WO2023041456A1

WO2023041456A1 - Multiple glazing with asymmetric vacuum-insulating glazing unit

Info

Publication number: WO2023041456A1
Application number: PCT/EP2022/075206
Authority: WO
Inventors: Julien JEANFILS; Olivier Bouesnard
Original assignee: Agc Glass Europe
Priority date: 2021-09-15
Filing date: 2022-09-12
Publication date: 2023-03-23

Abstract

The present invention concerns a multiple glazing (10) extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Y comprising at least : a. a vacuum insulating glazing unit comprising:i. a first glass pane, GP1, having a thickness Z1, and having an inner pane face (11) and an outer pane face (12)and a second glass pane, GP2, having a thickness, Z2, and having an inner pane face (21) and an outer pane face (22). The thicknesses are measured in the direction normal to the plane, P;ii. a set of discrete spacers (3) positioned between the first and the second glass panes, maintaining a distance between the first and the second glass panes; iii. a hermetically bonding seal (4) sealing the distance between the first and the second glass panes over a perimeter thereof; iv. an internal volume, V, defined by the first and the second glass panes and the set of discrete spacers and closed by the hermetically bonding seal and wherein there is a vacuum having a pressure of less than 0.1 mbar; and wherein the inner pane faces face the internal volume, V; b. a third glass pane, GP3, having an inner pane face (31) and an outer pane face (32); and c. a peripheral spacer (6) positioned between the outer pane face (22) of the second glass pane, GP2, and the inner pane face (31) of the third glass pane, GP3, over a perimeter thereof, that maintains a distance there between. The peripheral spacer (6), the outer pane face (22), and the inner pane face (31) define an internal space, Sp. The thickness ratio, Z1/Z2, of the thickness of the first glass pane, Z1, to the thickness of the second glass pane, Z2, is equal to or greater than 1.10 (Z1 / Z2 ≥ 1.10), and the second glass pane, GP2, is facing the internal space, Sp.

Description

Multiple Glazing with asymmetric vacuum-insulating glazing unit

1. Field of the invention

[0001] The invention relates to a multiple glazing that comprises a vacuum insulating unit wherein the first and second glass panes are of different thicknesses and are specifically positioned within the glazing so that the thinner glass pane faces the internal space of the multiple glazing.

2. Background of the invention

[0002] Multiple glazing such as double glazing or even triple glazing, is a very traditional answer to provide thermal insulation. Double glazing typically comprises two glass panes coupled along their periphery by a peripheral spacer creating an internal space sealed by a peripheral edge seal. Said peripheral spacer maintains a certain distance between the two glass panes. In general, said internal space is filled with air and/or an inert gas, to further lower heat transfer and/or reduce the sound transmission.

[0003] Current window frames have been designed with a rabbet of a certain size to incorporate these double or even triple glazing structures. If improved thermal insulation is further sought, such multiple glazing can be altogether replaced by vacuum insulating glazing. A vacuum-insulating glazing unit is typically composed of at least two glass panes separated by an internal volume in which a vacuum has been generated. In general, in order to achieve a high-performance thermal insulation (Thermal transmittance, Ug, being Ug<1.2 W/m²K) the absolute pressure inside the glazing unit is typically 0.1 mbar or less and generally at least one of the two glass panes is covered with a low- emissivity layer.

[0004] However, replacing current multiple glazing by vacuum insulating glazing is problematic since vacuum insulating glazing are much thinner than multiple glazing and do not use the full space provided by the window frame's rabbet. One solution provided in that art is represented by WO2014/039642 that proposes that the vacuum insulating glazing unit is supported on one side by a portion of the frame and on the other side by a spacer structure. Another existing solution described in W02007/075298, proposes to add an additional glass pane fixed into the frame.

[0005] Still another solution is to replace one of the glass panes of the multiple glazing by a vacuum insulating glazing unit so that the technical problem of unnecessary frame's rabbet space does not happen. EP860406A discloses a double glazing comprising one or two vacuum insulating glazing unit(s). However such configuration generates other technical problems. Indeed, it was expected that the vacuum insulating glazing unit would behave mechanically within a multiple glazing as a single pane since the internal volume of the vacuum insulating glazing unit is very thin and since both glass panes are strongly coupled by the hermetically bonding seal. However, it has been surprisingly found that the vacuum insulating glazing unit within a multiple glazing demonstrates very different mechanical and thermal performances.

[0006] Vacuum insulating glazing are carefully dimensioned to resist to different external loads. A major load to be considered is the load induced by a temperature difference between exterior and interior environments. Indeed, the glass pane facing the interior environment, takes up a temperature similar to the temperature of the interior environment and the glass pane facing the exterior environment, takes up a temperature similar to the temperature of the exterior environment. In most stringent weather conditions, the difference between the interior and the exterior temperatures can reach 40°C and more. The temperature difference between the interior and the exterior environments may cause stress inside the glass panes and in some severe cases, may lead to fracture of the vacuum-insulating glazing unit. Therefore, it is critical to control the level of thermal induced stress.

[0007] Such technical problem of thermal induced stress has been addressed in JP2001316137 which addresses how to improve vacuum insulating glazing so that no deformation nor distortion occurs even if the glass panes are hit by strong sunlight. JP2001316137 teaches to design a glazing wherein the inner glass pane disposed on the indoor side is thicker than the outer glass pane. In contrast, JP2001316138 teaches the opposite VIG construction wherein the outer glass pane disposed on the outdoor side is thicker than the inner glass pane, for improved chock resistance and acoustic.

[0008] None of the art addresses the technical problem of controlling the level of induced thermal stress of vacuum insulating glazing units when incorporated into multiple glazing.

SUMMARY OF THE INVENTION

[0009] The present invention relates to a multiple glazing extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Y comprising at least : a. a vacuum insulating glazing unit comprising: i. a first glass pane, GP1, having a thickness Zl, and having an inner pane face and an outer pane face and a second glass pane, GP2, having a thickness, Z2, and having an inner pane face and an outer pane face. The thicknesses are measured in the direction normal to the plane, P; ii. a set of discrete spacers positioned between the first and the second glass panes, maintaining a distance between the first and the second glass panes; ill. a hermetically bonding seal sealing the distance between the first and the second glass panes over a perimeter thereof; iv. an internal volume, V, defined by the first and the second glass panes and the set of discrete spacers and closed by the hermetically bonding seal and wherein there is a vacuum having a pressure of less than 0.1 mbar; and wherein the inner pane faces face the internal volume, V; b. a third glass pane, GP3, having an inner pane face and an outer pane face; and c. a peripheral spacer positioned between the outer pane face of the second glass pane, GP2, and the inner pane face of the third glass pane, GP3, over a perimeter thereof, that maintains a distance there between. The peripheral spacer, the outer pane face of the second glass pane, GP2, and the inner pane face of the third glass pane, GP3, define an internal space, Sp.

The thickness ratio, Z1/Z2, of the thickness of the first glass pane, Zl, to the thickness of the second glass pane, Z2, is equal to or greater than 1.10 (Zl / Z2 > 1.10). The second glass pane, GP2, is facing the internal space, Sp.

[0010] In a preferred embodiment, the vacuum insulating glazing unit has a thickness ratio, Z1/Z2, of the thickness of the first glass pane, Zl, to the thickness of the second glass pane, Z2, equal to or greater than 1.20 (Z1/Z2 > 1.20); preferably equal to or greater than 1.30 (Z1/Z2 > 1.30), preferably equal to or greater than 1.50 (Z1/Z2 > 1.50), preferably equal to or greater than 1.55 (Z1/Z2 > 1.55), more preferably equal to or greater than 1.60 (Z1/Z2 > 1.60). In a preferred embodiment, the vacuum insulating glazing unit has a thickness ratio, Z1/Z2, of the thickness of the first glass pane, Zl, to the thickness of the second glass pane, Z2, lower than or equal to 6.00 (Z1/Z2 < 6.00), lower than or equal to 4.00 (Z1/Z2 < 4.00), lower than or equal to 2.50 (Z1/Z2 < 2.50). In a more preferred embodiment, the vacuum insulating glazing unit has a thickness ratio, Z1/Z2 comprised between 1.20 and 1.60 (1.20 < Z1/Z2 < 1.60), preferably between 1.30 and 1.60 (1.30 < Z1/Z2 < 1.60).

[0011] In a preferred embodiment, the thickness of the second glass pane, Z2, is comprised between 1 mm and 8 mm (1 mm < Z2 < 8 mm), preferably between 2 mm and 6 mm (2 mm < Z2 < 6 mm). In a preferred embodiment, the thickness of the first glass pane, Zl, is comprised between 2 mm and 10 mm (2 mm < Zl < 10 mm), preferably between 3 mm and 8 mm (3 mm < Zl < 8 mm). [0012] In a preferred embodiment, at least one of the inner pane face of the third glass pane, the outer pane face of the third glass pane, the outer pane face of the second glass pane and/or the outer pane face of the first glass pane is laminated to at least a glass sheet by a polymer interlayer to form a laminated glass pane. Preferably, the outer pane face of the first glass pane is laminated to at least a glass sheet by a polymer interlayer to form a laminated glass pane.

[0013] Preferably, the glass sheet has a thickness Zs measured in the direction normal to the plane, P; comprised between 1mm and 8mm (1mm < Zs < 8mm), preferably between 1mm and 6mm (1mm < Zs < 6mm), more preferably 2mm and 4mm (2mm < Zs < 4mm), preferably equals 4mm (Zs = 4 mm). It is further preferred that the thickness of the first, second and/or third glass pane and the thickness of the glass sheet are different (Zl, Z2 and/or Z3 * Zs).

[0014] In a more preferred embodiment, third glass pane has a thickness, Z3, measured in the direction normal to the plane, P; comprised between 4mm and 8mm (4mm < Z3 < 8mm), preferably between 4mm and 6mm (4mm < Z3 < 6mm), and wherein the third glass pane is laminated to a glass sheet having a thickness Zs comprised between 4mm and 8mm (4mm < Zs < 8mm), preferably between 4mm and 6mm (4mm < Zs < 6mm), preferably by an acoustic PVB polymer interlayer. It is even further preferred that the thickness of the third glass pane and the thickness of the glass sheet are different (Z3 * Zs).

[0015] In a preferred embodiment, the multiple glazing comprises further at least a functional coating, preferably a heat ray reflection coating or a low-emissivity coating, on at least one of the glass panes face or glass sheet faces, preferably, on the inner pane faces of the first and/or second glass pane(s) and/or of the inner pane face of the third glass pane.

[0016] In one preferred embodiment of the present invention, one glass pane of the multiple glazing is prestressed glass. In one embodiment, it is preferred that the first glass pane and/or the third glass pane is prestressed glass. In another embodiment, it is preferred that the second glass pane is prestressed glass.

[0017] In a preferred embodiment, the set of discrete spacers forms an array having a pitch comprised between 15 mm and 80 mm, preferably between 15 mm and 50 mm and more preferably between 15 and 40 mm, more preferably between 15mm and 25mm and even more preferably is about 20mm. [0018] In a preferred embodiment, the first glass pane has a coefficient of linear thermal expansion, CTE1, and the second glass pane has a coefficient of linear thermal expansion, CTE2, and wherein the absolute difference between CTE1 and CTE2 is at most 1.2 10-6/°C ( | CTE1-CTE2 | < 1.2 10-6/°C), preferably is at most 0.8 10-6/°C ( | CTE1-CTE21 < 0.8 10-6/°C), more preferably at most 0.4 10-6/°C ( | CTE1-CTE21 < 0.4 10-6/°C) , more preferably at most 0.2 10-6/°C ( | CTE1-CTE21 < 0.2 10-6/°C) even more preferably equals 0 ( | CTE1-CTE21 = 0 /°C).

[0019] In a preferred embodiment, the peripheral spacer is a thermally improved spacer having a thermal conductance value of < 0.007 W/K calculated according to EN10077-1 annex E.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 shows a cross sectional view of a multiple glazing according to one embodiment of the present invention. It comprises a single pane and an asymmetric vacuum insulating glazing unit wherein the thinner glass pane faces the internal space of the multiple glazing.

DETAILED DESCRIPTION

[0021] The objective of the present invention is to provide a multiple glazing comprising a vacuum insulating glazing unit, that demonstrates reduced thermal induced stress.

[0022] The vacuum insulating glazing unit will be hereinafter referred to as the "VIG". The present invention will be herein described further by reference to a double glazing assembly comprising a VIG and a single glass pane but could be extended to any multiple glazing comprising one or more VIG(s) and one or more single glass pane(s). Another common multiple glazing is a triple glazing assembly comprising one or two VIG(s). All technical features and preferred technical features described herein further in relation to the double glazing can be applied to triple and any other multiple glazing.

[0023] In use, glazing are typically used to close the partition separating an interior space from a exterior space. The temperature of the interior space is typically from 20 to 25°C whereas the temperature of the exterior space can extend from -20°C in the winter to +35°C in the summer. Therefore, the temperature difference between the interior space and the exterior space can typically reach more than 40°C in severe conditions.

[0024] In the present invention, the VIG within the multiple glazing is separating a space A, characterized by a temperature, TempA, from the internal space of the double glazing unit characterized by an internal temperature, Tempint. If the VIG is positioned so that its first glass pane, GP1, is facing the first space, A, the temperature of said first glass pane (Tl) will adjust with the temperature of the first space (TempA). Similarly, the third glass pane, GP3, is separating a space B, characterized by a temperature, TempB from the internal space. The temperature of said third glass pane, (T3) will adjust with the temperature of the second space (TempB). The temperature (T2) of the second glass pane, GP2, facing the internal space will adjust with the temperature of the internal space (Tempint).

[0025] Typically for double glazing, the temperature of the internal space (Tempint) was expected to reach a mean temperature between TempA and TempB, slightly affected by solar radiation. It has been surprisingly found that in a double glazing wherein at least one of the single glass panes has been replaced by a VIG, the temperature of the internal space (Tempint) is strongly affected by solar radiation and can reach a much higher temperature than TempA and TempB.

[0026] Thermal induced stress occurs as soon as there is a temperature difference between the first glass pane (GP1 and Tl) and the second glass pane (GP2 and T2) and increases with increasing differences between Tl and T2. The temperature difference (AT) is the difference between the mean temperature Tl calculated for the first glass pane, GP1, and the mean temperature T2 calculated for the second glass pane, GP2. The mean temperature of a glass pane is calculated from numerical simulations known to the skilled people. Thermal induced stress becomes problematic - up to potential breaking of the VIG, when the absolute value of the temperature difference ( | AT | ) between the glass panes, reaches 20°C and becomes critical when such absolute value of the temperature difference reaches 30°C and even more when it reaches 40°C in severe conditions.

[0027] It has been further found that when the VIG is included into a multiple glazing, such absolute value of the temperature difference between the glass panes ( | AT | ) can reach even higher values than the corresponding temperature difference typically reached in a stand-alone VIG.

[0028] The table below shows data (from the location of Uccle, Belgium) wherein the absolute value of the temperature difference ( | AT | ) in the summer is much higher for the VIG within the multiple glazing than for the stand-alone VIG. The outside temperature can reach 35°C in summer and -10°C in winter for a temperature of 20°C inside the building. The absolute value of the temperature difference ( | AT| ) would therefore amount to about 14°C in summer and about 27°C in winter for a stand-alone VIG. When the VIG is configurated as a double glazing, the temperature in the internal space (Tempint) can reach 70°C in summer and 0°C in winter. Therefore, the absolute value of the temperature difference ( | AT| ) faced by the VIG within the multiple glazing, would amount to 37°C in summer and 20°C in winter. It can be seen from these data, that for a VIG within a multiple glazing, the absolute value of the temperature difference ( | AT| ) in summer is much higher than the absolute value of the temperature difference ( | AT| ) for the stand-alone VIG. In contrast, for a VIG within a multiple glazing, the absolute value of the temperature difference ( | AT | ) in winter is lower than the absolute value of the temperature difference ( | AT | ) of the stand-alone. Therefore, the reverse situation of the absolute value of the temperature difference ( | AT | ) in summer and in winter requires a significant paradigm change in the design of the glazing, to control the thermal induced stress.

[0029] The table below illustrates the temperature difference (AT) being the difference between the mean temperature T1 calculated for the first glass pane, GP1, and the mean temperature T2 calculated for the second glass pane, GP2.

[0030] Therefore, when incorporated into a multiple glazing, the VIG must be carefully dimensioned to resist to the thermal induced stress specific to its environment of use and to the multiple glazing configuration. In particular, it has been found that the asymmetry of glass thickness of the VIG can address the technical challenge of acute thermal induced stress, when positioned in a specific orientation. Indeed, it has been surprisingly found that the asymmetric VIG should be incorporated into the multiple glazing so that the thinner glass pane is facing the internal space of the multiple glazing.

[0031] The thermal induced stress has been tested and compared in 3 different double glazing configurations that have been placed in buildings at 8 different locations, wherein the single glass pane (hereinafter referred to as the third glass pane, GP3) is facing the exterior of the building. The single glass pane is separated from the VIG by a peripheral spacer of 15mm and the internal space if filled with argon. The single glass pane has a solar control coating, on its surface facing the internal space of the double glazing. The VIG comprises a first glass pane, GP1 and a second glass pane, GP2. The second glass pane faces the internal space of the double glazing. The first glass pane has a low- emissivity coating on its surface facing the internal volume of the VIG.

Reference configuration: VIG comprising GP2 having a thickness of 6mm and GP1 having a thickness of 6mm;

Comparative configuration represented by the grey dots: VIG comprising GP2 having a thickness of 6mm and GP1 having a thickness of 4mm;

Configuration of the present invention, represented by the black squares: VIG comprising GP2 having a thickness of 4mm and GP1 having a thickness of 6mm.

[0032] A normalized performance indicator P has been calculated. It corresponds to ratio of the maximal thermal induced stress throughout winter and summer conditions at each location, for the studied configuration over the corresponding stress for the reference configuration. If P is equal to 1, the tested configuration does not provide any improvement. If P > 1, then the tested configuration demonstrates an increased thermal induced stress. If P < 1, then the tested configuration demonstrates a reduced thermal induced stress. The normalized performance indicator is represented on the Y axis of the graph below.

[0033] The ratio of absolute value of the temperature difference ( | AT | ) during summer over absolute value of the temperature difference ( | AT | ) during winter, has been represented on the X-axis of the graph below and is herein referred as "Temperature Ratio".

[0034] The chart demonstrates that the asymmetry of the VIG wherein the thicker glass pane faces the internal space, does not provide reduced thermal induced stress. Indeed, the normalized performance indicator, P, stays above 1 for all Temperature Ratios. In contrast, the chart demonstrates that the asymmetry of the VIG wherein the thinner glass pane faces the internal space of the multiple glazing, does provide reduced thermal induced stress and so even more when the Temperature Ratio increases.

[0035] Hence, it has been found that when the VIG is incorporated into a multiple glazing, the temperature of the internal space can be surprisingly high in summer. Therefore, in addition to the thermal induced stress that should be necessarily considered in winter, it is also required to consider the thermal induced stress in summer. The summer thermal induced stress can even become the most critical parameter to be considered for the design of the VIG. In such cases, the present invention teaches to design a multiple glazing wherein the VIG unit is asymmetric and orientated so that the thin glass pane faces the internal space of the multiple glazing.

[0036] Accordingly, and as illustrated in Figure 1, the present invention relates to a multiple glazing (10) extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Y. The multiple glazing comprise at least one vacuum insulating glazing unit (20), a third glass pane, GP3, and a peripheral spacer (6).

[0037] The VIG within the multiple glazing of the present invention, comprises: a. a first glass pane, GP1, having a thickness Zl, and having an inner pane face (11) and an outer pane face (12) and a second glass pane, GP2, having a thickness, Z2, and having an inner pane face (21) and an outer pane face (22). The thicknesses are measured in the direction normal to the plane, P; b. a set of discrete spacers (3) positioned between the first and second glass panes, maintaining a distance between the first and the second glass panes; c. a hermetically bonding seal (4) sealing the distance between the first and second glass panes over a perimeter thereof; d. an internal volume, V, defined by the first and second glass panes and the set of discrete spacers and closed by the hermetically bonding seal, under vacuum. By vacuum it is meant, a pressure of less than 0.1 mbar. The inner pane faces of the first and second glass panes of the VIG, face the internal volume, V.

[0038] The third glass pane, GP3, has an inner pane face (31) and an outer pane face (32). The peripheral spacer (6) is positioned between the outer pane face (22) of the second glass pane, GP2 and the inner pane face (31) of the third glass pane, GP3, over a perimeter thereof, maintaining a distance there between. The peripheral spacer, the outer pane face (22), and the inner pane face (31) define an internal space, Sp.

[0039] Within the present invention, the second glass pane, GP2, of the VIG is facing the internal space, Sp, of the multiple glazing.

[0040] The inner pane face (11) of the first glass pane, GP1, can typically be coated with a low- emissivity coating (5).

[0041] Within the present invention, the thickness ratio, Z1/Z2, of the thickness of the first glass pane, Zl, to the thickness of the second glass pane, Z2, is equal to or greater than 1.10 (Zl / Z2 > 1.10). In a preferred embodiment, the thickness ratio of the thickness of the first glass pane, Zl, to the thickness of the second glass pane, Z2, is equal to or greater than 1.20 (Z1/Z2 > 1.20); preferably equal to or greater than 1.30 (Z1/Z2 > 1.30), preferably equal to or greater than 1.50 (Z1/Z2 > 1.50), preferably equal to or greater than 1.55 (Z1/Z2 > 1.55), more preferably equal to or greater than 1.60 (Z1/Z2 > 1.60). In a preferred embodiment, the vacuum insulating assembly has a thickness ratio, Z1/Z2, of the thickness of the first glass pane, Zl, to the thickness of the second glass pane, Z2, lower than or equal to 6.00 (Z1/Z2 < 6.00), lower than or equal to 4.00 (Z1/Z2 < 4.00), lower than or equal to 2.50 (Z1/Z2 < 2.50). In a more preferred embodiment, the vacuum insulating assembly has a thickness ratio, Z1/Z2 comprised between 1.20 and 1.60 (1.20 < Z1/Z2 < 1.60), preferably between 1.30 and 1.60 (1.30 < Z1/Z2 < 1.60). It has been surprisingly found that the thickness ratio should be as high as possible to reduce the thermal induced stress during summer conditions but should not be too high to avoid deteriorating the thermal induced stress in winter conditions.

[0042] In a preferred embodiment, within the VIG encompassed into the multiple glazing of the present invention, the thickness of the second glass pane, Z2, is equal to or greater than 1 mm, (Z2 > 1 mm), preferably equal to or greater than 2 mm, (Z2 > 2 mm), preferably equal to or greater than 3 mm, (Z2 > 3 mm), preferably equal to or greater than 4 mm, (Z2 > 4 mm), more preferably equal to or greater than 6 mm, (Z2 > 6 mm). In a preferred embodiment of the present invention, the thickness of the second glass pane, Z2, is comprised between 1 mm and 8 mm (1 mm < Z2 < 8 mm), preferably between 2 mm and 6 mm (2 mm < Z2 < 6 mm).

[0043] In a preferred embodiment, within the VIG encompassed into the multiple glazing of the present invention, the thickness of the first glass pane, Zl, is equal to or greater than 2 mm, (Z1 > 2 mm), preferably equal to or greater than 3 mm, (Zl > 3 mm), preferably equal to or greater than 4 mm, (Zl > 4 mm), preferably equal to or greater than 6 mm, (Zl > 6 mm), preferably equal to or greater than 8 mm, (Zl > 8 mm), more preferably equal to or greater than 10 mm, (Zl > 10 mm). In a preferred embodiment of the present invention, the thickness of the first glass pane, Zl, is comprised between 2 mm and 10 mm (2 mm < Zl < 10 mm), preferably between 3 mm and 8 mm (3 mm < Zl < 8 mm).

[0044] In a preferred embodiment, within the VIG encompassed into the multiple glazing of the present invention, the thickness of the third glass pane, Z3, is typically equal to or greater than 2 mm (Z3 > 2 mm), preferably are equal to or greater to 3 mm, (Z3 > 3 mm), more preferably equal to or greater to 4 mm, (Z3 > 4 mm) more preferably equal to or greater to 6 mm, (Z3 > 6 mm). Typically, the thickness of the third glass pane, Z3, will be not more than 12 mm (Z3 < 12 mm), preferably not more than 10 mm (Z3 < 10 mm), more preferably not more than 8 mm (Z3 < 8mm). The thicknesses are measured in the direction normal to the plane, P. In a preferred embodiment, the thickness of the third glass pane, Z3, is comprised between 1 mm and 12 mm (1 mm < Z3 < 12 mm), preferably between 3 mm and 10 mm (3 mm < Z3 < 10 mm), more preferably between 4 mm and 8 mm (4 mm < Z3 < 8 mm). [0045] In a preferred embodiment of the present invention, the multiple glazing has a length, L, measured along the vertical axis, Y; equal to or greater than 500 mm, (L > 500 mm), equal to or greater than 800 mm (L > 800 mm), more preferably equal to or greater than 1200 mm, (L > 1200 mm). In a preferred embodiment of the present invention, the multiple glazing has a width, W, measured along the longitudinal axis, X; equal to or greater than 300 mm, (W > 300 mm), preferably equal to or greater than 400mm, (W > 400 mm) more preferably equal to or greater than 500mm, (W > 500 mm), more preferably equal to or greater than 750 mm, (W > 750 mm); more preferably equal to or greater than 1000 mm, (W > 1000 mm); even more preferably equal to or greater than 1000 mm, (W > 1000 mm).

[0046] In one embodiment of the present invention, the multiple glazing can comprise only VIG units so that above described single glass pane, GP3, is encompassed within a vacuum insulating unit comprising the single glass pane, GP3, and an additional glass pane, GP4, forming together a second VIG unit similar to the VIG described above. All technical features and preferred technical features described herein above and further in relating to the double glazing or multiple glazing comprising a single glass pane, can be applied respectively to multiple glazing configuration. Therefore, in this embodiment, the third glass pane, GP3, is further associated to a fourth glass , GP4, by a set of discrete spacers positioned between the third and the fourth glass panes, maintaining a distance between them; a hermetically bonding seal sealing the distance between them over a perimeter thereof; creating an internal volume, V, wherein there is a vacuum having a pressure of less than 0.1 mbar.

VACUUM INSULATING GLAZING

[0047] VIGs typically comprise a first glass pane and a second glass pane that are associated together by way of a set of discrete spacers that hold said panes a certain distance apart, typically in the range of between 50 pm and 1000 pm, preferably between 50 pm and 500 pm and more preferably between 50pm and 150pm. In general, in order to achieve a high-performance thermal insulation (Thermal transmittance, Ug, being Ug<1.2 W/m²K) the absolute pressure inside the glazing unit is typically 0.1 mbar or less and generally at least one of the two glass panes is covered with a low-emissivity layer. To obtain such a pressure inside the glazing unit, a hermetically bonding seal is placed on the periphery of the two glass panes and vacuum is generated inside the glazing unit by virtue of a pump. To prevent the glazing unit from caving in under atmospheric pressure (due to the pressure difference between the interior and exterior of the glazing unit), discrete spacers are placed between the two glass panes. Spacers

[0048] The discrete spacers (also referred to as "pillars") are positioned between the first and the second glass panes, maintaining a distance there between them and forming an array having a pitch, X, comprised between 10 mm and 100 mm (10 mm < X < 100 mm). By pitch, it is meant the interval between the discrete spacers. In a preferred embodiment, the pitch is comprised between 15 mm and 80 mm (15 mm < X < 80 mm), preferably between 15 mm and 50 mm (15 mm < X < 50 mm), preferably between 15 mm and 40 mm (25 mm < X < 40 mm), more preferably between 15 mm and 25 mm (15 mm < X < 25 mm), even more preferably is about 20 mm. The array within the present invention is typically a regular array based on an equilateral triangular, square or hexagonal scheme, preferably based on a square scheme. The discrete spacers can have different shapes, such as cylindrical, spherical, filiform, hourglass, C-shaped, cruciform, prismatic shape... It is preferred to use small pillars, i.e. pillars having in general a contact surface with the glass pane, defined by its external circumference, equal to or lower than 5 mm², preferably equal to or lower than 3 mm², more preferably equal to or lower than 1 mm² . These values may offer a good mechanical resistance whilst being aesthetically discrete.

[0049] Typical discrete spacers are made of a material with durable resistance to the pressure and high-temperature faced during the production process of the VIG and hardly emitting any gas after the glazing is manufactured. Such a material is preferably a hard material such as metal material, quartz glass or a ceramic material, in particular a metal material such as iron, tungsten, nickel, chrome, titanium, molybdenum, carbon steel, chrome steel, nickel steel, stainless steel, nickel-chromium steel, manganese steel, chromium-manganese steel, chromium-molybdenum steel, silicon steel, nichrome, duralumin or the like. Another such material can be a ceramic material such as corundum, alumina, mullite, magnesia, yttria, aluminum nitride, silicon nitride or the like. However, if such material provides higher mechanical resistance, they provide rather poor performance in thermal conductivity (high thermal conductivity). Therefore, preferred discrete spacers for the VIG element of the multiple glazing of the present invention are made of material of lower conductivity such as resins, preferably made of polyimide resin. In this case, it is possible to minimize the thermal conductivity of the spacer and heat is hardly transferred via the discrete spacers in contact with the first and the second glass panes.

The hermetically Bonding Seal

[0050] The internal volume of the VIG is closed with a hermetically bonding seal placed on the periphery of the glass panes around said internal space. The hermetically bonding seal is impermeable to air or any other gas present in the atmosphere. Various hermetically bonding seal technologies exist. A first type of seal (the most widespread) is a seal based on a solder glass for which the melting point is lower than that of the glass panes of the glazing unit. Typically lower than 500°C, preferably lower than 450°C, more preferably lower than 400°C. Examples are low melting point glass frits such as bismuth based glass frits, lead based glass frits, vanadium based glass frits and mixtures thereof. A second type of seal comprises a metal seal, for example a metal strip of a small thickness (<500 pm) soldered to the periphery of the glazing unit by means of a tie underlayer covered at least partially with a layer of a solderable material such as a soft tin-alloy solder.

Internal volume

[0051] A vacuum of absolute pressure less than 0.1 mbar, preferably less than O.Olmbar is created, within the internal volume, V, defined by the first and second glass panes and the set of discrete spacers and closed by the hermetically bonding seal. A getter can be used to maintain for the duration a given vacuum level in a vacuum-insulating glazing unit. Generally, such a getter consists of alloys of zirconium, vanadium, iron, cobalt, aluminum, etc., and is deposited in the form of a thin layer (a few microns in thickness) or in the form of a tablet placed between the glass panes.

MULTIPLE GLAZING

[0052] Within the multiple glazing of the present invention, the peripheral spacer maintains a certain distance between the third glass pane and the second glass pane of the VIG . The peripheral spacer extends along the edges of the glazing and is positioned between the outer pane face of the second glass pane GP2 and the inner pane face of the third glass pane GP3 over a perimeter thereof, and maintains a distance there between. The peripheral spacer and said outer pane faces define an internal space, Sp.

[0053] Typically said spacer comprises a desiccant and has typically a thickness comprised between 4 mm to 32 mm, preferably 4 to 22 mm preferably 4 to 16 mm, more preferably 6 to 12 mm. In general, the internal space Sp is filled with air and/or inert gas selected from dry air, argon, xenon, krypton, or mixtures thereof, preferably from argon or a mixture of air and argon. The nature of gas and the distance between GP2 an GP3 are selected to provide appropriate reduction of heat transfer and/or sound transmission. [0054] In its role of maintaining an internal space Sp, the peripheral spacer must of course provide proper tightness properties. It is critical for a peripheral spacer to prevent the release of inert gas from the internal space Sp and/or also to prevent the entry of water vapor. The peripheral spacer is typically an object of elongated shape and constant cross section. The peripheral spacer may be a solid or hollow element.

[0055] Examples of peripheral spacer include metal spacer, ceramic spacer, glass spacer, polymeric spacer, and combinations or composites thereof. Examples of polymeric peripheral spacer include polyisobutylene-butyl mixture, silicone rubber foam, polypropylene, PVC, styrene acrylo nitrile or biopolymers, and mixtures or combinations of these. Further examples of polymeric peripheral spacer include transparent rigid materials such as polymethylmethacrylate (PMMA), polycarbonate, polystyrene, polyamide and/or polyester, which may provide transparency along the edges. Metal, ceramic or glass peripheral spacers are also suitable materials. Examples of metal include galvanized steel, stainless steel, aluminum alloy. Examples of composite peripheral spacer include polypropylene/stainless steel.

[0056] In a preferred embodiment of the present invention, the peripheral spacer within the multiple glazing is a warm edge peripheral spacer that has a better thermal performance than standard aluminum spacer bar. The definition of a warm edge peripheral spacer is a thermally improved spacer having a thermal conductance value of < 0.007 W/K calculated according to EN10077-1 annex E.

[0057] The peripheral spacer may have adhesive properties, such that it adheres directly to the glass pane faces in contact with it. For instance, polyisobutylene-butyl mixture (also known as thermoplastic spacer or TPS), in extruded form, have intrinsic tightness and adhesion properties. They offer the advantage of allowing good adhesion to the glass panes, and to compensate for irregularities in the flatness of these panes, thus ensuring a good seal. They also offer the advantage to adapt to all possible shapes.

[0058] In other instances where the peripheral spacer does not have adhesive properties such as for silicone rubber foam, a first peripheral seal is required between the third glass pane and the peripheral spacer and between the second glass pane and the peripheral spacer. The adhesive provides the tightness and contributes to the mechanical strength of the construction. Examples of first peripheral seal materials include polyisobutylene, acrylic resin, epoxy resin, polyurethane resin, and mixtures or combinations thereof. Preferred first peripheral seal materials are polyisobutylene and/or acrylic resin. [0059] The peripheral spacer may typically be provided with a desiccative material. When the peripheral spacer is a hollow frame, the desiccative material will at least partially fill the hollow space. Examples of desiccative materials capable of filling the hollow space are silica gels, zeolite and other molecular sieves. When the peripheral spacer is a solid polymeric frame, the desiccative material may be incorporated into the polymer matrix. An example of such a desiccative polymer is a polymer comprising an integrated molecular sieve.

[0060] If the first peripheral seal is not enough to provide the required gas tightness and/or mechanical strength, a second peripheral seal may be present between the single glass pane and the VIG and cover the peripheral spacer and first peripheral seal towards the exterior. This second peripheral seal may serve for the air tightness of the internal space and for mechanical support of the glazing. The second peripheral seal typically has a very good mechanical strength, in addition to adhesion of glass and possibly water vapor and gas tightness. Examples of second peripheral seal materials include polyisobutylene, silicone, polysulfide, polyurethane or mixtures or combinations thereof. Preferred second peripheral seal materials are silicone, polysulfide and/or polyurethane.

PANES AND SHEETS

[0061] The VIG glass panes, GP1 and GP2 and the third glass pane, GP3, can be chosen among float clear, extra-clear or colored glass. Typically, the glass panes are soda-lime-silica glass, aluminosilicate glass or borosilicate glass; preferably soda-lime-silica glass. Textured, structured, printed glass are suitable. The glass panes can optionally be edge-ground for safety.

[0062] The glass panes GP1 and/or GP2 of the VIG and/or the third glass pane, GP3 of the multiple glazing can be laminated to at least a glass sheet by a polymer interlayer to form a laminated glass pane. In a preferred embodiment of the present invention, at least one of the inner pane face of the third glass pane (31), the outer pane face of the third glass pane (32), the outer pane face of the second glass pane (22) and/or the outer pane face of the first glass pane (12) is laminated to at least a glass sheet (5) by a polymer interlayer (6) to form a laminated glass pane.

[0063] In a preferred embodiment, the outer pane face of the glass panes GP1 and/or the third glass pane, GP3 of the multiple glazing assembly can be laminated to at least a glass sheet by a polymer interlayer to form a laminated glass pane. It has been surprisingly found that laminating the first glass pane, GP1, of the VIG can contribute further to the improved resistance to the thermal induced stress. [0064] Preferably, the glass sheet for lamination has a thickness Zs measured in the direction normal to the plane, P; equal to or greater than 1mm (Zs > 1mm), preferably equal to or greater than 2mm (Zs > 2mm), preferably equal to or greater than 3mm (Zs > 3mm), preferably equal to or greater than 4mm (Zs > 4mm). In a preferred embodiment, the thickness of the glass sheet, Zs, is comprised between 1mm and 8mm (1mm < Zs < 8mm), preferably between 1mm and 6mm (1mm < Zs < 6mm), preferably between 2mm and 4mm (2mm < Zs < 4mm), more preferably is 4mm (Zs = 4mm). It is further preferred that the thickness of the first, second and/or third glass pane and the thickness of the glass sheet are different (Zl, Z2 and/or Z3 * Zs).

[0065] The polymer interlayer comprises typically a material selected from the group consisting of ethylene vinyl acetate (EVA), polyisobutylene (PIB), polyvinyl butyral (PVB), autoclave-free polyvinyl butyral (Autoclave-free PVB), polyurethane (PU), polyvinyl chlorides (PVC), polyesters, copolyesters, polyacetals, cyclo olefin polymers (COP), ionomers and/or an ultraviolet activated adhesive, and others known in the art of manufacturing glass laminates. Reinforced acoustic insulation can be provided with a polymer interlayer with specific acoustic performance, such as specific PVBs (Saflex® acoustic PVB interlayer from Eastman or Trosifol® acoustic PVB interlayer from Kuraray). Preferably, the polymer interlayer is selected from the group consisting of ethylene vinyl acetate (EVA), Cyclo olefin polymers (COP), autoclave-free polyvinyl butyral (Autoclave-free PVB), polyurethane (PU), ionomers like SentryGlas™ and combinations thereof, more preferably from EVA and/or autoclave- free PVB.

[0066] A preferred embodiment is a multiple glazing wherein the third glass pane has a thickness, Z3, measured in the direction normal to the plane, P; comprised between 4mm and 8mm (4mm < Z3 < 8mm, preferably between 4mm and 6mm (4mm < Z3 < 6mm), and the third glass pane is laminated to a glass sheet having a thickness Zs comprised between 4mm and 8mm (4mm < Zs < 8mm), preferably between 4mm and 6mm (4mm < Zs < 6mm), preferably by an acoustic PVB polymer interlayer. It is even further preferred that the thickness of the third glass pane and the thickness of the glass sheet(s) are different (Z3 * Zs).

[0067] Typically, the glass panes are annealed glass panes. However, to provide a multiple glazing with higher mechanical performances and/or to improve further the safety, it can be contemplated to use prestressed glass for one or more glass pane(s) of the multiple glazing. In one preferred embodiment, the first glass pane and/or the third glass pane is a prestressed glass. In another preferred embodiment, the second glass pane is a prestressed glass. By prestressed glass, it is meant herein a heat strengthened glass, a thermally toughened safety glass, or a chemically strengthened glass.

[0068] Heat strengthened glass and thermally toughened safety glass are heat treated using a method of controlled heating and cooling which places the glass surface(s) in compression and the other core under tension. The heat treatment method delivers a glass with a bending strength greater than annealed glass but less than thermally toughened safety glass. The thermally toughened safety glass when impacted, breaks into small granular particles instead of splintering into jagged shards. The granular particles are less likely to injure occupants or damage objects.

[0069] The chemical strengthening of a glass article is a heat induced ion-exchange, involving replacement of smaller alkali sodium ions in the surface layer of glass by larger ions, for example alkali potassium ions. Increased surface compression stress occurs in the glass as the larger ions "wedge" into the small sites formerly occupied by the sodium ions. Such a chemical treatment is generally carried out by immerging the glass in an ion-exchange molten bath containing one or more molten salt(s) of the larger ions, with a precise control of temperature and time. Aluminosilicate-type glass compositions, such as for example those from the product range DragonTrail® from Asahi Glass Co. or those from the product range Gorilla® from Corning Inc., are known to be very efficient for chemical tempering.

[0070] Preferably, the composition of the glass pane comprises the following components in weight percentage, expressed with respect to the total weight of glass (Comp. A). More preferably, the glass composition (Comp. B) is a soda-lime-silicate-type glass with a base glass matrix of the composition comprising the following components in weight percentage, expressed with respect to the total weight of glass.

[0071] Other preferred glass comprises the following components in weight percentage, expressed with respect to the total weight of glass:

[0072] In a preferred embodiment, within the VIG, the first glass pane has a coefficient of thermal expansion, CETI, and the second glass pane has a coefficient of thermal expansion, CET2, whereby the absolute difference between CETI and CET2 is equal to or at most 0.40 10-6/°C ( | CET1-CET21 <0.40 10-6/°C); preferably is at most 0.30 10-6/°C ( | CET1-CET21 <0.30 10-6/°C), more preferably equal to or at most 0.20 10-6/°C ( | CET1-CET21 <0.20 10-6/°C). Ideally, the first and second glass panes have the same coefficient of thermal expansion ( | CTE1-CTE21 = 0 /°C). The "coefficient of thermal expansion" (CTE) is a measure of how the size of an object changes with a change in temperature. Specifically, it measures the fractional change in volume of the glass pane per degree change in temperature at a constant pressure.

[0073] In some embodiments of the present invention, functional coatings such as low emissivity coatings, solar control coatings (heat ray reflection coatings), anti-reflective coatings, anti-fog coatings, preferably a heat ray reflection coating or a low emissivity coating, can be provided on at least one of the glass panes of the multiple glazing unit. Preferably, the inner pane face of the first and/or second glass pane(s); the inner pane face and/or outer pane face of the third glass pane; and/or the outer sheet face of the glass sheet - if one of the glass panes of the multiple glazing has been further laminated to a glass sheet; is provided with at least a heat ray reflection coating or a low-emissivity coating.

[0074] In one embodiment, the outer pane face of the first glass pane (12) can be provided with at least one spall shield polymer film, preferably with a polyester spall shield film. [0075] The multiple glazing of the present invention is typically used to close an opening within a partition in buildings, in transport such as cars, train, boats,... and in appliances such as fridges, cold cabinets,.... The partition typically separates the exterior environment from an interior space such as the interior of a building or a car. In the present invention, the multiple glazing can be used such that the single glass pane faces the exterior environment or the interior space, preferable faces the exterior environment.

[0076] The person skilled in the art realizes that the present invention is by no means limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. It is further noted that the invention relates to all possible combinations of features, and preferred features, described herein and recited in the claims. It is well understood by persons skilled in the art that, as used herein the terms "a", "an" or "the" means at least "one" and should not be limited to "only one" unless explicitly stated otherwise. Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner.

Claims

1. A multiple glazing (10) extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Y comprising at least : a. a vacuum insulating glazing unit comprising: i. a first glass pane, GP1, having a thickness Zl, and having an inner pane face (11) and an outer pane face (12) and a second glass pane, GP2, having a thickness, Z2, and having an inner pane face (21) and an outer pane face (22); wherein the thicknesses are measured in the direction normal to the plane, P; ii. a set of discrete spacers (3) positioned between the first and the second glass panes, maintaining a distance between the first and the second glass panes; ill. a hermetically bonding seal (4) sealing the distance between the first and the second glass panes over a perimeter thereof; iv. an internal volume, V, defined by the first and the second glass panes and the set of discrete spacers and closed by the hermetically bonding seal and wherein there is a vacuum having a pressure of less than 0.1 mbar; and wherein the inner pane faces face the internal volume, V; b. a third glass pane, GP3, having an inner pane face (31) and an outer pane face (32); and c. a peripheral spacer (6) positioned between the outer pane face (22) of the second glass pane, GP2, and the inner pane face (31) of the third glass pane, GP3, over a perimeter thereof, that maintains a distance there between; and wherein the peripheral spacer (6), the outer pane face (22), and the inner pane face (31) define an internal space, Sp; wherein a thickness ratio, Z1/Z2, of the thickness of the first glass pane, Zl, to the thickness of the second glass pane, Z2, is equal to or greater than 1.10 (Zl / Z2 > 1.10), and wherein the second glass pane, GP2, is facing the internal space, Sp.

2. A multiple glazing according to claim 1 wherein the vacuum insulating glazing unit has a thickness ratio, Z1/Z2, of the thickness of the first glass pane, Zl, to the thickness of the second glass pane, Z2, equal to or greater than 1.20 (Z1/Z2 > 1.20); preferably equal to or greater than 1.30 (Z1/Z2 > 1.30), preferably equal to or greater than 1.50 (Z1/Z2 > 1.50), preferably equal to or greater than 1.55 (Z1/Z2 > 1.55), more preferably equal to or greater than 1.60 (Z1/Z2 > 1.60).

3. A multiple glazing according to any one of the preceding claims wherein the vacuum insulating glazing unit has a thickness ratio, Z1/Z2, of the thickness of the first glass pane, Zl, to the thickness of the second glass pane, Z2, lower than or equal to 6.00 (Z1/Z2 < 6.00), lower than or equal to 4.00 (Z1/Z2 < 4.00), lower than or equal to 2.50 (Z1/Z2 < 2.50).

4. A multiple glazing according to any one of the preceding claims wherein the vacuum insulating glazing unit has a thickness ratio, Z1/Z2 comprised between 1.20 and 1.60 (1.20 < Z1/Z2 < 1.60), preferably between 1.30 and 1.60 (1.30 < Z1/Z2 < 1.60).

5. A multiple glazing according to any one of the preceding claims, wherein the thickness of the second glass pane, Z2, is comprised between 1 mm and 8 mm (1 mm < Z2 < 8 mm), preferably between 2 mm and 6 mm (2 mm < Z2 <6 mm).

6. A multiple glazing according to any one of the preceding claims, wherein the thickness of the first glass pane, Zl, is comprised between 2 mm and 10 mm (2 mm < Zl < 10 mm), preferably between 3 mm and 8 mm (3 mm < Zl < 8 mm).

7. A multiple glazing according to any one of the preceding claims wherein at least one of the inner pane face of the third glass pane, the outer pane face of the third glass pane, the outer pane face of the second glass pane and/or the outer pane face of the first glass pane is laminated to at least a glass sheet by a polymer interlayer to form a laminated glass pane.

8. A multiple glazing according to claim 7 wherein the outer pane face of the first glass pane is laminated to at least a glass sheet by a polymer interlayer to form a laminated glass pane.

9. A multiple glazing according to any one of the preceding claims 7 to 8, wherein the glass sheet has a thickness Zs measured in the direction normal to the plane, P; comprised between 1mm and 8mm (1mm < Zs < 8mm), preferably between 1mm and 6mm (1mm < Zs < 6mm), more preferably 2mm and 4mm (2mm < Zs < 4mm), preferably equals 4mm (Zs = 4 mm).

10. A multiple glazing according to any one of the preceding claims 7 to 9, wherein third glass pane has a thickness, Z3, measured in the direction normal to the plane, P; comprised between 4mm and 8mm (4mm < Z3 < 8mm, preferably between 4mm and 6mm (4mm < Z3 < 6mm), and wherein the third glass pane is laminated to a glass sheet having a thickness Zs comprised between 4mm and 8mm (4mm < Zs < 8mm), preferably between 4mm and 6mm (4mm < Zs < 6mm), preferably by an acoustic PVB polymer interlayer.

11. A multiple glazing according to any one of the preceding claims, comprising further at least a functional coating, preferably a heat ray reflection coating or a low-emissivity coating, on at least one of the glass panes face.

12. A multiple glazing according to any one of the preceding claims, wherein the set of discrete spacers forms an array having a pitch comprised between 15 mm and 80 mm, preferably between 15 mm and 50 mm and more preferably between 15 and 40 mm, more preferably between 15mm and 25mm and even more preferably is about 20mm.

13. A multiple glazing according to any of the preceding claims, wherein the first glass pane has a coefficient of linear thermal expansion, CTE1, and the second glass pane has a coefficient of linear thermal expansion, CTE2, and wherein the absolute difference between CTE1 and CTE2 is at most 1.2 10’7°C ( | CTE1-CTE21 < 1.2 10’7°C), preferably is at most 0.8 10’7°C ( | CTE1-CTE21 < 0.8 10’7°C), more preferably at most 0.4 10'7°C ( | CTE1-CTE21 < 0.4 10'7°C) , more preferably at most 0.2 10'7°C ( | CTE1- CTE21 < 0.2 10'7°C) even more preferably equals 0 ( | CTE1-CTE21 = 0 /°C).

14. A multiple glazing according to any of the preceding claims, wherein one glass pane of the multiple glazing is prestressed glass, preferably the first glass pane and/or the third glass pane is prestressed glass or preferably the second glass pane is prestressed glass.