MULTILAYER STRUCTURE FOR TRANSPORTING OR STORING HYDROGEN

Abstract

A multilayer structure, intended for the transportation, for the distribution or for the storage of a gas, in particular hydrogen, including, from the inside toward the outside, N composite reinforcing layer(s), deposited on one another, and being of a fibrous material in the form of continuous fibers which is impregnated by a composition of at least one semicrystalline thermoplastic polymer P1, the M.p. of which, as measured according to ISO 11357-3:2013, is greater than or equal to 150? C., or at least one amorphous thermoplastic polymer, the Tg of which is greater than 80? C., N being of from 1 to 2000 layers, and an outer sealing layer (1) cohesive with the outermost composite reinforcing layer (2) and including a composition of the at least one thermoplastic polymer P1, the composition of the outer sealing layer (1) resulting from at least the outermost composite reinforcing layer (2) cohesive with the sealing layer.

Claims

1. A multilayer structure chosen from a tank, a pipe and a tube, configured for the transportation, for the distribution or for the storage of a gas, comprising, from the inside toward the outside, N composite reinforcing layer(s) (2), deposited on one another, and consisting of a fibrous material in the form of continuous fibers which is impregnated by a composition comprising predominantly at least one semicrystalline thermoplastic polymer P1, the M.p. of which, as measured according to ISO 11357-3:2013, is greater than or equal to 150? C., or at least one amorphous thermoplastic polymer, the Tg of which is greater than 80? C., N being of from 1 to 2000 layers, and an outer sealing layer (1) cohesive with the outermost composite reinforcing layer (2) and consisting of said composition comprising predominantly said at least one thermoplastic polymer P1, polypropylene being excluded from said semicrystalline thermoplastic polymer P1, said composition of the outer sealing layer (1) resulting from at least the outermost composite reinforcing layer (2), said outer sealing layer (1) exhibiting a thickness of at least 5 ?m, the sum of the thicknesses of each composite reinforcing layer (2) and of the thickness of the outer sealing layer (1) being equal to the sum of the thicknesses of said N layers before deposition, minus possible porosities.

2. The multilayer structure as claimed in claim 1, wherein each composite reinforcing layer (2) consists, before deposition, of said impregnated fibrous material in the form of continuous fibers exhibiting an initial content of fibers of from 45% to 65% by volume.

3. The multilayer structure as claimed in claim 1, wherein each composite reinforcing layer (2) consists, after deposition, of said impregnated fibrous material in the form of continuous fibers exhibiting a content of fibers of from 50% to 70% by volume.

4. The multilayer structure as claimed in claim 1, wherein the residual porosities, when they are present, of said composite reinforcing layers are decreased by at most 90%.

5. The multilayer structure as claimed in claim 1, wherein the total thickness, corresponding to the sum of the thicknesses of each composite reinforcing layer (2) after deposition and of the thickness of the outer sealing layer, is equal to N?the initial thickness (Th.sub.i) of each composite reinforcing layer (2) before deposition, minus possible porosities.

6. The multilayer structure as claimed in claim 5, wherein the thickness of the sealing layer is of from:
5 ?m to [(1?(T.sub.min before deposition/T.sub.max after deposition))?N?Th.sub.i?(1?x %)]?m in which: T.sub.min before deposition represents the minimum content of fibers by volume before deposition, T.sub.max after deposition represents the maximum content of fibers by volume in the reinforcing layer after deposition, N represents the number of reinforcing layers, and Th.sub.i represents the initial thickness of the impregnated fibrous material before deposition, x % the content of porosities in the initial tape before deposition.

7. The multilayer structure as claimed in claim 1, wherein said structure furthermore comprises at least one inner sealing layer (3), located under the innermost composite reinforcing layer (2), and consisting of a composition comprising predominantly at least one semicrystalline thermoplastic polymer P2 or made of composite material and consisting of fibers impregnated with a composition comprising predominantly at least one semicrystalline thermoplastic polymer P2, the M.p. of said semicrystalline thermoplastic polymer P2, as measured according to ISO 11357-3:2013, being less than 300? C., said innermost inner sealing layer (3) being in contact with the gas.

8. The multilayer structure as claimed in claim 7, wherein said innermost composite reinforcing layer (2) is welded to said adjacent outermost inner sealing layer (3).

9. The multilayer structure as claimed in claim 1, wherein said structure is devoid of an inner sealing layer (3) located under the innermost composite reinforcing layer (2), said innermost composite reinforcing layer (2) being in contact with the gas.

10. The multilayer structure as claimed in claim 1, wherein the number-average molecular weight Mn of said thermoplastic polymer P1 is of from 11,000 to 40,000 g/mol.

11. The multilayer structure as claimed in claim 1, wherein said gas is hydrogen and the total proportion of extracted contaminants in the hydrogen is less than or equal to 3% by weight, of the sum of the constituents of said composition impregnating said fibrous material or of the composition constituting said inner sealing layer (3), as determined by a test of contaminants present in the hydrogen and extracted from said composite reinforcing layer (2) or from said inner sealing layer (3) after contact of the hydrogen with this, said test being carried out as defined in the standard CSA/ANSI CHMC 2:19.

12. The multilayer structure as claimed in claim 1, wherein said structure is chosen from a cylindrical tank, a polymorphic tank, a bendable pipe and a bent pipe.

13. The multilayer structure as claimed in claim 1, wherein said at least one thermoplastic polymer P1 is a reactive polymer or a nonreactive polymer.

14. The multilayer structure as claimed in claim 1, wherein said at least one thermoplastic polymer P1 is selected from: polyaryl ether ketones (PAEKs); polyaryl ether ketone ketones (PAEKKs); aromatic polyetherimides (PEIs); polyaryl sulfones; polyaryl sulfides; polyamides (PAs); polyolefins, with the exclusion of polypropylene; polylactic acid (PLA); polyvinyl alcohol (PVA); fluoropolymers; and their mixtures.

15. The multilayer structure as claimed in claim 14, wherein said at least one thermoplastic polymer P1 is selected from polyamides, PEKK, PEI and a mixture of PEKK and of PEI.

16. The multilayer structure as claimed in claim 14, wherein said polyamide is chosen from aliphatic polyamides, cycloaliphatic polyamides and semiaromatic polyamides (polyphthalamides).

17. The multilayer structure as claimed in claim 16, wherein said aliphatic polyamide is chosen from polyamide 6 (PA6), polyamide 11 (PA11), polyamide 12 (PA12), polyamide 66 (PA66), polyamide 46 (PA46), polyamide 610 (PA610), polyamide 612 (PA612), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 11/1010 (PA11/1010) and polyamide 12/1010 (PA12/1010), or a blend of these or a copolyamide of these, and block copolymers, and said semiaromatic polyamide is a semiaromatic polyamide, optionally modified by urea units, or a semiaromatic polyamide of formula X/Yar.

18. The multilayer structure as claimed in claim 1, wherein said fibrous material comprises continuous fibers selected from carbon fibers, glass fibers, silicon carbide fibers, basalt fibers, basalt-based fibers, silica fibers, natural fibers, or amorphous thermoplastic fibers with a glass transition temperature Tg greater than the Tg of said polymer or of said blend of polymers when the latter is amorphous or greater than the M.p. of said polymer or of said blend of polymers when the latter is semicrystalline, or semicrystalline thermoplastic fibers with a melting point M.p. greater than the Tg of said polymer or of said blend of polymers when the latter is amorphous or greater than the M.p. of said polymer or of said blend of polymers when the latter is semicrystalline, or a mixture of two or more of said fibers.

19. The multilayer structure as claimed in claim 1, wherein said structure furthermore comprises at least one outer layer (4), said layer being the outermost layer of said multilayer structure.

20. The multilayer structure as claimed in claim 1, wherein the fibrous material is chosen from glass fibers, carbon fibers, basalt fibers and basalt-based fibers.

21. A process for the manufacture of a multilayer structure as defined in claim 1, wherein the process comprises a stage of deposition of at least one band of fibrous material impregnated with a thermoplastic polymer on a support, in order to form a composite reinforcing layer N, by means of a main heating system chosen from: a system (1) for preheating said impregnated band of fibrous material before deposition of said band on said support, and a system for heating said impregnated band of fibrous material on its inner face (2) at the point of contact of said band with said support, in combination with at least one secondary heating system making it possible for the composite reinforcing layer (2) N?1 on which the layer N will be deposited to be at a temperature greater than the M.p. of said thermoplastic polymer at the moment of contact of said layer N with said layer N?1.

22. The process as claimed in claim 21, wherein the secondary heating is chosen from the following: a system for heating said impregnated band of fibrous material on its outer face (3) at the point of contact of said band with said support, a system (4) for postheating said impregnated band n of fibrous material after deposition of said band n on said support, a system (5) for heating said support, and a system (6) for preheating the impregnated band n?1 of fibrous material previously deposited before deposition of said band n of fibrous material, it being possible for said systems 4 and 6 to be combined.

23. The process as claimed in claim 22, wherein said at least one main and secondary heating system is chosen from a heat-transfer fluid, induction heating, direct current, a heating cartridge, a heating press roller, a light-emitting diode (LED), infrared (IR), a UV source, hot air and a laser, it being possible for said primary and secondary heating systems to be identical or different.

24. The multilayer structure as claimed in claim 1, wherein N is from 2 to 2000 layers.

25. The multilayer structure as claimed in claim 1, wherein the outer sealing layer (1) has a thickness of at least 10 ?m.

Description

DESCRIPTION OF THE FIGURES

[0259] FIG. 1 exhibits the various possible heating systems (2), (3), (4) and (6) on a cylindrical support seen in cross section exhibiting an optional heating system (5).

[0260] FIG. 2 exhibits the various possible combined heating systems (4) and (6) on a cylindrical and rotary support optionally exhibiting a heating system (5).

[0261] FIG. 3 exhibits the various systems for heating by laser (2) and heating press roller (3) on a rotary cylindrical support exhibiting a heating system (5) (heating mandrel).

[0262] FIG. 4 exhibits the micrograph of a tank of the invention obtained with bands of example 1 comprising a sealing layer (1) and composite reinforcing layers (2).

EXAMPLES

Example 1: Preparation of Bands of Fibrous Material

[0263] The bands of fibrous material were prepared according to WO2018/234436: example 2 (band of fibrous material (carbon fiber, SGL, 24K, reference C T24-5.0 270-T140), monolayer impregnated with PA11) and example 5 for the degree of porosity. A mean thickness of these tapes at 250 ?m and a degree of porosity of approximately 3% are measured.

[0264] The content of fibers by volume of the band of impregnated fibrous material obtained is 45% vCF, its melting point is 190? C., its M.p..sub.endset is 200? C. and its Tg is at 50? C. The Tc of this polymer is equal to 150? C.

Example 2: Preparation of a Tank of the Invention with the Bands of Fibrous Material of Example 1

[0265] The bands of prepregs obtained are placed on a creel making it possible to manage the mechanical tension of unwinding these reels of prepregs. An unwinding tension is set at 50N for each of the 3 bands which are unwound in parallel.

[0266] These 3 bands progress forward at a speed of 30 m/min under infrared (IR) radiating devices with a total length of 150 cm and with a maximum power of 50 kW. The power of these infrared devices is regulated and self-regulated via a temperature measurement on the prepreg bands (by virtue of an IR pyrometer placed at halfway under the IR devices and a control thermal camera at the heating medium outlet) in order to ensure that, at the outlet of this heating medium, the bands are at a temperature above the melting point. In this example, a temperature of 230? C. exists at the hottest point.

[0267] The bands are then guided via ceramic guides to prevent them from deviating from their deposition path.

[0268] They are then deposited on the cylindrical metal winding support, with a diameter of 300 mm, which is itself placed on a 6-axis robot. The bands progress forward and are pulled up to the deposition support by virtue of the rotational force of the metal mandrel which constitutes the winding support.

[0269] At the moment of the deposition of the layer N, the reinforcing layer N-1 already deposited is brought to a temperature greater than M.p. (in this instance 210? C.) by virtue of IR emitters placed circumferentially around the cylinder acting as deposition support and being integrally attached to the structure of the robotic arm. These IR emitters have a maximum power of 25 kW each and are 3 in number, for a length of emitters of 120 cm each. They are placed beside one another so as to heat only the layer N?1 over its working zone before deposition of the layer N. In order to limit heat losses and thus promote the migration of the resin during the deposition toward the outer layer, a heating mandrel maintained at 160? C. throughout the test is used.

[0270] The creation of a dense layer of PA11 at the outer surface of this tank section with a thickness of 450 ?m is observed. This dense layer, free from carbon fiber, results from the migration/wringing/flowing of molten PA11 under the effect of the pressure and of the temperature of deposition of the three tapes deposited in parallel during the manufacture of the tank which comprises, in the context of this example, 8 superimposed layers of reinforcements.

[0271] It is subsequently measured, by image analysis, that the content of fibers in the dense homolytic layers of the mechanically strong part of the tank has changed from 45% vCF (initial tape) to 58.5% vCF in the monolithic part created from the internal part of the tank up to the polymer-rich layer.

Example 3: Determination of the Degree of Porosity by the Relative Deviation Between Theoretical Density and Experimental Density (General Method)

[0272] a) The Data Required are: [0273] The density of the thermoplastic matrix [0274] The density of the fibers [0275] The basis weight of the reinforcement: [0276] linear density (g/m), for example for a 1/4 inch tape (resulting from a single roving) [0277] surface density (g/m2), for example for a wider tape or a woven fabric

[0278] b) Measurements to be Carried Out:

[0279] The number of samples must be at least 30 in order for the result to be representative of the material studied.

[0280] The measurements to be carried out are: [0281] The size of the samples withdrawn: [0282] Length (if linear density known), [0283] Length and width (if surface density known). [0284] The experimental density of the samples withdrawn: [0285] Measurements of weight in air and in water. [0286] The measurement of the content of fibers is determined according to ISO 1172:1999 or by thermogravimetric analysis (TGA) as determined, for example, in the document B. Benzler, Applikationslabor, Mettler Toledo, Giesen, UserCom 1/2001.

[0287] The measurement of the content of carbon fibers can be determined according to ISO 14127:2008.

[0288] Determination of the Theoretical Content of Fibers by Eeight:

[0289] a) Determination of the Theoretical Content of Fibers by Weight:

[00001]$\begin{array}{cc}\%{\mathrm{Wft}}_h=\frac{d_l.L}{{\mathrm{Ws}}_{\mathrm{air}}}& \left[\mathrm{Math}3\right]\end{array}$ [0290] with [0291] d1 the linear density of the tape, [0292] L the length of the sample and [0293] Ws.sub.air the weight of the sample measured in air.

[0294] The variation in the content by weight of fibers is assumed to be directly linked to a variation in the content of matrix without taking into account the variation in the amount of fibers in the reinforcement.

[0295] b) Determination of the Theoretical Density:

[00002]$\begin{array}{cc}d\text{?}=\frac{1}{\frac{1-\%{\mathrm{Wf}}_{\mathrm{th}}}{d_m}+\frac{\%{\mathrm{Wf}}_{\mathrm{th}}}{d_f}}& \left[\mathrm{Math}4\right]\end{array}$$\text{?}\text{indicates text missing or illegible when filed}$

with d.sub.m and d.sub.f the respective densities of the matrix and of the fibers.

[0296] The theoretical density thus calculated is the accessible density if there is no porosity in the samples.

[0297] c) Evaluation of the Porosity:

[0298] The porosity is then the relative deviation between theoretical density and experimental density.