Bio-sourced fibrous sheet with insulating properties

Abstract

The present invention relates to a fibrous web comprising byssus fibers, a ready-to-cook mixture for producing this fibrous web, a method for manufacturing the ready-to-cook mixture and a use of the fibrous web as an insulating and / or fireproofing material.

Description

Title of the invention: Bio-sourced fibrous sheet with insulating properties Field of invention

[0001] The present invention relates to a fibrous web comprising byssus fibers, a ready-to-cook mixture for producing this fibrous web, a method for manufacturing the ready-to-cook mixture and a use of the fibrous web as an insulating and / or fireproofing material. State of the art

[0002] Byssus fibers are biopolymer fibers produced by mussels. Byssus fibers are produced by the mussel's foot and allow the mussel to move and cling to submerged or partially submerged supports. Byssus fibers thus have the advantages of their ability to remain adherent to hard surfaces in aquatic habitats and high strength and extensibility to resist wave forces.

[0003] Byssus fibers are composed mainly of proteins: collagen proteins called "prepepsinized collagens" (also called "PreCol") which constitute the bulk of the core of the byssus thread. The byssus thread behaves as an elastomer and / or as an elastoplastic polymer depending on whether it is immersed in water or not.

[0004] The characteristics and properties of byssus, in particular the structural, (bio)mechanical, thermal and adhesive properties of byssus have thus enabled its use in numerous applications, in particular in medicine and biotechnology (cf. “Mussel Byssus Fibres: a tough biopolymer”, FG TORRES, OP TRONCOSO at CE TORRES, “chapter” in RSC Green Chemistry, January 2012), in the manufacture of musical instruments (WO2017216203), in the manufacture of shoes (CN107987332, CN113876074), in biocomposite plates (US20130295399), in waste recycling (EP3845691, US11257047), in fabrics such as sea silk (WO22020219930, US20190309173), in fibrous materials (WO202116139), or in coated substrates (WO20214860).

[0005] At the same time, the production of mussels is such that this raw material is not only inexpensive, but extremely accessible in large quantities and is not valued at the level of its production.

[0006] There is therefore a need for the development and application of products from mussel farming. Summary of the invention

[0007] Surprisingly, it has been discovered that byssus fibers can be incorporated into a particular fibrous web, thus presenting interesting properties in terms of insulation (acoustic and / or thermal) and / or fireproofing.

[0008] Thus the object according to the present invention relates to a fibrous web comprising: - as first type of fibers byssus fibers, - at least one second type of fibers, and - at least one binder, characterized in that the quantity of binder is less than or equal to 15% by mass relative to the total mass of the fibrous web.

[0009] Thus, it was possible to obtain a sheet in which the binder is in an amount of less than 15%. By thus limiting the amount of binder, the sheet has characteristics limiting the fire risk of the sheet. Surprisingly, the acoustic insulation properties, as well as the thermal insulation properties, were also significantly improved by limiting the amount of binder.

[0010] Advantageously, the quantity of binder is less than or equal to 12%, less than or equal to 10%, less than or equal to 8%, less than or equal to 6%, less than or equal to 4%, less than or equal to 3%, less than or equal to 2%, by mass relative to the total mass of the fibrous web.

[0011] In other words, the quantity of binder is between 1.5% and 15% by mass relative to the total mass of the fibrous web, for example between 2% and 12%, between 3% and 10%, between 4% and 8%, or between 5% and 6% by mass relative to the total mass of the fibrous web.

[0012] In a particular embodiment, said at least one second type of fibers and said at least one binder is a single-material fiber.

[0013] In a particular embodiment, said at least one second type of fibers and said at least one binder is a multi-material fiber.

[0014] Advantageously, the quantity of byssus fibers is greater than or equal to 70% by mass relative to the total mass of the fibrous sheet.

[0015] Indeed, the more the fibrous web comprises byssus fibers, the more the web will present the interesting characteristics of byssus (acoustic insulation, thermal insulation and / or fireproofing).

[0016] More advantageously, the quantity of byssus fibers is greater than or equal to 75%, greater than or equal to 80%, greater than or equal to 85%, greater than or equal to 90%, greater than or equal to 93%, or even greater than or equal to 95% by mass relative to the total mass of the fibrous web.

[0017] In a particular embodiment, said at least one second type of fibers comprises biopolymer, a synthetic polymer and / or a natural polymer.

[0018] By “natural polymer” it is understood in the context of the present invention that the polymer is extracted from a natural environment (i.e. without human intervention during its synthesis).

[0019] Advantageously, said at least one second type of fibers comprises a synthetic polymer.

[0020] Advantageously, said at least one second type of fiber comprises at least one synthetic polymer such as a PET (polyethylene terephthalate), PP (polypropylene), PLA (lactic acid homopolymer), PE (polyethylene), a copolymer of PLA / coPE, PP / coPE, PET / coPE, PS (polystyrene) / PET, PE / PET, Polyester / PBT, Polyester / coPolyester, PLA / coPLA, PLA / PBS, and / or PET / coPE, as well as mixtures thereof.

[0021] In one embodiment, the synthetic polymers listed above are said to be "modified", for example by an injection of phosphorus onto the molecular chain of the material during the manufacture of the fibers or by the grafting of at least one type of hydrocarbon fragment(s) such as alkyls, esters, ketones, etc. for example C1 to C15 onto these polymers.

[0022] It should be noted that depending on the temperatures at which the manufacturing process is implemented, some of these fibers comprise polymers which can act as a binder (for example PLA, PE, polyester). The choices of nature of said at least one second type of fiber and of the binder are therefore to be adapted according to the desired product and the chosen implementation process.

[0023] Preferably, said at least one second type of fiber comprises a fiber chosen from the list consisting of PET (polyethylene terephthalate), PP (polypropylene), as well as their mixtures.

[0024] Advantageously, said at least one second type of fiber has a melting temperature greater than or equal to 140°C, preferably greater than or equal to 150°C, greater than or equal to 180°C, greater than or equal to 200°C, greater than or equal to 250°C, or even greater than or equal to 300°C.

[0025] Preferably, said at least one second type of fibers comprises PET which has good mechanical strength, resistance to humidity and has a low cost.

[0026] Preferably, said at least one second type of fibers comprises PP which in particular has high mechanical resistance.

[0027] In a particular embodiment, said at least one binder comprises biopolymer, a synthetic polymer and / or a natural polymer.

[0028] Advantageously, said at least one binder comprises a synthetic polymer.

[0029] Advantageously, said at least one binder comprises a binder chosen from the list consisting of PLA (polylactic acid), PE (polyethylene), polyolefin, and any of their mixtures.

[0030] Advantageously, said at least one binder comprises a binder chosen from the list consisting of PLA (polylactic acid), PE (polyethylene), polyolefin, and any of their mixtures.

[0031] Preferably, said at least one binder comprises polyolefin. Polyolefin makes it possible to easily obtain adhesion of the fibers to each other.

[0032] Advantageously, said at least one binder has a melting temperature greater than or equal to 80°C, preferably greater than or equal to 100°C, greater than or equal to 120°C, greater than or equal to 130°C, greater than or equal to 140°C, or even greater than or equal to 150°C.

[0033] Advantageously, said at least one binder has a melting temperature less than or equal to 250°C, preferably less than or equal to 200°C, less than or equal to 180°C, less than or equal to 170°C, less than or equal to 160°C, or even less than or equal to 150°C.

[0034] Advantageously, said at least one binder is a polyolefin and said at least one second type of fiber comprises a PE fiber.

[0035] In a particular embodiment, the quantity of binder is greater than or equal to 1.5% by mass relative to the total mass of the fibrous web.

[0036] Preferably, the quantity of binder is between 1.5 and 15%, for example between 3 and 14%, between 4 and 12%, between 5 and 10%, preferably between 7 and 8%, by mass relative to the total mass of the fibrous sheet.

[0037] By controlling the quantity of binder(s), it is possible to more easily control the density of the resulting web. Indeed, in the various constituents of such a fibrous web, the binders are typically among the heaviest (dense).

[0038] In a particular embodiment, the melting temperature of said at least one binder is lower than that of said at least one second type of fibers.

[0039] Advantageously, the fibrous sheet according to the present invention has a surface density of between 125 g / m2 and 4000 g / m2.

[0040] Preferably, the fibrous sheet according to the present invention has a surface density of between 200 g / m2 and 2000 g / m2, preferably between 250 g / m2 and 1500 g / m2, between 300 g / m2 and 1200 g / m2, between 400 g / m2 and 1100 g / m2, between 500 g / m2 and 1000 g / m2, between 600 g / m2 and 900 g / m2, or between 700 g / m2 and 800 g / m2.

[0041] An object according to the present invention also relates to a ready-to-cook mixture for producing a fibrous sheet as described above, characterized in that said mixture comprises: - byssus fibers, - at least one second type of fiber, and - at least one hot melt binder.

[0042] Furthermore, precise control of the areal density of the fibrous web according to the present invention can be achieved by compacting the ready-to-cook mixture before cooking (e.g., by filling a given volume with a given amount of ready-to-cook mixture which is then cooked to form the fibrous web according to the present invention).

[0043] Thus, advantageously, said at least one second type of fibers and said at least one hot-melt binder are in a combined form of hot-melt fibers.

[0044] One of the advantages of thermo-adhesive fibers is thus to limit the quantity of binder(s) in the fibrous web. Thermo-adhesive fibers in fact have a minimal but sufficient quantity of binder to allow the formation of inter-fiber bonds and allow cohesion of the whole.

[0045] Furthermore, an object according to the present invention relates to a method of manufacturing a ready-to-cook mixture as described above, characterized in that it comprises the following successive steps: a) a step of disentangling byssus fibers, and b) a step of mixing byssus fibers with thermoadhesive fibers.

[0046] The byssus fibers are in fact typically extracted in a manner which may require untangling the different fibers in order to more easily use them later and ensure better homogeneity of the product after addition of the heat-sealing fibers.

[0047] Thermoadhesive fibers are commercially available and are therefore easy to obtain and implement with byssus fibers.

[0048] An object according to the present invention also relates to the use of a fibrous sheet as described above as an insulating material and / or as a fireproofing material.

[0049] Indeed, the particular properties of the fibrous sheet, in particular its lightness, its insulation properties (acoustic and / or thermal) and / or fireproofing, allow various applications of the products (in particular the fibrous sheet) according to the present invention. In particular, a fibrous sheet as described above can be used to lighten insulation products and / or increase their insulation properties (acoustic and / or thermal) and / or fireproofing. Brief description of the drawings

[0050] The invention will be better understood on reading the following description of exemplary embodiments, with reference to the appended drawings in which:

[0051] [Fig.l] [Fig.l] represents a schematic side view of a shredder as used and detailed in the embodiment example below.

[0052] [Fig.2] [Fig.2] represents a schematic side view of an air-brewing mixing cage, as employed and detailed in the embodiment example below.

[0053] [Fig.3] [Fig.3] represents a schematic side view of an oven equipped with conveyor belts, as used and detailed in the embodiment example below.

[0054] [Fig.4] [Fig.4] represents a schematic side view of a calendering device, as used and detailed in the embodiment example below.

[0055] EXAMPLES

[0056] In order to illustrate the present invention, without being specifically limited thereto, an embodiment of the various steps of producing the fibrous web according to the present invention is described below.

[0057] 1. Fraying step

[0058] Fraying is a method of opening fibers, it allows the bundles to be separated and the byssus to be unknotted. For this, a frayer (such as a LAROCHE ® frayer) can be used to open and refine the byssus fibers thanks to its cylinders fitted with needles (as shown for example in [Fig.l]).

[0059] The shredder typically comprises several rollers mounted in series and two terminal rollers mounted one above the other at the end of the chain.

[0060] The “raw” byssus (input material Ei) is typically placed on a conveyor belt IA.

[0061] The conveyor belt IA supplies an input cylinder 2A which compresses the "raw" byssus against a support, such as a horizontal plate or a second input cylinder 2B.

[0062] Following its compression, the material arrives on a set of three rollers 3A, 3B, 3C with spikes moving and fraying the material as it passes. Each roller 3A, 3B, 3C with spikes is provided with an opening allowing the byssus fibers to be sucked up so as to remove the microfibers and the water present in the material.

[0063] The material thus treated then arrives at two terminal rollers 4A, 4B which compact the shredded material between them to produce a shredded and compacted byssus (“output material Si”), typically received on a conveyor belt IB.

[0064] The speed of the rollers 3A, 3B, 3C is chosen between 900 and 1200 revolutions per minute. The percentage of humidity of the byssus fibers varies between 10 and 20% (the legal recovery rate of the byssus fiber being 14.6% humidity). Under these conditions, the yields observed are between 50 and 90% (by mass).

[0065] 2. Mixing step

[0066] A first dosing sub-step makes it possible to determine the quantities of materials and associated percentages of byssus and thermofusible fibers. The thermofusible fibers have a moisture uptake rate of less than 2%. The ratios of the mixtures vary from 50 to 98% byssus and the remainder in thermofusible fibers. These variations make it possible to adapt the material to the use. To make these mixtures of raw material, a simple weighing on a scale is carried out.

[0067] The raw materials used may be byssus and “TREVIRA® bi-component” or another thermofusible fiber. By “bi-component”, it is understood that it is a combination of a fiber and a binder according to the present invention which may be in the form of a thermofusible fiber. The mass percentage of the raw materials: the ratios of the mixtures are variable from 50% byssus to 50% bi-component and up to 98% byssus to 2% bi-component.

[0068] A manual premixing sub-step reduces production time by opening and mixing the two fibers. In practice, this step reduces the number of homogenization passes in the shredder.

[0069] A homogenization sub-step ensures the quality of the final product. It is indeed preferable to obtain a homogeneous mixture between the byssus and the two-component which serves as a binder in the material. The mixture is therefore homogenized by passing it through the shredder (as shown in [Fig.l]), a second pass can be carried out if the homogeneity is not satisfactory. The same settings of the shredder are typically applied here.

[0070] 3. Air-brewing step

[0071] An optional air mixing step makes it possible to homogenize the product (see [Fig. 2]). The bales of material (“input material E2”) are typically placed on a conveyor belt IC then sucked up and sent, for example via a suction pipe 5, into a mixing cage 6 where they are air mixed (mixing represented in [Fig. 2] by a rotating arrow in the upper part of the mixing cage 6). As it passes, the material falls back and passes between cylinders 7 fitted with long spikes before being pressed against a support such as a second perforated conveyor belt 1D.

[0072] The mass of material per bale has a grammage of between 100 and 3000 g.m2. In the industrial laboratory where the tests were carried out, the speed of the second 1D conveyor belt (output) is adjusted so as to be between 0.1 and 1.0 m / min. It should be noted that in industry the speed could go for example up to 1 to 9 m / min depending on the equipment. An output roller 8 is optionally placed above the second 1D conveyor belt (output) at a height (surface to surface) of for example between 2 and 200 mm to obtain a product of a controlled and continuous thickness (“Output material S2”).

[0073] 4. Cooking step

[0074] Cooking can be carried out in several ways. For example, the ready-to-cook material passes through an oven in order to set its shape as shown in [Fig.3]. The input material to be cooked E3 is typically placed on a conveyor belt 1E and heated and then cooled by a succession of hot blocks 10 and cold blocks 11 while being formed between two supports, such as two conveyor belts 1F, 1G each driven by a series of wheels or rollers 9A, 9B. The temperature of the hot blocks 10 can be between 80 and 190°C, depending on the nature of the thermofusible fibers (also called “bi-components”). The temperature of the cold blocks 11 can be between 5 and 70°C, depending on the nature of the thermofusible fibers (also called “bi-components”). In the case where two conveyor belts 1F, 1G are included in the furnace to control the density of the fibrous web (output cooked material S3) according to the present invention, these belts can for example be spaced apart from each other by a distance of between 2 and 200 mm and the belts configured to allow a running speed of between 0.1 and 9.0 meters per minute, for example between 0.1 and 1.0 m / min for an industrial laboratory, and between 1 and 9 m / min for industrial equipment.

[0075] 5. Calendering step ([Fig.4])

[0076] Calendering is an additional step useful for manufacturing a more rigid and thinner product from the products produced according to the steps described above. Calendering thus makes it possible to adjust the final thickness of the product. For example, [Fig.4] represents such a calendering. This method also makes it possible to produce multi-layer complexes from two products. The principle is to pass the material to be calendered E4 between two calendering rollers 13A, 13B to obtain an output calendered material S4. Conveyor belts 1H, 1J can be placed before and after the two calendering rollers 13A, 13B to bring the material E4 to be calendered and then remove the product once calendered (i.e. the output calendered material S4). Any pressure P can be applied between the two calendering rollers 13A, 13B to control the final thickness of the output calendered material S4.For example, the pressure applied by the upper cylinder can be between 2 and 8 bars.

[0077] The calendering rollers 13A, 13B are optionally heated to facilitate the shaping of the fibrous web thus treated.

[0078] 6. Examples of products obtained

[0079] Several products were thus obtained and are summarized in Table 1 below.

[0080] [Table 1]: Examples of products obtained by the process according to the present invention: Composition n° 1 2 3 4 Composition (% mass) 70% byssus 30% TREVIRA ® 255: 1,3dtex; 6m m 70% byssus 30% TREVIRA ® 277: 2.2 dtex; 6mm 80% byssus 20% TREVIRA® 255:l,3dtex;6 mm 90% byssus 10% TREVIRA® 255:l,3dtex;6 mm Cooking temperature and time 190°C for 13 minutes 20s 165°C for 10 minutes 190°C for 10 minutes 179°C for 4min 26s Cooling temperature and time 60°C for 6 minutes 40s 60°C for 5 minutes 50°C for 5 minutes 60°C for 2min 13s Target surface density (g / m2) 2000 2500 2000 500 Surface density measured on a batch (g / m2) 2065 2447 2005 503 Thickness of the sheet obtained (mm) 50 50 50 10

[0081] The product TREVIRA ®255; 1,3dtex, 6mm comprises a core made of polyethylene terephthalate type polymer, covered with copolyolefin (surface layer). The melting point of the core is 256°C and the melting point of the surface layer is 127°C. The cross-section of the fibers is circular.

[0082] 7, Study of the thermal conductivity performances of the products

[0083] Lambda X or thermal conductivity of a material, expressed (in W / mK), represents the capacity of a material to conduct heat. Lambda is an intrinsic characteristic of an insulator.

[0084] Thus, the lower the lambda coefficient, the higher the thermal resistance (R) and therefore the more efficient it will be.

[0085] [Table 2]: Comparison of the products according to the present invention with the insulation products of the state of the art: Insulation products Thermal conductivity at 10°CW / mK) 1 Nature Expanded clay X =0.103 to 0.108 Mineral Vermiculite X =0.090 Mineral Straw X = 0.07 Biological (vegetable) Perlite X = 0.06 Mineral Wood fiber X = 0.038 - 0.069 Biological (vegetable) Cellular glass X =0.055 Mineral Hemp X = 0.039 - 0.045 Organic (plant) Cork X = 0.032 - 0.045 Organic (plant) Rock wool X =0.045 Mineral Glass wool X =0.045 Mineral Resol X =0.0405 Synthetic Expanded polystyrene X =0.0405 Synthetic Extruded polystyrene X =0.040 Synthetic Cellulose wadding X = 0.039 Organic (plant) Linen X = 0.037 Organic (plant) BYSCOPLAK (product no. 3 in table 1) X = 0.035 Organic (including shellfish farming) Polyurethane X = 0.034 Synthetic BYSCOFLEX (product no. 4 in table 1) X = 0.032 Organic (including shellfish farming)

[0086] The products according to the present invention thus exhibit excellent insulating performance in comparison with other products of the state of the art. In addition, the biological (natural) origin of the insulating fibers is an ecological advantage with regard to the manufacture of insulating materials.

[0087] The thermal insulations as a function of the temperature of the BYSCOPLAK and BYSCOFLEX products were measured and reported in the table below: Thermal conductivity result (W / mK) Temperature (°C) -10 0 10 20 30 40 50 BYSOPLAK (product no. 3 in table 1) 0.035 0.034 0.035 0.035 0.037 0.040 0.040 BYSOFLEX (product no. 4 in table 1) 0.03 0.031 0.032 0.035 0.035 0.037 0.039

[0088] These results were obtained with a Lambdameter.

[0089] These results show the interest in terms of insulating performance of the products according to the present invention.

[0090] 8. Study of the flame retardant performance of the products

[0091] Initial comparative results were carried out between the products according to the present invention and products according to the state of the art made of polyethylene terephthalate. These results show the advantages of the products according to the present invention in terms of flame retardancy in comparison with the products according to the state of the art. The panels according to the present invention tested had the composition (% by mass) according to the compositions in Table 1 above and other compositions (compositions provided), but with lower thicknesses (approximately 3 cm for the uncalendered panels and approximately 2 mm for the calendered panels) in order to facilitate their comparison with the panels of the state of the art available (thickness of approximately 3 cm).0%

[0092] A. Non-woven panel; composition No. 1 of Table 1; thickness approximately 3 cm:

[0093] Experiment: 30 seconds above a flame, vertical panel (panel parallel to the flame): - flame with a height between 5 and 7 cm, - presence of smoke, and - crackling.

[0094] The panel has carbonized on two edges of the panel. When removed from the flame: the non-woven panel is extinguishable almost immediately outside the flame.

[0095] B. Non-woven panel; composition no. 1 table 1; thickness approximately 3 cm:

[0096] Experiment: 30 seconds above a flame, horizontal panel (per panel pendulum to the flame): - small flames on the side, - presence of smoke, and - crackling.

[0097] The panel charred on the front side which was subjected to the flame. The fire did not spread through the material so the back side is intact. One of the edges of the panel charred. Upon removal from the flame: the non-woven panel is extinguishable outside the flame after 16 seconds.

[0098] C. Calendered non-woven panel; composition no. 1 table 1; thickness approximately 2 mm:

[0099] Experiment: 30 seconds above a flame, vertical panel (panel parallel to the flame): - flame up to 7 cm, - presence of significant smoke, and - crackling.

[0100] The panel has charred on the edges, one of the faces has partially charred. The fire has not spread through the material so the back face is almost intact. When the flame is removed: the non-woven panel is extinguishable outside the flame after 4 seconds.

[0101] D. Calendered non-woven panel; composition no. 1 table 1; thickness approximately 2 mm:

[0102] Experiment: 30 seconds above a flame, horizontal panel (panel perpendicular to the flame): - small flames on the side, - presence of significant smoke, and - crackling.

[0103] The panel has carbonized on the side exposed to the flame. The fire has not spread through the material and therefore the back side is intact, one edge of the panel has partially carbonized. Upon removal from the flame: the non-woven panel is extinguishable outside the flame after 8 seconds.

[0104] E. Polyethylene terephthalate panel according to the state of the art, thickness approximately 3 cm:

[0105] Experiment: 30 seconds above a flame, vertical panel (panel parallel to the flame): - flame up to 10 cm, - presence of significant black smoke, - crackling, and - falling drops of molten and flaming drops.

[0106] The panel melted. Part of the panel disappeared and significant drops were observed. The fire spread rapidly through the material. When the flame was removed: the panel was extinguishable outside the flame almost immediately. The burning drops, however, were vectors for the spread of the fire.

[0107] F. Polyethylene terephthalate panel according to the state of the art, thickness approximately 3 cm:

[0108] Experiment: 30 seconds above a flame, horizontal panel (panel perpendicular to the flame): - small flames, - presence of significant black smoke, - crackling, and - falling drops of molten and flaming drops.

[0109] The panel melted. Part of the panel disappeared and significant drops were observed. The fire spread rapidly through the material. When the flame was removed: the panel was extinguishable outside the flame almost immediately. The burning drops, however, were vectors for the spread of the fire.

[0110] G. Conclusion of fire exposure

[0111] The panels according to the present invention avoid the formation of incandescent drops observed with an equivalent synthetic product. During the exposure time, the fire did not pass through the panels according to the present invention whereas the polyethylene terephthalate panels quickly melted allowing the fire to pass through the exposed panels. When the flame was removed, all the panels according to the present invention tested went out spontaneously between 0 and 16 seconds.

[0112] The technical advantage of the panels according to the present invention with regard to their fire resistance has therefore been demonstrated.

Claims

Claims

1. Fibrous web comprising: - as first type of fibers byssus fibers, - at least one second type of fibers, and - at least one binder, characterized in that the quantity of binder is less than or equal to 15% by mass relative to the total mass of the fibrous web.

2. Fibrous web according to claim 1, characterized in that the quantity of byssus fibers is greater than or equal to 70% by mass relative to the total mass of the fibrous web.

3. Fibrous web according to claim 1 or 2, characterized in that said at least one second type of fibers comprises at least one synthetic polymer such as PET (polyethylene terephthalate), PP (polypropylene), PLA (lactic acid homopolymer), PE (polyethylene), a copolymer of PLA / coPE, PP / coPE, PET / coPE, PS (polystyrene) / PET, PE / PET, Polyester / PBT, Polyester / co-Polyester, PLA / coPLA, PLA / PBS, and / or PET / coPE, as well as mixtures thereof.

4. Fibrous web according to any one of the preceding claims, characterized in that said at least one binder comprises a binder chosen from the list consisting of PLA, PE, polyolefin, and any of their mixtures.

5. Fibrous web according to any one of the preceding claims, characterized in that said at least one binder is a polyolefin and said at least one second type of fiber comprises a PE fiber.

6. Fibrous web according to any one of the preceding claims, characterized in that the quantity of binder is greater than or equal to 1.5% by mass relative to the total mass of the fibrous web.

7. Fibrous sheet according to any one of the preceding claims, characterized in that it has a surface density of between 125 g / m2 and 4000 g / m2.

8. Ready-to-cook mixture for producing a fibrous sheet according to any one of claims 1 to 7, characterized in that said mixture comprises: - byssus fibers, - at least one second type of fiber, and - at least one hot-melt binder.

9. Ready-to-cook mixture according to claim 8 characterized in that said at least one second type of fibers and said at least one hot-melt binder are in a combined form of hot-melt fibers.

10. A method of manufacturing a ready-to-cook mixture according to claim 8 or 9, characterized in that it comprises the following successive steps: a) a step of disentangling byssus fibers, and b) a step of mixing byssus fibers with heat-sealing fibers.

11. Use of a fibrous web according to any one of claims 1 to 7 as an insulating material and / or as a fireproofing material.

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