Thermoplastic composite material

Abstract

An aggregate of particles produced from a thermoplastic composition containing at least one semi-aromatic polyamide, wherein the volume-based median particle size D(v,0.5) is from 0.1 to 50.0 μm and the aggregate of particles has an asymmetric particle size distribution, is provided. The aggregate of particles is suitable for the production of a composite material containing continuous fibers by a slurry impregnation process.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority based on U.S. Provisional Patent Application No. 63 / 391,349, filed on July 22, 2022, and European Patent Application No. 22191834.5, filed on August 24, 2022, both of which are hereby incorporated by reference in their entirety for all purposes.

[0002] The present invention relates to a thermoplastic composite material tape comprising a semi - aromatic polyamide and continuous fibers, as well as semi - aromatic polyamide particles and a composition for producing said tape.

Background Art

[0003] Composite materials containing structural reinforcing fibers embedded in a polymer matrix are used in a variety of applications. For example, composite materials containing continuous fibers have been used to form fiber - reinforced composite material tapes, ribbons, rods, prepregs, laminates, and profiles that are useful as lightweight structural reinforcement parts in many applications. Composite materials containing a thermoplastic polymer matrix are known to offer many advantages compared to materials based on thermosetting ones. For example, a thermoplastic tape or prepreg can be processed into an article more quickly. Another advantage is that thermoplastic articles can be recycled.

[0004] Thermoplastic composite materials containing continuous fibers can generally be produced by impregnating continuous fibers, typically carbon fibers or glass fibers, using one of two methods: melt impregnation or slurry impregnation. Melt impregnation or slurry impregnation.

[0005] In melt impregnation, a conventional melt processing apparatus is used in combination with a special die, which functions to mix the molten polymer with the fibers and ensure uniform distribution of the polymer within the spread fibers. This method has the drawback that it is difficult to uniformly heat the molten mixture of the thermoplastic polymer from within the die to the core of the material at the die exit, resulting in variations in the quality of the impregnation. Furthermore, the temperature difference existing between the fibers and the molten mixture of the polymer at the level of the impregnation die also varies the quality and uniformity of the impregnation. In addition, in this method of impregnation from the melt, particularly when the glass transition temperature is high, due to the high viscosity of the thermoplastic resin, it is not possible to obtain the high fiber content and high production rate required to obtain high-performance composite materials.

[0006] Slurry impregnation, although the die may still be used, differs in that the impregnation process is carried out by passing continuous fibers through an aqueous colloidal suspension in which the polymer is vigorously mixed. This suspension typically contains both polymer particles and water, and the vigorous mixing prevents sedimentation of the polymer particles.

[0007] For example, U.S. Patent No. 4,292,105 discloses a method of impregnating a fibrous fabric-based material with a plastic resin, including forming an aqueous dispersion of a powdered plastic resin in the presence of a water-soluble thickening agent, applying the dispersion to the fibrous fabric-based material to distribute the resin throughout the fibers, drying the impregnated fibrous fabric-based material to remove the water present, and heating the dried material to fuse the resin to form a matrix of the fibers. U.S. Patent No. 4,292,105 recognizes that the penetration of the powdered plastic resin between the filaments of the fibrous material can be facilitated by using particles having a size of less than 50 microns, particularly particles having a diameter close to the diameter of the filaments of the fibrous material. However, in the examples of U.S. Patent No. 4,292,105, only the use of plastic resin particles sized to pass through a 177 micron or 250 micron sieve is disclosed. U.S. Patent No. 4,292,105 does not provide an appropriate method for preparing the particles other than sieving. In addition, U.S. Patent No. 4,292,105 does not recognize the importance of using particles having a uniform distribution of particle size and / or shape in the manufacturing process of composite materials by a slurry impregnation process, and as a result, does not disclose a method for preparing the particles starting from various polymers.

[0008] Polymer particles having an appropriate size may be obtained by grinding or milling. However, the ground particles tend to be irregular, often having a jagged edge shape and a wide particle size distribution. The irregular particle shape may reduce the powder flow performance during the tape impregnation process. In addition, the powder particles with irregular shapes may result in insufficient packing efficiency after deposition and consolidation, and as a result, large gaps will be formed in the final composite tape because the powder particles are not densely packed during deposition.

[0009] The production of powders from polymers with low crystallinity, low glass transition temperature, and / or high toughness becomes even more complicated. In other words, these attributes hinder the powder production process. For example, if the ductility of the polymer in the grinding process is high, instead of the particle size becoming small, the particle shape changes (i.e., flattens). Even when using cryogenic grinding technology, which is a method of setting the grinding temperature below the glass transition temperature of the polymer to mitigate the problem of high polymer ductility, it is still difficult to achieve a small particle size distribution.

[0010] Therefore, there is still a need to provide polymer particles having an average particle size in the range of 0.1 to 50.0 microns and a regular shape, which are used in an aqueous slurry for the production of a composite material by an impregnation process. In particular, there is a need to obtain such particles produced from polymers with a low glass transition temperature and / or high toughness, for which it is difficult to obtain a small particle size by mechanical grinding because the particles tend to adhere to the grinding device.

[0011] Although semi-aromatic polyamides are polymers that can ideally provide a polymer matrix suitable for composite materials due to their excellent mechanical properties, they have the problem of being difficult to obtain in the form of a powder containing particles having the above-described limits, i.e., an average size of 0.1 to 50.0 microns and a regular shape.

[0012] In addition, semi-aromatic polyamide polymers that are partially or completely obtained from renewable resources and satisfy the above-described requirements are more desirable because they provide an environmentally friendly solution. Summary of the Invention Means for Solving the Problems

[0013] The inventors aimed to obtain a process for preparing a composite material containing a semi-aromatic polyamide using a slurry impregnation process, and discovered that a semi-aromatic polyamide powder containing particles having an average particle size, particle size distribution, and shape appropriately designed for the slurry impregnation process can be prepared using a melt extrusion process. In the process, a thermoplastic polymer and a material that is immiscible with the thermoplastic polymer but generally soluble in a predetermined solvent are typically mixed in an extruder at a temperature higher than the melting point or softening temperature of the thermoplastic polymer and at a shear rate high enough to disperse the thermoplastic polymer in the immiscible material; then, the molten mixture is cooled to below the melting point or softening temperature of the thermoplastic polymer to form solidified particles containing the thermoplastic polymer particles; and thereafter, the solidified particles are separated from the immiscible material, typically by dissolving the immiscible material in a suitable solvent.

Mode for Carrying Out the Invention

[0014] In this application: · Any description, even if related to a specific embodiment, is applicable to other embodiments of the present disclosure and can be exchanged with other embodiments. · When an element or component is said to be included in and / or selected from a list of enumerated elements or components, in the relevant embodiments explicitly contemplated herein, the element or component can be any one of the individual enumerated elements or components, or can also be selected from a group consisting of any two or more of the explicitly enumerated elements or components, and it should be understood that any element or component enumerated in the list of elements or components can be omitted from such a list. · Any enumeration in this specification of a numerical range by endpoints includes all numbers included within the enumerated range as well as the endpoints of the range and equivalents. · The terms "a", "an", or "the" mean "one or more" or "at least one" unless otherwise specified, and can be used interchangeably with each other. · The term "and / or" used in the form of "A and / or B" means only A, only B, or A and B together.

[0015] The first object of the present invention is an aggregate of particles composed of a thermoplastic composition containing at least one semi-aromatic polyamide, wherein the particles have a volume-based median particle size D(v,0.5) of 0.1 to 50.0 μm and the following relational expression (I):

Number

[0016] Thermoplastic composition The thermoplastic composition contains at least one semi-aromatic polyamide. The expression semi-aromatic polyamide refers to a polyamide containing repeating units derived from at least one aromatic monomer and repeating units derived from at least one aliphatic monomer. The aromatic monomer may be a diamine, a diacid, or an amino acid.

[0017] In one embodiment, the semi-aromatic polyamide may contain repeating units derived from an aromatic diamine.

[0018] The semi-aromatic polyamide may contain repeating units derived from an aromatic diamine in an amount of at least 50 mol%, typically at least 70 mol%, based on the total amount of diamine units in the polyamide.

[0019] Preferably, the semi-aromatic polyamide contains repeating units derived from an aromatic diamine having 6 to 18 carbon atoms.

[0020] Examples of suitable C6-C18 aromatic diamines include, but are not limited to, m-phenylenediamine (MPD), p-phenylenediamine (PPD), 3,4'-diaminodiphenyl ether (3,4'ODA), 4,4'-diaminodiphenyl ether (4,4'-ODA), p-xylylenediamine (PXD), and m-xylylenediamine (MXD).

[0021] Notable non-limiting examples of suitable polyamides containing aromatic diamines are, for example, polyamides containing repeating units of the formula MXDZ (wherein Z represents a unit derived from a linear or branched aliphatic or cycloaliphatic diacid having z carbon atoms, z is an integer of 6 or more, and MXD is m-xylylenediamine). Z is preferably selected from aliphatic diacids having 6 to 16 carbon atoms. Notable non-limiting examples are adipic acid, sebacic acid, or dodecanedioic acid. More preferably, Z is adipic acid.

[0022] In some embodiments, the semi-aromatic polyamide may further contain repeating units of the formula PXDZ (wherein PXD represents a unit derived from p-xylylenediamine and Z is as defined above).

[0023] In certain embodiments, the semi-aromatic polyamide is a polyamide of the formula A / MXDZ, wherein A is a repeating unit derived from at least one of an amino acid, i.e., a molecule containing a primary carboxylic acid and a primary amine, a lactam, or a unit having the formula (Ca diamine).(Cb diacid), "a" represents the number of carbon atoms of the diamine, "b" represents the number of carbon atoms of the diacid, and "a" and "b" are independently integers from 4 to 36, preferably from 6 to 18. The component (Ca diamine) is preferably selected from the group consisting of linear or branched aliphatic diamines, cycloaliphatic diamines, and alkyl aromatic diamines. Examples are, for example, hexamethylenediamine, decanediamine, dodecanediamine, and MXD.

[0024] The component (dicarboxylic acid) is preferably selected from the group consisting of linear or branched aliphatic dicarboxylic acids, cycloaliphatic dicarboxylic acids, and aromatic dicarboxylic acids. Examples are, for example, adipic acid, sebacic acid, dodecanedioic acid, or 3-(aminomethyl)benzoic acid (3-AMBa).

[0025] In an advantageous embodiment, unit A or Z can be derived from renewable materials. Non-limiting examples of this type of suitable polyamide are PA MXD6, PA MXD10.

[0026] In another embodiment, the semi-aromatic polyamide contains repeating units derived from aromatic dicarboxylic acids.

[0027] In a preferred embodiment, the semi-aromatic polyamide contains repeating units of formula XT, wherein X represents a unit derived from a linear or branched aliphatic or cycloaliphatic diamine having x carbon atoms, x is an integer of 6 or more, and T represents a unit derived from terephthalic acid.

[0028] The semi-aromatic polyamide contains at least 50 mol%, typically at least 70 mol%, and further at least 90 mol% of repeating units of formula XT.

[0029] The semi-aromatic polyamide may contain two or more repeating units of formula XT in which each unit X is derived from a different diamine. Alternatively, the semi-aromatic polyamide may contain, in addition to the repeating units of formula XT, repeating units of formula X’T, wherein X’ represents a unit derived from a linear or branched aliphatic or cycloaliphatic diamine having x’ carbon atoms, and x’ is an integer less than 6.

[0030] In some embodiments, the semi-aromatic polyamide may further contain repeating units of formula XI, wherein I represents a unit derived from isophthalic acid and X is as defined above.

[0031] The unit X in formula XT, or unit XI if present, is derived from a linear or branched aliphatic or cycloaliphatic diamine having x carbon atoms, where x is greater than 6 and up to 36, preferably from 8 to 18. Unit X is preferably derived from an aliphatic diamine selected from the group consisting of 1,8-octanediamine, 1,9-nonanediamine, 2-methyl-1,8-octanediamine (Me8), 1,10-decanediamine, 1,12-dodecanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 5-methyl-1,9-nonanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, isophoronediamine, and mixtures thereof. In a preferred embodiment of the present invention, unit X is derived from the group of aliphatic diamines consisting of 1,8-octanediamine, 1,9-nonanediamine, 2-methyl-1,8-octanediamine, 1,10-decanediamine, 1,12-dodecanediamine, and mixtures thereof. More preferably, unit X is derived from the group of aliphatic diamines consisting of 1,9-nonanediamine, 2-methyl-1,8-octanediamine, 1,10-decanediamine, 1,12-dodecanediamine, and mixtures thereof.

[0032] In certain embodiments, the aliphatic diamine can be derived from renewable materials. Notable non-limiting examples of such diamines are 1,10-decanediamine and 1,12-dodecanediamine, which can be derived from, for example, castor oil.

[0033] Notable non-limiting examples of suitable polyamides containing only the repeating units of formula XT or XT / X’T are PA 6T, PA 8T, PA Me8T, PA 9T, PA Me8T / 9T, PA 10T, PA 11T, PA 12T, PA 6T / 9T, PA 9T / 10T, PA 9T / 11T, PA 9T / 12T, PA 6T / 10T, PA 6T / 11T, PA 6T / 12T, PA 10T / 11T, PA 10T / 12T, PA 11T / 12T.

[0034] In certain embodiments, the semi-aromatic polyamide is a copolyamide of the formula Y / XT, where XT is as defined above and Y is an amino acid, i.e., a molecule containing a primary carboxylic acid and a primary amine, a lactam, or a repeating unit derived from at least one of the units having the formula (Cn diamine) . (Cm diacid), where "n" represents the number of carbon atoms of the diamine, "m" represents the number of carbon atoms of the diacid, and "m" and "n" are, independently of each other, integers from 4 to 36, preferably from 6 to 18. The component (Cn diamine) is preferably selected from the group consisting of linear or branched aliphatic diamines, cycloaliphatic diamines, and alkyl aromatic diamines. The component (Cm diacid) is preferably selected from the group consisting of linear or branched aliphatic diacids, cycloaliphatic diacids, and aromatic diacids.

[0035] In a preferred embodiment, the unit Y in the formula Y / XT can be derived from renewable materials. Notable non-limiting examples of diacids or amino acids derived from renewable raw materials are, for example, sebacic acid or 3-(aminomethyl)benzoic acid (3-AMBa) which can be derived from furfural.

[0036] Notable non-limiting examples of suitable copolyamides of the formula Y / XT are polyamides of the formula Y / 6T, Y / 9T, Y / 10T, or Y / 11T, where Y is as defined above. Suitable copolyamides are, in particular, PA 10 / 6T, 6 PA 10 / 9T, PA 10 / 10T, PA 10 / 11T, PA 10 / 12T, PA 11 / 6T, PA 11 / 9T, PA 11 / 10T, PA 11 / 11T, PA 11 / 12T, PA 12 / 6T, PA 12 / 9T, PA 12 / 10T, PA 12 / 11T, PA 12 / 12T, PA 610 / 6T, PA 612 / 6T, PA 910 / 6T, PA 912 / 6T, PA 1010 / 6T, PA 1012 / 6T, PA 610 / 9T, PA 612 / 9T, PA 910 / 9T, PA 912 / 9T, PA 1010 / 9T, PA 1012 / 9T, PA 610 / 10T, PA 612 / 10T, PA 910 / 10T, PA 912 / 10T, PA 1010 / 10T, PA 1012 / 10T, PA 610 / 12T, PA 612 / 12T, PA 910 / 12T, PA 912 / 12T, PA 1010 / 12T, PA 11 / 6T / 9T, PA 11 / 6T / 10T, PA 11 / 6T / 11T, PA 11 / 6T / 12T, PA 11 / 9T / 10T, PA 11 / 9T / 11T, PA 11 / 9T / 12T, PA 11 / 10T / 11T, PA 11 / 10T / 12T, PA 11 / 11T / 12T, PA 12 / 6T / 10T, PA 12 / 6T / 11T, PA 12 / 6T / 12T, 12 / 9.T / 10.T, PA 12 / 9T / 11T, PA 12 / 9T / 12T, PA 12 / 10T / 11T, PA 12 / 10T / 12T, PA 12 / 11T / 12T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T polyamides.

[0037] The thermoplastic composition may be composed of a semi-aromatic polyamide.

[0038] Alternatively, the thermoplastic composition may include one or more additives. Examples of suitable additives include, but are not limited to, fillers, reinforcing agents, pigments, pH adjusters, lubricants, heat stabilizers, light stabilizers, antioxidants, processing aids, and combinations thereof. Examples of fillers include, but are not limited to, glass fibers, glass particles, mineral fibers, carbon fibers, oxide particles (such as titanium dioxide, silica, zinc oxide, cerium oxide, and zirconium dioxide), metal particles (such as aluminum powder), talc, wollastonite, calcium carbonate, mica, and any combination thereof. Examples of pigments include, but are not limited to, organic pigments, inorganic pigments, carbon black, and any combination thereof.

[0039] The polymer composition may further include a flame retardant such as a halogenated flame retardant and a halogen-free flame retardant.

[0040] The additives can be present in the thermoplastic composition in an amount of 0.1 wt% to about 40.0 wt%, further 1.0 wt% to 35.0 wt%, or 5.0 wt% to 30.0 wt% based on the total weight of the thermoplastic composition.

[0041] In certain embodiments, the thermoplastic composition may include one or more thermoplastic polymers different from the semi-aromatic polyamide. Examples of suitable polymers include, but are not limited to, impact modifiers. The polymer backbone of the impact modifier may be selected from polyethylene and its copolymers, such as ethylene-butene; ethylene-octene; polypropylene and its copolymers; polybutene; polyisoprene; ethylene-propylene rubber (EPR); ethylene-propylene-diene monomer rubber (EPDM); ethylene-acrylate rubber; butadiene-acrylonitrile rubber, ethylene-acrylic acid (EAA), ethylene-vinyl acetate (EVA); acrylonitrile-butadiene-styrene rubber (ABS), block copolymer styrene ethylene butadiene styrene (SEBS); block copolymer styrene butadiene styrene (SBS); methacrylate-butadiene-styrene (MBS) type core-shell elastomer, or an elastomeric backbone containing one or more mixtures of the above.

[0042] When the impact modifier is functionalized, the functionalization of the backbone can occur by copolymerization of monomers containing the functionalization or by grafting of the polymer backbone with additional components. Specific examples of functionalized impact modifiers include, inter alia, terpolymers of ethylene and acrylic esters and glycidyl methacrylate, copolymers of ethylene and butyl acrylate; copolymers of ethylene and butyl acrylate and glycidyl methacrylate; ethylene-maleic anhydride copolymers; EPR grafted with maleic anhydride; styrene copolymers grafted with maleic anhydride; SEBS copolymers grafted with maleic anhydride; styrene-acrylonitrile copolymers grafted with maleic anhydride; ABS copolymers grafted with maleic anhydride.

[0043] Functionalized polyolefin impact modifiers are commercially available, including maleated polypropylene and ethylene-propylene copolymers available as Exxelor® PO, and maleic anhydride-functionalized ethylene-propylene copolymer rubbers containing about 0.6 weight percent pendant succinic anhydride groups, such as Exxelor® VA1801 from Exxon Mobil Chemical Company; acrylate-modified polyethylene available as Surlyn®, such as Surlyn® 9920 acrylic acid or methacrylic acid-modified polyethylene from Dow Inc.; maleic anhydride-modified SEBS block copolymers such as Kraton® FG1901X, a SEBS grafted with about 2 weight percent maleic anhydride available from Kraton Polymers; maleic anhydride-functionalized EPDM terpolymer rubbers such as Royaltuf® 498, a 1% maleic anhydride-functionalized EPDM available from SI Group.

[0044] Other desirable functionalized impact modifiers include, but are not limited to, ethylene - higher α-olefin polymers and ethylene - higher α-olefin - diene polymers grafted or copolymerized with reactive carboxylic acids or their derivatives, such as acrylic acid, methacrylic acid, maleic anhydride, or their esters. Suitable higher α-olefins include, but are not limited to, C3 - C8 α-olefins such as propylene, 1-butene, 1-hexene, and styrene. Alternatively, copolymers having structures containing such units can also be obtained by hydrogenation of suitable homopolymers and copolymers of polymerized 1-3 diene monomers. For example, polybutadienes having various levels of pendant vinyl units are readily available and can be hydrogenated to obtain ethylene-butene copolymer structures. Similarly, hydrogenation of polyisoprene can be used to provide equivalent ethylene-isobutylene copolymers.

[0045] Among the reactive impact modifiers, a random terpolymer of ethylene, an acrylate ester, and glycidyl methacrylate can be mentioned, which is commercially available from Arkema (Bristol, PA, USA) under the trade name Lotader® AX8900. Another example of the aforementioned reactive impact modifier is Paraloid EXL TM which is commercially available from Dow Inc. (Midland, MI, USA) under the name Paraloid EXL 2314. It is a core-shell type acrylate-based impact modifier mainly consisting of a core made of crosslinked poly(n-butyl acrylate) rubber and having a shell phase mainly consisting of a poly(methyl methacrylate)-poly(glycidyl methacrylate) copolymer.

[0046] The thermoplastic composition may contain at least one impact modifier in an amount of 0.5 wt% to 25.0 wt% based on the total weight of the composition. The impact modifier may be at least 1.0 wt%, at least 2.0 wt%, or at least 3.0 wt%, and further at least 5.0 wt% of the total weight of the composition. The impact modifier is typically 20.0 wt% or less, 15.0 wt% or less, 12.0 wt% or less, and further 10.0 wt% or less. Suitable ranges may be, for example, 0.5 to 15.0 wt%, further 0.5 to 12.0 wt%, and further 2.0 to 10.0 wt%.

[0047] Particle As used herein, the term "particle" refers to an individualized entity.

[0048] The particles have a volume-based median particle size D(v,0.5) of 0.1 to 50.0 μm and a particle size distribution that satisfies the following relational expression (I):

Equation

[0049] In relational expression (I), ·D(v,0.9) is the size of the particles smaller than which 90% of the sample is, ·D(v, 0.5) is the particle size at which 50% of the sample is smaller and 50% is larger, ·D(v, 0.1) is the particle size at which 10% of the sample is smaller.

[0050] In this specification, the particle size distribution refers to the volume distribution unless otherwise specified. The particle size distribution can be determined according to methods known in the art. In particular, the particle size and particle size distribution were determined by laser diffraction of an isopropanol suspension of the particle aggregates. The MicroTrac S3500 laser diffraction apparatus can be used according to the manufacturer's instructions or known methods. The detailed method is disclosed in the experimental section.

[0051] The particles in the aggregates of the present invention have a median particle size D(v, 0.5) of 0.1 to 50.0 μm, typically 1.0 to 50.0 μm. The median particle size D(v, 0.5) may advantageously be at least 1.5 μm, further at least 2.5 μm, and further at least 5.0 μm. The average particle size D(v, 0.5) may advantageously be less than 50.0 μm, further less than 45.0 μm. In some embodiments, the average particle size D(v, 0.5) is 2.5 μm to 40.0 μm, preferably 5.0 μm to 30.0 μm, or 7.5 μm to 25.0 μm.

[0052] The particles may further have a particle size distribution such that D(v, 0.9) is 100.0 μm or less, typically 65.0 μm or less, and further 50.0 μm or less.

[0053] In addition, the particles may further have a particle size distribution such that D(v, 0.1) is at least 1.0 μm, typically at least 2.5 μm, and more typically at least 5.0 μm.

[0054] Any combination of the ranges of D(v, 0.1), D(v, 0.5), and D(v, 0.9) is contemplated in this disclosure.

[0055] The particles of the present invention have the relational expression (I):

Number

[0056] In certain embodiments, the particle size distribution is given by the relational expression (Ia):

Number

Number

[0057] The particle size distribution may be such that it also satisfies the following relational expression (II):

Number

[0058] Advantageously, the particles are characterized by a combination of the following properties:

[0059] · D(v, 0.5) of 0.1 to 50.0 μm, typically 1.0 to 50.0 μm, 2.5 μm to 40.0 μm, preferably 5.0 μm to 30.0 μm, and more preferably 7.5 μm to 25.0 μm; and · D(v, 0.9) of 100.0 μm or less, typically 65.0 μm or less, and more typically 50.0 μm or less; and / or

Number

[0060] The particles preferably have a regular shape, i.e., generally a rounded shape.

[0061] In one aspect of the present invention, the particles are characterized by an aspect ratio of 0.8 to 1.3. The aspect ratio is defined as the ratio of the longest dimension to the shortest dimension of the particles determined by image analysis of a photograph of an aggregate of particles taken with a scanning electron microscope, as detailed in the experimental section.

[0062] Method for producing particles An aggregate of particles composed of the thermoplastic composition detailed above is prepared according to a melt extrusion process in which the thermoplastic composition and a soluble material immiscible with the thermoplastic composition are typically mixed in an extruder at a temperature higher than the melting point or softening temperature of the thermoplastic composition and at a shear rate high enough to disperse the thermoplastic composition in the soluble material; then, the molten mixture is cooled to below the melting point or softening temperature of the thermoplastic composition to form a solidified matrix containing thermoplastic composition particles; and this is then separated from the soluble material.

[0063] The term "immiscible" is used to refer to a mixture of components that form two or more separate phases when combined.

[0064] The term "soluble" is used in its conventional meaning to refer to a substance that can be dissolved.

[0065] In a preferred embodiment, the method comprises · mixing a mixture comprising a thermoplastic composition containing at least one semi-aromatic polyamide as defined above and a soluble material immiscible with the thermoplastic composition at a temperature higher than the melting point or glass transition temperature of the thermoplastic composition and at a shear rate high enough to disperse the thermoplastic composition in the soluble material immiscible with the thermoplastic composition; ·Cooling the mixture to a temperature below the melting point or glass transition temperature of the thermoplastic composition to form solidified pellets, strands, or pastes containing the thermoplastic composition dispersed in the soluble material; ·Contacting the solidified pellets, strands, or pastes with a solvent capable of selectively dissolving the soluble material to obtain an aggregate of particles composed of the thermoplastic composition; and ·Optionally drying the aggregate of particles; including.

[0066] The particles have a median particle size D(v,0.5) of 0.1 to 50.0 μm and a particle size distribution defined by relational expression (I).

[0067] To avoid misunderstanding, it is explicitly stated that the expression "soluble material" will be used hereinafter to refer to a soluble material that is immiscible with the thermoplastic composition.

[0068] The soluble material is not particularly limited as long as it can be processed at a temperature higher than the melting point or glass transition temperature of the thermoplastic composition and can be dissolved by a solvent that cannot dissolve the thermoplastic composition. The soluble material is preferably a material that can be melted or softened at a temperature at which the thermoplastic composition melts or softens, for example, 100°C to 300°C. In addition, the soluble material can be kneaded with the thermoplastic composition and can form a separate phase in the molten state or solidified state.

[0069] In a preferred embodiment, the soluble material is a water-soluble material. Examples of such water-soluble materials include, but are not limited to, sugars such as monosaccharides, oligosaccharides, polysaccharides, sugar alcohols, polydextrose, maltodextrin, and inulin; and water-soluble resins. Among water-soluble polymers, linear polymers having hydrophilic groups such as -O-, -CONH-, -COOH, or -OH can be mentioned. Examples include polyacrylamide, poly(acrylic acid), poly(methacrylic acid), poly(itaconic acid), poly(vinyl alcohol), poly(ethylene oxide) and its copolymers, poly(propylene oxide) and its copolymers, and polyesters containing repeating units derived from alkylene oxides. These water-soluble materials can be used alone or in combination, respectively.

[0070] In a preferred embodiment, the soluble material is selected from the group consisting of water-soluble polymers. More preferably, the water-soluble material is selected from the group consisting of poly(ethylene oxide), its copolymers, and polyesters containing repeating units derived from alkylene oxides.

[0071] The poly(ethylene oxide) suitable for the method of the present invention typically has a number average molecular weight Mn in the range of 2,000 to 200,000 g / mol, preferably 15,000 to 150,000 g / mol. Advantageous results were obtained with poly(ethylene oxide) having a molecular weight Mn in the range of 15,000 to 45,000 g / mol.

[0072] Examples of water-soluble polyester polymers containing repeating units derived from ethylene oxide include · at least one dicarboxylic acid component, and · at least one diol component, wherein at least 2 mol% of the diol component is a poly(alkylene oxide) of the formula: H(O-C p H 2p ) q -OH (wherein p is an integer from 2 to 4, preferably p is 2, and q varies from 2 to 10), and Examples include polyesters containing repeating units derived from

[0073] Suitable polyesters can further include repeating units derived from a difunctional monomer containing at least one SO3M group bonded to an aromatic moiety, where M is H or a metal ion selected from the group consisting of sodium, potassium, calcium, lithium, magnesium, silver, aluminum, zinc, nickel, copper, palladium, iron, and cesium, preferably a metal ion selected from the group consisting of sodium, lithium, and potassium. The functional group is carboxy. Specific examples of such polyesters include those commercially available under the trademark AQ Polymers from Eastman, particularly those having a glass transition temperature in the range of about 25°C to about 50°C. The most preferred is Eastman AQ38S, a polyester identified as diethylene glycol / cyclohexanedimethanol / isophthalate / sulfoisophthalate polyester, or Eastman AQ48, a sulfopolyester.

[0074] The amount of soluble material in the mixture with the thermoplastic composition may be 30 wt% to 95 wt%, 35 wt% to 85 wt%, or even 40 wt% to 80 wt% based on the total weight of the mixture.

[0075] When a polyamide containing the repeating unit of Formula 9T is processed with poly(ethylene glycol) having a molecular weight of 30,000 to 45,000 g / mol at a weight ratio of 50:50, good results were obtained with respect to particle size and particle size distribution.

[0076] When the thermoplastic composition contains additives or additional thermoplastic polymers in addition to the semi-aromatic polyamide, these can be added to the mixture before melt mixing with the immiscible material. The additional components can be physically or melt blended with the semi-aromatic polyamide in a melt blending apparatus. The additional components can be blended with the thermoplastic polymer immediately before or considerably before the production of the mixture.

[0077] More generally, the step of mixing the mixture of the thermoplastic composition and the soluble material can be carried out using any suitable apparatus. An endless screw mixer, a stirrer mixer, or a twin-screw extruder suitable for the temperature required to melt the mixture can be used. The amount of energy added to this step can be adjusted to control the size of the particles obtained therefrom. Those skilled in the art can adjust the apparatus (e.g., screw shape) and the parameters of the apparatus (e.g., rotational speed) to obtain particles of the desired size.

[0078] The expression "mixing the mixture" in the case of a thermoplastic composition and a soluble material encompasses both the case where the mixture is prepared in an apparatus different from the apparatus for performing the mixing step and the case where the apparatuses are the same.

[0079] According to one embodiment, · When a semi-crystalline semi-aromatic polyamide is used, the mixing step is carried out at a temperature selected to be at least 10 °C higher, for example at least 15 °C or 20 °C higher, than the melting point (Tm) of the polymer or the thermoplastic composition containing the semi-crystalline semi-aromatic polyamide. · When an amorphous semi-aromatic polyamide is used, the mixing step is carried out at a temperature selected to be at least 50 °C higher than the glass transition temperature (Tg) of the amorphous polymer or the thermoplastic composition containing the amorphous semi-aromatic polyamide.

[0080] According to a preferred embodiment, the mixing step is carried out at a temperature above 250 °C, for example above 260 °C, above 270 °C, or above 280 °C.

[0081] The mixing step is typically carried out at a temperature lower than the temperature at which the thermoplastic composition begins to decompose.

[0082] The step of processing the mixture into pellets, strands, or paste can be carried out by an extrusion process through a die.

[0083] The step of mixing the composition and processing it into pellets, strands, or a paste is preferably carried out in an extruder equipped with an extrusion die.

[0084] The cooling step is carried out at a temperature below 80 °C, for example below 50 °C, by any suitable means. In particular, air cooling or quenching in a liquid such as water can be mentioned.

[0085] The step of contacting the pellets, strands, or paste with a solvent capable of selectively dissolving the soluble material may be a step of immersing the pellets, strands, or paste in one or more baths containing the selected solvent. The solvent, preferably water, is optionally heated to a temperature of up to 95 °C, for example about 40 °C, about 60 °C, or about 80 °C. In the case of the solvent, especially water, an acid or base selected from the group consisting of potassium hydroxide, sodium hydroxide, lithium hydroxide, potassium carbonate, sodium carbonate, lithium carbonate, organic amines, hydrochloric acid, and sulfuric acid may be added. By this step, the dissolution or dispersion of the soluble material is promoted, and as a result, the particles of the thermoplastic composition can be recovered.

[0086] The steps of the method of the present invention may be carried out batchwise or continuously.

[0087] According to one embodiment, the step of cooling the pellets, paste, or strands at a temperature below 80 °C, for example below 50 °C, and the step of contacting the pellets, paste, or strands with a solvent, especially water, may be carried out simultaneously in the same apparatus, for example by immersing the pellets or strands in the solvent.

[0088] The method of the present invention may also include an additional step of drying the particles and / or an additional step of sieving the particles. The drying step can be carried out, for example, in a fluidized bed.

[0089] Use of the particles for producing a composite material The aggregate of particles of the present invention is particularly suitable for use in the production of composite materials comprising continuous fibers and a matrix of a thermoplastic composition.

[0090] As used herein, the term "fiber" has its ordinary meaning known to those skilled in the art and can include one or more fiber materials suitable for reinforcing composite materials that can take any form of particles, flakes, whiskers, short fibers, continuous fibers, sheets, yarns, and combinations thereof.

[0091] Accordingly, a further object of the present invention is a method for producing a composite material comprising a fibrous material of continuous fibers and a matrix comprising the thermoplastic composition detailed above, i) immersing the fibrous material in a bath containing an aqueous dispersion containing an aggregate of particles consisting of the thermoplastic composition which is the first object of the present invention, and ii) drying the fibrous material, which comprises a method.

[0092] The impregnation step of the fibrous material is carried out by passing the material through a continuous impregnation apparatus equipped with an immersion tank containing an aqueous dispersion containing the aggregate of particles detailed above.

[0093] The aggregate of particles consisting of the thermoplastic composition is mixed with water to form this dispersion. The concentration of particles in the dispersion can be varied and can be adjusted by those skilled in the art based on the content of the thermoplastic composition required in the final composite material.

[0094] The fibrous material is circulated in a bath formed by the aqueous dispersion. The median diameter D(v,0.5) of the particles in the aqueous dispersion is 0.1 to 50.0 μm so as to penetrate into the fibers. Preferably, the median diameter D(v,0.5) of the particles is 2.5 μm to 40.0 μm, preferably 5.0 μm to 30.0 μm, or 7.5 μm to 25.0 μm.

[0095] The median diameter D(v, 0.5) of the particles can be conveniently selected according to the diameter of the fibrous material to be impregnated. In some advantageous cases, the median diameter D(v, 0.5) of the particles is 1.0 to 4.0 times, and further preferably 1.0 to 3.5 times, the average diameter of the fibrous material to be impregnated.

[0096] The particle size distribution is a distribution that satisfies the relational expression (I), and further preferably (Ia) or (Ib). Although not bound by theory, a particle size distribution biased towards larger particle sizes, as represented by the relational expression (I) among the values of D(v, 0.1), D(v, 0.5), and D(v, 0.9) of the particle size distribution, is considered advantageous for the operation of the slurry impregnation process in order to reduce the risk of foaming caused by small-diameter particles when forming a slurry.

[0097] The aqueous dispersion (or slurry) containing the particle aggregates may contain additional components. These may be, for example, emulsifiers or dispersants for improving the stability of the slurry during the impregnation process.

[0098] The aqueous dispersion may also contain additives that need to remain in the final composite material. Non-limiting examples are, for example, inorganic additives.

[0099] The pre-impregnated fibrous material exits the tank and is directed towards a drying device for evaporating moisture. Any drying device can be used to evaporate water in this step.

[0100] The constituent fibers of the fibrous material can be conveniently selected from the group consisting of carbon fibers, glass fibers, basalt fibers, silica fibers, silicon carbide fibers, and aramid fibers. Fibers derived from plants can also be used. Examples include natural linen, hemp, silk, especially spider silk, sisal fibers, and other cellulose fibers.

[0101] These constituent fibers may be used alone or as a mixture.

[0102] The fibers selected may be single strands, multi-strands, or a mixture of both. Additionally, they may have multiple shapes. Thus, they may be in the form of short fibers that will later produce felt or non-woven fabric in the form of strips, sheets, strings, rovings, or pieces. Alternatively, they may be in the form of continuous fibers that produce 2D fabrics, fibers, or unidirectional (UD) rovings, or non-woven fabrics. The constituent fibers of the fibrous material may be in the form of a mixture of these reinforcing fibers having different geometric shapes. Preferably, the fibers are continuous.

[0103] Preferably, the fibrous material is composed of continuous fibers of carbon, glass, or silicon carbide, or a mixture thereof, particularly carbon fibers.

[0104] Due to the particle size of the thermoplastic composition of the present invention, the thermoplastic composition is uniformly and homogeneously distributed around the fibers. In this type of material, in order to minimize the voids between the fibers, i.e., the gaps, the impregnating thermoplastic polymer must be distributed as uniformly as possible within the fibers. The presence of voids in this type of material acts as a point where stress concentrates, for example when subjected to mechanical tensile stress, and at that time, a starting point of fracture may be formed in the composite material, making it mechanically weak. Therefore, the uniform distribution of the polymer matrix improves the mechanical strength and homogeneity of the composite material.

[0105] Typically, the volume percentage ratio of the thermoplastic composition to the fibrous material varies from 40% to 25%, preferably from 45% to 125%, more preferably from 45% to 80%.

[0106] The resulting composite material is a semi-finished product in the form of a tape or sheet having an adjusted thickness and width for use in the manufacture of three-dimensional structural components. These can be used in the transportation fields such as automobiles, aviation, ships, or railways; renewable energy, especially wind energy and hydropower energy; energy storage devices, solar panels; thermal protection panels; sports and leisure equipment, health and medical equipment, smart devices; articles in gas storage or transportation devices. The composite material obtained from the method of the present invention can be advantageously used in the manufacture of hydrogen gas storage tanks or transportation tanks.

[0107] The above embodiments are intended to be illustrative and not limiting. Additional embodiments are within the concept of the present invention. In addition, although the present invention is described in relation to specific embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the present invention.

Examples

[0108] Raw materials PA9T: A semi-aromatic polyamide commercially available from Kuraray as GENESTAR GC98018. This is a 50:50 copolymer of 1,9-nonanediamine and terephthalic acid, and 2-methyl-1,8-octanediamine and terephthalic acid.

[0109] PEG-1: Poly(ethylene oxide), Mn about 35000 g / mol (PolyglyKol35000S, available from Clariant) was used as the soluble material.

[0110] Example 1 - Preparation of Particles Using the Melt Emulsification Process A Leistritz co-rotating twin-screw extruder (D = 18 mm, L / D = 60) was used. Pellets of PA9T and PEG-1 (weight ratio 50:50) were both put into the first zone of the extruder. An open barrel was used for degassing in the ninth zone, and ten heating zones were used. The first zone was heated to 20 °C, the second zone to 270 °C, and the third zone to 290 °C. A temperature of 290 °C was applied up to the last zone. The applied screw speed was approximately 200 rpm. The throughput was 8 kg / hr, 4 kg / hr per feeder. The obtained molten particles surrounded by molten PEG-1 were collected into a flask filled with cold water to obtain a slurry containing PA9T particles. The particles were collected by centrifugation. Washing and centrifugation processes (1 - 5 times) were applied to remove PEG-1. Then, the particles were dried at 90 °C.

[0111] The characteristics of the particles are summarized in Table 1 below.

[0112] Comparative Example 1 The reactor flakes of PA9T were pulverized using a Fluid Energy Model4 micro jet mill equipped with a material inlet cooled by liquid nitrogen. The pulverizer was operated using an inlet pressure P1 of 621 kPa, a pulverizer pressure P2 of 414 kPa, and a feed rate of 0.5 kg / hr. The obtained powder was collected and analyzed, and the particle characteristics were summarized in Table 1 below.

[0113] Determination of particle size The particle size distribution of the polymer powder was determined by the wet method using a MicroTrac S3500 laser diffraction apparatus. The S3500 measures particle sizes in the range of 0.02 to 2,800 μm. The powders of Example 1 and Comparative Example 1 were dispersed in isopropanol. A laser beam was irradiated onto a sample cell containing a flowing stream of particles suspended in isopropanol. The light hitting the particles was scattered, and the scattered light was measured by a photodiode array. The photodetector array measures the amount of light (light beam) at specific angles. Subsequently, an electrical signal proportional to the measured light beam value is processed by a computer / software, and a multi-channel histogram of the particle size distribution is formed. The particle size distribution is reported by volume in Table 1.

[0114]

Table 1

[0115] Particle aspect ratio The powder samples of Example 1 and Comparative Example 1 were dispersed on carbon tape using an applicator stick and then imaged by a variable pressure scanning electron microscope (SEM). The obtained image files were analyzed with ImageJ to measure the length and width of the particles. The length was measured along the longest dimension of the particle, and the width was measured along the shortest dimension of the particle.

[0116] The aspect ratio of the particles was calculated as length / width. For each set of powder samples, a series of 10 particles were randomly selected from one image, and the length and width of each of these individual particles were measured. Finally, the mean and standard deviation of the aspect ratio parameter were calculated.

[0117] The particles of Example 1 have an aspect ratio of 1.1 ± 0.1. This is an indicator of particles having a shape close to a rounded sphere.

[0118] The particles of Comparative Example 1 have an aspect ratio of 1.7 ± 0.5.

[0119] Basic procedures for composite material manufacturing Using a slurry-based impregnation process, unidirectional carbon fiber tapes impregnated with the polymer particles of Example 1 and Comparative Example 1 were formed.

[0120] Unsized carbon fibers commercially available from Hyosung under the trade name TANSOME H2550 12K were used. These were supplied in the form of tows containing 12,000 individual fibers. The thickness of the individual fibers was approximately 7 μm. A sufficient number of fibers were used to produce a unidirectional tape 76 mm wide. A dry web of continuously aligned parallel fibers was passed through an aqueous bath containing water, the polymer particles of Example 1 or Comparative Example 1, and a surfactant (Igepal CA-630, supplied by Sigma Aldrich).

[0121] At the start of the run, initially 297 g of polymer and 29.5 kg of water were contained in the aqueous bath. A separate second tank was formed to hold 882.5 g of polymer, 4.4 g of surfactant, and 5.0 kg of water. This tank was made to function as a high-concentration refill tank to the first tank because the loss rate of the polymer in the main aqueous bath did not match the loss rate of water during a typical slurry impregnation process. The flow of the refill liquid from the refill tank was pumped into the main slurry bath at a rate sufficient to maintain a target fiber volume fraction (Vf) of 0.60, which was determined by on-the-fly weight checks.

[0122] The line was equilibrated for 1.5 hours before the prepreg tape was recovered. After passing through the water bath, the web of aligned parallel fibers was passed under a series of infrared lamps to promote water evaporation and polymer consolidation. The tape was then passed through a die heated to 340 °C, then through a heated calendar maintained at 120 °C, then through a series of cooling rolls, and then wound onto a cardboard core. The line speed was set at 1.0 m / second. The nominal fiber volume fraction of the prepreg tape was 0.60, resulting in a final polymer content of 32 wt% and a fiber areal weight of 124 g / m 2 resulting in.

[0123] Two tapes manufactured from the particles of Example 1 and Comparative Example 1 were cut, attached to epoxy, and polished so that the cross-section of the tape was visible. Thereafter, the polished tape pack was imaged using an optical microscope. The detailed sample preparation and imaging procedures are described in detail below.

[0124] Sample preparation: Samples of unidirectional tape were cut perpendicular to the fiber direction and then stabilized and cured with a two-component epoxy resin (such as Buehler's Epoxicure2 (trademark)). After curing, the pack was rough polished and finish polished step by step, first using sandpaper and then using diamond slurry on a felt pad. Sandpaper grits from 280 / P320 to 1200 / P4000 are suitable for the first polishing, and thereafter, diamond slurries with particle sizes of 3.0 μm, then 1.0 μm, and finally 0.1 μm are useful for the finish polishing. Suitable slurries are obtained from Electron Microscopy Sciences' Glennel (registered trademark) Diamond Suspension series.

[0125] Imaging: The finish polished samples were imaged at various magnifications (100 - 300 times) using an optical microscope.

[0126] The volume fractions of fibers, matrix, and porosity were extrapolated by image analysis using ImageJ software. The color threshold was adjusted step by step to create an image of only black and white pixels, keeping the voids or gaps black and showing both the fibers and the matrix in white. This was then repeated to generate an image where both the voids and the matrix were black and only the fibers were white. The pixels were counted in each resulting image to enable easy calculation of the proportion of each component.

[0127] The tape manufactured from Comparative Example 1 had a relatively large amount of voids, resin-rich regions, cracks / gaps within the tape width, and a very non-uniform tape thickness across the tape width. The porosity was calculated to be about 10%.

[0128] In contrast, the tape produced from Example 1 had a uniform tape thickness across the entire tape width, had only minor cracks / gaps, and had a very uniform fiber distribution with minimal voids or resin-rich regions. The porosity was calculated to be about 1%.

[0129] Fabrication and Property Evaluation of Laminates The composite material laminates were fabricated using a Rucks KV275.11 Upstroke Press with a size of 600 mm × 600 mm, a maximum platen temperature of 450 °C, and a maximum pressing force of 1000 kN. The tape was dried overnight at 120 °C for 18 hours and then annealed at 150 °C for 10 minutes. The ply stack was wrapped with Kapton(R) tape, sandwiched between aluminum sheets, and Zyvax Composite Shield Release was applied. The prepared ply stack was loaded onto a tool of 18 cm × 28 cm and placed into the press. Then, the prepared mold was heated according to the procedure shown in Table 2.

[0130] [Table 2]

[0131] Samples were cut from the obtained laminates and tested according to the ASTM standards shown in Table 3.

[0132] [Table 3]

[0133] The composite material laminates obtained from the polymer particles of Example 1 showed significantly higher flexural modulus, maximum flexural stress, and short beam shear strength compared to the laminates fabricated from the particles of Comparative Example 1.

Claims

1. An aggregate of particles comprising a thermoplastic composition containing at least one semi-aromatic polyamide, wherein the particle size is 0.1 to 50.0 μm, and the following relationship is given by (I): [Math 1] (In the formula, D(v, 0.9) represents the size of particles smaller than 90% of the sample, D(v, 0.5) represents the size of particles smaller than 50% of the sample and larger than 50%, and D(v, 0.1) represents the size of particles smaller than 10% of the sample.) An aggregate having a particle size distribution that satisfies the following conditions.

2. The particle size distribution is given by the following relationship (II) [Math 2] An aggregate of particles according to claim 1, satisfying the condition.

3. The aggregate of particles according to claim 1, wherein D(v, 0.9) is 100.0 μm or less, 65.0 μm or less, and 50.0 μm or less, and / or D(v, 0.1) is at least 1.0 μm, at least 2.5 μm, and at least 5.0 μm.

4. The aggregate of particles according to claim 1, wherein D(v, 0.5) is 1.0 to 50.0 μm, 2.5 μm to 40.0 μm, preferably 5.0 μm to 30.0 μm, and more preferably 7.5 μm to 25.0 μm.

5. The following relationship [Math 3] The aggregate of particles according to claim 1, characterized by a particle size distribution that satisfies the following conditions.

6. The aggregate of particles according to claim 1, wherein the semi-aromatic polyamide contains repeating units of formula XT (wherein X represents a unit derived from an aliphatic diamine having 8 to 36 carbon atoms, preferably 8 to 14 carbon atoms) or repeating units of formula MXDZ (wherein Z represents a unit derived from a linear or branched aliphatic or alicyclic diacid having z carbon atoms, z is an integer of 6 or more, preferably 6 to 36, and MXD is m-xylylenediamine).

7. The semi-aromatic polyamide is selected from the group consisting of PA 6T, PA 8T, PA Me8T, PA 9T, PA Me8T / 9T, PA 10T, PA 11T, PA 12T, PA 6T / 9T, PA 9T / 10T, PA 9T / 11T, PA 9T / 12T, PA 6T / 10T, PA 6T / 11T, PA 6T / 12T, PA 10T / 11T, PA 10T / 12T, PA 11T / 12T, PA 10 / 6T, 6 PA 10 / 9T, PA 10 / 10T, PA 10 / 11T, PA 10 / 12T, PA 11 / 6T, PA 11 / 9T, PA 11 / 10T, PA 11 / 11T, PA 11 / 12T, PA 12 / 6T, PA 12 / 9T, PA 12 / 10T, PA 12 / 11T, PA 12 / 12T, PA 610 / 6T, PA 612 / 6T, PA 910 / 6T, PA 912 / 6T, PA 1010 / 6T, PA 1012 / 6T, PA 610 / 9T, PA 612 / 9T, PA 910 / 9T, PA 912 / 9T, PA 1010 / 9T, PA 1012 / 9T, PA 610 / 10T, PA 612 / 10T, PA 910 / 10T, PA 912 / 10T, PA 1010 / 10T, PA 1012 / 10T, PA 610 / 12T, PA 612 / 12T, PA 910 / 12T, PA 912 / 12T, PA 1010 / 12T, PA 11 / 6T / 9T, PA 11 / 6T / 10T, PA 11 / 6T / 11T, PA 11 / 6T / 12T, PA 11 / 9T / 10T, PA 11 / 9T / 11T, PA 11 / 9T / 12T, PA 11 / 10T / 11T, PA 11 / 10T / 12T, PA 11 / 11T / 12T, PA 12 / 6T / 10T, PA 12 / 6T / 11T, PA 12 / 6T / 12T, 12 / 9.T / 10.T, PA 12 / 9T / 11T, PA 12 / 9T / 12T, PA 12 / 10T / 11T, PA 12 / 10T / 12T, PA 12 / 11T / 12T, PA MXD T / 10T, PA MPMD T / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA MXD6, PA MXD10; the aggregate of particles according to claim 1.

8. The aggregate of particles according to claim 1, wherein the thermoplastic composition contains at least one semi-aromatic polyamide and 0.1 to 40.0% by weight of at least one additional component selected from the group consisting of plasticizers, fillers, and impact modifiers.

9. A method for producing an aggregate of particles according to claim 1, - A step of mixing a thermoplastic composition containing at least one semi-aromatic polyamide and a soluble material that is miscible with the thermoplastic composition at a temperature higher than the melting point or glass transition temperature of the thermoplastic composition, and at a shear rate high enough to disperse the thermoplastic composition in the soluble material; - A step of cooling the mixture to below the melting point or glass transition temperature of the thermoplastic composition to form solidified pellets, strands, or pastes containing the thermoplastic composition dispersed in the soluble material; - A step of contacting solidified pellets, strands, or paste with a solvent capable of selectively dissolving soluble materials to obtain an aggregate of particles made of a thermoplastic composition; and - A process of selectively drying aggregates of particles; A method that includes this.

10. The method according to claim 9, wherein the soluble material is a water-soluble material, preferably selected from the group consisting of monosaccharides, oligosaccharides, polysaccharides, sugar alcohols, polydextrose, maltodextrin, and sugars including inulin, polyacrylamide, poly(acrylic acid), poly(methacrylic acid), poly(itaconic acid), poly(vinyl alcohol), poly(ethylene oxide) and its copolymers, poly(propylene oxide) and its copolymers, and polyesters containing repeating units derived from alkylene oxide.

11. The method according to claim 9, wherein the amount of soluble material in the mixture with the thermoplastic composition is 30% to 95% by weight, 35% to 85% by weight, and moreover, 40% to 80% by weight, based on the total weight of the mixture.

12. A liquid composition comprising the aggregate of particles described in claim 1 and water.

13. A method for producing a composite material comprising a fibrous material of continuous fibers and a matrix containing a thermoplastic composition, i) Immersing the fibrous material in a bath containing an aqueous dispersion containing the aggregate of particles described in claim 1, and ii) Drying the fibrous material, A method that includes this.

14. The method according to claim 13, wherein the continuous fiber is selected from carbon fiber; glass; silicon carbide; basalt; silica; natural fibers, particularly flax or hemp, lignin, bamboo, sisal, silk, or cellulose fibers, particularly viscose.

15. The method according to claim 13, further comprising the step of preparing an aggregate of particles according to the method of claim 9.

Images