FR2951992A1 - COMPOSITE SANDWICH PANEL COMPRISING A VISCOELASTIC HEAVY MATERIAL LAYER - Google Patents

Abstract

The invention relates to a composite panel (10) sandwich type. The invention is characterized in that it comprises: a first facing (12); a layer of polyethylene foam (14); a layer of viscoelastic heavy material (16); a layer of material (18) having a first dynamic stiffness; a first material layer (20) having a second dynamic stiffness greater than the first dynamic stiffness; and - a second facing (22).

Description

The present invention relates to the field of sandwich type composite panels comprising a central heat-insulating core disposed between two rigid cover plates.

The panel according to the present invention is intended to be assembled with other panels to constitute in particular a cover wall (facade or roof for verandas, balconies, terraces, galleries or other), a filling wall, or any other type of wall. Such walls are generally placed outside, in a vertical direction, horizontal or inclined and are therefore likely to be subjected to rain, hail or any external aggression generating noise, including impact noise. These noise nuisances, whether due to impacts or noises surrounding, are transmitted, at least in part, the panels into the interior space delimited by these panels. Already known, in particular FR 2,834,738, composite panels having sound insulation properties. An object of the present invention is to provide a composite sandwich panel thermally insulating and has improved sound insulation. The invention achieves its object by the fact that the composite panel according to the invention comprises: a first facing; a layer of polyethylene foam; a layer of viscoelastic heavy material; a material layer having a first dynamic stiffness; a first material layer having a second dynamic stiffness greater than the first dynamic stiffness; and a second facing. Preferably the first facing is intended to be turned towards the outside of a room or room, while the second facing is intended to be turned towards the inside of said room or room. Preferably, the polyethylene foam layer is disposed between the first facing and the layer of viscoelastic heavy material, the other layers being positionable at different locations in the panel, it being understood that the facings are always located on both sides of all the layers. According to a preferred embodiment, the material having a first dynamic stiffness is a thermally insulating material, while material having a second dynamic stiffness is also preferably a thermally insulating material. The presence of the layer of polyethylene foam associated with the layer of heavy viscoelastic material so as to form a complex is particularly advantageous, especially when the panel according to the invention is used as a veranda roof panel. Indeed, thanks to the contact of the polyethylene foam with the first facing, the outer facing, it becomes possible to use dark colors on the outside of the panel while limiting the risk of delamination, especially due to the rise in temperature, especially during the summer period. In addition, the polyethylene advantageously makes it possible to lower the temperature of the bonding plane of the first facing interface / layers of insulating material and thus to reduce the risk of rupture of the bonding plane.

Moreover, the layer of heavy viscoelastic material, provides a mass / spring effect which the inventors have found that it improves the acoustic performance of the panel. Compared to a standard panel consisting of two faces of sheets and a polystyrene core, provides a rain impact performance of about 71 dB (A), while the panel according to the invention, provides an impact performance rain less than 62 dB (A). In other words, the panel according to the invention provides about 13 dB (A) compared to a conventional panel, it being understood that a reduction of 3 dB (A) corresponds to halving the acoustic intensity.

Preferably, the polyethylene foam layer and the heavy viscoelastic material layer form a complex. Furthermore, the fact that the second dynamic stiffness is greater than the first dynamic stiffness makes it possible to achieve another mass / spring effect between the layer of material having a first dynamic stiffness and the layer of material having a second dynamic stiffness.

It is specified that the dynamic stiffness characterizes a dynamic spring: the lower the dynamic stiffness, the more the spring is flexible, and similarly the higher the dynamic stiffness, the stiffer the spring.

Therefore, according to the invention, the "spring" is the layer of material having a first dynamic stiffness. Moreover, the greater the first dynamic stiffness is lower than the second dynamic stiffness, the lower the mass-spring resonance frequency is low and the important filtering above this resonance frequency.

Advantageously, at least one of the first and second facings is made of aluminum. Preferably, the first facing is made of a composite material, while the second facing is made of aluminum. In another variant the first and second facings are both made of aluminum. Particularly advantageous acoustic performances have been obtained when the polyethylene foam layer has a thickness substantially between 1 and 5 mm. These performances are further improved when the polyethylene foam layer is of the crosslinked type, and has a density substantially between 60 and 160 kg / m3. The thickness of the layer of heavy material will preferably be chosen between 1 and 6 mm. Preferably, the layer of heavy material has a density of between 2 and 12 kg / m 2.

It is specified that the heavy mass may for example be made in a viscoelastic material EPDM / EVA type, composed of rubber, mineral fillers and paraffinic oil. According to a first embodiment, the layer of material having a first dynamic stiffness has a thickness that is substantially equal to the thickness of the first layer of material having a second dynamic stiffness. Preferably, the thickness of the material layer having a first dynamic stiffness is between 20 and 40 mm. In this first embodiment, it is understood that the core 35 comprises four layers.

In a variant of this first embodiment, the layer of material having a first dynamic stiffness is disposed between the second facing and the first layer having a second dynamic stiffness.

Advantageously, the thickness of the first layer of material having a second dynamic stiffness is at least 150% of the thickness of the layer of material having a first dynamic stiffness. According to a second embodiment, the composite panel further comprises a second material layer having a second dynamic stiffness, which is disposed between the heavy material layer and the material layer having a first dynamic stiffness. Preferably, the material of this second layer is the same as that of the aforementioned first layer.

Advantageously, the first and second layers of material having a second dynamic stiffness have substantially the same thickness, preferably between 10 and 20 mm. In this second embodiment, the material layer having a first dynamic stiffness has a thickness substantially double that of one or the other of the first and second material layers having a second dynamic stiffness. The second layer of material having a second dynamic stiffness makes it possible to create a mass-spring-mass phenomenon which the inventors have found that it makes it possible to provide a panel having acoustic performances that are even better than those of the first embodiment of the panel. The inventors have also found that for these thicknesses, the acoustic performance of the panel is particularly advantageous.

In the two embodiments mentioned above, the material having a first dynamic stiffness is preferably expanded polystyrene, preferably of the graphite-elasticized type. This particular choice makes it possible to further improve the acoustic properties of the panel. Furthermore, the material having a second dynamic stiffness is preferably extruded polystyrene.

Whatever the chosen materials, it is preferred that the ratio between the second dynamic stiffness and the first dynamic stiffness is greater than or equal to ten, preferably one hundred. The invention will be better understood and its advantages will appear better on reading the following description of two embodiments given by way of non-limiting examples. The description refers to the accompanying drawings in which: - Figure 1 is a sectional view of the edge of a panel according to a first embodiment of the invention; - Figure 2 is a variant of the panel of Figure 1; - Figure 3 is a sectional view of the edge of a panel according to a second embodiment of the invention; - Figure 4 is a variant of the panel of Figure 3; and FIG. 5 is a sectional view of the edge of a panel according to another variant of the panel of FIG. 1. The composite panels illustrated here are of sandwich type, that is to say that they are formed. by a stack of different layers attached to each other. Their function is to form an acoustic barrier to improve the well-being of the occupants of the room equipped with such panels. With the help of Figures 1 and 2, we will first describe a first embodiment of the invention. The composite panel 10 firstly comprises a first facing 12 made of aluminum which is intended to be turned outwards. The first facing is made of aluminum and has a thickness of 0.7mm. On the facing 12 is bonded a complex consisting of a layer of polyethylene foam 14 having a thickness e2 of the order of 3 mm and a layer 16 of viscoelastic heavy material having a thickness of about 3.5 mm and a density of about 7 kg / m2.

It is specified that the polyethylene foam and the viscoelastic heavy material are in the form of a complex. It is also specified that the layer of polyethylene foam 14 is immediately adhered to the first layer 12. In addition, the panel 10 further comprises a layer 18 of expanded polystyrene of the graphite-elasticated type which is juxtaposed to the layer of heavy material. This layer 18 of expanded polystyrene has a thickness e3 of about 30 mm and a first dynamic stiffness of the order of 10 to 15 MN / m3. The layer 18 of expanded polystyrene is adhered to an extruded polystyrene layer which has a thickness e4 of about 30 mm. Expanded polystyrene has a second dynamic stiffness which is about one hundred times greater than the dynamic stiffness of the above-mentioned expanded polystyrene. Finally, as seen in Figure 1, the extruded polystyrene layer is glued to a second facing, the inner facing. It is also made of aluminum and has a thickness of about 0.7 mm. FIG. 2 illustrates a panel 10 'which is a variant of the panel 10 of FIG. 1. It is distinguished by the fact that the first facing 12 (outer facing) of aluminum is replaced by a composite facing 12' having a thickness e ' 1 of the order of 3 mm. The tests performed on the panel 10 of the first embodiment show that it has a rain impact acoustic performance of between 59 and 60 dB (A). With the help of Figures 3 and 4, we will now describe a second embodiment of the composite panel 100 according to the invention. The panel 100 has an outer cladding 102 of aluminum, similar to the first cladding 12 of the panel 10 described above. It further comprises a complex 104/106 consisting of polyethylene foam and a viscoelastic heavy mass, this complex being attached to the outer skin 102 as in the panel 10 of the first embodiment. Referring to Figure 3, it is understood that the composite panel 100 further comprises a first extruded polystyrene layer 108 which is attached to the layer 106 of heavy material. This extruded polystyrene layer 108 has a thickness e5 of the order of 15 mm. It is also pointed out that in this example it is the same extruded polystyrene as that used in the panel 10 described above. The first layer of extruded polystyrene is adhered to a layer of expanded polystyrene 110 which has a thickness e6 of about 30 mm, thus twice the thickness e5. Except for its thickness, the expanded polystyrene used here is identical to that used in the first embodiment. The composite panel 100 further comprises a second layer of extruded polystyrene 112 which is bonded to the expanded polystyrene layer 110. This second layer 112 has a thickness e7 of about 15 mm, that is to say substantially identical to the e5 thickness of the first layer of extruded polystyrene. Finally, the composite panel 100 also comprises an inner facing 114 of aluminum having a thickness of about 0.7 mm, this inner face being bonded to the second extruded polystyrene layer 112. FIG. of the composite panel 100 of Figure 3. The panel 100 'shown therefrom differs from the composite panel 100 in that the outer face 102' is constituted by a composite plate of thickness e1 of about 3 mm and not by an aluminum plate. The acoustic tests performed on the composite panel of the second embodiment show that it has a rain impact acoustic performance of less than 58 dB (A), which is slightly better than the performance of the composite panel 10 of the first embodiment. With the help of Figure 5, we will describe a variant of the first embodiment of the panel of the invention. The panel 200 of FIG. 5 differs from the panel 10 of FIG. 1 in that the layer 208 of material having a first dynamic stiffness, in this case of the elasticized expanded polystyrene, is disposed between the second facing 212 and the first layer 210 of material having a second dynamic stiffness, in this case extruded polystyrene.

In the example of Figure 5, the thickness e1O of the extruded polystyrene layer 210 (30 mm) is substantially equal to twice the thickness eh of the layer of expanded polystyrene elasticized (15 mm). Furthermore, it is found that the extruded polystyrene layer 210 is bonded to the complex formed of the polyethylene foam layer and the viscoelastic heavy material layer 206.

Claims (20)

REVENDICATIONS1. Composite panel (10, 10 ', 100, 100', 200) sandwich type characterized in that it comprises: - a first facing (12, 12 ', 102, 102', 202); a layer of polyethylene foam (14, 104, 204); a layer of viscoelastic heavy material (16, 106, 206); a layer of material (18, 110, 208) having a first dynamic stiffness; a first material layer (20) having a second dynamic stiffness greater than the first dynamic stiffness; and - a second siding (22,114,212). 15 2. Composite panel according to claim 1, characterized in that at least one of the first and second facings (12,12 ', 102,102'; 22,114,202,212) is made of aluminum. 3. Composite panel according to claim 1 or 2, characterized in that the first cladding (12,12 ', 102,102', 202) is made of a composite material. 4. Composite panel according to any one of claims 1 to 3, characterized in that the layer of polyethylene foam (14,104) has a thickness (el) substantially between 1 and 5 mm. 5. Composite panel according to any one of claims 1 to 4, characterized in that the layer of polyethylene foam (14,104) is of the crosslinked type, and has a density substantially between 60 and 160 kg / m3. 6. Composite panel according to any one of claims 1 to 5, characterized in that the layer of heavy material (16,106) has a thickness (e2) of between 1 and 6 mm. 10 7. Composite panel according to any one of claims 1 to 6, characterized in that the layer of heavy material (16,106) has a density of between 2 and 12 kg / m2. 8. Composite panel according to any one of claims 1 to 7, characterized in that the material layer (18) having a first dynamic stiffness has a thickness (e3) which is substantially equal to the thickness (e4) of the first layer of material (20) having a second dynamic stiffness. 9. Composite panel according to claim 8, characterized in that the thickness (e4) of the material layer (18) having a first dynamic stiffness is between 20 and 40 mm. 10. Composite panel (10) according to any one of claims 1 to 9, characterized in that the first layer of material having a second dynamic stiffness (20) is disposed between the layer having a first dynamic stiffness (18) and the second siding (22). 11. Composite panel (200) according to any one of claims 1 to 9, characterized in that the layer of material having a first dynamic stiffness (208) is disposed between the first layer of material having a second dynamic stiffness (210) and the second siding (212). 12. Composite panel according to claim 11, characterized in that the thickness (e10) of the first layer of material having a second dynamic stiffness (210) is at least 150% of the thickness (eh) of the layer. of material having a first dynamic stiffness (208). 13. Composite panel according to any one of claims 1 to 7, characterized in that it further comprises a second layer of material (108) having a second dynamic stiffness, whichisdisposed between the layer of heavy material (106) and the material layer (110) having a first dynamic stiffness. 14. Composite panel according to claim 13, characterized in that the first and second layers of material (108,112) having a second dynamic stiffness have substantially the same thickness. 15. Composite panel according to claim 14, characterized in that the first and second layers of material having a second dynamic stiffness have a thickness (e5, e7) substantially between 10 and 20 mm. Composite panel according to claim 14 or 15, characterized in that the material layer (110) having a first dynamic stiffness has a thickness substantially double that of either of the first and second layers of material having a second dynamic stiffness. 17. Composite panel according to any one of claims 1 to 16, characterized in that the material having a first dynamic stiffness is expanded polystyrene. 18. Composite panel according to claim 17, characterized in that the expanded polystyrene is of the graphite-elasticized type. 19. Composite panel according to any one of claims 1 to 18, characterized in that the material having a second dynamic stiffness is extruded polystyrene. 20. Composite panel according to any one of claims 1 to 19, characterized in that the ratio between the second dynamic stiffness and the first dynamic stiffness is greater than or equal to ten.