Fast-setting composition for the manufacture of semi-finished products enabling the manufacture of composite type IV pressure tanks for on-board storage of hydrogen gas

Abstract

The present invention relates to a composition (C) comprising (A) 70 to 95 parts by weight of an epoxide resin having a viscosity of 1 kPa·s to 150 kPa·s at a temperature of 20° C. to 25° C. and (B) a curing agent dispersed in 5 to 30 parts by weight of the resin per 100 parts by weight of the resin present in the composition, the curing agent being an ionic liquid containing a phosphonium cation. The present invention also relates to a bundle of fibers (F) and a semi-finished product or towpreg comprising the composition (C). The present invention also relates to the use of the composition (C) or the semi-finished product according to the invention for the manufacture of a hydrogen tank, in particular a type IV pressure tank, made of the composite material for the on-board storage of hydrogen gas.

Description

[Technical field]

[0001] The present invention relates to the field of manufacture of Type IV pressure vessels made from composite materials for the storage of gaseous hydrogen for both stationary and mobile applications, such as hydrogen storage infrastructure, transportation of hydrogen for refueling, hydrogen rail cars, buses, trucks, planes, boats and other hydrogen vehicles, and hydrogen automobiles. [Background technology]

[0002] Currently, on-board systems exist for the storage of gaseous hydrogen in pressure vessels for transport applications, but there are only a few manufacturers selling thousands of approved vessels per year. With the emergence of markets related to low-carbon mobility and pressure storage, there is no suitable supply chain (conversion of raw materials and components into finished products delivered to end customers) for mass production (millions of units per year) at reasonable cost. For example, compact, reliable, safe and economical storage of hydrogen gas below 700 bar is a major challenge for the widespread commercialization of fuel cell electric vehicles (FCEVs) and other fuel cell applications. Although several lightweight FECVs with ranges of over 500 km have appeared since 2015, on-board hydrogen storage at low cost remains a major obstacle and the production volumes of vessels remain low. Most of the efforts in hydrogen storage programs are focused on developing cost-effective hydrogen storage technologies with improved energy density (gravimetric capacity close to 6%, i.e. 6% of the mass of the storage system is hydrogen).

[0003] Hydrogen containers for cars, buses, trucks, trains, planes and boats already exist, but they have not yet met all of the expectations of manufacturers in terms of mass production of hydrogen-powered systems, not only in terms of the manufacture of H2 containers, but also in terms of the deployment and use of fuel cell vehicles.

[0004] Although the manufacturing cost of a Type IV pressure vessel made from composite materials for on-board storage of gaseous hydrogen is only about 10%-30% of the cost of the storage system, mass production capacity is a major challenge for automotive integrators. The polymerization (or curing) step of the composite matrix, which ensures resistance to high pressures, is currently the main step limiting the rate at which the vessel can be manufactured. The composite matrix of a composite pressure vessel is typically an epoxy matrix.

[0005] To meet the production needs of millions of vehicles per year, the polymerization (or cure) time of the composite matrix of Type IV containers must be significantly reduced.

[0006] Currently, for epoxy matrices, the polymerization (or curing) process time in a 700 bar pressure vessel is approximately 12 to 16 hours, which is too long for mass production such as that required by the automotive industry. Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, there is a real need to make the manufacture of Type IV pressure vessels made from composite materials for on-board storage of gaseous hydrogen efficient and industrially suitable for mass production.

[0008] In particular, there is a real need to significantly reduce the time of the polymerization (or curing) step of the composite matrix in order to minimize the cycle time for manufacturing the container. [Means for solving the problem]

[0009] To achieve this, the present invention proposes a novel composition for a composite material that takes into account the technical and regulatory limitations associated with high pressure composite vessels for on-board hydrogen storage.

[0010] The present invention relates to a composition (C), (A) 70 parts by mass to 95 parts by mass of an epoxy resin having a viscosity of 1 Pa s to 150 kPa s at a temperature of 20°C to 25°C; (B) a curing agent dispersed in a resin in an amount of 5 to 30 parts by mass per 100 parts by mass of the resin present in the composition; and the curing agent is of the formula P(R1R2R3R4) + (wherein R1, R2, R3 and R4 are the same or different and represent a hydrogen atom, an alkyl radical having 1 to 18 carbon atoms, or an aryl radical having 6 to 20 carbon atoms, and the alkyl radical and aryl radical are optionally substituted),

[0011] Type IV high pressure vessels made from composite materials, called bladder or liner, comprise an internal layer of polymeric material, generally thermoplastic, with metal connectors, called bosses, at one or both ends. The bosses provide the connection between the vessel and the storage system. The liner provides the hydrogen tightness. This assembly is covered with a structuring composite material that ensures structuring under internal pressure, usually comprising a thermosetting matrix, generally an epoxy resin, and a reinforcement material, generally based on long fibers, for example carbon or glass fibers.

[0012] The present invention therefore aims to support the development of an on-board storage system of gaseous hydrogen in reinforced pressure vessels (CGH2 compressed gaseous hydrogen, CPV composite pressure vessel), in order to anticipate the future mass deployment of the above mentioned technology, by focusing in particular on the composition of the composite material of the vessel, more precisely on the resin and its polymerization reactions, which greatly influence the production rate, over a period generally exceeding 10 hours.

[0013] The compositions of the invention are particularly advantageous due to their rapid polymerization (or curing) compared to currently used compositions based on epoxy matrices, in particular due to the use of phosphorus ionic liquids as hardeners. Indeed, the polymerization (or curing) time of the epoxy matrix in the compositions according to the invention is less than 12 hours, less than 10 hours, in particular less than 8 hours, more particularly less than 6 hours.

[0014] Another object of the present invention is to provide A fiber bundle (F) selected from carbon fiber, glass fiber, aramid fiber, silicon carbide fiber, and organic fiber; A composition (C) according to the present invention, The fiber bundle is impregnated with the composition, This is a semi-finished product called a towpreg, characterized in that the volume content of (F) is 40% to 70% and the volume content of (C) is 30% to 60%.

[0015] The fibre bundles may be in the form of sheets or aggregates of non-woven loose fibres, or in a woven form.

[0016] The semi-finished product or towpreg can be polymerized after impregnation of the fibers (F) with the composition (C).

[0017] The semi-finished product or towpreg may be optionally wound onto a spool after impregnation of the fibers (F) with the composition (C) and after its polymerization (or curing).

[0018] The compositions (C) and semi-finished products or towpregs according to the invention can be used in particular for the manufacture of type IV pressure vessels made from the composite material for both stationary and mobile applications, such as hydrogen storage infrastructure, transportation of hydrogen for refueling, hydrogen rail cars, buses, trucks, planes, boats and other hydrogen vehicles, and on-board storage of gaseous hydrogen for hydrogen automobiles.

[0019] Another object of the invention is the use of the composition (C) or a semi-finished product according to the invention for the manufacture of hydrogen containers, in particular type IV pressure containers, made from composite materials for the on-board storage of gaseous hydrogen.

[0020] Another object of the invention is a structure made from a composite material that includes a polymeric semi-finished product or towpreg.

[0021] More specifically, the structure is a pressure vessel.

[0022] The vessel is preferably a Type IV pressure vessel for on-board storage of gaseous hydrogen.

[0023] The present invention also relates to a method for producing a hydrogen container, in particular a Type IV pressure container, which comprises the steps of achieving a desired shape of an unpolymerized composition according to the invention, and then polymerizing the composition in the desired shape.

[0024] However, an alternative method for producing hydrogen containers according to the invention, in particular Type IV pressure containers, involves achieving the desired shape of an already polymerized composition according to the invention.

[0025] A further method for producing a hydrogen container according to the invention, in particular a type IV pressure container, comprises the steps of achieving the desired shape of a semi-finished product according to the invention and then polymerizing the shaped semi-finished product. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The present invention relates to a composition (C), which comprises (A) 70 parts by mass to 95 parts by mass of an epoxy resin having a viscosity of 1 Pa s to 150 kPa s at a temperature of 20°C to 25°C; (B) a curing agent dispersed in a resin in an amount of 5 to 30 parts by mass per 100 parts by mass of the resin present in the composition; The present invention is characterized in that it comprises The curing agent has the formula P(R1R2R3R4) + (wherein R1, R2, R3 and R4 are the same or different and represent a hydrogen atom, an alkyl radical having 1 to 18 carbon atoms, or an aryl radical having 6 to 20 carbon atoms, and the alkyl radical and aryl radical are optionally substituted).

[0027] The term "alkyl" according to the present invention means a linear, branched or cyclic saturated, optionally substituted carbon radical containing 1 to 18 carbon atoms, such as 1 to 14 carbon atoms, such as 1 to 12 carbon atoms, such as 1 to 6 carbon atoms. Examples of saturated linear or branched alkyls include the radicals methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, nonyl, decyl, undecyl (C 11 , dodecanyl (or dodecyl (C 12 )), tridecyl (C 13 ), tetradecyl (C 14 ) and their branched isomers. Examples of cyclic alkyl include the radicals cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, bicyclo[2,1,1]hexyl, and bicyclo[2,2,1]heptyl.

[0028] The term "aryl" refers to a monocyclic or polycyclic aromatic substituent containing 6 to 20 carbon atoms, for example 6 to 10 carbon atoms. By way of illustration, examples include phenyl, benzyl, naphthyl and phenanthrenyl groups.

[0029] The alkyl and aryl radicals may be optionally substituted with one or more hydroxy groups (-OH), one or more alkoxy groups (-O-alkyl), one or more aryloxy groups (-O-aryl), one or more halogen atoms selected from among fluorine, chlorine, bromine and iodine atoms, where alkyl and aryl are defined in the context of the present invention.

[0030] In one embodiment, in the phosphonium cation, R1, R2, R3 and R4 are the same or different, Hydrogen atoms, Alkyl radicals selected from among methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl and branched isomers thereof; an aryl radical selected from among phenyl, benzyl, The alkyl and aryl radicals are optionally substituted.

[0031] The phosphonium cation is PH4 + , P(CH3)4 + , P(Ph)4 + , P(CH3)(Ph)3 + , P(CH2OH)4 + You can choose from among:

[0032] The phosphonium cation also reacts with PH4 + , P(CH3)4 + , P(Ph)4 + , P(CH3)(Ph)3 + , P(CH2OH)4 + , P(CH 13 )3(C 14 H 29 ) + You can choose from among:

[0033] More specifically, the phosphonium cation is trihexyl(tetradecyl)phosphonium or P(CH 13 )3(C 14 H 29 ) + It is.

[0034] According to one embodiment of the present invention, in the composition, the ionic liquid contains dicyanamide anion (C2N3).

[0035] In this embodiment, composition (C) comprises 10 to 30 parts by weight of ionic liquid per 100 parts by weight of epoxy resin present in the composition.

[0036] In all variants and embodiments of the invention, composition (C) can be polymerized under the influence of temperature depending on the desired application and the desired properties. The method of selecting and adjusting these conditions is known to those skilled in the art.

[0037] According to another embodiment of the invention, the composition comprises an ionic liquid containing a phosphinate anion of formula (PO2R5R6), where R5 and R6 are identical or different and represent a hydrogen atom, an alkyl radical having 1 to 18 carbon atoms, an aryl radical having 6 to 20 carbon atoms, said alkyl radical and aryl radical being optionally substituted.

[0038] In this other embodiment, in the phosphinate anion, R5 and R6 are the same or different, Hydrogen atoms, an alkyl radical selected from among methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl and branched isomers thereof; an aryl radical selected from among phenyl, benzyl, The alkyl and aryl radicals are optionally substituted.

[0039] The phosphinate anion is (PO2H2) - , (PO2(CH3)2) - , (PO2(C7H 30 )2) - , (PO2Ph2) - You can choose from among:

[0040] The phosphinate anion is also known as (PO2H2) - , (PO2(CH3)2) - , (PO2(C7H 30 )2) - , (PO2Ph2) - , bis(2,4,4-trimethylpentyl)phosphinate or (PO2(CH2-CH(CH3)-CH2-C(CH3)3)2) - You can choose from among:

[0041] In this alternative embodiment, when the ionic liquid contains a phosphinate anion as described above, the composition comprises from 5 parts to 20 parts by weight of ionic liquid per 100 parts by weight of epoxy resin present in the composition.

[0042] The epoxy resin (A) present in the composition may be, for example, of the bisphenol type, such as bisphenol A, bisphenol B, bisphenol F, bisphenol S, ortho-cresol novolac, meta-cresol novolac, para-cresol novolac.

[0043] The epoxy resin (A) has a viscosity of 1 Pa·s to 150 kPa·s at a temperature of 20° C. to 25° C. The epoxy resin (A) may be, for example, a resin having a viscosity of 16.9 kPa·s (±20%) at 25° C. and 113.0 kPa·s at 20° C.

[0044] Viscosity is measured using an ARES rheometer device from TA™ instruments, Brookfield LV DV I+ from BROOKFIELD ENGINEERING LABORATORIES, INC., at a temperature between 20° C. and 25° C. The ARES rheometer uses a planar / planar geometry with 25 mm (upper geometry) and 40 mm (lower geometry) aluminum disks. The composition is applied to the geometry at an elevated temperature (60° C.) and then cooled to a temperature between 20° C. and 25° C. and viscosity measurements are taken. A "DFS" dynamic frequency sweep (strain controlled) 1 rad / s to 100 rad / s test is performed at approximately 1% deformation. Viscosity measurements are recorded at a frequency of 1 rad / s.

[0045] The composition according to the invention can be prepared by mixing components (A) and (B) as shown in the examples. In particular, this method consists of mixing the epoxy resin (A) and the ionic liquid (B) defined above, at a temperature that does not require the initiation of polymerization of (A), until a homogeneous composition is obtained.

[0046] The composition can be prepared in the presence of air in a simple reactor (made of glass) equipped with an impeller, and the temperature can be controlled by a heater plate and a silicone oil bath.

[0047] Continuous mixing is a method in which the components are continuously discharged directly into a mixing zone, resulting in a continuous flow of the mixed product at the mixer outlet. This principle ensures complete control of the point where the components meet, and thus a unique distribution quality of the mixed product. The resulting product is therefore in the form of a homogeneous mixture. Any continuous mixer known to those skilled in the art may be suitable for the preparation of the composition.

[0048] Without wishing to be bound by theory, the inventors have noted that the use of ionic liquids as curing agents in the compositions according to the invention allows crosslinking via a catalytic mechanism rather than an addition mechanism. In addition to shortening the heat treatment time, the use of ionic liquids allows a reduction in the amount of polymerization (or curing) agent required for complete crosslinking of the epoxy matrix (i.e., 20 to 50 parts per 100 parts of resin, or phr, for standard amine systems). In fact, ionic liquids allow the opening of the oxirane ring due to nucleophilic attack of the anion on the alpha carbon of this functional group, depending on the temperature.

[0049] This so-called activation reaction results in the formation of an alkoxide, a functional group reactive towards other epoxy motifs. The second so-called propagation step consists of the homopolymerization of the alkoxide motif formed on the oxirane ring.

[0050] Under suitable temperature conditions, the reaction continues until complete crosslinking of the epoxy matrix is ​​achieved (>95% conversion).

[0051] Another object of the invention is a semi-finished product, also called a towpreg, comprising: A fiber bundle (F) selected from carbon fiber, glass fiber, aramid fiber, silicon carbide fiber, and organic fiber; A composition (C) according to the present invention, The fiber bundle is impregnated with the composition, The volume content of (F) is 40% to 70%, and the volume content of (C) is 30% to 60%.

[0052] The terms "semi-finished product" and "towpreg" are interchangeable and can be used interchangeably to describe the same product.

[0053] By organic fibres is meant carbon and hydrogen based fibres, which may be natural (cellulose, silk, linen), cellulose derived (cellulose acetate, etc.) or synthetic (polyester, polyethylene, etc.).

[0054] The fiber bundles may be in the form of non-woven loose fiber sheets or aggregates, or in a woven form.

[0055] The bundle of reinforcing fibers preferably contains 1,000 to 70,000 filaments having a diameter of 3 μm to 100 μm.

[0056] The fibers (D) are preferably carbon fibers, an example of which is Torayca T720 carbon fiber from Toray Industries, Inc. (trademark).

[0057] Semi-finished products, also called towpregs, are, as the name suggests, intermediate products intended to be used, especially after hot forming, in the manufacture of composite structures, for example Type IV pressure vessels made from composite materials.

[0058] The semi-finished product or towpreg is (i) heating a composition (C) containing a resin (A) and an ionic liquid (B) at a temperature of 40°C to 60°C; (ii) continuously impregnating the moving fiber bundle (F) with composition (C); The composition can be produced by a continuous production method including the steps of:

[0059] In this way, continuous production takes place without interruption, with a continuous flow of composition and fibers (F) converging at a single location, and the final product, here a semi-finished product or towpreg, being discharged without interrupting the process.

[0060] The continuous impregnation of the fiber bundles (F) with the composition (C) is carried out at a temperature which may range from 20°C to 80°C.

[0061] The impregnation time may range from a few seconds to a few minutes, for example, from 10 seconds to 5 minutes.

[0062] After step (ii), the impregnated fibers are cooled to a temperature below 30°C.

[0063] In step (ii), the fiber bundles (E) can be impregnated with the composition (C) in several ways, including spraying, dipping or transfer, by methods known to those skilled in the art.

[0064] The semi-finished product or towpreg can be stored as is after production. The semi-finished product can also be wound, for example, on a spool.

[0065] The semi-finished product can be used for filament winding into a polymeric bladder or liner, especially a polyethylene or polyamide bladder or liner.

[0066] The bladder (or liner) may be a container made of composite materials for on-board storage of gaseous hydrogen, such as a hydrogen container, in particular a Type IV pressure vessel.

[0067] The invention also relates to the use of the composition (C) according to the invention, or a semi-finished product or a towpreg according to the invention, for the manufacture of hydrogen containers, in particular type IV pressure containers, made from the composite material, in particular for on-board storage of gaseous hydrogen for both stationary and mobile applications, such as hydrogen storage infrastructure, transportation of hydrogen for refueling, hydrogen rail cars, buses, trucks, planes, boats and other hydrogen vehicles, and hydrogen automobiles.

[0068] The present invention also relates to a method for producing a hydrogen container, in particular a type IV pressure tank, which comprises the step of molding a composition (C) according to the invention.

[0069] In a first embodiment of this process, the composition (C) is introduced unpolymerized into a mold having the desired size and shape of the resulting hydrogen container and then polymerized.

[0070] In a second embodiment of this method, the already polymerized composition (C) is brought to the desired size and shape of the hydrogen container, for example by machining.

[0071] Another object of the invention is a structure made from a composite material that includes a polymeric semi-finished product or towpreg.

[0072] The polymerization can be carried out using polymerization methods known to those skilled in the art, for example under the influence of temperature.

[0073] More specifically, the structure is a pressure vessel.

[0074] The vessel is preferably a Type IV pressure vessel for on-board storage of gaseous hydrogen.

[0075] According to one embodiment, the polymeric towpreg is wound onto a polymeric bladder or liner, particularly a polyethylene bladder or liner.

[0076] According to another embodiment, the polymeric towpreg is wound onto a polymeric bladder or liner, particularly a polyamide bladder or liner.

[0077] The vessel is preferably a Type IV pressure vessel for on-board storage of gaseous hydrogen.

[0078] For this reason, the invention also relates to a method for producing a hydrogen container, in particular a type IV pressure container, comprising the steps of shaping a semi-finished product according to the invention and subsequently polymerizing the shaped semi-finished product according to claim 9.

[0079] The composition (C) according to the invention is heat-treated quickly (for only a few hours) during the manufacture of type IV pressure composite vessels for on-board storage of gaseous hydrogen. The rapid heat-treatment of the composition is substantially due to the use of ionic liquids as curing agents.

[0080] The composition of the invention comprises an epoxy resin (A) since this type of thermosetting polymer is the most commonly used for the manufacture of pressure vessels for on-board hydrogen storage.

[0081] It is adapted to have the required properties to allow the production of a semi-finished product called a towpreg, for example by impregnating a bundle / sheet of carbon fibre, using a hot melt process. This semi-finished product or towpreg, which may be in the form of a spool, is then used to manufacture the container. The epoxy matrix is ​​applied around a bladder or liner, most often by filament winding, and is then polymerised, generally in an oven or tunnel oven. The containers thus obtained can be approved according to the criteria of the regulation currently in force (406 2010, R134). EXAMPLES

[0082] Protocol for preparing the composition according to the invention The hot melt type SR 1228 resin sold by Sicomin has a viscosity of 113 kPa·s at 20°C. Sicomin's SR 1228 resin is semi-solid and amorphous at room temperature (20°C to 25°C). Therefore, it must be heated to around 50°C in order to be used.

[0083] After the resin is introduced into a thermostatically controlled reactor, the ionic liquid Cyphos™ LI 105 (trihexyl(tetradecyl)phosphonium dicyanamide) sold by Strem Chemicals is added in an amount of 15 parts by weight (phr) (15 parts of Cyphos™ LI 105 per 100 parts of SR 1228 resin). The mixture is stirred at 60° C. for approximately 30 minutes.

[0084] After homogenization, a composition according to the invention is obtained and can be used for impregnation of reinforcing fibers. During this process, the composition is continuously sprayed onto Torayca T720 carbon fiber tows from Toray Industries, Inc. (trademark) at a maximum temperature of 60°C to 80°C.

[0085] The tow impregnated with the composition (resin + ionic liquid) can then be wound up in the form of a semi-finished product or towpreg and allowed to cool. Storage is preferably carried out in a clean, dry place, protected from light and at a temperature of up to 20° C. Under these conditions, depending on the ionic liquid used, the invention makes it possible to guarantee a semi-finished product or towpreg life of at least 2 weeks and up to more than 4 weeks.

[0086] Heat Treatment Cycle The heat treatment cycle proposed for the polymerization of the composition prepared above lasts for 5 hours, with the polymerization step lasting 0.5 hours at 100° C., followed by 1.5 hours at 120° C. and then 2 hours at 130° C.

[0087] In summary, the compositions according to the present invention can be used to prepare towpregs that can be used within 2 to 4 weeks for filament winding applications for Type IV hydrogen containers. These compositions address the issue of heat treatment time by providing polymerization times of less than 5 hours for thick composites (greater than 30 mm). In addition, these compositions can be used for both PE (polyethylene) and PA (polyamide) liners, the two main polymeric materials used in the manufacture of hydrogen containers. Finally, these compositions can be used to replace amine curing agents, which are undesirable from a health perspective.

Claims

1. Composition (C), (A) 70 parts by mass to 95 parts by mass of an epoxy resin having a viscosity of 1 Pa s to 150 kPa s at a temperature of 20°C to 25°C; (B) a curing agent dispersed in the resin in an amount of from 5 parts by weight to 30 parts by weight per 100 parts by weight of resin present in the composition, the curing agent having the formula P(R １ R ２ R ３ R ４ ) ＋ (In the formula, R １ , R ２ , R ３ and R ４ are the same or different and represent a hydrogen atom, an alkyl radical having 1 to 18 carbon atoms, or an aryl radical having 6 to 20 carbon atoms; and a curing agent, which is an ionic liquid containing a phosphonium cation of A composition comprising:

2. The phosphonium cation is PH ４ ＋ , P(CH ３ ) ４ ＋ , P(Ph) ４ ＋ , P(CH ３ ) (Ph) ３ ＋ , P(CH ２ OH) ４ ＋ , P(C ６ H １３ ) ３ (C １４ H ２９ ) ＋ 2. The composition according to claim 1, characterized in that it is selected from the group consisting of:

3. The ionic liquid is a dicyanamide anion (C ２ N ３ ) － 3. The composition according to claim 1 or 2, characterized in that it contains:

4. 4. The composition of claim 3, comprising 10 to 30 parts by weight of ionic liquid per 100 parts by weight of epoxy resin present in the composition.

5. The ionic liquid has the formula (PO ２ R ５ R ６ ) (wherein, R ５ and R ６ and (x, y, y, y) are the same or different and represent a hydrogen atom, an alkyl radical having 1 to 18 carbon atoms, or an aryl radical having 6 to 20 carbon atoms.

6. The phosphinate anion (PO ２ H ２ ) － , (PO ２ (CH ３ ) ２ ) － , (PO ２ (C ７ H ３０ ) ２ ) － , (PO ２ Ph ２ ) － , (PO ２ (CH ２ -CH(CH ３ )-CH ２ -C(CH ３ ) ３ ) ２ ) － 6. The composition according to claim 5, characterized in that it is selected from the group consisting of:

7. 6. The composition of claim 5, comprising 5 to 20 parts by weight of ionic liquid per 100 parts by weight of epoxy resin present in the composition.

8. 2. The composition of claim 1, wherein the epoxy resin (A) has a viscosity of 16.9 kPa·s (±20%) at 25°C and 113.0 kPa·s at 20°C.

9. a fiber bundle (F) selected from carbon fibers, glass fibers, aramid fibers, silicon carbide fibers, and organic fibers; The composition (C) according to claim 1; The fiber bundle is impregnated with the composition, A semi-finished product characterized in that the volume content of (F) is 40% to 70% and the volume content of (C) is 30% to 60%.

10. 10. Use of the composition (C) according to claim 1 or the semi-finished product according to claim 9 for the manufacture of a type IV pressure vessel made from the composite material for the on-board storage of gaseous hydrogen.

11. 10. A structure made from a composite material comprising the polymeric preform or towpreg of claim 9.

12. 12. A structure according to claim 11, characterized in that it is a type IV pressure vessel for on-board storage of gaseous hydrogen.

13. 10. A method for producing a Type IV pressure vessel for on-board storage of gaseous hydrogen, comprising the steps of achieving a desired shape of the unpolymerized composition of claim 1, and subsequently polymerizing the desired shaped composition of claim 1.

14. 10. A method of manufacturing a Type IV pressure vessel for on-board storage of gaseous hydrogen comprising the step of achieving a desired shape of the polymerized composition of claim 1.

15. 10. A method for manufacturing a type IV pressure vessel for on-board storage of gaseous hydrogen, comprising the steps of achieving a desired shape of the blank of claim 9 and subsequently polymerizing the shaped blank of claim 9.