SE501625C2 - Composite glazing panel, which offers high acoustic damping as well as ways of producing the same - Google Patents

Abstract

A composite glazing panel affording high acoustic attenuation comprises two sheets (1, 8) of vitreous material between which is sandwiched a layer (7) of an aerogel which sandwich is bonded together as a monolithic laminate. The layer of aerogel (7), for example of a silica aerogel, may be formed directly onto a first vitreous sheet (1) so that it bonds directly to that sheet, and a second vitreous sheet (8) may be bonded to the aerogel by means of an adhesive layer (9), suitably formed using a solvent-free powder adhesive. The edges of the panel may be hermetically sealed using a mastics sealant (10). <IMAGE>

Description

10 15 20 25 30 35 5.01 625 2 a high specific mass is required (ie mass per unit area).

As an example only, such panels are again unsuitable for to mount in walls, where weight considerations are an important factor.

It is an object of the present invention to achieve a composite glazing panel, which offers a very high, degree of acoustic attenuation in relation to its total thickness and specific mass.

According to the invention, a composite glazing panel is intended, which offers high acoustic attenuation, and is characterized by such panel comprises two sheets of glassy material between which a layer of an airgel is inlaid, which layered material is bonded together like a monolithic laminate.

The term "monolithic laminate" is used herein to denote a laminate that is bonded together in such a way that it vibrates in the same way as a single disc of a material with a modulus of elasticity, which can be calculated from the elasticity the modules and thicknesses of the individual layers in the laminate. Such monolithic laminates can be contrasted relation to hollow panels and to laminate as only are weakly connected so that in vibration they behave as a box instead of as a plate. In a monolithic lami- Thus, there is no resonant "mass cavity". IllâSSä ".

Such a composite glazing panel offers a very high degree of acoustic attenuation in relation to its total thickness and specific mass.

Such a panel also has the advantage of ensuring that both the main surfaces of the airgel layer are protected from the atmosphere humidity. Aerogels generally absorb moisture vigorously. tig, after which they have a tendency to crack and break dust. The edges of such a laminate can be easily protected on one 10 15 20 25 30 35 501 625 3 known per se by using a moisture resistance standing sealant, such as a silicone-based cementitious preparation.

A further object of this invention is to provide come a way to manufacture such a panel.

Thus, the present invention also relates to a method of operate a composite glazing panel, which offers high acoustic attenuation, and is characterized by a layer of an aerobic gel is placed between two sheets of glassy material and it layered material is bonded together as a monolithic laminar nat.

This is a very simple way to manufacture such a panel.

The areogel used may be an alumina aerogel, zirconia, stannous oxide or tungsten oxide, but the is preferably made of an aerogel based on silica. For to form a plate of airgel to be part of one laminate, spread a layer of the appropriate gel in a onto a suitable forming plate and solvent the agent is removed from the layer and leaves an airgel plate.

In a preferred manner, a gel of silica is dispersed in alcohol as a solvent onto a forming plate, which then introduced into an autoclave. The anthoclave is pressurized and the gel is optionally flushed with liquid carbon dioxide to replace all or most of the alcohol solvent. The pressure in the autoclave is increased to a pressure greater than the critical pressure for the solvent present in the layer (about 80 bar for alcohol or about 74 bar for carbon dioxide). The temperature i the autoclave is then raised to above the critical temperature for that solvent (about 240 ° C for alcohol or about 31 ° C for carbon dioxide). in this way it is possible to remove the solvent from the layer without collapsing the silicon the structure of the dioxide to form the airgel and the airgel structure can actually contain up to about 98% of the 10 15 20 25 30 35 5.01 625 4 volume. The airgel plate obtained from this method is laid then between two glassy discs and the layer material bonded together as a monolithic laminate to form a panel according to the invention.

Panels according to the invention may be opaque, for example they may shaped as decorative panels, which can be colored by include colorants in the airgel or otherwise, but preferably the layered material is bonded to form a light-transmitting laminate. If the laminates are light permeable, it can be used as a window closure or elsewhere where light transmission is an important factor.

Depending on the thickness of the airgel within the laminate, it can also be transparent.

Care must be taken when connecting a preform layer of an airgel to a glass plate. If a solvent based adhesive was used, it is likely that the solvent could penetrate the airgel and this would cause that the matrix of the airgel is broken down to a large extent the same way that would happen with the absorption of moisture. MAN therefore prefers that the binder be substantially free from solvent. Thus, it is preferred to use one in heat soft or fusible adhesive material. Airgel is well able to withstand temperatures at the levels required breed for melting many in heat softening adhesive material. Such heat-softenable adhesives can be in the form of a thin disc or film, but it is advantageous that the adhesive is in powder form as this simplifies handling ring problem. Such a powdery adhesive material can be easily applied, for example, by an electrostatic shower technology well known per se. Fusible silicone resins are particularly well adapted to form a highly efficient bond between silica-based aerogels and glassy disks, which are also rich in silica. 10 15 20 25 30 35 501 625 5 In particularly preferred embodiments of the invention bind it or at least one such airgel layer directly to such a glassy disc. This avoids any problem in selecting and applying an intermediate layer of adhesive the materials and greatly facilitates production. The The easiest way to ensure such direct binding is to use such a glassy disc as the forming plate on which airgel layer is first formed. In this way is formed the airgel layer or at least one such layer directly on one such a glassy disc so that it is directly bonded thereto.

A silica-based airgel will easily bind directly to the vitreous silica matrix of, for example, a glassy disc.

In some preferred embodiments the invention comprises the laminate two airgel layers, each directly bonded to such a glassy disc. By mounting two airgel layers, each directly formatted on such a glassy disc for to form the laminate, a panel can be easily formed having one very high degree of acoustic attenuation relative to it thickness and weight.

The acoustic attenuation over a glazing panel according to the invention is believed to be due in large part to the very large one the difference in acoustic impedance such as between the airgel and it glassy material due to the very low sound speed hot in airgel. However, to take full advantage of this phenomenon, the airgel layer (s) should not be too thin and it is thus preferred that the airgel layer or at least such an airgel layer is at least 10 mm thick. If increases the thickness of such an airgel layer is also a lot favorable for thermal insulation if this would be desirable.

It should be noted, however, that airgel layers transfer a significant proportion of light in a diffuse way and therefore it should total thickness of the airgel in a panel should not be too large if a high degree of resolution through the panel is considered important. 10 15 20 25 30 35 5.01 625 6 In order to protect the airgel completely against possible attack by atmospheric dye moisture, it is preferred that the airgel be hermetically sealed. within the laminate. This can be done in different ways, for example by use a cement-type edge seal as previously mentioned, optionally in conjunction with a U-frame, for example of extruded aluminum nium. Preferably, however, the laminate is hermetically sealed. by means of one or more spacers extending around the panel and are soldered to the glassy discs in the laminate. This provides a very effective and long lasting protection of the airgel.

In certain preferred embodiments of the invention, there the airgel is hermetically sealed through the laminate it is evacuated interior of the laminate.

This is very favorable from the point of view of thermal insulation and it can also have a useful advantage in allowing one more safe preservation of the very low sound propagation rate hot in airgel.

Preferred embodiments of the invention will now appear described only as examples with reference to the accompanying schematic drawings where: Fig. 1 shows a stage in the manufacture of a panel in in accordance with this invention and Figs. 2 and 3, respectively. finally shows cross sections through two embodiments of a panel according to the present invention.

A glassy disc 1 of suitable size and shape has one dam frame 2 placed around its periphery (compare fig. l) ñ The space formed above the disc 1 and within the dam 2 then filled with an airgel-forming solution. As shown in Fig. 1, the disc 1 is then placed inside an autoclave 3, provided 10 15 20 25 30 35 501 625 7 with a gas inlet 4 and outlet valves 5 and a heating device shown at 6.

The solution used is an alcohol solution, i.e. a solution in alcohol. The gel-forming solute may be silicon. dioxide alone or it may have additives of other oxides, for example of aluminum, tellurium, germanium or other materials for to achieve special desired properties on the airgel, which to be formed.

After the aerogel-forming solution has been poured out and any bubbles removed are allowed to form a solution gel and age. The alcohol gel thus formed is flushed with liquid carbon dioxide, which replaces the alcohol in the alcohol solution one. This can be done by repeatedly rinsing the gel solution at about 18-20 ° C at a pressure of about 55 bar. This has the advantage of greatly simplifying the next manufacturing step.

The pressure inside the autoclave 3 is then increased to above the critical pressure for the solvent, 74 bar for carbon dioxide and temperature the turn within the autoclave is then increased to above the critical the temperature 3l ° C for carbon dioxide. This step is simplified by to replace the solvent with carbon dioxide, because if the solvent would remain alcohol, the temperature and the pressure required to be above 240 ° C and 80 bar resp. Repre- critical critical temperatures for this step in the The process is about 40 ° C for carbon dioxide and about 270 ° C for alcohol as a solvent. Carbon dioxide was suitably used as pressurizing gas, supplied via inlet valve 4. Under drying of the layer, part of the steam within the autoclave is allowed to escape via outlet valve 5 and upon completion of drying is left a layer of airgel 7 directly bonded to the disc 1.

The layer of airgel 7 is then laid between the first sheet 1 and a second glassy disc. 10 15 20 25 30 35 E ~> 01 625 8 Fig. 2 shows such a panel where the airgel layer 7 is bonded to a second sheet 8 of glass via an intermediate layer of adhesives 9. Such bonding is accomplished by electrostatically spray a layer of powdered silicone resin on the airgel layer 7, mount the second disc 8 against it adhesive and heat the assembly to achieve melting the resin so that upon cooling the layered material the bond is bonded together as a laminate. The panel is completed by placing a silicone-based cementitious material 10 into the inwardly facing space between the airgel layer 2 and the first the disc 1 left when removing the dam frame 2 (Fig. 1).

Fig. 3 shows a second embodiment of panel, which is formed by bonding together two layers 7 of airgel, each formed on and directly bonded to a glassy disc 1. Like the laminate of Fig. 2, the laminate of Fig. 3 is bonded together by means of an adhesive layer 9, which is suitably formed in the same way.

Each of the vitreous disks 1 in Fig. 3 carries one metallization layer of copper on the edge covered by a layer solder, these being shown together at ll. These layers ll applied before the airgel layers 7 were formed and they was masked through the dam frames 2 to form such airgel layers. After bonding the laminate together, soldered metal spacer bands 12 between the metallized / solder layers around the edge of the panel, so that the airgel layers hermetically sealed from the surrounding atmosphere. The interior of the panel can then evacuated if desired.

Such panels offer neither according to Fig. 2 nor Fig. 3 a very high degree of acoustic attenuation with respect to their total thickness and their weight per unit area and they offer also excellent thermal insulation.

In a variant of the embodiment shown in Fig. 3, the not directly between the two glassy discs but 10 15 501 625 9 instead, it is corrugated to extend the thermal conductivity. the path between these discs around their edges.

In a further variant of the panel either according to Fig. 2 or Fig. 3, the sealing material 10 in Fig. 2 is omitted or the metallized band 11 and the spacer 12 in FIG. 3. Instead, the two glass sheets were "soldered" together by a glass joint.

It will be appreciated that a laminate as shown in Fig. 2 or 3 may mounted on one or more additional elements to form a panel of more complex construction if desired.

In particular, such a more complex panel may comprise one or several additional glass sheets such as 1, supporting one directly formed layer 7 of airgel.

Claims (13)

10 15 20 25 30 É01 625 10> Patentkrav A composite glazing panel, which offers high acoustic attenuation, is characterized in that such a panel comprises two sheets of glassy material between which a layer of an airgel is inserted, which layer material is joined together as a monolithic laminate. Panel according to claim 1, characterized in that the laminate is transparent. Panel according to Claim 1 or 2, characterized in that a fusible silicone resin is used as the adhesive material for bonding layers in the laminate. Panel according to any one of the preceding claims, characterized in that the airgel layer or at least one such airgel layer is directly bonded to such a glassy disc. Panel according to claim 4, characterized in that the laminate comprises two airgel layers, each directly bonded to such a glassy board. Panel according to one of the preceding claims, characterized in that the airgel layer or at least one such airgel layer is at least 10 mm thick. Panel according to any one of the preceding claims, characterized in that the airgel is hermetically sealed within the laminate and wherein the laminate is hermetically sealed by means of one or more spacers extending around the panel and soldered to the glassy sheets of the laminate. of that Panel according to claim 7, characterized in that the interior of the laminate is evacuated. 10 15 20 25 501 625 11 9. A method of manufacturing a composite glazing panel which offers high acoustic attenuation, characterized in that a layer of an airgel is inserted between two sheets of glassy material and that the layer material is bonded together as a monolithic laminate. 10. A method according to claim 9, characterized in that a substantially solvent-free, fusible adhesive material is used as the adhesive material for bonding layers in the laminate, preferably a powdered adhesive material. 11. A method according to claim 9 or 10, characterized in that the airgel layer or at least one such airgel layer is formed directly on such a glassy disc, so that it becomes directly bonded thereto. 12. A method according to claim 11, characterized in that the laminate is formed by mounting two airgel layers, each directly formed on such a glassy disc. 13. A method according to any one of claims 9-12, characterized in that the airgel is hermetically sealed within the laminate and wherein the laminate is hermetically sealed by means of one or more spacers extending around the panel and soldered to the glassy sheets of the laminate.