Fiber Reinforced Thermoplastic Composites

Abstract

The present invention relates to a fiber reinforced thermoplastic composite, in particular a fiber reinforced polyamide tape.Furthermore, the present invention relates to a method for preparing said fiber reinforced thermoplastic composite and to articles, in particular laminates, made with the thermoplastic polymer fiber reinforced thermoplastic composite of the present invention.

Description

[Background technology]

[0001] Composites can include fibers dispersed in a resin / polymer matrix. Such composites are useful in a variety of industries, such as, for example, the consumer electronics, ballistics, aerospace, and transportation industries. UD composites are composites with fibers that run substantially in one direction. UD composites with anisotropic properties can be used to create manufactured articles with properties that vary in one or more directions or dimensions.

[0002] An example of a UD composite is a UD tape or prepreg, which can be characterized as a strip or band of continuous UD fibers (e.g., glass fiber, carbon fiber, etc.) impregnated with a thermoplastic or thermosetting polymer resin. Such UD tapes can have widths of 1 to 15 cm, possibly wider (e.g., 50 cm or even 1 m), and thicknesses of less than 1 mm. Such UD tapes may be provided on a spool or reel.

[0003] In theory, all fibers in a UD composite should be uniform, parallel, and continuous. However, in practice, such properties are difficult to achieve. For example, commonly available UD tapes can have fiber regions or layers that contain non-uniform arrangements of fibers, air pockets or voids, broken fibers, etc. Many attempts have been made to address these problems.

[0004] Some attempts to solve these problems include the use of fiber spreading devices and / or the use of impregnation devices. A typical impregnation process involves the use of a bath of molten polymer through which the fiber layer can be moved. In such a process, the molten polymer may be forced into the fiber layer using rollers. Another process impregnates the fiber layer by forcing a polymer film on both sides of the layer into the layer. Each of these processes is similar in that it involves forcing a polymer resin material into the fiber layer to achieve impregnation of the fiber layer.

[0005] Although such fiber spreading and impregnation equipment and processes can be used to prepare UD tapes, such UD tapes still suffer from non-uniform fiber alignment and air pockets or voids in the matrix material. For example, some commercially available UD composites have fiber regions with non-uniform fiber alignment and therefore non-uniform density, as well as voids and air pockets in the polymer matrix.

[0006] Therefore, a need remains to provide a UD composite that overcomes the above-mentioned shortcomings of the prior art.

[0007] There is also a need to provide UD thermoplastic composites that have good impregnation of the thermoplastic matrix.

[0008] In fact, thermoplastic composites exhibit several advantages compared to the thermosetting composites (commonly used): they are recyclable, have good mechanical properties and are easier to post-process.

[0009] However, impregnation of thermosetting matrices is easier due to their low molecular weight, which is not the case for thermoplastic matrices.

[0010] Thus, there is a need for thermoplastic composites with improved impregnation of the thermoplastic matrix. Summary of the Invention

[0011] The present invention relates generally to unidirectional (UD) fiber reinforced thermoplastic composites and methods for making same.

[0012] The present inventors have surprisingly found that a matrix material comprising a thermoplastic material; a plurality of continuous fibers dispersed in a matrix material; each of the plurality of continuous fibers being substantially aligned with a length of the fiber reinforced composite; The matrix material is a relative viscosity of 1.7 to 2.3 (measured in accordance with standard DIN EN ISO 307:2019-11 at 25 °C with 96% H2SO4, 1 g of polyamide per 100 ml of H2SO4), and · Concentration of amine end groups (AEG) and carboxylic acid end groups (CEG) such that the absolute difference |AEG-CEG| is at least 50 meq / kg. It has been found that this object can be achieved by providing a fiber reinforced thermoplastic composite, the fiber being a linear or branched polyamide having the formula:

[0013] The present invention also provides methods of making fiber reinforced thermoplastic composites, and articles including fiber reinforced thermoplastic composites. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a longitudinal image of the tape according to Comparative Example 2. [Diagram 2] FIG. 2 is a longitudinal image of the tape according to Example 1. [Diagram 3] FIG. 3 is a profile image of the tape according to Example 3. [Figure 4] FIG. 4 shows a graph corresponding to the longitudinal image of the tape according to comparative example 2 (number of pixels in function of the number of grey scales). [Diagram 5] FIG. 5 shows a graph corresponding to a longitudinal image of the tape according to example 1 (number of pixels in function of the number of grey scales). [Figure 6] FIG. 6 shows a graph (number of pixels in function of grey scale number) corresponding to a longitudinal image of the tape according to example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Detailed Description Before describing the subject matter of the invention in detail, the following should be considered.

[0016] As used herein, the singular forms "a," "an," and "the" include both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a particle" means one particle or more than one particle.

[0017] The terms "comprising," "comprises," and "comprised of," as used herein, are synonymous with "including," "includes," or "containing," and are inclusive or open-ended and do not exclude additional, unrecited members, elements, or method steps. It will be understood that the terms "comprising," "comprises," and "comprised of," as used herein, include the terms "consisting of," "consists," and "consists of."

[0018] The term "voids" refers to gas pockets within a fiber-reinforced composite. The porosity of a composite can be determined by taking a cross-sectional image of the composite (e.g., using scanning electron microscopy, confocal microscopy, optical imaging, or other imaging techniques) and calculating the color difference of the fibers, matrix, and gas pockets in the cross section via grayscale analysis or color difference due to density differences.

[0019] As described above, the present invention provides a matrix material comprising a thermoplastic material; a plurality of continuous fibers dispersed in a matrix material; each of the plurality of continuous fibers being substantially aligned with a length of the fiber reinforced composite; The matrix material is a relative viscosity of 1.7 to 2.3 (measured in accordance with standard DIN EN ISO 307:2019-11 at 25 °C with 96% H2SO4, 1 g of polyamide per 100 ml of H2SO4), and The concentration of amine end groups (AEG) and carboxylic acid end groups (CEG) such that the absolute difference |AEG-CEG| is at least 50 meq / kg. The present invention relates to a fiber reinforced thermoplastic composite, wherein the polyamide is a linear or branched polyamide having the formula:

[0020] AEG and CEG are determined by potentiometric titration in trifluoroethanol (TFE) according to the protocol detailed below.

[0021] Matrix Material The matrix material is a linear or branched polyamide.

[0022] The polyamides may be selected from the group consisting of polyamides obtained by polycondensation between at least one linear aliphatic dicarboxylic acid and an aliphatic or cyclic diamine, or between at least one aromatic dicarboxylic acid and an aliphatic or aromatic diamine, polyamides obtained by polycondensation of at least one amino acid or lactam with itself, or blends and (co)polyamides thereof. Semicrystalline polyamides are particularly preferred.

[0023] In a more preferred embodiment, the polyamide is selected from the group consisting of aliphatic, cycloaliphatic or semi-aromatic polyamides and mixtures thereof.

[0024] In an even more preferred embodiment of the present invention, the polyamide is selected from the group consisting of PA6, PA10, PA11, PA12, PA6.6, PA6.9, PA4.6, PA4.10, PA5.10, PA6.10, PA6.12, PA6.14, PA10.10, PA10.12, PA10.14, PA10.18, PA12.12, PA6.18, PA6.36, PA9.T, PA6.T, PA6.I, PA10.T, PA PACM.6 (PACM=4,4-diaminodi-cyclohexylmethane), PA MPMD.10 (MPMD=methylpentamethylenediamine), MPMD.6 / MPMD.T, PA IPD.6 (IPD=isophoronediamine), blends thereof, and copolymers based on these polyamides.

[0025] Most preferably, the polyamide is selected from the group consisting of PA6.6, PA6, PA6.10, PA6.12, PA11 and PA12, copolyamides PA6.6 / 6, PA6 / 6.6, PA6 / 6.T, PA6.T / 6, PA6.10 / 6.T, PA6.6 / 6.T, PA6.T / 6.6, PA6.T / 6.I, PA6.T / 6.I / 6.6, PA6.T / MPMD.T and blends thereof, such as PA6.6 / PA6, PA6.10 / PA6.6 and PA6.6 / 6.T / PA6, PA6.6, PA6, PA6.10, PA6.12, PA11 and PA12, copolyamides such as PA66 / 6 and blends of polyamides, such as PA66 / PA6, are also suitable.

[0026] The polyamide is preferably PA6.

[0027] The matrix material is preferably a branched polyamide.

[0028] According to one preferred embodiment, the branched polyamide is a) a monomer of the following general formula (I): [ka] b) Monomers of the following general formulae (IIa) and (IIb): [ka] c) a compound represented by the following general formula (III): Z-R3-Z (III) (In the formula, R1 is a linear or cyclic, aromatic or aliphatic hydrocarbon group containing at least 2 carbon atoms and which may contain heteroatoms; A is a covalent bond or an aliphatic hydrocarbon group containing 1 to 6 carbon atoms; Z represents a primary amine group or a carboxyl group; R2 and R3 are the same or different and each is a substituted or unsubstituted aliphatic, alicyclic or aromatic hydrocarbon group containing 2 to 20 carbon atoms and which may contain a heteroatom; X represents a carboxyl group or a primary amine group, and when X represents a carboxyl group, Y is a primary amine group, or when X represents a primary amine group, Y is a carboxyl group; m is an integer ranging from 3 to 8; The molar concentration of the monomers of formula (I) in the mixture of monomers is 0.01% to 1%, the remainder is 100%, which corresponds to the monomers of general formulae (IIa) and (IIb). It is a polyamide which can be produced by a process for the polycondensation of a mixture of monomers comprising:

[0029] Preferably, the molar concentration of the monomer of formula (III) is between 0.1 and 2%, the remaining 100% being made up of the monomer of formula (IIa) or (IIb).

[0030] The monomers of general formula (I) contain a group R1 which is a trivalent group of phenyl or cyclohexanyl type, which may be substituted or not, a tetravalent diaminopolymethylene group advantageously having 2 to 12 methylene groups (for example a group derived from EDTA (ethylenediaminetetraacetic acid)), an octavalent cyclohexanonyl or cyclohexazinonyl group, a group derived from a compound resulting from the reaction of a polyol, such as glycerol, sorbitol, mannitol or pentaerythritol, with acrylonitrile. Preferred groups R1 according to the invention are alicyclic groups, such as a tetravalent cyclohexanonyl group. The group R1 is preferably a cyclohexanoyl group.

[0031] The group A is preferably a methylene or polymethylene group, for example an ethylene, propylene or butylene group.

[0032] The letter m preferably represents an integer greater than 3 and advantageously equal to 4, 5 or 6.

[0033] According to another characteristic of the invention, the group R3 of general formula (III) represents a polymethylene group which may contain from 2 to 36 carbon atoms or an alicyclic or aromatic group.

[0034] By way of example, compounds of formula (III) may include succinic acid, adipic acid, terephthalic acid, isophthalic acid, sebacic acid, azelaic acid, dodecanoic acid or di(β-carboxyethyl)cyclohexanone. Diamine compounds such as hexamethylenediamine, 5-methylpentamethylenediamine, metaxylylenediamine, isophoronediamine or 1,4-diaminocyclohexane may also be included.

[0035] The monomers of formula (II) are advantageously lactams or amino acids, such as ε-caprolactam, lauryllactam and their ω-amino acids.

[0036] This polyamide is disclosed in WO 2011 / 039183, the contents of which are incorporated herein by reference.

[0037] The mixture of monomers preferably does not contain a monomer of formula (IV)W-R4-W, where W represents a primary amine group when Z represents a carboxyl group, W represents a carboxyl group when Z represents a primary amine group, and R4 has the same definition as R3.

[0038] According to another preferred embodiment, the branched polyamide is at least one tri- or tetrafunctional polyamine monomer containing three or four amine functional groups selected from the group consisting of a secondary amine group of formula -NH- and a primary amine group of formula -NH2 [monomer (FN)], ε-caprolactam (or its derivatives) and wherein the repeat unit is derived from the polycondensation of a mixture comprising When the monomer (FN) is a trifunctional polyamine monomer, said monomer (FN) is used in an amount such that the molar ratio monomer (FN) / ε-caprolactam (or a derivative thereof) is at least 0.002 and at most 0.030, When the monomer (FN) is a tetrafunctional polyamine monomer, said monomer (FN) is used in an amount such that the molar ratio monomer (FN) / caprolactam (or a derivative thereof) is at least 0.001 and at most 0.030, The branched polyamide has a concentration of amine end groups (AEG) and a concentration of carboxylic acid end groups (CEG) such that the difference AEG-CEG is at least 100 meq / kg and at most 300 meq / kg.

[0039] Examples of monomers (FN) include tris(aminoalkyl)amines, such as tris(2-aminoethyl)amine (TREN); polyoxyalkylene triamines, such as Jeffamine T® from Huntsman, including Jeffamine T403® (polyoxypropylene triamine); polyalkylene polyamines, such as polyethyleneimines, which may advantageously have variable molecular weights, 1,8-diamino-4-aminomethyl-octane (TAN) and dialkylene triamines, such as diethylenetriamine (DETA), bis(hexamethylene)triamine (BHT) and cyclohexane-1,3,5-triamine and 2,2,6,6-tetrakis(2-aminoethyl)cyclohexanone.

[0040] Preferred polyfunctional monomers are bis(hexamethylene)triamine (BHT), tris(2-aminoethyl)amine (TREN), 1,8-diamino-4-aminomethyl-octane (TAN) and combinations thereof.

[0041] For the production of branched polyamides, it is preferred to use ε-caprolactam.

[0042] This polyamide is disclosed in WO 2021 / 063835, the contents of which are incorporated herein by reference.

[0043] The polyamides of the present invention preferably do not contain hydroxyaromatic units chemically bonded to the polyamide chain.

[0044] The matrix material may consist of a single polyamide or a mixture of polyamides.

[0045] The matrix material of the present invention preferably has a relative viscosity of at least 1.8 and at most 2.25.

[0046] Preferably, the matrix material of the present invention has a concentration of amine end groups (AEG) and a concentration of carboxylic acid end groups (CEG)° such that the absolute difference |AEG-CEG| is at least 80 meq / kg, more preferably at least 100 meq / kg.

[0047] Preferably, the amine end groups (AEG) and the carboxylic acid end groups (CEG)° are obtained without any post-modification, in other words therefore, the amine end groups (AEG) and the carboxylic acid end groups (CEG)° are preferably amine end groups and carboxylic acid end groups obtained directly after polycondensation, for example the polycondensation described above.

[0048] Continuous Fiber The fiber reinforced composite of the present invention comprises continuous fibers. Continuous fibers means fiber bundles having a length of more than 10 cm. The average fiber length of the continuous fiber bundles used in the present invention is not particularly limited. It can be, for example, 10,000 m or 20,000 m. According to one embodiment of the present invention, a fiber roving is used that comprises an assembly of individual filaments held together.

[0049] The fiber reinforced composites of the present invention can include fibers from a plurality of fiber bundles, each bundle including from 400 to 60,000 (1000 to 60,000) individual filaments. However, a bundle can include up to 100,000 individual filaments. The fibers in the bundle can have an average filament diameter of, for example, 5 to 24 microns, 10 to 20 microns, or any range therebetween.

[0050] Non-limiting examples of continuous fibers include glass fibers, carbon fibers, aramid fibers, basalt fibers, steel fibers, metal fibers, boron fibers, ceramic fibers, or combinations thereof.

[0051] Glass fiber bundles (e.g., fiberglass yarn bundles) are commercially available from NEG (Nippon Electric Glass), Jushi Group Co., Ltd. (China), and Kripa International (India) under the tradenames HYBON® or TUFRov®. The glass fiber bundles can have an average filament diameter of, for example, 10-24 microns, 12-20 microns, or any range therebetween. Carbon fiber or modified carbon fiber bundles (e.g., carbon fiber tows) are commercially available from ACP Composites (Livermore, Calif., USA), Toray Industries, Inc. (Japan), and ZOLTEK (Bridgeton, Mo., USA) under the tradename Panex®. The carbon fiber bundles can have an average filament diameter of, for example, 3-8 microns, 6-7 microns, or any range therebetween.

[0052] Aramid fiber bundles (e.g., aramid fiber yarn bundles) are sold by DuPont (Wilmington, Del., USA) under the trade name KEVLAR®. Ceramic fiber bundles (e.g., metal oxide fiber bundles) are commercially available from 3M (USA) under the trade name 3M™ Nextel™ Continuous Ceramic Oxide Fibers. Basalt fiber bundles are commercially available from Kamenny Vek (Republic of Russian Federation) under the trade name Basfiber® or from Sudaglass Fiber Technology (Republic of Russian Federation) under the trade name Sudaglass.

[0053] Glass or carbon fibers are preferred. Glass fibers with circular or non-circular cross-sections can be used. Hollow glass fibers can also be used.

[0054] The expression "hollow glass fibre" means a "tubular" glass fibre having an outer diameter of 10-12 μm and an inner diameter of 5-6 μm.

[0055] Also, "flat glass fiber" can be used. In the present invention, the term "flat glass fiber" is intended to indicate a glass fiber having a non-circular cross section. The flat glass fiber suitable for the present invention can have any non-circular cross section, such as an elliptical cross section, an oval cross section, a rectangular cross section, a cross section in which a semicircle is connected to both short sides of a rectangle, and a cocoon cross section.

[0056] The aspect ratio (=long diameter / short diameter) of the noncircular cross section of the flat glass fiber is advantageously 1.0 to 10, preferably 1.5 to 6.0, more preferably 2.0 to 5.0, and most preferably 3.0 to 4.0.

[0057] The aspect ratio according to the present invention can be determined by analyzing an image obtained by observing the cross section of the flat glass fiber with a scanning electron microscope (SEM) and circumscribing the non-circular cross section of the flat glass fiber with a rectangle. The aspect ratio can be determined by calculating A (= length of Ra) / B (= length of Rb) when the lengths of the long side Ra and short side Rb of the rectangle circumscribing the flat glass fiber in the observed image are A and B.

[0058] Furthermore, the flat glass fiber of the present invention preferably has a length of the main cross-sectional axis in the range of 6 to 40 μm, more preferably 17 to 30 μm, or 24 to 28 μm. The length of the minor cross-sectional axis is preferably in the range of 3 to 20 μm, and in the case of particles, in the range of 4 to 10 μm. The length of the main cross-sectional axis is more preferably 7 or 8 μm.

[0059] The nature of the glass constituting the glass fibers of the present invention is not particularly limited, and examples include E-glass, T-glass, NE-glass, C-glass, S-glass, S2-glass, R-glass, etc. The glass fibers may contain a sizing agent on their surface to ensure their cohesion when in continuous strand form, and to provide adhesion, especially at the interface with the polyamide matrix.

[0060] In a preferred embodiment, circular cross-section glass fibers are used.

[0061] The continuous fiber of the present invention may be treated with a treatment agent. Examples of the treatment agent include a surface treatment agent, a sizing agent, etc. The consumption of the treatment agent is preferably 0.001 to 1.5% by mass, more preferably 0.1 to 1.2% by mass, and even more preferably 0.5 to 1.1% by mass of the continuous fiber.

[0062] Examples of the surface treatment agent include functional compounds such as epoxy compounds, acrylic compounds, isocyanate compounds, silane compounds, and titanate compounds, and further examples include silane coupling agents and titanate coupling agents. Silane coupling agents are preferred.

[0063] Examples of silane coupling agents include trialkoxy- or triaryloxysilane compounds such as aminopropyltriethoxysilane, phenylaminopropyltrimethoxysilane, glycidylpropyltriethoxysilane, methacryloxypropyltrimethoxysilane, and vinyltriethoxysilane; ureidosilane; sulfidosilane; vinylsilane; and imidazole silane.

[0064] Examples of the sizing agent include epoxy resins such as bisphenol A epoxy resins; and vinyl ester resins including bisphenol A vinyl ester resins, which are epoxy acrylate resins having an acrylic group or a methacrylic group in one molecule of vinyl ester resins, novolac vinyl ester resins, and brominated vinyl ester resins. The sizing agent may be a urethane-modified resin of an epoxy resin or vinyl ester resin.

[0065] The treatment agent may be used alone or in combination of two or more kinds.

[0066] The method of treating the continuous fiber with the treatment agent can be a known method. For example, the continuous fiber can be immersed in a liquid (such as an aqueous solution) containing the treatment agent, and the treatment agent is adhered to the surface of the continuous fiber. The treatment agent can also be sprayed onto the surface of the continuous fiber by air. Alternatively, a commercially available continuous fiber that has been treated with a treatment agent can be used, or the previously applied treatment agent can be removed and then treated again with a desired amount of treatment agent for use.

[0067] Additives The polymer matrix of the fiber reinforced composite may be included in the composition along with one or more additives, non-limiting examples of which include antioxidants, heat stabilizers, flame retardants, UV stabilizers, UV absorbers, impact modifiers, pigments and colorants, processing aids, toughening agents, or combinations thereof.

[0068] Non-limiting exemplary stabilizers suitable for use as additive components in the disclosed compositions can include, but are not limited to, Irganox® B225, Irganox® 1098, Irganox® B1171, commercially available from BASF. Non-limiting examples of flame retardants include halogen and non-halogen based polymer modifiers and additives including melamine and melamine cyanurate derivatives, phosphinates and phosphonates and their salts, polyphosphates including melamine polyphosphates, which can be used in addition to synergistic systems such as Sb2O3 or Zn borate. Non-limiting examples of UV stabilizers include hindered amine light stabilizers, hydroxybenzophenones, hydroxyphenylbenzotriazoles, cyanoacrylates, oxanilides, hydroxyphenyltriazines, and combinations thereof. Non-limiting examples of UV absorbers include 4-substituted-2-hydroxybenzophenones and their derivatives, aryl salicylates, monoesters of diphenols such as resorcinol monobenzoate, 2-(2-hydroxyaryl)-benzotriazoles and their derivatives, 2-(2-hydroxyaryl)-1,3,5-triazines and their derivatives, or combinations thereof. Non-limiting examples of impact modifiers include elastomer / soft blocks dissolved in matrix-forming monomers. Non-limiting examples of pigments and colorants include TiO2, carbon black, ZnS, color pigments suitable for use in polyamide matrices. Non-limiting examples of processing aids include long chain fatty acids such as stearic acid, their esters such as isobutyl stearate, and metal salts such as Li, Na, Ca, Zn, Al stearate, stearamides such as ethylene bisstearamide, montan waxes, paraffin oils, ethylene waxes and ethylene oxide waxes, aliphatic ester waxes such as Barolub LT107® from Barlocher. Non-limiting examples of enhancers include: - Polyolefins and copolyolefins (ethylene, propylene, octene, butene, butadiene, etc.), copolymerized or grafted with: Carboxylic acids (e.g. acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, etc.). Anhydrides: e.g. maleic anhydride, itaconic anhydride.

[0069] For example, EP (ethylene / propylene)-g (grafted)-MA (maleic anhydride) and EPDM (ethylene / propylene / diene)-g (grafted)-MA (maleic anhydride) rubbers, e.g. Exxelor® from Exxon - such as Exxelor® VA1801 or Exxelor® VA1803 - or Fusabond® from Dow, such as Fusabond® N493. Carboxylate salts: for example, Na+, Li+, Ca++, Zn++, Al+++ salts of carboxylic acids. For example, "ionomers" such as Surlyn® ionomers from EI DuPont de Nemours & Co. Esters: for example methyl, ethyl, butyl, glycidyl acrylate or methacrylate, optionally copolymerized with maleic anhydride (for example Lotader® from Arkema / SK® or Bynel® from Dow), and vinyl esters (for example EVA copolymers under the trade name Elvax® from Dow). Styrene-butadiene copolymers, including SBR rubber (styrene-butadiene), SB (styrene-butadiene) and SBS (styrene-butadiene-styrene) rubbers, also in hydrogenated form (e.g. SEBS-styrene-ethylene / butene-styrene-rubbers), are copolymerized or grafted with carboxylic acids (e.g. acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, etc.) or anhydrides, such as maleic anhydride, itaconic anhydride (e.g. Kraton G® from Kraton corporation, which grafts maleic anhydride to SEBS block copolymers).

[0070] The heat stabilizer is preferably a stabilizer containing copper. It may be a mixture of an alkali metal or alkaline earth metal halide and a copper compound. The copper compound is preferably selected from the group consisting of copper(I) oxide, copper(II) oxide, copper(I) or copper(II) salts, such as copper(I) or copper(II) acetate, copper(I) or copper(II) acetate, copper(I) or copper(II) stearate, copper(I) or copper(II) organic complex compounds such as copper acetylacetonate, copper(I) or copper(II) halide, and the like. According to a particular preferred embodiment, the copper-containing stabilizer is essentially composed of a copper halide selected from copper iodide and copper bromide, and the alkali metal halide is preferably selected from the iodides and bromides of lithium, sodium and potassium.

[0071] A particularly preferred combination is the combination of CuI and KI. Another very advantageous combination is a mixture of Cu2O and KBr.

[0072] The amount of copper (Cu) in the copper-containing stabilizer is generally sufficient to provide a copper level in the fiber reinforced composite of from about 25 to about 1000 ppm, preferably from about 50 to about 500 ppm, and more preferably from about 75 to about 200 ppm.

[0073] The amount of halide-containing (I or Br) stabilizer is generally sufficient to provide a level of halide in the fiber reinforced composite of from about 100 to about 5000 ppm, preferably from about 300 to about 3000 ppm, and more preferably from about 500 to about 2000 ppm.

[0074] Preferably, the fiber reinforced composite of the present invention may contain 10-70% by weight, preferably 20-60% by weight, more preferably 20-50% by weight, even more preferably 20-40% by weight of matrix material.

[0075] Preferably, the fiber reinforced composite of the present invention may contain 30 to 90% by weight, preferably 40 to 80% by weight, more preferably 45 to 80% by weight, and even more preferably 50 to 80% by weight of continuous fibers.

[0076] In a preferred embodiment, the fiber reinforced composite of the present invention comprises: 10-70% by weight, preferably 20-60% by weight, more preferably 20-50% by weight, even more preferably 20-40% by weight of a matrix material, 30 to 90% by weight, preferably 40 to 80% by weight, more preferably 45 to 80% by weight, and even more preferably 50 to 80% by weight of continuous fibers; may include.

[0077] The fiber reinforced composite material of the present invention is 10-70% by weight, preferably 20-60% by weight, more preferably 20-50% by weight, even more preferably 20-40% by weight of a matrix material, 30 to 90% by weight, preferably 40 to 80% by weight, more preferably 45 to 80% by weight, and even more preferably 50 to 80% by weight of continuous fibers; 0 to 30% by weight, preferably 1 to 20% by weight, of an additive; may include.

[0078] The fiber reinforced composite is preferably free of novolac resin.

[0079] Generally, the weight percentages of the matrix material, continuous fiber, and additives can be based on the amounts weighed to prepare the fiber-reinforced composite. They can also be determined by other methods. The continuous fiber weight percentage can be determined, for example, from the ash content measured according to standard ISO 3451-4.

[0080] The matrix material of the invention (with the required relative viscosity and absolute difference |AEG-CEG|) makes it possible to achieve good impregnation of the continuous fibers with the matrix during the preparation of the fiber-reinforced composite.

[0081] The fiber reinforced composites of the present disclosure may contain a void volume fraction of less than 3%, preferably less than 2%.

[0082] According to a first preferred embodiment of the invention, the fiber reinforced thermoplastic composite is a monolayer tape.

[0083] The fiber reinforced thermoplastic composites of the present invention may be solid profiles having a rectangular or circular cross section, such as rods.

[0084] The fiber reinforced thermoplastic composites of the present disclosure can be used in a variety of articles of manufacture.

[0085] In a preferred embodiment, the fiber reinforced composite of the present invention comprises: 20 to 60% by weight, preferably 20 to 50% by weight, more preferably 20 to 40% by weight of a matrix material; 40-80% by weight, preferably 45-80% by weight, more preferably 50-80% by weight, of continuous fibers selected from the group consisting of glass fibers, carbon fibers, aramid fibers, basalt fibers, steel fibers, metal fibers, boron fibers, ceramic fibers or combinations thereof; 1 to 20% by weight of an additive, The matrix material is the concentration of amine end groups (AEG) and carboxylic acid end groups (CEG) such that the absolute difference |AEG-CEG| is at least 100 meq / kg; -Relative viscosity is between 1.8 and 2.25.

[0086] Method for manufacturing fiber-reinforced thermoplastic composites The present invention also relates to a method for producing a fiber reinforced thermoplastic composite, in particular a monolayer tape, according to the invention, comprising the steps of: unwinding one or more fiber bundles, each having a plurality of fibers, from one or more spools; preparing one or more fiber bundles for spreading; - spreading or flattening one or more fiber bundles into a spread layer; impregnating the fiber layer with the matrix material by wetting the layer with the matrix material and incorporating the layer into the matrix material to form a fiber reinforced composite; forming the fiber reinforced composite into a tape; winding the tape onto a spool; The present invention relates to a method, including

[0087] The process of the present invention can be implemented with a spool of fiber bundle, an unwinding unit, a fiber preparation section, a spreading section, an impregnation section, a forming unit, and a winder. The spool of fiber bundle can be disposed on an unwinding unit that can unwind the fiber bundle from the spool so that the fiber bundle can be provided to the fiber preparation section. The fiber preparation section can include units known in the art for preparing the fiber bundle for spreading. For example, the fiber preparation section can include one or more tensioners (e.g., a dancer tension control system, one or more rollers, etc.) for tensioning, stabilizing, and possibly guiding the fiber bundle. Such tensioners can provide tension to the fiber bundle while in contact with the spreading element and can help to maintain the fiber bundle in place while spreading or flattening the fiber bundle. In some cases, the unwinding unit can be spaced (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 m or more) from the fiber preparation section and / or the spreading section, for example, so that the weight of the fiber bundle helps to play a role in providing tension to the fiber bundle. As a further example, the fiber preparation section may be configured to heat the fiber bundle and / or spray the fiber bundle (e.g., to remove any coating that may be present on the fiber bundle).

[0088] In the spreading section, the fiber bundles may be spread or flattened into a spread fiber layer. The spread fiber layer may be provided to an impregnation section where the fiber layer may be wetted with and incorporated into a matrix material to form a fiber reinforced thermoplastic composite. The impregnation section may include an extruder, a bath, a coating system, etc. The fiber reinforced thermoplastic composite may enter a molding unit where the fiber reinforced thermoplastic composite may be formed into a tape or sheet. The tape may be provided to a winder, which may wrap the tape around a spool (e.g., to facilitate storage, transportation, etc. of the tape).

[0089] The process of the present invention implements a spreading unit configured to spread one or more fiber bundles, each having a plurality of fibers, into a spread fiber layer. The fiber bundles can be spread in a direction perpendicular to the length dimension of the fiber bundle, thereby forming a spread or flattened fiber layer.

[0090] The terms "flattened" and "spread out" are synonymous in this application. As used in this disclosure, "flattened," "flattening," "spread out," and "spreading" may each be used in reference to a process of spreading a fiber bundle laterally, or in a direction substantially perpendicular to the long dimension of the fiber bundle, such that the fiber bundle is narrowed when viewed from the side.

[0091] More generally, any desired number of fiber bundles can be introduced into the UD tape production line. Fibers from the fiber bundles are continuously pulled through the production line by a pulling unit located at the end of the production line. The produced UD tape is wound onto a spool.

[0092] The fibre reinforced thermoplastic composites of the present disclosure may be produced at speeds of 1 to 50 m / min, preferably 2 to 25 m / min, more preferably 2 to 12 m / min, and even more preferably 4 to 12 m / min.

[0093] The matrix material of the present invention (with the required relative viscosity and absolute difference |AEG-CEG|) makes it possible to produce tapes with stable processes and good processability.

[0094] Goods The fibre reinforced thermoplastic composites can for example have widths of 1 mm to 1000 mm or 2 mm to 1000 mm and up to 2000 mm.

[0095] Laminates including the fiber reinforced thermoplastic composites of the present disclosure are also disclosed. Such laminates can include 2, 3, 4, 5, 6, 7, 8, 9, 10 or more plies, and one ply can consist of one fiber reinforced thermoplastic composite of the present disclosure. In some laminates, at least two plies are arranged such that their respective fibers are substantially parallel to a first axis. In some laminates, at least two plies are arranged such that their respective fibers are not parallel to each other. The fiber reinforced thermoplastic composites and laminates of the present disclosure can be assembled or processed into two-dimensional or three-dimensional structures, for example, via wrapping and / or lay-up techniques.

[0096] The composites, plies, stacks and laminates may be provided with a protective coating.

[0097] Also disclosed are articles of manufacture comprising any of the fiber reinforced thermoplastic composites or laminates of the present disclosure. Non-limiting examples of such articles of manufacture include automotive parts (e.g., doors, hoods, bumpers, A-beams, B-beams, battery casings, white bodies, stiffeners, cross beams, seat structures, suspension components, hoses, etc.), braided structures, woven structures, filament wound structures (e.g., pipes, pressure vessels, etc.), aircraft parts (e.g., wings, bodies, tails, stabilizers, and / or the like), wind turbine blades, boat hulls, boat decks, railroad cars, sporting goods, window profiles, pilings, docks, reinforced wood beams, improved concrete structures, reinforced extrusions or injection moldings, hard disk drive (HDD) or solid state drive (SSD) casings, TV frames, smartphone mid-frames, smartphone single body casings, tablet mid-frames, tablet single body casings, TV stands or tables, laptop computer casings, exteriors, plates, etc.

[0098] This invention is further illustrated by the following examples, which should not be construed in a limiting sense.

[0099] analysis The relative viscosity (RV) was determined for 1 g of polyamide per 100 ml of H2SO4 at 25 °C in 96% H2SO4 according to the DIN EN ISO 307:2019-11 standard.

[0100] Carboxylic acid end group (CEG) and amine end group (AEG) concentrations were determined by potentiometric titration in trifluoroethanol (TFE) solvent (unit: meq / kg).

[0101] Grayscale Analysis This analysis is applicable to tapes containing glass fibre and natural colour polyamide 6 based matrix.

[0102] A color photograph of the tape (longitudinal direction) is taken with a scanner Epson Perfection V850 Pro. The image analysis software "ImageJ" converts the photograph from the scanner into an image based on 8-bit color (8 bits per pixel), which allows recording 256 different intensities (i.e. shades of gray).

[0103] A grayscale image is an image in which the value of each pixel is a single sample representing only the amount of light; that is, it conveys only intensity information. A grayscale image is a type of black-and-white or gray monochrome, consisting only of shades of gray. Contrast ranges from the weakest intensity of black to the strongest intensity of white.

[0104] The images are then analyzed using the image analysis software "ImageJ." The grayscale number of each pixel in the image is determined (from 0 - black - to 255 - white -).

[0105] An average greyscale number is calculated, which corresponds to the average of the individual greyscale numbers of each pixel in the image.

[0106] The higher this average, the more translucent the material and the better the impregnation of the fibers into the matrix.

[0107] Measurement method for porosity of fiber-reinforced composites by grayscale analysis The method is applicable to tapes containing glass fibre and a natural colour polyamide 6 based matrix.

[0108] The gaps correspond to the individual grayscale numbers of the photograph, which range from 0 to 30 according to the grayscale analysis described above.

[0109] The porosity corresponds to the percentage of each grayscale number in the photograph, which ranges from 0 to 30.

[0110] Method for measuring porosity of fiber-reinforced composite materials The porosity of a fiber-reinforced composite can be measured in the following manner: This analysis is applicable, for example, to tapes containing carbon fibers.

[0111] A part of the fiber-reinforced composite was cut out, the obtained slice was embedded in epoxy resin, and polished so that the cross section in the thickness direction of the outer layer was exposed. The cross section was photographed using an ultra-deep color 3D profile microscope VK-9500 (controller unit) / VK-9510 (measurement unit) (manufactured by Keyence Corporation). From the obtained cross-sectional image, the void area was selected using the image analysis software "ImageJ" and the area was measured. Using this measurement value, (area of ​​the void area appearing in the cross section of the fiber-reinforced composite / cross-sectional area of ​​the fiber-reinforced composite) x 100 was calculated. For all fiber-reinforced composites, three points were measured, the average value was taken, and the void ratio (unit: %) was calculated by rounding off the decimal point.

[0112] The tensile strength and tensile modulus of the laminates were determined in accordance with standard DIN EN ISO 527-5:2010-01. The dimensions of the test specimens are as follows: Measurement in 0° direction: length 250mm, width 15mm, thickness 1mm Measurements at 90°: length 250mm, width 25mm, thickness 2mm

[0113] The specimens are dried at 80°C for 24 hours before testing.

[0114] To test the tensile strength and tensile modulus of the tape, the dimensions of the specimen are the same as above, except for the thickness, which corresponds to the thickness of the tape. The specimens "held in an envelope / recipient that prevents moisture uptake" are conditioned at 50% relative humidity and 23°C for approximately 72 hours prior to testing.

[0115] The flexural strength and flexural modulus of the laminates were determined according to standard DIN EN ISO 14125:2011-05.

[0116] The dimensions of the test specimen are 60 mm in length, 15 mm in width, and 2 mm in thickness.

[0117] material Matrix Material - Domamid® H22 is a linear polyamide 6 from Domo Chemicals, having the following characteristics: RV:2.2 AEG(meq / kg):40 CEG(meq / kg):70 Absolute |AEG-CEG|(meq / kg):30 - Domamid® H24 is a linear polyamide 6 from Domo Chemicals, having the following characteristics: RV:2.4 AEG(meq / kg):40 CEG(meq / kg):70 Absolute |AEG-CEG|(meq / kg):30 -Domamid H1220 AEG 101 is a linear polyamide 6 with the following properties: RV:2.2 AEG(meq / kg):130 CEG(meq / kg):25 Absolute|AEG-CEG|(meq / kg):105

[0118] -Technylstar This branched polyamide is obtained by the following process.

[0119] The polymerization is carried out in a heated autoclave containing a means of stirring. Caprolactam and 2,2,6,6-tetra(β-carboxyethyl)cyclohexanone (known as T4) are added to the autoclave along with distilled water and adipic acid (known as T2).

[0120] The cyclohexanone derivative (T4) and its synthesis process are described in the article "The Chemistry of Acrylonitrile II-Reactions with Ketones" by Herman Alexander Bruson and Thomas W. Riener, JACS, 64, 2850 (1942).

[0121] The stirred mixture (containing 96,618 wt. % caprolactam, 0.697 wt. % T4 and 0.393 wt. % T2) is heated to a temperature of 265° C., a pressure of 1.45 bar is reached, and the mixture is maintained at this temperature and pressure for 5 h and 25 h. The pressure is then reduced to 0.5 bar within 1.5 h.

[0122] The results and properties of the resulting polyamide are summarized below. RV:2.157 AEG(meq / kg):20 CEG(meq / kg):160 Absolute |AEG-CEG|(meq / kg):140

[0123] -Staramine This branched polyamide was synthesized in a stainless steel clave equipped with a mechanical stirrer by polymerizing e-caprolactam in the presence of bis(hexamethylene)triamine, water (30% wt) in the following molar ratio: n(bis(hexamethylene)triamine) / n(e-caprolactam)=0.0042. The mixture was gradually heated to 245° C. under 17.5 bar, allowing the distillation of water. The pressure was then gradually removed to atmospheric pressure. The pressure was then gradually set to 500 mbar in 45 min, and the temperature was maintained at 245° C. The vacuum was then broken and the polymer was extruded, cooled in a water bath and pelletized. Removal of oligomers was performed by washing several times in hot water so that the residual content of caprolactam was less than 0.3% by weight. Finally, the pellets were dried before analysis.

[0124] This branched polyamide had the following characteristics: Mn=12700g / mol, IP=1.7. Melting temperature Tm=221°C.

[0125] This branched polyamide has the following characteristics: RV:2.08 AEG(meq / kg):153 CEG(meq / kg):35 Absolute|AEG-CEG|(meq / kg):118

[0126] The number average molecular weight (Mn) and dispersity index (IP) are determined by one skilled in the art using formulas (I) and (II).

number

[0127] Continuous Fiber TUFRov® 4510 2400tex is E-glass fiber roving from NEG TUFRov® 4510 1200tex is E-glass fiber roving from NEG

[0128] These glass fibre rovings have a fibre diameter of 17 microns with silane sizing compatible with nylon and have a tex of 1200 or 2400 g / km.

[0129] Additives PA6-based masterbatch KNF / 2 containing: -PA6 as matrix -Masterbatch 0, >1 wt% CuI and KI in >1 wt% calcium stearate -KNF / 2 is premixed with the polymer to achieve 2, 5 wt% in the final blend with glass fibers.

[0130] Process for manufacturing the tape A pultrusion line for UD tapes is used.

[0131] The processing line includes a creel for bobbins with endless fibers, which is adjustable to set a defined tension on the fibers (600cN for TUFRov® 4510 2400tex, 300cN for TUFRov® 4510 1200tex).

[0132] The line has a spreading unit with a spreading rod heated at 150°C.

[0133] A pultrusion chamber with 8-12 waves is used for impregnation. This chamber has a width of 80 mm and a length of 500 mm, and the matrix material (after being dry blended with the masterbatch additives) enters the chamber (whose temperature is 300°C) at four points. The feeding of the chamber with the matrix material (including the additive masterbatch) is done by a single screw extruder (extruder temperatures 250°C / 270°C / 280°C / 300°C).

[0134] A water-cooled calendar is used to finish the surface.

[0135] The tensioning and winding units pull the material at a defined speed (at 6 m / min) for all comparative and inventive examples, except for Example 4, where the speed is 10 m / min.

[0136] The edges of the tape are cut off in a cutting unit to finish the material.

[0137] Table 1 shows the composition of the tapes (numbers correspond to weight percentages).

[0138] [Table 1]

[0139] Table 2 shows the results regarding the tape properties and processability during tape manufacture.

[0140] [Table 2]

[0141] The processability of the materials was evaluated when they were processed through the pultrusion impregnation equipment as explained above. If the material could be continuously and stably processed with minimal or no non-uniformity defects such as dry fibers / poor impregnation zones resulting in poor quality and possible machine stoppages, and if the final product could be obtained at the end of the process, the material was considered "processable". However, if the material could not be continuously and stably processed due to too many non-uniformities such as dry fibers / poor impregnation zones with multiple / frequent shutdowns, the material was considered "unprocessable".

[0142] The material of Comparative Example 1 was deemed "unworkable" because insufficient impregnation resulted in dry fibers that could cause the pultrusion impregnation equipment to stop, plug the equipment, or cause fiber breakage. In such a condition, no finished product could be obtained.

[0143] The material of Comparative Example 2 was considered "processable". However, many irregularities were observed, such as dry fiber patches (areas that were not fully impregnated). Furthermore, the material was not processable at speeds greater than 6 m / min and was not processable at fiber contents greater than 66 wt%.

[0144] Less non-uniformity was observed in Example 1 than in Comparative Example 2. Furthermore, in Examples 1, 2, 3, and 5, the material was still processable at speeds above 6 m / min (see Example 4), which was carried out at 10 m / min, and had a higher fiber content (see Example 6), which had 73.1% glass fibers.

[0145] In conclusion, the processability of the materials obtained in Examples 1, 2, 3, 4, 5 and 6 was much better than that of Comparative Example 2 and Comparative Example 1.

[0146] Process for manufacturing the laminate Preparation of samples for mechanical testing is carried out in a number of sheets corresponding to the specimen dimensions for the test.

[0147] The sheets are laminated under a continuous press (KFK-E laminator from Maschinenfabrik Herbert Meyer GmbH) under the following conditions: Press temperature: 250℃ Speed: 1m / min.

[0148] Table 3 shows the results regarding the properties of the laminate.

[0149] [Table 3]

Claims

1. A fiber reinforced thermoplastic composite, a matrix material comprising a thermoplastic material; a plurality of continuous fibers dispersed in the matrix material; each of the plurality of continuous fibers being substantially aligned with the length of the fiber-reinforced composite; The matrix material is Relative viscosity of 1.7 to 2.3 (at 96% H at 25°C according to standard DIN EN ISO 307:2019-11) ２ SO ４ , 100ml of H ２ SO ４ (measured in 1 g of polyamide per 1 g of polyamide), and The concentration of amine end groups (AEG) and the concentration of carboxylic acid end groups (CEG) such that the absolute difference |AEG-CEG| is at least 100 meq / kg. A fiber reinforced thermoplastic composite, which is a linear or branched polyamide having the formula:

2. The fiber-reinforced thermoplastic composite according to claim 1, wherein the relative viscosity is 1.8 or more and 2.25 or less.

3. The fiber reinforced thermoplastic composite material is 10 to 70 wt. % of a matrix material; 30 to 90% by weight of continuous fibers; 0 to 30 wt. % of an additive; The fiber reinforced thermoplastic composite of claim 1 or 2, comprising:

4. 3. The fiber-reinforced thermoplastic composite of claim 1 or 2, which is a single-layer tape.

5. 3. The fiber-reinforced thermoplastic composite according to claim 1 or 2, which is a rod.

6. The method for producing a fiber-reinforced thermoplastic composite according to claim 4, unwinding one or more fiber bundles from one or more spools, each having a plurality of fibers; preparing the one or more fiber bundles for spreading; spreading or flattening the one or more fiber bundles into a spread layer; impregnating the fiber layer with the matrix material by wetting the layer with the matrix and incorporating the layer into the matrix material to form a fiber reinforced composite; forming the fiber reinforced composite into a tape; winding the tape onto a spool; A method comprising:

7. A fiber reinforced thermoplastic composite obtainable by the method of claim 6.

8. A laminate comprising at least the monolayer tape according to claim 4.

9. An article comprising the fiber reinforced thermoplastic composite of claim 1 or 2.

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