A method of producing a fibre-reinforced composite

Abstract

This invention relates to a method of producing a fibre-reinforced composite tape (228) comprising: a) providing a dispersion (114) in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) coating a set of reinforcement fibres in the dispersion, thereby obtaining a set of coated reinforcement fibres; c) pre-heating the set of coated reinforcement fibres; d) passing a length of the coated reinforcement fibres over an arc of each of a plurality of heated pins (212a, 212b, 212c), wherein each of the plurality of heated pins is heated to a polymer-impregnation temperature, thereby obtaining a length of polymer-impregnated reinforcement fibres; and e) cooling the length of polymer-impregnated reinforcement fibres to obtain a length of fibre-reinforced composite tape. The polymer-impregnation temperature is greater than or equal to a melting point of the first thermoplastic.

Description

[0001] A Method of Producing a Fibre-Reinforced Composite

[0002] Technical field

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

[0004] Background

[0005] Over the last few decades, the so-called advanced reinforced thermoplastic materials, based on composite materials having fibres embedded in a thermoplastic polymer, have been increasingly used in several industries, such as aerospace, automotive, general manufacturing, chemical, oil and gas, medical, sport and leisure. One of the main drivers for the use of composites is weight reduction. Their high strength and stiffness at low weight allows composites to partly or fully replace metals for many applications. Such composite materials can provide good performance and controlled properties through high fibre volume fractions and well-defined fibre alignment within the composite. The reinforcement fibres may be unidirectional or woven, for example, wherein the polymeric / thermoplastic bonds the reinforcement fibres together during manufacture.

[0006] Advanced reinforced thermoplastic materials may be used in the form of tapes, in which reinforcing fibres are embedded in a thermoplastic matrix polymer. The manufacture of tapes is described in, for instance, US Patent 4,626,306 where an aqueous dispersion impregnation method is set out. Such tapes may be used to manufacture composite articles by using processes in which the tapes are formed and consolidated / laminated together, typically subjected to heat to make the thermoplastic polymer malleable, and / or pressure to shape the component, followed by a cooling step to return the thermoplastic polymer to a solidified state.

[0007] Fibre-reinforced composite materials are generally manufactured by first coating reinforcement fibres with a polymeric dispersion, which is subsequently melted to impregnate the fibres with the thermoplastic comprised in the dispersion. The polymeric / thermoplastic dispersion is usually provided as a suspension or dispersion of particles in a liquid.

[0008] The fibres themselves contain a large number of fibre filaments. To obtain fibre-reinforced composites of a desired quality, e.g., resilient and / or strong and / or having the desired properties to be consolidated together, and / or good interlaminate shear strength, good impregnation between all fibres with the thermoplastic material is desirable. It can be difficult to impart uniform and consistent impregnation into a set of fibres, particularly when the volume or sheer number of fibres filaments provides obstruction or resistance to being impregnated.

[0009] Furthermore, in addition to good impregnation of thermoplastic into the composites, it is desirable to be able to impart a particular quality onto the surface of the fibre-reinforced composites. The particular property and / or quality of the surface of fibre-reinforced composites can be advantageous depending on the application and / or industry where the fibre-reinforced composites is to be used.

[0010] It is, therefore, an object of the present invention to seek to alleviate the above-identified problems. 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.

[0011] Summary of the Invention

[0012] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description.

[0013] In a first aspect there is provided a method of producing a fibre-reinforced composite tape comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) coating a set of reinforcement fibres in the dispersion, thereby obtaining a set of coated reinforcement fibres; c) pre-heating the set of coated reinforcement fibres; d) passing a length of the coated reinforcement fibres over an arc of each of a plurality of heated pins, wherein each of the plurality of heated pins is heated to a polymer-impregnation temperature, thereby obtaining a length of polymer-impregnated reinforcement fibres; and e) cooling the length of polymer-impregnated reinforcement fibres to obtain a length of fibre- reinforced composite tape, wherein the polymer-impregnation temperature is greater than or equal to a melting point of the first thermoplastic.

[0014] In a second aspect there is provided a method for producing a fibre-reinforced composite having a smooth and / or glossy surface, comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) coating a set of reinforcement fibres in the dispersion, thereby obtaining a set of coated reinforcement fibres; c) pre-heating the set of coated reinforcement fibres; d) passing a length of the coated reinforcement fibres over an arc each of a plurality of heated pins, wherein each heated pin of the plurality of heated pins is heated to a polymer- impregnation temperature, thereby obtaining a length of polymer-impregnated reinforcement fibres; and e) cooling the length of polymer-impregnated reinforcement fibres thereby consolidating the fibres to obtain a length of fibre-reinforced composite tape, wherein each heated pin of the plurality of heated pins rotates, in step d), with respect to a movement of the coated reinforcement fibres, and wherein the polymer-impregnation temperature is equal to or greater than a melting point of the first thermoplastic.

[0015] In a third aspect there is provided a method for producing a fibre-reinforced composite having a roughened surface, comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) coating a set of reinforcement fibres in the dispersion, thereby obtaining a set of coated reinforcement fibres; c) pre-heating the set of coated reinforcement fibres; d) passing a length of the coated reinforcement fibres over an arc of each of a plurality of heated pins, wherein each of the plurality of heated pins is heated to a polymer-impregnation temperature, thereby obtaining a length of polymer-impregnated reinforcement fibres; and e) cooling the length of polymer-impregnated reinforcement fibres thereby consolidating the fibres to obtain a length of fibre-reinforced composite tape, wherein the plurality of heated pins are static with respect to a movement of the coated reinforcement fibres, and wherein the polymer-impregnation temperature is equal to or greater than a melting point of the first thermoplastic.

[0016] In a fourth aspect there is provided a fibre-reinforced composite tape produced according to a method of any of the first, second or third aspects.

[0017] In a fifth aspect there is provided a fibre-reinforced composite tape manufacturing apparatus comprising: a) a container arranged to contain a dispersion comprising water and particles of a polymeric composition comprising a first thermoplastic; b) a heating device configured to pre-heat a set of coated reinforcement fibres; c) a plurality of heated pins, each of which is configured to allow a length of coated reinforcement fibres to pass over an arc of said heated pin; and d) a cooling zone configured to cool a length of length of polymer-impregnated reinforcement fibres; wherein each heated pin of the plurality of heated pins is configured to be heated to a polymer- impregnation temperature being greater than or equal to a melting point of the first thermoplastic.

[0018] Brief Description of the Figures

[0019] The present disclosure will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 illustrates a side-profile view of the first part of an apparatus for producing a fibre-reinforced composite, where the fibre storage, coating, and pre-heating stages of the apparatus are shown;

[0020] Figure 2 illustrates a side-profile view of the second part of an apparatus for producing a fibre-reinforced composite, where polymer-impregnation and cooling stages of the apparatus are shown;

[0021] Figure 3a illustrates a side-profile view of an example polymer-impregnation stage having three pins; and

[0022] Figure 3b illustrates a side-profile view of an example polymer-impregnation stage having five pins.

[0023] 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.

[0024] Detailed Description

[0025] In a first aspect there is provided a method of producing a fibre-reinforced composite tape comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) coating a set of reinforcement fibres in the dispersion, thereby obtaining a set of coated reinforcement fibres; c) pre-heating the set of coated reinforcement fibres; d) passing a length of the coated reinforcement fibres over an arc of each of a plurality of heated pins, wherein each of the plurality of heated pins is heated to a polymer-impregnation temperature, thereby obtaining a length of polymer-impregnated reinforcement fibres; and e) cooling the length of polymer-impregnated reinforcement fibres to obtain a length of fibre- reinforced composite tape, wherein the polymer-impregnation temperature is greater than or equal to a melting point of the first thermoplastic.

[0026] Heating the plurality of heated pins to a polymer-impregnation temperature causes particles of the polymeric composition to at least partially melt, such that passing the set of fibres over the plurality of heated pins causes the polymer to become impregnated with the fibres, e.g., by mechanical force that urges the polymer to impregnate the fibres. This action of the heated pins results in an advantageously uniform polymer matrix becoming interspersed within the fibres, with advantageously few voids, preferably no voids. Preferably, the cooling step consolidates and / or sets the polymer-impregnated reinforcement fibres such that the polymer-impregnated fibres form a length of fibre-reinforced composite tape whose dimensions are fixed. Preferably, the plurality of heated pins is heated to at least the melting temperature of the first thermoplastic such that the polymeric composition, once molten, is mobile. The mobile polymer composition thus can freely move in between fibres, for example, in between microscopic and even nanoscopic gaps in between the fibres. The heat provided by the plurality of heated pins preferably transfers the thickness of the set of reinforcement fibres such that substantially the mobile polymer can reach all interstitial areas, such that substantially no voids remain.

[0027] Preferably, during step d), the plurality of heated pins melt at least some of the particles of a polymeric composition to form a molten polymeric composition and urge a portion of the molten polymeric composition in between the reinforcement fibres to thereby obtain the length of polymer-impregnated reinforcement fibres.

[0028] The action of passing the length of the coated reinforcement fibres over the plurality of heated pins urges, by mechanical force, the molten polymer in between the reinforcement fibres. Thus, the polymeric composition, once cooled, does not merely consolidate the fibres together by coating a surface of the fibres but becomes uniformly interspersed in between the fibres. Thus, the resulting fibre- reinforced composite tape is advantageously robust and comprises an evenly distributed polymer matrix. In other words, the improved impregnation of the polymer in between the interstitial gaps of the fibres results in a continuous network of polymer that is reinforced by uniformly spaced fibres. The improved impregnation thus results in minimal voids in the resulting length of fibre-reinforced composite tape. This has the advantage of enabling substantially void-free laminates and structures to be manufactured.

[0029] Preferably, pre-heating the set of coated reinforcement fibres comprises subjecting the set of coated reinforcement fibres to a temperature of at least about 20 Celsius below the melting point of the first thermoplastic, preferably about 10 Celsius below the melting point of the first thermoplastic, preferably about a melting point of the first thermoplastic, more preferably to about the polymer-impregnation temperature.

[0030] Preferably, the pre-heating comprises passing the set of coated reinforcement fibres through one or more ovens. Preferably, subjecting the set of coated reinforcement fibres to the polymer-impregnation temperature causes at least some of the polymer to melt prior to step (d). It is advantageous to melt the polymer, at least partially, prior to passing the coated set of fibres over the plurality of heated pins to ensure that the polymer is already partially molten and mobile at the point that the fibres contact the first pin. This results in the best impregnation since it increases the duration of time over which mobile polymer can be mechanically urged in between the fibres. In other words, the polymer composition is mobile and can be urged to intersperse within filaments of the set of fibres for substantially all of the time that the fibres are passed over and contact each respective arc of the plurality of heated pins.

[0031] It should be nevertheless appreciated that, although subjected to the polymer-impregnation temperature, the fibres themselves in the set of reinforcement fibres may not actually become heated to the polymer-impregnation temperature during the pre-heating. In some examples, the coated set of set of reinforcement fibres may be heated to just under the melting point of the first thermoplastic during the pre-heating stage.

[0032] Preferably, step c) comprises removing water from the coated reinforcement fibres, preferably drying the coated reinforcement fibres, preferably prior to drying, wherein after step b) and prior to step c) the coated fibres comprise less than 20 wt% water, preferably less than 10 wt% water, preferably less than 5% water. Preferably, substantially all of the water, or all of the water, is removed from the coated reinforcement fibres during the pre-heating stage. The removal of water occurs primarily by evaporation, though some excess water may simply fall way under gravity. The fibres may swell after having been coated by the dispersion as a result of absorbing water. Therefore, substantially drying the coated fibres advantageously results in fibres that are free of water such that they can be arranged, prior to passing over the plurality of heated pins pin in step d), in a structure / configuration of the desired composite tape. Removing substantially all water also helps avoids voids from forming in the resulting fibre-reinforced composite tape.

[0033] Preferably, a surface of each of the first and second heated pins has a temperature between about 5 to about 70 Celsius, for example about 5 to about 50 Celsius, above the melting point of the first thermoplastic. This ensures that substantially all, or all, of the particles of the polymer composition have melted, or remain molten. This has the advantage of ensuring that the molten polymer is sufficiently mobile, thus improving the impregnation and dispersion of molten polymer amongst the fibres during the polymer-impregnation step d).

[0034] Preferably, a surface of each of the plurality of heated pins has a temperature between about 280 Celsius and 380 degrees Celsius, preferably between about 300 Celsius and 360 degrees Celsius. Preferably the melting point of the first thermoplastic is about 303 Celsius or about 343 Celsius.

[0035] For example, when the first thermoplastic of the polymer composition comprises PEEK having a melting point of about 343 Celsius, the temperature of the heated pins may be in the range of about 350 to about 380 Celsius. In another example, when the first thermoplastic of the polymer composition comprises a copolymer of PEEK and polyetherdiphenyletherketone (PEDEK), having a melting point of about 303 Celsius, the temperature of the heated pins may be in the range of about 340 to about 360 Celsius

[0036] Preferably, the cooling in step e) comprises passing the length of polymer-impregnated reinforcement fibres through one or more cooling apparatus.

[0037] Preferably, the method further comprises maintaining a temperature of the polymer-impregnated reinforcement fibres to at least a melting point of the first thermoplastic until at least the length of polymer impregnated fibres reaches a consolidation area. It is advantageous for the polymer composition to be molten at the point that the fibres reach the consolidation area, such that the length of polymer- impregnated fibres are consolidated having the structure and configuration that is imparted by the heated pins. Since the heated pins improve the impregnation and interspersion of polymer into the fibres, it is beneficial to maintain these impregnation conditions by consolidating, e.g., cooling below melting point, the polymer shortly after the fibres have left the rollers. Preferably, the consolidation area cools the polymer-impregnated fibres to below the melting point of the first thermoplastic so as to cure / set the structure / distribution of the polymer within the fibres.

[0038] Preferably, each of the plurality of heated pins are separated along a direction of travel of the length of the coated reinforcement fibres, and wherein step d) comprises: passing a first surface of the length of coated reinforcement fibres over an arc of a first heated pin, and passing a second surface of the length of coated reinforcement fibres, opposing the first surface, over an arc of a second heated pin.

[0039] The lateral separation of the heated pins along a direction of travel of the length of the coated reinforcement fibres may be in the range of about 10 cm to about 100 cm, preferably about 15 cm to about 50 cm. Passing opposing sides of the length of coated reinforcement fibres over two heated pins ensures that the polymer is mechanically impregnated on both sides of the length of coated reinforcement fibres such that the consolidated composite has substantially the same, or the same, surface properties on both sides of the tape. Moreover, passing the length of coated reinforcement fibres over both sides of the fibres results in even heat distribution, thereby ensuring improved impregnation from both sides of the length of coated reinforcement fibres.

[0040] Preferably, the fibres of the set of reinforcement fibres are tensioned during at least step d), preferably tensioned during each of steps b), c), d), preferably also tensioned during step e). The tension imparts a normal force between the length of coated fibres and each of the plurality of heated pins. The normal force thereby mechanically urges the molten polymer in between the fibres to obtain a robust consolidated composite tape having an even distribution of polymer, preferably without voids. A normal force should be understood as a force whose direction is perpendicular or substantially perpendicular to a tangent to the surface of the length of reinforcement fibres (or, equally, perpendicular to a tangent to the surface of the arc of a heated pin).

[0041] Preferably, pre-heating the set of coated reinforcement fibres comprises passing at least a portion of the set of coated reinforcement fibres through at least one heating oven. Preferably, heating the set of coated reinforcement fibres comprises heating the fibres to at least the polymer-impregnation temperature thereby melting at least some of the particles of a polymeric composition to form a molten polymeric composition.

[0042] Preferably, an insulating heat shield is disposed immediately before a position of a first heated pin of the plurality of heated pins along a direction of travel of the coated set of reinforcement fibres. In other words, an insulating heat shield is disposed between an exit of the at least one heating oven and a first heated pin of the plurality of heated pins, wherein the pre-heating comprises passing the length of coated reinforcement fibres past, e.g., underneath, the insulating heat shield.

[0043] Preferably, the heat shield is disposed across substantially all of the gap between the exit of the at least one heating oven and the first heated pin, thus reducing heat loss in the pre-heated length of coated reinforcement fibres, preferably such that the temperature of the length of coated reinforcement fibres remains at least above the polymer-impregnation temperature. It is advantageous if the polymer is still molten at the point where the coated fibres contact the first heated pin such that the polymer is mobile and thus can immediately be urged to impregnate in between the fibres. Without the heat shield, i.e., in open air, heat loss can be great therefore the shield provides an energy-efficient way to maintain the temperature and / or molten state of the polymer immediately prior to contacting the heated pins.

[0044] Preferably, the insulating heat shield is comprised of ceramic. Preferably the heat shield is disposed as a plate above the path taken by the tape, so as to allow venting for volatile organics such as diphenyl sulfone (DPS).

[0045] Preferably, step c) comprises passing alternately opposing sides of the length of the coated reinforcement fibres over successive heated pins of the plurality of heated pins. By passing alternately opposing sides of the length of the coated reinforcement fibres over successive heated pins, it is ensured that the polymer is impregnated into fibres on both sides of the length of coated reinforcement fibres, i.e., such that the composite has substantially the same, or the same, surface properties on both sides of the tape. In other words, passing alternating sides / faces of the set the coated reinforcement fibres over the heated pins ensures that the mechanical force which urges the polymer to impregnate all fibres is equal, or substantially equal, on both sides of the polymer. This has the advantage of producing a composite tape where both sides of the tape have the same, or substantially the same, propensity to be laminated together, thereby forming structurally robust layers with good interlaminate shear strength.

[0046] Preferably, the plurality of heated pins comprises at least three heated pins, or at least four heated pins, or at least five heated pins.

[0047] Preferably, in one embodiment, each heated pin of the plurality of heated pins is configured to rotate in a direction that, when the length of the coated reinforcement fibres is passed over each respective arc of each respective heated pin, matches a direction of travel of the length of the coated reinforcement fibres.

[0048] In other words, the first and second heated pins rotate with respect to a movement of the coated reinforcement fibres. The rotation may be idle, i.e., driven by the movement of the fibres and urged to rotate by the movement of the fibres, which may be tensioned to further encourage rotation which matches a speed of travel of the fibres. Alternatively, heated pins may be motorised to rotate to match the speed of travel of the fibres. In some examples, the heated pins may be motorised to rotate in a direction that matches the direction of travel of the fibres, but at a speed that is faster or slower than a speed of travel of the fibres. In examples where successively adjacent heated pins are arranged to contact alternate surfaces of the coated reinforcement fibres, the direction of rotation of the heated pins will alternate from clockwise to anti-clockwise to match the direction of travel of the fibres. For example, where three pins are used, the direction of rotation of the three heated pins may be: clockwise; anticlockwise; and clockwise. Rotating the pins to match a movement of the length of the coated reinforcement fibres produces a glossy / smooth surface on the resulting composite tape. This has the advantage that composite tapes with glossy surfaces can be laminated together to produce structures with improved strength, for example, specifically having improved interlaminate shear strength. In some examples, this is because composite tapes produced using rotating pins have a higher fraction of polymer in the resulting composite tape which yields stronger interlaminate welds.

[0049] Preferably, in another embodiment, each heated pin of the plurality of heated pins is stationary. Statis / stationary pins create a rougher surface which is advantageous for some applications, for example tape for use in medical applications.

[0050] Preferably, a temperature of the final heated pin of the plurality of heated pins, over which the length of the coated reinforcement fibres passes, is at least about 10 Celsius to about 80 Celsius above the melting point of the first thermoplastic, preferably at least about 25 Celsius to about 50 Celsius above the melting point of the first thermoplastic, more preferably about 40 to about 50 Celsius above the melting point of the first thermoplastic. Preferably, the temperature of the final heated pin of the plurality of heated pins, over which the length of the coated reinforcement fibres passes, is in the range of about 320 Celsius to about 400 Celsius, for example 320 to 380 Celsius, for example 340 to 390 Celsius.

[0051] It is beneficial for the polymer in the polymer-impregnated fibres to remain molten until the fibres reach the cooling stage (at which point the polymer is cured into a desirable configuration / dimension). Consequently, it is advantageous to set the temperature of the final heated pin as disclosed to ensure that, even accounting for some heat loss, the polymer remains molten for the desired amount of time after contact with the final heated pin. In more detail, preferably at least some, and preferably all, of the polymer composition on the length of polymer-impregnated fibres is in a molten state immediately after said length of fibres passes over the final heated pin. It is desirable to set the polymer of the polymer- impregnated tape quickly, i.e., in under 2 seconds, preferably in under 1 second, so as to maintain the state in the polymer matrix that has been imparted by the heated pins. The cooling step causes the polymer to set, e.g., set, to form a consolidated composite tape, preferably by rollers. Consequently, in order to ensure that the polymer is still molten at the point it is cooled, it is advantageous to heat the heated pin above the melting point of the thermoplastics, i.e., by a buffer of at least about 10 Celsius to about 60 Celsius. This ensures that even as the polymer cools after the tape has passed over the final heated pin, the polymer does not solidify immediately or prior to reaching the cooling stage. Preferably, at least some of the plurality of heated pins are heated by providing at least one heat cartridge within an internal cavity of each of the heated pins. This has the advantage that the heat cartridges can be positioned precisely in the area where heat needs to be applied, e.g., substantially co-located with an area over which the length of the coated reinforcement fibres passes.

[0052] Preferably, the set of reinforcement fibres comprises non-metal fibres including fibres selected from the group of glass fibres, carbon fibres, preferably unidirectional carbon fibres, aramid fibres, Ultra-High Molecular Weight Polyethylene (UHMwPE) fibres, basalt fibres, and combinations thereof, preferably carbon fibres.

[0053] Preferably, the first thermoplastic is selected from a group comprising the following polyaryletherketone (PAEK), 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 or combination thereof.

[0054] Preferably, each heated pin of the plurality of heated pins is substantially cylindrical, preferably wherein, in step d): a longitudinal axis of each heated pin is substantially perpendicular to a direction of travel of the set of coated reinforcement fibres, and substantially parallel with a plane of the set of coated reinforcement fibres. Consequently, a surface area of contact between the length of the coated reinforcement fibres and the arc of the heated pins is increased and / or maximised, and the normal force that urges the molten polymer composition to impregnate in between the fibres is increased and / or maximised.

[0055] Preferably, a diameter of each heated pin of the plurality of heated pins is about 2 cm to about 15 cm, preferably less than 10cm, more preferably about 6 cm to about 8 cm, most preferably 7cm.

[0056] Preferably, a width of the length of fibre-reinforced composite tape is in the range of about 1 cm to about 70 cm, preferably in the range of about 1 .5 cm to about 25 cm, and wherein a thickness of the length of fibre-reinforced composite tape is in the range of about 0.1 mm to 0.4mm, for example 0.3mm.

[0057] Preferably, a thickness and / or diameter of filaments of fibres of the set of reinforcement fibres is in the range of about 2 pm to about 20 pm, preferably about 4 pm to about 15 pm, more preferably about 4 pm to about 8 pm.

[0058] Preferably, the set of reinforcement fibres comprises non-metal fibres including fibres selected from the group of glass fibres, carbon fibres, aramid fibres, UHMwPE fibres, basalt fibres, and combinations thereof, preferably carbon fibres. The set of reinforcement fibres may comprise fibres selected from any of the groups of fibres described above and / or mixtures thereof. Preferably, the PEEK polymer has a repeat unit of formula I:

[0059] -O-Ph-O-Ph-CO-Ph- I wherein Ph represents a phenylene moiety. In this embodiment, all phenylenes are 1 ,3- and / or 1 ,4- substituted to the adjacent ether and / or carbonyl groups.

[0060] Preferably, the PEDEK polymer has a repeat unit of formula II

[0061] -O-Ph-Ph-O-Ph-CO-Ph- II wherein Ph represents a phenylene moiety and wherein the repeat units I and II are in the relative molar properties l:ll of from 65:35 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.

[0062] In a second aspect, there is provided a method for producing a fibre-reinforced composite having a smooth and / or glossy surface, comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) coating a set of reinforcement fibres in the dispersion, thereby obtaining a set of coated reinforcement fibres; c) pre-heating the set of coated reinforcement fibres; d) passing a length of the coated reinforcement fibres over an arc each of a plurality of heated pins, wherein each heated pin of the plurality of heated pins is heated to a polymer- impregnation temperature, thereby obtaining a length of polymer-impregnated reinforcement fibres; and e) cooling the length of polymer-impregnated reinforcement fibres thereby consolidating the fibres to obtain a length of fibre-reinforced composite tape, wherein each heated pin of the plurality of heated pins rotates, in step d), with respect to a movement of the coated reinforcement fibres, and wherein the polymer-impregnation temperature is equal to or greater than a melting point of the first thermoplastic.

[0063] The advantages of providing a glossy and / or smooth surface are described above in this specification, and exemplified in the following detailed description.

[0064] In a third aspect, there is provided a method for producing a fibre-reinforced composite having a roughened surface, comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) coating a set of reinforcement fibres in the dispersion, thereby obtaining a set of coated reinforcement fibres; c) pre-heating the set of coated reinforcement fibres; d) passing a length of the coated reinforcement fibres over an arc of each of a plurality of heated pins, wherein each of the plurality of heated pins is heated to a polymer-impregnation temperature, thereby obtaining a length of polymer-impregnated reinforcement fibres; and e) cooling the length of polymer-impregnated reinforcement fibres thereby consolidating the fibres to obtain a length of fibre-reinforced composite tape, wherein the plurality of heated pins are static with respect to a movement of the coated reinforcement fibres, and wherein the polymer-impregnation temperature is equal to or greater than a melting point of the first thermoplastic.

[0065] The advantages of providing a roughened surface are described above in this specification, and exemplified in the following detailed description.

[0066] In a fourth aspect, there is provided a fibre-reinforced composite tape produced according to any of the first, second, or third aspects.

[0067] In a fifth aspect, there is provided a fibre-reinforced composite tape manufacturing apparatus comprising: a) a container arranged to contain a dispersion comprising water and particles of a polymeric composition comprising a first thermoplastic; b) a heating device configured to pre-heat a set of coated reinforcement fibres; c) a plurality of heated pins, each of which is configured to allow a length of coated reinforcement fibres to pass over an arc of said heated pin; and d) a cooling zone configured to cool a length of length of polymer-impregnated reinforcement fibres; wherein each heated pin of the plurality of heated pins is configured to be heated to a polymer- impregnation temperature being equal to or greater than a melting point of the first thermoplastic.

[0068] In general, fibre-reinforced composite tapes are formed into larger structures and laminates by consolidation using oven and vacuum techniques. However, this precludes larger parts being made, e.g., parts designed for the aerospace industry. Fibre-reinforced composites made according to the present disclosure may be consolidated more robustly than conventional fibre-based composites, which advantageously permits them to be consolidated using out-of-autoclave (OOA) consolidation techniques. As described, this is at least in part due to the fact that composites produced according to presently-disclosed methods have advantageously uniform polymer matrix interspersed between the fibres of the composites. OOA allows larger parts to be manufactured. Further, the improved consolidation properties of the presently-disclosed fibre-reinforced composites can allow significantly faster in-situ layup of the composites using OOA techniques (such as heated tooling), for example by a factor of about 4, 5, or 6. Moreover, thicker structures than are conventionally obtainable may be made by OOA techniques using the presently-disclosed fibre-reinforced composites and methods of producing the same. Figures 1 and 2 illustrate two parts of an apparatus for producing fibre-reinforced composite tape. Thus, figures 1 and 2 illustrate one example of a production line suitable to carry out the methods disclosed herein for producing fibre-reinforced composite tapes. The individual stages will be described in detail. The skilled person will understand that the stages are illustrated and described as separate stages merely for convenience. The compartmentalisation of the stages is arbitrary and is not intended to limit the design of the apparatus. For example, additional stages may be included in between the illustrated stages, and / or some integers contained within the stages may be omitted in various examples, as would be apparent to the skilled person. Moreover, although indicated as a continuous production line in which the tape progresses from one stage to the next, this should not be interpreted as necessary, and the stages may in some examples be physically and temporally separated and thus form two or more individual production workflows.

[0069] Figure 1 illustrates examples of an apparatus for carrying out part of the method described herein. Figure 1 illustrates an unwinding 100 stage, a coating stage 102, and at least part, if not all, of a preheating stage 104. These stages will now be described with example parameters.

[0070] Unwinding stage 100

[0071] A tow of fibre is stored on bobbins 106 on creel. Each tow contains bare fibres that are not chemically bound or interconnected; i.e. no material other than the fibres themselves forms part of the fibre tows. Individual tows 108 are seen being drawn from the bobbins 106.

[0072] Several tows 108 of fibre from respective bobbins 106 are led towards a gathering point. For example, the fibres may be led through an eyelet, or other suitable device. Bars 110 illustrated are aimed at preventing the fibres from twisting out of shape, and as such may be called anti-twist bars 110. Since the fibres are stored wound up, once unwound they have a propensity to twist away from a linear configuration. Therefore, although optional, the anti-twist bars 110 have the advantage of helping to gather the tows into a substantially flat arrangement. After having passed through the anti-twist bars, the tows of fibres are gathered together in a flat or substantially flat / planar arrangement that resembles a tape.

[0073] The width of the tape 112 is dependent on the number of tows of fibres, and the number of filaments per tow. The number of tows may be, for example, between about 4 to about 140, preferably, between about 4 to about 50.

[0074] Coating stage 102

[0075] The tows of fibres, once gathered, form a tape structure 112. Gaps, including visible gaps, may exist along the length of the fibres and / or between the tows, which is normal and not problematic at this stage. The set of fibres 112 is then led into a container 114 filled with a dispersion (not shown) such that the gathered fibres 112 become immersed / submerged in the dispersion. The dispersion comprises a polymeric composition comprising a first thermoplastic in a liquid comprising water, thereby forming the dispersion. The particles are suspended in the liquid dispersion, i.e. not dissolved. Thus, the dispersion comprises and / or is a suspension of the particles in the liquid. The details of example compositions and parameters of the dispersion are described below in more detail. Generally, the dispersion liquid comprises water in a range from about 60 wt.% to about 100 wt.%, preferably in the range of about 80 wt.% to about 100 wt.%, preferably in a range from about 85 wt.% to about 99 wt.%, by weight of the liquid. The liquid may also comprise amounts of organic solvent and / or surfactant to assist with dispersing the particles of the polymer composition. Some of the particles of the polymer composition have low surface energy, and thus are difficult to disperse in water, and are prone to settling. 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. Generally, the container also contains a mixing device to disturb / mix the particles in the dispersion. It is desirable to evenly coat the gathered fibres 112 with the particles, which can be performed by evenly dispersing particles to obtain a homogenous dispersion. The mixing device helps to achieve this homogenous dispersion and thus promotes an even coating of polymer particles.

[0076] Once the fibres exit the container and dispersion, at least the surface of the fibres becomes coated in the dispersion. An excess of water may initially be deposited on the surface, which may be removed simply by passing the coated fibres, preferably under tension, over a set of fixed bars 118. The tension is provided along a direction of travel of the fibres, i.e., in a longitudinal direction along the length of the fibres. In some examples, a set of rollers may be used instead of, or in addition to, the fixed bars to further remove the excess water. The excess water is preferably directed back into the container 114 to re-enter the dispersion.

[0077] The fibres generally swell with water after moving through the dispersion, meaning that at least some of the excess water may remain within the fibres after passing through the fixed bars. The excess water may temporarily disrupt the arrangement of fibres and / or produce gaps, but this is not problematic.

[0078] Pre-heating stage 104

[0079] After passing through the dispersion, the fibres are directed through at least one heating area to dry and / or pre-heat the fibres. Preferably, the heating areas comprise at least one oven each having at least one heating zone.

[0080] The pre-heating stage is aimed at drying the water from the fibres, such that no or substantially no water remains in the fibres when the set of fibres reaches the polymer-impregnation stage (i.e., the stage at which the polymer is heated to its melting point so as to impregnate the fibres). Another function of the pre-heating stage is to raise the temperature of the particles of the polymer composition and / or the fibres such that the polymer composition is near to its melting point (or, at or near a melting point of at least one thermoplastic within the polymer composition) once the pre-heating stage has finished. In this way, the polymer can be immediately or very quickly melted when the polymer-impregnation stage 200 commences. In other examples, the melting point of at least one thermoplastic within the polymer composition may be reached during the pre-heating stage. Some degree of impregnation of molten or semi-molten polymer into the fibres may therefore occur during the pre-heating stage 104.

[0081] The fibres that enter the pre-heating stage are coated fibres 120, which have preferably had excess water removed. The ovens 122, 124 shown in the figures are not to scale.

[0082] The first oven 122 comprises an enclosed section, preferably open at both ends. Preferably, the air temperature of the oven 122 is sufficient to dry or substantially dry the water from the fibres. The air temperature is preferably within about 150 Celsius, preferably 100 Celsius (above or below) of the melting point of the polymer composition coated on the fibres, more preferably within about 50 Celsius. For example, the air temperature of the oven may be about 20 Celsius to about 50 Celsius higher than the melting point of the polymer composition. For example, the air temperature inside the first oven 122 may be about 300 Celsius to about 400 Celsius, preferably about 320 to about 380 Celsius, more preferably about 340 to about 360 Celsius. In examples where the polymer composition contains polyaryletherketone (PAEK) thermoplastics such as polyetheretherketone (PEEK), the oven may heat the air to about 360 degrees Celsius.

[0083] After exiting the dispersion the fibres are preferably at ambient room temperature, e.g., about 15 Celsius to about 30 Celsius. Due to the amount of water contained in the fibres, and / or the albedo of the coating of the polymer composition, the temperature of the fibres themselves may not be raised significantly by the first oven. For example, after exiting the first oven 122, the temperature of the fibres may be about 30 Celsius to about 60 Celsius, preferably about 40 to 50 Celsius. Evaporation of water from the surface of the fibres may remove heat from the fibres.

[0084] The coated fibres 120 likely contract after exiting the first oven 122, due to the removal by evapouration of all or most of the water. The contraction may be visible, e.g., gaps may appear between adjacent tows or fibres. However, this is to be expected during the pre-heating stage and is not problematic.

[0085] The second oven 124 may be the same type, and have substantially the same dimensions, as the first oven 122. Preferably said second oven heat the air to about the same temperature as the first oven. For example, the air temperature of the second oven is preferably within about 100 Celsius (above or below) of the melting point of the polymer composition coated on the fibres the air temperature inside the second oven 124 may be about 300 Celsius to about 400 Celsius, preferably about 320 to about 380 Celsius, more preferably about 340 to about 360 Celsius.

[0086] The first oven 122 substantially or wholly removes water from the fibres. Thus, by the point that the coated set of fibres 120 reaches the entrance of the second oven 124, the fibres heat up much more rapidly, i.e., because they are no longer cooled down by the action of evaporation from the fibres’ surface. Once the set of coated fibres 120 (now substantially or totally dry, i.e., devoid of water) exits the second oven, their temperature is preferably closer to a melting point of the particles of polymer composition, e.g., in the range of about 200 to about 50 Celsius less than a melting point of the polymer composition, more preferably in the range of about 75 to about 125 Celsius less than a melting point of the polymer composition. For example, the temperature of the coated fibres after exiting the second oven 124 may be about 150 to about 250 Celsius, more preferably about 175 to about 225 Celsius, preferably about 200 Celsius. This corresponds to examples where the polymer contains, or is, a PEEK polymer having a melting point in the range of about 300 to about 350 Celsius.

[0087] It will be appreciated by the skilled person that a different number, configuration, or type of ovens or heating apparatuses may be suitable to dry and / or pre-heat the coated fibres prior to the polymer- impregnation step. For example, the two ovens 122, 124 shown may be combined as a single oven, or reduced in length but having increased temperatures.

[0088] Polymer-lmpreqnation stage 200

[0089] Preferably, the particles of polymer composition contained in the coating, having been deposited in the coating stage 102 described above, are substantially dry and in a solid state prior to being impregnated into the fibres. Nevertheless, some of the particles of polymer composition may have melted to form a molten polymer composition for the impregnation step to be most effective. In some examples, the preheating stage may heat the fibres just below the melting point of the polymer composition, or in some cases at or just above the melting point of the polymer composition. In other examples, the particles of polymer composition may be heated to melting point, i.e., from room temperature, entirely during the impregnation stage - in this sense, the pre-heating stage may form part of, and be indistinguishable from, the polymer-impregnation stage.

[0090] Figure 2 illustrates a continuation of the apparatus shown in figure 1 . The impregnation stage 200 is shown, which in this example includes a further heating apparatus 204, an insulating heat shield 208, a guide rail 210, and three heated pins 212a, 212b, and 212c. The heating apparatus 204 is preferably an oven. In the example illustrated in figure 2, the third oven 204 forms part of the impregnation stage because, preferably, the oven 204 preceding the heated pins is configured to melt at least some of the polymer composition on the coated fibres 120.

[0091] However, in other examples, the polymer-impregnation stage 200 may include only the heated pins, and may optionally include the guide rail 210, and may further optionally include the insulating heat shield 208. In such an example, the pre-heating stage 104 shown in figure 1 may provide all of the heating stages. Thus, in some examples, the pre-heating stage contains one, two, three, or possibly more ovens which dry and heat the coated set of fibres 120 to a sufficient degree such that, when the fibres contact the first heated pin 212a of the impregnation stage, the at least some of the polymer composition melts. Continuing with this example (i.e., with no heating element in the impregnation stage 200), the pre-heating stage 104 may partially melt the polymer on the coated fibres, e.g., the temperature of the fibres after exiting the pre-heating stage 104 may be equal to or greater than the melting point of the polymer composition, preferably about 5 Celsius to about 30 Celsius above the melting point of the polymer. For example, the temperature of the fibres after exiting the pre-heating stage 104 may be in the range of about 300 Celsius to about 450 Celsius, for example 360 to 400 Celsius.

[0092] Turning back to the example of figure 2, the oven 204 is provided to prepare the polymer coating on the fibre to be impregnated in between the fibres by the heated pins. Therefore, the oven 204 preferably provides heat that is sufficient to melt at least some of the polymer composition on the coated fibres. After exiting the third oven 204, preferably the temperature of the fibres is equal to or greater than the melting point of the polymer composition, preferably about 5 Celsius to about 40 Celsius above the melting point of the polymer composition.

[0093] The optional guide rail 210 sets the width of the set of fibres. The guide rail 210 preferably has a recess, e.g., an annular recess, which is configured to allow the fibres to pass through. The width of the recess defines the desired width of the fibres. Thus, the walls that define the extent of the recess are configured to urge the set of fibres to be a particular width. The guide rail 210 is beneficial because in some cases the fibres may have visibly contracted (in a lateral direction) after passing through the pre-heating stage 104 and / or the third oven 204 (due to evaporation of held water). Thus, gaps may appear between fibres / tows. Therefore, as the fibres pass through the recess in the guide rail the guide rail causes the fibres to move together and thus remove the gaps. In other words, the guide rail makes the set of coated fibres 120 continuous in a lateral direction, thereby obtaining a uniform thickness of fibres across the fibres’ width. The coated fibres, as they reach the heated pins, therefore have an advantageously uniform traverse thickness profile.

[0094] Preferably, some or all of the polymer on the coated fibres 120 is molten after exiting the oven 204, thus forming a molten polymer composition. It is desirable to maintain the molten state of the molten polymer composition between the fibres exiting the oven 204 and contacting the first heated pin 212a (the first heated pin being pin 300a in figure 3b). This is so that the first heated pin 212a, 300a can effectively impregnate the molten polymer composition into the fibres. For example, if the polymer were not molten when it reached the first heated pin 212a, the first heated pin 212a may not be able to effectively urge the polymer in between the fibres, and the polymer may only be in a molten state during the passing over the second 212b or third 212c heated pins. Thus, an insulating heat shield 208 may be included to reduce heat loss from the fibres and thereby maintain the temperature above the melting point of the polymer and / or maintain the molten state of the molten polymer composition prior to the fibres reaching the first heated pin 212a.

[0095] Preferably, the heat shield is ceramic, though other insulating materials may be used. The heat shield 208 is not actively heated in this example, it is simply configured to mitigate heat loss. Preferably, the insulating heat shield does not entirely surround the tape, i.e., so as to allow gases, such as volatile organic components originating from the tape, to be properly vented. For example, small amounts of diphenyl sulfone (DPS) may be present in the dispersion, which may still be evaporating at the during the polymer impregnation stage 200.

[0096] The impregnation of the polymer into the interstitial gaps between fibres is effected by a plurality of heated pins 212a, 212b, 212c. Preferably, at least some of the polymer comprises a molten polymer composition at the point the fibres reach the first heated pin, to promote good impregnation. Three heated pins are shown in figure 2, but two heated pins are sufficient to obtain good impregnation. In yet a further example, four or five (as shown in figure 3b) heated pins may be used.

[0097] The set of coated fibres passes over an arc of each of the heated pins. The amount of arc indicated in figure 2 is not to scale, and moreover the amount of arc is variable and dependent on factors including the heat of the pins and the melting point of the polymer. For example, the arc over which the fibres pass may be in range of between about a 5 degree arc to a 90 degree arc, preferably in the range of about a 15 degree arc to about a 60 degree arc. As illustrated, the fibres pass over alternating sides of each pin, such that alternate sides / planes of the fibres contact a heated pin. This has the advantage that the heated pins urge the molten polymer composition in between the fibres from both sides of the set of fibres, thereby obtaining an even and uniform impregnation. Moreover, depending on the rotation of the pins, a particular surface characteristic may be imparted by the pins. Therefore, it is beneficial for the set of fibres to contact the heated pins on both opposing sides such that a similar, or the same, surface characteristic is imparted on both sides of the resultant fibre-reinforced composite tape.

[0098] The pins encourage / urge good impregnation of molten polymer into the fibres such that molten polymer becomes interspersed in between substantially all, or all, fibres. This includes fibres that are buried / hidden underneath the surfaces of the set of fibres. The heated pins provide this impregnation by various mechanisms.

[0099] In a first respect, fibres are urged apart from one another in a lateral direction, e.g., the set of fibres may be drawn apart from one another such that more fibres are in contact with the molten polymer. In a second respect, the urging of the fibres onto the arc of the heated pins urges the molten polymer along the length of the fibres. In some examples, excess molten polymer may accumulate at the initial point of contact between the arc of the heated pin and the set of fibres, in effect forming a small reservoir of molten polymer over which the length of the fibres is drawn. Consequently, the contact force resulting from the fibres being drawn over the arc of each heated pin urges the polymer into the thickness of the fibres such that the polymer impregnates between the individual filaments of the fibres. Two or more heated pins are used in succession in order to improve the impregnation.

[0100] The heated pins are heated to at least a melting temperature of a thermoplastic within the polymer composition. This temperature of the heated pins may otherwise be referred to as a polymer- impregnation temperature, i.e., a temperature sufficient to effect the impregnation of (molten) polymer into the fibres. All pins may be heated to about the same temperature, or heated to slightly different temperatures. In particular, the temperature of the first pin is preferably raised enough above the melting point of the polymer composition to encourage a mobile polymer melt. A mobile melt ensures a more thorough impregnation throughout the fibres. For example, the temperature of the first pin may be about 5 Celsius to about 40 Celsius above the melting point of the polymer. The second and third (and fourth, fifth etc) heated pins are preferably also heated to within about this range.

[0101] All heated pins perform the action of urging, by mechanical force / pressure, the molten polymer composition between the fibres. Specifically, the arc of the heated pins over which the fibres pass imparts a normal force on the fibres and the molten polymer, which forces the molten polymer into the fibres. In this regard, it is beneficial to tension the fibres in order to encourage mechanical pressure on the fibres. The tension is preferably provided by a haul-off roller 224 that contacts the (cooled) fibre- reinforced composite tape 228 and thus pulls the entire length of fibres through all stages 100, 102, 104, 200, 204 of the process / apparatus. In other examples, other rollers can impart the tension. In some examples, the frictional forces imparted by the heated pins themselves may impart tension. The skilled person would understand the need to balance the amount of tension so as not to over-tension the fibres. Over-tensioning of fibres can cause the fibres to twist, which can deform the fibres and / or create gaps between tows. Over-tensioning may also break filaments of fibres.

[0102] Preferably, the heated pins are heated by heat cartridges 302 provided in internal cavities. The cartridges 302 are not shown in figure 2, but are indicated in figures 3a and 3b. Preferably, a single heat cartridge 302 is provided when a single composite tape is being formed. In some examples, however, multiple sets of fibres may be simultaneously pulled through each stage to produce a respective multiple set of fibre-reinforced composite tapes. In such examples, multiple heat cartridges may be included to align with each of the sets of fibres. For example, two heat cartridges may be used per heated pin where two sets of reinforcement fibres are simultaneously drawn through the apparatus.

[0103] The heated pins may alternatively be heated by an external heat transfer arrangement, for example, using a hot oil system.

[0104] Advantageously, an odd number of heated pins still imparts uniform polymer impregnation, in spite of the fact that one side of the set of fibres will receive more contact with the heated pins than the other. For example, the example in figure 2 shows that the lower side of the set of fibres contacts two heated pins 212a, 212c, and the upper side of the fibres only contacts one heated pin 212b. Uniform polymer impregnation is achieved by virtue of the relative thickness of the set of fibres (e.g., the set of fibres is preferably less than about 1 mm), such that the heat transfer imparted by the heated pins is sufficient to reach the whole thickness of the fibres. Moreover, it can be convenient to use an odd number of pins because this allows that the orientation of the set of fibres may be kept exactly horizontal on either side of the plurality of heated pins. In other cases, for example where thicker sets of fibres are used to produce thicker composite tapes, an even number of heated pins may be used, e.g., two or four pins. Consequently, the plurality of heated pins imparts a more even heat distribution since heat is transferred equally from both sides of the set of fibres.

[0105] Once the set of fibres has passed over each of the plurality of heated pins 212a, 212b, 212c, a set of polymer-impregnated fibres 226 is formed. It is desirable to set / cure the molten polymer in the impregnated fibres 226 immediately, or as soon as practical, such as in under 2 seconds, preferably in under 1 second. Fast forming has the benefit of ensuring that the impregnated molten polymer that has been uniformly interspersed between the fibres is provided in a uniform arrangement before the molten polymer changes its arrangement. The forming of the polymer is performed during the cooling stage 202, preferably by a cooling apparatus that urges or maintains the polymer-impregnated fibres 226 into a desirable configuration or dimension. Thus, it is desirable the keep the polymer molten inside the polymer-impregnated fibres 226 until the fibres 226 reach the relevant cooling apparatus within the cooling stage 202. For this reason, it is preferred to heat the final heated pin, in this case heated pin 212c, to a temperature sufficient to keep the polymer molten. For example, the final heated pin 212c (pin 300b and 212e in figures 3a and 3b, respectively) may be heated to between about 10 Celsius to about 60 Celsius above the melting point of the polymer. Thus, the temperature of the heated pin may be, for example, about 320 Celsius to about 380 Celsius, preferably about 330 Celsius to 360 Celsius. The temperature of the final heated pin is selected so that, once the set of polymer-impregnated fibres 226 reaches the cooling apparatus within the cooling stage 202, the polymer within the fibres 226 is still molten. As mentioned, the distance between the final heated pin and the first rollers 214 can be chosen (e.g., reduced to under about 2 m, preferably under about 1 m, or less) to help ensure this.

[0106] Figures 3a and 3b illustrate further example configurations of heated pins and first rollers 214 and second rollers. The example in figure 3a includes heated pins 300a, 300b, and 300c where the internal heat cartridge 302 that provides heat to the pins is shown. Figure 3b illustrates an example with five heated pins 212a, 212b, 212c, 212d, 212e, again with internal heat cartridges 302. The distance 304 between the final heated pin 212e (in this case, the fifth of five heated pins) and the entrance to the first rollers 214 is shown.

[0107] Generally, based on the considerations described above, the temperature of the heated pins may be chosen depending on various factors to ensure good polymer melt mobility during the passing over the heated pins, and to ensure that the polymer is molten when it reaches the cooling stage. These factors include but are not limited to: a thickness of the fibres, a width of the fibres, the melting point of the polymer, the temperature-dependent viscosity / mobility of the molten form of the polymer, the insulating efficacy of the heat shield 208, the distance between the heat shield 208 and the first heated pin 212a, the distance 304 between the final heated pin 212 and the cooling stage (e.g., the first roller 214), the speed of travel of the fibres, and other factors that would occur to the skilled person. Cooling stage 202

[0108] The polymer-impregnated fibres are cooled in the cooling stage 202, preferably by one or more cooling apparatus. The objective of the cooling stage is primarily to cool the molten polymer in the polymer- impregnated fibres 226 to as to form a fibre-reinforced composite tape 228. The cooling stage therefore cools the polymer-impregnated fibres to below the melting point of the polymer composition. Preferably, the cooling stage cools the polymer-impregnated fibres 226 by a sufficient amount to allow further processing and / or storage of the composite tape 228. Thus, some embodiments of the cooling stage 202 cool the fibres 226 towards room temperature, e.g., to below about 100 Celsius, preferably below about 80 Celsius, more preferably below about 50 Celsius.

[0109] The cooling stage 202 of figure 2 shows three cooling apparatuses: a first roller 214, a second roller 216, and an air knife 218. The air knife 218 provides a jet or stream of air that further cools the polymer of the fibres, preferably to below about 90 Celsius.

[0110] It will be appreciated that all of the apparatus shown in the cooling stage 202 are optional. For example, the cooling stage may simply involve passing the polymer-impregnated fibres through ambient air and / or air-condition (cooled) air so as to create the form ofthe molten polymer to below the melting point of the polymer composition. For example, some polymer compositions may rapidly cool after leaving the final heated pin 212c. In such examples, the cooling stage may simply passively cool the polymer- impregnate fibres to form the fibre-reinforced composite tape 228.

[0111] Nevertheless, the first rollers 214 are preferably used to help define a particular width and thickness in the composite tape. Additionally, the second rollers help aid the rapid forming of the polymer, which has the benefit of ensuring that the uniform impregnation of polymer imparted by the heated rollers remains in the resulting composite tape The first and / or the second roller may have a patterned surface.

[0112] In examples, preferably, the first roller does not remove any edge or extremity from the polymer- impregnated fibres 226, but rather urges the fibres (which are preferably mobile due to the fact that the polymer contained within them is still molten and thus mobile) to form a tape-like structure of a desired width.. The consolidation rollers provide effective cooling, i.e., which sets the composite tape into a desired configuration having a uniformly interspersed polymer matrix. The first rollers 214 preferably set the molten polymer contained within the fibre-impregnated fibres 226, such that the polymer- impregnated fibres leave said rollers with a fixed width that is maintained by the solidified polymer. The first rollers 214 may also be disposed a fixed distance apart to define the thickness ofthe resulting fibre- reinforced composite tape 228.

[0113] The first rollers are preferably made of metal. In some examples, the rollers may passively cool the polymer-impregnated fibres 226 that pass between them. The rollers 214 may thus act as a heat sink. Preferably, said rollers are actively cooled to maintain a particular temperature, and to improve and / or control the cooling provided to the polymer-impregnated fibres. For example, the first rollers (and the surface thereof) may be water-cooled to a temperature of less than about 120 Celsius, preferably less than 100 Celsius, and most preferably to about 70 Celsius. The water that provides the cooling may be significantly cooler, for example, less than about 30 Celsius, or less than about 20 Celsius, preferably about 10 Celsius.

[0114] The second rollers 216 may also be passively cooled or actively water-cooled in the same manner as the first rollers 214. Both pairs of rollers 214, 216 may even share the same water-cooling loop. The second rollers 216 are configured to impart further cooling to the polymer-impregnated fibres, and optionally to help define / urge the polymer-impregnated fibres to have a particular thickness. Optionally, there may be an annealing section (not shown) between the first rollers 214 and the second rollers. The annealing section may provide an insulating environment that allows the polymer-impregnated fibres to cool more gradually, e.g., to avoid defects and / or to impart a desired crystallinity.

[0115] The optional air knife 218 provides a jet or stream of air to impart further cooling for the fibres. The air stream may be room temperature air, or may be actively cooled to below room temperature. The temperature of the polymer-impregnated fibres after exiting the second rollers 218 may be in the range of about 70 Celsius to about 150 Celsius, preferably about 80 Celsius to about 110 Celsius. The ‘haul- off’ rollers 224 are provided to pull the fibres through the stages of figures 1 and 2. The haul-off rollers 224 provide the additional function of tensioning the fibres, preferably only gently tensioning so as not to deform or break the fibres. However, the surface of the haul-off rollers 224 can be susceptible to degradation if the temperature of the composite tape 228 is too high, e.g., above about 90 or 100 Celsius. Thus, the air knife 218 is a convenient way to impart additional cooling, e.g., to a temperature below about 90 Celsius, which helps prolong the lifespan and effectiveness of the haul-off rollers 224. After being pulled through the haul-off rollers, the composite tape may be further processed to stored, e.g., wound into a roll.

[0116] In other examples of the cooling stage 202, the first rollers 214 may be heated to a temperature that is above room temperature, but below the melting point of the polymer composition. Thus, cooling is still provided with respect to the temperatures of the polymer-impregnation stage 200. In this way, the first rollers still set the polymer matrix within the fibres, but control the cooling so as to impart a desired crystallinity within the polymer matrix. For example, a particular degree of crystallinity may be controlled by using one or more sets of rollers that are heated to a particular temperature in order to define a graduated cooling profile within the polymer-impregnated fibres.

[0117] The volume fraction (Vf) of fibre in fibre-reinforced composite tapes made according to the presently- disclosed method can vary according to the processing conditions and type of polymer used, and / or the application for which the composite tape is being produced. Generally, the Vf of fibre-reinforced composite tapes is in the range of about 45% to about 70%, preferably 47% to 58%, for example 47% or 48%, preferably about 50% to about 62%, for example 55%. The remainder of the volume represents the volume of the polymer matrix, preferably having zero, or substantially zero, voids. Example fibre-reinforced composite production

[0118] A specific example for producing a carbon-fibre reinforced composite tape is now described, with reference to the figures. The resulting composite tape comprises unidirectional carbon fibres.

[0119] Carbon-fibre tows 108 are provided on a creel of bobbins 106. Each bobbin contains a single tow of carbon-fibre filaments. Each tow comprises about 12000 filaments of carbon fibre, where the thickness of each carbon fibre filament in each tow is less than 15pm, or more generally in the range of about 4pm to about 10pm, for example approximately 4pm, or 8pm. The carbon-fibre filaments have a substantially circular cross-section.

[0120] The bobbins turn at substantially the same speed as one another, and the tows are gathered together by anti-twist bars 110. The tows are gathered together in a flattened formation that approximates the dimensions of the composite tape to be produced. The flattened formation of the set of fibres is drawn through a liquid dispersion containing water and particles of the polymer composition comprising a polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK) polymer. Preferably, the PEEK polymer has a repeat unit of formula I:

[0121] -O-Ph-O-Ph-CO-Ph- I 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.

[0122] Alternatively, the polymer composition may comprise a PEEK and polyetherdiphenyletherketone (PEDEK) co-polymer. Preferably, the PEDEK polymer has a repeat unit of formula II

[0123] -O-Ph-Ph-O-Ph-CO-Ph- II wherein Ph represents a phenylene moiety.

[0124] Where the PEEK / PEDEK copolymer is used, preferably the repeat units I and II are in the relative molar properties l:ll of from 65:35 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.

[0125] The set of fibres 112 is submerged / immersed in the dispersion in a container 114. The dispersion is continually mixed to homogenise the particles and thereby impart an even coating of particles. The set of fibres 112 is then drawn out of the dispersion. Excess water is removed by passing the pins over fixed bars (not shown) under an amount of tension and / or through a set of roller 118. A coated set of fibres 120 is thereby formed, i.e., coated with wet particles of a polymer composition comprising PEEK or PEEK / PEDEK copolymer. The coated fibres 120 may have swelled with water, though this swelling is temporary and is reversed in the pre-heating stage 104.

[0126] The coated set of fibres 120 are then drawn through an oven 122 having an internal air-temperature of about 360 Celsius. Once the tape exits the first oven 122 the temperature of the coated set of fibres 120 is about 40 to about 50 Celsius. The fibres have also substantially dried and therefore may have contracted. The set of coated fibres 120 is then passed through a second oven 124, which also heats the air inside to about 360 Celsius. Once the tape exits the second oven 124 the temperature of the coated set of fibres 120 is about 200 Celsius.

[0127] The set of coated fibres 120 then enters a third oven 204. The temperature of the oven is above the melting point of the polymer composition, for example, at least 20 Celsius above the melting point.

[0128] Immediately after the set of coated fibres 120 exits the oven 204, the temperature of the composite substantially matches the temperature of said oven. For example, for the PEEK / PEDEK copolymer, the temperature of the set of coated fibres 120 is about 320 Celsius. In general, the polymer composition is at least partially molten, preferably wholly molten after exiting the oven. The polymer is also mobile, i.e., such that it can be readily urged into interstitial gaps between the fibres and achieve good / uniform impregnation thereby forming a continuous and uniform polymer matrix in the resulting composite tape. A ceramic heat shield 208 protects the molten polymer by helping to reduce heat loss from the fibres, thereby ensuring that the polymer stays molten until it reaches the first heated pin. A guide rail 210 which contains a recess helps to urge the fibres together into a desired width prior to reaching the heated pins. The guide rail 210 may not be actively heated, but may nevertheless be hot, e.g., due to the heat shield and / or contact with the hot coated fibres and / or proximity to the oven. The guide rail may not, in some examples, touch a surface of the fibres, i.e., it may simply touch the edges of the set of fibres.

[0129] The temperature of the first heated pin 212a is at least about 20 Celsius above the melting point of the polymer composition. In this example, the heated pins are about 30 to 40 Celsius above the melting point of the polymer composition. For the PEEK / PEDEK copolymer, the temperature of the heated pins is therefore about 340 to about 360 Celsius. The coated fibres are passed over an arc of each of the heated pins on alternating sides of the set of fibres. As the coated fibres pass over the arcs of the heated pins, the heat of the pins helps to maintain a molten and mobile polymer composition. The normal force generated on the surface of the arc of the pins 212a, 212b, 212c (i.e., the force perpendicular to a tangent to the surface of the arc) urges the molten polymer in between the fibres. The thickness of the set of fibres less than about 1 mm, preferably less than 0.5mm), meaning that the heat transfer from each of the heated pins is effective throughout the thickness of the fibres.

[0130] The newly polymer-impregnated set of fibres 226 passes through a water-cooled first roller 214. The fibres pass into the patterned surface of the first roller, and are urged together to form a width. The surface of the first roller 214 is cooled to about 70 Celsius (by water that is about 10 Celsius), thereby cooling the molten polymer to below the melting point, thus setting the polymer into the desired width and thickness. The fibres then pass through second rollers which are water-cooled. It should be appreciated that the water-cooling is internal to the rollers, and no water is used on the surface of the rollers 214, 216. After exiting the second roller 216, the temperature of the polymer-impregnated fibres is about 90 Celsius. The polymer is therefore solidified. The polymer-impregnated fibres are passed under an air knife which provides a cooling jet of air to further cool the fibres to below about 70 Celsius. An inspection device 222 may be provided which may measure the width and / or thickness of the fibres, and / or some other visible property of the composite tape. The resulting fibre-reinforced composite tape is then pulled through haul-off rollers to be stored.

[0131] The exact values of the parameters for the above-described method, such as temperatures of ovens and heated pins, and speed of the travel of fibres, depend on the melting point of the polymer composition used. As such, it would be within the remit of the skilled person to alter the parameters described above as appropriate, depending on the polymer and / or type and / or amount of fibre used, to achieve the advantageously uniform polymer impregnation provided by the presently-disclosed methods.

[0132] Rotating and Static Heated Pins

[0133] In some examples, including in the specific embodiments described above with respect to PEEK or PEEK / PEDEK polymer compositions, the heated pins may rotate with the motion (i.e., direction of travel) of the fibres. The rotation may be idle, i.e., driven and urged to rotate by the movement of the fibres, which may be tensioned to encourage rotation at a matching speed with a speed of travel of the fibres. Alternatively, the heated pins may be motorised to rotate to match the speed of travel of the fibres. In some examples, the heated pins may be motorised to rotate in a direction that matches the direction of travel of the fibres, but at a speed that is faster or slower than the speed of travel of the fibres.

[0134] Figure 3a illustrates an embodiment with two rotating heated pins 300a, 300b. The temperature ranges of the heated pins described above are readily applicable to rotating heated pin embodiments. The fibres are passed over alternating sides of the heated pins. Thus, the two heated pins 300a, 300b rotate in opposite directions. As indicated, the first heated pin 300a rotates anti-clockwise, and the second heated pin 300b rotates clockwise. If there were a third rotating pin indicated, it would again rotate anticlockwise.

[0135] The inventors have established that rotating the heated pins to match the direction of travel of the fibres imparts a glossy surface onto the resulting fibre-reinforced composite tape. Consequently, it is advantageous to pass both sides of the set of fibres over alternating sides of the heated pins in order that both surfaces of the composite tape obtain a glossy surface. Another term for ‘glossy’ may be ‘smooth’. Some manufacturing applications that use fibre-reinforced composite tapes obtain advantages from using glossy / smooth tape. For example, laminates made from building layers of glossy / smooth tape together can have improved inter-sheet bonding strength, and / or in some cases can be faster to layup. Moreover, laminates made using glossy tape can, in embodiments, be better suited to in-situ processing. Generally, some embodiments of glossy fibre-reinforced composite tapes can deliver higher interlaminate shear strength than non-glossy composite tapes. In particular, laminates made from glossy tapes can be advantageously disposed towards laminating techniques that do not require an autoclave, e.g., out-of- autoclave (OOA) consolidation techniques. Thus, glossy composite tapes can advantageously be suited to producing larger lamented components that cannot be manufactured using a vacuum and / or autoclave.

[0136] The reason for this advantage may be, for example, because glossy tapes have a more polymer-rich surface which yields stronger inter-laminate welds, or, more generally, a greater fraction of polymer matrix within the fibres. This corresponds with the inventors establishing that the glossy composite tapes produced using the combination of the aforesaid pins and rollers, advantageously provides an environment that produces a tape having the appearance of a resin rich surface.

[0137] It will be understood by the skilled person that any number of rotating heated pins (i.e., two or more) may be used to impart a glossy surface. For example, an odd number of rotating pins, e.g., three or five pins, are suitable. Using an odd number of rotating pins may impart a marginally more glossy surface on one side of the composite tape than the other due to the unequal number of passes that one side of the tape receives. However, this difference will be negligible and does not impact the quality or functionality of the glossy tape.

[0138] Conversely, in some embodiments the heated pins may be kept static / stationary, i.e., such that the fibres are dragged over an arc of each of the heated pins, and the heated pins do not move relative to the fibres. Again, any number of heated pins (two or more) can be used in these embodiments. The inventors have established that static heated pins impart a texture on the surface of the composite tapes. The texture of the resulting tape, imparted by static pins, is not usually visible to the naked eye but is measurable. In some industries and for some manufacturing methods, matt and / or rough composite tapes are preferred.

[0139] Roughness testing equipment can be used to measure the glossiness or roughness of composite tapes, by measuring surface friction. The handheld roughness meter operates according to the touching method, some of which are compliant with ISO 3274. The roughness / glossiness measuring is a tactile method, in which the probe tip (preferably diamond) of the handheld roughness meter is pulled at a steady / constant speed over the surface of the composite tape. Additionally, a specular gloss meter may be used, which measures gloss by projecting a beam of light at a fixed intensity and angle onto a surface of the composite tape and measuring an amount of reflected light at the corresponding reflected angle position. Dispersion

[0140] The method comprises passing a set of fibres through a dispersion comprising particles of a polymeric composition comprising a first thermoplastic in the liquid comprising water.

[0141] 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, 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.

[0142] Preferably, the type of polymeric dispersion used in the dispersion according to present embodiments uses a first thermoplastic comprising polyaryletherketones (PAEK). Preferably, the amount of PAEK particles in the dispersion is in the range of about 5 wt.% to about 50 wt.%, preferably 10 wt.% to about 30 wt.%, for example 15 wt.% to about 25 wt.% by weight of the dispersion liquid.

[0143] In one example, the dispersion liquid comprises water in a range from about 50 wt.% to about 100 wt.%, preferably in the range of about 80 wt.% to about 100 wt.%, preferably in a range from about 85 wt.% to about 99 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.

[0144] 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.

[0145] Thus, in one example, the liquid comprises a dispersion agent in a range from 0 wt.% to 20 wt.%, preferably in a range from about 1 wt.% to about 15 wt.%, more preferably in a range from about 2.5 wt.% to about 10 wt.%, by weight of the liquid. 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 may improve the separation of the particles and / or prevent settling and / or clumping of the particles. In one example, the dispersion agent 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- Methoxy-2-propanol, Sodium Nitrate, Benzotriazole, 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, sodium dioctyl sulphosuccinate, or a mixture thereof.

[0146] 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 15 wt.%, more preferably in a range from about 0.1 to about 2.5 wt.% by weight of the liquid.

[0147] Fibre-reinforced composite material

[0148] Preferably, the reinforcement fibres that are used to form fibre-reinforced composite tapes or other composite articles have a diameter in a range from about 2 pm to about 100 pm, preferably in a range from about 4 pm to about 50 pm, more preferably in a range from about 5 pm to about 20 pm, most preferably in a range from about 4 pm to about 10 pm.

[0149] 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, in particular a copolymer formed of PEEK and PEDEK.

[0150] Preferably, the polymeric composition contains a PAEK polymer wherein the first thermoplastic comprises a PEEK polymer or a PEEK / PEDEK copolymer.

[0151] Preferably, the polymeric composition comprises PEEK / PEDEK copolymers prepared as described in US 4717761 , WO 2014 / 207458 A1 and WO 2015 / 124903 A1 , the contents of which are incorporated herein by reference.

[0152] WO 2014 / 207458 A1 discloses PEEK / PEDEK copolymers, which have repeat units of formula I and II in a molar proportion from 55:45 to 95:5 and with an MV measured at 340°C and 1000s-1shear rate of at least 0.25 kNsm-2and less than 1 .2 kNsm-2.

[0153] WO 2015 / 124903 A1 discloses PEEK / PEDEK copolymers which have repeat units of formula I and II in a molar ratio from 55:45 to 95:5 and an MV of at least 0.25 and less than 1 .2 measured at 340°C and at 1000s-1shear rate. In some embodiments, the polymeric composition may be as described in WO 2020 / 141329 A1 , the contents of which are incorporated herein by reference. In such embodiments, the polymeric composition may have a repeat unit of formula la:

[0154] And repeat units of formula Ila: wherein at least 95 mol% of the repeat units are repeat units of formula la and of formula Ila; wherein the repeat units la and Ila have a molar ratio la: I la from 65:35 to 95:5 or from 55:45 to 80:20.

[0155] In other words, in the polymeric composition, 95 mol% of all repeat units present are units of formula la and of formula Ila in the specified molar ratio la:lla from 55:45 to 80:20. This may be established by virtue of knowledge of the numbers of moles of monomers employed in in the preparation of the polymer.

[0156] The phenylene moieties in each repeat unit la and Ila have 1 ,4- para linkages to atoms to which they are bonded. This results in the polymeric composition being crystalline in nature.

[0157] Suitably in such embodiments the polymeric composition has an MV of from 0.35 to 0.55 kNsm-2as measured using capillary rheometry at 400°C at a shear rate of 1000s-1by extrusion through a tungsten carbide capillary die of 0.5mm diameter and 8.0 mm length.

[0158] Preferably, the MV of the polymeric composition, measured at 1000s-1and at 400°C as described above is from 0.15 to 0.50 kNsm-2.

[0159] Preferably, the molar ratio la: Ila is from 60:40 to 75:25.

[0160] Preferably, at least 98 mol% of the repeat units are repeat units of formula la and of formula Ila, more preferably 99 mol %. Most preferably, the polymeric composition consists essentially of repeat units of formula la and formula Ila.

[0161] 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%.

[0162] 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%. 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.

[0163] Within this specification, references to ‘melting point’ or ‘melting temperature’ mean a temperature at which a material transitions from a solid state to a molten state as measured by differential scanning calorimetry (DSC).

[0164] 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.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] 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 producing a fibre-reinforced composite tape comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) coating a set of reinforcement fibres in the dispersion, thereby obtaining a set of coated reinforcement fibres; c) pre-heating the set of coated reinforcement fibres; d) passing a length of the coated reinforcement fibres over an arc of each of a plurality of heated pins, wherein each of the plurality of heated pins is heated to a polymer-impregnation temperature, thereby obtaining a length of polymer-impregnated reinforcement fibres; and e) cooling the length of polymer-impregnated reinforcement fibres to obtain a length of fibre- reinforced composite tape, wherein the polymer-impregnation temperature is greater than or equal to a melting point of the first thermoplastic.

2. The method of claim 1 , wherein, during step d), the plurality of heated pins melt at least some of the particles of a polymeric composition to form a molten polymeric composition and urge a portion of the molten polymeric composition in between the reinforcement fibres to thereby obtain the length of polymer-impregnated reinforcement fibres.

3. The method of claim 1 or 2, wherein pre-heating the set of coated reinforcement fibres comprises subjecting the set of coated reinforcement fibres to a temperature of at least about 20 Celsius below the melting point of the first thermoplastic, preferably about 10 Celsius below the melting point of the first thermoplastic, preferably about a melting point of the first thermoplastic, more preferably to about the polymer-impregnation temperature.

4. The method of any preceding claim, wherein a surface of each of the first and second heated pins has a temperature between about 5 to about 50 Celsius above the melting point of the first thermoplastic.

5. The method of any preceding claim, wherein each of the plurality of heated pins are separated along a direction of travel of the length of the coated reinforcement fibres, and wherein step d) comprises: passing a first surface of the length of coated reinforcement fibres over an arc of a first heated pin, and passing a second surface of the length of coated reinforcement fibres, opposing the first surface, over an arc of a second heated pin.

6. The method of any preceding claim, wherein the fibres of the set of reinforcement fibres are tensioned during at least step d), preferably tensioned during each of steps b), c), d), preferably also tensioned during step e).

7. The method of any preceding claim, wherein an insulating heat shield is disposed immediately before a position of a first heated pin of the plurality of heated pins along a direction of travel of the coated set of reinforcement fibres.

8. The method of any preceding claim, wherein step c) comprises passing alternately opposing sides of the length of the coated reinforcement fibres over successive alternating heated pins of the plurality of heated pins.

9. The method of any preceding claim, wherein a temperature of the final heated pin of the plurality of heated pins, over which the length of the coated reinforcement fibres passes, is at least about 10 Celsius to about 60 Celsius above the melting point of the first thermoplastic, preferably at least about 25 Celsius to about 50 Celsius above the melting point of the first thermoplastic.

10. The method of any preceding claim, wherein at least some of the plurality of heated pins are heated by providing at least one heat cartridge within an internal cavity of each of the heated pins.

11. A method for producing a fibre-reinforced composite having a smooth and / or glossy surface, comprising: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) coating a set of reinforcement fibres in the dispersion, thereby obtaining a set of coated reinforcement fibres; c) pre-heating the set of coated reinforcement fibres; d) passing a length of the coated reinforcement fibres over an arc each of a plurality of heated pins, wherein each heated pin of the plurality of heated pins is heated to a polymer- impregnation temperature, thereby obtaining a length of polymer-impregnated reinforcement fibres; and e) cooling the length of polymer-impregnated reinforcement fibres thereby consolidating the fibres to obtain a length of fibre-reinforced composite tape, wherein each heated pin of the plurality of heated pins rotates, in step d), with respect to a movement of the coated reinforcement fibres, and wherein the polymer-impregnation temperature is equal to or greater than a melting point of the first thermoplastic.

12. A method for producing a fibre-reinforced composite having a roughened surface, comprising the steps: a) providing a dispersion in a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic; b) coating a set of reinforcement fibres in the dispersion, thereby obtaining a set of coated reinforcement fibres; c) pre-heating the set of coated reinforcement fibres;d) passing a length of the coated reinforcement fibres over an arc of each of a plurality of heated pins, wherein each of the plurality of heated pins is heated to a polymer-impregnation temperature, thereby obtaining a length of polymer-impregnated reinforcement fibres; and e) cooling the length of polymer-impregnated reinforcement fibres thereby consolidating the fibres to obtain a length of fibre-reinforced composite tape, wherein the plurality of heated pins are static with respect to a movement of the coated reinforcement fibres, and wherein the polymer-impregnation temperature is equal to or greater than a melting point of the first thermoplastic.

13. A method of any preceding claim wherein the first thermoplastic comprises a PAEK selected from polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketoneetherketoneketone (PEKEKK), polyetherimide (PEI), polyetherdiphenyletherketone (PEDEK), and combinations thereof14. A fibre-reinforced composite tape produced according to any of the preceding claims.

15. A fibre-reinforced composite tape manufacturing apparatus comprising: a) a container arranged to contain a dispersion comprising water and particles of a polymeric composition comprising a first thermoplastic; b) a heating device configured to pre-heat a set of coated reinforcement fibres; c) a plurality of heated pins, each of which is configured to allow a length of coated reinforcement fibres to pass over an arc of said heated pin; and d) a cooling zone configured to cool a length of length of polymer-impregnated reinforcement fibres; wherein each heated pin of the plurality of heated pins is configured to be heated to a polymer- impregnation temperature being equal to or greater than a melting point of the first thermoplastic.

16. A polymeric dispersion as claimed in any one of the preceding claims comprising a liquid comprising water, the dispersion comprising particles of a polymeric composition comprising a first thermoplastic as claimed in any one of the preceding claims.

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