Silk protein-based composite, vehicle seat and associated manufacturing method

Abstract

Silk protein-based composite, vehicle seat, and associated manufacturing method. The present invention relates to a composite complex (10) comprising at least one substrate layer (20) and at least one coating layer (30) applied to the substrate layer (20), the substrate layer (20) being a fabric. The coating layer (30) is a gel formed from silk proteins, the silk proteins being obtained by fermentation of at least one microorganism in a liquid medium. Figure for the abstract: Figure 1

Description

Title of the invention: Silk protein-based composite, vehicle seat and associated manufacturing method

[0001] The present invention relates to a composite complex, of the type comprising at least one substrate layer and at least one coating layer applied to the substrate layer, the substrate layer being a fabric.

[0002] The invention also relates to a vehicle seat comprising a body covered by at least one headrest formed by such a composite complex.

[0003] Finally, the invention also relates to a method for manufacturing such a composite complex.

[0004] It is known to use in the automotive field complexes of animal origin, such as animal leather, to cover certain parts of the seats or the passenger compartment of a vehicle.

[0005] For ethical reasons and out of respect for the environment, leather is often replaced today by imitation leather or, generally, by a fabric made of fibers and covered with a coating layer.

[0006] Such complexes, called composite complexes, are valued for their mechanical properties, the fibers generally providing some mechanical resistance to the complex, their aesthetic properties, as well as for their lightness.

[0007] The coating layer protects the fabric, provides the texture and final aesthetics to the composite complex and, for practical reasons, is often made of plastic.

[0008] On the other hand, it may prove difficult to recycle such a composite complex, in particular because the separation of the fabric and the plastic coating layer can be complicated.

[0009] One of the goals of the invention is therefore to propose an eco-responsible composite complex, which respects the environment and ethical standards, and which is easily recyclable.

[0010] To this end, the invention relates to a composite complex of the aforementioned type, in which the coating layer is a gel formed of silk proteins, the silk proteins being obtained by fermentation of at least one microorganism in a liquid medium.

[0011] Since the silk proteins are obtained by fermentation of a microorganism, the composite complex is environmentally friendly, the coating layer being biodegradable. Furthermore, the same microorganism can be used to form the fibers of the substrate layer, which makes the composite complex particularly simple and economical to produce.

[0012] Moreover, by its biodegradable nature, the coating layer allows the composite complex to be easily recycled.

[0013] According to other advantageous aspects of the invention, the composite complex comprises one or more of the following features, taken individually or in all technically possible combinations:

[0014] - the substrate layer comprises silk fibers;

[0015] - silk fibers are obtained by spinning a fermentation product of the minus one microorganism in said liquid medium;

[0016] - at least one microorganism is a yeast and / or a bacterium;

[0017] - the composite complex exhibits an elongation at break greater than 30%, preferably between 30% and 150%;

[0018] - the substrate layer is applied on a lower layer, the layer lower being formed of silk proteins, the silk proteins being obtained by fermentation of at least one microorganism in said liquid medium;

[0019] - the lower layer comprises a plurality of alveoli containing a gas, the layer lower having a foamy structure;

[0020] - the composite complex is made of a single material, each layer being formed from silk proteins.

[0021] The invention also relates to a vehicle seat comprising a body covered by at least one cover, said cover being formed by a composite complex as described above, the covering layer forming at least a part of the external surface of said cover.

[0022] The invention also relates to a method for manufacturing such a composite complex, the method comprising the following steps: fermentation of at least one microorganism in a liquid medium to obtain silk proteins; filtration, purification and reformulation of the silk proteins obtained using additives such as a plasticizer or a hardening agent to obtain the coating layer or each coating layer; application of the coating layer or each coating layer in liquid or viscous state onto at least one substrate layer; and heating of the composite complex until the coating layer or each coating layer solidifies.

[0023] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0024] [Fig-1] [Fig.1] is a schematic cross-sectional representation of a composite based of silk proteins according to the invention in a first embodiment,

[0025] [Fig.2] [Fig.2] is a schematic cross-sectional representation of a composite based of silk proteins according to the invention in a second embodiment, and

[0026] [Fig.3] [Fig.3] is a schematic cross-sectional representation of a silk protein-based composite according to the invention in a third embodiment.

[0027] With reference to [Fig.1], a composite complex 10 is shown.

[0028] A complex is understood to be a heterogeneous mixture of at least two materials different and / or similar but present in a different state or an assembly of at least two layers of different and / or similar materials but present in a different state.

[0029] The composite complex 10 according to the invention can be used in the textile industry, such as in leather goods for example, or in the automotive field, for example to cover a part of a vehicle seat, or a part of the passenger compartment of a vehicle, such as a dashboard, a door panel, etc.

[0030] In a particular embodiment, the composite assembly 10 is used in a transport vehicle. For example, the vehicle comprises one or more seats including a body covered by at least one headrest formed by the composite assembly 10.

[0031] The composite complex 10 extends between an internal surface 12 and an external surface 14 and comprises at least one substrate layer 20 and at least one coating layer 30 applied to the substrate layer 20.

[0032] When the composite complex 10 is intended to cover a vehicle seat, the internal surface 12 is intended to be applied to the side of the vehicle seat frame, for example on a seat cushion, while the external surface 14 forms the visible surface of the seat from inside the vehicle's passenger compartment.

[0033] For example, the substrate layer 20 forms at least part of the internal surface 12 and the coating layer 30 forms at least part of the external surface 14 of the composite complex 10.

[0034] The substrate layer 20 is a fabric, for example formed of long or short fibers, woven or non-woven.

[0035] In the example of the composite assembly 10 used as a vehicle seat cover, the coating layer 30 forms at least a part of the external surface of said cover. In other words, the substrate layer 20 forms an internal part of the cover, being, for example, assembled on the side of the seat frame, and the coating layer 30 forms the external surface, visible from inside the vehicle to a vehicle occupant.

[0036] In the embodiment shown in [Fig. 1], the composite complex 10 comprises a plurality of substrate layers 20 alternately assembled with a coating layer 30. For example, the substrate layers 20 and the layers of The coating layers 30 are alternately laminated, heated and pressurized to form the composite complex 10. The fusion and impregnation of the coating layer 30 into the substrate layer 20 results in a strong assembly in which the layers are firmly fixed to each other.

[0037] The or each layer of substrate 20 and the or each layer of coating 30 has a thickness, for example, between 0.1 mm and 0.3 mm.

[0038] More generally, the thickness of the composite complex, taken between the internal surface 12 and the external surface 14, is for example between 0.5 mm and 1 mm.

[0039] In a preferred embodiment, shown in [Fig.2], the composite complex 10 comprises a single substrate layer 20 on which a coating layer 30 is assembled, the coating layer 30 forming the external surface 14 of the composite complex 10.

[0040] The substrate layer 20 is, for example, a fabric comprising silk fibers.

[0041] Silk fibers are generally obtained from a protein called silk fibroin.

[0042] Silk fibroin may contain a silk polypeptide selected from the group consisting of a natural silk protein and an artificial silk protein derived from a natural silk protein.

[0043] In a first example, silk fibroin is produced by an animal such as a silkworm or a spider. Silk fibers are obtained, for example, from silkworms, which produce them to weave their cocoons for protection during the pupal stage.

[0044] The large sphincter signet protein is an example of a natural silk protein produced in a gland of a specific spider. Such a protein can be used to form the fibers of the substrate layer 20. This protein notably possesses a crystalline region and an amorphous (non-crystalline) region, giving it high strength as well as high deformability.

[0045] On the other hand, in a preferred embodiment, fibroin is artificially manufactured using microorganisms.

[0046] Indeed, most of the living beings (silkworms, spiders, etc.) used in the silk industry do not live beyond the pupal stage because they are boiled or gassed alive in their cocoons in order to allow workers to harvest the silk threads.

[0047] In order to obtain a more eco-friendly and environmentally sound composite complex, particularly one that is safe for animals, it is preferable to use microorganisms, also called host organisms, capable of producing the silk proteins that will be used to manufacture silk fibers. In particular, a protein can be produced by expressing a nucleic acid by a transformed host organism. with an expression vector. The expression vector is a sequence of deoxyribonucleic acid (DNA) that carries the gene coding for the protein that one seeks to synthesize. In other words, the expression vector is designed to transfer a specific gene (the gene coding for the protein of interest) and have it expressed in a host organism that is not its cell of origin (a silkworm or silk spider cell, for example).

[0048] It is thus possible to synthesize a polypeptide derived from a natural silk protein, for example, a polypeptide derived from the greater sphincter signet protein. Examples of proteins derived from a greater sphincter signet include a protein consisting of a sequence represented by the formula: [(A)n motif-REP]m, in which, “(A)n motif” represents an amino acid sequence and is mainly composed of an alanine residue, n being an integer between 2 and 20, “REP” represents an amino acid sequence consisting of 2 to 200 amino acid residues, and m represents an integer between 2 and 300. Such a protein is simple to synthesize and exhibits properties comparable to the natural greater sphincter signet protein in terms of strength and toughness.

[0049] This synthesis is carried out for example by fermentation of a microorganism (host organism) transformed by an expression vector, which under particular constraints, is able to produce the protein encoded by the chosen expression vector.

[0050] The microorganism is for example a eukaryotic or prokaryotic cell, and is for example chosen from a yeast (belonging for example to the genus Saccharomyces, Pichia, or Schizosaccharomyces), a filamentous fungus (belonging for example to the genus Aspergillus, Penicillium, or Trichoderma), an insect cell, an animal cell or a plant cell.

[0051] A prokaryotic host is for example chosen from bacteria belonging to the genus Escherichia, such as Escherichia coli bacteria and others.

[0052] What is meant by "fermentation" of the host microorganism will now be described in more detail.

[0053] As explained previously, fermentation makes it possible to manufacture a protein by cultivating a host transformed by an expression vector in a culture medium, producing, accumulating and harvesting said protein in the culture medium.

[0054] The culture medium is a liquid medium, for example a natural medium or a synthetic medium.

[0055] A microorganism as described above is cultured in said culture medium and fed so that, during its digestion, it produces the protein for which the gene carried by the expression vector codes.

[0056] During fermentation, certain nutritional inputs are necessary for microorganisms to grow properly, such as an input of water, a source of carbon (glucose, fructose, sucrose, carbohydrates for example), and / or nitrogen (ammonia, ammonium chloride, ammonium sulfate, ammonium acetate and ammonium phosphate, for example), or an input of inorganic salts (potassium or magnesium phosphate, magnesium sulfate, sodium chloride, calcium carbonate, for example).

[0057] The culture temperature is, for example, between 10°C and 30°C, and the culture duration is generally between 15 hours and one week. The pH of the culture medium during the culture is preferably maintained between 3.0 and 9.0.

[0058] Once the silk fibroin has been synthesized and harvested, it is isolated and purified according to known methods of isolation, extraction and purification (solvent extraction, chromatography, precipitation, filtration, etc.).

[0059] The silk fibroins thus obtained are then added to a solvent, such as dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), hexafluoroisopronol (HFIP), or similar, to which additives such as a plasticizer or a hardening agent are added in order to obtain a suspension, in particular a gel formed from silk fibroins. This gel formed from silk proteins / fibroins is thus considered to be one of the fermentation products of said microorganisms.

[0060] As mentioned previously, in one particular embodiment, the gel formed from silk proteins is then spun to obtain silk fibers, and to produce the fabric of the substrate layer 20.

[0061] The substrate layer 20 can be made from the gel formed from silk proteins obtained by fermentation of said microorganism, or from a gel formed from natural silk proteins.

[0062] It is possible to obtain a silk protein fibre by spinning according to a known spinning method such as wet spinning or dry spinning.

[0063] Generally, an extrusion device is used to spin and wind the gel formed from silk proteins in order to obtain said silk fibers.

[0064] The fibers obtained are preferably long fibers. Alternatively, the fibers obtained are short fibers.

[0065] The silk fibres obtained can be used alone or in combination with other animal or vegetable textile fibres, and can be woven (for example in a plain weave, twill, satin, etc.) or not.

[0066] In a preferred embodiment, the substrate layer 20 contains exclusively silk fibers.

[0067] According to the invention, the coating layer 30 is a gel formed from silk proteins.

[0068] Silk proteins are obtained by fermentation of at least one microorganism in a liquid medium.

[0069] For example, silk proteins are obtained by the fermentation process of a microorganism as described above, and the gel formed from silk proteins (fermentation product) is used to form the coating layer.

[0070] According to one embodiment, the fermentation of the microorganism makes it possible to obtain a gel in the form of silk proteins, from which both the silk protein fibers for the substrate layer 20 and the coating layer 30 are formed.

[0071] According to another embodiment, the coating layer 30 is applied to a substrate layer 20 comprising any other type of fibers than silk protein fibers, for example animal, vegetable, or synthetic fibers.

[0072] In the embodiment where the composite complex 10 comprises a single substrate layer 20 on which a coating layer 30 is assembled, the gel formed from silk proteins is first applied in liquid or viscous state to the substrate layer 20.

[0073] The application is done for example roughly at first, then the excess gel is removed with a blade in a second step, so as to obtain the desired gel thickness.

[0074] The gel applied to the substrate layer 20 is then heated and / or pressurized until solidification. For example, the gel is heated several times at a temperature between 90 °C and 150 °C, for a duration of between 1 minute and 60 minutes, until the coating layer 30 is solid.

[0075] The heating step allows the water present in the gel to evaporate, and thus hardens the gel in order to obtain the desired coating layer 30.

[0076] Once the coating layer 30 is dry, the composite complex 10 has an elongation at break greater than 30%, for example between 30% and 150%.

[0077] Elongation at break is a dimensionless quantity obtained using a tensile test, allowing the characterization of the deformation behavior of a complex, in particular defining the ability of a complex to elongate before breaking when subjected to tension.

[0078] In the embodiment where the composite complex 10 comprises a plurality of substrate layers 20 onto which a coating layer 30 is applied, the silk protein gel is first applied in a liquid or viscous state onto a first substrate layer 20. Before heating the gel applied to the first substrate layer 20, a second substrate layer 20 is applied to the still viscous and / or liquid coating layer 30. The resulting layers are then heated and / or pressurized until the coating layer solidifies. 30. Then a new coating layer 30 can then be applied as before on the last substrate layer 20 and so on.

[0079] Thus, in each of the embodiments, there is no need to add an adhesive material between the substrate layer or each layer 20 and the coating layer or each layer 30, the gel in the liquid and / or viscous state forming the coating layer 30 before heating serves as a binder between the substrate layer or each layer 20 and the coating layer or each layer 30.

[0080] The coating layer 30 forms, for example, at least part of the external surface of the composite assembly 10. It protects the substrate layer 20 from external aggressions. The coating layer 30 thus gives the composite assembly 10 its aesthetic appearance. It can be transparent or translucent, so that the substrate layer 20 is visible through the coating layer 30.

[0081] Alternatively, the coating layer 30 is opaque, coloured or colourless, textured, smooth, or otherwise.

[0082] In a particular embodiment, shown in [Fig.3], the substrate layer 20 is applied to a lower layer 40. The lower layer 40 forms, for example, at least part of the internal surface of the composite complex 10. It is, for example, intended to be applied to the padding or the frame of a vehicle seat.

[0083] The lower layer 40 is, for example, formed from silk proteins obtained by the fermentation process of a microorganism in a liquid medium as described above. It is, for example, formed similarly to the coating layer 30, in particular from the fermentation product as described above (gel formed from silk proteins).

[0084] In one embodiment, the lower layer 40 comprises a plurality of alveoli containing a gas. For example, a gas is injected into the lower layer 40, in particular into the gel composed of silk proteins forming the lower layer 40, in order to create an alveolar structure.

[0085] The lower layer 40 then has a foam structure and provides a feeling of comfort to a vehicle occupant, particularly when the composite assembly 10 is intended to form part of a vehicle seat cover. Thus, according to one embodiment, the lower layer 40 can form all or part of the padding of a vehicle seat.

[0086] For example, the lower layer 40 is able to deform so as to conform to the shape of the vehicle part on which it is applied and so as to sink elastically when pressure is exerted on one of its faces, in particular from the internal surface of the composite complex 10.

[0087] In this embodiment, the silk protein gel is first applied in liquid or viscous state to a first side of the substrate layer 20, then heated and / or pressurized as before to form the coating layer 30. The silk protein gel is then applied to a second side of the substrate layer 20 to form the lower layer 40.

[0088] In the example where the lower layer 40 comprises a plurality of alveoli containing a gas, gas is injected into the gel forming the lower layer 40.

[0089] The lower layer 40 is then heated and / or pressurized in turn until solidification.

[0090] In a preferred embodiment, the composite complex 10 is made of a single material. In other words, each layer composing it is formed of the same material, and more particularly is formed from silk proteins.

[0091] Furthermore, as described previously, the assembly of the different layers of the composite complex 10 together does not require the addition of a different material, such as glue or other.

[0092] Such a composite complex 10 is then easily recycled. Indeed, on the one hand, there is not necessarily a need to separate the layers in order to recycle them individually, and on the other hand, the recycling product of a layer can be used, after appropriate transformation, to produce another layer of the composite complex 10, or another composite complex 10.

[0093] The composite complex 10 according to the invention has many advantages.

[0094] Such a composite complex is particularly advantageous because silk fibers are very light, delicate, but also very strong and exhibit remarkable isothermal properties.

[0095] The composite complex 10 has a satisfactory and comfortable appearance which integrates particularly well into the passenger compartment of a vehicle.

[0096] The composite complex 10 is also eco-friendly, in particular because it contains a biological, biodegradable, vegan and environmentally friendly coating layer.

[0097] Finally, the substrate layer 20 provides a certain mechanical strength to the composite complex 10, and the substrate is effectively protected from external aggressions thanks to the presence of the coating layer.

Claims

Demands

1. Composite complex (10) comprising at least one substrate layer (20) and at least one coating layer (30) applied to the substrate layer (20), the substrate layer (20) being a fabric, characterized in that the coating layer (30) is a gel formed of silk proteins, the silk proteins being obtained by fermentation of at least one microorganism in a liquid medium.

2. Composite complex (10) according to claim 1, wherein the substrate layer (20) comprises silk fibers.

3. Composite complex (10) according to claim 2, wherein the silk fibers are obtained by spinning a fermentation product of at least one microorganism in said liquid medium.

4. Composite complex (10) according to any one of the preceding claims, wherein at least one microorganism is a yeast and / or a bacterium.

5. Composite complex (10) according to any one of the preceding claims, having an elongation at break greater than 30%, preferably between 30% and 150%.

6. Composite complex (10) according to any one of the preceding claims, wherein the substrate layer (20) is applied to a lower layer (40), the lower layer (40) being formed of silk proteins, the silk proteins being obtained by fermentation of at least one microorganism in said liquid medium.

7. Composite complex (10) according to claim 6, wherein the lower layer (40) comprises a plurality of gas-containing cells, the lower layer (40) having a foamy structure.

8. Composite complex (10) according to any one of the preceding claims, wherein the composite complex (10) is mono-material, each layer being formed from silk proteins.

9. Vehicle seat comprising a body covered by at least one cap, said cap being formed by a composite complex (10) according to any one of claims 1 to 8, the coating layer (30) forming at least a part of the external surface of said cap.

10. A method for manufacturing a composite complex (10) according to any one of claims 1 to 8, comprising the following steps: - fermentation of at least one microorganism in a liquid medium to obtain silk proteins, - filtration, purification and reformulation of the silk proteins obtained using additives such as a plasticizer or a hardening agent to obtain the coating layer or each layer (30), - application of the coating layer or each layer (30) in liquid or viscous state onto the at least one substrate layer (20), and - heating of the composite complex (10) until the coating layer or each layer (30) solidifies.

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