Multilayer material comprising at least one creep zone

Abstract

The present invention relates to a multilayer material (1a, 1b, 1c) comprising at least: - a first layer (2), - a second layer (3), and - a third layer (4), characterized in that it comprises a first creep zone (5) of at least a portion of the first layer (2) through at least a portion of the second layer (3). Figure for the abstract: Fig 1D

Description

Title of the invention: Multilayer material comprising at least one creep zone Technical field

[0001] The present invention relates generally to multilayer materials, and more specifically to multilayer materials intended to be integrated within a fuel tank, in particular an aircraft tank, such as a helicopter or a drone.

[0002] In particular, the invention relates to a specific multilayer material, a method of manufacturing such a multilayer material, a fuel tank comprising such a multilayer material and an aircraft comprising such a fuel tank. State of the art

[0003] State-of-the-art fuel tanks can be classified into two main families, including integral tanks and flexible tanks.

[0004] More particularly, flexible tanks are tanks that need to be held by a structure. Integral tanks are rigid tanks that do not require a holding structure.

[0005] Thus, among the integral tanks and the flexible tanks, only the flexible tanks have an “anti-crash” function. Indeed, the walls of the flexible tanks alone ensure the sealing and crash resistance functions.

[0006] However, flexible tanks need to be held by a structure which can be:

[0007] - a primary structure of the aircraft, or

[0008] - an additional structure, also referred to as “ad tank” "ditional".

[0009] An additional tank may be, for example, a box, in particular a rigid box.

[0010] Furthermore, for current tanks, when a box is present, the constituent elements of the flexible walls and the boxes are manufactured and cooked separately before being assembled.

[0011] The flexible walls may be attached to a box by fastening means, such as ropes, textile hook and loop fastening systems, and metal rings.

[0012] The boxes have a “structural” function by ensuring that the tank is held in place by the aircraft. They also allow the transport and handling of the assembly consisting of the flexible wall arranged in the box.

[0013] Standard flexible anti-crash tanks can be integrated into helicopters, generally in areas of the structure, provided from the design of the helicopter, and fixed to such a structure.

[0014] The boxes are then additional tanks which are added as needed.

[0015] Thus, in the context of flexible tanks, the use of attachment means represents a significant mass.

[0016] Various solutions have been proposed to address the general problem of weight reduction which contributes to the decarbonization of aviation, at a time when climate change is a major concern for many legislative and regulatory bodies across the world.

[0017] Indeed, various restrictions on carbon emissions have been, are being or will be adopted by various states. In particular, ambitious objectives apply both to new types of aircraft but also to those in circulation requiring the implementation of technological solutions in order to make them compliant with current regulations. Civil aviation has been mobilizing for several years now to make a contribution to the fight against climate change.

[0018] Technological research efforts have already made it possible to significantly improve the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive aeronautical components and products.

[0019] The development of composite materials has been explored in particular to address such a problem of mass reduction. Optimized composite materials have been obtained and thus have a minimum mass to withstand the expected load factors.

[0020] However, there is a need for ever lighter materials and thus to contribute to reducing the environmental impact of aircraft. Statement of the invention

[0021] The invention therefore aims to provide a lightweight multilayer material making it possible to obtain lightweight fuel tanks while also retaining all the mechanical properties required for a fuel tank, in particular for an aircraft.

[0022] The subject of the invention is therefore a multilayer material comprising at least:

[0023] - a first layer,

[0024] - a second layer, and

[0025] - a third layer,

[0026] wherein the multi-layer material comprises a first zone of terminating at least a portion of the first layer through at least a portion of the second layer.

[0027] In particular, the first layer may comprise at least one first rubber, in particular comprising at least one diene elastomer and / or at least one thermoplastic compound.

[0028] In addition, the second layer may comprise at least one fabric, in particular comprising at least one fiber, in particular having an elongation rate greater than or equal to 15%.

[0029] Furthermore, the third layer may comprise at least one composite material, in particular comprising a reinforcing textile and a matrix. In such an arrangement, the matrix may comprise at least one thermosetting resin and the reinforcing textile may comprise at least one fiber having an elongation rate of less than or equal to 5%.

[0030] Finally, optionally, the multilayer material may comprise at least a fourth layer arranged between the second layer and the third layer.

[0031] In particular, the fourth layer may comprise at least one second rubber, in particular comprising at least one diene elastomer and / or at least one thermoplastic compound.

[0032] In the absence of the fourth layer, the multilayer material may include a second zone of creep from at least a portion of the second layer through at least a portion of the third layer.

[0033] In the presence of the fourth layer, the multilayer material may comprise at least a third zone of creep from at least a portion of the fourth layer through at least a portion of the second layer.

[0034] Optionally, the multilayer material may comprise at least a fifth layer disposed between the third layer and the second layer or the fourth layer.

[0035] In particular, the multilayer material may comprise at least a fourth creep zone of at least a portion of the third layer through at least a portion of the fifth layer.

[0036] Advantageously, the diene elastomer may be chosen from polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers and their mixtures, in particular polybutadienes, butadiene copolymers and their mixtures, in particular from butadiene copolymers, in particular from butadiene and acrylonitrile copolymers.

[0037] Advantageously, the thermoplastic compound may be a polymer chosen from:

[0038] - polyamides, such as Polyamide 6 (Pa6), Polyamide 6-6 (Pa6.6), Pal 1, Pal2, Pa6.12, Pa4.6,

[0039] - co-polyamides, aromatic polyamides, polyimides,

[0040] - polyphenylene sulfides, fluorinated polymers, such as poly(phenylene fluoride) vinyl) (PVF), poly(vinylidene fluoride) (PVDF), ethylene tetrafluoroethylene (ETFE) or perfluoroalkoxy (PFA), in particular halogenated thermoplastic resins, polyether ketones such as polyetheretherketone (PEEK) or poly-etherketoneketone (PEKK), or ethylene-polyvinyl alcohol (EVOH), polyurethane, nitrile and its derivatives such as hydrogenated nitrile or nitrile / poly(vinyl chloride) (PVC), epichlorohydrin and its derivatives, fluoropolymer and its derivatives, polychloroprene and fluorosilicone, in particular chosen from halogenated thermoplastic resins, in particular poly(vinyl tetrafluoride), poly(vinyl fluoride), poly(vinylidene chloride) and / or poly(vinyl chloride).

[0041] Advantageously, the diene elastomer is chosen from polybutadienes, butadiene copolymers and their mixtures, in particular from butadiene copolymers, in particular from butadiene and acrylonitrile copolymers, and / or

[0042] the thermoplastic compound is chosen from halogenated thermoplastic resins, in particular poly(vinyl tetrafluoride), poly(vinyl fluoride), poly(vinylidene chloride) and / or poly(vinyl chloride).

[0043] Furthermore, the fiber having an elongation rate greater than or equal to 15% is likely to be an aramid fiber, such as a meta-aramid fiber, poly(m-phenyleneisophthalamide) (MPD-I) Nomex® marketed by the company Du Pont de Nemours Kermel®; a polyamide fiber, such as Pa 6.6 HT, in particular Enka® or Dupont® Nylon, Pa 6 HT, in particular Enkalon®, Pa 4.6 HP, in particular Stanylenka®; a polyether ether ketone (PEEK) fiber, such as those manufactured by Zyex Ltd; Teflon®, polypropylene and / or a polyester fiber, such as PES HT (high tenacity polyester), in particular Trevira®, Dacron®; more specifically an aramid, polyamide and / or polyester fiber.

[0044] According to one embodiment, the thermosetting resin may be an epoxy resin, a polyester resin or a rigid resin, such as PPS, PEEK, PEL, in particular an epoxy resin.

[0045] Advantageously, the fiber having an elongation rate of less than or equal to 5% may be a carbon fiber, in particular high modulus carbon or high strength carbon; a polyethylene fiber, in particular high tenacity polyethylene, high modulus polyethylene, high performance polyethylene, high strength polyethylene, an example of which is Spectra®, ultra high molecular weight polyethylene, an example of which is Dyneema®; an aramid fiber, in particular a para-aramid fiber, such as Kevlar®, Twaron® and Technora®; and / or a glass fiber, in particular an S-glass, R-glass and E-glass fiber; in particular a carbon fiber, an aramid fiber and / or a glass fiber.

[0046] The invention also relates to a method for manufacturing the multilayer material according to the invention, comprising at least:

[0047] i) a step of depositing a first layer, during which a first layer, in particular comprising at least one first rubber, is deposited, in particular on a support;

[0048] ii) a step of depositing a second layer, during which a second layer, in particular comprising at least one fabric, is deposited, in particular on the first rubber;

[0049] iii) a step of depositing a third layer, during which a third layer, in particular comprising at least one composite material, is deposited;

[0050] iv) a vacuum step, during which the assembly obtained at the end of the step of depositing the third layer is placed under vacuum, in particular under pressure, in particular at a pressure ranging from 1.105 to 20.105 Pa;

[0051] v) a heating step, during which the assembly is heated, in particular to a temperature ranging from 100 to 200°C.

[0052] In addition, the manufacturing method according to the invention may also comprise a step of depositing a fourth layer, during which a fourth layer, in particular comprising at least a second rubber, is deposited, in particular carried out before the step of depositing a third layer.

[0053] In such an alternative, the third layer is deposited on the fourth layer.

[0054] According to another alternative, the order of the step of depositing a first layer, the step of depositing a second layer and the step of depositing a third layer can be reversed.

[0055] In other words, according to this other alternative, the method of manufacturing the multilayer material can therefore comprise the step of depositing a third layer, then the step of depositing a second layer and finally the step of depositing a first layer.

[0056] According to this other alternative, during the step of depositing a third layer, the third layer can be deposited on a support.

[0057] According to a particular embodiment, during the vacuum step, the assembly may be vacuumed to a pressure less than or equal to 500 mbar, in particular to a pressure less than or equal to 100 mbar to 500 mbar, typically to a pressure less than or equal to 400 mbar.

[0058] Advantageously, the assembly can be pressurized to a pressure ranging from 1.105 to 10.105 Pa, preferably from 4.105 to 7.105 Pa.

[0059] The present invention also relates to a fuel tank comprising at least one multilayer material according to the invention, and also an aircraft comprising a fuel tank according to the invention and / or at least one multilayer material according to the invention. Brief description of the drawings

[0060] Other aims, advantages and characteristics will emerge from the description which follows, given purely for illustrative purposes and with reference to the appended figures in which:

[0061] [Fig.lA][Fig.lB][Fig.lC][Fig.lD] schematically represent various steps for obtaining a first multilayer material according to a first embodiment in accordance with the invention;

[0062] [Fig.2A] and

[0063] [Fig.2B] schematically represent a second multilayer material according to a second embodiment in accordance with the invention; and

[0064] [Fig.3A] and

[0065] [Fig.3B] schematically represent a multilayer material according to a third embodiment in accordance with the invention.

[0066] In the present description, the limits of a domain of values, in particular introduced by the expressions “between ... and ...” and / or “... from ... to ...” are included in this domain.

[0067] Furthermore, the expression “at least one” used in the present description is equivalent to the expression “one or more”.

[0068] Furthermore, it is specified that the elongation rates, or elongation at break, are characterized in accordance with the French standard. Thus, the elongations at break, expressed in %, are measured at room temperature, and in hygrometry conditions of 50% in relative humidity rate. Detailed description of implementation methods

[0069] It should be noted that, in the figures, the structural and / or functional elements common to the different embodiments may have the same references. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

[0070] Figures 1A to 1D schematically represent various steps for obtaining a first multilayer material 1a according to a first embodiment in accordance with the invention.

[0071] More particularly, [Fig. 1D] illustrates the first multilayer material 1a according to the first embodiment according to the invention.

[0072] The first multilayer material 1a is obtained according to a production method comprising various steps described in relation to figures 1A to 1C.

[0073] The first multilayer material 1a according to a first embodiment of the invention comprises at least:

[0074] - a first layer 2, in particular composed of a first rubber comprising

[0075] * at least one diene elastomer and / or at least one thermoplastic compound,

[0076] - a second layer 3, in particular composed of a fabric comprising

[0077] * at least one fiber, in particular having a higher elongation rate or equal to 15%, and

[0078] - a third layer 4, in particular composed of a composite material, in par particular including

[0079] * a matrix, for example comprising at least one thermosetting resin, and

[0080] * a reinforcing textile, for example comprising at least one fiber, which can have an elongation rate of less than or equal to 5%.

[0081] According to the first embodiment, the first layer 2, the second layer 3 and the third layer 4 are arranged superimposed on each other, as illustrated in [Fig.1A].

[0082] In addition, according to the first embodiment, the third layer 4 may be in the form of a stack of at least two sub-layers. According to an exemplary embodiment, the third layer 4 may comprise at least:

[0083] - a first sub-layer 4a, which may in particular be a matrix sub-layer, And

[0084] - a second underlayer 4b, which may in particular be a textile underlayer reinforcement.

[0085] The third layer 4 may also be in the form of a stack of at least three sub-layers. According to an exemplary embodiment, the third layer 4 may comprise at least

[0086] - the first sub-layer 4a, which may in particular be a matrix sub-layer,

[0087] - the second underlayer 4b, which may in particular be a textile underlayer of reinforcement, and

[0088] - a third sub-layer 4c, which may in particular be a matrix sub-layer.

[0089] In the example illustrated in Figures 1A to 1D, the third layer 4 comprises the first sub-layer 4a, as matrix sub-layer, second sub-layer 4b, as reinforcing textile sub-layer, and third sub-layer 4c, as matrix sub-layer.

[0090] In the example presented, the first sub-layer 4a is an upper sub-layer, the third sub-layer 4c is a lower sub-layer and the second sub-layer 4b is arranged between the first sub-layer 4a and the third sub-layer 4c.

[0091] The first rubber of the first layer 2 is capable of ensuring sealing, and in particular also impermeability to fuel vapor, of the mul- layer, particularly as a constituent element of an aircraft fuel tank, throughout its lifetime.

[0092] According to an alternative, the first rubber may comprise at least one diene elastomer and / or at least one thermoplastic compound. The diene elastomer and the thermoplastic compound may therefore be present as a mixture.

[0093] According to a particular embodiment, the proportions by weight of the diene elastomer and the thermoplastic compound range from 50 / 50 to 90 / 10, in particular from 60 / 40 to 90 / 10, in particular from 70 / 30 to 80 / 20, and more specifically 75 / 25.

[0094] The diene elastomer may be chosen from polybutadienes, and / or butadiene copolymers and their mixtures, in particular from butadiene copolymers, in particular from butadiene and acrylonitrile copolymers.

[0095] The thermoplastic compound may be chosen from thermoplastic resins, in particular chosen from halogenated thermoplastic resins, in particular chosen from poly(vinyl tetrafluoride), poly(vinyl fluoride), poly(vinylidene chloride), poly(vinyl chloride) and / or mixtures thereof.

[0096] In the example illustrated, the first gum comprises a mixture of butadiene and acrylonitrile copolymer and poly(vinyl chloride), in particular in a weight proportion of 70 / 30.

[0097] The fabric of the second layer 3 plays an important role with regard to crash resistance. Indeed, the fabric of the second layer 3 must be able to absorb the energy induced on the tank comprising the first multilayer material 1a according to the invention resulting from a possible crash of an aircraft comprising the tank.

[0098] Advantageously, the fiber of the second layer 3 is chosen from aramid, polyamide, and / or polyester fibers.

[0099] In particular, the fiber of the second layer 3 may be chosen, taken alone or in combination, from aramid fibers, such as meta-aramid fibers, such as Nomex® or Kermel®; polyamide fibers, such as Pa 6.6 HT, in particular Enka® or Dupont® Nylon, Pa 6 HT, in particular Enkalon®, Pa 4.6 HP, in particular Stanylenka®; and polyester fibers, such as PES HT (high tenacity polyester), in particular Trevira®, Dacron®.

[0100] Standard crush-resistant flexible tanks for aircraft use are currently typically made of Type 2 yarns, most often polyamide or polyester. However, while they provide the desired crash resistance, improvements in weight are desired.

[0101] The composite material of the third layer 4 is capable of ensuring resistance to the maximum stresses, in particular mechanical stresses, experienced by an aircraft as well as to the conditions of the external environment.

[0102] Such constraints are in particular those likely to be exerted on the reservoir during a hard landing, during acceleration, or during fluid movements due to changes in the aircraft's inclination.

[0103] By “thermosetting” resin is meant a monomer, oligomer, prepolymer, polymer or any macromolecule capable of being chemically crosslinked. More particularly, it is meant a monomer, oligomer, prepolymer, polymer or any macromolecule capable of being chemically crosslinked, when it is reacted with a hardener, also called a crosslinker, in the presence of an energy source, for example a heat source or a radiation source, and possibly a catalyst.

[0104] The hardener can thus be a generally polyfunctional compound, carrying anhydride and / or acid type functions capable of reacting with reactive functions carried by the resin.

[0105] In particular, the thermosetting resin may be an epoxy resin.

[0106] There are two main categories of epoxy resins known to exist:

[0107] - glycidyl type epoxy resins, and

[0108] - non-glycidyl type epoxy resins.

[0109] Glycidyl type epoxy resins are themselves classified into glycidyl ether, glycidyl ester and glycidyl amine. Glycidyl epoxy resins are prepared by a condensation reaction of a diol, diacid or diamine with epichlorohydrin.

[0110] Non-glycidyl type epoxy resins are aliphatic or cycloaliphatic type. Non-glycidyl epoxy resins are formed by peroxidation of the olefinic double bonds of a polymer.

[0111] In the example illustrated, the reinforcing textile according to the invention is a carbon fabric.

[0112] In addition, as previously indicated, the matrix comprises at least one fiber having an elongation rate less than or equal to 5%.

[0113] Advantageously, the fiber(s) having an elongation rate of less than or equal to 5% are chosen from carbon fibers, glass fibers, aramid fibers and their mixtures.

[0114] In particular, the fiber of the third layer 4 may be chosen, taken alone or in combination, from carbon fibers, in particular high modulus carbon or high strength carbon; aramid fibers, in particular para-aramid, such as Kevlar®, Twaron® and Technora®; and glass fibers, in particular S-glass, R-glass and E-glass fibers;

[0115] In the example illustrated, the matrix of the composite material comprises a thermosetting resin chosen from epoxy resins, such as those mentioned above.

[0116] A method of manufacturing the first multilayer material 1a according to the first embodiment comprises various manufacturing steps according to the invention.

[0117] The invention relates to a method for manufacturing the multilayer material according to the invention, comprising at least:

[0118] i) a step of depositing a first layer, during which the first layer 2, in particular composed of the first rubber, is deposited, in particular on a support; and

[0119] ii) a step of depositing a second layer, during which the second layer 3, in particular composed of the fabric, is deposited, in particular on the first layer 2;

[0120] iii) a step of depositing a third layer, during which the third layer 4, in particular composed of the composite material, is deposited.

[0121] iv) a vacuum step, during which the assembly obtained at the end of the step of depositing a third layer is placed under vacuum, in particular under pressure, in particular at a pressure ranging from 1.105 to 20.105 Pa; and

[0122] v) a heating step, during which the assembly is heated, in particular to a temperature ranging from 100 to 200°C.

[0123] According to a first embodiment of the method for manufacturing the multi-layer material according to the invention, during the step of depositing a third layer, the third layer 4, in particular composed of the composite material, is deposited on the second layer 3.

[0124] Furthermore, the method of manufacturing the multilayer material according to the invention may comprise a step of depositing a fourth layer, during which the fourth layer 7, in particular composed of the second rubber, is deposited.

[0125] According to a second embodiment of the method for manufacturing the multilayer material according to the invention, the step of depositing a fourth layer is carried out before the step of depositing a third layer.

[0126] Thus, during the step of depositing a third layer, the third layer 4, notably composed of the composite material, is deposited on the fourth layer 7.

[0127] In addition, the method for manufacturing the multilayer material according to the invention may comprise a step of depositing a fifth layer, during which the fifth layer 8, in particular composed of a film, is deposited.

[0128] According to a third embodiment of the method for manufacturing the multilayer material according to the invention, the step of depositing a fifth layer is carried out before the step of depositing a third layer.

[0129] Thus, during the step of depositing a third layer, the third layer 4, notably composed of the composite material, is deposited on the fifth layer 8.

[0130] Preferably, the support is a mold. Thus, the first layer 2, the second layer 3 and the third layer 4 are deposited in a mold. Subsequently, the mold is installed in a vacuum environment.

[0131] In the example presented without limitation, the assembly composed of the first layer 2, the second layer 3 and the third layer 4 is pressurized, in particular to a pressure ranging from 4.105 Pa to 7.105 Pa.

[0132] Then, the assembly composed of the first layer 2, the second layer 3 and the third layer 4 is heated, in particular to a temperature ranging from 100°C to 200°C, in particular from 120°C to 140°C. The heating can last for a period greater than or equal to 2 hours, in particular from 2 hours to 15 hours, in particular from 2 hours to 9 hours, more specifically from 6 hours to 9 hours.

[0133] The vacuum application makes it possible in particular to drain and / or evacuate the air trapped between the first layer 2, the second layer 3 and / or the third layer 4. To this end, the pressurization compresses the first layer 2, the second layer 3 and the third layer 4, as illustrated in Figures 1B and 1C.

[0134] Thus, as illustrated in [Fig.lC], the first layer 2, the second layer 3 and the third layer 4 end up being linked to each other.

[0135] In particular, under the effect of temperature, the viscosity of the matrix and that of the first layer 2 decrease. In particular, heating corresponds to a cooking of all the elements.

[0136] At the end of the manufacturing process, the multilayer material 1a is obtained, as illustrated in [Fig. 1D].

[0137] The first multilayer material 1a comprises a first finishing zone 5, arranged between the first layer 2 and the second layer 3.

[0138] The first finishing zone 5 appears during the cooking step. Indeed, during the cooking step, the first rubber of the first layer 2 flows through the fabric of the second layer 3, such that the first finishing zone 5 is obtained, as illustrated in [Fig. 1D].

[0139] The first finishing zone 5 is important because it ensures good adhesion of the first rubber to the fabric.

[0140] In addition, in the first embodiment, the first multilayer material 1a may comprise a second finishing zone 6a. The second finishing zone 6a is disposed between the second layer 3 and the third layer 4, as illustrated in [Fig. 1D].

[0141] The second finishing zone 6a appears within the first multilayer material 1a during the baking step.

[0142] In particular, the reinforcing textile of the third layer 4, in particular of the second sub-layer 4b, ends up being in contact with the second layer 3. The matrix of the third sub-layer 4c flows through the fabric of the second layer 3, such that the second finishing zone 6a is obtained.

[0143] The second finishing zone 6a is of importance because it makes it possible to pool the functions specific to the fabric, that is to say in particular the anti- crash, and the functions specific to the composite material, in particular the matrix, i.e. the stiffness functions.

[0144] Thus, the first finishing zone 5 and the second finishing zone 6a are present within the first multilayer material 1a.

[0145] The finishing stops depending on the temperature applied, the cooking time and / or the finishing speed of the first layer 2, the second layer 3 and / or the third layer 4.

[0146] According to a particular embodiment, the composite material of the third layer 4 may have a honeycomb structure and / or a sandwich structure.

[0147] Figures 2A and 2B schematically represent various steps for obtaining a second multilayer material 1b according to a second embodiment in accordance with the invention.

[0148] More particularly, [Fig.2B] illustrates the second multilayer material 1b according to the second embodiment according to the invention.

[0149] [Fig.2A] illustrates a stacking of the layers prior to implementing a manufacturing method to obtain the second multilayer material 1b.

[0150] The second multilayer material 1b according to a second embodiment of the invention comprises at least:

[0151] - a first layer 2, in particular composed of a first rubber comprising

[0152] * at least one diene elastomer and / or at least one thermoplastic compound,

[0153] - a second layer 3, in particular composed of a fabric comprising

[0154] * at least one fiber, in particular having a higher elongation rate or equal to 15%, and

[0155] - a third layer 4, in particular composed of a composite material, in par particular including

[0156] * a matrix, for example comprising at least one thermosetting resin, and

[0157] * a reinforcing textile, for example comprising at least one fiber, which can have an elongation rate of less than or equal to 5%.

[0158] In addition, the third layer 4 also comprises

[0159] - a first sub-layer 4a, which may in particular be a matrix sub-layer,

[0160] - a second underlayer 4b, which may in particular be a textile underlayer reinforcement, and

[0161] - a third sub-layer 4c, which may in particular be a matrix sub-layer.

[0162] Furthermore, the second multilayer material 1b according to the second embodiment of the invention comprises at least:

[0163] - a fourth layer 7, in particular composed of a second rubber including

[0164] * at least one diene elastomer and / or at least one thermoplastic compound.

[0165] According to the second embodiment of the invention, the fourth layer 7 is arranged between the third layer 4 and the second layer 3.

[0166] In particular, the second rubber of the fourth layer 7 has the same characteristics and / or specificities as those described above for the first rubber of the first layer 2.

[0167] Furthermore, the second rubber of the fourth layer 7 is of the same nature as the first rubber of the first layer 2.

[0168] Furthermore, the thermoplastic compound of the second rubber of the fourth layer 7 is of the same nature as the thermoplastic compound of the first rubber of the first layer 2.

[0169] In particular, the second rubber of the fourth layer 7 and the first rubber of the first layer 2 are identical.

[0170] According to the second embodiment of the invention, the second multi-layer material 1b comprises the first finishing zone 5, as for the first multi-layer material 1a.

[0171] The second multilayer material 1b also comprises a third finishing zone 6b, arranged between the second layer 3 and the fourth layer 7.

[0172] In addition, the fourth layer 7 is arranged between the third finishing zone 6b and the third layer 4.

[0173] The method for manufacturing the second multilayer material 1b according to the second embodiment comprises at least the steps i) to v) previously described.

[0174] However, the method of manufacturing the second multilayer material 1b according to the second embodiment differs from the method of manufacturing the first multilayer material 1a of the first embodiment by the presence of the second rubber of the fourth layer 7.

[0175] It is during the baking step that the finishing layers are formed within the second multilayer material 1b, according to the same principle as for the first multilayer material 1a.

[0176] The third finishing zone 6b appears during the cooking step. Indeed, during the cooking step, the second rubber of the fourth layer 7 flows through the fabric of the second layer 3, so that the third finishing zone 6b is obtained.

[0177] The third finishing zone 6b is of importance because it makes it possible to pool the functions specific to the fabric, i.e. in particular the anti-crash functions and the functions specific to the second rubber and to the composite material, in particular the matrix, i.e. the rigidity functions.

[0178] More particularly, the fourth layer 7 can act as a fuse. Thus, if the forces are too great, the fourth layer 7 is likely to deteriorate without deteriorate the anti-crash properties of the second layer fabric 3.

[0179] Other embodiments of the multilayer material according to the invention may be described.

[0180] In particular, at least one thin film can be inserted between the second layer 3 and the third layer 4 before proceeding with the step of depositing a third layer and / or the step of depositing a fourth layer.

[0181] Figures 3A and 3B schematically represent various steps for obtaining a third multilayer material according to a third embodiment in accordance with the invention.

[0182] More particularly, [Fig.3B] illustrates the third multilayer material 1c according to the third embodiment of the invention.

[0183] [Fig.3A] illustrates a stacking of the layers prior to implementing a manufacturing process to obtain the third multilayer material 1e.

[0184] The third multilayer material according to the third embodiment of the invention comprises at least:

[0185] - a first layer 2, in particular composed of a first rubber comprising

[0186] * at least one diene elastomer and / or at least one thermoplastic compound,

[0187] - a second layer 3, in particular composed of a fabric comprising

[0188] * at least one fiber, in particular having a higher elongation rate or equal to 15%, and

[0189] - a third layer 4, in particular composed of a composite material, in par particular including

[0190] * a matrix, for example comprising at least one thermosetting resin, and

[0191] * a reinforcing textile, for example comprising at least one fiber, which may have an elongation rate of less than or equal to 5%.

[0192] In addition, layer 4 also comprises

[0193] - a first sub-layer 4a, which may in particular be a matrix sub-layer,

[0194] - a second underlayer 4b, which may in particular be a textile underlayer reinforcement, and

[0195] - a third sub-layer 4c, which may in particular be a matrix sub-layer.

[0196] Furthermore, the third multilayer material according to the third embodiment of the invention comprises at least:

[0197] - a fifth layer 8, in particular composed of a film, in particular a thin film perforated.

[0198] According to the third embodiment of the invention, the fifth layer 8 is arranged between the third layer 4 and the second layer 3.

[0199] The fifth layer 8 may be a film, for example a fluorinated film, a high-performance semi-crystalline fluorinated polymer film or a polyamide film.

[0200] In addition, the fifth layer 8 may be perforated, so as to decrease a bonding surface of the composite matrix through the fabric.

[0201] According to the third embodiment of the invention, the third multi-layer material 1a comprises the first finishing zone 5, as for the first multi-layer material 1a.

[0202] The third multilayer material 1c also comprises a fourth finishing zone 6c, arranged between the second layer 3 and the fifth layer 8.

[0203] In addition, the fifth layer 8 is arranged between the fourth finishing zone 6c and the third layer 4.

[0204] The method for manufacturing the third multilayer material according to the third embodiment comprises at least steps i) to v) previously described.

[0205] However, the method of manufacturing the third multilayer material 1c according to the third embodiment differs from the method of manufacturing the first multilayer material 1a of the first embodiment by the presence of the fifth layer 8.

[0206] It is during the baking step that the finishing layers are formed within the third multi-layer material 1c, according to the same principle as for the first multi-layer material 1a.

[0207] The fourth finishing zone 6c appears during the baking step. Indeed, during the baking step, the matrix of the third sub-layer 4c flows through the fifth layer 8 so that the fourth finishing zone 6c is obtained.

[0208] Other embodiments of the multilayer material according to the invention may be described, in particular comprising one or more additional layers of fabric.

[0209] The invention also relates to a method of manufacturing the multilayer material according to the invention as described previously.

[0210] The invention also relates to a fuel tank comprising at least one multilayer material according to the invention and also an aircraft comprising a fuel tank according to the invention and / or at least one multilayer material according to the invention.

[0211] Advantageously, the multilayer material according to the invention can be used as a wall of the fuel tank.

[0212] Preferably, the first layer 2 occupies an inner side of the fuel tank wall and the third layer 4 occupies an outer side of the fuel tank wall.

[0213] In other words, according to such a configuration, the first layer 2 has a surface oriented towards the inside of the fuel tank and the third layer 4 has a surface oriented towards the outside of the fuel tank.

[0214] The manufacturing method according to the invention therefore allows an assembly of each elements and cooking of the assembly made up of such elements. The manufacturing method according to the invention therefore makes it possible to pool all the functions of each of the elements, in particular the structural and anti-crash functions, to obtain a particularly advantageous multi-layer material.

[0215] The multilayer material according to the invention is in fact lighter and retains all the mechanical properties required for a fuel tank, in particular for an aircraft.

[0216] The multilayer material according to the invention also makes it possible to do away with the attachment devices currently used to link the flexible walls to the rigid boxes.

Claims

Claims

1. Multilayer material (la, 1b, 1c) comprising at least: - a first layer (2), - a second layer (3), and - a third layer (4), characterized in that it comprises a first finishing zone (5) of at least a part of the first layer (2) through at least a part of the second layer (3).

2. Multilayer material (la, 1b, 1c) according to claim 1, characterized in that it comprises a second finishing zone (6a) of at least a part of the second layer (3) through at least a part of the third layer (4).

3. Multilayer material (la, 1b, 1c) according to claim 1, characterized in that it comprises a fourth layer (7) arranged between the second layer (3) and the third layer (4).

4. Multilayer material (la, 1b, 1c) according to claim 3, characterized in that it comprises at least a third finishing zone (6b) of at least a part of the fourth layer (7) through at least a part of the second layer (3).

5. Multilayer material (la, 1b, 1c) according to claim 3 or 4, characterized in that the fourth layer (7) comprises at least one second rubber, in particular comprising at least one diene elastomer and / or at least one thermoplastic compound.

6. Multilayer material (la, 1b, le) according to claim 1 or 3, characterized in that it comprises a fifth layer (8) arranged between the third layer (4) and the second layer (3) or the fourth layer (7).

7. Multilayer material (la, 1b, 1c) according to claim 6, characterized in that it comprises at least a fourth creep zone (6c) of at least a part of the third layer (4) through at least a part of the fifth layer (8).

8. Multilayer material (la, 1b, 1c) according to any one of the preceding claims, characterized in that the first layer (2) comprises at least one first rubber, in particular comprising at least one diene elastomer and / or at least one thermoplastic compound.

9. Multilayer material (la, 1b, 1c) according to claim 5 or 8, ca- characterized in that the diene elastomer is chosen from polybutadienes, butadiene copolymers and their mixtures, in particular from butadiene copolymers, in particular from butadiene and acrylonitrile copolymers, and / or in that the thermoplastic compound is chosen from halogenated thermoplastic resins, in particular poly(vinyl tetrafluoride), poly(vinyl fluoride), poly(vinylidene chloride) and / or poly(vinyl chloride).

10. Multilayer material (la, 1b, 1c) according to any one of the preceding claims, characterized in that the second layer (3) comprises at least one fabric, in particular comprising at least one fiber, in particular having an elongation rate greater than or equal to 15%.

11. Multilayer material (la, 1b, 1c) according to any one of the preceding claims, characterized in that the third layer (4) comprises at least one composite material comprising: - a reinforcing textile, in particular comprising at least one fiber, having an elongation rate of less than or equal to 5%, in particular a carbon fiber, an aramid fiber and / or a glass fiber and - a matrix, in particular comprising at least one thermosetting resin, in particular an epoxy resin.

12. Fuel tank comprising at least one multilayer material (la, 1b, 1c) according to any one of the preceding claims.

13. Aircraft comprising a fuel tank according to claim 12 and / or at least one multilayer material (la, 1b, 1c) according to any one of claims 1 to 11.

14. Method for manufacturing a multilayer material (la, 1b, 1c) according to any one of claims 1 to 11, comprising at least: i) a step of depositing a first layer, during which a first layer (2), in particular comprising at least one first rubber, is deposited, in particular on a support; and ii) a step of depositing a second layer, during which a second layer (3), in particular comprising at least one fabric, is deposited, in particular on the first layer (2); iii) a step of depositing a third layer, during which a third layer (4), in particular comprising at least one composite material, is deposited; iv) a vacuum step, during which the assembly obtained at the end of the step of depositing the third layer (4) is placed under vacuum, in particular under pressure, in particular at a pressure ranging from 1.105 to 20.105 Pa; and (v) a heating step, during which the assembly is heated, in particular to a temperature ranging from 100 to 200°C.

15. Manufacturing method according to claim 14, characterized in that it comprises a step of depositing a fourth layer (7), during which the fourth layer (7), in particular comprising at least a second rubber, is deposited, in particular carried out before the step of depositing a third layer (4).

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