EP3698002B1

EP3698002B1 - Gas-filled insulating glazing unit

Info

Publication number: EP3698002B1
Application number: EP18795945.7A
Authority: EP
Inventors: Olivier Bouesnard; Pierre Schneider; Marco ZACCARIA
Original assignee: AGC Glass Europe SA
Current assignee: AGC Glass Europe SA
Priority date: 2017-10-20
Filing date: 2018-10-15
Publication date: 2022-06-01
Anticipated expiration: 2038-10-15
Also published as: EP3698002A1; WO2019076804A1; PL3698002T3

Description

Field of the invention

The invention relates to an insulating glazing unit. More particularly, it relates to an insulating glazing unit (IGU) comprising at least a first and second glass panes and an insulating gas that is filling the interspace between the first and the second glass pane. The IGU of the invention is suitable for different interior and exterior applications such as windows, doors, partition walls, curtain walls, roofs and the like. It can also be used in a temperature conditioned product presentation appliance such as a refrigerated cabinet.

Description of prior art

Gas-filled insulating glazing units comprising at least two glass panes are widely used for different applications requiring thermal insulation.
Generally, a first glass pane is placed opposite to a second glass pane and an edge spacer assembly is placed between the glass panes to hold them at a certain distance from each other and to sealingly couple the first and the second glass panes around their perimeter. The edge spacer assembly typically comprises a spacer element made out of metal or a composite material. The edge spacer assembly further comprises sealing elements sealingly coupling the spacer element and the glass panes. In this way, a hermetically sealed interspace is formed between the first and the second glass panes that is filled with an insulating gas so as to reduce heat conductivity. The insulating gas is generally dry air or an inert gas such as argon, krypton or xenon or any mixtures of these. Such a gas-filled IGU with an edge spacer assembly is for example disclosed by Buddenberg et al. in Glass Struct. Eng. (2016) pages 301-313.
There is nowadays a strong demand for glazing units having on one hand the required level of thermal insulation and on the other hand an increased transparent area. An approach to increase the transparent area of the IGU is to remove frame elements on some or all the IGU edges in combination with an edge spacer assembly that is transparent along said edges. It requires to replace standard materials used so far as spacer element and sealing elements by elements that are transparent, but that are also still able to fulfill the requirements of standard ones, namely:

to have a tightly sealed interspace,
to stiffen the glazing unit in its periphery to withstand short term stresses like wind load or openings and closings in the absence of frame usually ensuring that function,
to provide the needed flexibility to allow glass edges deformation and release the long term stresses due to temperature differences between the glass panes, known as climatic loads, e.g. due to seasonable temperature variations between winter and summer or temperature variations between day and night.

Indeed, the long term stresses or climatic load acts on the glass panes due to changes in the climatic conditions surrounding the glass panes. During the production process of IGU's, under given factory temperature and pressure conditions, the interspace is filled with the insulating gas and the interspace is further kept hermetically sealed. If the gas temperature or the atmospheric pressure changes, a pressure difference between the interspace and the environment occurs. The pressure balance can be restored by an increase or decrease of the volume in the interspace. The expanding or contracting gas volume of the interspace causes deformation of the glass panes, which in turn results in mechanical stress. The deformations resulting from these climatic loads are discussed for example by Buddenberg et al. in the reference mentioned above.
In addition to these long term periodic stresses caused by the climatic loads, the IGU's also suffer from short term mechanical stresses. These short term mechanical stresses are caused for example by blowing wind or openings and closings of a door or window, which result in a pressure and depression exercised on the insulating glazing unit. As a result for instance of a wind pressure, the glass panes of the insulating glazing unit will bend. Depending on the bending and resulting stress level, cracks and/or breakage might occur in the glass panes. The bending can also disturb the vision through the glazing units.
Technical solutions to increase the transparent area of an IGU by the use of a transparent edge spacer assembly are for instance disclosed in WO2016091954 , WO2010119067 , DE9411674 , WO2017036834 or WO2017036832 . It is disclosed multiple glazing comprising edge spacer assemblies comprising a transparent spacer that may be in glass, toughened glass or in organic material and transparent adhesives or seals placed between each of the glass panes and the spacer, i.e. a pile of transparent adhesive or seal/transparent spacer/ transparent adhesive or seal is present between two glass panes. However, the presence of seals between each of the glass panes and the spacer limits the stiffening effect of the spacer.
In US20150151511 , a multiple glazing is disclosed that comprises at least two transparent glass panes that are joined in the edge area by a transparent mass or one that becomes transparent after hardening. The junction between the glass panes is ensured by the sole transparent mass, which cannot alone bring at the same time a stiffening and a stress releasing effect.

Objectives of the invention

It is therefore an objective of the invention to remedy the drawbacks of the aforementioned prior art.
It is an object of the present invention to provide a gas-filled insulating glazing unit comprising an edge spacer assembly that has at least one transparent side, which:

Provides at the same time a stiffening and a stress releasing effect
Allows the use of a large variety of glass panes in addition to thermally treated or chemically tempered glass panes
Allows the use of complex shapes stiffening parts

It is another object of the invention to provide a glazed assembly comprising one or more gas-filled insulating glazing units comprising said edge spacer assembly that has at least one transparent side.
It is a particular object of the invention to provide a frameless glazed assembly, having sufficient stiffness to avoid the use of some frame elements and stress releasing performances to withstand climatic loads.

Description of the invention

To this end, it is an object of the present invention to provide a gas-filled insulating glazing unit comprising:

a first and a second glass panes,
an edge spacer assembly extending between the first and second glass panes along their edges for holding them at a certain distance from each other and for sealingly coupling them so as to form a hermetically sealed interspace between them,
an insulating gas filling said interspace,

at least one transparent stiffening part comprising a transparent rigid material having a Young's modulus of at least 0.5 GPa,
one single transparent sealing part comprising a transparent viscoelastic polymer having a Young's modulus lower than 0.5 GPa,

The invention is not limited to the number of glass panes the IGU comprises, typically the IGU's comprise two glass panes, commonly known as double glazing or three glass panes, commonly known as triple glazing. The IGU's according to the invention are not limited to any specific glass panes. For instance, the glass panes can have a square, a rectangular, a circular, a triangular shape or any other shape, they may be flat or curved. The glass panes of the IGU's are not limited to any specific thickness and the different glass panes of the IGU's can have the same or different thicknesses, respectively known as symmetric and asymmetric IGU's. The thickness may typically vary from 0.5 mm to 25 mm. Similarly, the glass panes of the IGU's can have the same or different sizes like in stepped IGU's.
The type of glass panes is not particularly limited and maybe float glass panes or alternatively cast or drawn glass panes.
The glass panes according to the invention are made of glass whose matrix composition may belong to different categories. The glass may be a soda-lime-silicate glass, an alumino-silicate glass, an alkali-free glass, a boro-silicate glass and the like. It may be a clear, extra-clear/low-iron or colored glass sheet. Preferably, the glass panes of the invention are made of a soda-lime glass or an alumino-silicate glass. Non-limiting examples of glass panes are Planibel^® Clear, Linea Azzura^®, Dragontrail^®, Tirex^®, Falcon^®, Clearvision^®, Clearlite^®.
The glass panes can be chosen among all glass technologies, among them: float clear, extra-clear or colored glass, (partially) acid etched or (partially) sand blasted glass and combinations thereof.
The glass panes can be at least partially coated. By partially coated is meant that at least a part of their surface can be coated with a low-emissivity or a solar control coating or enamelled or combinations thereof.
Thermally treated or chemically tempered glass panes can be used. The thermally treated glass pane can be treated by any thermal treatment known by the skilled person such as heat strengthening (according to EN 1863-1:2011), thermal toughening (according to EN 12150-2:2015) or thermal toughening and heat soaking (according to EN 14179-2:2005). The glass pane thermally treated according to these standards is suitable as safety glass. Chemical tempering is particularly suited for thin glass panes.
Laminated glass panes may also be used, they consist of two or more glass panes assembled by a polymeric film, such as polyvinylbutyral (PVB), ethylenevinylacetate (EVA), thermoplastic polyurethanes (TPU) or ionoplast interlayer such as SentryGlas^®. In case of breakage, glass pieces remain attached to the polymeric film, avoiding people injuries, and maintaining the separation active.
A gas-filled insulating glazing unit according to the invention comprises at least a first glass pane, a second glass pane and an edge spacer assembly configured for coupling the first and the second glass panes, so as to form a hermetically sealed interspace between them. An insulating gas, is filling this interspace. Such a gas is generally chosen amongst air, argon, xenon, krypton, or any of their mixtures.
The edge spacer assembly according to the invention has at least one transparent side along one of the glass panes edges. Depending on the final glazed assembly in which the IGU will be inserted, more than one side can be transparent. The choice may be mainly directed by aesthetic and visual aspects.
The term "transparent" denotes a property illustrating the percentage T_L (light transmission) of visible light transmitted through a material in the visible spectrum of at least 1%. Preferably, transparent relates to a T_L property of at least 10%. Ideally, transparent denotes a T_L of at least 50%.
The at least one transparent side of the edge spacer assembly comprises at least two piled and connected transparent parts. By connected is meant linked together in a tight or sealed way. The connection is tight hence participating to the interspace tightness. These parts are further connected to the first and second glass panes through the top (S1) and bottom (S2) surfaces of the piled parts. Indeed, by piling at least two parts, a top and a bottom surfaces are naturally formed. In this way, the parts are not only connected between them, but the outer parts are also connected to the glass panes ensuring the tightness of the interspace. In some embodiments, said piled parts have a contact surface with the neighbouring part(s) that is substantially parallel to the glass panes.
In addition, at least one of the top (S1) or bottom (S2) surface belongs to a transparent stiffening part and is rigidly connected to the first or the second glass pane. By rigidly connected is meant that the assembly of the glass pane and the stiffening part has an overall Young's modulus of at least 0.5 GPa. We mean that the stress-strain curve of the assembly exhibits a slope of at least 0.5 GPa. In this case, the connection does not reduce the stiffening effect of the stiffening part.
The at least one transparent side of the edge spacer assembly according to the invention is characterized in that from the piled and connected transparent parts, there is at least one transparent stiffening part comprising a transparent rigid material, and one single transparent sealing part comprising a transparent viscoelastic polymer. Hence, the transparent side of the edge spacer assembly according to the invention comprises at least two transparent parts comprising a different material, a rigid material and a viscoelastic polymer.
The transparent stiffening part comprises a rigid material having a Young's modulus of at least 0.5 GPa, preferably at least 0.8 GPa or more preferably at least 1.0 GPa. The Young's modulus is a well-known quantity that can be measured according to methods known by the skilled person such as for instance according to ASTM D 638 and D 618 (Procedure A or B) in the case of polymers.
In some embodiments, the density of the transparent rigid material is additionally equal or larger than 0.5 g/cm³, preferably equal or larger than 0.8 g/cm3, more preferably equal or larger than 1.0 g/cm³.
Transparent rigid materials suitable for the present invention are organic or inorganic materials. Examples of suitable organic materials are rigid polymers and examples of suitable inorganic materials are glasses. Composites of such organic and inorganic materials are also suitable. Some examples of glass are soda-lime glass, alumino-silicate glass, boro-silicate glass. Transparent rigid materials are preferably transparent polymers, more preferably transparent polymers selected from a polymethyl methacrylate (PMMA), a polycarbonate (PC), a polystyrene (PS), a polyvinyl chloride (PVC), a polyamide (PA), a polyetherimide (PEI), a polyethylene terephthalate (PET), a polyurethane, an acrylonitrile butadiene styrene copolymer (ABS), a styrene acrylonitrile copolymer (SAN), a styrene methyl methacrylate copolymer (SMMA) and any mixtures of these; or a crosslinked resin. Polymers advantageously limit the thermal bridges between the glass pane in contact with the exterior atmosphere and the one in contact with the interior atmosphere of a building.
Crosslinked or cured resins are known to the skilled person and are three dimensional polymer networks obtained by the crosslinking/curing of low molecular weight species either by reaction with a curing agent also known as crosslinker or upon exposure to UV radiations (UV) or electron beam (EB). Examples of resins able to be crosslinked are epoxy resins, polyurethane resins, UV or EB curable resins. In the present invention, the precursors of the crosslinked resin may be transparent or not provided that the crosslinked resin is transparent.
Preferably, the transparent rigid material is chosen from a PMMA, a PC, a PS, a PVC or a mixture of any of these polymers or a crosslinked resin. More preferably, the transparent rigid material is chosen from a PMMA, a PC or a combination of these polymers.
Remark that some polymer mixtures, copolymers and some semicrystalline polymers can be opaque and non-transparent due to a dispersed phase or due to the presence of crystallites. Hence it is possible that not all compositions of the listed polymers mentioned above are transparent. The person skilled in the art is capable to identify what composition is transparent and hence identify if a given polymer falls within the claimed transparent polymers.
From the piled and connected parts, there is also one single, i.e. only one, transparent sealing part. This part comprises a viscoelastic polymer. Viscoelastic has here its general meaning, i.e. the ability of exhibiting both viscous and elastic characteristics when undergoing deformation. The current invention makes use of these viscoelastic properties to develop a transparent side of the edge spacer assembly that at the same time is stiff to resist to for example short term loads such as wind (elastic response) and at the same time is sufficiently deformable for example at higher temperatures or longer time scale to deal with stress resulting from climatic loads generally occurring over a longer time scale (viscous response).
The transparent viscoelastic polymers of the invention have a Young's modulus lower than 0.5 GPa. Preferred viscoelastic polymers according to the invention have additionally a loss coefficient of at least 0.1, preferably at least 0.3, more preferably at least 0.5. The loss coefficient has here its general meaning, it is a dimensionless quantity defining the degree to which a material dissipates vibrational energy and is measured by known dynamic mechanical analysis such as described in ASTM D 4065 and D 618 (Procedure A or B).
Non exhaustive examples of transparent viscoelastic polymers suitable for the present invention are polyurethanes, polyethylenes, PVB, ethylene vinyl acetate copolymer (EVA), neoprene, isoprene, polyisobutene, acrylics.
Some of these viscoelastic polymers such as polyisobutene have an intrinsic adhesive property and will connect to the neighbouring parts or to the glass pane by themselves. Others such as some members of the family of acrylics are applied uncured and have intrinsic adhesive property once cured. Yet others will be used in the form of a double-sided adhesive tape in which the core of the tape is made of the viscoelastic polymer such as an acrylic polymer, a polyurethane, a polyethylene that can be in the form of a foam. Preferably, the transparent viscoelatic polymers will be used in the form of a double-sided adhesive tape in which the core of the tape is made of an acrylic polymer or an acrylic polymer foam.
Note that some big classes of polymers such as acrylics and polyurethanes for instance may appear both as rigid polymers and as viscoelastic polymers. It is known to the skilled person that the large variety of monomers available to prepare them allows for multiple combinations leading to polymers that can either belong to the rigid polymers or to the viscoelastic polymers depending on the choice and relative amounts of monomers.
It is advantageous in the present invention to use a rigid material and a viscoelastic polymer that are free of volatile organic materials (VOC) so as to avoid a possible fogging effect in the interspace. By free of VOC is meant that the materials comprise less than 0.1wt% of VOC, they preferably comprise less than 1000 ppm VOC.
Without wishing to be bound by any theory, it is believed in the present invention that the combination of at least one first rigid part that is rigidly connected on one side to one of the glass panes with the second part comprising a viscoelastic polymer allows having a transparent side of the edge spacer assembly that at the same time is stiffening the IGU edge and is not blocking the glass edges displacement.
Indeed, the transparent stiffening part is stiffening the IGU edge to improve the resistance to short term stresses (as defined above in the description of prior art) such as a pressure and/or a depression of the wind. The stiffening effect is maximum when the stiffening part, is rigidly connected to the glass panes. A rigid connection allows a stiffness increase that is higher than the case where the stiffening part is flexibly connected to a glass pane. However, if the IGU edges are too stiff, the mechanical stresses induced by the glass panes deformation resulting from the climatic load will be concentrated along the edges of the glass panes. If the level of stress becomes too high, cracks and/or breakage may occur. The presence of the viscoelastic polymer allows some deformation, depending on the temperature and the speed of the load application. Hence, the viscoelastic polymer acts as a stress release component for releasing stress resulting from climatic loads improving so the fatigue resistance of the edge spacer assembly. For example, when the ambient temperature is increasing the gas inside the sealed interspace will expand and thanks to its properties, the viscoelastic part allows for the glass panes to move with respect to each other and releases stress in comparison with a system that does not comprise a viscoelastic part.
On the contrary, the stiffening effect may not be maximum in the prior art documents where transparent adhesives or seals are placed between each of the glass panes and the spacer and where no rigid connection is present. In the case of US20150151511 , the junction between the glass panes is ensured by a single transparent mass, which cannot alone bring at the same time a stiffening and a stress releasing effect. If the mass is viscoelastic, the stiffening of the IGU edge will be limited. If this mass is rigid, it will lead to the above described concentration of the mechanical stresses induced by the glass panes deformation resulting from the climatic load in the IGU edge. It may lead to cracks and/or breakage of the IGU or it may impose the use of thermally treated or chemically tempered glass panes. The present invention advantageously allows the use of a large variety of glass panes in addition to thermally treated or chemically tempered glass panes.
In a preferred embodiment of the invention, the transparent side of the edge spacer assembly comprises at least two and at most three piled and connected transparent parts comprising at least one and at most two transparent stiffening parts and one single transparent sealing part. The use of two or three parts is advantageous in terms of manufacturing efficiency. Furthermore, limiting the number of piled parts possibly having different refractive indexes advantageously limits the optical distortion through the assembly.
In a preferred variant of this embodiment, the transparent side of the edge spacer assembly comprises two piled and connected transparent parts. It comprises one single transparent stiffening part comprising the top surface (S1) and a second opposite surface (Sa) and one single transparent sealing part comprising the bottom surface (S2) and a second opposite surface (Sb). In this preferred embodiment, the top surface (S1) of the stiffening part is rigidly connected to the first glass pane, the second surface (Sa) of the stiffening part is connected to the second surface (Sb) of the sealing part and the bottom surface (S2) of the sealing part is connected to the second glass pane. The sequence is glass pane/stiffening part/sealing part/glass pane. The rigid connection between the top surface (S1) of the stiffening part and the first glass pane may be performed by means selected from a glue, soldering, welding or by molding and crosslinking the stiffening part on the glass pane or by applying the stiffening part as a hot melt on the glass pane. Glue is suitable to connect almost all types of stiffening parts to the glass pane, excepted curable materials that are generally liquid before curing. Curable materials will rather be molded on the glass pane and cured. Nevertheless, a previously crosslinked/cured material may also be glued to the glass pane. Soldering or welding is for instance suitable for stiffening parts comprising glass or thermoplastic polymers while thermoplastic polymers may also be applied as hot melts to the glass pane. The rigid connection between the top surface (S1) of the stiffening part and the first glass pane is preferably performed by means of welding or by molding and crosslinking the stiffening part on the glass pane or by applying the stiffening part as a hot melt on the glass pane. Stiffening parts having complex shapes may be used.
In another preferred variant of this embodiment, the transparent side of the edge spacer assembly comprises three piled and connected transparent parts. It comprises a first stiffening part comprising the top surface (S1) and a second opposite surface (Sc), one single sealing part having a first surface (Sd) and a second opposite surface (Se) and a second stiffening part comprising a first surface (Sf) and the bottom surface (S2). In this embodiment, the top (S1) and bottom (S2) surfaces are rigidly connected to the first and second glass panes, the second surface (Sc) of the first stiffening part is connected to the first surface (Sd) of the sealing part and the second surface (Se) of the sealing part is connected to the first surface (Sf) of the second stiffening part. The sequence is glass pane/stiffening part/sealing part/stiffening part/glass pane. In this variant, the two stiffening parts may comprise the same or different transparent rigid materials. Stiffening parts with complex shapes may be used. The two stiffening parts are rigidly connected to the glass panes by the same means as in the preferred variant above. In the present variant, the sealing part may be introduced in the pile of parts in different ways. It may be connected to one or the other stiffening part. Alternatively, it may consist of two sub-parts, each one being connected to one of the two stiffening parts. The two sub-parts when put in contact form the sealing part. In this last case, the sealing part comprises a viscoelastic polymer having an intrinsic adhesive property as defined above.
In a preferred embodiment, the IGU is a double insulating glazing unit. In another preferred embodiment, the IGU is a triple insulating glazing unit comprising a third glass pane and still at least one edge spacer assembly according to the invention.
According to a further aspect of the invention, a glazed assembly is provided comprising one or more gas-filled IGU's according to the invention. By glazed assembly is meant any glazed construction comprising one or more gas-filled IGU's according to the invention for interior or exterior application such as a window, a door, a partition wall, a curtain wall, a roof , a temperature conditioned product presentation appliance such as a refrigerated cabinet, and the like.
They are also particularly suited for use in frameless glazed assemblies. By frameless glazed assembly is meant a glazed assembly having a higher transparent surface than a standard one by elimination of some or all frame elements. These assemblies may have a limited resistance to bending under load because of the elimination of said frame elements. The IGU's according to the invention advantageously are stiffened by the at least one stiffening part of the transparent side of the edge spacer assembly and its rigid connection to one of the glass panes, what improves the resistance to short term stresses. At the same time, the sealing part comprising a viscoelastic polymer allows for some deformation. Hence, the sealing part acts as a stress release component for releasing stress resulting from climatic loads improving so the fatigue resistance of the edge spacer assembly. Therefore the present invention also provides a frameless glazed assembly comprising one or more gas-filled insulating glazing units according to the invention.
In some embodiments, the frameless glazed assembly comprises at least two gas-filled insulating glazing units that are placed contiguous to each other, i.e. next to each other and in contact to each other. In this case, contiguous edges of contiguous IGU's are free from any frame element and the at least one transparent side of the edge spacer assembly of each insulating glazing unit is located along said contiguous edges. In some cases, the frameless glazed assembly comprises more than two gas-filled insulating glazing units that are placed contiguous to each other. In these cases, the contiguous edges of contiguous IGU's are free from any frame element and the edge spacer assemblies are transparent along these contiguous edges. Examples of such an application are ribbon windows, curtain walls, refrigerated cabinets.
The present invention has been described in terms of specific embodiments, which are illustrative of the invention and not to be construed as limiting. More generally, it will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and/or described hereinabove. The invention resides in each and every novel characteristic feature and each and every combination of characteristic features. Reference numerals in the claims do not limit their protective scope.
Use of the verbs "to comprise", "to include", "to be composed of", or any other variant, as well as their respective conjugations, does not exclude the presence of elements other than those stated.
Use of the article "a", "an" or "the" preceding an element does not exclude the presence of a plurality of such elements.

Description of the figures

Fig.1 is a front view of an IGU (1) according to the invention comprising a first (2) and a second (3) glass panes spaced apart by an edge spacer assembly (4) having one transparent side (8) along one of the glass panes edges.
Fig. 2 is a cross sectional view of an edge of an IGU (1) according to an embodiment of the invention. The cross sectional view shows a first (2) and a second (3) glass panes separated by a transparent side (8) of the edge spacer assembly and the interspace (5) between the glass panes. In Fig.1, the transparent side (8) of the edge spacer assembly comprises one transparent stiffening part (6) and one transparent sealing part (7). The stiffening part (6) is a crosslinked resin rigidly connected to the first glass pane (2) through the top surface S1 by molding and crosslinking a crosslinkable resin on the glass pane (2).
Fig. 3 is a cross sectional view of an edge of an IGU (1) according to another embodiment of the invention. The cross sectional view shows a first (2) and a second (3) glass panes separated by a transparent side (8) of the edge spacer assembly and the interspace (5) between the glass panes. In Fig.3, the transparent side (8) of the edge spacer assembly comprises two transparent stiffening parts (6,6') separated by one transparent sealing part (7). The stiffening parts (6,6') are made of a crosslinked resin rigidly connected to the first and second glass panes (2,3) through the top S1 and bottom S2 surfaces by molding and crosslinking a crosslinkable resin on the glass panes (2,3).
Fig. 4 is a front view of a frameless glazed assembly comprising three IGU's (1,1',1") that are placed contiguous to each other. The contiguous edges of the three IGU's (1,1',1") are free from any frame element. The sides (8,8',8",8‴) of the three edge spacer assemblies (4,4',4") along these contiguous IGU's edges are transparent providing a non-interrupted horizontal view through the frameless glazed assembly.

Claims

A gas-filled insulating glazing unit (1) comprising:
• a first (2) and a second (3) glass panes,

• an edge spacer assembly (4) extending between the first and second glass panes along their edges for holding them at a certain distance from each other and for sealingly coupling them so as to form a hermetically sealed interspace (5) between them,

• an insulating gas filling said interspace,
wherein said edge spacer assembly (4) has at least one transparent side (8) along one of the glass panes edges, and

said at least one transparent side (8) is characterized in that

it comprises at least two piled and connected transparent parts comprising:
• at least one transparent stiffening part (6) comprising a transparent rigid material having a Young's modulus of at least 0.5 GPa,

• one single transparent sealing part (7) comprising a transparent viscoelastic polymer having a Young's modulus lower than 0.5 GPa,

wherein the top surface (S1) and the bottom surface (S2) of the piled and connected transparent parts are connected respectively to the first (2) and the second (3) glass panes, and

wherein at least one of the top (S1) or bottom (S2) surface belongs to a transparent stiffening part (6) and is rigidly connected to the first (2) or the second (3) glass pane.
A gas-filled insulating glazing unit (1) according to claim 1 wherein the rigid material has a density of at least 0.5 g/cm³.
A gas-filled insulating glazing unit (1) according to any of the previous claims wherein the viscoelastic polymer has a loss coefficient of at least 0.1.
A gas-filled insulating glazing unit (1)according to claim 1 wherein, the transparent side (8) of the edge spacer assembly comprises two piled and connected transparent parts:
• one single transparent stiffening part comprising the top surface (S1) and a second opposite surface (Sa),

• one single transparent sealing part (7) comprising the bottom surface (S2) and a second opposite surface (Sb),
wherein,
the top surface (S1) of the stiffening part (6) is rigidly connected to the first glass pane (2), the second surface (Sa) of the stiffening part is connected to the second surface (Sb) of the sealing part (7) and the bottom surface (S2) of the sealing part is connected to the second glass pane (3).
A gas-filled insulating glazing unit (1) according to claim 4 wherein, the top surface (S1) of the stiffening part (6) is rigidly connected to the first glass pane (2) by means selected from a glue, soldering, welding or by molding and crosslinking said stiffening part (6) on the glass pane (2) or by applying said stiffening part (6) as a hot melt on the glass pane (2).
A gas-filled insulating glazing unit (1) according to claims 1 to 3 wherein, the transparent side (8) of the edge spacer assembly comprises three piled and connected transparent parts:
• a first stiffening part (6) comprising the top surface (S1) and a second opposite surface (Sc),

• one single sealing part (7) having a first surface (Sd) and a second opposite surface (Se),

• a second stiffening part (6') comprising a first surface (Sf) and the bottom surface (S2),
wherein,
the top (S1) and bottom (S2) surfaces are rigidly connected to the first (2) and second (3) glass panes, the second surface (Sc) of the first stiffening part (6) is connected to the first surface (Sd) of the sealing part (7)and the second surface (Se) of the sealing part is connected to the first surface (Sf) of the second stiffening part (6').
A gas-filled insulating glazing unit (1) according to claim 6 wherein, the top (S1) and bottom (S2) surfaces are rigidly connected to the first (2) and second (3) glass panes by means selected from a glue, soldering, welding or by molding and crosslinking said stiffening parts (6,6') on the glass panes (2,3) or by applying said stiffening parts (6,6') as a hot melt on the glass panes (2,3).
A gas-filled insulating glazing unit (1) according to any of the preceding claims wherein, the at least one transparent stiffening part (6) comprises a transparent rigid polymer.
A gas-filled insulating glazing unit (1) according to the preceding claim wherein, the at least one transparent stiffening part (6,6') comprises a transparent rigid polymer selected from a polymethyl methacrylate (PMMA), a polycarbonate (PC), a polystyrene (PS), a polyvinyl chloride (PVC), a polyamide (PA), a polyetherimide (PEI), a polyethylene terephthalate (PET), a polyurethane, an acrylonitrile butadiene styrene copolymer (ABS), a styrene acrylonitrile copolymer (SAN), a styrene methyl methacrylate copolymer (SMMA) and any mixtures of these; or a crosslinked resin.
A gas-filled insulating glazing unit (1) according to any of the preceding claims wherein, the transparent sealing part (7) comprises a transparent viscoelastic polymer selected from polyurethanes, polyethylenes, polyvinylbutyral (PVB), ethylene vinyl acetate copolymer (EVA), neoprene, isoprene, polyisobutene, acrylics.
A gas-filled insulating glazing unit (1) according to the preceding claim wherein said transparent polymer is used in the form of a double-sided adhesive tape in which the core of the tape is made of said transparent polymer selected from an acrylic polymer or an acrylic polymer foam.
A gas-filled insulating glazing unit (1) according to any of the preceding claims that is a triple glazing unit comprising a third glass pane.
A glazed assembly comprising one or more gas-filled insulating glazing units (1) according to any of the preceding claims.
A glazed assembly according to the previous claim, wherein the glazed assembly is a frameless glazed assembly (9).
A frameless glazed assembly (9) according to the preceding claim comprising at least two gas-filled insulating glazing units (1,1') that are placed contiguous to each other and wherein contiguous edges of said contiguous insulating glazing units (1,1') are free from any frame element and wherein the at least one transparent side (8,8') of the edge spacer assembly (4,4') of each insulating glazing unit is located along said contiguous edges.
A glazed assembly according to any of claims 13 to 15, wherein the glazed assembly is a temperature conditioned product presentation appliance.