FR2780334A1 - Composite panel e.g. for wall cladding or roofing - Google Patents

Abstract

The panel is made from rigid outer (2) and inner (3) skins with a layer of plastic foam (1) and a relatively thin multichannel layer (4) sandwiched between them. The multichannel layer is made from a rigid plastic which is a poor conductor of heat and has a melting point above the temperature resulting from its exposure to the sun's rays. The channels (4a), which are separated by thin partitions (4c), occupy over 80 per cent of the layer's surface area.

Description

Air stabilized composite panel.

  The present invention relates to a composite panel, for example of the kind

  of that described in document FR-A-2,755,162.

  Such composite panels are commonly used to make covers for verandas, terraces, roofs, balconies, galleries, walls (cladding), etc. They can also be used to produce various surfaces such as special ceilings, insulating partitions, insulating vehicle bodies, advertising panels, etc. Composite panels of this kind mainly comprise a rigid foam core of relatively thick plastic material (of the order of 50 millimeters) disposed between two rigid facings, metallic or otherwise, and assembled to the latter by gluing, for example by means of structural adhesives. In general, these composite panels are applicable to the production of surfaces or walls which can have various functions, exposing them indifferently to sunshine and / or runoff, these surfaces being able to be arranged horizontally, more or less inclined or upright; they

  can be worn or self-supporting.

  With the device described in the document FR-A-2,755,162 mentioned above, the problem of sealing at the junction of panels of this kind has been resolved, which is perfectly ensured regardless of the size of the volume.

  of water running down on the surfaces made up of such panels.

  However, the use of composite panels of the type indicated above, can raise problems when these are called upon to constitute surfaces exposed to solar radiation. Indeed, these panels have the drawback, when subjected to the action of a more or less intense heat source such as the heat emitted by the sun, to absorb this heat by means of their external facing. which heats up very quickly and whose temperature can rise considerably. This radiating effect is further reinforced by the use of dark colors for the coating of the external facings of these composite panels. When the external metal facing of the insulating panel exceeds a critical temperature threshold, generally 70 ° C., the core of plastic foam included between said facing and which is rigid at average temperatures, softens and can become detached from said external facing; it no longer ensures the holding of the entire insulating panel, the rigidity and,

  above all, flatness, can be irreversibly altered.

  A similar drawback is encountered with composite panels having a relatively thin core (for example of the order of a few

  millimeters) arranged between two rigid facings.

  An object of the present invention is therefore, in particular, to remedy this drawback. According to the invention applied to the composite panel comprising a relatively thick plastics foam core, this object is achieved by virtue of an insulating panel, preferably of the composite panel type comprising, in a manner known per se, a rigid foam core of material plastic, disposed between a rigid external facing and a rigid internal facing, this panel being remarkable in that said external facing and said foam core are separated by a plate in which is formed a plurality of voids. Preferably, a plate made of plastic material, crossed by multiple parallel channels between them and regularly distributed, is arranged at the interface between the external facing called to receive the sun's rays and the core of plastic foam. This plate is known per se and commonly known as "cellular polypropylene". It is understood that the invention allows natural ventilation inside the insulating panel and, consequently, a lowering of the temperature at the level of the foam core, a strengthening of the mechanical characteristics of said panel preserving its flatness, an increase in the level of acoustic damping, and also constitutes a thermal barrier. The soul of

  foam is protected from excessive heat.

  According to another characteristic arrangement of the invention applicable to composite panels comprising a relatively thin core disposed between two rigid facings, a plate made of plastic material, crossed by multiple channels parallel to each other and regularly distributed, is disposed at the interface between the facing external called to receive the solar rays and the internal facing, and assembled to said facing by gluing, preferably at

io means of structural adhesives.

  Facings, alveolar polypropylene sheet and rigid plastic foam core are assembled by gluing, preferably by means of structural adhesives. The goals, features and benefits above, and more,

  will emerge more clearly from the description which follows and from the appended drawings in which:

  Figure 1 is an end view of a portion of composite panel according to the invention of the kind comprising a rigid foam core of relatively thick plastic material (of the order of 50 millimeters) disposed between two rigid facings. Figure 2 is a top view with partial cutaway of the outer facing and the upper sole of the ventilation plate of this portion of

composite panel.

  Figure 3 is an end view of a portion of composite panel according to the invention of the kind comprising a relatively thin core disposed between two

rigid facing.

  Reference is made to said drawings to describe an interesting example of embodiment,

  although in no way limiting, of a composite panel according to the invention.

  This composite panel usually comprises a core 1 of rigid plastic foam such as polyurethane foam, polyvinyl chloride foam, extruded polystyrene, etc., disposed between two skins or rigid facings 2, 3, for example formed by steel or aluminum plates lacquered or covered with any other suitable coating. Siding 2, 3, could

  be made of any other suitable rigid material such as reinforced polyester or other.

  io One of these facing (reference 2) called to be oriented towards the outside will be called "external facing" in the rest of this presentation, while the other

  facing (reference 3) will be called "internal facing".

  According to the invention, the core of plastic foam 1 and the external facing 2 are separated by a plate 4 in which is formed a plurality of voids 4a, this plate being made of a material constituted by a plastic material which is poorly conductive of heat. and having a melting temperature higher than

  temperatures resulting from exposure of the panels to solar radiation.

  According to another embodiment of the composite panel applicable to composite panels of the type comprising a relatively thin core, said core consists of a plate 4 in which is formed a plurality of voids 4a, and this plate 4 is arranged at the interface between the facing external 2 and the

internal facing 3.

  This ventilated plate is, for example, advantageously constituted by a plate made of plastic material such as polypropylene which, in addition to the above-mentioned qualities, has excellent rigidity. Such a plate, known per se, has a thickness of a few millimeters (for example of the order of three millimeters) and it is obtained by an extrusion process, so as to form a plurality of straight channels 4a, for example of quadrangular section, parallel to each other and regularly arranged with respect to each other over the entire

surface of said plate.

  The ventilation channels 4a are separated by thin partitions 4b so that the voids 4a formed in the plate 4 occupy an area greater than 80% by

  relative to the opposite flanges 4c of the plate 4 connected by said partitions (4b).

  Channels 4a remain open at their ends and free to air.

  Considering that composite panels for the above applications are generally rectangular in shape, the ventilation channels

  natural 4a are oriented longitudinally with respect to said panels.

  The different elements 1, 2, 3 and 4 are fixed together by gluing, by

  example using structural adhesives.

  It is understood that, the channels 4a formed in the polypropylene plate remaining open to the air, air circulation is possible in said channels. When the temperature of the external facing increases, the air or natural ventilation circuit causes the temperature of the external facing to drop. The heat reaching the foam core 1 is then considerably reduced and does not affect the condition

  of said foam core which remains rigid.

  In addition, the presence of the cellular polypropylene plate strengthens the mechanical strength of the insulating panel according to the invention, and the acoustic damping required in the production, for example of house roofs. Thermal insulation

  of the whole construction is also reinforced.

Claims (6)

  1. Composite panel, comprising a core disposed between two rigid facings (2, 3), characterized in that said core comprises a relatively thin plate (4) traversed by multiple channels (4a) parallel to each other and regularly distributed, said core being arranged at the interface between the external facing (2) called to receive the sun's rays and the internal facing (3), and assembled to said facing by gluing, preferably at using structural adhesives.   2. Composite panel, according to claim 1, characterized in that the core of the latter also comprises a rigid foam plastic plate (1) disposed between said plate (4) in which is formed   a plurality of channels (4a) and the internal facing (3).   3. Composite panel according to one of claims 1 or 2, characterized in that   that said channels (4a) are executed in a rigid plastic plate, poor heat conductor and having a melting temperature higher than the temperatures resulting from the exposure of the panel to solar radiation.   4. Composite panel according to any one of claims 1 to 3,   characterized in that said channels (4a) are executed in a plate extruded polypropylene.   5. Composite panel according to any one of claims 1 to 4,   characterized in that the channels (4a) are separated by thin partitions (4c) and in that the voids (4a) formed in the plate (4) occupy an area greater than 80% relative to the opposite flanges (4c) of said plate.   6. Composite panel according to any one of claims 1 to 5, adopting a rectangular shape, characterized in that the channels   ventilation (4a) are oriented longitudinally relative to said panel.