Method for manufacturing hollow body by filament winding, system for manufacturing thereof and hollow body obtained

Abstract

The invention relates to a method (100) for manufacturing a hollow body, preferably an axisymmetric hollow body, comprising a layer of composite material, said process comprising the following steps: A step of providing (110) a polymeric composition; A step of impregnating (120) a fibrous material with the polymeric composition; A step of winding (130) the impregnated fibrous material around a mandrel, said winding being carried out for a winding duration; And a step of heating (150) the winded fibrous material, said heating being carried out for a heating duration to polymerize the layer of composite material; Wherein: the polymeric composition comprises a combination of a photoinitiator and a heat activated initiator; It further comprises a step of exposing (140) the polymeric composition to an UV light; And the heating duration is shorter than the winding duration.

Description

METHOD FOR MANUFACTURING HOLLOW BODY BY FILAMENT WINDING , SYSTEMFOR MANUFACTURING THEREOF AND HOLLOW BODY OBTAINED[Field of the invention]

[0001] The present invention relates to the field of filament winding and production of hollow body, such as axisymmetric hollow body, by filament winding . Manufactured hollow body can be used as high- pressure gas storage tanks .

[0002] In particular, this invention provides a new method for manufacturing a hollow body comprising a layer of composite material , a new system for manufacturing thereof and hollow body obtainable with this method .[Description of Related Art]

[0003] Filament winding technology has a wide spectrum of applications , contributing significantly to various industries thanks to its unique capabilities , particularly in the production of composite pressure vessels and pipes . This filament winding technology typically involves wrapping fibrous materials , often preimpregnated with a polymeric composition, around a mandrel to form the desired shape . This method is mainly used to create hollow cylindrical structures such as high-pressure vessels . The mechanical strength of the structure depends not only on the composition of the composite material , but also on process parameters such as winding angle , fiber tension, resin type and curing cycle ( Blachut , et al . , Composite Structures , Volume 304 , Part 1 , 15 January 2023 , 116337 , pages 1-15 ) .

[0004] The application of filament winding technology is particularly important in the production of high-pressure tanks , such as those used to store gases under high pressure . These tanks typically require materials with a high strength-to-weight ratio , and filament winding provides an efficient way to use materials such as carbon or glass fibers combined with polymeric compositions to meet these requirements . Filament winding technology is one of the emerging manufacturing practices that has revolutionized the doctrine of gas storage and transportation . Different pressure vessels have evolvedover the past decades from metal to fiber-reinforced tanks, primarily for reasons of weight reduction and high pressure. For example, Type 4 composite pressure vessels (CPVs) can reduce the weight of fuel gas tanks by 75% compared to metal tanks. Several advances have been made in filament winding's applications, addressing various process parameters, optimization techniques, and challenges in the context of high-pressure gas and cryogenic fluid storage (M. Azeem et al., Journal of Energy Storage, Volume 49, May 2022, 103468, pages 1-6) .

[0005] The document US6,074,595 discloses a method of making pressure vessels and an apparatus for manufacturing tubular pressure vessels from polymer impregnated fibrous material. The method involves two resin systems with two different initiator systems.

[0006] In particular, a significant advance in filament winding technology has been the integration of computer numerical control (CNC) systems. CNC technology has enabled greater precision in the control of key winding parameters such as fiber tension, winding angle and speed. This precision participates to ensure the structural integrity and uniformity of high-pressure vessels, directly impacting their safety and performance. In particular, this advance enables the creation of more complex shapes, crucial for high-pressure vessel applications. The incorporation of advanced technologies such as automated fiber placement and continuous fiber structural 3D printing has further broadened the scope of filament winding applications. Also, the selection of materials (such as glass, carbon or aramid fibers) and their combination with various polymeric systems are crucial in determining the strength and functionality of the final product.

[0007] The process, while efficient, still lacks a streamlined approach for the rapid production of high-pressure tanks. The complexity of the manufacturing process, combined with the need for precise control of various parameters, contributes to longer production times. Moreover, with the growing use of filament winding technology, there is an increasing emphasis on reducing its environmental impact. The manufacturing process, involving polymers and fibers, can have a considerable ecological footprint. Thus,there is a pressing need to develop more environmentally sustainable practices within this field .

[0008] Recent innovations have focused on developing more eco- friendly polymeric systems and recycling methods for composite materials . Efforts are also being made to minimize waste and energy consumption during the manufacturing process . These advancements aim to align filament winding technology with the broader goal of sustainable industrial practices .

[0009] However, there is still a need for solution to answer the need to balance manufacturing efficiency with environmental considerations .[Summery of the invention]

[0010] The following sets forth a simplified summary of selected aspects , embodiments and examples of the present invention for the purpose of providing a basic understanding of the invention . However, the summary does not constitute an extensive overview of all the aspects , embodiments and examples of the invention . The sole purpose of the summary is to present selected aspects , embodiments and examples of the invention in a concise form as an introduction to the more detailed description of the aspects , embodiments and examples of the invention that follow the summary .[Oil ] The invention aims to overcome the disadvantages of the prior art . In particular, the invention proposes a method for manufacturing a hollow body, preferably an axisymmetric hollow body, comprising a layer of composite material , said process comprising the following steps : a step of providing a polymeric composition; a step of impregnating a fibrous material with the polymeric composition; a step of winding the impregnated fibrous material around a mandrel , said winding being carried out for a winding duration; and a step of heating the winded fibrous material , said heating being carried out for a heating duration to polymerize the layer of composite material ; wherein :- the polymeric composition comprises a combination of a photoinitiator and a heat activated initiator;- it further comprises a step of exposing the polymeric composition to an UV light ; and- the heating duration is shorter than the winding duration .

[0012] The method developed by the inventors improves the production efficiency and allows easier and faster production with more environmentally sustainable practices .

[0013] According to other optional features of the method according to the invention, it can optionally include one or more of the following characteristics alone or in combination :- the step of heating the winded fibrous material is carried out at a heating temperature and the heat activated initiator has half lifetime at the heating temperature of the heating step that is lower than the winding duration,- the step of impregnation is carried out at an impregnating temperature and the impregnating temperature is selected such that the heat activated initiator has a half-life time at the impregnating temperature higher than the winding duration,- the step of heating is carried out at a heating temperature and the heat activated initiator has a half-life time at the heating temperature of at most the heating duration .- the heat activated initiator is selected among heat activated initiators having a half life time at the heating temperature that is at least 10 times shorter than its half-life time at the winding temperature .- the heat activated initiator is selected among heat activated initiators having a half-life time of less than 1 hour at a temperature of 150 ° C .- the heating step is carried out at a temperature of 100 ° C or less .- the polymeric composition has a dynamic viscosity of more than 10 mPa*s as measured at 25 ° C .- the polymeric composition has a dynamic viscosity of less than 5000 mPa*s as measured at 25 ° C . Preferably, the polymeric composition has a dynamic viscosity of more than 10 mPa*s and less than 5000 mPa*s as measured at 25 ° C .the fibrous material is selected among carbon fibers or glass fibers .- the contact of the impregnated fibrous material with the mandrel can be direct or indirect.- the step of heating is carried out while the winded fibrous material is motionless.- the step of heating is carried out while the winded fibrous material is positioned vertically, e.g. the axis of symmetry of the winded fibrous material is perpendicular to the ground.- it further comprises, after the heating step, a step of coating the layer of composite material.- the hollow body is a tube, a storage tank, a pressure vessel, a pipe, a storage tank under pressure or high pressure, utility poles, drive shaft, or wind turbine blades.- the hollow body comprise several layers, including a liner.- the polymeric composition is a thermoplastic composition.- the polymeric composition comprises a thermoplastic polymer from the family of polyamide, polyurea, polyacrylic, poly (aryl ether ketones) , polyimides, aromatic polyetherimides, polysulfides, polysulfones, polyolefins, polylactic acid, polyvinyl, polyvinyl alcohol, fluoropolymers, styrenes, cellulosics, polyester and / or polycarbonates.- the thermoplastic composition comprises a (meth) acrylic polymer .- the layer of composite material comprises from 20 % to 50 % in volume of a polymeric composition including (meth) acrylic polymers, and from 50 % to 80 % in volume of fibers.- the layer of composite material comprises at most 35 % in volume of a thermoplastic matrix comprising (meth) acrylic polymer and at least 65 % in volume of fiber.

[0014] According to another aspect, the invention can also relate to a hollow body which can be obtained from a method according to the invention. Such structure has better reinforcement and may have a longer lifetime.

[0015] According to another aspect, the invention can also relate to the use of a hollow body according to the invention gas storage,gas transportation, pressure vessel , water transportation, sewage transportation, aerospace components , or automotive components .

[0016] According to another aspect , the invention can also relate to a system for manufacturing a hollow body comprising a layer of composite material , said system comprising : an impregnation device configured to wet a fibrous material with a polymeric composition, said polymeric composition comprising a combination of a photoinitiator and a heat activated initiator, at least one UV light configured to exposing the polymeric composition to an UV light , a winding device configured to wind the fibrous material around a mandrel according to a winding duration, a heating device configured to heat the winded fibrous material to polymerize the layer of composite material according to a heating duration, the heating duration being shorter than the winding duration .

[0017] Preferably, the system comprises at most as many heating devices as winding devices .

[0018] Preferably, the heating device and the winding device are configured to operate continuously .[Brief description of drawings ]

[0019] The foregoing and other obj ects , features and advantages of the present invention will become more apparent from the following detailed description when taken in conj unction with the accompanying drawings in which :

[0020] FIG . 1 is a flowchart of a method according to an embodiment of the present invention .

[0021] Several aspects of the present invention are disclosed with reference to flow diagrams and / or block diagrams of methods , and devices according to embodiments of the invention .

[0022] On the figures , the flow diagrams and / or block diagrams show the architecture , the functionality and possible implementation of devices or systems or methods , according to several embodiments of the invention .

[0023] For this purpose , each box in the flow diagrams or block diagrams may represent a system, a device , a module which comprises several executable instructions for implementing the specified logical function ( s ) .

[0024] In some implementations , the functions associated with the box may appear in a different order than indicated in the drawings .

[0025] For example , two boxes successively shown, may be executed substantially simultaneously, or boxes may sometimes be executed in the reverse order , depending on the functionality involved .

[0026] Each box of flow diagrams or block diagrams and combinations of boxes in flow diagrams or block diagrams may be implemented by special systems that perform the specified functions or actions or perform combinations of special equipment and computer instructions .[Detailed description]

[0027] A description of example embodiments of the invention follows .

[0028] By "polymer" is meant either a copolymer or a homopolymer or a block copolymer . The term "copolymer" means a polymer grouping together several different monomer units and the term "homopolymer" means a polymer grouping identical monomer units . By "block copolymer" is meant a polymer comprising one or more uninterrupted blocks of each of the distinct polymer species , the polymer blocks being chemically different from each other and being linked together by a covalent bond . These polymer blocks are also called polymer blocks .

[0029] The expression "polymer composite" , within the meaning of the invention, denotes a multicomponent material comprising at least two immiscible components in which at least one component is a polymer, and the other component may for example be a fibrous reinforcement .

[0030] By "fibrous reinforcement" or "fibrous substrate" or "fibers" is meant , within the meaning of the invention, several fibers , unidirectional fibers or of braids , or a continuous filament mat , fabrics , felts , or nonwovens which may be under the form of bands , webs , braids , wicks or pieces .

[0031] The term "monomer" , within the meaning of the invention, can refer to a molecule which can undergo polymerization .

[0032] For the purposes of the invention, the expression "thermoplastic polymer" can refer to a polymer which is generally solid at room temperature , which may be crystalline , semicrystalline or amorphous , and which softens during an increase in temperature , in particular after passing its glass transition temperature (Tg ) and flowing at a higher temperature and / or being able to observe a clear melting at the passage of its so-called melting temperature ( Tm) (when it is semi-crystalline ) , and which becomes solid again when the temperature drops below its melting point and below its glass transition temperature . This also applies for thermoplastic polymers slightly crosslinked by the presence of multifunctional monomers or oligomers in the formulation of the "syrup" (meth) acrylate , in percentage by mass preferably less than 10% , preferably less than 5% and so preferred less than 2 % and may be at least 0 . 5 % , which can be thermoformed when heated above the softening temperature . The Tg and Tm may be determined by differential scanning calorimetry ( DSC ) according to the standards 11357-2 : 2013 and 11357-3 : 2013 respectively .

[0033] The expression "polymeric composition" can refer to a composition comprising polymer and / or polymer precursors .

[0034] The expression "thermoplastic composition" can refer to a composition comprising a thermoplastic polymer and / or a thermoplastic polymer precursor .

[0035] The expression " (meth) acrylic monomer" can refer to any type of acrylic and methacrylic monomer .

[0036] The expression " (meth) acrylic polymer" can refer to a polymer essentially comprising (meth) acrylic monomers which represent at least 50% by weight or more of the (meth ) acrylic polymer .

[0037] The term "PMMA" , within the meaning of the invention, can refer to homopolymers and copolymers of methyl methacrylate (MMA) , the weight ratio of MMA in the PMMA preferably being at least 70% by weight for the MMA copolymer .

[0038] The term "axi symmetric" within the meaning of the invention, can refer to a body, preferably a hollow body that is symmetric around a central axis .

[0039] The term "matrix" can refer to a material serving as a binder and capable of transferring forces to the fibrous reinforcement .

[0040] The "polymar matrix77may include polymers but can also include other compounds or materials .

[0041] The " (meth) acrylic polymer matrix" may refer to all types of compounds , polymers , oligomers , copolymers or block copolymers , acrylics and methacrylics . However , it would not be departing from the scope of the invention if the (meth) acrylic polymer matrix comprises up to 10% by weight , preferably less than 5% by weight of other non-acrylic monomers , chosen for example from the group : butadiene , isoprene , styrene , substituted styrene such as a- methylstyrene or tert-butylstyrene , cyclosiloxanes , vinylnaphthalenes and vinyl pyridines .

[0042] The term "initiator" , or "precursor" within the meaning of the invention, can refer to a compound which can start / initiate the polymerization of a monomer or of monomers .

[0043] The term "half lifetime" as used refers to the time needed for an initial amount of initiator to decrease its concentration or amount in half . This time is a function of the temperature .

[0044] The term "polymerization" within the meaning of the invention can refer to the process of converting a monomer or a mixture of monomers into a polymer .

[0045] The abbreviation "phr" can refer to parts by weight per hundred parts of composition . For example , 1 phr of initiator in the composition means that 1 kg of initiator is added to 100 kg of composition .

[0046] The abbreviation "ppm" can refer to parts by weight per million parts of composition . For example , 1000 ppm of a compound in the composition means that 0 . 1 kg of the compound is present in 100 kg of the composition .

[0047] The term "about" as used herein can allow for a degree of variability in a value or range , for example , within 10% , within 5% , or within 1% of a stated value or of a stated limit of a range .

[0048] The term "a" or "an" as used herein can refer to "one or more" unless explicitly stated otherwise .

[0049] As mentioned, the current process and filament winding do not ensure easier production and faster production . In addition, current processes do not ensure the balance between manufacturing efficiency and environmental considerations .

[0050] The current manufacturing processes for hollow tanks , such as pressure vessels or storage containers , often encounter significant inefficiencies due to bottlenecks in production . These bottlenecks can arise from various factors , including but not limited to , limitations in material handling , process delays , or suboptimal design and fabrication techniques . Moreover, these conventional processes typically involve substantial energy consumption and environmental impact , leading to increased operational costs and ecological concerns . There is a pressing need for an improved manufacturing process that not only addresses these inefficiencies and production bottlenecks but also promotes a more sustainable , eco-friendly approach . This invention seeks to provide a novel solution to these problems by introducing an innovative method for manufacturing hollow tanks that significantly enhances production efficiency and reduces environmental impact .

[0051] According to a first aspect , the invention relates to a method 100 for manufacturing a hollow body, preferably an axisymmetric hollow body, comprising a layer of composite material .

[0052] The hollow body, preferably axisymmetric hollow body, may correspond to a container, a vessel or a tank having an internal volume .

[0053] As illustrated in the figure 1 , a method 100 according to the invention comprise the steps of : providing 110 a polymeric composition; impregnating 120 a fibrous material with the polymeric composition; winding 130 the impregnated fibrous material on a mandrel ; exposing 140 the polymeric composition to an UV light and heating 150 the winded fibrous material .

[0054] A method 100 according to the invention can further comprise a step of cooling 160 the layer of composite material and / or a step of coating 170 the layer of composite material .

[0055] As mentioned, a method 100 according to the invention comprises a step of providing 110 a polymeric composition .

[0056] The polymeric composition comprises a combination of a photoinitiator and a heat activated initiator ;

[0057] The combination of at least two initiators , each working on at least two modalities allows a reduction in the overall duration ofthe manufacturing method and allow an improvement of the surface properties of the produced hollow body .Photoinitiator

[0058] As it comprises at least one photoinitiator, the polymeric composition according to the invention can be polymerized or crosslinked under electromagnetic radiation .

[0059] The composition according to the invention can comprise from 0 . 1 percent to 5 percent by weight , preferably from 0 . 5 percent to 3 percent by weight , even more preferentially from 1 percent to 2 percent by weight , of photoinitiator ( s ) , relative to the total weight of the polymeric composition .

[0060] The photoinitiator can be any radical photoinitiator known to those skilled in the art , in particular any radical photoinitiator known to those skilled in the art . Under the action of UV / visible radiation, the radical photoinitiator generates radicals which will be responsible for the initiation of the photopolymerization reaction and makes it possible in particular to increase the efficiency of the photopolymerization reaction . This is , of course , chosen as a function of the light source used, according to its ability to efficiently absorb the radiation selected . It will be possible , for example , to choose the appropriate radical photoinitiator from its UV / visible absorption spectrum . Advantageously, the radical photoinitiator is appropriate for working with irradiation sources emitting in the near zone of the visible region . Advantageously, the source of the UV or visible radiation can be an LED or an UV lamp .

[0061] Preferably, said at least one radical photoinitiator is chosen from the group consisting : of radical photoinitiators of type I chosen from: o the family of the acetophenones and alkoxyacetophenones , such as , for example , 2 , 2-dimethoxy-2-phenylacetophenone and 2 -diethyl- 2 -phenylacetophenone ; o the family of the hydroxyacetophenones , such as , for example , 2 , 2 -dimethyl-2-hydroxyacetophenone , 1- hydroxycyclohexyl phenyl ketone , 2 -hydroxy-4 ' - ( 2- hydroxyethoxy) -2 -methylpropiophenone and 2-hydroxy-4 ' - ( 2- hydroxypropoxy ) -2-methylpropiophenone ;o the family of the alkylaminoacetophenones, such as, for example, 2-methyl-4 ' - (methylthio) -2- morpholinopropiophenone , 2-benzyl-2- (dimethylamino) -4- morpholinobutyrophenone and 2- ( 4-methylbenzyl ) -2- ( dimethylamino ) -4-morpholinobutyrophenone ; o the family of the benzoin ethers, such as, for example, benzil, benzoin methyl ether and benzoin isopropyl ether; o the family of the phosphine oxides, such as, for example, diphenyl ( 2 , 4 , 6-trimethylbenzoyl ) phosphine oxide (TPO) , ethyl ( 2 , 4 , 6-trimethylbenzoyl ) phenylphosphine oxide (TPO- L) and bis ( 2 , 6-dimethoxybenzoyl ) -2 , 4 , 4- trimethylphenylphosphine oxide (BAPO) ; o the family of the metallocenes, such as, for example, ferrocene, bis (eta5-2, 4-cyclopentadien-l-yl ) bis (2, 6- dif luoro-3- ( IH-pyrrol-l-yl ) phenyl ) titanium and (cumene) ( cyclopentadienyl ) iron hexafluorophosphate; of radical photoinitiators of type II chosen from: o the family of the benzophenones, such as, for example, 4- phenylbenzophenone , 4- ( 4 ' -methylphenylthio ) benzophenone or 1 [ 4- [ ( 4 -benzoylphenyl ) thio] phenyl ] -2 -methyl- 2- [ ( 4- methylphenyl ) sulfonyl] -1-propanone ; o the family of the thioxanthones, such as, for example, isopropylthioxanthone (ITX) , 2 , 4-diethylthioxanthone, 2 , 4-dimethylthioxanthone, 2-chlorothioxanthone and 1- chl oro-4 -isopropyl thioxanthone ; o the family of the quinones, such as, for example, anthraquinones, including 2-ethylanthraquinone, and camphorquinones ; o the family of the benzoylformate esters, such as, for example, methyl benzoylformate; o the family of the dibenzylidene ketones, such as, for example, the p-dimethylamino ketone; o the family of the coumarins, such as, for example, 5- methoxy- and 7-methoxycoumarin, 7-diethylaminocoumarin and N-phenylglycine coumarin; of radical photoinitiators of the family of the dyes, such as, for example, triazines, fluorones, cyanines, safranins,4,5, 6, 7-tetrachloro-3 ' , 6 ' -dihydroxy-2 ' , 4 ' , 5 ' , 7 ' -tetraiodo-3H- spiro [isobenzofuran-1, 9 ' -xanthen] -3-one, pyryliums and thiopyryliums , thiazines, flavins, pyronines, oxazines or rhodamines ;- and of mixtures thereof.

[0062] More preferably, said at least one radical photoinitiator is chosen from the group consisting: of radical photoinitiators of type I chosen from: o the family of the acetophenones and alkoxyacetophenones, such as, for example, 2 , 2-dimethoxy-2-phenylacetophenone and 2 -diethyl- 2 -phenylacetophenone ; o the family of the hydroxyacetophenones, such as, for example, 2, 2-dimethyl-2-hydroxyacetophenone, 1- hydroxycyclohexyl phenyl ketone, 2 -hydroxy-4 '-( 2- hydroxyethoxy) -2-methylpropiophenone and 2-hydroxy-4 ' - ( 2- hydroxypropoxy ) -2-methylpropiophenone ; o the family of the alkylaminoacetophenones, such as, for example, 2-methyl-4 ' - (methylthio) -2- morpholinopropiophenone , 2-benzyl-2- (dimethylamino) -4- morpholinobutyrophenone and 2- ( 4-methylbenzyl ) -2- ( dimethylamino ) -4-morpholinobutyrophenone ; o the family of the benzoin ethers, such as, for example, benzil, benzoin methyl ether and benzoin isopropyl ether; o the family of the phosphine oxides, such as, for example, diphenyl ( 2 , 4 , 6-trimethylbenzoyl ) phosphine oxide (TPO) , ethyl ( 2 , 4 , 6-trimethylbenzoyl ) phenylphosphine oxide (TPO- L) and bis ( 2 , 6-dimethoxybenzoyl ) -2 , 4 , 4- trimethylphenylphosphine oxide (BAPO) ; o the family of the metallocenes, such as, for example, ferrocene, bis (eta5-2, 4-cyclopentadien-l-yl ) bis (2, 6- dif luoro-3- ( IH-pyrrol-l-yl ) phenyl ) titanium and (cumene) ( cyclopentadienyl ) iron hexafluorophosphate; of radical photoinitiators of type 11 chosen from: o the family of the benzophenones, such as, for example, 4- phenylbenzophenone , 4- ( 4 ' -methylphenylthio ) benzophenone or 1- [ 4- [ ( 4 -benzoylphenyl ) thio ] phenyl ] -2 -methyl -2- [ ( 4- methylphenyl ) sulfonyl] -1-propanone ;o the family of the thioxanthones, such as, for example, isopropylthioxanthone (ITX) , 2 , 4-diethylthioxanthone, 2 , 4-dimethylthioxanthone , 2-chlorothioxanthone and 1- chl oro-4 -isopropyl thioxanthone ; o the family of the benzoylformate esters, such as, for example, methyl benzoylformate; o the family of the dibenzylidene ketones, such as, for example, the p-dimethylamino ketone; o the family of the coumarins, such as, for example, 5- methoxy- and 7-methoxycoumarin, 7-diethylaminocoumarin and N-phenylglycine coumarin; of radical photoinitiators of the family of the dyes, such as, for example, triazines, fluorones, cyanines, safranins, 4,5, 6, 7-tetrachloro-3 ' , 6 ' -dihydroxy-2 ' , 4 ' , 5 ' , 7 ' -tetraiodo-3H- spiro [isobenzofuran-1, 9 ' -xanthen] -3-one, pyryliums and thiopyryliums , thiazines, flavins, pyronines, oxazines or rhodamines ; and of mixtures thereof.

[0063] More preferably, the radical photoinitiator is chosen from the following radical photoinitiators :- the family of the phosphine oxides, such as, for example, diphenyl ( 2 , 4 , 6-trimethylbenzoyl ) phosphine oxide (TPO) , ethyl ( 2 , 4 , 6-trimethylbenzoyl ) phenylphosphine oxide (TPO-L) and bis ( 2 , 6-dimethoxybenzoyl ) -2 , 4 , 4-trimethylphenylphosphine oxide (BAPO) ; the family of the thioxanthones, such as, for example, isopropylthioxanthone (ITX) , 2 , 4-diethylthioxanthone, 2,4- dimethylthioxanthone, 2-chlorothioxanthone and l-chloro-4- i s opr opyl thioxanthone; the radical photoinitiator being even more preferentially chosen from diphenyl- ( 2 , 4 , 6-trimethylbenzoyl ) phosphine oxide (TPO) , ethyl- ( 2 , 4 , 6-trimethylbenzoyl ) phenylphosphine oxide (TPO-L) and bis- (2, 6- dimethoxybenzoyl ) -2 , 4 , 4-trimethylphenylphosphine oxide (BAPO) .

[0064] For example, when the source of the UV or visible radiation is an LED or UV lamps, the radical photoinitiator can be chosen from 2 , 4 , 6-trimethylbenzoyldiphenylphosphine or TPO available, forexample, from Lambson under the commercial reference Speedcure (R) TPO (CAS: 75980-60-8) , ethyl (2,4,6- trimethylbenzoyl ) phenylphosphinate or TPO-L available, for example, from Lambson under the commercial reference Speedcure (R) TPO-L (CAS: 84434-11-7) , phenylbis ( 2 , 4 , 6-trimethylbenzoyl ) phosphine oxide or BAPO (CAS: 162881-26-7) available, for example, from BASF under the commercial reference Irgacure (R) 819, 2-benzyl-2-dimethylamino-l- ( 4 -morpholinophenyl ) -1-butanone (CAS: 119313-12-1) available, for example, from BASF under the commercial reference Irgacure (R) 369, 2-methyl-l [4- (methyl thio ) phenyl ] -2- ( 4-morpholinyl ) -1 -propanone (CAS: 71868-10-5) available, for example, from BASF under the commercial reference Irgacure (R) 907, 1-hydroxycyclohexyl phenyl ketone (CAS: 947-19-3) available, for example, from BASF under the commercial reference Irgacure (R) 184, 2-isopropylthioxanthone or ITX (CAS: 5495-84-1) available, for example, under the reference Speedcure (R) 2-ITX, or mixtures thereof.Heat activated initiator

[0065] The polymeric composition can comprise a heat activated precursor or initiator which can start the polymerization of monomers in the polymeric composition when exposed to a specific temperature range. The heat activated is preferably a radical initiator activated by heat.

[0066] In a first preferred embodiment, the heat activated initiator is selected among heat activated initiators having a half-life time at the heating temperature that is at least 10 times shorter than its half-life time at the winding temperature.

[0067] In a second preferred embodiment, the heat activated initiator is selected among heat activated initiators having a half-life time at the heating temperature that is at least 20 times shorter than its half-life time at the winding temperature,

[0068] In a third preferred embodiment, the heat activated initiator is selected among heat activated initiators having a half-life time at the heating temperature that is at least 40 times shorter than its half-life time at the winding temperature,

[0069] In a fourth preferred embodiment, the heat activated initiator is selected among heat activated initiators having a half-life timeat the heating temperature that is at least 80 times shorter than its half-life time at the winding temperature.

[0070] The heat activated initiator can be selected among heat activated initiators having a half-life time of less than 1 hour at a temperature of 150°C. In a first preferred embodiment, the heat activated initiator is selected among heat activated initiators having a half-life time of less than 1 hour at a temperature of 125°C. In a second preferred embodiment, the heat activated initiator is selected among heat activated initiators having a halflife time of less than 1 hour at a temperature of 100°C. In a third preferred embodiment, the heat activated initiator is selected among heat activated initiators having a half-life time of less than 1 hour at a temperature of 95 °C.

[0071] The heat activated initiators can be chosen from a peroxy group comprising compound or an azo group comprising compounds and preferably from a peroxy group comprising compound.

[0072] Preferably, the peroxy group comprising compound comprises from 2 to 30 carbon atoms.

[0073] Preferably, the peroxy group comprising compound is chosen from diacyl peroxides, peroxy esters, peroxydicarbonates, dialkyl peroxides, peroxyacetals, hydroperoxide or peroxyketale

[0074] The heat activated initiators is chosen from diisobutyryl peroxide, cumyl peroxyneodecanoate, di ( 3-methoxybutyl ) peroxydicarbonate , 1, 1, 3, 3-Tetramethylbutyl peroxyneodecanoate, cumyl peroxyneoheptanoate, di-n-propyl peroxydicarbonate, tert-amyl peroxyneodecanoate, , di-sec-butyl peroxydicarbonate, diisopropyl peroxydicarbonate, di ( 4-tert-butylcyclohexyl ) peroxydicarbonate, di- (2-ethylhexyl) -peroxydicarbonate, tert-amyl peroxyneodecanoate, tert-butyl peroxyneodecanoate, di-n-butyl peroxydicarbonate, dicetyl peroxydicarbonate, dimyristyl peroxydicarbonate, 1, 1,3,3- tetramethylbutylperoxypivalate, tertbutyl peroxyneoheptanoate, tert-amyl peroxypivalate, tert-butyl peroxypivalate, di- (3,5,5- trimethylhexanoyl ) -peroxide, dilauroyl peroxide, didecanoyl peroxide, 2, 5-dimethyl-2 , 5-di (2- ethylhexanoylperoxy) -hexane, 1, 1 , 3, 3-tetramethylbutyl peroxy- 2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, dibenzoyl peroxide, tert-butyl peroxy-2- ethylhexanoate, tert-butylperoxydiethylacetate, tert-butyl peroxyisobutyrate, 1, 1-di- (tertbutylperoxy) -3,3,5- trimethylcyclohexane, 1, 1-di (tertamylperoxy) cyclohexane, 1, 1-di- (tert-butylperoxy) -cyclohexane, tert-amyl peroxy-2- ethylhexylcarbonate, , tert-amyl peroxyacetate, tert-butyl peroxy- 3, 5, 5-trimethylhexanoate, 2, 2-di- (tert- butylperoxy) -butane, tert- butyl peroxyisopropylcarbonate, tertbutyl peroxy-2- ethylhexylcarbonate, tert-amyl peroxybenzoate, tert-butyl peroxyacetate, butyl 4 , 4-di (tert-butylperoxy) valerate, tert-butyl peroxybenzoate, di-tert-amylperoxide, dicumyl peroxide, di- (2- tert-butyl-peroxyisopropyl ) -benzene, 2, 5- dimethyl-2 , 5-di- (tert- butylperoxy) -hexane, tert-butylcumyl peroxide, 2 , 5-dimethyl-2 , 5- di (tert-butylperoxy) hexyne-3, di- tert-butyl peroxide, 3, 6, 9- triethyl-3, 6, 9-trimethyl-l, 4, 7- triperoxonane, 2,2' -azobis- isobutyronitrile (AIBN) , 2, 2 ' - azodi- ( 2-methylbutyronitrile ) , azobisisobutyramide, 2,2' -azobis (2, 4-dimethylvaleronitrile ) , 1,1'- Azodi (hexahydrobenzonitrile) , or 4, 4' -azobis ( 4-cyanopentanoic ) .

[0075] Preferably the heat activated initiators is chosen from cumyl peroxyneodecanoate, di ( 3-methoxybutyl ) peroxydicarbonate, 1, 1,3,3- tetramethylbutyl peroxyneodecanoate, cumyl peroxyneoheptanoate, di-n-propyl peroxydicarbonate, tert-amyl peroxyneodecanoate, di- sec-butyl peroxydicarbonate, diisopropyl peroxydicarbonate, di (4- tert-butylcyclohexyl ) peroxydicarbonate, di- ( 2-ethylhexyl ) - peroxydicarbonate, tert-amyl peroxyneodecanoate, tert-butyl peroxyneodecanoate, di-n-butyl peroxydicarbonate, dicetyl peroxydicarbonate, dimyristyl peroxydicarbonate, 1, 1,3,3- tetramethylbutylperoxypivalate, tertbutyl peroxyneoheptanoate, tert-amyl peroxypivalate, tert-butyl peroxypivalate, di- (3,5,5- trimethylhexanoyl ) -peroxide, dilauroyl peroxide, didecanoyl peroxide, 2, 5-dimethyl-2 , 5-di (2- ethylhexanoylperoxy) -hexane or 1,1,3, 3-tetramethylbutyl peroxy-2- ethylhexanoate .

[0076] The polymeric composition may comprise between 0.1 phr and 5 phr of a heat activated initiators to induce the polymerization of monomers, preferably the polymerization of the (meth) acrylic monomer and (meth) acrylic comonomer.The polymeric composition

[0077] The polymeric composition can have a dynamic viscosity of more than 10 mPa*s, preferably more than 25 mPa*s, more preferably more than 50 mPa*s, even more preferably more than 100 mPa*s .

[0078] The polymeric composition can have a dynamic viscosity of less than 10 000 mPa*s, preferably less than 7000 mPa*s, more preferably less than 5000 mPa*s, even more preferably less than 2000 mPa*s.

[0079] Preferably dynamic viscosity of the polymeric composition is in a range from 10 mPa*s to 10000 mPa*s, preferably from 20 mPa*s to 7000 mPa*s and advantageously from 20 mPa*s to 5000 mPa*s and more advantageously from 20 mPa*s to 2000 mPa*s and even more advantageously between 20 mPa -s and 1000 mPa*s. The viscosity of the polymeric composition can be easily measured with a Rheometer or viscosimeter. The dynamic viscosity is measured at 25°C. If the polymeric composition has a Newtonian behaviour, meaning no shear thinning, the dynamic viscosity is independent of the shearing in a rheometer or the speed of the mobile in a viscometer. If the polymeric composition has a non-Newtonian behaviour, meaning shear thinning, the dynamic viscosity is measured at a shear rate of Is-1at 25°C.

[0080] The polymeric composition can be a thermoplastic composition or a thermoset composition. Advantageously, the polymeric composition is a thermoplastic composition.

[0081] The polymeric composition, preferably the thermoplastic composition may comprise at least 50 % in weight of monomers of a polymer preferably of a thermoplastic polymer. The thermoplastic composition may comprise at most 90 % in weight of monomers of the thermoplastic polymer. The polymeric matrix may comprise a (meth) acrylic polymers. The composition may comprise a polymer and a monomer. Preferably, the thermoplastic composition is a mixture of monomers and polymers .

[0082] The thermoplastic composition can comprise a thermoplastic polymer from the family of polyamide, polyurea, polyacrylic, poly(aryl ether ketones) , polyimides, aromatic polyetherimides, polysulfides, polysulfones, polyolefins, polylactic acid, polyvinyl, polyvinyl alcohol, fluoropolymers, styrenes, cellulosics, polyester and / or polycarbonates.

[0083] Preferably the monomer of the thermoplastic composition is selected from alkyl acrylic monomers , alkyl methacrylic monomers , hydroxyalkyl acrylic monomers and hydroxyalkyl methacrylic monomers , and mixtures thereof .

[0084] Preferably the polymer of the thermoplastic composition is selected from all types of compounds , polymers , oligomers , copolymers or block copolymers , acrylics and methacrylics . However, it would not be departing from the scope of the invention if the (meth) acrylic polymer matrix comprises up to 10% by weight , preferably less than 5% by weight of other non-acrylic monomers , chosen for example from the group : butadiene , isoprene , styrene , substituted styrene such as o-methylstyrene or tert-butylstyrene , cyclosiloxanes , vinylnaphthalenes and vinyl pyridines .

[0085] The thermoplastic composition according to the invention may comprise between 10wt% and 50wt% of a (meth) acrylic polymer and between 50wt% and 90wt% of a (meth) acrylic monomer . Preferably the thermoplastic composition comprises between 10wt% and 40wt% of a (meth) acrylic polymer and between 60wt% and 90wt% of a (meth) acrylic monomer; and more preferably between 10wt% and 30wt% of a (meth) acrylic polymer and between 70wt% and 90wt% of a (meth) acrylic monomer .

[0086] As regards thermoplastic composition of the invention, it comprises a (meth) acrylic monomer and a (meth) acrylic polymer . Once polymerized the (meth) acrylic monomer is transformed to a (meth) acrylic polymer comprising the monomeric units of (meth ) acrylic monomer and other possible monomers .

[0087] As regards the (meth ) acrylic polymer, mention may be made of polyalkyl methacrylates or polyalkyl acrylates . According to a preferred embodiment , the (meth) acrylic polymer is polymethyl methacrylate ( PMMA) .

[0088] According to one embodiment , the methyl methacrylate (MMA) homo- or copolymer comprises at least 70% , preferably at least 80% , advantageously at least 90% and more advantageously at least 95% by weight of methyl methacrylate .

[0089] According to another embodiment , the PMMA is a mixture of at least one homopolymer and at least one copolymer of MMA, or a mixture of at least two homopolymers or two copolymers of MMA with adifferent average molecular weight, or a mixture of at least two copolymers of MMA with a different monomer composition.

[0090] The copolymer of methyl methacrylate (MMA) comprises from 70% to 99.9% by weight of methyl methacrylate and from 0.1% to 30% by weight of at least one monomer containing at least one ethylenic unsaturation that can copolymerize with methyl methacrylate.

[0091] These monomers are well known, and mention may be made especially of acrylic and methacrylic acids and alkyl (meth) acrylates in which the alkyl group contains from 1 to 12 carbon atoms. As examples, mention may be made of methyl acrylate and ethyl, butyl or 2-ethylhexyl (meth) acrylate. Preferably, the comonomer is an alkyl acrylate in which the alkyl group contains from 1 to 4 carbon atoms .

[0092] According to a first preferred embodiment, the copolymer of methyl methacrylate (MMA) comprises from 80% to 99.9%, advantageously from 90% to 99.9% and more advantageously from 90% to 99.9% by weight of methyl methacrylate and from 0.1% to 20%, advantageously from 0.1% to 10% and more advantageously from 0.1% to 10% by weight of at least one monomer containing at least one ethylenic unsaturation that can copolymerize with methyl methacrylate. Preferably, the comonomer is chosen from methyl acrylate and ethyl acrylate, and mixtures thereof.

[0093] The weight-average molecular mass of the (meth) acrylic polymer should be high, which means greater than 50 000 g / mol and preferably greater than 100 000 g / mol.

[0094] The weight-average molecular mass can be measured by size exclusion chromatography (SEC) .

[0095] The (meth) acrylic polymer is fully soluble in the (meth) acrylic monomer or in the mixture of (meth) acrylic monomers. It enables the viscosity of the (meth) acrylic monomer or the mixture of (meth) acrylic monomers to be increased. The solution obtained is a liquid composition generally called a "syrup" or "liquid (meth) acrylic syrup" or "prepolymer".

[0096] Advantageously, the liquid (meth) acrylic composition or syrup contains no additional voluntarily added solvent.

[0097] As regards the (meth) acrylic monomer, the monomer is chosen from alkyl acrylic monomers, alkyl methacrylic monomers,hydroxyalkyl acrylic monomers and hydroxyalkyl methacrylic monomers, and mixtures thereof.

[0098] Preferably, the (meth) acrylic monomer is chosen from hydroxyalkyl acrylic monomers, hydroxyalkyl methacrylic monomers, alkyl acrylic monomers, alkyl methacrylic monomers and mixtures thereof, the alkyl group containing from 1 to 22 linear, branched or cyclic carbons; the alkyl group preferably containing from 1 to 12 linear, branched or cyclic carbons.

[0099] More preferably, the (meth) acrylic monomer is chosen from alkyl acrylic monomers or alkyl methacrylic monomers and mixtures thereof, the alkyl group containing from 1 to 22 linear, branched or cyclic carbons; the alkyl group preferably containing from 1 to 12 linear, branched or cyclic carbons.

[0100] Advantageously, the (meth) acrylic monomer is chosen from methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid, n-butyl acrylate, isobutyl acrylate, n-butyl methacrylate, isobutyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, hydroxyethyl acrylate and hydroxyethyl methacrylate, and mixtures thereof.

[0101] More advantageously, the (meth) acrylic monomer is chosen from methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid, n-butyl acrylate, isobutyl acrylate, n-butyl methacrylate, isobutyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, and mixtures thereof.

[0102] ccording to a preferred embodiment, at least 50% by weight and preferably at least 60% by weight of the (meth) acrylic monomer is methyl methacrylate.

[0103] According to a first more preferred embodiment, at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, advantageously at least 80% by weight and even more advantageously 90% by weight of the monomer is a mixture of methyl methacrylate with optionally at least one other monomer. For example, the at least one other monomer can be a multifunctional (meth) acrylic monomer.

[0104] Preferably the multifunctional (meth) acrylic monomer is chosen from a compound comprising at least two (meth) acrylic functions. The (meth) acrylic monomer can also be chosen from a mixture of at least two compounds each respectively comprising at least two (meth) acrylic functions.

[0105] The multifunctional (meth) acrylic monomer can be chosen from 1,3- butylene glycol dimethacrylate; 1 , 4-butanediol dimethacrylate; 1,6 hexanediol diacrylate; 1, 6 hexanediol dimethacrylate; diethylene glycol dimethacrylate; dipropylene glycol diacrylate; ethoxylated (10) bisphenol a diacrylate; ethoxylated (2) bisphenol a dimethacrylate; ethoxylated (3) bisphenol a diacrylate; ethoxylated (3) bisphenol a dimethacrylate; ethoxylated (4) bisphenol a diacrylate; ethoxylated (4) bisphenol a dimethacrylate; ethoxylated bisphenol a dimethacrylate; ethoxylated (10) bisphenol dimethacrylate; ethylene glycol dimethacrylate; polyethylene glycol (200) diacrylate; polyethylene glycol (400) diacrylate; polyethylene glycol (400) dimethacrylate; polyethylene glycol (400) dimethacrylate; polyethylene glycol (600) diacrylate; polyethylene glycol (600) dimethacrylate; polyethylene glycol 400 diacrylate; propoxylated (2) neopentyl glycol diacrylate; tetraethylene glycol diacrylate; tetraethylene glycol dimethacrylate; tricyclodecane dimethanol diacrylate; tricyclodecanedimethanol dimethacrylate; triethylene glycol diacrylate; triethylene glycol dimethacrylate; tripropylene glycol diacrylate; ethoxylated (15) trimethylolpropane triacrylate; ethoxylated (3) trimethylolpropane triacrylate; ethoxylated (6) trimethylolpropane triacrylate; ethoxylated (9) trimethylolpropane triacrylate; ethoxylated 5 pentaerythritol triacrylate; ethoxylated (20) trimethylolpropane triacrylate; propoxylated (3) glyceryl triacrylate; trimethylolpropane triacrylate; propoxylated (5.5) glyceryl triacrylate; pentaerythritol triacrylate; propoxylated (3) glyceryl triacrylate; propoxylated (3) trimethylolpropane triacrylate; trimethylolpropane triacrylate; trimethylolpropane trimethacrylate; tris (2-hydroxy ethyl) isocyanurate triacrylate; di-trimethylolpropane tetraacrylate; dipentaerythritol pentaacrylate; ethoxylated (4) pentaerythritol tetraacrylate; pentaerythritol tetraacrylate; dipentaerythritol hexaacrylate; 1,10decanediol diacrylate; 1,3-butylene glycol diacrylate; 1 , 4- butanediol diacrylate; 1 , 9-nonanediol diacrylate; 2- (2- Vinyloxyethoxy) ethyl acrylate; 2-butyl-2-ethyl-l , 3- propanediol diacrylate; 2-methyl-l , 3-propanediol diacrylate; 2- methyl-1 , 3- propanediyl ethoxy acrylate; 3 methyl 1 , 5-pentanediol diacrylate; alkoxylated cyclohexane dimethanol diacrylate; alkoxylated hexanediol diacrylate; cyclohexane dimethanol diacrylate; ethoxylated cyclohexane dimethanol diacrylate; diethyleneglycol diacrylate; dioxane glycol diacrylate; ethoxylated dipentaerythritol hexaacrylate; ethoxylated glycerol triacrylate; ethoxylated neopentyl glycol diacrylate; hydroxypivalyl hydroxypivalate diacrylate; neopentyl glycol diacrylate; poly (tetramethylene glycol) diacrylate; polypropylene glycol 400 diacrylate; polypropylene glycol 700 diacrylate; propoxylated (6) ethoxylated bisphenol A diacrylate; propoxylated ethylene glycol diacrylate; propoxylated (5) pentaerythritol tetraacrylate; and propoxylated trimethylol propane triacrylate.

[0106] Preferably the multifunctional (meth) acrylic monomer is chosen from ethylene glycol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, 1 , 4-butanediol dimethacrylate, 1 , 4-butanediol diacrylate, 1,3-butylene glucol diacrylate, 1,3- butylene glycol dimethacrylate, triethylene glycol dimethacrylate, tricyclodecanedimethanol dimethacrylate and triethylene glycol diacrylate or mixtures thereof.

[0107] The multifunctional (meth) acrylic monomer can be present in (meth) acrylic composition between 0.01 and 10 phr by weight, preferably is present between 0.1 and 9.5phr for 100 parts of a liquid (meth) acrylic syrup, more preferably between 0.1 and 9phr, even more preferably between 0.1 and 8.5phr and advantageously between 0.1 and 8phr.

[0108] In a first more preferred embodiment, the multifunctional (meth) acrylic monomer is present in (meth) acrylic composition between 0.01 and 9 phr and is chosen from a compound comprising two (meth) acrylic functions.

[0109] In a second more preferred embodiment, the multifunctional (meth) acrylic monomer is present in (meth) acrylic compositionbetween 0 . 01 and 9 phr and is chosen from a mixture of compounds comprising two (meth) acrylic functions .

[0110] In a third more preferred embodiment , the multifunctional (meth) acrylic monomer is present in (meth) acrylic composition between 0 . 01 and 9phr and is chosen from a mixture of compounds comprising at least two (meth) acrylic functions .

[0111] In a fourth more preferred embodiment , the multifunctional (meth) acrylic monomer is present in (meth) acrylic composition between 0 . 01 and 9phr and is chosen from a mixture of compounds comprising at least two (meth) acrylic functions . At least one compound of the mixture comprises only two (meth ) acrylic functions and presents at least 50wt% of the mixture of (meth) acrylic monomer, preferably at least 60wt% . The other compound of the mixture comprises more than two (meth) acrylic functions .

[0112] Preferably, the polymer formed by the polymeric composition used has a glass transition temperature (Tg ) of between 50 ° C and 160 ° C , preferably between 70 ° C and 140 ° C, and even more preferably 90 ° C and 120 ° C . This aspect gives it an advantage over other polymers such as polyamines . Indeed, polyamines generally have very high melting points , namely from 200 ° C and higher , which does not facilitate the process . Glass transition temperatures or melting points can be measured by methods well known to those s killed in the art . Preferably, these temperatures are measured by Differential Scanning calorimetry according to the conditions specified in standards ISO 11357-2 / 2013 for Tg and ISO 11357 -3 / 2011 for Tm.

[0113] As mentioned, a method 100 according to the invention comprises a step of impregnating 120 a fibrous material with the polymeric composition, preferably with the thermoplastic composition .

[0114] The impregnation is preferably implemented by an impregnation device such as a bath device , a roller impregnation device , a spray impregnation device .

[0115] The impregnation process can involve soaking or coating fibers with a polymer composition to ensure they are fully wet and / or encapsulated . The step of impregnation allows fibers to be impregnated with the polymeric composition .

[0116] The step of impregnating fibers (i.e. fibrous material) may comprise the passage of fibers through a polymeric composition. For example, the fibers are guided through a bath or an injection chamber comprising the thermoplastic composition.

[0117] Preferably, the impregnating step is conducted such the layer of composite material comprises from 20 % to 50 % in volume of a polymeric composition, and from 50 % to 80 % in volume of fibers. For example, the measurement of the glass fiber level can be determined according to ISO 1172:1999 and the measurement of the carbon fiber level can be determined according to ISO 14127:2008.FIBROUS MATERIAL

[0118] The fibrous material according to the invention may have biologic, mineral or synthetic origins.

[0119] As biologic material one can mention plant fibers, wood fibers, or animal fibers. Biologic fibers are, for example, sisal, jute, hemp, flax, cotton, coconut fibers, and banana fibers. Animal fibers are, for example, wool or hair.

[0120] Synthetic materials can include polymeric fibers chosen from fibers of thermosetting polymers, of thermoplastic polymers, of polyamide (aliphatic or aromatic) , polyester, polyvinyl alcohol, polyolefins, polyurethanes, polyvinyl chloride, polyethylene, unsaturated polyesters, epoxy resins and vinyl esters, and / or carbon fibers or mixtures thereof.

[0121] The mineral fibers may be chosen from glass fibers, especially of E, R or S2 type, boron fibers, basalt fibers or silica fibers.

[0122] Preferably, the fibers are mineral fibers. More preferably the fibers are glass fibers or carbon fibers.

[0123] The fibers can have a diameter between 0.005 pm and 100 pm, preferably between 1 pm and 50 pm, more preferably between 5 pm and 30 pm and advantageously between 10 pm and 25 pm.

[0124] Preferably, the fibers of the present invention are chosen from continuous fibers (meaning that the aspect ratio does not necessarily apply as for long fibers) for the one-dimensional form, or for long or continuous fibers for the two-dimensional or three- dimensional form of the fibrous reinforcement.

[0125] As mentioned, a method 100 according to the invention comprises a step of winding 130 the impregnated fibrous material around a mandrel .

[0126] The mandrel can be considered as a core mold . This mandrel can represent the internal shape of the hollow body . It generally directly mirrors the internal shape of the hollow body . Its shape can range from simple cylindrical forms to more complex geometric shapes , depending on the application .

[0127] Common materials for the mandrel include steel , aluminium, and composite materials themselves . The choice of material will depend on the size of the hollow body, the application, and the required precision . A release agent can be applied to the mandrel to prevent the composite layer from sticking to it , facilitating easy removal of the finished hollow body . Also , the mandrel can be recovered by a liner before being recovered by the composite layer .

[0128] The winding is generally conducted using automated systems comprising multi-axis control ( e . g . ranging from 3 to 6 axis ) allowing for complex winding patterns necessary for different tank geometries . The systems comprise usually computer numerical control over winding paths , angles , and tension . Several parameters can have an influence on the quality of the produced hollow body .

[0129] The orientation of the fiber when winded can significantly influence the mechanical properties of a hollow body . Thus , the winding angle can be optimized based on the intended load conditions of the hollow body produced . The winding angle can typically be selected from 10 ° to 90 ° relative to the longitudinal axis of the hollow body . Furthermore , the winding can comprise hoop, helical , and polar winding .

[0130] The tension applied to the fibers during winding can affect the compaction and overall quality of the laminate . The optimal tension is highly dependent on the type of fiber and the thickness of the filaments . It ' s generally adj usted to ensure proper alignment and compaction without damaging the fibers .

[0131] The speed of the winding process and the degree of automation can impact production efficiency and consistency . The winding speed can range from a few meters per minute to tens of meters per minute , depending on the equipment and the complexity of the part . In thecontext of the invention, the winding is carried out for a winding duration . For example , the filament winding speed is strictly less than 1 m / sec . However, when considering axisymmetric hollow body, the filament winding speed can be higher than 1 m / sec, preferably higher than 2 m / sec, for example higher than 3 m / sec . When the hollow body is not axisymmetric, the filament winding may be lower with for example speed of at least 0 . 1 m / sec, preferably at least 0 . 3 m / sec .

[0132] The winding step can be conducted at a winding temperature . A winding temperature may be a room temperature such as 20 ° C, or any temperature adapted to the polymeric composition used . Preferably, the winding step is conducted at room temperature .

[0133] Preferably, the winding step is conducted at a winding temperature for which the half-life time of the heat activated initiator is higher than 10 hours .

[0134] As mentioned, a method 100 according to the invention comprises a step of exposing 140 the polymeric composition to an UV light . For example , the wavelength of the UV light is from 300 to 475 nm, preferably from 325 to 450 nm, more preferably from 350 to 425 nm .

[0135] Hence it will induce a first step of polymerisation of the compounds of the polymeric composition .

[0136] The step of exposing 140 the polymeric composition to an UV light will generally involve the use of UV lamps .

[0137] Exposing of the polymeric composition to the UV light can be done before or after the first contact of the impregnated fibrous material with the mandrel . The UV light is preferably maintained over the entire duration of the winding step . The duration will depend on the power of the UV light and its wavelength . For example , the duration of the UV light exposition can be of at least 1 second .

[0138] The step of exposing the polymeric composition to an UV light allow activating the photoinitiator preferably in order to polymerize the polymeric composition .

[0139] As mentioned, a method 100 according to the invention comprises a step of heating 150 the winded fibrous material .

[0140] Preferably the step of heating is implemented by a heating device such as a mold, an enclosure, a microwave source, an IR source (NIR / MIR) , an air blower, and / or an induction source. The step of heating may comprise heating by convection, by conduction, by IR (infrared) (comprising NIR and MIR (near and mid infrared) ) , by microwave, by UV (ultraviolet) and / or by induction.

[0141] The step of heating allows an activation of the heat activated initiator can be preceded by an acceleration of the polymerization of the polymeric composition; Preferably of the thermoplastic composition which has impregnated fibers.

[0142] The step of heating 150 is carried out at a heating temperature and the heat activated initiator has a half-life time at the heating temperature of at most the heating duration.

[0143] The step of heating can be carried out at a heating temperature of 100°C or less, preferably about 90 °C and more preferably about 80 °C. According to an embodiment, the heating duration is function of the winding duration.

[0144] The step of heating may be carried out while the winded fibrous material is motionless. Preferably, the step of heating is carried out while the winded fibrous material is positioned vertically, e.g. the axis of symmetry of the winded fibrous material is perpendicular to the ground.

[0145] According to an embodiment of the step of heating 150, the polymerization may take place at a temperature typically below 140°C, preferably below 130°C and even more preferably below 125°C.

[0146] According to an embodiment of the step of heating, the polymerization may take place at a temperature of at least 40 °C, preferably at least 50 °C and more preferably at least 60 °C.

[0147] Preferably the polymerization may take place at temperature between 40°C and 140°C, preferably between 50°C and 130°C, even more preferably between 60°C and 125°C.

[0148] Advantageously, the step of heating may be implemented continuously or not, preferably it is implemented continuously.

[0149] The heating step and the polymerization allow to pass from a polymeric composition which has impregnated the fibers.

[0150] After the composite material is wound around the mandrel and cured, the mandrel must be removed from the finished hollow body.This can be achieved by shrinking (for metal mandrels) , mechanically extracting, or, in some cases, the mandrel is designed to collapse or segment into parts for easy removal .

[0151] The method according to the invention may comprise a step of cooling 160 the layer of composite material. In a particular embodiment, the step of cooling may be implemented by a cooling device such as a convection cooling system or a system comprising heat exchanger (s) . In addition, the step of cooling may be implemented at a given cooling temperature and / or for a given cooling duration. The step of cooling allows to switch from a heated composite (i.e. hollow body) to a cooled composite that is easier to handle .

[0152] ccording to an embodiment, the cooling temperature and / or the cooling duration may be selected in accordance with the glass transition temperatures (Tg) and / or the melting temperature of the heated thermoplastic composite. Preferably, the step of cooling is at a cooling temperature below to a glass transition temperature of the heated thermoplastic composite. For example, the Tg may be below 130°C, preferably below 120 °C and more preferably below 110°C.

[0153] As mentioned, a method 100 according to the invention can comprise a step of coating 170 the composite layer. The step of coating may be implemented by a coating device such as a spray coating, a roller coating or a powder coating.

[0154] The step of coating allows to protect the hollow body against fire and / or impact. It is done directly after the winding or after the heating step or after the cooling step, preferably directly after the cooling step. These coatings could also be polymerized using photochemical sources. These coatings could also be polymerized using photochemical sources .

[0155] According to an embodiment the coating step is conduct after the heating step.

[0156] A step of coating may comprise the application of silica (SiCh) as interlayer and / or silica / titania (SiCh / TiCh) such as hybrid coatings as top layers as a sealing coating.

[0157] According to another aspect, the invention relates to a hollow body, preferably an axisymmetric hollow body, which is obtainable by a method according to the invention. More preferably, the invention relates to a hollow body, such as an axisymmetric hollow body, which is obtained by a method according to the invention.

[0158] The hollow body, such as an axisymmetric hollow body, according to the invention can be selected among: a tube, a storage tank, a vessel, a pressure vessel, a pipe, a storage tank under pressure or high pressure, utility poles, drive shaft, or wind turbine blades .

[0159] The hollow body according to the invention can comprise several layers, including a liner.

[0160] ccording to another aspect, the invention relates to the use of a hollow body, preferably an axisymmetric hollow body, according to the invention. The hollow body can be used as vessel, particularly pressure vessel.

[0161] In particular, the hollow body can be used in gas storage, gas transportation, water transportation, sewage transportation, aerospace components, or automotive components.

[0162] ccording to another aspect, the invention relates to a system for manufacturing a hollow body, preferably an axisymmetric hollow body comprising a layer of composite material according to the invention .

[0163] In particular, the system for manufacturing an axisymmetric hollow body can comprise an impregnation device, at least one UV light, a winding device, a heating device. The system for manufacturing a hollow body can comprise, a cooling device, a coating device .

[0164] The system may operate continuously or not, preferably continuously. Thus, the different elements and devices of the system can be configured to cooperate with each other. That is to say in order to work with each other.

[0165] The system may comprise an impregnation device. An impregnation device allows to impregnate a fibrous material with a polymeric composition, preferably with a polymer compositionaccording to the invention and as disclosed above . An impregnation device may be configured to wet fibers ( fibrous material ) through a polymeric composition and preferably a thermoplastic composition as disclosed above . For example , an impregnation device may comprise one or several bath, one or several inj ection chamber one or several soaking tanks , one or more impregnation chambers . The impregnation device can be configured to receive the fibers and to wet fibers by absorption or inj ection so as to ensure complete impregnation of the fibers with the thermoplastic composition, preferably in liquid form.

[0166] ccording to one embodiment , the impregnation device may comprise a comb , a wiper, a succession of rings of decreasing diameter, a tubular channel , so as to eliminate the excess of polymeric composition .

[0167] The system according to the invention may comprise at least one UV light such as UV lamps . The UV light is configured to expose the polymeric composition, preferably according to the invention to an UV light . An UV light may be configured to operate at a wavelength from 300 to 475 nm, preferably from 325 to 450 nm, more preferably from 350 to 425 nm. An UV light may be arranged upstream or downstream the impregnation device . An UV light allows to activate the photoinitiator in order to initiate the polymerization . Advantageously, the UV light may be configured to operate according to a duration which is longer than a duration of the heating device .

[0168] A system according to the invention comprises a winding device . A winding device may be configured to wind the impregnated fibrous material around a mandrel .

[0169] A winding device may comprise at least one automated system comprising multi-axis control ( e . g . ranging from 3 to 6 axis ) allowing for complex winding patterns necessary for different tank geometries . The systems comprise usually computer numerical control over winding paths , angles , and tension . Several parameters can have an influence on the quality of the produced hollow body . Advantageously, the winding device may comprise a controller for the winding angle . A winding device may be configured to operate a hoop, helical or polar winding . Advantageously, the winding device may comprise a controller for the tension applying to the fiber .Accordingly, the winding device may be configured to ensure proper alignment and compaction without damaging fibers . Advantageously, the winding device may comprise a controller for the speed of winding process and degree of automation .

[0170] A system according to the invention comprises a heating device . A heating device may be configured to heat the winded fibrous material . The heating device may comprise an enclosure , a microwave source , an IR source (NIR / MIR) , an air blower and / or an induction source . The heating device should ensure a sufficiently uniform heating of the winded fibrous material in relatively short times .

[0171] Advantageously, the heating device may comprise one or more IR or thermometer type heating sensors in order to control the different heating temperatures and / or a timer, to control the heating duration . Advantageously, the heating device may be configured to heat the winded fibrous material to polymerize the layer of composite material according to a heating duration and / or according to a heating temperature . A heating device may be configured to operate at a heating temperature of 100 ° C or less , preferably about 90 ° C and more preferably about 80 ° C .

[0172] A heating duration may be predetermined according to the heat activated initiator . The heat activated initiator may have a half- life time at the heating temperature of at most the heating duration . The heating device may be configured to operate according to the winding duration . Advantageously, the heating device is configured so that the heating duration is shorter than the winding duration, allowing to reduce the number of heating devices or their capacity .

[0173] The heating device may be configured to heat the winded fibrous material while the winded fibrous material is motionless . Preferably, the heating device is configured to heat the winded fibrous material while the winded fibrous material is positioned vertically, e . g . the axis of symmetry of the winded fibrous material is perpendicular to the ground .

[0174] Advantageously, a system according to the invention may comprise a heating device configured to heat the winded fibrousmaterial continuously . Preferably, a system may comprise a heating device and a winding device configured to operate continuously, preferably with each other .

[0175] Advantageously, the system according to the invention may comprise at most as many heating devices as winding devices . Indeed, as the heating duration is shorter than the winding duration, the system requires less heating devices than prior art systems . In particular, after the winding is completed, the mandrel with the wound fibers can enter an in-line heating zone .

[0176] The system according to the invention may comprise a cooling device . A cooling device may be configured at a cooling temperature below to the glass transition temperature of the winded fibrous material , preferably of the fibrous material heated and winded .

[0177] A system according to the invention may comprise a coating device . A coating device may be configured to coat the layer of composite material preferably as disclosed above .

[0178] The invention can be the subj ect of numerous variants and applications other than those described above . In particular, unless otherwise indicated, the different structural and functional characteristics of each of the implementations described above should not be considered as combined and / or closely and / or inextricably linked to each other, but on the contrary as simple uxtapositions . In addition, the structural and / or functional characteristics of the various embodiments described above may be the subj ect in whole or in part of any different j uxtaposition or any different combination .

Claims

CLAIMS1. Method (100) for manufacturing a hollow body, preferably an axisymmetric hollow body, comprising a layer of composite material, said process comprising the following steps:- a step of providing (110) a polymeric composition;- a step of impregnating (120) a fibrous material with the polymeric composition;- a step of winding (130) the impregnated fibrous material around a mandrel, said winding being carried out for a winding duration; and- a step of heating (150) the winded fibrous material, said heating being carried out for a heating duration to polymerize the layer of composite material; wherein :- the polymeric composition comprises a combination of a photoinitiator and a heat activated initiator;- it further comprises a step of exposing (140) the polymeric composition to an UV light; and- the heating duration is shorter than the winding duration.

2. Method according to claim 1, wherein the step of heating (150) the winded fibrous material is carried out at a heating temperature and the heat activated initiator has a half lifetime at the heating temperature of the heating step (150) that is lower than the winding duration.

3. Method according to claim 1 or 2 , wherein the step of impregnation (120) is carried out at an impregnating temperature and the impregnating temperature is selected such that the heat activated initiator has a half-life time at the impregnating temperature higher than the winding duration.

4. Method according to any one of claims 1 to 3, wherein the step of heating (150) is carried out at a heating temperature and the heat activated initiator has a half-life time at the heating temperature of at most the heating duration.

5. Method according to any one of claims 1 to 4, wherein the heat activated initiator is selected among heat activated initiators having a half-life time at the heating temperature that is at least 10 times shorter than its half-life time at the winding temperature .

6. Method according to any one of claims 1 to 5, wherein the heat activated initiator is selected among heat activated initiators having a half-life time of less than 1 hour at a temperature of 150°C.

7. Method according to any one of claims 1 to 6, wherein the heating step (150) is carried out at a temperature of 100°C or less .

8. Method according to any one of claims 1 to 7, wherein the polymeric composition has a dynamic viscosity of more than 10 mPa*s and less than 5000 mPa*s as measured at 25°C.

9. Method according to any one of claims 1 to 8, wherein the fibrous material is selected among: carbon fibers or glass fibers .

10. Method according to any one of claims 1 to 9, wherein the contact of the impregnated fibrous material with the mandrel can be direct or indirect.

11. Method according to any one of claims 1 to 10, wherein the step of heating is carried out while the winded fibrous material is motionless .

12. Method according to any one of claims 1 to 11, wherein the step of heating is carried out while the winded fibrous material is positioned vertically, e.g. the axis of symmetry of the winded fibrous material is perpendicular to the ground.

13. Method according to any one of claims 1 to 12, wherein it further comprises, after the heating step, a step of coating.

14. Method according to any one of claims 1 to 13, wherein the hollow body is a tube, a storage tank, a pressure vessel, a pipe, a storage tank under pressure or high pressure, utility poles, drive shaft, or wind turbine blades.

15. Method according to any one of claims 1 to 14, wherein the hollow body comprise several layers, including a liner.

16. Method according to any one of claims 1 to 15, wherein the polymeric composition is a thermoplastic composition.

17. Method according to any one of claims 1 to 16, wherein the polymeric composition comprises a thermoplastic polymer from the family of polyamide, polyurea, polyacrylic, poly (aryl ether ketones) , polyimides, aromatic polyetherimides , polysulfides, polysulfones, polyolefins, polylactic acid, polyvinyl, polyvinyl alcohol, fluoropolymers, styrenes, cellulosics, polyester and / or polycarbonates.

18. Method according to the previous claim, wherein the thermoplastic composition comprises a (meth) acrylic polymer.

19. Method according to any one of claims 1 to 18, wherein the layer of composite material comprises from 20 % to 50 % in volume of a polymeric composition including (meth) acrylic polymers, and from 50 % to 80 % in volume of fibers.

20. Method according to the previous claim, wherein the layer of composite material comprises at most 35 % in volume of a thermoplastic matrix comprising (meth) acrylic polymer and at least 65 % in volume of fiber.

21. The method according to any one of claims 1 to 20, wherein the polymeric composition comprises from 0.1 percent to 5 percent by weight, preferably from 0.5 percent to 3 percent by weight, evenmore preferentially from 1 percent to 2 percent by weight, of photoinitiator ( s ) , relative to the total weight of the polymeric composition .

22. The method according to claim 21, wherein the photoinitiator is a radical photoinitiator chosen from the family of the phosphine oxides, such as, for example, diphenyl ( 2 , 4 , 6- trimethylbenzoyl ) phosphine oxide (TPO) , ethyl (2,4, 6- trimethylbenzoyl ) phenylphosphine oxide (TPO-L) and bis (2, 6- dimethoxybenzoyl ) -2 , 4 , 4-trimethylphenylphosphine oxide (BAPO) or the family of the thioxanthones, such as, for example, isopropylthioxanthone (ITX) , 2 , 4-diethylthioxanthone, 2,4- dimethylthioxanthone, 2-chlorothioxanthone and l-chloro-4- isopropylthioxanthone .

23. The method according to any one of claims 1 to 22, wherein the heat activated initiator is having a half-life time of less than 1 hour at a temperature of 150°C.

24. A hollow body obtained from a method according to any one of claims 1 to 20.

25. The hollow body according to claim 24 comprising several layers, including a liner.

26. The hollow body according to claim 21 being a tube, a storage tank, a vessel, a pressure vessel, a pipe, a storage tank under pressure or high pressure, utility poles, drive shaft, or wind turbine blades .

27. Use of a hollow body according to any of claims 24 to 26 in gas storage, gas transportation, water transportation, sewage transportation, aerospace components, or automotive components.

28. System for manufacturing a hollow body comprising a layer of composite material, said system comprising:- an impregnation device configured to wet a fibrous material with a polymeric composition, said polymeric compositioncomprising a combination of a photo initiator and a heat activated initiator,- at least one UV light configured to exposing the polymeric composition to an UV light ,- a winding device configured to wind the fibrous material around a mandrel according to a winding duration, and- a heating device configured to heat the winded fibrous material to polymerize the layer of composite material according to a heating duration, the heating duration being shorter than the winding duration .29 . System according to the claim 23 wherein it comprises at most as many heating devices as winding devices .30 . System according to the claim 23 or 24 , wherein the heating device and the winding device are configured to operate continuously .31 . The system according to any of claims 28 to 30 , wherein the heating device is configured to operate at a heating temperature of 100 ° C or less .

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