Glazing panel

Abstract

 This invention relates to glazing panels, and in particular to vacuum insulating glazing panels and to a process for manufacturing such glazing panels. It is disclosed a glazing panel comprising two sheets of glass disposed in an opposing and spaced relationship with each other with a gap formed therebetween, the gap being a low pressure space having a pressure less than atmospheric pressure, a hermetic seal for sealing off said low pressure space, comprising an organic material, a plurality of spacers provided between said two sheets of glass for spacing the sheets of glass from one another, comprising an organic material, with a distance between the two sheets of glass is in the range 0.1 to 0.6 mm.

Description

[0001] This invention relates to glazing panels, and in particular to vacuum insulating glazing panels, and to a process for manufacturing such glazing panels.

[0002] Vacuum insulating glazing panels typically comprise two spaced apart sheets of glass, having a "vacuum", i.e. a low pressure space at a pressure less than atmospheric, arranged between them. These sheets are interconnected by a peripheral joint and an array of supporting pillars, also called spacers.

[0003] There are several difficulties to address in the design and production of low pressure evacuated windows: for example, to achieve a low level of vacuum and maintain it over a long period of time, it is necessary to make a seal around the perimeter of the window using materials which have extremely low permeability to gases and negligible outgassing over long periods of time. In addition, an array of supports must generally be provided between the sheets of glass to ensure sufficient mechanical strength to withstand atmospheric pressure and maintain the sheets of glass spaced apart. These supports or spacers may lead to localised concentrations of mechanical stress in the glass, and in the supports themselves, which may increase the danger of breakage. Furthermore, the mechanical supports may act as points of thermal conduction through the window.

[0004] A low emissivity (low-E) coating may be provided on one or both sheets of glass, for example on the interior surface (i.e. the surface facing the low pressure space or gap between the glass sheets) of one or both sheets of glass. The emissivity of such coating is usually at most 0.2. This may lead to a further difficulty in the design and production of vacuum insulating glazing panels, as the materials forming the peripheral seal and/or the spacers should be compatible with the low-E layer, i.e. the layer should not be damaged or its performance reduced when contacted by the materials forming the peripheral seal and/or the spacers or merely by vapours which may come from these materials.

[0005] According to some of its aspects, the present invention provides a glazing panel as defined by claim 1 and claim 3. Other claims define preferred and/or alternative aspects of the invention.

[0006] Providing the defined combination of hermetic seal and spacers in a vacuum insulating glazing panel may provide an advantageous combination of properties. The present invention may provide an advantageous combination of:

■ Hermetic sealing: the organic material forming the hermetic seal may afford low permeability to gases and negligible outgassing over long periods of time.

■ Structural solidity: the organic material and/or any inorganic charge comprised in the spacers and the hermetic seal, may help to ensure the necessary spacing between the glass sheets and may help to avoid localised concentrations of mechanical stress in the glass, and in the supports themselves. This may reduce the risk of breakage.

■ Thermal insulation: a vacuum insulating glazing panel according to the invention may show thermal insulation performance at least equivalent to a double-glazing panel incorporating two sheets of glass separated by a gap filled with gas, while being of a lighter and thinner structure than such a double-glazing. The presence of a low-E coating may further improve this thermal insulation performance. The fact that the spacers comprise an organic material may reduce or avoid thermal conduction through the spacers, in comparison with known spacers of, for example, metals.

■ Compatibility with a low-E coating layer: the organic material may avoid or reduce any danger of damage to the low-E layer.

■ Aesthetic appearance: organic materials may provide aesthetic advantages, for example being less visible or more discreet than other known materials for the spacers.

[0007] Glazing panels according to the invention preferably present a distance between the two sheets of glass in the range 0.1 to 0.6 mm, preferably over substantially the whole surface of the glazing panel. This distance may be maintained by means of the spacers, and/or by means of the hermetic peripheral seal. The spacers preferably comprise an organic material, or alternatively, consist essentially of an organic material, or consist of an organic material. The nature of the spacers and the spacing between them are such that they may prevent the two glass sheets from moving closer to each other under atmospheric pressure. Examples of convenient organic materials for the spacers are epoxy materials (for example DELO-KATIOBOND VE 13900, BISON), acrylate materials (for example DELO-PHOTOBOND 4468, CONLOC), butyl materials, polyurethane materials, polysulfide materials, acrylic materials and mixtures of one or more thereof (for example mixtures of urethane and acrylate, e.g. DELO-PHOTOBOND GB350, DELO-PHOTOBOND GB368, or mixtures of urethane and metacrylate, e.g. LOCTITE 350, LOCTITE 366, LOCTITE 661).

[0008] In some embodiments, the spacers do not adhere to either of the glass sheets, but preferably, at least some of the spacers, and more preferably all the spacers, adhere to at least one of the glass sheets. This may be advantageous in that the spacers will remain in place if the vacuum insulating glazing panel ages, loses its vacuum qualities or if the glass sheets move apart from each other.

[0009] Preferably, the spacers have a diameter of less than 3 mm, less than 2 mm, or less than 1.5 mm. These values may offer a good mechanical resistance and/or an acceptable thermal conductivity whilst being aesthetically discreet.

[0010] The glass sheets may be sealed together along their edges with a hermetic seal comprising an organic material or alternatively, consisting essentially of an organic material, or consisting of an organic material. Convenient organic materials for the seal may be the same as those described hereinabove for the spacers. Preferably, the organic material used in the sealing of the glass sheets is the same as the material used for the spacers. This may facilitate manufacture as a single material may be used on the production line. In some embodiments, the hermetic seal may be made of two or more individual seals, of which at least one comprises an organic material. For example, the hermetic seal may be made of an internal seal comprising butyl material and an external seal comprising epoxy material; it may also include a median seal, between the internal and external seals, incorporating a desiccant material. The internal seal of butyl may afford the advantage of being compatible with a low-E layer, and the external seal of epoxy may offer good resistance to ageing.

[0011] Preferably, the distance between the two sheets of glass is in the range 0.1 to 0.6 mm, more preferably in the range 0.1 to 0.3 mm or 0.15 to 0.25 mm. These values may offer good thermal insulation properties to the vacuum insulating glazing panel.

[0012] At least some of the spacers may comprise a charge, for example a mineral charge, adapted to maintain or to assist in maintaining the spacing between the sheets of glass. The hermetic peripheral seal may also comprise such a charge. The charge may for example comprise alumina, e.g. corundum, and/or zirconium. The organic material may have a mechanical resistance adapted and sufficient to maintain the sheets of glass spaced apart without a charge, so that a predetermined quantity of organic material allows maintenance of the desired distance between the two glass sheets.

[0013] The spacers may be arranged linearly or in alternate rows. Alternatively, they may be arranged without any particular organisation or be more numerous in one portion of the glazing panel and less in another, for example they may be less numerous in the central vision portion of the glazing panel. The distance between the spacers is preferably equal to or greater than 1, 2, 3 or 4 cm and equal to or less than 10, 8, or 6 cm, more preferably between 1 and 10 cm and still more preferably between 4 and 6 cm. Such ranges of distances between the spacers may provide insulating glazing panels with a maintained distance between the two sheets of glass. By "distance between the spacers" it is meant herein the distance between at least 50% of the spacers, or preferably between at least 75% of the spacers, or still more preferably, the distance between all of the spacers. This means that, for example, at least 50% of the spacers do not have another neighbouring spacer inside a circle of which they are the central point and which has a radius equal to the distance between the spacers.

[0014] In a preferred embodiment, the thickness of each of the two sheets of glass is in the range 2 to 6 mm, preferably 3 to 5 mm, and more preferably of the order of 4 mm. The two sheets of glass may be of the same thickness or have different thicknesses.

[0015] A surface of each of the two sheets of glass may be coated with a low emissivity layer, in particular the surfaces facing the space between them. One of the glass sheets may, for example, be coated with a low-E layer on its surface facing the low pressure space. The low emissivity layer may be deposited by known techniques including vacuum deposition or chemical vapour deposition. Examples of convenient low-E coatings are sputtered coating stacks of the type dielectric/silver/dielectric, fluorine doped tin oxide layers. The glass surface provided with the low emissivity coating layer may have an emissivity of less than 0.3, less than 0.2 or preferably less than 0.1.

[0016] Vacuum insulating glazing panels according to the invention may be incorporated in multiple glazing panels, for example in a double glazing panel wherein it is associated with a further sheet of glass, such that the vacuum insulating glazing panel and the further sheet of glass are spaced apart from each other and sealed together along their edges and wherein the space between them is filled with gas.

[0017] Vacuum insulating glazing panels according to the invention preferably show a thermal transmittance, i.e. a U value, of at most 2.6 W/m².K, preferably at most 2.2, at most 1.9, at most 1.5 or at most 1.1 W/m².K.

[0018] Preferably, vacuum insulating glazing panels according to the invention satisfy standardised Fogging and CEN tests. The Fogging test is described in Annex C of European Standard EN 1279-6:2002. Its purpose is to verify that no unacceptable condensation appears inside the glazing panel due to emission of volatile substances. The CEN test is described in European Standard EN 1279-2:2002. It simulates ageing of an insulating glass unit and tests the humidity rate inside the glazing panel. The humidity rate is measured for example with the parameter "dew point temperature" (see Annex A of EN 1279-2:2002). Preferably, vacuum insulating glazing panels according to the invention do not show visible permanent condensation after the Fogging test and/or show a dew point temperature of less than -30°C after the CEN test.

[0019] According to another aspect, the present invention provides a process for manufacturing a vacuum insulating glazing panel as defined by claim 18.

[0020] In a preferred embodiment, a sheet of glass is profiled (for example by grinding) on at least one portion of at least one of its edges, for example, to form a chamfered edge. Alternatively, one entire edge or the entire periphery of the glass sheet may be profiled. A groove may be provided in a surface of this sheet of glass, extending from the profiled edge portion, for example perpendicularly to the edge of the glass sheet. This groove may have for example a length in the range of 1 to 5 cm and a width in the range of 0.1 to 2 mm. The groove may be adapted to receive a capillary tube, preferably made of glass. The length of the groove may be such as being the least visible whilst allowing a capillary tube to be positioned therein. The width of the groove may be chosen according to the diameter of the capillary tube and the spacing desirable between the two glass sheets of the vacuum insulating glazing. The capillary tube is positioned so that it extends outside of the glass sheet surface. Preferably, the end of the capillary tube which extends outside of the glass sheet surface has a funnel shape which may be adapted to a pumping apparatus. The capillary tube may be maintained in the groove with the presence of an organic material of the type described for the spacers according to this invention, or any adhesive material. The spacers and the hermetic seal may be deposited on the same surface of the same glass sheet or on a surface of the other glass sheet. It may be preferred that all these operations are made on the same glass sheet for easiness on the production line. It may also be preferred, for the same reason, to use the same organic material for the spacers, the hermetic seal and for maintaining the capillary tube in the groove.

[0021] After all these steps, a second sheet of glass may be placed in an opposing and spaced relationship with the first sheet of glass with a gap, the spacers, the hermetic seal and the capillary tube therebetween. The first and second glass sheets may have different size. The second sheet of glass may also be profiled on at least one portion of at least one of its edges or on an entire edge or on its entire periphery. Preferably the profiled portion of the second glass sheet is placed in front of the profiled portion of the first glass sheet. The glass sheets may then be pressed together and treated under specific temperatures or under UV rays, for example, so that the organic material, if necessary, may polymerise.

[0022] In a next step, a vacuum, i.e. an environment of less than the atmospheric pressure, is created between the sheets of glass by pumping out gases through the capillary tube. Preferably the vacuum level between the sheets of glass is in the range 10^-3 to 10^-6 bar, preferably in the range 10^-4 to 10^-5 bar. Preferably the pumping-out phase is made under an ambient temperature of between 40 and 160 °C, preferably between 50 and 80 °C. This may facilitate the desorption of the glazing panel. The capillary tube may then be sealed and broken, so that it no longer extends outside of the glass sheets surfaces, for example by heating and bending it, in particular when it is made of glass. The zone where the broken end of the capillary tube is exposed may further be provided with an organic material, for example of the type used for the spacers.

[0023] This method may have the advantage of avoiding the presence of a hole in one of the glass sheet, which was previously necessary for the pumping-out process. It may also be advantageous in that the system is very discreet and may be hidden by the frame of the finished window, when the vacuum insulating glazing panel is incorporated in such a window.

[0024] Embodiments of the invention will now be described, by way of example only, with reference to figures 1 to 5, and to example 1. Figure 1 shows a glazing panel according to the present invention. Figure 2 shows a transversal view through the glazing panel of figure 1 along line A-A'. Figure 3 shows a portion of a glazing panel according to the present invention fitted with the capillary tube for the pumping out process. Figures 4 and 5 show transversal views through the glazing panel of figure 3 along line B-B' at different stages of the glazing manufacture. The drawings are not to scale.

[0025] Figure 1 and 2 show a glazing panel 1 comprising two sheets of glass 2 and 2' disposed in an opposing and spaced relationship with a gap 3 formed therebetween, the gap being a low pressure space having a pressure less than atmospheric pressure. This low pressure space is sealed off with a hermetic seal 4 positioned at or towards and running around the periphery of the glazing. The glazing panel is provided with a plurality of spacers 5 between the two sheets of glass 2 and 2'. In these figures, the spacers are arranged linearly and form an array of spacers with a regular interval between them.

[0026] Figures 3, 4 and 5 illustrate a process of manufacturing a vacuum insulating glazing panel according to the invention. In this particular example, both glass sheets have chamfered edges 6 and 6'. A groove 7 is present at the surface of one of the glass sheet and a capillary tube 8 is positioned in the groove where it is maintained with an organic material, represented in the figures by the hatching. Figures 3 and 4 show the system while gases are being pumped out through the capillary tube, and figure 5 shows the finished glazing panel.

Example 1

[0027] A sheet of glass of 4 mm thickness with a dimension of 1 x 1 m is provided with a low emissivity coating layer. The layer consists of the following coating stack: TiO_x/ZnO_x/Ag/TiO_x/ZnO_x/SnO_x. The edges of the sheet of glass are chamfered in such a way that the coated surface of the glass sheet is smaller than the other surface. On one edge of the glass sheet a groove is made at the coated surface of the glass sheet. The groove is made perpendicularly to the edge of the glass sheet with a length of 2 cm, a width of 1 mm and a depth of about 2 mm. A capillary tube, made of glass, is placed in the groove in a manner represented in figures 3 and 4. The capillary tube is maintained in the groove by placing an organic material around it. This material is a modified urethane acrylate, available from the company DELO under the name DELO-PHOTOBOND GB350. Attention should be given to the fact that the capillary tube should not be obstructed by the organic material. Spacers of DELO-PHOTOBOND GB350 comprising a corundum core are deposited on the coated side of the sheet of glass, linearly in an array, with a regular interval between the deposits of 5 cm and a seal of DELO-PHOTOBOND GB350 is positioned at the periphery of the glass sheet.

[0028] A second sheet of glass of 4 mm thickness with a dimension of 1 x 1 m and with chamfered edges is placed over the first glass sheet in a manner represented in figure 4. The glass sheets are pressed together and placed under an UV-light for the curing of the DELO-PHOTOBOND GB350.

[0029] After curing, a pumping apparatus is connected to the capillary tube and gas present between the two sheets of glass is evacuated to create a vacuum of about 10^-4 bar. This operation is carried out at an ambient temperature of approximately 70°C. The capillary tube is then heated, bended, sealed and broken in the space created by the chamfered edges of the glass sheets, as represented in figure 5, and this space is filled with DELO-PHOTOBOND GB350. The glazing panel is then placed again under an UV-light for the curing of the DELO-PHOTOBOND GB350.

[0030] This vacuum insulating glazing panel may then incorporated in a double-glazing, where it is associated with a glass sheet of 4 mm thickness and with a gap filled with gas between them. The structure of this double-glazing is thus:

glass (4 mm) / gas / glass (4 mm) / vacuum / low-E layer / glass (4 mm).

This double-glazing panel may be incorporated in a window frame and placed preferably with the vacuum insulating glazing panel on the indoor side.

Claims

1. A vacuum glazing panel comprising

■ two sheets of glass disposed in an opposing and spaced relationship with each other with a gap formed therebetween, the gap being a low pressure space having a pressure less than atmospheric pressure,

■ a hermetic seal for sealing off said low pressure space, comprising an organic material,

■ a plurality of spacers provided between said two sheets of glass for spacing the sheets of glass from one another, comprising an organic material,

wherein the distance between the two sheets of glass is in the range 0.1 to 0.6 mm and at least one of the sheets of glass is coated on at least one of its faces with a low emissivity coating layer.

2. A vacuum glazing panel according to claim 1, wherein at least some of the spacers adhere to at least one of the glass sheets.

3. A vacuum glazing panel comprising

■ two sheets of glass disposed in an opposing and spaced relationship with each other with a gap formed therebetween, the gap being a low pressure space having a pressure less than atmospheric pressure,

■ a hermetic seal for sealing off said low pressure space, comprising an organic material,

■ a plurality of spacers provided between said two sheets of glass for spacing the sheets of glass from one another, comprising an organic material,

wherein the distance between the two sheets of glass is in the range 0.1 to 0.6 mm and the spacers do not adhere to at least one of the glass sheets.

4. A vacuum glazing panel according to any of the preceding claims, wherein the organic material of the hermetic seal and the spacers is the same.

5. A vacuum glazing panel according to any of the preceding claims, wherein the organic material is selected from the group consisting of epoxy materials, acrylate materials, butyl materials, polyurethane materials, polysulfide materials, acrylic materials and mixtures of one or more thereof.

6. A vacuum glazing panel according to any of the preceding claims, wherein at least some of the spacers, or the hermetic seal, or both comprise a charge adapted to maintain the spacing between the sheets of glass.

7. A vacuum glazing panel according to claim 6, wherein the charge is a mineral charge.

8. A vacuum glazing panel according to claim 7, wherein the charge is selected from the group consisting of alumina and zirconium.

9. A vacuum glazing panel according to any of the preceding claims, wherein the distance between the two sheets of glass is in the range 0.15 to 0.25 mm.

10. A vacuum glazing panel according to any of the preceding claims, wherein the hermetic seal comprises two or more individual seals.

11. A vacuum glazing panel according to any of the preceding claims, wherein the spacers are arranged with a distance between them of between 1 and 10 cm.

12. A vacuum glazing panel according to claim 11, wherein the distance between the spacers is between 4 and 6 cm.

13. A vacuum glazing panel according to any of the preceding claims, wherein the thickness of each of the two sheets of glass is in the range 2 to 6 mm.

14. A vacuum glazing panel according to any of the preceding claims, wherein the glazing panel shows no visible permanent condensation after the Fogging test according to European Standard EN 1279-6:2002.

15. A vacuum glazing panel according to any of the preceding claims, wherein the glazing panel has a dew point temperature of less than -30°C after the CEN test according to European Standard EN1279-2:2002.

16. A vacuum glazing panel according to any of the preceding claims, wherein the glazing panel has a U value of at most 1.9 W/m².K

17. A double glazing panel incorporating a vacuum glazing panel according to any of the preceding claims and a further spaced sheet of glass, wherein the sealed space between them is filled with gas.

18. A process for manufacturing a vacuum insulating glazing panel comprising the steps of

- providing a first sheet of glass

- providing a groove in a surface of said sheet of glass extending from an edge of the sheet of glass

- depositing spacers on said surface of the glass sheet

- depositing an hermetic seal on said surface of the glass sheet

- depositing a capillary tube in the groove so that it extends outside of the glass sheet surface and ensuring that it is maintained in the groove

- placing a second sheet of glass in an opposing and spaced relationship with the first sheet of glass with a gap, the spacers, the hermetic seal and the capillary tube therebetween

- creating a vacuum between both sheets of glass by pumping out gases through the capillary tube

- breaking the portion of the capillary tube which extends outside of the glass sheets surfaces

- closing the capillary tube at its broken end.

19. A process according to claim 18, wherein the first sheet of glass has at least one portion of one edge profiled and that the groove extends from this profiled edge portion.

20. A process according to any of claims 18 or 19, wherein the spacers and/or the hermetic seal comprise an organic material.

21. A process according to any of claims 18 to 20, wherein the capillary tube is maintained in the groove with an organic material.

22. A process according to any of claims 18 to 21, wherein the capillary tube is made of glass.

23. A process according to any of claims 18 to 22, wherein the broken end of the capillary tube is surrounded by an organic material.

24. A process according to any of claims 18 to 23, wherein the organic material used in the spacers, the hermetic seal, the groove and for surrounding the broken end of the capillary tube is the same.

25. A process according to any of claims 20 to 24, wherein after having placed the second sheet of glass over the first one, the glass sheets are pressed together and the organic material is allowed to polymerise.

Drawing