Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/28—Formation of filaments, threads, or the like while mixing different spinning solutions or melts during the spinning operation; Spinnerette packs therefor
  • D01D5/30—Conjugate filaments; Spinnerette packs therefor
  • D01D5/34—Core-skin structure; Spinnerette packs therefor
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
  • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/09—Addition of substances to the spinning solution or to the melt for making electroconductive or anti-static filaments
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
  • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
  • D01F8/06—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyolefin as constituent
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2916—Rod, strand, filament or fiber including boron or compound thereof [not as steel]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2918—Rod, strand, filament or fiber including free carbon or carbide or therewith [not as steel]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2929—Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/30—Woven fabric [i.e., woven strand or strip material]
  • Y10T442/3146—Strand material is composed of two or more polymeric materials in physically distinct relationship [e.g., sheath-core, side-by-side, islands-in-sea, fibrils-in-matrix, etc.] or composed of physical blend of chemically different polymeric materials or a physical blend of a polymeric material and a filler material
  • Y10T442/3154—Sheath-core multicomponent strand material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
  • Y10T442/637—Including strand or fiber material which is a monofilament composed of two or more polymeric materials in physically distinct relationship [e.g., sheath-core, side-by-side, islands-in-sea, fibrils-in-matrix, etc.] or composed of physical blend of chemically different polymeric materials or a physical blend of a polymeric material and a filler material
  • Y10T442/641—Sheath-core multicomponent strand or fiber material

Definitions

• the present invention relates to a multilayer conductive fiber of core-shell structure, the core of which contains nanotubes, especially carbon nanotubes. It also relates to a process for manufacturing this fiber by coextrusion, as well as its uses. Finally, it relates to a composite material comprising such multilayer composite fibers bonded together by weaving or using a polymeric matrix.
• Carbon nanotubes are known and possess particular crystalline structures, tubular, hollow and closed, composed of atoms arranged regularly in pentagons, hexagons and / or heptagons, obtained from carbon.
• CNTs generally consist of one or more graphite sheets wound coaxially.
• SWNTs single wall nanotubes
• Multi Wall Nanotubes or MWNTs Multi Wall Nanotubes
• CNTs are commercially available or can be prepared by known methods. There are several methods for synthesizing CNTs, including electrical discharge, laser ablation and CVD (Chemical Vapor
• This process consists precisely in injecting a relatively high temperature carbon source onto a a catalyst which may itself consist of a metal such as iron, cobalt, nickel or molybdenum, supported on an inorganic solid such as alumina, silica or magnesia.
• Carbon sources may include methane, ethane, ethylene, acetylene, ethanol, methanol or even a mixture of carbon monoxide and hydrogen (HIPCO process).
• CNTs have many powerful properties, namely electrical, thermal, chemical and mechanical. Among their applications are, in particular, composite materials intended in particular for the automotive, nautical and aeronautical industries, electromechanical actuators, cables, resistant wires, chemical detectors, energy storage and conversion, electron emission displays, electronic components, and functional textiles. In the automotive, aeronautical and electronic fields, conductive loads such as NTCs allow the heat and electrical dissipation of heat and electricity accumulated during friction.
• the CNTs are in the form of a disorganized powder, consisting of entangled filaments, which makes them difficult to implement.
• the CNTs to be present in large quantities and oriented in a preferred direction.
• One of the solutions to overcome this problem is to develop composite fibers.
• the nanotubes may be incorporated in a matrix such as an organic polymer.
• this technique requires a high purity of the CNTs and an elimination of aggregates that these, because of their entangled structure, naturally tend to form. These aggregates are indeed detrimental to the spinning process and frequently lead to breakage of the composite fibers obtained.
• the conductivity of the composite fibers obtained according to the aforementioned technique is not always satisfactory. Indeed, the electrical properties of CNTs are all the better that they are dispersed homogeneously and randomly, while the spinning processes lead instead to a significant orientation of the CNTs.
• Still another route for making CNT composite fibers has been to coagulate a dispersion of CNTs in a polymer flow such as polyvinyl alcohol (FR 2 805 179).
• This coagulation method however does not achieve the high spinning speeds conventionally used today. It is indeed difficult to stabilize the co-flow of the dispersion of CNT and the coagulant solution, due to the change from a laminar regime to a turbulent regime at high speed, and also the fragility, in a viscous medium, of newly coagulated fibers.
• multilayer fibers of core-shell structure whose core contains a dispersion of CNTs.
• These fibers are in particular manufactured by co- extrusion of two polymer matrices based on thermoplastic polymer, one of which contains the CNTs.
• conductive fibers having a core-shell structure possibly obtained by coextrusion, comprising carbon nanotubes have been described.
• these fibers comprise a primary component forming the core and a secondary component forming the bark. Only the secondary component contains CNTs.
• the conductive fibers consist of a core containing a first dispersion of CNT and a bark containing a second dispersion of CNTs.
• the conductive material such as CNTs or carbon black is present only in the bark of the conductive fiber.
• the present invention thus relates to a multilayer conductive fiber, comprising:
• a core consisting of a first polymeric matrix containing at least one thermoplastic polymer and a dispersion of nanotubes of at least one chemical chemical element chosen from the elements of columns IHa, IVa and Va of the periodic table, said nanotubes being capable of providing thermal and / or electrical conduction, - a bark consisting of a second polymeric matrix containing at least one thermoplastic polymer other than polyvinyl alcohol and not containing a dispersion of nanotubes of at least one selected chemical chemical element among the elements of columns IHa, IVa and Va of the periodic table.
• the expression "included (e) between” must be interpreted as including the boundaries cited.
• the term "fiber” means a filament whose diameter is between 100 nm and 10 mm, advantageously between 100 nm and 3 mm, preferably between 1 ⁇ m and 3 mm, more particularly between 1 and 100 ⁇ m.
• the core of the fiber forms a solid structure. Alternatively, it can however define a hollow structure. This structure may also be porous or non-porous.
• a fiber is intended to ensure the holding of a mechanical part, to strengthen, and is thus distinguished from a tube or pipe for transporting a fluid.
• the fiber according to the invention is manufactured from at least two polymer matrices, one of which (the first polymeric matrix) forms the core and the other
• the second polymeric matrix forms the bark.
• Other polymeric matrices may also be used in the manufacture of the fiber according to the invention. It is thus possible to have a multilayer fiber containing only two layers (the heart and the bark) or more than two layers, in the case where one or more other layers are interposed between the heart and the bark and / or cover the bark.
• the first and / or second polymeric matrix contains at least one thermoplastic polymer, which may be a homopolymer or a block copolymer, alternate, statistical or gradient.
• the thermoplastic polymer may especially be chosen from:
• polyamides such as polyamide 6 (PA-6), polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 6.6 (PA-6.6), polyamide 4.6 (PA-4.6), polyamide 6.10 (PA-6.10) and polyamide 6.12 (PA-6.12), some of these polymers are especially sold by the company Arkema under the name Rilsan ® and preferred being those of fluid grade such as Rilsan ® AMNO TLD as well as copolymers, including block copolymers containing amide monomers and other monomers such as polytetramethylene glycol (PTMG) (Pebax ®); aromatic polyamides such as polyphthalamides;
• PTMG polytetramethylene glycol
• fluoropolymers chosen from:
• X 1 , X 2 and X 3 independently denote a hydrogen or halogen atom (in particular fluorine or chlorine), such as polyvinylidene fluoride (PVDF), preferably in ⁇ form, poly (trifluoroethylene) (PVF3), polytetrafluoroethylene (PTFE), copolymers of vinylidene fluoride with either hexafluoropropylene (HFP) or trifluoroethylene (VF3), or tetrafluoroethylene (TFE), or chlorotrifluoroethylene (CTFE), fluoroethylene / propylene copolymers (FEP), copolymers of ethylene with either fluoroethylene / propylene (FEP), or tetrafluoroethylene (TFE), or chlorotrifluoroethylene (CTFE); (ii) those comprising at least 50 mol% of at least one monomer of formula (II):
• PVDF polyvinylidene fluoride
• PVDF polyviny
• PPVE perfluoropropyl vinyl ether
• PEVE perfluoroethyl vinyl ether
• PMVE perfluoromethylvinyl ether
• PAEK polyaryletherketones
• PEEK polyetheretherketone
• PEKK polyetherketoneketone
• polyolefins such as polyethylene (PE), polypropylene (PP) and copolymers of ethylene and / or propylene (PE / PP) optionally functionalized; thermoplastic polyurethanes (TPU);
• PE polyethylene
• PP polypropylene
• TPU thermoplastic polyurethanes
• thermoplastic polymer (s) contained in the first polymeric matrix may or may not be chosen from the same family as, or even identical to, that or those contained in the second polymeric matrix.
• the first polymer matrix contains, in addition to the thermoplastic polymer mentioned above, nanotubes of at least one chemical element selected from the elements of columns IHa, IVa and Va of the periodic table.
• the polymer matrix advantageously comprises at least one polymer chosen from: PVDF, PA-II, PA-12, PEKK and PE.
• These nanotubes by their nature and their quantity, must be capable of providing thermal and / or electrical conduction. They may be based on carbon, boron, phosphorus and / or nitrogen (borides, nitrides, carbides, phosphides) and for example consisting of carbon nitride, boron nitride, boron carbide, boron, phosphorus nitride or carbon boronitride. Carbon nanotubes (hereinafter, CNTs) are preferred for use in the present invention.
• the nanotubes that can be used according to the invention can be single-walled, double-walled or multi-walled.
• the double-walled nanotubes can in particular be prepared as described by FLAHAUT et al in Chem. Com. (2003), 1442.
• the multi-walled nanotubes may themselves be prepared as described in WO 03/02456.
• the nanotubes usually have a mean diameter ranging from 0.1 to 200 nm, preferably from 0.1 to 100 nm, more preferably from 0.4 to 50 nm and better still from 1 to 30 nm and advantageously a length of from 0 to 100 nm. , 1 to 10 ⁇ m.
• Their length / diameter ratio is preferably greater than 10 and most often greater than 100.
• Their specific surface area is for example between 100 and 300 m 2 / g and their apparent density may especially be between 0.05 and 0.5 g / cm 3 and more preferably between 0.1 and 0.2 g / cm 3 .
• the multiwall nanotubes may for example comprise from 5 to 15 sheets (or walls) and more preferably from 7 to 10 sheets. These nanotubes may or may not be processed.
• crude carbon nanotubes is especially commercially available from Arkema under the trade name Graphistrength® ® C100.
• nanotubes may be purified and / or treated (for example oxidized) and / or milled and / or functionalized before being used in the process according to the invention.
• the grinding of the nanotubes may in particular be carried out cold or hot and be carried out according to known techniques used in devices such as ball mills, hammers, grinders, knives, gas jet or any other system. Grinding capable of reducing the size of the entangled network of nanotubes. It is preferred that this grinding step is performed according to a gas jet grinding technique and in particular in an air jet mill.
• the purification of the crude or milled nanotubes can be carried out by washing with a sulfuric acid solution, so as to rid them of any residual mineral and metallic impurities originating from their preparation process.
• the weight ratio of the nanotubes to the sulfuric acid may especially be between 1: 2 and 1: 3.
• the purification operation may also be carried out at a temperature ranging from 90 to 120 ° C., for example for a period of 5 to 10 hours. This operation may advantageously be followed by rinsing steps with water and drying the purified nanotubes.
• the nanotubes may alternatively be purified by high temperature heat treatment, typically greater than 1000 0 C.
• the oxidation of the nanotubes is advantageously carried out by putting them in contact with a solution of sodium hypochlorite containing from 0.5 to 15% by weight of NaOCl and preferably from 1 to 10% by weight of NaOCl, for example in a weight ratio of nanotubes to
• Sodium hypochlorite ranging from 1: 0.1 to 1: 1.
• the oxidation is advantageously carried out at a temperature of less than 60 ° C. and preferably at ambient temperature, for a duration ranging from a few minutes to 24 hours. This oxidation operation may advantageously be followed by filtration and / or centrifugation, washing and drying steps of the oxidized nanotubes.
• the functionalization of the nanotubes can be carried out by grafting reactive units such as vinyl monomers on the surface of the nanotubes.
• the constituent material of the nanotubes is used as a radical polymerization initiator after having been subjected to a heat treatment at more than 900 ° C., in an anhydrous and oxygen-free medium, which is intended to eliminate the oxygenated groups from its surface. It is thus possible to polymerize methyl methacrylate or hydroxyethyl methacrylate on the surface of carbon nanotubes in order, in particular, to facilitate their dispersion. in PVDF or polyamides.
• the functionalization of the nanotubes included in the bark of the fiber can improve their attachment to the core of the fiber.
• Crude nanotubes are preferably used in the present invention, that is to say nanotubes which are neither oxidized nor purified nor functionalized and have undergone no other chemical and / or thermal treatment.
• the nanotubes may represent from 0.1 to 30% by weight, preferably from 0.5 to 10% by weight, and even more preferably from 1 to 5% by weight, relative to the weight of the core or the bark. container.
• the present invention also relates to a method of manufacturing a fiber as described above, as well as the fiber obtainable by this method.
• This method comprises a step of coextrusion of the first and second polymer matrices, through a die having an opening which comprises a first outlet port fed by said first polymeric matrix and having the cross-sectional shape of said core, and a second outlet port fed by said second polymeric matrix and having the cross-sectional shape of said bark.
• Such a coextrusion process is well known to those skilled in the art. It usually involves a preliminary stage of introduction, then mixing, in a mixing device, for example in an extruder (in particular a co-rotating twin-screw extruder) or a BUSS®-type co-kneader, respective constituents of the first and second polymer matrices.
• a mixing device for example in an extruder (in particular a co-rotating twin-screw extruder) or a BUSS®-type co-kneader, respective constituents of the first and second polymer matrices.
• thermoplastic polymers are generally introduced in the form of granules or in the form of a powder in the kneading device.
• the nanotubes can be introduced into the same feed hopper as the polymer or in a separate hopper.
• the polymer matrices used according to the invention may also contain at least one adjuvant chosen from plasticizers, anti-oxygen stabilizers, light stabilizers, dyes, anti-shock agents and antistatic agents (other than nanotubes). ), flame retardants, lubricants, and mixtures thereof.
• the polymer matrix containing the conductive nanotubes contains at least one dispersant, intended to improve the dispersion of the nanotubes in this matrix.
• This may be a block copolymer as described in the application WO 2005/108485, that is to say a copolymer comprising at least one block 1 bearing ionic or ionizable functions, resulting from the polymerization of a monomer.
• M1 representing at least 10% by weight of block 1 (such as (meth) acrylic acid or maleic anhydride) and at least one monomer M2 (such as a (meth) acrylate or a styrene derivative) , and optionally at least one block 2 compatible with the thermoplastic polymer of the polymeric matrix conductive, if block 1 is not.
• the dispersant may be a plasticizer which is then advantageously introduced into the kneading device upstream, or into the melting zone of the thermoplastic polymer.
• the plasticizer, the thermoplastic polymer and the nanotubes may be introduced simultaneously or successively into the same feed hopper of the mixer. It is generally preferred to introduce all the plasticizer into this hopper.
• the aforementioned materials can be introduced successively, in any order, either directly into the hopper, or into a suitable container where they are homogenized before being introduced into the hopper.
• the polymer is predominantly in the form of powder, rather than granules.
• the Applicant has in fact demonstrated that this results in a better dispersion of the nanotubes in the polymer matrix, and a better conductivity of the resulting conductive matrix.
• This embodiment of the invention is well suited to solid plasticizers. These can optionally be introduced into the feed hopper of the mixer in the form of pre-composite with nanotubes.
• pre-composite containing 70% by weight of cyclized poly (butylene terephthalate) plasticizer and 30% by weight of multi-walled nanotubes, is for example commercially available from the company ARKEMA under the trade name Graphistrength® C M12-30.
• the nanotubes and the plasticizer can be introduced into the hopper or the aforementioned container in the form of precomposite.
• a pre-composite may for example be obtained by a process involving: 1-bringing a plasticizer in liquid form into contact, possibly in the molten state or in solution in a solvent, with the powdered nanotubes, for example by dispersion or direct introduction by pouring the plasticizer into the nanotube powder (or the opposite), by drip introduction of the plasticizer into the powder or by nebulization of the plasticizer by means of a sprayer on the nanotube powder , and
• the first step above can be carried out in conventional synthesis reactors, blade mixers, fluidized bed reactors or in Brabender mixers, Z-arm mixer or extruder. It is generally preferred to use a conical mixer, for example of the HOSOKAWA Vrieco-Nauta type, comprising a rotating screw rotating along the wall of a conical tank.
• a conical mixer for example of the HOSOKAWA Vrieco-Nauta type, comprising a rotating screw rotating along the wall of a conical tank.
• a pre-composite may be formed from the liquid plasticizer and the thermoplastic polymer before mixing with the nanotubes.
• the conductive polymer matrix obtained is introduced into a coextrusion die, with the other polymer matrix not containing nanotubes.
• This die may have first and second exit orifices of any shape and arrangement, respectively for the first and second polymeric matrixes, provided that the second polymeric matrix at least partially forms a bark around the first polymeric matrix.
• the first and second orifices are concentric.
• the second orifice may in this case be disposed over the entire periphery of the first orifice or on only a portion thereof.
• the second orifice may be partially disposed at the periphery of the first orifice and partially through the first orifice.
• the first orifice can thus take the form of two half-moons, for example.
• the core of the fiber according to the invention can take a shape, in cross section, circular, elliptical, square, rectangular, triangular or multilobal.
• the use of a multilobal shape makes it possible, in particular during the subsequent weaving of the fibers, to connect the surface lines of the fibers.
• the method according to the invention may further comprise an additional step of stretching the obtained fibers at a temperature above the glass transition temperature (Tg) of the thermoplastic polymer of the non-conductive matrix and optionally greater than the Tg of the thermoplastic polymer of the conductive polymeric matrix and preferably less than the melting temperature of the thermoplastic polymer of the non-conductive matrix.
• Tg glass transition temperature
• This stretching step may also optionally be conducted at a temperature above the melting point of the thermoplastic polymer of the conductive polymer matrix, in order to improve its conductive properties.
• the stretching step described in US Pat. No. 6,331,265, which is incorporated herein by reference, makes it possible to orient the nanotubes and the polymer substantially in the same direction, along the axis of the fiber, and thus to improve the mechanical properties of the latter, in particular its tensile modulus (Young's modulus) and its toughness (breaking point).
• the draw ratio defined as the ratio of the length of the fiber after drawing to its length before drawing, may be from 1 to 20, preferably from 1 to 10, inclusive. Stretching can be done in one go, or several times, allowing the fiber to relax slightly between each stretch.
• This stretching step is preferably conducted by passing the fibers through a series of rolls having different rotational speeds, those which unroll the fiber rotating at a lower speed than those receiving it.
• the fibers can be passed through ovens arranged between rollers, either use heated rollers, or combine these two techniques.
• the multilayer conductive fibers obtained by this method are intrinsically conductive, i.e. the conductive polymer matrix has a resistivity which may be less than 10 5 ohm. cm at room temperature, the electrical conductivity of these fibers can be further improved by heat treatments.
• the multilayer conductive fibers according to the invention can be used for the manufacture of nose, wings or cockles of rockets or airplanes; off-shore flexible armor; automotive bodywork components, engine chassis or automobile support parts; automotive seat coverings; structural elements in the field of buildings or bridges and roadways; packaging and antistatic textiles, in particular antistatic curtains, antistatic clothing (for example, safety or clean room) or materials for the protection of silos or the packaging and / or transport of powders or granular materials; furnishing items, including clean room furniture; filters; electromagnetic shielding devices, in particular for the protection of electronic components; heated textiles; conductive cables; sensors, in particular deformation sensors or mechanical stresses; electrodes; hydrogen storage devices; or biomedical devices such as sutures, prostheses or catheters.
• the manufacture of these composite parts can be carried out according to various processes, generally involving a step of impregnating the fibers with a polymeric composition containing at least one thermoplastic, elastomeric or thermosetting material.
• This impregnation stage may itself be carried out according to various techniques, depending in particular on the physical form of the composition used (pulverulent or more or less liquid).
• the impregnation of the fibers is preferably carried out according to a fluidized bed impregnation process, in which the polymeric composition is in the form of powder.
• the polymeric impregnating matrix comprises at least one of the thermoplastic materials used for the manufacture of the multilayer conductive fibers according to the invention.
• the manufacture of the finished part comprises a consolidation step of the polymeric composition, which is, for example, melted locally to create zones for fixing the fibers. between them and / or secure the fiber ribbons in the filament winding process.
• a film from the impregnating composition in particular by means of an extrusion or calendering process, said film having for example a thickness of about 100 ⁇ m, and then of placed between two mats of fibers according to the invention, the assembly then being hot pressed to allow the impregnation of the fibers and the manufacture of the composite.
• the multilayer fibers according to the invention can be woven or knitted, alone or with other fibers, or used, alone or in combination with other fibers, for the manufacture of felts or nonwoven materials .
• materials constituting these other fibers include, but are not limited to: - stretched polymer fibers, based in particular: polyamide such as polyamide 6 (PA-6), polyamide 11 (PA-II), polyamide 12 (PA-12), polyamide 6.6 (PA-6.6), polyamide 4.6 (PA-4.6), polyamide 6.10 (PA-6.10) or polyamide 6.12 (PA-6.12), of polyamide / polyether block copolymer (Pebax ® ), high density polyethylene, polypropylene or polyester such as polyhydroxyalkanoates and polyesters marketed by Du Pont under the trade name Hytrel ® ;
• the invention therefore also relates to a composite material comprising multilayer composite fibers as described above, bonded together by weaving or using a polymeric matrix.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Multicomponent Fibers (AREA)
• Artificial Filaments (AREA)

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• 2009
  • 2009-05-27 FR FR0953507A patent/FR2946176A1/fr not_active Withdrawn
• 2010
  • 2010-05-27 JP JP2012512437A patent/JP2012528253A/ja not_active Withdrawn
  • 2010-05-27 WO PCT/FR2010/051026 patent/WO2010136729A1/fr active Application Filing
  • 2010-05-27 US US13/320,959 patent/US20120077403A1/en not_active Abandoned
  • 2010-05-27 CN CN2010800231398A patent/CN102449211A/zh active Pending
  • 2010-05-27 EP EP10728834A patent/EP2435608A1/fr not_active Withdrawn
  • 2010-05-27 KR KR1020117028252A patent/KR20120017436A/ko not_active Application Discontinuation
• 2011
  • 2011-11-08 IL IL216216A patent/IL216216A0/en unknown

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