thermal insulating element.

Abstract

Thermal insulation element comprising: a thermal insulation panel; a continuous peripheral vapor barrier layer. The continuous peripheral layer completely encases the insulation panel. This element allows the creation of removable insulation systems.

Description

Title of the invention: thermal insulating element.

[0001] The invention relates to a thermal insulating element. It also relates to a method for thermally insulating flat surfaces such as attic floors.

[0002] In the context of sustainable development, energy savings are becoming increasingly important. Energy consumption for heating buildings, particularly residential buildings, constitutes a significant share (for example, more than 20% in France) of total energy consumption. Improving the thermal insulation of buildings is therefore essential.

[0003] It is known that thermally insulating materials must be protected from water vapor to avoid possible condensation of the latter within them. This problem is typically solved by placing a membrane called a "vapor barrier" or "vapor brake" on the warm side of the insulation. In countries with a cold to temperate climate this warm side is inside the building.

[0004] For example, in the case of temporary buildings or those under construction, or simply to allow certain inspections or modifications, the inventors believe that there should also be an interest in removable and recyclable insulating systems as such, which can be moved and reused.

[0005] US6279284 describes a composite thermal insulation panel comprising a vapor barrier membrane. This panel is however intended to be permanently inserted, for example, into a metal structure ("stud"). Its dismantling is accompanied by partial destruction of the panel since the latter includes the supporting structure of the wall.

[0006] The invention aims to provide an insulating element having good protection against water vapor while allowing its non-destructive disassembly.

[0007] Accordingly, the invention relates to a thermal insulating element comprising: • a thermal insulation panel; • a peripheral vapor barrier layer.

[0008] This element is characterized in that the peripheral vapor barrier layer is continuous and completely encases the insulating panel.

[0009] The thermal insulation panel has an approximately parallelepiped shape. Its surface area depends on the applications but typically varies between 0 and 4 m2. It is often greater than 0.25 m2, frequently greater than 0.5 m2. In general it is less than 3 m2, often less than 2 m2. The thickness of the panel is commonly between 1 and 40 cm, with thicknesses between 5 and 20 cm being the most frequent.

[0010] The thermal insulation panel comprises at least 50% by volume of insulation thermal, preferably more than 75% and advantageously more than 80% or even more than 85% or 90%. Thermal insulation panels consisting essentially of thermal insulation are frequently used. Thermal insulation is understood to mean a material whose thermal conductivity is less than 0.1 W / m°K, preferably less than 0.05 W / m°K. Examples of such well-known materials are wood wool, hemp, glass or rock wool, expanded polystyrene, polyurethane foam.

[0011] According to the invention, the insulating element comprises a peripheral vapor barrier layer. This is intended to prevent water vapor from penetrating into the thermal insulation panel and condensing there. This layer preferably has a water vapor diffusion resistance (value "Sd") greater than 0.1 m, advantageously greater than 0.5 m, preferably greater than 1 m. This value expresses the thickness of a fictitious air layer with the same diffusion resistance. It is measured according to DIN 52615.

[0012] In the insulating element according to the invention, the peripheral vapor barrier layer is continuous and completely encases the insulating panel. This means that the outer surface of the insulating panel is entirely covered by the vapor barrier layer. In addition to the two main faces of the parallelepiped, its edges are therefore also covered by the vapor barrier layer. It should be noted that this fact makes it possible to use vapor barrier layers having Sd parameters higher than the maximum values ​​generally recommended (higher than 5 or even 10 μm). Such maximum values ​​are in fact generally intended to allow the evacuation of condensed vapor which may have accidentally penetrated the thermal insulation. Complete encasement, especially if carried out in the factory, makes it possible to avoid this risk.

[0013] It may be advantageous for the continuous vapor barrier layer to include a reinforcement, made of fibers providing this layer with the desired mechanical properties. These fibers can be of any length, well known to those skilled in the art. The use of continuous fibers made of ultra-high molecular weight polyethylene makes it possible to obtain elements with exceptional mechanical properties. Such insulating elements then become structural load-bearing elements, which can even be painted if necessary to meet aesthetic needs.

[0014] The continuous peripheral vapor barrier layer may consist of a pre-existing solid film which is applied to the insulating panel. This pre-existing film is preferably provided with a reinforcement. To obtain the coating from a flat film, the continuous layer must include junctions which are made in a sealed manner, with the necessary overlaps. Sealing at the junctions may be obtained by gluing, by using adhesive strips, but preferably by welding the edges of the junctions.

[0015] In this embodiment, it may be advantageous to assemble two different films on the main faces of the insulating panel, the two films having different values ​​of the parameter Sd. This variant allows, for example, one of the faces of the element to temporarily resist rain or permanently resist possible roof infiltrations (rain shield function).

[0016] In another embodiment of the invention, which is recommended, the continuous vapor barrier layer comprises a polymer and is monolithic. Monolithic is understood to mean a layer which does not comprise junctions. Such a layer can be obtained by applying a polymer, having the desired vapor barrier properties, in a pasty state to the panels, for example by spraying or by immersing the panels in a bath of the polymer in a pasty state. It is recommended that the continuous vapor barrier layer comprise at least 50% by volume, preferably at least 75%, of the polymer. The paste can be obtained by dissolving the polymer or by melting it when the polymer has a low melting point. Polymers of the polycaprolactone family, for example, have melting temperatures significantly lower than 100°C. After cooling or evaporation of the solvent, the monolithic continuous layer is obtained.In this recommended embodiment of the invention, if reinforcement is desired, it can be applied, in the form of continuous fibers, by winding around the panel, before the application of the polymer paste.

[0017] In a variant of the invention, the insulating panel comprises at least 75% by volume of a moisture-sensitive insulating material. Moisture-sensitive thermal insulating materials are understood to mean materials such as, for example, wood wool, hemp, straw, but also glass or rock wool. These materials tend to absorb moisture and if this happens, they lose a significant part of their insulating properties or even deteriorate.

[0018] In this advantageous embodiment, the use of so-called natural insulating materials such as wood wool, hemp, and straw is recommended. Wood wool, for example, has low thermal conductivity but also good specific heat, which allows it to improve the thermal inertia of buildings. In addition, not only does its production emit little CO2, but it also allows it to be stored.

[0019] Natural insulating materials are advantageously biodegradable.

[0020] In the embodiments of the invention using a moisture-sensitive insulating material, and especially those known as natural, the insulating material generally has a density greater than 25 kg / m3, preferably greater than 30 kg / m3, more preferably 35 kg / m3. Insulating materials with a density greater than 40 kg / m3, or even greater than 45 kg / m3 or even greater than 50 kg / m3 are the most advantageous.

[0021] In an embodiment of the invention which is particularly advantageous when the insulating material is biodegradable and preferably selected from wood, hemp or straw, the continuous vapor barrier layer is also biodegradable. The biodegradability is evaluated for example with the standards ISO 14851 or ISO 14855. It is recommended that the biodegradability of the continuous vapor barrier layer be of the same order of magnitude as that of the insulating material.

[0022] In a variant of this latter embodiment, the biodegradable continuous vapor barrier layer comprises starch or cellulose. Polymers such as cellulose acetate or other cellulose derivatives are assimilated to cellulose. In this variant, the vapor barrier layer comprises more than 10% by weight of starch or cellulose, generally more than 25%, often more than 40%. The starch is preferably thermoplastic, that is to say it comprises a plasticizer such as glycerol. It is recommended that the continuous vapor barrier layer comprises a mixture of polymers such as polycaprolactone and starch or lactic acid and starch. The combination of thermoplastic starch and polyethylene, when thermoplastic starch is the continuous phase, are also advantageous, combining biodegradability and barrier properties.Ternary blends comprising thermoplastic starch, cellulose (e.g., in the form of fibers), and another polymer (e.g., polycaprolactone or polyethylene) are known for their combinations of interesting properties. When high biodegradability is desired, it is recommended that polymer blends have co-continuous phases.

[0023] In their practical applications, the elements according to the invention must be combined to cover sufficient surfaces. It is important that the various combined elements are in close contact to avoid losses of insulation by air convection between the elements. To this end, it is recommended that the elements be combined by compression, that is to say that a holding structure, such as an external frame, into which the elements are introduced, keeps them clamped. The density and thickness of the insulating panels used must enable them to withstand the compression forces necessary to obtain sufficient airtightness for practical thermal insulation needs.

[0024] It may happen that the building naturally includes such a structure. This may be walls or the supporting structure of a roof. In general, a simple structure is preferably constructed. In general, it is recommended that the supporting structure have a surface area of ​​between 90 and 95% of the cumulative surface area of ​​the elements it supports, to obtain adequate compressive forces and the necessary close contact.

[0025] The invention therefore also relates to a thermal insulation system comprising a set of elements in accordance with the invention, assembled side by side, and a rigid compression-supported structure, capable of keeping the various elements of the assembly in close contact with each other.

[0026] As indicated above, by close contact is meant that the compressive forces of the elements between them, edge against edge, are sufficient to avoid convective movements of air.

[0027] In cases where the panels cannot sufficiently withstand these forces, for example if they have too low a density, it is certainly possible to supplement or cause the elements to remain in contact with each other by means of adhesive strips applied to the perimeters of the elements, the strip overlapping two contiguous elements. It will then be possible to preferably choose strips whose adhesive power is not too great to be able to be removed without damaging the vapor barrier layer of the element.

[0028] The invention also relates to a method for producing an element, the continuous vapor barrier layer of which comprises a polymer and is monolithic, according to which the polymer is applied in a pasty state to the insulating panel and then solidified. The pasty polymer can be sprayed or coated onto the insulating panel. The insulating panel can also be immersed in a bath of the polymer, which is in a pasty state. If the paste is obtained by heating the polymer, solidification is simply achieved by cooling. The softening temperature of the polymer must be compatible with the thermal resistance of the panels. In general, this temperature is less than 100°C. If the paste is obtained by dissolving the polymer in a solvent, solidification results from the evaporation of the latter.

[0029] The invention also relates to a method for thermally insulating a wall according to which a system according to the invention is arranged against the wall. The method according to the invention is particularly advantageous for insulating horizontal walls, such as attic floors, for example.

[0030] The elements, system and method according to the invention allow disassembly without damage to the insulating structure, which allows its complete and integral reuse.

[0031] The invention therefore finally relates to a method for successively insulating at least two walls according to which: • a set of elements according to the invention are assembled to form a first system according to the invention and said system is arranged against a first wall, • the system is removed from the wall and the elements disassembled, • the said elements are reassembled to form a second system • the second system is placed against a second wall.

[0032] This process can be continued several times.

[0033] Example

[0034] A set of 24 wood fiber insulation panels, each 135 cm long, 57 cm wide and 14 cm thick and having a thermal conductivity of 0.036 W / °Km, are coated with a 0.2 mm thick polyethylene vapor barrier film. The joints are sealed by folding and hot air welding. During this operation, the 6 faces (including 4 edges) of the insulation panels are carefully covered with the vapor barrier film. This results in 24 insulating elements. A rectangular frame with internal dimensions of 385 cm X 435 cm is constructed inside a temporarily unused attic room using fir beams with a thickness of 5 cm and a height of 15 cm. This frame essentially covers the entire floor area of ​​the room.All 24 insulating elements are inserted into the frame (3X8), placing the elements side by side, so that the frame, whose inner surface is slightly less than the cumulative surface area of ​​the elements, compresses them against each other to avoid air convection between the panels.

[0035] When a technical operation must be carried out in the room, certain elements are removed from the frame and then put back in place at the end of the technical operation.

Claims

Claims

1. Thermal insulating element comprising: • a thermal insulating panel, • a peripheral vapor barrier layer, characterized in that the peripheral vapor barrier layer is continuous and completely encases the insulating panel.

2. An element according to the preceding claim wherein the continuous peripheral layer comprises a polymer and is monolithic.

3. An element according to the preceding claim wherein the continuous peripheral vapor barrier layer is biodegradable and comprises starch or cellulose.

4. An element according to any preceding claim wherein the insulating panel comprises at least 75% by volume of a moisture-sensitive insulating material selected from wood wool, straw, hemp or wool.

5. Element according to one of the preceding claims in which the continuous peripheral vapor barrier layer has an Sd value greater than 0.1m.

6. Element according to one of the preceding claims in which the continuous peripheral layer has different Sd values ​​on the two main faces of the insulating panel.

7. A method for producing an element according to claim 2 and claims 3 to 6 dependent thereon, wherein the polymer is applied in a pasty state to the insulating panel and then solidified.

8. Thermal insulation system comprising a set of elements according to claims 1 to 6, assembled side by side, and a rigid compression-supporting structure, capable of maintaining the different elements of the set in close contact with each other.

9. A method for thermally insulating a wall wherein a system according to claim 8 is disposed against the wall.

10. Method for successively insulating at least two walls according to which: • a set of elements in accordance with one of claims 1 to 6 are assembled to form a first system according to claim 8 and said system is arranged against a first wall, the system is removed from the wall and the elements disassembled, said elements are reassembled to form a second system the second system is placed against a second wall.