 32 to 35, in which assembly of the panes to form the panel is conducted with the assistance of a press having plates to which are attached inflatable bags which apply the requisite assembly pressure to the opposed faces of the panel.

37. A method as claimed in any one of claims 32 to 36, in which the panel includes panes of different sizes and a masking strip is placed around the margin of the inner face of the larger pane so as to avoid applying any of the second element adhesive to the said margin.

4 22 1

38. A method as claimed in any one of claims 32 to 37, in which a protective or decorative strip is added to one or more of the edges of the panel after insertion of the second element adhesive.

39. A method as described herein.

claimed in claim 32, substantially as Published 1990 atThePatentOfftce. State House. 6671 High Holbnrn.I.. ondonWC1R4TP.Further copies maybe obtained from The Patent =ice Sales Branch. St Mary Cray. Orpington. Kent BR5 3RD. Printed by Multiplex technIques ltd. St Mary erky. Kent. Con 187