Bio-based fibrous web with insulating properties

Abstract

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

Description

Description Title of the invention: BIOSOURCED FIBROUS WEB WITH INSULATING PROPERTIES

[0001] Field of invention

[0002] 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.

[0003] State of the art

[0004] 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 surfaces. Advantages of byssus fibers include their ability to adhere to hard surfaces in aquatic habitats and their high strength and extensibility to withstand wave forces.

[0005] Byssus fibers are composed primarily 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.

[0006] The characteristics and properties of byssus, including structural, (bio)mechanical, thermal and adhesive properties of byssus have thus enabled its use in numerous applications, including medicine and biotechnology (see “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, CN1 13876074), in biocomposite plates (US20130295399), in waste recycling (EP3845691, US11257047), in tissues such as sea ​​silk (W022020219930, US20190309173), in fibrous materials (WO202116139), or in coated substrates (W020214860).

[0007] At the same time, the production of mussels is such that this raw material is not only cheap, but extremely accessible in large quantities and is not valued at the level of its production.

[0008] There is therefore a need for the development and application of products from mussel farming.

[0009] At the same time, it is known to produce objects made from natural fibers as illustrated by international application WO2022 / 229456 which describes an object made from natural fibers comprising marine fibers from the algae Zostera and patent CN1 08005334 which describes a decorative panel comprising a layer formed by a mixture of polyamide, byssus and chitin fibers. Finally IT20210012458 describes a textile obtained by weaving byssus fibers.

[0010] Summary of the invention

[0011] Surprisingly, it was 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.

[0012] Thus the object according to the present invention relates to a fibrous sheet comprising: - as the first type of fibers of byssus fibers, - at least one second type of fiber, 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 sheet.

[0013] This resulted in a web in which the binder is in an amount of less than 15%. By limiting the amount of binder, the web has characteristics that limit the fire risk of the web. Surprisingly, the acoustic insulation properties, as well as the thermal insulation properties, were also significantly improved by limiting the amount of binder.

[0014] 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.

[0015] 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.

[0016] In a particular embodiment, said at least one second type of fibers and said at least one binder is a single-material fiber.

[0017] In a particular embodiment, said at least one second type of fibers and said at least one binder is a multi-material fiber.

[0018] Advantageously, the quantity of byssus fibers is greater than or equal to 70% by mass relative to the total mass of the fibrous web.

[0019] In fact, the more byssus fibers the fibrous web contains, the more the web will present the interesting characteristics of byssus (acoustic insulation, thermal insulation and / or fireproofing).

[0020] 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 greater than or equal to 95% by mass relative to the total mass of the fibrous web.

[0021] In a particular embodiment, said at least one second type of fibers comprises biopolymer, a synthetic polymer and / or a natural polymer.

[0022] 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).

[0023] Advantageously, said at least one second type of fiber comprises a synthetic polymer.

[0024] Advantageously, said at least one second type of fiber 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 / coPolyester, PLA / coPLA, PLA / PBS, and / or PET / coPE, as well as mixtures thereof.

[0025] In one embodiment, the synthetic polymers listed above are said to be "modified", for example by injecting phosphorus into the molecular chain of the material during the manufacture of the fibers or by grafting at least one type of hydrocarbon fragment(s) such as alkyls, esters, ketones, etc., for example C1 to C15, onto these polymers.

[0026] It should be noted that depending on the temperatures at which the manufacturing process is implemented, some of these fibers include polymers that can act as binders (for example PLA, PE, polyester). The choice of nature of said at least one second type of fiber and binder must therefore be adapted according to the desired product and the chosen implementation process.

[0027] 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.

[0028] 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.

[0029] Preferably, said at least one second type of fibers comprises PET which has good mechanical strength, resistance to humidity and has a low cost.

[0030] Preferably, said at least one second type of fibers comprises PP which in particular has high mechanical resistance.

[0031] In a particular embodiment, said at least one binder comprises biopolymer, a synthetic polymer and / or a natural polymer.

[0032] Advantageously, said at least one binder comprises a synthetic polymer.

[0033] 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.

[0034] 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.

[0035] Preferably, said at least one binder comprises polyolefin. The polyolefin makes it possible to easily obtain adhesion of the fibers to each other.

[0036] 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.

[0037] 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.

[0038] Advantageously, said at least one binder is a polyolefin and said at least one second type of fiber comprises a PE fiber.

[0039] 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.

[0040] 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.

[0041] By controlling the amount of binder(s), it is possible to more easily control the density of the resulting web. Indeed, in the different constituents of such a fibrous web, the binders are typically among the heaviest (densest).

[0042] 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.

[0043] Advantageously, the fibrous sheet according to the present invention has a surface density of between 125 g / m 2 and 4000 g / m 2 .

[0044] Preferably, the fibrous sheet according to the present invention has a surface density of between 200 g / m 2 and 2000 g / m 2 , preferably between 250 g / m 2 and 1500 g / m 2 , between 300 g / m 2 and 1200 g / m 2 , between 400 g / m 2 and 1100 g / m 2 , between 500 g / m2 and 1000 g / m 2 , between 600 g / m 2 and 900 g / m 2 , or between 700 g / m 2 and 800 g / m 2 .

[0045] 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.

[0046] 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).

[0047] 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.

[0048] One of the advantages of thermo-adhesive fibers is that they limit the amount of binder(s) in the fiber web. Thermo-adhesive fibers have a minimal but sufficient amount of binder to allow the formation of inter-fiber bonds and ensure overall cohesion.

[0049] Furthermore, an object according to the present invention relates to a method for 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 heat-sealing fibers.

[0050] Byssus fibers are in fact typically extracted in a way that 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.

[0051] Thermobonding fibers are commercially available and are therefore easy to obtain and implement with byssus fibers.

[0052] An object according to the present invention also relates to the use of a fibrous web as described above as an insulating material and / or as a fireproofing material.

[0053] 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.

[0054] Brief description of the drawings

[0055] The invention will be clearly understood upon reading the following description of exemplary embodiments, with reference to the appended drawings in which:

[0056] [Fig. 1] Figure 1 represents a schematic side view of a shredder as used and detailed in the embodiment example below.

[0057] [Fig. 2] Figure 2 represents a schematic side view of an air-brewing mixing cage, as employed and detailed in the embodiment below.

[0058] [Fig. 3] Figure 3 represents a schematic side view of an oven equipped with conveyor belts, as used and detailed in the example embodiment below.

[0059] [Fig. 4] Figure 4 represents a schematic side view of a calendering device, as used and detailed in the embodiment example below.

[0060] EXAMPLES

[0061] 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.

[0062] 1. Fraying step

[0063] Fraying is a method of opening fibers, it allows to separate the bundles and unravel the byssus. For this, a fraying machine (such as a LAROCHE ® fraying machine) can be used to open and refine the byssus fibers thanks to its cylinders lined with needles (as shown for example in figure 1).

[0064] The shredder typically consists of several rollers mounted in series and two terminal rollers mounted one above the other at the end of the line.

[0065] The “raw” byssus (input material Ei) is typically placed on a 1A conveyor belt.

[0066] Conveyor belt 1A feeds an inlet cylinder 2A which compresses the "raw" byssus against a support, such as a horizontal plate or a second inlet cylinder 2B.

[0067] 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 in order to remove the microfibers and the water present in the material.

[0068] 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 (“exit material Si”), typically received on a conveyor belt 1 B.

[0069] The speed of 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 observed yields are between 50 and 90% (by mass).

[0070] 2. Mixing step

[0071] A first dosing sub-step determines the quantities of materials and associated percentages of byssus and thermofusible fibers. Thermofusible fibers have a moisture absorption rate of less than 2%. The ratios of the mixtures vary from 50 to 98% byssus and the remainder in thermofusible fibers. These variations allow the material to be adapted to the use. To make these raw material mixtures, a simple weighing on a scale is carried out.

[0072] 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.

[0073] A manual premixing sub-step reduces production time by opening and mixing the two fibers. In practical terms, this step reduces the number of homogenization passes in the shredder.

[0074] 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 Figure 1); a second pass can be carried out if the homogeneity is not satisfactory. The same shredder settings are typically applied here.

[0075] 3. Air-brewing step

[0076] An optional air mixing step allows the product to be homogenized (see Figure 2). The bales of material ("input material E2") are typically placed on a conveyor belt 1C 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 Figure 2 by a rotating arrow in the upper part of the mixing cage 6). As it goes along, the material falls back down and passes between cylinders 7 fitted with long spikes before being pressed against a support such as a second perforated conveyor belt 1 D.

[0077] The mass of material per bale has a grammage of between 100 and 3000 gm 2. In the industrial laboratory where the tests were carried out, the speed of the second conveyor belt 1 D (output) is set 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 conveyor belt 1 D (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”).

[0078] 4. Cooking step

[0079] 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 Figure 3. The input material to be cooked E3 is typically placed on a conveyor belt 1 E and heated then cooled by a succession of hot blocks 10 and cold blocks 11 while being formed between two supports, such as two conveyor belts 1 F, 1 G each actuated 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 1 F, 1 G 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.

[0080] 5. Calendering step (figure 4)

[0081] Calendering is an additional step that is useful for manufacturing thinner and more rigid products from products made using the steps described above. Calendering thus allows the final thickness of the product to be adjusted. For example, Figure 4 shows such a calendering process. This process 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 a calendered output material S4. Conveyor belts 1 H, 1 J 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.

[0082] The calendering rollers 13A, 13B are optionally heated to facilitate the shaping of the fibrous web thus treated.

[0083] 6. Examples of products obtained

[0084] Several products were thus obtained and are summarized in Table 1 below.

[0085] [Table 1]: Examples of products obtained by the process according to the present invention:

[0086] The TREVIRA ®255;1,3dtex, 6mm product consists of a core made of polyethylene terephthalate 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 fiber cross-section is circular.

[0087] 7. Study of thermal conductivity performance of products

[0088] The lambda 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.

[0089] Thus, the lower the lambda coefficient, the higher the thermal resistance (R) and therefore the more efficient it will be.

[0090] [Table 2]: Comparison of the products according to the present invention with the insulation products of the state of the art:

[0091] The products according to the present invention thus exhibit excellent insulating performance compared to other products of the prior art. In addition, the biological (natural) origin of the insulating fibers is an ecological advantage in the manufacture of insulating materials.

[0092] Thermal insulation depending on the temperature of the products BYSCOPLAK and BYSCOFLEX were measured and reported in the table below:

[0093] These results were obtained with a Lambdameter.

[0094] These results show the interest in terms of insulating performance of the products according to the present invention.

[0095] 8. Study of the flame retardant performance of the products

[0096] Initial comparative results were conducted between the products according to the present invention and products according to the state of the art in polyethylene terephthalate. These results make it possible to note the advantages of the products according to the present invention in terms of fireproofing 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 state-of-the-art panels available (thickness of approximately 3 cm).0%

[0097] A. Non-woven panel; composition No. 1 of Table 1; thickness approximately 3 cm:

[0098] 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.

[0099] The panel has charred on two edges of the panel. When removed from the flame: the non-woven panel is extinguishable almost immediately outside the flame.

[0100] B. Non-woven panel; composition no. 1 table 1; thickness approximately 3 cm:

[0101] Experiment: 30 seconds above a flame, horizontal panel (panel perpendicular to the flame): - small flames on the side, - presence of smoke, and - crackling.

[0102] The panel charred on the front side, which was exposed to the flame. The fire did not spread through the material, so the back side is intact. One of the panel's edges charred. Upon removal from the flame: the non-woven panel is extinguishable outside the flame after 16 seconds.

[0103] C. Calendered non-woven panel; composition no. 1 table 1; thickness approximately 2 mm:

[0104] Experiment: 30 seconds above a flame, vertical panel (panel parallel to the flame): - flame up to 7 cm, - presence of significant smoke, and - crackling.

[0105] The panel was charred on the edges, one of the faces was partially charred. The fire did not spread through the material, so the back face is almost intact. When removed from the flame: the non-woven panel is extinguishable outside the flame after 4 seconds.

[0106] D. Calendered non-woven panel; composition no. 1 table 1; thickness approximately 2 mm:

[0107] Experiment: 30 seconds above a flame, horizontal panel (panel perpendicular to the flame): - small flames on the side, - presence of significant smoke, and - crackling.

[0108] The panel charred on the side exposed to the flame. The fire did not spread through the material and therefore the back side is intact, one edge of the panel partially charred. Upon removal from the flame: the nonwoven panel is extinguishable outside the flame after 8 seconds.

[0109] E. Polyethylene terephthalate panel according to the state of the art, thickness approximately 3 cm:

[0110] 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.

[0111] The panel melted. Part of the panel disappeared, and significant drops of fire were observed. The fire spread rapidly through the material. When the flame was removed, the panel was almost immediately extinguishable outside the flame. However, the burning drops were vectors for the spread of the fire.

[0112] F. State-of-the-art polyethylene terephthalate panel, thickness approximately 3 cm:

[0113] 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.

[0114] The panel melted. Part of the panel disappeared, and significant drops of fire were observed. The fire spread rapidly through the material. When the flame was removed, the panel was almost immediately extinguishable outside the flame. However, the burning drops were vectors for the spread of the fire.

[0115] G. Conclusion of fire exposure

[0116] 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. Upon removal of the flame, all the panels according to the present invention tested extinguished spontaneously between 0 and 16 seconds.

[0117] 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 the first type of fibers of byssus fibers, - at least one second type of fiber, 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 sheet.

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 / coPolyester, 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 sheet 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 sheet.

7. Fibrous sheet according to any one of the preceding claims, characterized in that it has a surface density of between 125 g / m 2 and 4000 g / m 2 .

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.

Images