Fiber-reinforced composite methods

Abstract

1. A method for providing a pre-impregnated tape (15) comprising reinforcing fibers (11) for the manufacture of a fiber-reinforced composite part, the method comprising: non-uniformly impregnating (14) an additive composition into and / or onto a tape (13) comprising reinforcing fibers (13) to provide the pre-impregnated tape, wherein the additive composition comprises a resin and an additive.

Description

[Technical Field]

[0001] The present invention relates to tapes with reinforcing fibers for the production of fiber reinforced composite parts, and in particular to pre-impregnated tapes with reinforcing fibers for the production of fiber reinforced composite parts. [Background technology]

[0002] Automated layup of fiber-reinforced composites, such as by automated tape layup (ATL) and automated fiber placement (AFP), typically involves laying fiber tapes, fabrics, or tows in a mold using, for example, a robot or CNC machine. The tapes, fabrics, and tows can be fused with a binder or impregnated with a resin (also known as prepregs). Layup of fiber-reinforced composite parts can be accelerated by laying multiple courses simultaneously, laying multiple tapes or tows simultaneously, and / or increasing the width of the tapes, fabrics, or tows. ATL typically uses relatively wide tape (also known as fabric or cloth) of 2, 3, 6, 12, or 24 inches (formally 51, 76, 152, 305, or 610 mm), while AFP typically uses relatively narrow tow (also known as ribbon) of 1 / 8, 1 / 4, 1 / 2, or 1 inch (3.17, 6.35, 12.7, or 25.4 mm), although there is a movement toward wider tow widths up to 1.5 inches (38.1 mm). The choice of tape, fabric, or tow width is usually limited by the part curvature in two or three dimensions.

[0003] Functional tapes (including graded functional tapes) can be used to transition between two different fiber-reinforced composite parts with different properties, e.g., different dielectric properties. Typically, functional tapes include functional additives, such as electrically and / or thermally conductive, magnetic, and / or structural particles, in the resin of a pre-impregnated tape, and / or one or more functional layers in a tape, such as a pre-impregnated tape, to change the tape's properties, e.g., electrical, thermal, magnetic, and / or structural properties. Grading (also known as gradation or tapering) the functional additives and / or functional layers can change the properties across the width and / or along the length of the functional tape. In a specific example, tapering electrical conductivity may be required to allow a dielectric component (e.g., a radome) to integrate with a carbon fiber structural component of an airframe.

[0004] Conventional methods for providing functional tapes with reinforcing fibers for the production of fiber-reinforced composite parts are relatively complex, expensive, and / or energy intensive. For example, conventional methods for providing tapes with tapered resistivity rely on sputtering of conductive particles onto pre-impregnated tapes that are then integrated into the ply buildup.

[0005] Therefore, there is a need for improved production of tapes with reinforcing fibers for the production of fiber-reinforced composite parts. Summary of the Invention

[0006] A first aspect provides a method of providing a pre-impregnated tape for the manufacture of a fiber-reinforced composite part, the method comprising non-uniformly impregnating an additive composition into and / or on the tape to provide the pre-impregnated tape, wherein the additive composition comprises a resin and an additive, and wherein the tape comprises reinforcing fibers.

[0007] In this manner, pre-impregnated tapes can be used to transition between fiber-reinforced composite parts with different properties, e.g., different dielectric properties. For example, a gradual decrease in electrical conductivity may be required to allow integration of a dielectric component (e.g., a radome) with a carbon fiber structural component of an airframe. Other applications include EMI / RFI shielding, lightning strike protection, and coordinated functionality. By impregnating the additive composition into and / or onto the tape to provide a pre-impregnated tape, the method according to the first embodiment is relatively simple, inexpensive, and / or less energy-intensive than conventional methods of providing tapes with reinforcing fibers for the manufacture of fiber-reinforced composite parts. Specifically, the method according to the first embodiment allows for a gradual decrease in resistance within one single ply, thereby reducing the complexity and characteristics required at various points in a fiber-reinforced composite part (e.g., a composite aircraft part such as an airframe). For example, by depositing the additive non-uniformly in and / or on the tape during its impregnation, such as by grading the deposition, patterning, and / or masking the additive, a non-uniform deposition of the additive is provided to provide a tape with graded or patterned properties, such as the electrical, thermal, magnetic, and / or structural properties of the pre-impregnated tape. In other words, such properties of the pre-impregnated tape are tailored or customized, such as tapered electrical conductivity to enable integration of a dielectric component (e.g., a radome) with a carbon fiber structural component of an airframe. For example, while the method according to the first aspect allows for variable properties, such as conductivity, across a single reel of material, the method can be modified in-line to produce custom reels.

[0008] The tape may be provided as a woven and / or knitted continuous fiber tape, or may be provided by spreading one or more tows, for example.

[0009] In one example, the tape comprises aligned reinforcing fibers and / or continuous reinforcing fibers, such as woven and / or knitted continuous fibers. In one example, the tape is dry (i.e., does not have resin impregnated therein and is not pre-impregnated) before the additive composition is non-uniformly impregnated into and / or onto the tape comprising the reinforcing fibers to provide a pre-impregnated tape. In one example, the tape is at least partially pre-impregnated (i.e., has at least some resin impregnated therein) before the additive composition is non-uniformly impregnated into and / or onto the tape comprising the reinforcing fibers to provide a pre-impregnated tape.

[0010] In one example, the method comprises providing a tape by spreading out one or more tows (i.e., untwisted bundles of continuous reinforcing fibers, such as provided on a spool) comprising reinforcing fibers.

[0011] It should be understood that the tape is permeable or semi-permeable to the resin, but at most semi-permeable to the additive, thereby allowing at least some of the additive to be deposited therein and / or thereon, for example, within the reinforcing fibers and / or the pores therebetween.

[0012] In one example, the additive comprises and / or is a functional additive (i.e., having the required electrical, thermal, magnetic, and / or structural properties to impart the respective desired properties of the pre-impregnated tape for the fiber-reinforced composite part). In one example, the additive comprises and / or is a particle. In one example, the additive comprises and / or is an electrically conductive particle, including metal particles such as Au, Ag, Ni, Cu, Al, etc., and / or non-metallic particles such as graphene, reduced graphene oxide, conductive oxides, etc. In one example, the additive comprises and / or is a nanoparticle, microparticle, nanowire, nanosheet, or flake.

[0013] In one example, the metal is a transition metal, such as a first-, second-, or third-row transition metal. In one example, the metal is Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, or Zn. In one example, the metal is Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, or Cd. In one example, the metal is Hf, Ta, W, Re, Os, Ir, Pt, Au, or Hg. In one example, the metal is a lanthanide. In one example, the metal is La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu. In one example, the metal is an actinide. In one example, the metal is Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, or Es.

[0014] In one example, the additive comprises a metal, such as a pure or unalloyed metal, or an alloy thereof, such as any metal that can be fused by melting. The metal may comprise powder particles, such as a pure metal or an alloy, such as any metal from particles, such as produced by atomization.

[0015] These powder particles can be produced by atomization, such as gas atomization or water atomization, or other processes known in the art.

[0016] In one example, the additive comprises an inorganic compound. Inorganic compounds, such as ceramics comprising functional metals, can include, for example, oxides, silicates, sulfides, sulfates, halides, carbonates, phosphates, nitrides, borides, and hydroxides of the metal. These inorganic compounds can also include a second such metal, for example, a mixed oxide, such as a mixture of barium titanate and strontium titanate, such as (Ba,Sr)TiO. Additives include TCP (tricalcium phosphate), MCP (monocalcium phosphate), DCP (dicalcium phosphate), tetracalcium phosphate, hydroxyapatite, alpha-TCP, beta-TCP, titanium oxide (titania), aluminum oxide (alumina), zirconium oxide (zirconia), yttrium oxide (yttria), yttria-stabilized zirconia, indium oxide, indium tin oxide, boron nitride, silicon carbide, boron carbide, tungsten carbide, beryllium oxide, zeolite, cerium oxide (ceria), tungsten disilicide, sodium silicate, platinum silicate, and silica nitride. The additive may comprise ammonium, tungsten nitride, vanadium nitride, tantalum nitride, niobium nitride, silicon boride, barium titanate, lead zirconate titanate, zinc oxide, potassium niobate, lithium niobate, sodium tungstate, sodium chloride, sodium nitride, potassium nitride, potassium chloride, magnesium chloride, calcium chloride, calcium nitride, magnesium nitride, strontium oxide, strontium phosphate, strontium titanate, calcium sulfate, barium sulfate, calcium carbonate, sodium carbonate and / or sodium fluoride, or mixtures thereof.

[0017] Preferably, the additive comprises a transition metal and / or an oxide thereof.

[0018] The additive particles can have regular shapes, such as spherical, cubic, or rod-like, and / or irregular shapes (also known as morphologies), such as spheroidal, flake-like, or granular.

[0019] The inventors have determined that the size of the additive particles, e.g., diameter (or largest dimension of the aggregates), can affect their dispersibility in the additive composition and / or in and / or on the pre-impregnated tape. Non-uniform dispersibility in the additive composition can lead to undesirable non-uniformity in the pre-impregnated tape. Such undesirable non-uniformity in the pre-impregnated tape may not be suitable for the pre-impregnated tape. Relatively small particles can adversely affect viscosity. Relatively large particles can lead to clogging.

[0020] At least 50% by weight of the additive particles may have a diameter of up to 100 nm. For regular shapes, diameter may refer, for example, to the diameter of a sphere or rod, or to one side of a rectangular prism. Diameter may also refer to the length of a rod. For irregular shapes, diameter may refer, for example, to the largest dimension of the particle. Preferably, particle size distribution is measured using light scattering measurement of the particles on an instrument such as a Malvern Mastersizer 3000, configured to measure particle sizes from 10 nm to 3500 micrometers, using particles wet dispersed in a suitable carrier liquid (with a suitable dispersant compatible with the particle surface chemistry and the liquid chemistry) according to the instrument manufacturer's instructions, assuming a uniform particle density.

[0021] In one example, the additive particles comprise and / or are nanoparticles having a diameter in the range of 1 nm to 100 nm, preferably in the range of 10 nm to 90 nm, more preferably in the range of 15 nm to 85 nm, and most preferably in the range of 25 nm to 75 nm, e.g., 50 nm. In one example, the additive particles comprise and / or are nanoparticles in which at least 50% by weight of the nanoparticles have a diameter in the range of 1 nm to 100 nm, preferably in the range of 10 nm to 90 nm, more preferably in the range of 15 nm to 85 nm, and most preferably in the range of 25 nm to 75 nm, e.g., 50 nm. In one example, the additive particles comprise and / or are nanoparticles in which at least 90% by weight of the nanoparticles have a diameter in the range of 1 nm to 100 nm, preferably in the range of 10 nm to 90 nm, more preferably in the range of 15 nm to 85 nm, and most preferably in the range of 25 nm to 75 nm, e.g., 50 nm. In one example, the additive particles comprise and / or are nanoparticles in which at least 95% by weight of the nanoparticles have a diameter in the range of 1 to 100 nm, preferably in the range of 10 to 90 nm, more preferably in the range of 15 to 85 nm, and most preferably in the range of 25 to 75 nm, e.g., 50 nm. In one example, the additive particles comprise and / or are nanoparticles in which at least 99% by weight of the nanoparticles have a diameter in the range of 1 to 100 nm, preferably in the range of 10 to 90 nm, more preferably in the range of 15 to 85 nm, and most preferably in the range of 25 to 75 nm, e.g., 50 nm.

[0022] Particles of these sizes may be referred to as nanoparticles. Generally, nanoparticles tend to aggregate to reduce surface energy. Agglomerates are collections of particles with varying numbers, and the aggregates may vary, for example, in particle number and / or shape. Nanopowders are solid powders of nanoparticles, often containing micron-sized nanoparticle aggregates. These aggregates can be redispersed (at least to some extent) in the solid state, for example, using ultrasonic processing. Nanoparticle dispersions are suspensions of nanoparticles in a liquid, such as water or an organic solvent / organic matrix carrier. Agglomeration may depend, for example, on temperature, pressure, pH, and / or viscosity. Particle agglomeration can lead to uneven particle dispersibility in the additive composition. Therefore, a suitable particle size can be a compromise between reducing agglomeration and avoiding clogging during use, while achieving uniform dispersibility and the desired distribution on and / or within the pre-impregnated tape. Furthermore, the shape of the particles (nanopowder or suspension) can affect their dispersibility in the additive composition.

[0023] In one example, the additive particles comprise and / or are microparticles having a diameter in the range of 1 μm to 1000 μm, preferably 100 μm to 900 μm, more preferably 150 μm to 850 μm, and most preferably 250 μm to 750 μm, such as 500 μm. In one example, the additive particles comprise and / or are microparticles wherein at least 50% by weight of the microparticles have a diameter in the range of 10 μm to 1000 μm, preferably 100 μm to 900 μm, more preferably 150 μm to 850 μm, and most preferably 250 μm to 750 μm, such as 500 μm. In one example, the additive particles comprise and / or are microparticles in which at least 90% by weight of the microparticles have a diameter in the range of 10 μm to 1000 μm, preferably 100 μm to 900 μm, more preferably 150 μm to 850 μm, and most preferably 250 μm to 750 μm, such as 500 μm. In one example, the additive particles comprise and / or are microparticles in which at least 95% by weight of the microparticles have a diameter in the range of 10 μm to 1000 μm, preferably 100 μm to 900 μm, more preferably 150 μm to 850 μm, and most preferably 250 μm to 750 μm, such as 500 μm. In one example, the additive particles comprise and / or are microparticles in which at least 99% by weight of the microparticles have a diameter in the range of 10 μm to 1000 μm, preferably in the range of 100 μm to 900 μm, more preferably in the range of 150 μm to 850 μm, and most preferably in the range of 250 μm to 750 μm, e.g., 500 μm.

[0024] In one example, the additive particles comprise and / or are nanoparticles and microparticles, as described above. In one example, the additive particles comprise microparticles in the range of 99% to 1%, preferably 90% to 10%, more preferably 75% to 25% by weight of the particles, and nanoparticles in the range of 99% to 1%, preferably 90% to 10%, more preferably 75% to 25% by weight of the particles, e.g., the balance nanoparticles. In one example, the additive particles consist of nanoparticles and microparticles, as described above.

[0025] It should be understood that the reinforcing fibers provide a substrate for the additive and can be the same as or different from the reinforcing particles of the fiber-reinforced composite part. In one example, the reinforcing fibers comprise and / or are electrically insulating reinforcing fibers. In one preferred example, the reinforcing fibers comprise and / or are electrically insulating reinforcing fibers and the additive comprises and / or is electrically conductive particles. In this manner, the electrical properties of the pre-impregnated tape can be graded or patterned, for example, across its width and / or along its length, to transition between two different fiber-reinforced composite parts having different properties, e.g., different dielectric properties, as described above.

[0026] In one example, the reinforcing fibers comprise and / or are electrically conductive reinforcing fibers. In one preferred example, the reinforcing fibers comprise and / or are electrically conductive reinforcing fibers and the additive comprises and / or is electrically insulating particles. In this manner, the electrical properties of the pre-impregnated tape can be graded (e.g., tapered) or patterned, as described above, for example across its width and / or along its length, to transition between two different fiber-reinforced composite parts having different properties, e.g., different dielectric properties.

[0027] In one example, the reinforcing fibers may comprise non-metallic fibers, such as glass fibers, such as A-glass, E-glass, E-CR-glass, C-glass, D-glass, R-glass, S-glass, S-2-glass, and HS-glass; carbon fibers, such as aerospace or industrial grade IM2A, IM2C, IM5, IM6, IM7, IM8, IM9, IM10, AS4, AS4A, AS4C, AS4D, AS7, HM50, and HM63; aramid fibers, such as Kevlar®, Nomex®, and Technora®; ultra-high molecular weight polyethylene (UHMwPE) fibers, such as Dyneema®; basalt fibers, such as BasFiber® or Wiking® Super B; and / or mixtures thereof. In one example, the reinforcing fibers comprise metal and / or alloy fibers, such as titanium, aluminum, and / or copper, and / or alloys thereof; stainless steel fibers; and / or mixtures thereof. In one example, the reinforcing fibers comprise a mixture of non-metallic and metallic fibers.

[0028] In one example, the diameter of the reinforcing fibers is in the range of 2 μm to 100 μm, preferably in the range of 4 μm to 50 μm, more preferably in the range of 5 μm to 20 μm, and most preferably in the range of 6 μm to 10 μm, for example, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm. Typically, suitable carbon fiber diameters are in the range of 5 μm to 10 μm, and suitable glass fiber diameters are in the range of 4 μm to 20 μm.

[0029] In one example, the volume fraction of reinforcing fibers, V f is in the range of 50% to 100% relative to the volume of the pre-impregnated tape, preferably in the range of 60% to 95%, for example 70%, 80% or 90%. In this way, a relatively high volume fraction V of reinforcing fibers in the pre-impregnated tape can be achieved. f can be provided.

[0030] In one example, the volume fraction of reinforcing fibers, V fis in the range of 30% to 90%, preferably in the range of 40% to 80%, more preferably in the range of 40% to 70%, e.g., 40%, 45%, 50%, 55%, 60%, 65% or 70%, relative to the volume of the fiber-reinforced composite part. Generally, the volume fraction V of the matrix, e.g., the first polymer composition, is m is V f +V m = 1, the volume fraction V of the reinforcing fibers, e.g., the first set of reinforcing fibers f Thus, a relatively high volume fraction of reinforcing fibers in a fiber-reinforced composite part, V f can be provided.

[0031] In one example, the tape comprises aligned reinforcing fibers and / or continuous reinforcing fibers, for example, woven and / or knitted continuous fibers. In one example, the length of the reinforcing fibers is at least 2 mm, preferably at least 10 cm, more preferably at least 1 m, and most preferably at least 10 m. It should be understood that the length of the reinforcing fibers refers to the total length of each reinforcing fiber. That is, the reinforcing fibers comprise and / or are continuous fibers. In one example, impregnating the tape with a resin containing an additive comprises differentially impregnating the tape with the resin containing the additive. In this way, the content (i.e., concentration, level, amount, type) of the additive impregnated in and / or on the tape varies in different areas (i.e., portions, areas, volumes, cross-sections) of the tape.

[0032] In one example, the method comprises controlling the additive content in the additive composition, such that the additive content (i.e., concentration, level, amount, type) in the additive composition is controlled, for example, to locally impregnate the resin in the tape with different additive content.

[0033] In one example, controlling the content (i.e., concentration, level, amount, type) of additive in the additive composition comprises using a masterbatch containing the additive. It should be understood that a masterbatch contains additive in a resin at a relatively high content (i.e., concentration, level, amount, type), e.g., a predetermined content provided by the masterbatch supplier. In one example, using a masterbatch comprises compounding or mixing the masterbatch with additional resin (e.g., resin without additives), e.g., using a static and / or dynamic blender and / or mixer. Suitable static and / or dynamic blenders and / or mixers are known.

[0034] In one example, non-uniformly impregnating the additive composition into and / or on the tape comprises controlling the flow rates of the masterbatch and / or the additional resin, for example, by varying the flow rates of the masterbatch and / or the additional resin, respectively, linearly, non-linearly, periodically, and / or aperiodically across the width and / or along the length of the tape.

[0035] In one example, non-uniformly impregnating the additive composition into and / or on the tape comprises impregnating the additive composition through a set of nozzles, including a first nozzle. In this manner, the additive composition can be locally impregnated relative to the tape according to the position of the set of nozzles, e.g., the first nozzle. In this manner, a predetermined pattern of additive composition impregnation in and / or on the tape can be imparted by moving the set of nozzles, e.g., the first nozzle, relative to the tape. The movement of the set of nozzles, e.g., the first nozzle, can be computer-controlled, where it should be understood that each nozzle in the set can be moved either dependently or independently of one another.

[0036] In one example, the set of nozzles includes a second nozzle, and herein, impregnating the additive composition via the set of nozzles including the first nozzle and the second nozzle comprises impregnating the first additive composition having a first content of the additive via the first nozzle and impregnating the second additive composition having a second content of the additive via the second nozzle, where the first content of the additive and the second content of the additive are different from each other. In this way, additive compositions (i.e., the first resin and the second resin) with different contents of the additive (i.e., concentration, level, amount, type) can be impregnated into the tape simultaneously (i.e., simultaneously and in parallel) and / or continuously at different positions, for example, across the entire width of the tape and / or along the length. Further and / or alternatively, the additives included in the first additive composition and the second additive composition can be different. In one example, the set of nozzles includes N nozzles, where N is a natural number of 1 or more, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more, in order to impregnate N types or <N types of resins with different contents of the additive simultaneously (i.e., simultaneously and in parallel) and / or continuously.

[0037] In one example, impregnating the additive composition non-uniformly into and / or onto the tape via the set of nozzles including the first nozzle comprises moving the first nozzle relative to the tape. In this way, the tape can be patterned using the additive composition. In one example, moving the first nozzle relative to the tape comprises moving the first nozzle in a lateral direction, for example, perpendicular to the length of the tape, while spooling the pre-impregnated tape, as will be described later.

[0038] In one example, non-uniformly impregnating the additive composition into and / or on the tape comprises wiping the additive composition across and / or along the tape, e.g., using a wiper. In this way, the distribution of the additive composition is controlled, e.g., to improve its uniformity and / or to improve its non-uniformity, e.g., to improve its non-uniform distribution according to a predetermined pattern.

[0039] In one example, a method comprises non-uniformly impregnating an additive composition into and / or on a tape, optionally curing and / or cooling the additive composition impregnated in the tape, and spooling the pre-impregnated tape. Thus, a reel-to-reel method for providing functionalized pre-impregnated tape is provided, thereby facilitating and / or reducing costs of providing relatively long lengths of functionalized pre-impregnated tape, e.g., at least 1 m, 2 m, 3 m, 4 m, 5 m, 6 m, 7 m, 8 m, 9 m, 10 m, 20 m, 30 m, 40 m, 50 m, 60 m, 70 m, 80 m, 90 m, 100 m, 200 m, 300 m, 400 m, 500 m, 600 m, 700 m, 800 m, 900 m, 1000 m or more.

[0040] The method comprises non-uniformly impregnating the additive composition into and / or onto the tape. In this manner, deposition of the additive composition into and / or onto the pre-impregnated tape is controlled. In this manner, non-uniform impregnation of the additive composition into and / or onto the tape controls the properties of the functionalized pre-impregnated tape, as described above. It should be understood that non-uniform impregnation of the additive composition into and / or onto the tape results in a non-uniform distribution of the deposited additive across the width and / or along the length of the tape, such that the content (i.e., concentration, level, amount, type) of the deposited additive varies across the width and / or along the length of the pre-impregnated tape, for example, according to a predetermined non-uniform distribution or pattern (i.e., controlled as compared to random), e.g., by a factor of at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or more across the width and / or along the length of the pre-impregnated tape. In contrast, uniform impregnation of the additive composition in and / or on the tape results in a uniform distribution of the deposited additive across the width and / or along the length of the tape such that the content (i.e., concentration, level, amount, type) of the deposited additive varies across the width and / or along the length of the pre-impregnated tape by, for example, a factor of at most 2, 1.75, 1.5, 1.25, 1.1, 1.05, or less across the width and / or along the length.

[0041] In one example, non-uniformly impregnating the additive composition in and / or on the tape comprises non-uniformly impregnating the additive composition in and / or on the tape across its width and / or length. In this manner, the properties of the pre-impregnated tape can be graduated (e.g., graded or tapered, e.g., linearly or non-linearly) or patterned (e.g., periodically or aperiodically) across its width and / or along its length, for example, to transition between fiber-reinforced composite components having different properties, e.g., different dielectric properties, as described above.

[0042] In one example, non-uniformly impregnating the additive composition into and / or on the tape comprises depositing the additive into and / or on the periphery (i.e., edge) of the tape, for example, for a printed circuit board (PCB).

[0043] In one example, non-uniformly impregnating the additive composition into and / or on the tape comprises patterning and / or masking the tape, for example, using a pattern and / or mask. In this way, the additive is deposited to conform to the pattern and / or mask. It should be understood that patterning includes masking. Patterning can be controlled, for example, programmatically, by controlling the flow rate and / or using a mask, as will be understood by those skilled in the art, and masking uses a mask to obscure a region (i.e., a portion, area, volume, cross-section) of the tape. In one example, masking the tape comprises placing a mask upstream of the tape (i.e., with respect to the impregnating additive composition), for example, near the tape, facing the tape, or in contact with the tape. In this way, the fidelity of the conformity of the deposited additive to the mask is improved.

[0044] In one example, non-uniformly impregnating the additive composition into and / or onto the tape comprises applying a magnetic field and / or an electric field while impregnating the additive composition into and / or onto the tape. In this way, deposition of the additive into and / or onto the tape is further controlled. In one example, applying a magnetic field and / or an electric field while impregnating the additive composition into and / or onto the tape comprises applying a magnetic field and / or an electric field parallel or transverse to the impregnating resin.

[0045] In one example, non-uniformly impregnating the additive composition into and / or on the tape comprises depositing the additive within the reinforcing fibers and / or the pores therebetween.

[0046] In one example, the method comprises reacting the additive. In this way, the additive reacts after being deposited in and / or on the pre-impregnated tape. In one example, the method comprises functionalizing the additive. In this way, the non-particles are functionalized after being deposited in and / or on the pre-impregnated tape. For example, metal oxide particles can be reduced to metal particles.

[0047] In one example, the method comprises dispersing and / or suspending particles in an additive composition, such as a resin, as previously described.

[0048] In one example, non-uniformly impregnating the additive composition into and / or on the tape comprises pouring, spraying, or pumping the additive composition into the tape, for example, using a pump. Methods for impregnating tapes with resins are known.

[0049] In one example, non-uniformly impregnating the additive composition in and / or on the tape comprises orienting the tape at an angle relative to the impregnating additive composition, thus resulting in a non-uniform distribution of the deposited additive across the width and / or along the length of the tape.

[0050] In one example, the resin comprises a first polymer composition, as described below.

[0051] In one example, the reinforcing fibers are at least partially surrounded by the first polymer composition, for example when the tape is a prepreg. In this way, the handling properties of the pre-impregnated tape are improved. In one example, the tape is a pre-impregnated tape. In one example, the tape is dry, i.e., not at least partially surrounded by the first polymer composition.

[0052] Typically, prepregs are "pre-impregnated" reinforcement fibers that already have a thermosetting polymer matrix material, such as epoxy, or a thermoplastic resin matrix. The fibers can be in a woven form, and the matrix is ​​used to bond the fibers to each other and to other components during manufacturing. Thermosetting matrices are only partially cured to allow for easy handling, and this B-stage material requires cold storage to prevent complete curing. B-stage prepregs are always stored in a refrigerated space because heat promotes complete polymerization. Thermoplastic matrices do not require such cold storage. Therefore, composite structures assembled with prepregs often require ovens or autoclaves for curing. Prepregs allow for impregnation of fibers onto, for example, a flat surface, and then subsequent laying of the impregnated fibers to impart a desired shape, whereas laying without the matrix can otherwise be problematic.

[0053] The thermoplastic prepreg may be provided as a unidirectional tape or as a woven or sewn fabric, for example.

[0054] In one example, the first polymer composition comprises a first thermoplastic selected from the group comprising acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polycarbonate (PC), polyamide (PA), polystyrene (PS), high-density polyethylene (HDPE), PC / ABS, polyethylene terephthalate (PETG), polyphenylsulfone (PPSU), high-impact polystyrene (HIPS), polytetrafluoroethylene (PTFE), lignin, rubber, and / or polyaryletherketone (PAEK), such as polyetherketoneketone (PEKK), polyetheretherketone (PEEK), and polyetherimide (PEI). In one example, the first thermoplastic comprises, consists of, and / or is PEKK, PEEK, and / or PEI, preferably PEKK and / or PEEK, more preferably PEKK. Due to a wider range of acceptable crystallinity, PEKK is, at least in part, more resistant to (i.e., less sensitive to) cooling rates than PEEK.

[0055] In one example, the first polymer composition comprises a reactive thermoplastic, such as Elium®. Elium is a liquid monomer that can be processed similarly to a thermoset, but can be heat-deformed, melted, and / or welded after conversion to a thermoplastic immediately after reaction. Anionic polymerization of caprolactam (the monomer for polyamide-6, PA-6) is also suitable. Generally, reactive thermoplastics can be cured after lamination by reacting their molecules, for example, by heating and / or using a catalyst included in the first polymer composition, to provide a thermoplastic with improved mechanical properties.

[0056] In one example, the first polymer composition comprises a second thermoplastic, as described above with respect to the first thermoplastic (ie, copolymer).

[0057] In one example, the first polymer composition comprises a thermosetting plastic, such as an epoxy, benzoxazine, bismaleimide (BMI), polyimide, polyurethane, silicone, vinyl, amino, furan, phenolic, and / or cyanate ester resin, and optionally a curing agent.

[0058] Selection of a suitable first polymer composition for the reinforcing fibers is known.

[0059] In one example, the method comprises dispersing, redispersing, and / or agitating the additives included in the additive composition, e.g., by agitating using a mixer, while continuously, e.g., ultrasonically, impregnating the additive composition into and / or onto the pre-impregnated tape, to maintain dispersion, e.g., uniform dispersion, of the additive in the resin.

[0060] In one example, the method comprises modifying (i.e., varying, more usually controlling) the content of additives included in the additive composition in-line and / or in real time, thereby providing a custom pre-impregnated tape, e.g., a reel thereof.

[0061] A second aspect provides an apparatus for providing a pre-impregnated tape comprising reinforcing fibers for the manufacture of fiber-reinforced composite parts, the apparatus comprising non-uniformly impregnating an additive composition into and / or onto the tape to provide the pre-impregnated tape, wherein the additive composition comprises a resin and an additive, and wherein the tape comprises the reinforcing fibers.

[0062] The pre-impregnated tape, reinforcing fiber, fiber reinforced composite part, depositing, additives, and / or resin may be as described for the first embodiment.

[0063] In one example, the apparatus comprises a set of nozzles including a first nozzle as described for the first embodiment.

[0064] In one example, the apparatus comprises a means for dispersing the additives in the resin (liquid / gas nozzles, hoppers, and / or agitators, electrostatically / magnetically charged, or otherwise, e.g., resonant acoustic mixing, etc.).

[0065] A third aspect provides a pre-impregnated tape comprising reinforcing fibres having additives deposited non-uniformly in and / or on them, e.g. provided according to the method of the first aspect and / or using an apparatus according to the second aspect.

[0066] The pre-impregnated tape, reinforcing fibers, fiber reinforced composite part, depositing, and / or additives may be as described for the first embodiment.

[0067] A fourth aspect is a method for manufacturing a fiber-reinforced composite part, for example an aircraft composite part, such as an airframe or part thereof, comprising: providing a first fiber reinforced composite part; and providing a second fiber reinforced composite part, wherein the first fiber reinforced composite part and the second fiber reinforced composite part have different properties, such as electrical properties, thermal properties, magnetic properties, and / or structural properties; joining a first fiber-reinforced composite component and a second fiber-reinforced composite component; transitioning between the first fiber reinforced composite part and said second fiber reinforced composite part, e.g. provided according to the method of the first aspect and / or using an apparatus according to the second aspect and / or using a pre-impregnated tape according to the third aspect; The present invention provides a method comprising:

[0068] It is known to provide a first fiber-reinforced composite component and to provide a second fiber-reinforced composite component, and it is known to join the first fiber-reinforced composite component and the second fiber-reinforced composite component.

[0069] In one example, joining the first fiber reinforced composite component and the second fiber reinforced composite component comprises joining the first fiber reinforced composite component and the second fiber reinforced composite component at least in part using a pre-impregnated tape.

[0070] A fifth aspect provides a fibre-reinforced composite part, for example an aircraft composite part such as an airframe or part thereof, comprising a pre-impregnated tape according to the third aspect and / or manufactured according to the fourth aspect.

[0071] Embodiments of the present invention will now be described, by way of example only, with reference to the following figures. [Brief explanation of the drawings]

[0072] [Figure 1] (a) Schematic illustration of the method according to an exemplary embodiment, (b) A more detailed illustration of the method. [Figure 2] (a)-(d) Schematic representations of additive particle content of pre-impregnated tapes according to exemplary embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0073] FIG. 1(a) illustrates a schematic diagram of a method according to an exemplary embodiment.

[0074] The method provides a pre-impregnated tape 15 for the manufacture of a fiber-reinforced composite part, comprising non-uniformly impregnating 14 an additive composition into and / or onto a tape 13 comprising reinforcing fibers 11 to provide the pre-impregnated tape 15, wherein the additive composition comprises a resin and an additive.

[0075] More specifically, the present invention varies the additive concentration, functionality, or otherwise introduced into the impregnated resin using a differential impregnation unit 14. The present invention allows rolls of pre-impregnated tape to be produced with additive gradients across both the width and length of the spooled prepreg material, taking into account the ratio of resin to functional masterbatch, as can be seen in Figure 1(b).

[0076] The tow of reinforcing fibers 11 spooled onto spool 10 is processed through a spreading unit 12 as is typical in standard prepreg technology, but the concentration of additive or functional filler is controlled by a flow ratio F of pure resin R to additive or functional masterbatch resin MB, respectively. R and F MB This is changed by changing the ratio of

[0077] More specifically, Figure 1(b) shows details of the differential impregnation unit 14. The concentration of the functional masterbatch MB, and therefore the conductivity, is determined by, for example, the flow ratio F of resin R to masterbatch MB. R and F MB The mechanical properties of the tape are controlled through the change in the mechanical properties of the tape, allowing for mechanical control of the function throughout the spooled material. In this example, a pre-impregnated tape 15 is spooled onto a spool 16.

[0078] 2(a) through 2(d) are schematic illustrations of additive particle content in tapes according to exemplary embodiments.

[0079] Figure 2(a) shows a schematic representation of the additive particle content of the pre-impregnated tape 15 decreasing linearly across the width of the pre-impregnated tape. In this example, the flow rate F R and F MB is linearly varied across the width of tape 13 by differential impregnation unit 14. In this example, non-uniform impregnation of the additive composition into and / or on the tape is achieved by varying the flow rate ratio F across the width of tape 13.R and F MB and controlling the flow rates of the masterbatch and / or the additional resin by linearly varying each of the

[0080] Figure 2(b) shows a schematic representation of the additive particle content of the pre-impregnated tape decreasing non-linearly across the width of the pre-impregnated tape. In this example, the flow rate ratio F R and F MB is non-linearly varied across the width of tape 13 by differential impregnation unit 14. In this example, non-uniform impregnation of the additive composition into and / or on the tape is achieved by varying the flow rate ratio F across the width of tape 13. R and F MB and controlling the flow rates of the masterbatch and / or the additional resin by non-linearly varying each of the

[0081] Figure 2(c) shows a schematic representation of the additive particle content of the pre-impregnated tape, which varies periodically across the width of the pre-impregnated tape. In this example, the flow ratio F R and F MB is periodically varied across the width of tape 13 by differential impregnation unit 14. In this example, non-uniform impregnation of the additive composition into and / or on the tape is achieved by varying the flow rate ratio F across the width of tape 13. R and F MB and periodically changing each of the masterbatch and / or further resin to control the flow rates of each of the masterbatch and / or further resin.

[0082] Figure 2(d) shows a schematic representation of the additive particle content of the pre-impregnated tape varying non-periodically across the width of the pre-impregnated tape. In this example, the flow ratio F R and F MB is non-periodically varied across the width of tape 13 by differential impregnation unit 14. In this example, non-uniform impregnation of the additive composition in and / or on the tape is achieved by varying the flow rate ratio F across the width of tape 13.R and F MB aperiodically changing each of the masterbatch and / or the additional resin to control the flow rates of each of the masterbatch and / or the additional resin.

Claims

1. 1. A method for providing a pre-impregnated tape for the manufacture of fiber reinforced composite parts, comprising:

1. A method comprising: non-uniformly impregnating an additive composition into and / or onto a tape to provide the pre-impregnated tape, wherein the additive composition comprises a resin and an additive, and wherein the tape comprises reinforcing fibers.

2. The method of claim 1 , wherein the additive is an electrically conductive particle.

3. 3. The method of claim 1 or 2, wherein the reinforcing fibers are electrically insulating reinforcing fibers.

4. 4. The method of claim 1, wherein the tape comprises aligned reinforcing fibers and / or continuous reinforcing fibers.

5. 5. The method of any one of claims 1 to 4, wherein non-uniformly impregnating the additive composition into and / or on the tape comprises differentially impregnating the additive composition into and / or on the tape.

6. 6. The method of any one of claims 1 to 5, wherein non-uniformly impregnating the additive composition into and / or onto the tape comprises non-uniformly impregnating the additive composition into and / or onto the tape across its width and / or along its length.

7. 7. The method of claim 1, comprising providing the tape by spreading one or more tows comprising the reinforcing fibers.

8. 8. The method of claim 1, comprising using a masterbatch comprising the additive and / or a further resin to control the content of the additive in the additive composition.

9. 9. The method of claim 8, wherein controlling the content of the additive in the additive composition comprises controlling the respective flow rates of the masterbatch and / or the further resin by varying the respective flow rates of the masterbatch and / or the further resin linearly, non-linearly, periodically, and / or aperiodically across the width and / or along the length of the tape.

10. 10. The method of any one of claims 1 to 9, wherein non-uniformly impregnating the additive composition into and / or onto the tape comprises impregnating the additive composition via a set of nozzles including a first nozzle.

11. 11. The method of claim 10, wherein the set of nozzles includes a second nozzle, and wherein impregnating the additive composition via the set of nozzles including the first nozzle and the second nozzle comprises impregnating a first additive composition having a first content of the additive via the first nozzle and impregnating a second additive composition having a second content of the additive via the second nozzle, wherein the first content of the additive and the second content of the additive are different from one another.

12. 12. The method of claim 10 or 11, wherein impregnating the additive composition including the additive via the set of nozzles including the first nozzle comprises moving the first nozzle relative to the tape.

13. 13. The method of any one of claims 1 to 12, comprising spooling the pre-impregnated tape.

14. 14. The method of any one of claims 1 to 13, comprising reacting and / or functionalizing the additive.

15. 1. An apparatus for providing a pre-impregnated tape for the manufacture of fiber-reinforced composite parts, comprising: an apparatus comprising: means for non-uniformly impregnating an additive composition into and / or onto a tape comprising reinforcing fibers to provide said pre-impregnated tape, wherein said additive composition comprises a resin and an additive.

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