METHOD FOR MANUFACTURING AN OPTIMISED INSULATING PANEL, INSULATING PANEL AND INSULATING STRUCTURE COMPRISING SUCH A PANEL

Abstract

The invention relates to a method for manufacturing an insulating panel based on cereal straw, characterized in that it comprises the steps: a) mechanically grinding and sieving the straw to obtain a defibrated straw whose strands have an average length of between 3 mm and 11 mm and whose average diameter is between 0.5 mm and 2.5 mm, b) using a mixer and mixing the defibrated straw with a binder material with a mass proportion of between 3% and 25% and preferably between 4% and 10%, c) injecting compressed air into the mixture to homogenize said mixture, d) heating and calibrating the insulating panel in length and width, e) calibrating the thickness of the material constituting the insulating panel, f) heating the insulating panel to bring it to a temperature of at least 90°C and preferably between 110°C and 150°C, throughout the thickness of said insulating panel and for a period of at least 3 minutes,g) cooling the insulation panel to room temperature, and h) packaging the insulation panel. Figure for abstract: Fig1.,

Description

Title of the invention: METHOD FOR MANUFACTURING AN OPTIMISED INSULATING PANEL, INSULATING PANEL AND INSULATING STRUCTURE COMPRISING SUCH A PANEL Technical field

[0001] The present invention relates to the general technical field of insulating materials used in construction. These insulating materials are generally intended to cover a wall or a roof to provide thermal and sound insulation. These insulating materials, for example in the form of rigid or semi-rigid insulating panels, can also be integrated into prefabricated modular structures made of wood or concrete.

[0002] These insulating materials must also comply with national and / or European standards and have a fire classification.

[0003] It is increasingly requested in the specifications of public or private calls for tender, in France and in other countries, to use bio-sourced insulating materials, with the smallest possible ecological footprint. These insulating materials are, for example, manufactured with renewable and recyclable raw materials, such as wood fibers, cellulose wadding, textile fibers, expanded cork, hemp, sheep's wool or other bio-sourced materials.

[0004] “Bio-sourced materials” means materials derived from renewable organic matter (biomass) of plant or animal origin.

[0005] The invention relates more particularly to the manufacture of such insulating materials in the form of insulating panels. Prior art

[0006] For example, we know the use of cereal straw to insulate a wall or to make such a wall with bales of straw. These must then be associated with elements of the facing type to obtain the regulatory fire resistance, watertightness and airtightness performances. These sub-assemblies generally have wall thicknesses greater than those obtained with non-biosourced insulating materials in order to compensate for their very average or poor thermal conductivity value (lambda - X).

[0007] It should also be noted that most known bio-sourced insulating materials are not suitable or authorized, given their limited fire retardant performance, for buildings with more than three floors.

[0008] The current use of straw as an insulating material has many disadvantages. Among these disadvantages, we can cite the limitation to buildings with three maximum floors, the bulk of the straw bales, the significant generation of dust and debris, the increase in the weight of the structure given the thickness of the insulating material, the need to add non-biosourced materials such as gypsum board or rock wool, is not available as an industrially manufactured mass product. Presentation of the invention

[0009] The object of the invention therefore aims to overcome the drawbacks of the prior art by proposing a new method for manufacturing insulating panels from an ecological, renewable, recyclable raw material available in almost all rural areas.

[0010] Another object of the invention is to propose a method for manufacturing insulating panels, which is easy to implement and economical.

[0011] Another object of the invention is to provide insulating panels having excellent fire retardant, thermal insulation and sound insulation performance.

[0012] Another object of the invention is to provide insulating panels having sufficient properties and performance to allow their use in buildings comprising more than three floors.

[0013] Another object of the invention is to provide prefabricated insulating modular elements, having excellent fire retardant and thermal and sound insulation performance.

[0014] The objects assigned to the invention are achieved using a method of manufacturing an insulating panel based on cereal straw, characterized in that it comprises the steps: a) mechanically crushing the straw to obtain a defibrated straw whose strands have an average length of between 3 mm and 22 mm and preferably between 3 mm and 11 mm and whose average diameter is between 0.5 mm and 4.0 mm and preferably between 0.5 mm and 2.5 mm, b) using a mixer and mixing the defibrated straw with a binder material introduced into the mixer with a mass proportion of between 3% and 25% and preferably between 4% and 10% relative to the total mass of the mixture, c) injecting compressed air into the mixture to homogenize the said mixture, d) heating and calibrating the mixture in length and width, e) calibrate the thickness of the mixture to form the insulating panel, f) continuing to heat the mixture or the insulating panel to bring it to or maintain it at a temperature of at least 90°C and preferably between 110°C and 150°C, throughout the thickness of said insulating panel for a period of at least 3 minutes, (g) cooling the insulation panel to room temperature or near room temperature, and h) pack the insulation panel.

[0015] According to an exemplary implementation, the method consists in step a) of using at least one grinder to shred and grind the straw into bales, said at least one grinder comprising adjustable shredding / grinding tools to define the shape and size properties of the strands of defibrated straw obtained, said tools comprising knives and hammers in series.

[0016] According to an exemplary implementation, the method consists, in steps b), c) and d), of using at least one mixer of the rotating cylinder type, associated downstream with a drop cage and heating the mixture in said drop cage.

[0017] According to an exemplary implementation, the method consists of filtering the defibrated straw obtained under a) to remove dust and other impurities in a proportion by mass of at least 2% and preferably at least 5% to 10% of the defibrated straw.

[0018] According to an exemplary implementation, the method consists in step e) of exerting linear pressure on the insulating panel being formed, by means of a compression roller.

[0019] Alternatively, it is possible to use pressure strips, a mold or a stainless steel mesh to carry out the thickness calibration of the insulating panel.

[0020] By way of example, the binder material comprises a two-component thermofusible binder chosen from two-components comprising polylactic biopolymer fibers of the PLA / Co-PLA, PLA / PBS type obtained from cereals.

[0021] According to another example, the binder material comprises a two-component hot-melt binder comprising Polyester / Polyethylene, Polyester / PBT fibers.

[0022] According to an exemplary implementation, the method consists of mixing the binder material, or the mixture of defibrated straw and the binder material, with one or more adjuvants comprising a fungicidal product with a proportion by mass relative to the total mass of the mixed products, of between 1% and 11%.

[0023] For example, the adjuvants comprise a fire retardant product with a proportion by mass relative to the total mass of the mixed products, of between 24% and 72%.

[0024] For example, the fire-retardant product is chosen from geo-sourced products.

[0025] According to one example, the fire retardant product is in viscous or liquid form and comprises a geopolymer of the metakaolin type.

[0026] According to an exemplary implementation, the method comprises an operation of disentangling and aerating the binding material prior to step b).

[0027] According to an exemplary implementation, the method comprises a step of applying to at least one face of the insulating panel, a fire-retardant or flame-retardant coating, which has a thickness of at least 0.5 mm.

[0028] The objects assigned to the invention are also achieved with an insulating panel comprising a first panel obtained by the manufacturing method as presented above and on which an additional fire-retardant panel is glued.

[0029] The objects assigned to the invention are also achieved with an insulating panel comprising a first panel obtained by the manufacturing process as presented above, and on which is glued an additional fire-retardant panel, the additional panel also being obtained by the manufacturing process as presented above, with a fire-retardant product having a proportion by mass relative to the total mass of the mixed products greater than 49%.

[0030] The objects assigned to the invention are also achieved with a prefabricated modular structure made of wood or mixed concrete-wood for making a wall or a partition or for covering a wall of a building, on the exterior side or the interior side, characterized in that it comprises at least one insulating panel manufactured according to the method as presented above.

[0031] The manufacturing process according to the invention provides the remarkable advantage that the insulating panels obtained have a very high homogeneity throughout their entire thickness. The process according to the invention in fact makes it possible to heat the core of the insulating panels sufficiently to obtain complete and homogeneous polymerization throughout the entire thickness of said insulating panels. This makes it possible to improve their performance in terms of thermal and sound insulation of said panel as well as the strength of said panels over time.

[0032] Another advantage of the process according to the invention lies in obtaining insulating panels whose fire reaction classification allows them to be adapted to meet the various standards and legislation in force.

[0033] The insulating panels obtained using the process according to the invention also exhibit remarkable performance. Indeed, these panels have a lambda-X thermal conductivity coefficient of 0.038, which is remarkable, knowing that the thermal conduction coefficient is between 0.052 and 0.080 for straw, between 0.037 and 0.044 for expanded cork and between 0.037 and 0.042 for cellulose wadding.

[0034] The method according to the invention makes it possible to obtain insulating panels whose handling and storage are greatly facilitated. The insulating panels have in fact a reduced weight and size compared in particular to bales of straw. Brief description of the figures

[0035] Other characteristics and advantages of the present invention will appear more clearly on reading the description which follows, given with reference to the appended drawing, given by way of non-limiting example, in which:

[0036] [Fig-1] [Fig.l] is a schematic view of a flowchart of an example of implementation implementation of the manufacturing process in accordance with the invention,

[0037] [Fig.2] [Fig.2] is a schematic view of a flowchart of another example of implementation of the manufacturing process in accordance with the invention,

[0038] [Fig.3] [Fig.3] is a schematic view of a flowchart of a variant of the implementation example illustrated in [Fig.2],

[0039] [Fig.4] [Fig.4] a schematic view of a flowchart of an additional example implementation of the manufacturing process in accordance with the invention, and

[0040] [Fig.5] [Fig.5] a schematic view of a flowchart of another additional example of implementation of the manufacturing method according to the invention. Detailed description of the invention

[0041] Structurally and functionally identical elements present in several distinct figures are assigned the same numerical or alphanumeric reference.

[0042] [Fig.l] is an illustration of an example of an installation making it possible to implement the process for manufacturing insulating panels from cereal straw, such as wheat, barley, oats, rapeseed, miscanthus, rice straw or various mixtures thereof.

[0043] The installation comprises a grinding unit 1 for transforming raw straw into defibrated straw by shredding and grinding.

[0044] The grinding and defibering unit 1 advantageously comprises tools for cutting and splitting the straw strands. For example, the grinding and defibering unit 1 comprises two grinders connected in series. The first grinder comprises, for example, tools for cutting the straw strands, such as knives. The second grinder comprises, for example, tools for splitting the straw strands, such as hammers.

[0045] By defibrated straw is meant a straw comprising cut and split strands of average length between 3 mm and 22 mm and whose average diameter is between 0.5 mm and 4.0 mm. Preferably, the defibrated straw strands have an average length between 3 mm and 11 mm and an average diameter between 0.5 mm and 2.5 mm.

[0046] The average diameter must be understood as being the largest dimension of the straw strand, taken in a plane orthogonal to the longitudinal direction of said strand. For example, a defibrated straw comprises from 29% to 33% of strands having a average length of 9.633 mm with an average diameter greater than 2 mm, 32% to 37% of strands having an average length of 6.951 mm with an average diameter greater than 1 mm and 16% to 20% of strands having an average length of 3.960 mm with an average diameter greater than 0.5 mm.

[0047] The remainder of this sampling is considered to be dust, which is preferably removed by filtration using a filtration / dosing unit 2

[0048] [Fig.l] illustrates, using a flowchart, an example of implementation of a method for manufacturing a loose insulating material from cereal straw, such as wheat, barley, oats, rapeseed, miscanthus, rice straw or various mixtures thereof.

[0049] The installation comprises a grinding and defibering unit 1 for transforming raw straw into defibered straw by shredding and grinding.

[0050] By defibrated straw, it is preferably appropriate to understand a straw comprising non-homogeneous strands, of average length between 3 mm and 11 mm and whose average diameter is between 0.5 mm and 2.5 mm.

[0051] The average diameter must be understood as being the largest dimension of the straw strand, taken in a plane orthogonal to the longitudinal direction of said strand.

[0052] For example, a defibrated straw comprises from 29% to 33% of strands having an average length of 9.633 mm with an average diameter greater than 2 mm, from 32% to 37% of strands having an average length of 6.951 mm with an average diameter greater than 1 mm and from 16% to 20% of strands having an average length of 3.960 mm with an average diameter greater than 0.5 mm.

[0053] The remainder of this sample example is considered to be dust, which is preferably removed by filtration using a filtration / dosing unit 2.

[0054] The method is for example implemented using an installation illustrated schematically with the flowchart of [Fig.l].

[0055] The installation comprises a grinding / shredding unit 1 fed with straw, for example packaged in bales. The grinding / shredding unit 1 comprises, for example, two grinders in series, which may comprise grinding tools having specific shapes or settings.

[0056] The grinders advantageously include adjustable shredding / grinding tools to define the shape and size parameters of the strands of the defibrated straw.

[0057] According to another embodiment of the installation, the crushing and defibration unit 1 comprises knives for cutting the straw strands and hammers for splitting said strands. In the context of the implementation of the shredding and crushing of the straw, one or more passages may be provided in the crushing and defibration unit. defibration 1. The number of passes depends on the morphology (shape, length and diameter) sought for the defibrated straw strands. This produces defibrated straw, at the outlet of the grinding and defibration unit 1, composed of dimensionally and shaped optimized strands, to promote their mixing with a binding material on the one hand and to improve the thermal insulation, sound insulation and mechanical properties of the solid insulating material obtained on the other hand.

[0058] According to an exemplary embodiment, the installation also comprises a filtering and dosing unit 2 which directly feeds a mixer 3.

[0059] The filtering operation is carried out for example by using, for example, a vibrating screen and / or using a cyclonic separator. The latter can advantageously be used to transfer the defibrated straw to the mixer 3. Filtering makes it possible to separate the defibrated straw from dust and other impurities by gravity or by cyclonic filtering.

[0060] The mixer 3 comprises, for example, at least one mixer of the rotating cylinder type associated downstream with a drop cage.

[0061] The installation also comprises a first dosing and spraying unit 4a for supplying the mixer 3 with adjuvants. The latter comprise at least one fungicidal adjuvant F. These adjuvants may also comprise a fire-retardant adjuvant R.

[0062] The installation also comprises a second dosing and spraying unit 4b for supplying the mixer 3 with the binder material.

[0063] The installation advantageously comprises a disentangling and aeration unit 5 for decompacting the binder material before its metering and spraying in the mixer 3. The disentangling and aeration unit 5 comprises for example a carding system so as to separate the constituent fibers of the binder material.

[0064] The installation also comprises a compressor 6 for injecting compressed air into the mixer 3, thus promoting the homogenization and aeration of the mixture.

[0065] The installation also comprises a unit 7 for formatting and calibrating the insulating material at the outlet of the mixer 3. This formatting and calibrating unit 7 makes it possible, for example by molding, to produce the shape in dimensions and thickness of the insulating panel.

[0066] The installation also comprises a heating unit 8 for heating the mixture and / or the insulating panel throughout its thickness and thus obtaining the crosslinking of the binding material and consequently the stiffening of said insulating panel.

[0067] The installation also comprises a cooling unit 9 for the insulating panel at the outlet of the heating unit. This cooling unit 9 may consist, for example, of an ambient air conveyor, bringing the insulating panel to a packaging unit 10. The cooling unit 9 may also include an intermediate storage area, for the time necessary for cooling the insulating panel.

[0068] [Fig.2] is a schematic view of a flowchart of another example of implementation implementation of the insulating panel manufacturing process. The installation for this purpose comprises a bonding unit 11, which allows, downstream of the cooling unit 9, to bond an additional rigid fire-retardant panel to the stiffened insulating panel. This additional panel is for example made with known materials, for example based on plaster or others.

[0069] According to another example of implementation of the method, the additional panel is also obtained by the manufacturing method according to the invention. The fire-retardant product then advantageously has a proportion by mass relative to the total mass of the mixed products greater than 49%. This additional panel then has a greater density and a smaller thickness than the first stiffened insulating panel. This gives an assembly having excellent thermal and sound insulation properties as well as good fire-retardant performance.

[0070] [Fig. 3] is a schematic view of a flowchart of another example of implementation of the method for manufacturing the insulating panel. The installation comprises for this purpose an application unit 12, which allows, downstream of the cooling unit 9, to coat the stiffened insulating panel with a fire-retardant or flame-retardant coating. This coating is for example produced with a known fire-retardant product.

[0071] The insulating panel is then placed in a drying unit 13 before being conveyed to the packaging unit 10.

[0072] [Fig.4] is a flowchart illustrating an additional example of implementation of the manufacturing method according to the invention. For this purpose, the installation for implementing the method comprises a complementary mixing and heating unit 7a at the outlet of the mixer 3. The complementary mixing and heating unit 7a advantageously comprises a drop cage into which air preheated to a temperature between 90°C and 150°C is injected. At least partial fusion of the thermofusible bi-component fibers is thus obtained during this complementary mixing operation.

[0073] According to another example of implementation, it is possible to use infrared lamps and / or air heated by electrical resistors to heat the mixture in the drop cage.

[0074] Downstream of the drop cage, the installation comprises a calibration and heating unit 8a in the form of a heating mold, into which the mixture from said drop cage is transferred by gravity or by conveying. The heating operation is continues during the calibration of the shape and thickness of the insulating panel before the cooling operation. This heating, continuing during the forming / molding / calibration phase of the mixture, allows the temperature to be maintained and therefore optimal crosslinking of the binding material to be obtained.

[0075] Alternatively, step f) is carried out using a system producing heated air, which is injected under pressure into the formed insulating panel.

[0076] Heating the mixture allows the crosslinking of the binder material to occur, which then forms a rigid three-dimensional network in which the strands of defibrated straw and the fibers of the binder material are bound together. Due to the cut and split configuration of the strands of defibrated straw, the latter are also mechanically fixed in said rigid network of crosslinked binder material.

[0077] [Fig. 5] a schematic view of a flowchart of another additional example of implementation of the manufacturing method according to the invention. In this example of implementation, the installation comprises in series a first mixer 3a and a second mixer 3b.

[0078] The defibrated straw, at the outlet of the filtration and dosing unit 2, is conveyed into the first mixer 3a, as is the binding material at the outlet of the second dosing and spraying unit 4b.

[0079] Depending on specific characteristics sought for the insulating panel, a mixture A prepared in the first mixer 3a, with the addition where appropriate of a fungicidal adjuvant F, is conveyed to the formatting and calibration unit 7 (arrow A).

[0080] Depending on other specific characteristics sought for the insulating panel, the mixture A prepared in the first mixer 3a, with the addition where appropriate of a fungicidal adjuvant F, is conveyed to the second mixer 3b (arrow B). A complementary spray dosing unit 4c can then inject a fire-retardant adjuvant R into the second mixer 3b. This produces a mixture B which will be conveyed to the final formatting and calibration unit 7. The mixture B will then lead to the production of an insulating panel having more or less marked “fire-retardant” properties, depending on the nature and the proportion by mass of the fire-retardant adjuvant used.

[0081] The insulating material in the form of a panel is therefore manufactured according to the manufacturing method in accordance with the invention and detailed below.

[0082] The method for manufacturing the insulating material based on cereal straw comprises a step a) consisting of mechanically grinding the straw to obtain a defibrated straw whose strands preferably have an average length of between 3 mm and 11 mm and whose average diameter is between 0.5 mm and 2.5 mm.

[0083] Advantageously, the process consists of filtering the defibrated straw obtained under a) to remove dust and other impurities in a proportion by mass of at least 2% and preferably 5% to 10% of the defibrated straw. The separation of unwanted residues and dust or other materials affecting the performance of the insulating material can therefore be done by gravity using a sieve, for example a vibrating sieve or using cyclonic filtration. This filtration and separation advantageously reduces the risk of explosion, linked to the concentration of dust in the air on manufacturing sites.

[0084] According to a step b) the mixer 3 is used and the defibrated straw is mixed with a binder material, introduced into the mixer 3 for example by spraying, with a mass proportion of between 3% and 25% and preferably between 4% and 10% relative to the total mass of the mixture.

[0085] According to an advantageous example of implementation, the method comprises an operation of disentangling and aeration of the two-component binder material prior to step b). This preparation of the material comprises, for example, a carding operation. This disentangling and aeration phase can, for example, be carried out separately or directly in the mixer 3 before the introduction of the binder material.

[0086] The defibrated straw is then introduced in turn into the mixer 3 after the binding material.

[0087] According to step c), compressed air is injected into the mixer 3a and, if necessary, into the mixer 3b to homogenize said mixture.

[0088] Then, according to a step d), the mixture is heated and calibrated to give it the desired length and width. The heating phase advantageously begins in the drop cage. The length and width calibration of the mixture / insulating panel is advantageously done in a mold or template.

[0089] Heating the mixture in the drop cage makes it possible to obtain an expansion of the mixture, that is to say an increase in its volume, promoting the diffusion of hot air throughout the mixture.

[0090] According to a following step e), the mixture is calibrated in thickness. For example, linear pressure is exerted on the insulating panel being formed, by means of a compression roller to carry out the thickness calibration.

[0091] According to step f), the mixture or the insulating panel is continued to be heated in a mold or template to bring it to or maintain it at a temperature of at least 90°C and preferably between 110°C and 150°C, throughout the thickness of said insulating panel for a period of at least 3 minutes.

[0092] Then, according to a step g), the insulating panel is cooled to room temperature or to a temperature close to room temperature.

[0093] Finally, according to step h), the insulating panel is packaged.

[0094] According to another example of implementation of steps d), e) and f), the following is carried out: prior to the heating phase, the calibration in length, width and thickness of the mixture, to form, preferably in a mold or template, the insulating panel. Hot air is then injected under pressure into the already formed insulating panel to achieve crosslinking of the binding material.

[0095] The duration of the mixing operation(s) depends on the size of the installation and in particular of the mixer 3.

[0096] According to an exemplary implementation, the method consists in step a), of using at least one grinder to shred and grind the straw into bales, said at least one grinder comprising adjustable shredding / grinding tools to define the shape and dimensional properties of the strands of defibrated straw obtained.

[0097] The mixers 3, 3a and 3b are advantageously rotating cylinders followed downstream by a drop cage.

[0098] According to an exemplary implementation, the binder material comprises a binder comprising thermofusible bi-component fibers, Polyester / Polyethylene fibers, Polyester / PBT fibers. These thermofusible bi-component fibers advantageously have a low melting point of approximately 110°C.

[0099] According to another example of implementation, the binder material comprises polylactic biopolymer fibers of the PLA / Co-PLA, PLA / PBS type obtained from cereals. These thermofusible bi-component fibers advantageously have a low melting point between 130°C and 164°C.

[0100] According to an exemplary implementation, the method consists of mixing the binder material, or the mixture of defibrated straw and the binder material, with one or more adjuvants comprising a fungicidal product with a proportion by mass relative to the total mass of the mixed products, of between 1% and 11%.

[0101] According to another example of implementation, the adjuvants comprise a fire-retardant product with a proportion by mass relative to the total mass of the mixed products, of between 24% and 72%.

[0102] According to another example of implementation, the fire-retardant product comprises a geopolymer in viscous or liquid form. By way of example, mention may be made of meta-takaolin.

[0103] According to an exemplary implementation, the method comprises a step of applying to at least one face of the insulating panel, a fire-retardant or flame-retardant coating, which has a thickness of at least 0.5 mm.

[0104] The invention also relates to a composite insulating panel comprising an insulating panel obtained according to the manufacturing method detailed above and onto which an additional fire-retardant panel is bonded.

[0105] The invention also relates to a prefabricated modular wooden structure for making a wall or a partition or for covering a wall of a building, on the exterior or interior side. Such a structure comprises at least one insulating panel obtained according to the manufacturing process detailed above.

[0106] The invention also relates to a mixed prefabricated modular structure made of wood and concrete for making a wall or a wall or for covering a wall of a building, on the exterior or interior side. Such a structure comprises at least one insulating panel obtained according to the manufacturing method detailed above.

[0107] By way of example, the method according to the invention makes it possible to manufacture a semi-rigid insulating panel having a density of between 50 kg / m3 and 70 kg / m3 after cooling.

[0108] It is obvious that the present description is not limited to the examples explicitly described, but also includes other embodiments and implementations. Thus, a described technical characteristic, or a described method step, can be replaced by an equivalent technical characteristic, respectively an equivalent step, without departing from the scope of the present invention as defined by the claims.

Claims

Claims

1. A method of manufacturing an insulating panel based on cereal straw, characterized in that it comprises the steps: a) mechanically grinding the straw to obtain a defibrated straw whose strands have an average length of between 3 mm and 22 mm and preferably between 3 mm and 11 mm and whose average diameter is between 0.5 mm and 4.0 mm and preferably between 0.5 mm and 2.5 mm, b) using a mixer (3) and mixing the defibrated straw with a binder material introduced into the mixer (3) with a mass proportion of between 3% and 25% and preferably between 4% and 10% relative to the total mass of the mixture, c) injecting compressed air into the mixture to homogenize said mixture, d) heating and calibrating the mixture in length and width, e) calibrating the mixture in thickness to form the insulating panel,f) continuing to heat the mixture or the insulating panel to bring it to or maintain a temperature of at least 90°C and preferably between 110°C and 150°C, throughout the thickness of said insulating panel for a period of at least 3 minutes, g) cooling the insulating panel to room temperature or close to room temperature, and h) packaging the insulating panel.,

2. Method according to claim 1, characterized in that it consists in step a) of using at least one grinder to shred and grind the straw into bales, said at least one grinder comprising adjustable shredding / grinding tools to define the shape and size properties of the strands of defibrated straw obtained, said tools comprising knives and hammers in series.

3. Method according to claim 1 or 2, characterized in that it consists, under steps b), c) and d), in using at least one mixer (3) of the rotating cylinder type, associated downstream, with a drop cage and heating the mixture in said drop cage.

4. Method according to any one of claims 1 to 3, characterized in that it consists of filtering the defibrated straw obtained under a) to remove dust and other impurities in a proportion by mass of at least 2% and preferably at least 5% to 10% of the straw. defibrated.

5. Method according to any one of claims 1 to 4, characterized in that it consists in step e) of exerting linear pressure on the insulating panel in formation, by means of a compression roller, pressure bands, a mold or a stainless steel mesh, to carry out the thickness calibration.

6. Method according to any one of claims 1 to 5, characterized in that the binder material comprises a thermofusible two-component binder chosen from two-components comprising polylactic biopolymer fibers of the PLA / Co-PLA, PLA / PBS type obtained from cereals.

7. Method according to any one of claims 1 to 5, characterized in that the binder material comprises a two-component hot-melt binder comprising Polyester / Polyethylene, Polyester / PBT fibers.

8. Method according to any one of claims 1 to 7, characterized in that it consists of mixing the binder material, or the mixture of defibrated straw and the binder material, with one or more adjuvants comprising a fungicidal product with a proportion by mass relative to the total mass of the mixed products, of between 1% and 11%.

9. Method according to claim 8, characterized in that the adjuvants comprise a fire retardant product with a proportion by mass relative to the total mass of the mixed products, of between 24% and 72%.

10. Method according to claim 9, characterized in that the fire-retardant product is chosen from products from a family of geosourced products.

11. A method according to claim 9 or 10, characterized in that the fire-retardant product is in viscous or liquid form and comprises a geopolymer of the metakaolin type.

12. Method according to claim 6 or 7, characterized in that it comprises an operation of disentangling and aeration of the binding material prior to step b).

13. Method according to any one of claims 1 to 12, characterized in that it comprises a step of applying to at least one face of the insulating panel, a fire-retardant or flame-retardant coating, which has a thickness of at least 0.5 mm.

14. Composite insulating panel comprising a first panel obtained by the manufacturing method according to any one of claims 1 to 12, and on which an additional fire-retardant panel is glued.

15. Insulating panel comprising a first panel obtained by the manufacturing method according to any one of claims 1 to 12, and on which is glued an additional fire-retardant panel, which additional panel is also obtained by the manufacturing method according to any one of claims 1 to 12 with a fire-retardant product having a proportion by mass relative to the total mass of the mixed products greater than 49%.

16. Prefabricated modular structure made of wood or mixed concrete-wood for making a wall or for covering a wall of a building, on the exterior or interior side, characterized in that it comprises at least one insulating panel manufactured according to the method according to any one of claims 1 to 13.

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