A method of coating a reinforcement fibre

Abstract

This invention relates to method of coating a reinforcement fibre (116), the method comprising: a) providing a dispersion (106) in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) mixing the dispersion in a container (100) using a mixing device (104); c) coating, at least in part, a set of reinforcement fibres with the dispersion by immersing at least a portion of the set of reinforcement fibres in an immersion position within the container, wherein the container comprises a debris accumulator (102), wherein a perforated portion of the debris accumulator is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion.

Description

[0001] A Method of Coating a Reinforcement Fibre

[0002] Technical field

[0003] The present invention relates to fibre-reinforced composite materials, in particular a method of coating a reinforcement fibre.

[0004] Background

[0005] Fibre-reinforced composite materials are generally manufactured by coating reinforcement fibres with a polymeric dispersion, which is subsequently melted to impregnate the fibres with the thermoplastic comprised in the dispersion. The reinforcement fibres are intended for subsequent shaping or layering. The reinforcement fibres may be unidirectional or woven, for example, wherein the polymeric / thermoplastic bonds the reinforcement fibres together during manufacture. The polymeric / thermoplastic dispersion is usually provided as a suspension or dispersion of particles in a liquid.

[0006] It is desirable that the reinforcement fibres are uniformly distributed within the fibre- reinforced composite material, and that the particles of the thermoplastic composition uniformly surround all the reinforcement fibres (i.e., to obtain uniform impregnation). The particles of thermoplastic provided in the coating dispersions are prone to settling or aggregating. It is therefore desirable to obtain a homogenous dispersion in which the particles of thermoplastic are evenly distributed. Homogenous dispersions are thus preferred because they provide a uniform coating on the reinforcement fibres.

[0007] In order to improve or obtain homogeneity in the dispersion, the dispersion may be mixed with a mixing device. However, regular maintenance of the mixing device is necessary in order to ensure a consistent level of homogeneity in the dispersion. This can cause disruption because the maintenance of a mixing device, and any other moving parts in the dispersion container, requires physical access to the moving parts, which conventionally requires that the production of the reinforcement fibres is halted. It is therefore desirable to provide an improved method of coating reinforcement fibres such that production efficiency can be improved. The embodiments described below are provided by way of example only and are not limiting of implementations which solve any or all of the disadvantages of known methods and apparatus which perform the coating of a reinforcement fibre.

[0008] Summary of the Invention

[0009] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description.

[0010] In a first aspect there is provided a method of coating a reinforcement fibre, the method comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) mixing the dispersion in a container using a mixing device; c) coating, at least in part, a set of reinforcement fibres with the dispersion by immersing at least a portion of the set of reinforcement fibres in an immersion position within the container, wherein the container comprises a debris accumulator, wherein a perforated portion of the debris accumulator is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion.

[0011] In a second aspect there is provided a coated reinforcement fibre produced according to method of the first aspect.

[0012] In a third aspect there is provided a method of providing a fibre-reinforced composite material, the method comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) mixing the dispersion in a container using a mixing device; c) coating, at least in part, a set of reinforcement fibres with the dispersion by immersing at least a portion of the set of reinforcement fibres in an immersion position within the container, thereby obtaining a set of coated reinforcement fibres; and d) melting at least some of the polymeric composition contained in the set of coated reinforcement fibres, thereby providing the fibre-reinforced composite material; wherein the container comprises a debris accumulator, wherein a perforated portion of the debris accumulator is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion.

[0013] In a fourth aspect there is provided a composite according to the third aspect.

[0014] In a fifth aspect there is provided a reinforced fibre coating apparatus comprising: a container arranged to contain a dispersion comprising particles of a polymeric composition comprising a first thermoplastic, the dispersion provided in a liquid comprising water; a mixing device disposed within the container; a debris accumulator comprising a perforated portion; wherein the container, when in use, is arranged to allow a set of reinforcement fibres to be immersed, in an immersion position, in a said dispersion contained within the container, and wherein the perforated portion is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion.

[0015] In a sixth aspect there is provided a process for removing debris fibres from a polymeric dispersion comprising: a) providing a container arranged to contain a liquid dispersion comprising water; b) providing a dispersion in the container, the dispersion being a liquid dispersion comprising water and wherein the dispersion comprises particles of a polymeric composition comprising a first thermoplastic and fibre debris; c) providing a debris accumulator, wherein a perforated portion of the debris accumulator is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion d) moving the perforated portion from the first position to the second position; wherein, in the second position, at least part of the perforated portion is not immersed in the dispersion thereby allowing accumulated fibre debris to be removed.

[0016] Brief Description of the Figures

[0017] The present disclosure will now be described by way of example with reference to the accompanying drawings, in which:

[0018] Figure 1 shows a profile cross-sectional view of an apparatus being used to coat a reinforcement fibre including an example of a debris accumulator;

[0019] Figure 2 shows a perspective view of the apparatus for coating a reinforcement fibre as shown in figure 1 absent a debris accumulator;

[0020] Figure 3 shows a perspective view of the apparatus for coating a reinforcement fibre as shown in figure 2, including a debris accumulator in a configuration providing protection for the mixing device; and

[0021] Figure 4 shows a perspective view of the apparatus for coating a reinforcement fibre as shown in figure 2, including a debris accumulator in a configuration that allows cleaning.

[0022] The accompanying drawings illustrate various examples. The skilled person will appreciate that any illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the drawings merely represent one example of the boundaries or dimensions of the objects or elements shown. It may be that in some examples one element may be designed as multiple elements or vice versa that multiple elements may be designed as one element.

[0023] Detailed Description

[0024] In a first aspect there is provided method of coating a reinforcement fibre, the method comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) mixing the dispersion in a container using a mixing device; c) coating, at least in part, a set of reinforcement fibres with the dispersion by immersing at least a portion of the set of reinforcement fibres in an immersion position within the container, wherein the container comprises a debris accumulator, wherein a perforated portion of the debris accumulator is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion.

[0025] A problem with the coating of reinforcement fibres is that the particles of the polymeric composition are suspended, and not dissolved, in the dispersion. The particles are prone to settling at the bottom of the container and / or flocculating and / or clumping. In order to maintain a substantially homogeneous distribution of particles in the dispersion, mixing devices are used to mix and / or disturb the dispersion to prevent the settling or agglomeration of particles. The mixing devices are preferably rotary mixers, though any suitable mixing device capable of agitating the suspension so as to maintain particles in a substantially uniform suspension may be used.

[0026] A second known problem during the coating part of the manufacture of reinforcement fibres is that the sets of fibres produce a non-negligible amount of fibre debris. Although undesirable, fibre debris can be difficult to mitigate entirely. Debris production is caused by several factors, for example, due to tensioning of the fibres. In particular, the overtensioning of fibres can exacerbate the problem. Furthermore, fibres, and in particular carbon fibres, have a tendency to expel debris when moved from a wound position (e.g., from being stored in a wound position on a bobbin) to a straight, tensioned, position. Fibre debris therefore accumulates in the dispersion during the coating of the fibres.

[0027] Consequently, the mixing devices can become entangled in, or otherwise impeded by, the fibre debris. Conventionally, it is necessary to regularly maintain and clean the mixing devices to remove accumulated fibre debris, and thereby ensure that the mixing devices can operate as intended to maintain a homogenous suspension / dispersion. However, maintenance of the mixing devices disrupts the production of the reinforcement fibres. This is because the position of the fibres within the container obstructs access to the mixing devices. Thus, fibres cannot be coated in the container whilst maintenance is ongoing. Therefore, it is desirable to reduce the amount of fibre debris that accumulates in the dispersion in order that production efficiency can be improved. Even if the position of the fibres in the container does allow access to the mixing device, the mixing device needs to be turned off for cleaning which means the polymeric dispersion is not mixed during the cleaning process. This can impact the quality of the resulting coated fibres as the distribution of the polymer in the dispersion may be less uniform.

[0028] A third problem is that some methods of removing fibre debris from the dispersion disrupts production of the reinforcement fibres. For example, sieving the dispersion to remove fibre debris, and / or re-filling the container would necessarily prevent sets of fibres from being coated in the container. Fibre debris can also be removed from the container in-situ, e.g., by inserting a gauze or sieve to remove the debris. However, this typically cannot be done whilst coating of the fibres is ongoing, because the fibres would obstruct the gauze or sieve, and thus may become damaged. The removal of fibre debris is therefore a disruptive task. It would be advantageous if this disruption could be reduced.

[0029] Therefore, the inventors have established a method by which fibre debris can be removed from the dispersion without interrupting the production of the reinforcement fibres. Moreover, the inventors have established a method by which the fibres can be continuously collected whilst the coating of the fibres proceeds as normal. Consequently, and advantageously, the efficiency of producing reinforcement fibres is dramatically increased because the fibres can be both collected and removed from the dispersion without disrupting the coating of the fibres. Moreover, the continuous collection of fibre debris reduces the amount of fibre debris that accumulates on the mixing device. Therefore, the mixing device requires less frequent cleaning, thus further improving the production efficiency of the presently-disclosed method.

[0030] The first aspect achieves these advantages by providing a debris accumulator, preferably wherein the debris accumulator is configured, when in the first position, to accumulate fibre debris originating from the set of reinforcement fibres. Preferably a perforated portion of the debris accumulator is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion. The first position of the debris accumulator may otherwise be thought of as an operational position. The debris accumulator is preferably deployed in this operational position for the majority of the time when the coating of the set of reinforcement fibres is taking place, e.g., at least about 75% of the time, and preferably at least 90% or even at least 99% of the time. The positioning of the perforated portion of the debris accumulator between the sets of fibres (i.e. , when the fibres are submerged in the dispersion) and the mixing device provides protection to the mixing devices. Beneficially, a substantial amount of fibre debris expelled from the sets of reinforcement fibres is caught by the perforated portion. Advantageously, by being perforated, the debris accumulator does not impede the ability of the mixing device to uniformly distribute particles within the dispersion. In other words, the perforations allow the dispersion to freely pass through such that particles (of polymeric composition) are uniformly distributed throughout the dispersion and thus coat the fibres easily. Nevertheless, the size of the perforations are preferably chosen such that they protect the mixing devices by catching and accumulating the majority of fibres debris. Preferably, the majority (more than 50%) of fibre debris expelled from the fibres is caught by at last the perforated portion of the debris accumulator. More preferably more than about 75% of the fibre debris is caught, and more preferably still at least about 90% of the fibre debris is caught. By catching the debris, the debris accumulator prevents fibre debris from impeding and / or entangling the mixing devices.

[0031] The debris accumulator is movable to a second position in which at least part of the perforated portion is not immersed in the dispersion. This second position may otherwise be referred to as a ‘cleaning’ position. In this second position, the perforated portion sits proud of the surface of the dispersion, thus collected fibre debris collected can be removed either by hand or automatically. After cleaning, the perforated portion can be re-deployed to the first, ‘operational’, position. Advantageously, moving from the first to the second position, and the cleaning of the debris accumulator can be performed as frequently as needed since these actions do not interrupt the coating of the set of reinforcement fibres. Thus, fibre debris can be continually collected from the dispersion and subsequently removed without halting production of the reinforcement fibres.

[0032] Preferably, the debris accumulator is configured, when in the first position, to accumulate fibre debris originating from the set of reinforcement fibres. Thus, the debris accumulator is configured to collect fibre debris from the set of reinforcement fibres after the fibres are expelled from the set of reinforcement fibres, but before the debris reaches the mixing device.

[0033] Preferably, the perforated portion of the debris accumulator comprises a mesh layer, preferably a grid. A mesh or grid provides an advantageously uniform protection from fibre debris and moreover allows fibre debris to become tangled on the mesh layer rather than around the mixing device. Furthermore, having a uniform distribution of gaps / holes in a mesh allows for the dispersion to freely pass through, thereby allowing the dispersion to be easily mixed despite the placement of the debris accumulator.

[0034] Preferably, the debris accumulator is configured to be reversibly deployed by a driving mechanism. This has the benefit that the debris accumulator can be moved from the first to the second position without interfering with any other components (e.g., the container, the mixing device, or the positioning of the reinforcement fibres etc). Furthermore, since the debris accumulator may be driven between the two positions, the need to submerge external objects, e.g., a gauze, into the dispersion is obviated. The driving mechanism may be manually operated (e.g., a crank and handle) or may be automated and / or motorised. Preferably, the driving mechanism is operated externally from the container, e.g., by a handle and crank fixed to an exterior of the container.

[0035] Preferably, the method comprises moving, by the driving mechanism, the perforated portion of the debris accumulator from the first position to the second position thereby allowing accumulated fibre debris to be removed. Accumulated fibre debris can thus be collected directly from the dispersion and subsequently removed. No manual intervention with the dispersion itself need take place, since fibre debris can be transported directly out of the dispersion. Since at least a part of the perforated portion is not immersed in the dispersion (i.e., sits proud of the dispersion liquid), the transported fibre debris can easily and quickly be removed. The driving mechanism may then quickly redeploy the perforated portion to the first position where it can resume protecting the mixing device from the fibre debris.

[0036] Preferably, the debris accumulator is formed from a belt. In other words, the debris accumulator is formed of a continuous loop. Preferably the loop can be moved in both directions (i.e., clockwise or anticlockwise). Preferably the belt engages with at least one rotatable gear that forms part of the driving mechanism. Preferably the belt comprises a movable track. Preferably, the belt is formed of a mesh or grid, further preferably made of metal. A belt allows easy locomotion of the perforated portion from the first position to the second position, and vice versa. Furthermore, the use of a belt causes minimal disturbance to the coating process and the mixing of the dispersion, since only the surface of the belt moves through the dispersion (in contrast to, for example, the entire body of a gauze or sieve). Yet further, in some examples, the entire length, or substantially the entire length, of the belt may form the perforated portion. Optionally, the loop of the belt could be arranged such that part of the belt is submerged and disposed in the operational position, and part of the belt is not submerged / immersed in the dispersion. In other words, part of the belt may permanently be positioned in the second, cleaning, position. In this example, the belt could be configured to move frequently, or even continuously, such that fibre debris is continually caught and transported away from the dispersion to be cleaned or removed when in the second position. This has the advantage that fibre debris is never or rarely allowed to accumulate to the level that it impedes the mixing device. Moreover, the continuous operation of the belt would not interrupt or disturb the coating of the reinforcement fibres.

[0037] Preferably, the perforated portion is defined by a first length of the debris accumulator which extends across substantially the width of the container. Thus, preferably, in the first position, the first length is disposed between the mixing device and the immersion position of the set of reinforcement fibres, thereby protecting the mixing device. Since the first length extends across substantially the width of the container, it is relatively unlikely that fibre debris can evade the perforated portion, i.e., there is substantially no path for the fibre debris to reach the mixing device. Preferably, little or no gap exists between the edges of the perforated portion and the walls of the container, such that there is substantially no way for the fibre debris (other than microscopic amounts) to reach the mixing device.

[0038] Preferably, when the first position, the perforated portion of the debris accumulator forms two perforated layers, each layer disposed between the mixing device and the immersion position of the set of reinforcement fibres. In this way, any fibre debris that is not collected by the perforated layer closest to the immersion position (of the fibres) is instead collected by the second layer of the perforated portion. Thus, the perforated portion provides even greater protection for the mixing devices against suspended fibre debris when formed of two layers. The two layers of the perforated portion may be formed, for example, when the debris accumulator is a belt, wherein the loop of the belt comprises two overlapping layers.

[0039] Preferably, a second length of the debris accumulator comprises at least two separate tracks, the second length thereby forming an opening that extends across at least a portion of the width of the container. Preferably, when the perforated portion is not deployed in the first (operational) position, the opening formed by the second length is disposed over the mixing device thereby allowing access to the mixing device. In other words, when in the second (cleaning) position, the position of the debris accumulator allows access to the mixing devices. The opening in the second length, for example, may be in the centre of the debris accumulator and may represent about 50% to about 80% or even about 90% of the width of the container.

[0040] Preferably, the method comprises moving at least a portion of the set of reinforcement fibres through the dispersion in the immersion position, and removing the set of reinforcement fibres from the dispersion. In other words, the set of reinforcement fibres is immersed in and transported through the dispersion such that, once removed, the fibres are coated in the particles of the polymeric composition. Preferably, the set of reinforcement fibres is continuously fed into the dispersion, preferably at a constant speed, and thus continuously transported through the dispersion and subsequently removed. The speed at which the fibres are drawn through the dispersion, in units of linear meters per minute (or miinear / min) is in the range of about 2 miinear / min to about 20 miinear / min, preferably about 4 miinear / min to about 15 miinear / min. It will be appreciated that the distance dimension of “linear meters” defines a length of fibre and / or tape, and does not necessarily define a distance or displacement travelled in 3 dimensional space.

[0041] Preferably, the method comprises moving at least a portion of the set of reinforcement fibres through the dispersion, thereby causing the set of reinforcement fibres to become coated with particles of the polymeric composition. Preferably, substantially all fibres of the immersed reinforcement fibres become coated with the polymeric composition, preferably at least 90%, more preferably at least 95%, more preferably still at least 99%. Preferably, the spaces between the fibres, as well as the surface of the set of reinforcement fibres, become impregnated with particles of the polymeric composition. The method may comprise moving at least a portion of the set of reinforcement fibres thereby causing fibre debris to be expelled from the reinforcement fibres into the dispersion. Preferably, the perforated portion of the debris accumulator is configured to collect at least a part of the fibre debris. Preferably, the fibre debris expelled into the dispersion represents a substantially minor part of the set of reinforcement fibres, preferably less than about 10%, more preferably less than about 5%, more preferably still less than about 1 %. More preferably, all or substantially all of the fibre debris lost from the set of reinforcement fibres is caught by the perforated portion of the debris accumulator. Preferably, at least about 90%, more preferably at least about 95% or even about 99% of the fibre debris expelled / lost from the set of reinforcement fibres is caught by the perforated portion of the debris accumulator.

[0042] Preferably, moving at least a portion of the set of reinforcement fibres through the dispersion comprises tensioning the set of reinforcement fibres when in the immersion position. Tensioning the fibres allows greater control over the passage of the fibres through the dispersion, and allows control of the configuration of the fibres. Preferably, the fibres are preferably tensioned into a flattened tape-like formation prior to being coated by the dispersion. This confers the advantage that a greater surface area of the fibres becomes coated.

[0043] Preferably, the debris accumulator is configured to be reversibly deployed between the first and the second position without interfering with the moving of the portion of the set of reinforcement fibres through the dispersion in the immersion position. Advantageously, this provides that fibres can be removed whenever required, or even continuously removed, without interrupting the coating of the set of reinforcement fibres. As mentioned, the continuous removal of fibres prevents a build-up of fibre debris in the dispersion, thereby preventing clumps of fibre debris from impeding the mixing devices. Thus, the production efficiency of the reinforcement fibres can be dramatically improved. Preferably, the debris accumulator comprises metal, including when the debris accumulator is a belt. Preferably, the perforated portion of the debris accumulator is also metal. However, the material of the debris accumulator should not generally affect its ability to capture / catch loose fibre debris. Therefore, any suitable material that can be formed into a mesh and / or grid with suitable perforations would be suitable. For example, the mesh / grid may comprise plastic, for example, plastic woven into twine to form a net or webbing. Preferably, the mixing device is disposed below the perforated portion of the debris accumulator when in the first position. Preferably, the mixing device is disposed at the base of the container. Thus, the fibre debris, when expelled from the reinforcement fibres, is distant from the mixing device. Fibre debris would otherwise slowly settle towards the bottom of the dispersion, e.g., under gravity. Thus, by positioning the mixing device below the perforated portion of the debris accumulator, the fibre debris is preferably caught by the perforated portion before it can reach the mixing devices.

[0044] Preferably, the mixing device comprises at least one rotary mixer, preferably about one to about ten rotary mixers, more preferably about two to about eight rotary mixers. Rotary mixers provide good mixing of the dispersion, thereby producing an advantageously homogenous distribution of particles of the polymeric composition throughout the dispersion. Merely for example, the rotary mixer may comprise a rotary blade or other rotatable object, preferably driven to rotate by a motor.

[0045] Preferably, the set of reinforcement fibres comprises non-metal fibres including fibres selected from the group of glass fibres, carbon fibres, aramid fibres, Ultra-High Molecular Weight Polyethylene (UHMwPE) fibres, basalt fibres, and combinations thereof, preferably carbon fibres. Preferably, the set of reinforcement fibres may be carbon fibres such as aerospace or industrial grades including standard, intermediate, and high modulus fibres. For example, the tensile strength of suitable fibres may be in the range of about 4400 MPa to about 8000 MPa. The tensile modulus of suitable fibres may be in the range of about to about 230 GPa to about 600 GPa. In other examples, the set of reinforcement fibres may be glass fibres such as A-glass, E-glass, E-CR-glass, C- glass, D-glass, R-glass, S- glass, S-2-glass and HS-glass. In other examples, the set of reinforcement fibres may be aramid fibres such as Kevlar (RTM), Nomex (RTM) and Technora (RTM). In yet further examples, the set of reinforcement fibres may be ultra-High Molecular Weight Polyethylene (UHMwPE) fibres such as Dyneema (RTM), or basalt fibres such as Basfiber (RTM) or Wking (RTM) Super B. The set of reinforcement fibres may comprise fibres selected from any of the groups of fibres described above and / or mixtures thereof.

[0046] Preferably, the first thermoplastic is selected from a group comprising acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polycarbonate (PC), polyamide (PA), polystyrene (PS), high-density polyethylene (HDPE), PC / ABS, polyethylene terephthalate (PETG), polyphenylsulfone (PPSU), high impact polystyrene (HIPS), polytetrafluoroethylene (PTFE), lignin, rubber, and / or a polyaryletherketone (PAEK). Preferably, the first thermoplastic comprises PAEK. More preferably still, the PAEK comprises polymers selected from the groups of polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketoneetherketoneketone (PEKEKK), polyetherimide (PEI), polyetherdiphenyletherketone (PEDEK), and combinations thereof, more preferably the PAEK comprises a PEEK or a PEEK / PEDEK copolymer and combination thereof.

[0047] Preferably, the PEEK polymer has a repeat unit of formula I:

[0048] -O-Ph-O-Ph-CO-Ph- wherein Ph represents a phenylene moiety. In this embodiment, all phenylenes are 1 ,3- and I or 1 ,4-substituted to the adjacent ether and / or carbonyl groups.

[0049] Preferably, the PEDEK polymer has a repeat unit of formula II

[0050] -O-Ph-Ph-O-Ph-CO-Ph- wherein Ph represents a phenylene moiety and wherein the repeat units I and II are in the relative molar properties l:ll of from 6555:3545 to 95:5. In this example, all phenylenes are 1 ,3- and I or 1 ,4-substituted to the adjacent ether and / or carbonyl groups.

[0051] In a second aspect there is provided a coated reinforcement fibre produced according to method of the first aspect. Advantageously, since the dispersion is frequently or continuously cleaned of fibres, fibres are prevented from accumulating to a degree such that they form agglomerates or clumps in the dispersion. Consequently, the coated reinforcement fibres are substantially defect free in the sense that they are substantially free form unwanted debris or loose fibre strands. Furthermore, the ability to efficiently clean / remove fibres from the dispersion, together with the benefit that the mixing devices need cleaning of fibre debris far less frequently, results in a more consistent quality of coated reinforcement fibres due to fact that production of the fibres is interrupted far less frequently. Moreover, throughout of the produced coated reinforcement fibres is greater since the coating process need not be halted as frequently for maintenance and cleaning.

[0052] In a third aspect there is provided a method of providing a fibre-reinforced composite material, the method comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) mixing the dispersion in a container using a mixing device; c) coating, at least in part, a set of reinforcement fibres with the dispersion by immersing at least a portion of the set of reinforcement fibres in an immersion position within the container, thereby obtaining a set of coated reinforcement fibres; and d) melting at least some of the polymeric composition contained In the set of coated reinforcement fibres, thereby providing the fibre-reinforced composite material; wherein the container comprises a debris accumulator, wherein a perforated portion of the debris accumulator is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion.

[0053] The fibre-reinforced composite material is substantially defect-free due to the fact that unwanted fibre debris is removed from the dispersion effectively. Thus, fibre debris does not become integrated into the composite material. Again, the fibre-reinforced composite material is of an advantageously consistent quality due to the fact that production of the fibre-reinforced composite material can be interrupted far less frequently, or preferably never.

[0054] In a fourth aspect there is provided a composite according to the third aspect.

[0055] In a fifth aspect there is provided a reinforced fibre coating apparatus comprising: a container arranged to contain a dispersion comprising particles of a polymeric composition comprising a first thermoplastic, the dispersion provided in a liquid comprising water; a mixing device disposed within the container; a debris accumulator comprising a perforated portion; wherein the container, when in use, is arranged to allow a set of reinforcement fibres to be immersed, in an immersion position, in a said dispersion contained within the container, and wherein the perforated portion is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion. In a sixth aspect there is provided a process for removing debris fibres from a polymeric dispersion comprising: a) providing a container arranged to contain a liquid dispersion comprising water; b) providing a dispersion in the container, the dispersion being a liquid dispersion comprising water and wherein the dispersion comprises particles of a polymeric composition comprising a first thermoplastic and fibre debris; c) providing a debris accumulator, wherein a perforated portion of the debris accumulator is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion d) moving the perforated portion from the first position to the second position; wherein, in the second position, at least part of the perforated portion is not immersed in the dispersion thereby allowing accumulated fibre debris to be removed. In other words, in the second position, the fibres debris can be cleaned from the surface of the perforated portion of the debris accumulator. The perforated portion may then be re-deployed to the first position to continue collecting any fibre debris contained within the dispersion.

[0056] The above-described features may be combined as appropriate, as would be apparent to a skilled person, and may be combined with any of the aspects of the examples described herein.

[0057] Examples

[0058] An example of a debris accumulator is now described with reference to the accompanying figures. Other examples related to the composition of the dispersion and details of the manufacturing process for coating reinforcement fibres are also described, merely for context.

[0059] Figure 1 shows an example apparatus for coating a reinforcement fibre. The apparatus comprises a container 100, a debris accumulator 102, and mixing devices 104 in the form of rotary mixers. The debris accumulator 102 in this example is a continuous belt. Figure 1 shows that the belt 102 is fixed to the container via on a series of axles 108, 112, 114. The topmost axle 108 comprises a gear that engages with the belt of the debris accumulator 102 such that the belt can be moved from one position to another, and / or continuously cycled. The gear axle 108 may be operated (i.e. , rotated) by a manual crank and handle (not shown), or may be motorised. Axle 112 and axle 114 may be idle, i.e., they are not arranged to drive the belt, but rotate with the motion of the belt. Alternatively, axles 112 and 114 may simply be metal bars over which the belt passes. A pair of guide pins 110 may be included to tension / urge the belt into the configuration shown. It will be appreciated that the illustration is not intended to be to scale, and nor are the relative distances necessarily representative of true examples. For example, the top of the belt 102 as it passes over the gear 108 may sit proud of the upper lip of the container, and / or may extend out beyond the left side of the container. Alternatively, a section of the container may be removed so as to expose the upper portion of the belt around the gear. For example, exposing a portion of the belt forming the debris accumulator facilitates access to the belt for cleaning away accumulated fibre debris.

[0060] Figure 1 indicates an example position of the dispersion 106 within the container 100. The level of the dispersion indicated is such that part of the debris accumulator 106 is submerged, and part is not submerged. Also indicated is an example path that may be taken by the reinforcement fibre 116. The reinforcement fibres 106 are shown being guided through the container and dispersion by guide rails 118a, 118b, 118c, 118d. These guide rails are optional, and may be fixed to the container, or may be separate, external, guide rails. Though not shown, the set of fibres 116 indicated are preferably formed of several separate reels of fibre. The number of reels used is, in general, independent of other parameters disclosed herein. For example, between about 4 and about 400 separate reels may be used in different examples. Preferably, the reels of fibres are congregated into a flattened structure resembling a length of tape.

[0061] The number of carbon filaments on each reel also varies, for example, the length of fibre in each reel may comprise thousands of individual strands (or filaments), for example, between about 1000 and about 50000 filaments of fibre, preferably between about 6000 to about 24000. Nevertheless, in some examples, e.g., where a large number of reels (e.g., more than 100 or 200 reels) is used, fewer than 5000 filaments per reel may be used. Merely for example, where more than 100 reels are used, the number of filaments per reel may be in the range of about 1000 to about 5000. It will nevertheless be understood that the total number of filaments (i.e., the total number of filaments across all reels) used to form the length of reinforcement fibre 116 depends at least in part of the width and / or thickness of the composite being produced from the reinforcement fibre 116.

[0062] The fibres 116 are preferably fed from a storage position (not shown, e.g., having been wound onto bobbins or creels) and congregated prior to being guided through the dispersion 106. As can be seen, the guide rails 118a, 118b, 118c, 118d lead the set of fibres 116 through the dispersion such that the fibres become entirely immersed. Generally, any position (or range of positions) at which part of the reinforcement fibre is immersed may be referred to as an ‘immersion position’. The fibres are then led out of the dispersion, at which point they are coated with particles of the polymeric composition that were suspended in the dispersion.

[0063] As illustrated in figure 1 , the debris accumulator is preferably positioned in the dispersion such that it intervenes between the immersion position of the fibres 116 and the set of rotary mixers 104. Consequently, any fibre debris expelled is preferably caught by the debris accumulator 102. In some examples, substantially all of the debris accumulator 102, e.g., the full length of the loop / belt, may be formed of a perforated material such as a mesh or grid. Consequently, the belt is permanently configured in an ‘operational’ position that can catch fibre debris. In this case, the belt may be frequently rotated such that the portion of the belt underneath the immersion portion (for example, the portion of the belt between guide pin 110 and axle 112) can carry away any accumulated fibre debris. Upon movement of the belt, the accumulated fibre debris is led out of the dispersion towards the exposed (i.e. , non-immersed) area next to the gear 108, where the debris may be removed. Removal of the debris may be done by hand, or may be removed by removal means such as a scraper, brush, water stream or jet, or other suitable cleaning mechanism. In some cases, the belt may be arranged such that collected fibre debris simply falls out of the container (e.g., via a chute, not shown) by gravity during rotation of the belt. It should be appreciated that, in use, the fibres 106 that are immersed in, and pass through, the dispersion do not contact any part of the debris accumulator.

[0064] Figure 2 shows a plan view of the apparatus for coating a reinforcement fibre shown in figure 1 , in which the debris accumulator, dispersion, and set of fibres are not shown. The illustrated container 100 has four rotary mixers, which form the mixing device. The rotary mixers are configured to mix the dispersion to ensure a homogenous distribution of particles, and to prevent settling and / or clumping of particles of polymeric composition in the dispersion. Consequently, it is preferable to have several rotary mixers, for example between about one and ten, more preferably between two and eight. Figure 2 illustrates two gears 108 on both sides of the container, configured to engage with the debris accumulator so as to move the perforated portion. Also illustrated is a crank 200, by which the debris accumulator can Be moved via the gear axle 108. For example, the crank may be connected to a handle which is manually operated so that the debris accumulator can be cleaned periodically, e.g., as frequently as needed. The frequency of cleaning may depend on the type or quantity of reinforcement fibres being used.

[0065] Figure 3 shows a plan view of the apparatus for coating a reinforcement fibre shown in figure 1 , with an example of a debris accumulator. The debris accumulator here 102 is a belt that loops around the axles 112, 108 at either end of the container. The debris accumulator shown is formed of two sections or lengths. The first length, shown on the right-hand side of the container 100, is formed of a full-width mesh. This first length forms the perforated portion of the debris accumulator. It will be understood that ‘full-width’ refers to extending across substantially or all of the width of the container, leaving substantially no gap. The mesh belt 102 loops around the right-hand axle 112 such that two layers of mesh are disposed between the immersion position of the fibres (as indicated in figure 1) and the rotary mixers 104. In this example, the perforated portion of the debris accumulator 102 is formed by this full-width length of the belt 102. It will be appreciated that the width of the belt is designed to substantially match the width of the container 100. However, in some examples, a small clearance may be left merely to allow smooth operation of the belt. The second length of the debris accumulator is on the left-hand side of the container 100 and is formed of two tracks. The tracks may be made of the same mesh as the full-width part of the belt 102. The two tracks form an opening in the second length of the debris accumulator.

[0066] In Figure 3, the first, full-width, length of the debris accumulator 102, i.e., the perforated portion, is disposed over the mixing device. Thus, figure 3 illustrates the operational position 300 (elsewhere referred to as the “first position”) of the debris accumulator. When in this operational position, the second length of the belt having the central opening does not necessarily perform any function. In use, the full-width length of the belt 102 is configured to catch / accumulate fibre debris. Figure 4 shows a plan view of the apparatus for coating a reinforcement fibre shown in figure 3, having the same debris accumulator 102 formed of two lengths. Here, the debris accumulator is illustrated in the cleaning position 400 (elsewhere referred to as the ‘second’ position). It will be appreciated that, since the debris accumulator is formed of a belt on a continuous loop that can be driven by the driving axle 108 and crank 200, the perforated portion formed by the ‘full-width’ length of the debris accumulator 102 can be easily and reversibly moved from the first, operational, position in figure 3 to the second, cleaning, position in figure 4. It should be appreciated that any fibre debris collected by the full-width length of the belt will be raised above the surface level of the dispersion such that the debris can be removed. Debris may be removed either by hand, though may in some examples fall away under gravity. Debris may also be removed using a fixed- position scraper, water stream / jet, brush, or other suitable automated or fixed cleaning device that would be within the remit of the skilled person to devise. Although not shown in the plan view perspective of figures 3 and 4, the debris accumulator 102 is intended to have the same angled configuration as shown in the debris accumulator of figure 1. Thus, although not shown, the left-hand side of the debris accumulator in the vicinity of the driving axle 108 will, in use, be exposed above the surface of the dispersion liquid.

[0067] In the cleaning position 400, in addition to the fact that debris can be removed / cleaned from the full-width part of the track, the debris accumulator shown with the opening in its second length has the advantage that access to the mixing devices is provided. Consequently, when in the cleaning configuration 400, the rotary mixers 104 at the base of the container may be maintained or cleaned. For example, fibre debris that has accumulated on the rotary mixers may be removed by hand. Such cleaning of the rotary mixers 104 may require halting the coating of fibres temporarily, i.e. , so that the fibres do not obstruct access. The dispersion is also preferably emptied from the container to allow visibility / access. Nevertheless, the advantage of the debris accumulator 102 is that it can remain in-situ while the rotary mixers are cleaned. Thus, the debris accumulator 102 can permanently remain as part of the container. Furthermore, the belt of the debris accumulator 102 can be rotated through a complete cycle such that the full extent of the belt (including both the first and the second lengths) can be cleaned in-situ, without the need to drain the dispersion from the container.

[0068] During operation, the debris accumulator 102 is cleaned as often as necessary. Beneficially, since cleaning the debris accumulator does not disrupt the ongoing production / coating of reinforcement fibres, it can be regularly cleaned in order to prevent the buildup of debris in the dispersion and / or around the rotary mixers. For example, the perforated portion of the debris accumulator 102 may be cleaned about every 5 to 10 minutes. The perforated portion can also be regularly checked to determine whether it needs cleaning, and / or to determine how much fibre debris is accumulating. Filaments of the fibres, particularly when carbon fibres are used, are visible to the naked eye, and tend to agglomerate into lumps or sheets of fibre attrition. Thus, it is usually easy to determine when the debris accumulator needs cleaning of fibre debris.

[0069] The debris accumulator is preferably a mesh, and preferably also as a belt. As mentioned, the mesh belt may comprise a continuous track of full-width mesh along its entire length, or may contain an opening in one length to allow operational access to the rotary mixers. When the debris accumulator is a belt, the belt can preferably be moved to any arbitrary position in between the operational and cleaning positions. Therefore, the entire length of the debris accumulator, including the full extent of the ‘full-width’ perforated portion illustrated in figured 3 and 4, can be cleaned to remove collected fibre debris.

[0070] Preferably, the dimensions of the gaps in the mesh are about 6 mm by 80 mm. These dimensions are suitable for most types of fibre, though it will nevertheless be understood that different sized gaps would be suitable. In particular, when carbon fibres are used, once the strands of fibre become entangled on the mesh, the fibres themselves act as a filter which accumulates more fibres. Therefore, the initial mesh dimensions need not be too small. Generally, it is acceptable to allow small and microscopic fibre debris to remain in the dispersion, e.g., fibre debris of less than about 5 mm in dimension (i.e., length). The overall aim is to prevent large clumps of fibre attrition from becoming entangled on the rotary mixers and / or from coating the reinforcement fibres and thus causing defects.

[0071] There may be a trade-off in the selection mesh coarseness. For example, larger mesh gaps may allow the rotary mixers to more easily distribute and mix the dispersion to obtain homogeneity, but may not catch smaller dimensions of fibre debris. Conversely, mesh with smaller gaps is likely to catch a higher proportion of fibre debris including smaller and / or microscopic pieces of debris, though small gaps may impede the ability of the mixing device to mix the dispersion evenly. This trade-off would be apparent to the skilled person, who would be able to select a suitable mesh coarseness to balance the need to catch fibre debris with the need to provide good mixing. Balancing these variables may depend on factors such as the propensity of particles in the dispersion to settle and the amount of fibre debris generated by the coating process (which itself is dependent on the type or amount of fibre used), which would also be within the remit of the skilled person.

[0072] Specific example

[0073] In one example, a debris accumulator as shown in figures 3 and 4 was used, i.e. , having a first length being full width and forming a perforated portion, and second length having a central opening. The coating process was performed with carbon fibres, where the dispersion contained particles of PAEK, specifically containing PEEK polymer. The particle sizes of the PEEK polymer were between about 5 and about 25 pm. The proportion of polymer in the dispersion was between about 10% wt to about 40% wt, with the remaining liquid mainly being water and small amounts of anti-coagulation agents (examples of which are described below in more detail). The dispersion also contained a surfactant (suitable examples of which are provided below) to further encourage dispersion of the particles within the dispersion. Between about 15 to about 25 reels of carbon fibre were used to form the reinforcement fibre strands prior to coating, where each reel of carbon fibre contained about 12000 filaments. The reels of filaments were arranged, prior to coating, into a flattened tape structure.

[0074] Two experimental coating periods were performed. In each experiment, the fibres were drawn through the dispersion for coating at a constant speed, continuously, for 2 hours. The speed of the fibres, in units of linear meters per minute (miinear / min) when being drawn through the dispersion, was between about 4 miinear / min to about 15 miinear / min. In the first experiment the debris accumulator was kept in the second, ‘cleaning’, position 400 in which the rotary mixers were not protected by the debris accumulator. In the second experiment the debris accumulator was kept in the first, ‘operational’, position 300 in which the rotary mixers were protected by the perforated portion of the debris accumulator. Specifically, in the second experiment, since the debris accumulator is a belt, two layers of perforated mesh grid were disposed between the immersion position of the fibres (e.g., the position in which the fibres are drawn through the dispersion as indicated in figure 1) and the rotary mixers.

[0075] The amount of fibre debris accumulated on the rotary mixers was measured after each of the two-hour experiments. In the first experiment where the rotary mixers were exposed, 8.28 g of carbon fibre debris was collected. In the second experiment in which the rotary mixers were protected by the ‘operational’ position of the debris accumulator, only 1.88 g of carbon fibre debris was collected. This represents a reduction in the amount of fibre debris accumulating on the rotary mixers by a factor of 4.4. Any debris caught by the perforated portion of the debris accumulator can simply be removed without disrupting the production / coating of fibres. Therefore, the implementation of the exemplified debris accumulator can result in reducing the frequency at which the rotary mixers need to be cleaned by a factor of 4.4. Given that cleaning the rotary mixers can be a highly disruptive task, i.e., potentially requiring that the container be drained entirely, it should be appreciated that the reversibly deployable debris accumulator, which can be cleaned in- situ, can provide a dramatic improvement in production efficiency of reinforcement fibres.

[0076] Dispersion

[0077] The method comprises dispersing the particles of the first polymeric composition comprising the first thermoplastic in the liquid comprising water, thereby forming the dispersion.

[0078] In one example, dispersing the particles comprises suspending the particles in the liquid, wherein the dispersion comprises and / or is a suspension of the particles in the liquid. In one example, dispersing the particles in the liquid comprises forming a paste or a slurry using a part of the liquid and subsequently adding the remaining liquid and mixing, for example by stirring using a mixing device such as a rotary mixer, static mixing and / or vibrating, for example ultrasonically. In one example, dispersing the particles in a liquid comprises adding the particles to the liquid and mixing. In one example, dispersing the particles in the liquid comprises dispersing the particles in the liquid at a temperature in a range from about 5 °C to about 50 °C, preferably in a range from about 10 °C to about 40 °C, more preferably in a range from about 15 °C to about 30 °C, for example about 20 °C or about 25 °C, for example room temperature. In yet another example, the dispersion may be obtained pre-mixed, where the pre-mixed dispersion is simply poured into the container as described herein and mixed in-situ to evenly distribute the particles of the polymeric composition.

[0079] Preferably, the type of polymeric dispersion used in the dispersion according to present embodiments uses a first thermoplastic comprising polyaryletherketones (PAEK). Preferably, the proportion of PAEK polymer particles in the dispersion is in the range of about 5 wt.% to about 40 wt.% by weight of the dispersion liquid, preferably about 10% to about 40%, more preferably about 13% to about 40%.

[0080] In one example, the dispersion liquid comprises water in a range from about 60 wt.% to about 95 wt.%, preferably in the range of about 60 wt.% to about 87 wt.% by weight of the liquid. That is, the dispersion is an aqueous dispersion, thereby improving safety and / or environmental impact, compared with organic liquids.

[0081] Due to the low surface energy of PAEKs, they are normally not very well dispersed in water, and are prone to settling. Water alone cannot fully wet out the PAEK powder. Consequently, a dispersing agent may be used in order to improve the separation of the particles and to prevent their settling or agglomeration in the dispersion. Thus, in one example, the liquid comprises a dispersion agent, such as a surfactant, in a range from 0 wt.% to 20 wt.%, preferably in a range from about 0.1 wt.% to about 10 wt.%. In this way, a relatively more homogeneous dispersion of the particles in the dispersion may be achieved, for example by reducing particle agglomeration, and / or a relatively more stable dispersion, for example such that the particles do not settle or settle only relatively more slowly. For example, the dispersion agent I surfactant may improve the separation of the particles and / or prevent settling and / or clumping of the particles.

[0082] In one example, the dispersion agent I surfactant comprises and / or is Sodium lignosulfonate, 1-Methyl-2- pyrrolidone, Sodium polyacrylate, Butyl acetate, Polyethylene glycol, Xylene, 5-Chloro-2-methyl- 4-isothiazolin-3-one, Solvent naphtha (petroleum), Sodium hydroxide, Polyacrylic acid, Naphthalenesulfonic acid, 1-Hydroxyethane-1 ,1- diphosphonic acid, Formaldehyde, Sodium sulphate, 1 -Hexadecanol, 2-Methyl-4- isothiazolin-3-one, 1-Methoxy-2-propanol acetate, 1 ,2- Propanediol, 1 -Methoxylpropanol, Sodium Nitrate, Benzotriazole, sodium dioctyl sulfosuccinate, or a mixture thereof. In one preferred example, the dispersion agent comprises and / or is 1-Methyl-2- pyrrolidone, 1 -Methoxy- 2-propanol acetate, 1 ,2-Propanediol, 1-Methoxy-2-propanol, Sodium Nitrate, Benzotriazole, or a mixture thereof.

[0083] The liquid dispersion may also comprise other agents, for example, a thickening agent, a viscosity regulating agent, a resinous agent, a surfactant, or a mixture thereof, in a range from about 0 wt.% to about 20 wt.%, preferably in a range from about 0.1 wt.% to about 10 wt.%. Fibre-reinforced composite material

[0084] Preferably, the reinforcement fibres that are used to form composite materials have a diameter in a range from about 2 pm to about 100 pm, preferably in a range from about 3 pm to about 50 pm, more preferably in a range from about 4 pm to about 20 pm, most preferably in a range from about 4 pm to about 8 pm. Typically, suitable carbon fibres have a diameter in a range from about 4 pm to about 8 pm and suitable glass fibres have a diameter in a range from about 4 pm to about 20 pm.

[0085] In one example, the first set of reinforcement fibres comprises unidirectional and / or continuous fibres, for example having a length of at least about 10 m, at least about 100 m, at least about 1 km, at least about 10 km. In this way, relatively larger fibre-reinforced composite materials may be provided. In one example, coating, at least in part, the of reinforcement fibres with the dispersion comprises immersing the reinforcement fibres in the above-described dispersion, for example in a container as described and having the debris accumulator as described, preferably while tensioning the set of reinforcement fibres. In this way, a relatively more uniform coating is achieved.

[0086] Preferably, the first thermoplastic used in the polymeric composition in the dispersion is a PAEK polymer. More preferably, the first thermoplastic comprises a polyetheretherketone (PEEK) polymer, a polyetherdiphenyletherketone (PEDEK) polymer, a polyetherketone (PEK) polymer, a polyetherketoneetherketoneketone (PEKEKK) polymer or a copolymer of two or more thereof.

[0087] More preferably still, the first PAEK polymer comprises a PEEK polymer or a PEEK / PEDEK copolymer.

[0088] Preferably, the PEEK polymer has a repeat unit of formula I:

[0089] -O-Ph-O-Ph-CO-Ph- wherein Ph represents a phenylene moiety. In this embodiment, all phenylenes are 1 ,3- and I or 1 ,4-substituted to the adjacent ether and / or carbonyl groups.

[0090] Preferably, the PEDEK polymer and a repeat unit of formula II

[0091] -O-Ph-Ph-O-Ph-CO-Ph- wherein Ph represents a phenylene moiety and wherein the repeat units I and II are in the relative molar properties 1:11 of from 6555:3545 to 95:5. In this example, all phenylenes are 1 ,3- and I or 1 ,4-substituted to the adjacent ether and / or carbonyl groups.

[0092] Within this specification, the term "about" means plus or minus 20%, more preferably plus or minus 10%, even more preferably plus or minus 5%, most preferably plus or minus 2%. Within this specification, the term "substantially" means a deviation of plus or minus 20%, more preferably plus or minus 10%, even more preferably plus or minus 5%, most preferably plus or minus 2%.

[0093] Within this specification, reference to “substantially” includes reference to “completely” and / or “exactly”. That is, where the word substantially is included, it will be appreciated that this also includes reference to the particular sentence without the word substantially.

[0094] It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications are covered by the appended claims.

[0095] In this disclosure, when the subject of a phase is described as being "configured to" or “arranged to”, followed by a term defining a condition or function, this is used to indicate that the subject of the phrase is in a state in which it has that condition, or is able to perform that function, without the subject being modified or further configured.

[0096] Some implementations may be described using the expressions “one / an embodiment” or “one / an implementation” or “one / an example”, along with their derivatives. These terms mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in some implementations” in various places in the specification are not necessarily all referring to the same embodiment. Moreover, unless otherwise noted the features described above are recognized to be usable together in any combination. Thus, any features discussed separately may be employed in combination with each other unless it is noted that the features are incompatible with each other. The foregoing description of example embodiments has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the present disclosure be limited not by this detailed description, but rather by the claims appended hereto. Future filed applications claiming priority to this application may claim the disclosed subject matter in a different manner and may generally include any set of one or more limitations as variously disclosed or otherwise demonstrated herein. Within this specification embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the invention. For example, it will be appreciated that all preferred features described herein are applicable to all aspects of the invention described herein and vice versa. For example, all preferred features of the composite apply to all aspects of the invention.

Claims

CLAIMS1 . A method of coating a reinforcement fibre, the method comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) mixing the dispersion in a container using a mixing device; c) coating, at least in part, a set of reinforcement fibres with the dispersion by immersing at least a portion of the set of reinforcement fibres in an immersion position within the container, wherein the container comprises a debris accumulator, wherein a perforated portion of the debris accumulator is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion.

2. The method of claim 1 , wherein the debris accumulator is configured, when in the first position, to accumulate fibre debris originating from the set of reinforcement fibres.

3. The method of claim 1 or 2, wherein the perforated portion of the debris accumulator comprises a mesh layer, preferably a grid.

4. The method of any preceding claim, wherein the debris accumulator is configured to be reversibly deployed by a driving mechanism.

5. The method of claim 4, comprising moving, by the driving mechanism, the perforated portion of the debris accumulator from the first position to the second position thereby allowing accumulated fibre debris to be removed.

6. The method of any preceding claim, wherein the debris accumulator is formed from a belt.

7. The method of claim 6, wherein the perforated portion is defined by a first length of the debris accumulator which extends across substantially the width of the container.

8. The method of claim 6 or 7, wherein, when the first position, the perforated portion of the debris accumulator forms two perforated layers, each layer disposed between the mixing device and the immersion position of the set of reinforcement fibres.

9. The method of any of claims 6 to 8, wherein a second length of the debris accumulator comprises at least two separate tracks, the second length thereby forming an opening that extends across at least a portion of the width of the container.

10. The method of any preceding claim, comprising: moving at least a portion of the set of reinforcement fibres through the dispersion in the immersion position; and removing the set of reinforcement fibres from the dispersion.

11. The method of claim 10, wherein moving at least a portion of the set of reinforcement fibres through the dispersion causes the set of reinforcement fibres to become coated with particles of the polymeric composition.

12. The method of claim 10 or 11 , wherein moving at least a portion of the set of reinforcement fibres causes fibre debris to be expelled from the reinforcement fibres into the dispersion, wherein the perforated portion of the debris accumulator is configured to collect at least a part of the fibre debris.

13. The method of any of claims 10 to 12, wherein moving at least a portion of the set of reinforcement fibres through the dispersion comprises tensioning the set of reinforcement fibres when in the immersion position.

14. The method of any of claims 10 to 13, wherein the debris accumulator is configured to be reversibly deployed between the first and second position without interfering with the moving of the portion of the set of reinforcement fibres through the dispersion in the immersion position.

15. The method of any preceding claim wherein the mixing device is disposed below the perforated portion of the debris accumulator when in the first position.

16. The method of any preceding claims, wherein the mixing device comprises at least one rotary mixer, preferably about one to about ten rotary mixers.

17. The method of any preceding claim wherein the debris accumulator comprises metal.

18. The method of any preceding claim wherein the set of reinforcement fibres comprises non-metal fibres including fibres selected from the group of glass fibres, carbon fibres, aramid fibres, Ultra-High Molecular Weight Polyethylene (UHMwPE) fibres, basalt fibres, and combinations thereof, preferably carbon fibres.

19. The method of any preceding claim wherein the first thermoplastic is selected from a group comprising acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polycarbonate (PC), polyamide (PA), polystyrene (PS), high-density polyethylene (HDPE), PC / ABS, polyethylene terephthalate (PETG), polyphenylsulfone (PPSU), high impact polystyrene (HIPS), polytetrafluoroethylene (PTFE), lignin, rubber, and / or a polyaryletherketone (PAEK), preferably, the first thermoplastic comprises PAEK, preferably the PAEK comprises polymers selected from the groups of polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketoneetherketoneketone (PEKEKK), polyetherimide (PEI), polyetherdiphenyletherketone (PEDEK), and combinations thereof, more preferably the PAEK comprises a PEEK or a PEEK / PEDEK copolymer and combination thereof.

20. A coated reinforcement fibre produced according to any of the preceding claims.

21. A method of providing a fibre-reinforced composite material, the method comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) mixing the dispersion in a container using a mixing device; c) coating, at least in part, a set of reinforcement fibres with the dispersion by immersing at least a portion of the set of reinforcement fibres in an immersion position within the container, thereby obtaining a set of coated reinforcement fibres; andd) melting at least some of the polymeric composition contained in the set of coated reinforcement fibres, thereby providing the fibre-reinforced composite material; wherein the container comprises a debris accumulator, wherein a perforated portion of the debris accumulator is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion.22 A composite produced according to claim 21 .

23. A reinforced fibre coating apparatus comprising: a container arranged to contain a dispersion comprising particles of a polymeric composition comprising a first thermoplastic, the dispersion provided in a liquid comprising water; a mixing device disposed within the container; a debris accumulator comprising a perforated portion; wherein the container, when in use, is arranged to allow a set of reinforcement fibres to be immersed, in an immersion position, in a said dispersion contained within the container, and wherein the perforated portion is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion.

24. A process for removing debris fibres from a polymeric dispersion comprising: a) providing a container arranged to contain a liquid dispersion comprising water; b) providing a dispersion in the container, the dispersion being a liquid dispersion comprising water and wherein the dispersion comprises particles of a polymeric composition comprising a first thermoplastic and fibre debris; c) providing a debris accumulator, wherein a perforated portion of the debris accumulator is configured to be reversibly deployed between i) a first position between the mixing device and the immersion position of the set of reinforcement fibres and ii) a second position in which at least part of the perforated portion is not immersed in the dispersion d) moving the perforated portion from the first position to the second position;wherein, in the second position, at least part of the perforated portion is not immersed in the dispersion thereby allowing accumulated fibre debris to be removed.

25. A method of providing a fibre-reinforced composite material according to claim 21 , a composite according to claim 22, a reinforced fibre coating apparatus according to claim23 or a process for removing debris fibres from a polymeric dispersion according to claim 24, further comprising the feature of any of claims 2 to 21 .

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