Multilayer structure for transporting or storing hydrogen

1. A multilayer structure intended for transporting, distributing, or storing hydrogen, comprising, from the inside to the outside, at least one sealing layer and at least one composite reinforcement layer,

said innermost composite reinforcement layer being wound around said outermost adjacent sealing layer,

said sealing layers consisting of a composition comprising:

more than 50% by weight relative to the total weight of the composition of at least one long-chain polyamide thermoplastic polymer P1i, i=1 to n, n being the number of sealing layers, semi-crystalline including the Tm, as measured according to ISO 11357-3:2013, is greater than 160° C.,

said long-chain polyamide thermoplastic polymer having an average number of carbon atoms per nitrogen atom greater than 9,

excluding a polyether block amide (PEBA),

up to 50% by weight of impact modifier relative to the total weight of the composition,

up to 1.5% by weight of plasticizer relative to the total weight of the composition,

said composition being devoid of nucleating agent,

said at least one predominant polyamide thermoplastic polymer in each sealing layer that may be the same or different,

and at least one of said composite reinforcement layers consisting of a fibrous material in the form of continuous fibers, which is impregnated with a composition comprising more than 50% by weight, relative to the total weight of the composition, of at least one polymer P2j, j=1 to m, m being the number of reinforcement layers, said structure being devoid of a polyamide polymer layer, said polyamide polymer layer being the outermost and adjacent to the outermost layer of composite reinforcement.

2. The multilayer structure according to claim 1 , wherein each sealing layer comprises the same type of polyamide.

3. The multilayer structure according to claim 1 , wherein each reinforcement layer comprises the same type of polymer.

4. The multilayer structure according to claim 3 , wherein each sealing layer comprises the same type of polymer and each reinforcement layer comprises the same type of polymer.

5. The multilayer structure according to claim 1 , wherein it has a single sealing layer and a single reinforcement layer.

6. The multilayer structure according to claim 1 , wherein said polymer P1i is a long-chain aliphatic polyamide, or semi-aromatic.

7. The multilayer structure according to claim 1 , wherein said polymer P2j is an epoxy resin or epoxy-based resin.

8. Multilayer structure according to claim 6 , wherein said multilayer structure consists of a single reinforcement layer and a single sealing layer in which said polymer P1i is a long-chain aliphatic polyamide, or semi-aromatic, the MXDT/10T, the MPMDT/10T and the BACT/10T.

9. The multilayer structure according to claim 1 , wherein the fibrous material of the composite reinforcement layer is selected from glass fibers, carbon fibers, basalt fibers or basalt-based fibers, or a mixture thereof.

10. The multilayer structure according to claim 1 , wherein said structure further comprises at least one outer layer consisting of a fibrous material made of continuous glass fibers, which is impregnated with a transparent amorphous polymer, said layer being the outermost layer of said multilayer structure.

11. A method for producing a multilayer structure as defined in claim 1 , wherein it comprises a step of preparing the sealing layer by extrusion blow molding, rotational molding, injection molding and/or extrusion.

12. The method for producing a multilayer structure as defined in claim 11 , wherein it comprises a step of filament winding of the reinforcement layer around the sealing layer.