WO2024114984A1

WO2024114984A1 - Core-coated textile reinforcing element, staple fibre and product reinforced by at least one staple fibre

Info

Publication number: WO2024114984A1
Application number: PCT/EP2023/077624
Authority: WO
Inventors: Lilian MEDINA; Magaly BROUSSEAU; Sébastien Noel; Romain LIBERT; Sandra GUELON
Original assignee: Compagnie Generale Des Etablissements Michelin
Priority date: 2022-11-28
Filing date: 2023-10-05
Publication date: 2024-06-06
Also published as: FR3142496A1

Abstract

The invention relates to a core-coated textile reinforcing element which comprises: at least one or more textile filaments and/or a plurality of natural textile or organic polymer fibres. The core-coated textile reinforcing element is obtained by a method comprising a step of manufacturing the coated textile reinforcing element, in which step a textile reinforcing element is passed into a bath of an adhesive composition, the quantity of dry matter resulting from the bath of the adhesive composition representing from 10 to 20% by dry weight of the textile reinforcing element.

Description

Title: Core-glued textile reinforcement element, short fiber and product reinforced with at least one short fiber

[001] The field of the present invention is that of core-glued textile reinforcing elements, short fibers obtained from cutting core-glued textile reinforcing elements and composites comprising an elastomeric material and short fibers embedded in this elastomeric material. The present invention relates more particularly to such composites forming reinforced products chosen from conveyor belts, transmission belts, tracks, tires for pneumatic or non-pneumatic wheels.

[002] We know from the state of the art, in particular from EP1792755, short carbon fibers glued with an aqueous adhesive composition based on RFL (Resorcinol - Formaldehyde - Latex) to reinforce an elastomeric matrix. The coating of the fibers must be such as to prevent any clumping of the fibers during the adhesive processing step, clumping being defined as more than five individual chopped fibers sticking together along at least part of the longitudinal axis of the fiber and after adding the chopped fibers to the elastomer mixture in the mixer, the mixture must be sufficient to prevent further clumping of the fibers in the elastomer.

[003] We also know from the state of the art, in particular from EP 1349889, a process for sizing carbon fibers to the core to reinforce an elastomeric matrix in which the fiber is twisted and then integrated into continuous reinforcement.

[004] The disadvantage of carbon fibers is, on the one hand, that they are easily damaged during the textile process and, on the other hand, they have low elongation at breakage. Finally, carbon fibers are relatively expensive, which limits their use in pneumatic applications.

[005] However, it is desirable to find new core-glued reinforcing elements with an elongation at break that is sufficiently high and industrially achievable, making it possible to guarantee good reinforcement/elastomeric matrix adhesion.

[006] The aim of the invention is to provide a core-glued textile reinforcement element meeting this objective.

[007] The subject of the invention is a core-glued textile reinforcing element which comprises: at least one or more textile filaments and/or several natural or organic polymeric textile fibers; in which the glued textile reinforcing element is obtained by a process comprising a step of manufacturing the glued textile reinforcing element in which a textile reinforcing element is passed through a bath of adhesive composition, the quantity of material dry from the bath of the adhesive composition representing 9.6 to 20% by weight dry textile reinforcing element.

[008] The Applicant notes that the core-glued reinforcing element obtained by the core-gluing process described below has a quantity of dry matter from the bath of the adhesive composition having 9.6 to 20% in dry weight of textile reinforcing element which is much greater than a reinforcing element glued using a conventional gluing process. The compounds mentioned in the description may be of fossil or biosourced origin. In the latter case, they can be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass. In the same way, the compounds mentioned can also come from the recycling of materials already used, that is to say they can be, partially or totally, from a recycling process, or even obtained from materials raw materials themselves resulting from a recycling process. This concerns in particular filaments, fibers, polymers, plasticizers, fillers, etc.

[009] A filament is a unitary element of very great length and continuous generally obtained by spinning a molten material. It can be either artificial or synthetic.

[010] Preferably, each filament and/or each fiber is chosen from polyester filaments and fibers, polyamide filaments and fibers, polyketone filaments and fibers, polyurethane filaments and fibers, polyurethane filaments and fibers, and acrylic fibers, polyolefin filaments and fibers, polyetheretherketone filaments and fibers and assemblies of these filaments and fibers, preferably from polyester filaments and fibers, polyester filaments and fibers polyamide and the assemblies of these filaments and these fibers and more preferably the filaments and the organic synthetic fibers are filaments and fibers of polyester or polyamide such as nylons PA4.6, PA56, PA6, PA6.6 and also PA6 .10.

[011] By definition, a textile reinforcing element is an assembly of these filaments and these fibers. Each reinforcing element is impregnated with a composition ensuring the cohesion of these filaments and these fibers with each other and making it possible to avoid fraying of each reinforcing element.

[012] Mention will be made of adhesive compositions of the RFL type (Resorcinol - Formaldehyde - Latex) but also adhesive compositions such as described in WO201 5118041. [013] Preferably, each reinforcing element can also be impregnated with a preadhesive of an aqueous composition, in particular for fibers and/or filaments having a poor affinity with RFL type adhesive compositions. This pre-adhesion step is carried out upstream of the step of manufacturing the core-glued textile reinforcing element. Examples include preadherents containing epoxy compounds and isocyanate compounds.

[014] The quantity of adhesive composition is measured by chemical attack, either by attack of the adhesive composition or by attack of the fiber.

[015] For polyamides, the chemical attack is carried out by attacking the fiber with a hot acid solution. The fiber is thus destroyed and the residue consisting of the adhesive composition is recovered and weighed. The weight of the adhesive composition is determined by relating the weight of the residue to the weight of the unsized dry fiber.

[016] For other fibers such as polyester, polyurethane polyketone, acrylic, polyolefin or polyetheretherketone fibers, the chemical attack is carried out by attacking the adhesive composition with an acid oxidizing solution. The adhesive composition as well as the size and pre-adhesion are destroyed.

[017] The residue consisting of the fibers is recovered and weighed. The determination of the weight of the adhesive composition is obtained by weighing the fibers before and after attack on the adhesive composition, correcting the result obtained by the quantity of sizing and pre-adhesion deposited on the fiber.

[018] The quantity of sizing and preadhesion deposited on the fiber can be determined experimentally by attacking the unbleached fiber.

[019] Advantageously, the core-glued textile reinforcing element is made up of: at least one or more textile filaments and/or several natural or organic polymeric textile fibers; in which the glued textile reinforcing element is obtained by a process comprising a step of manufacturing the glued textile reinforcing element in which a textile reinforcing element is passed through a bath of adhesive composition, the quantity of material dry from the bath of the adhesive composition representing 9.6 to 20% by dry weight of textile reinforcing element.

[020] Thus according to this preferred embodiment, the reinforcing element consists solely of one or more textile filaments and/or several natural or organic polymeric textile fibers glued to the core with an adhesive composition without other metallic constituent. Consisting solely of one or more textile filaments and/or several natural or organic polymeric textile fibers means that there are no metal wires in the reinforcing element.

[021] By filament and/or polyester fiber, we recall that it is a set of filaments made up of linear macromolecules formed of groups linked together by ester bonds. Polyesters are manufactured by polycondensation, by esterification between a dicarboxylic acid or one of its derivatives, a diol. For example, polyethylene terephthalate can be manufactured by polycondensation of terephthalic acid and ethylene glycol. Among the known polyesters, we can cite polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polypropylene terephthalate (PPT) or polypropylene naphthalate (PPN).

[022] By filament and/or fiber of aromatic polyamide or aromatic copolyamide, we recall in a well-known manner that it is a set of filaments made up of linear macromolecules formed of aromatic groups linked together by amide bonds of which at least 85% are directly linked to two aromatic nuclei, and more particularly to poly (p-phenylene terephthalamide) (or PPTA) fibers, manufactured for a very long time from optically anisotropic spinning compositions. Among the aromatic polyamides or aromatic copolyamides, mention may be made of polyarylamides (or PAA, notably known under the trade name Ixef from the company Solvay), poly(metaxylylene adipamide), polyphthalamides (or PPA, notably known under the trade name Amodel from the company Solvay), amorphous semi-aromatic polyamides (or PA 6-3T, notably known under the trade name Trogamid from the company Evonik), meta-aramides (or poly(metaphenylene isophthalamide or PA MPD-I, notably known under the trade name Nomex from the company Du Pont de Nemours) or para-aramids (or poly(paraphenylene terephthalamide or PA PPD-T in particular known under the trade name Kevlar from the company Du Pont de Nemours or Twaron from the company Teijin).

[023] By aliphatic polyamide filament and/or fiber is meant a set of filaments consisting of linear macromolecules of polymers or copolymers containing amide functions which do not have aromatic rings and which can be synthesized by polycondensation between a carboxylic acid and an amine . Among the aliphatic polyamides, mention may be made of nylons PA4.6, PA6, PA6.6 or even PA6.10, and in particular Zytel from the company DuPont, Technyl from the company Solvay or Rilsamid from the company Arkema.

[024] Advantageously, the titer of the aliphatic polyamide filament and/or fiber ranges from 7 to 660 tex, preferably from 50 to 440 tex, more preferably from 90 to 220 tex.

[025] The density (or linear mass) of each filament and/or fiber is determined according to the ASTM D1423 standard. The title is given in tex (mass in grams of 1000 m of product - reminder: 0.111 tex equal to 1 denier). The density of reinforcing elements in the composite is the number of reinforcing elements taken over a decimeter of the composite in the direction perpendicular to the direction in which the reinforcing elements extend parallel to each other.

[026] In one embodiment, advantageously, the organic polymeric filaments and fibers are chosen from polyester, aromatic polyamide or copolyamide, aliphatic polyamide and preferably from polyester filaments and fibers such as PET or polyamide such as nylons PA4.6, PA56, PA6, PA6.6 and PA6.10.

[027] In another embodiment, advantageously, the natural filaments and fibers are chosen from natural cellulosic fibers, linen, hemp, cotton, sisal, kenaf, bamboo, jute, coconut.

[028] Preferably, the quantity of dry material resulting from the bath of the adhesive composition represents 10 to 20% by dry weight of textile reinforcing element and more preferably 10 to 15% by dry weight of textile reinforcing element . Advantageously, the weight of adhesive composition is greater than or equal to 70 g/kg of reinforcing element.

[029] Preferably, the weight of adhesive composition is greater than or equal to 80 g/kg of reinforcing element and preferably greater than or equal to 100 g/kg of reinforcing element.

[030] More preferably, when the organic polymeric filaments and fibers are chosen from polyester, the weight of adhesive composition is greater than or equal to 100g/kg.

[031] More preferably, when the organic polymeric filaments and fibers are chosen from nylons and preferably nylon 66, the weight of adhesive composition is greater than or equal to 120 g/kg.

[032] Advantageously, the weight of adhesive composition is less than or equal to 250 g/kg of reinforcing element and preferably less than or equal to 200 g/kg of reinforcing element. reinforcement. Indeed, too large a layer of adhesive composition reduces the properties of fiber mixtures, and is often an indication of “surplus” of adhesive composition on the surface.

[033] In one embodiment, the textile reinforcing element comprises a single multifilament strand.

[034] Preferably, in this embodiment, the textile reinforcing element is made up of a single multifilament strand.

[035] In another embodiment, each textile reinforcement element comprises several multifilament strands.

[036] Advantageously, the adhesive composition is based on at least one phenol-aldehyde resin based on at least: an aldehyde; a polyphenol comprising one or more aromatic ring(s), it being understood that: in the case of a single aromatic ring, the latter carries two or three hydroxyl functions in the meta position relative to the other or relative to each other, the remainder of the aromatic ring being unsubstituted; in the case of several aromatic nuclei, at least two of them each carry two or three hydroxyl functions in the meta position relative to each other or to each other, it being understood that the two positions in ortho of at least one of these hydroxyl functions are unsubstituted. [037] By “meta position relative to each other”, we mean that the hydroxyl functions are carried by carbons of the aromatic ring separated from each other by a single other carbon of the aromatic ring.

[038] By “in the ortho position of a function”, we mean the position occupied by the carbon of the aromatic ring immediately adjacent to the carbon of the aromatic ring carrying the function.

[039] By “link” of a nucleus, we mean an atom constituting the skeleton of the nucleus. So, for example, a benzene ring has six members, each member consisting of a carbon atom. In another example, a furan nucleus has five members, with four members each consisting of a carbon atom and the remaining member consisting of an oxygen atom.

[040] “CHO” represents the aldehyde function.

[041] “CH2OH” represents the hydroxymethyl function. [042] By “aromatic polyphenol” is meant an aromatic compound comprising at least one benzene ring carrying more than one hydroxyl function.

[043] By “resin based on”, it should be understood that the resin comprises the mixture and/or the reaction product of the different basic constituents used for this resin as defined above and that this resin is only based on the constituents based on the composition.

[044] Very preferably, the adhesive composition is aqueous. By aqueous, we mean that the water content of the adhesive composition is greater than or equal to 50% by weight. The use of water as a solvent makes the adhesive composition easily usable in industrial conditions and at reduced cost.

[045] Aldehyde compound

[046] An essential constituent of the adhesive composition is a compound comprising at least one aldehyde.

[047] In accordance with the invention, the adhesive composition is based on at least one (that is to say one or more) aldehyde.

[048] In one embodiment, the aldehyde is formaldehyde.

[049] In another embodiment, the aldehyde is an aromatic aldehyde carrying at least one aldehyde function.

[050] Advantageously in this embodiment, the aromatic aldehyde carries at least two aldehyde functions.

[051] Preferably, the aromatic ring of the aromatic aldehyde is a benzene ring.

[052] More preferably, the aromatic aldehyde is chosen from the group consisting of 1,2-benzene-dicarboxaldehyde, 1,3-benzene-dicarboxaldehyde, 1,4-benzene-dicarboxaldehyde, 2-hydroxybenzene-1 ,3,5-tricarbaldehyde and mixtures of these compounds and preferably 1,4-benzene-dicarboxaldehyde.

[053] Polyphenol compound

[054] Another essential constituent of the adhesive composition is a polyphenol comprising one or more aromatic ring(s). The aromatic polyphenol comprises at least one aromatic nucleus carrying at least two hydroxyl functions in the meta position relative to each other, the two ortho positions of at least one of the hydroxyl functions being unsubstituted.

[055] According to the invention, the aromatic polyphenol may be, in one embodiment, a simple molecule of aromatic polyphenol comprising one or several aromatic nuclei, at least one of these aromatic nuclei, or even each aromatic nucleus, carrying at least two hydroxyl functions in meta position relative to each other, the two ortho positions of at least one of the functions hydroxyl being unsubstituted.

[056] In a preferred embodiment, the aromatic ring of the aromatic polyphenol carries three hydroxyl functions in meta position relative to each other.

[057] Preferably, the two ortho positions of each hydroxyl function are unsubstituted. By this we mean that the two carbon atoms located on either side (in the ortho position) of the hydroxylated carbon atom (i.e., carrying the hydroxyl function) carry a simple hydrogen atom.

[058] Even more preferably, the rest of the aromatic ring of the aromatic polyphenol is unsubstituted. By this we mean that the other carbon atoms of the rest of the aromatic ring (those other than the carbon atoms carrying hydroxyl functions) carry a single hydrogen atom.

[059] In one embodiment, the aromatic polyphenol comprises several aromatic nuclei, at least two of them each carrying at least two hydroxyl functions in the meta position relative to each other, the two positions ortho of at least one of the hydroxyl functions of at least one aromatic ring being unsubstituted.

[060] In a preferred embodiment, at least one of the aromatic nuclei of the aromatic polyphenol carries three hydroxyl functions in the meta position relative to each other.

[061] Preferably, the two ortho positions of each hydroxyl function of at least one aromatic ring are unsubstituted.

[062] Even more preferably, the two ortho positions of each hydroxyl function of each aromatic ring are unsubstituted.

[063] Advantageously, the or each aromatic ring of the aromatic polyphenol is a benzene ring.

[064] As an example of an aromatic polyphenol comprising a single aromatic nucleus, we can cite in particular resorcinol and phloroglucinol, as a reminder of the structural formulas (IV) and (V) respectively:

[065] As examples, in the case where the aromatic polyphenol comprises several aromatic nuclei, at least two of these aromatic nuclei, identical or different, are chosen from those of general formulas:

in which the symbols Z1, Z2, identical or different if there are several on the same aromatic nucleus, represent an atom (for example carbon, sulfur or oxygen) or a linking group by definition at least divalent, which connects at least these two aromatic rings to the rest of the aromatic polyphenol.

[066] Another example of aromatic polyphenol is 2, 2', 4,4'-tetrahydroxydiphenyl sulfide of the following structural formula (VII):

[067] Another example of aromatic polyphenol is 2, 2', 4,4'-tetrahydroxydiphenyl benzophenone of the following structural formula (VIII):

[068] We note that each compound VII and VIII is an aromatic polyphenol comprising two aromatic nuclei (of formulas Vl-c) each of which carries at least two (in this case two) hydroxyl functions in the meta position. one in relation to the other.

[069] Note that in the case of an aromatic polyphenol comprising at least one aromatic ring conforming to formula Vl-b, the two ortho positions of each hydroxyl function of at least one aromatic ring are unsubstituted. In the case of an aromatic polyphenol comprising several aromatic rings conforming to formula Vl-b, the two ortho positions of each hydroxyl function of each aromatic ring are unsubstituted.

[070] According to one embodiment of the invention, the aromatic polyphenol is chosen from the group consisting of resorcinol (IV), phloroglucinol (V), 2, 2', 4,4'- tetrahydroxydiphenyl sulfide (VII ), 2,2',4,4 -tetrahydroxybenzophenone (VIII), and mixtures of these compounds. In a particularly advantageous embodiment, the aromatic polyphenol is phloroglucinol.

[071] In one embodiment, the aromatic polyphenol A2 comprises a pre-condensed resin based on the aromatic polyphenol as described in any of these embodiments.

[072] This pre-condensed resin is advantageously based on:

• at least one aromatic polyphenol as defined above, and preferably chosen from the group consisting of resorcinol, phloroglucinol, 2,2',4,4'-tetrahydroxydiphenyl sulfide, 2, 2', 4,4 - tetrahydroxybenzophenone, and their mixtures; And

• at least one compound capable of reacting with the aromatic polyphenol comprising at least one aldehyde function and/or at least one compound capable of reacting with the aromatic polyphenol comprising at least two hydroxymethyl functions, and preferably an aromatic aldehyde comprising at least one aromatic nucleus carrying at least one aldehyde function.

[073] The compound capable of reacting with the aromatic polyphenol may be a compound A1 as defined above or any other aldehyde. Advantageously, said compound is chosen from the group consisting of an aromatic compound comprising an aromatic nucleus carrying at least two functions, one of these functions being a hydroxymethyl function, the other being an aldehyde function or a hydroxymethyl function, the formaldehyde, furfuraldehyde, 2,5-furanedicarboxaldehyde, 1,4-benzenedicarboxaldehyde, 1,3-benzenedicarboxaldehyde, 1,2-benzenedicarboxaldehyde and mixtures of these compounds. Very advantageously, when the compound capable of reacting with the aromatic polyphenol is an aromatic compound comprising an aromatic nucleus carrying at least two functions, one of these functions being a hydroxymethyl function, the other being an aldehyde function or a function hydroxymethyl, this compound is chosen from the group consisting of 5-(hydroxymethyl)-furfural, 2,5-di(hydroxymethyl)furan and mixtures of these compounds.

[074] Thus, in the pre-condensed resin based on aromatic polyphenol, the repeating unit meets the characteristics of the aromatic polyphenol defined previously with the exception that at least one of the carbon atoms of the aromatic ring, which was unsubstituted, is linked to another motive.

[075] Whatever the compound other than the aromatic polyphenol at the base of the pre-condensed resin, this pre-condensed resin is free of free formaldehyde. Indeed, even in the case where the pre-condensed resin is based on an aromatic polyphenol as described above and formaldehyde, the formaldehyde having already reacted with the aromatic polyphenol, the pre-condensed resin is devoid of free formaldehyde likely to be able to react with a compound A1 according to the invention in a subsequent step.

[076] The aromatic polyphenol A2 may also comprise a mixture of a free aromatic polyphenol molecule and a pre-condensed resin based on aromatic polyphenol, as described above. In particular, the aromatic polyphenol A2 may also comprise a mixture of phloroglucinol and a pre-condensed resin based on phloroglucinol.

[077] Process for manufacturing the core-glued reinforcing element according to the invention [078] We will now describe an example of a core-gluing process for a reinforcing element.

[079] During this process, the reinforcing element is a textile reinforcing element in PA 6.6 which is glued to the core with an aqueous adhesive composition based on RFL.

[080] We carry out an optional step of suction of the reinforcing element so as to open the filaments and/or fibers constituting it, then we carry out a step of bringing the textile reinforcing element into contact in a tray with an adhesive composition, the tray being equipped with two central bars machined in the shape of a dome so as to open the reinforcing element, in another step the reinforcing element is then scrolled through at least two other trays, each tray comprising an identical adhesive composition, each tray being equipped downstream with a “rabbit feet” type roller on which the reinforcing element is rolled so as to remove the excess adhesive composition, this step is followed by a step of drying the glued reinforcing element at a temperature ranging from 150 to 240°C and here at 220°C for 27 seconds.

[081] Short fiber according to the invention

[082] The invention also relates to a short fiber obtained by cutting the core-glued textile reinforcing element as described above, to a length comprised in a range ranging from 0.1 to 20 mm, and preferably from 0.4 to 10mm.

[083] By short fiber we mean a discontinuous fiber of reduced length. These can be either natural fibers or cut filaments.

[084] Advantageously, the diameter is included in a range ranging from 0.5 to 100 pm and preferably from 1 to 30 pm.

[085] Process for manufacturing the short fiber according to the invention

[086] The short fiber is obtained by cutting the textile reinforcing element glued to the core as described above.

[087] COMPOSITE ACCORDING TO THE INVENTION

[088] The invention also relates to an elastomer composite reinforced with at least one short fiber as described above, comprising an elastomer matrix in which the short fiber is embedded.

[089] The elastomer matrix is based on an elastomer composition comprising at least one elastomer and another constituent.

[090] Preferably, the elastomer composition comprises a diene elastomer. By elastomer or rubber (the two terms being synonymous) of the "diene" type, we generally mean an elastomer derived at least in part (ie a homopolymer or a copolymer) from diene monomers (monomers carrying two carbon-carbon double bonds , conjugated or not). [091] The elastomer compositions may contain a single diene elastomer or a mixture of several diene elastomers, the diene elastomer(s) being able to be used in combination with any type of synthetic elastomer other than diene, or even with polymers other than diene elastomers. elastomers, for example thermoplastic polymers.

[092] In a first embodiment preferably intended for pneumatic use, the elastomer composition comprises a diene elastomer chosen from the group consisting of polybutadienes (BR), ethylene butadiene rubber (EBR), natural rubber (NR ), synthetic polyisoprenes (IR), the different butadiene copolymers, the different isoprene copolymers, and mixtures of these elastomers.

[093] Such copolymers are more preferably chosen from the group consisting of butadiene-styrene copolymers (SBR), whether the latter are prepared by polymerization in emulsion (ESBR) or in solution (SSBR), copolymers of isoprene- butadiene (BIR), isoprene-styrene copolymers (SIR) and isoprene-butadiene-styrene copolymers (SBIR).

[094] In a second embodiment preferably intended for belt use, the elastomer composition comprises an elastomer chosen from the group consisting of TPU (thermoplastic urethane), PU (polyurethane), an elastomer of the ethylene alpha olefin type , a polychloroprene elastomer and mixtures of these elastomers, one or more other elastomers. The elastomer composition may also include one or more other components.

[095] Advantageously, the ethylene alpha olefin type elastomer is chosen from the group consisting of ethylene-propylene copolymers (EPM), ethylene-propylene-diene copolymers (EPDM) and mixtures of these copolymers.

[096] Preferably, the elastomer composition comprises a reinforcing filler. [097] When a reinforcing filler is used, any type of reinforcing filler known for its capacity to reinforce an elastomer composition usable for the manufacture of tires can be used, for example an organic filler such as carbon black, a reinforcing inorganic filler such as silica, or even a blend of these two types of filler, in particular a blend of carbon black and silica.

[098] All carbon blacks conventionally used in tires (so-called grade blacks) are suitable as carbon blacks. pneumatic). For example, we will particularly mention the reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades).

[099] In the case of using carbon blacks with an isoprene elastomer, the carbon blacks could for example already be incorporated into the isoprene elastomer in the form of a masterbatch (see for example applications WO 97/36724 or WO 99/16600).

[0100] As examples of organic fillers other than carbon blacks, mention may be made of functionalized polyvinylaromatic organic fillers as described in applications WO-A-2006/069792 and WO-A-2006/069793.

[0101]By “reinforcing inorganic filler”, must be understood in the present application, by definition, any inorganic or mineral filler (whatever its color and its origin (natural or synthetic), also called “white” filler, filler "clear" or even "non-black filler" as opposed to carbon black, capable of reinforcing on its own, without any other means than an intermediate coupling agent, an elastomer composition, in d other terms capable of replacing, in its reinforcing function, a conventional pneumatic grade carbon black. Such a filler is generally characterized, in a known manner, by the presence of hydroxyl groups (-OH) on its surface.

[0102] The physical state in which the reinforcing inorganic filler is presented is irrelevant, whether in the form of powder, micro-beads, granules, beads or any other suitable densified form. Of course, the term reinforcing inorganic filler also means mixtures of different reinforcing inorganic fillers, in particular highly dispersible siliceous and/or aluminous fillers as described below.

[0103] As reinforcing inorganic fillers suitable in particular are mineral fillers of the siliceous type, in particular silica (SiO2), or of the aluminous type, in particular alumina (AI2O3). The silica used can be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET surface area as well as a CTAB specific surface area both less than 450 m2/g, preferably 30 to 400 m2/ g. As highly dispersible precipitated silicas (called "HDS"), we will cite for example the "Ultrasil" 7000 and "Ultrasil" 7005 silicas from the company Evonik, the "Zeosil" silicas 1165MP, 1135MP and 1115MP from the company Rhodia, the "Hi-Sil" EZ150G silica from the PPG company, "Zeopol" silicas 8715, 8745 and 8755 from the Huber company, high surface silicas specific as described in application WO 03/16837.

[0104]Finally, those skilled in the art will understand that as an equivalent filler to the reinforcing inorganic filler described in this paragraph, a reinforcing filler of another nature, in particular organic, could be used, since this reinforcing filler would be covered with an inorganic layer such as silica, or would have functional sites on its surface, in particular hydroxyl, requiring the use of a coupling agent to establish the connection between the filler and the elastomer.

[0105] Preferably, the level of total reinforcing filler (carbon black and/or reinforcing inorganic filler such as silica) is within a range of 5 to 120 phr, more preferably 5 to 100 phr and even more preferably 5 at 90 pce.

[0106] Carbon black can advantageously constitute the only reinforcing filler or the majority reinforcing filler. Of course, you can use a single carbon black or a blend of several carbon blacks of different ASTM grades. Carbon black can also be used in blending with other reinforcing fillers and in particular reinforcing inorganic fillers as described above, and in particular silica.

[0107] When an inorganic filler (for example silica) is used in the rubber composition, alone or in combination with carbon black, its level is included in a range of 0 to 100 phr, preferably from 0 to 70 phr, in particular also from 5 to 70 phr, and even more preferably this proportion varies from 5 to 50 phr, particularly from 5 to 40 phr.

[0108] Preferably, the elastomer composition comprises various additives.

[0109] The rubber compositions may also include all or part of the usual additives usually used in elastomer compositions intended for the manufacture of tires, such as for example plasticizers or extender oils, whether the latter are aromatic in nature. or non-aromatic, pigments, protective agents such as anti-ozone waxes, chemical antiozonants, anti-oxidants, anti-fatigue agents or even adhesion promoters.

[0110] Preferably, the elastomer composition comprises a crosslinking system.

[0111] In the first embodiment preferably intended for use tire, track or conveyor belt, the elastomer composition includes a vulcanization system.

[0112] The vulcanization system comprises a sulfur donor agent, for example sulfur.

[0113] Preferably, the vulcanization system comprises vulcanization activators such as zinc oxide and stearic acid.

[0114] Preferably, the vulcanization system comprises a vulcanization accelerator and/or a vulcanization retarder.

[0115]Advantageously, the composite is such that the elastomer matrix is based on an elastomer composition comprising a crosslinking system comprising a level of molecular sulfur ranging from 1 to 5 phr.

[0116] Very advantageously, the molecular sulfur content of the crosslinking system of the elastomer composition is greater than or equal to 1.5 phr.

[0117] The sulfur level is measured by elemental analysis, using the Thermo Scientific Flash 2000 microanalyzer. The analysis includes a step of combustion of the sample then a step of separation of the compounds formed.

[0118] Approximately 1 mg of sample is introduced into the micro-analyzer, where it undergoes flash combustion at 1000° C. under oxygen. The gases formed are then oxidized using excess oxygen and a tungstic anhydride catalyst. A reduction step by passing over copper then makes it possible to trap the excess oxygen, and to reduce the nitrogen oxides to N2 as well as the sulphites to sulfur dioxide SO2. The water is trapped and the N2, CO2, SO2 compounds formed are then separated on a chromatographic column and then detected by a catharometer. Quantification of total sulfur is carried out by measuring the area of the SO2 peak, after calibration with standards.

[0119]All of the vulcanization accelerators, retarders and activators are used at a preferential rate within a range of 0.5 to 15 phr. The vulcanization activator(s) is(are) used at a preferential rate comprised in a range of 0.5 and 12 phr.

[0120] The crosslinking system itself is preferably based on sulfur and a primary vulcanization accelerator, in particular an accelerator of the sulfenamide type. To this vulcanization system are added various secondary accelerators or known vulcanization activators such as zinc oxide, stearic acid, guanidic derivatives (in particular diphenylguanidine), etc. [0121] Any compound capable of acting as an accelerator of vulcanization of diene elastomers in the presence of sulfur can be used as accelerator (primary or secondary), in particular accelerators of the thiazole type as well as their derivatives, accelerators of the thiuram type, and of zinc dithiocarbamate type. These accelerators are more preferably chosen from the group consisting of 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide (abbreviated "CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide (abbreviated "DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide (abbreviated "TBBS"), N-ter-butyl-2-benzothiazyl sulfenimide (abbreviated "TBSI"), zinc dibenzyldithiocarbamate (abbreviated abbreviated “ZBEC”) and mixtures of these compounds. Preferably, a primary accelerator of the sulfenamide type is used.

[0122]In the second embodiment preferably intended for belt use, the crosslinking system is substantially free of sulfur, and advantageously comprises a peroxide, preferably an organic peroxide. Advantageously, the peroxide level ranges from 0.5 to 8 phr. Advantageously, the crosslinking system comprises a co-crosslinking agent, preferably sulfur or triallylcyanurate. Advantageously, the level of co-crosslinking agent ranges from 0.5 to 5 phr.

[0123] REINFORCED PRODUCT ACCORDING TO THE INVENTION

[0124]The invention also relates to a reinforced product comprising at least one composite as described above. The reinforced product of the invention is advantageously chosen from conveyor belts, transmission belts, tracks, pneumatic or non-pneumatic wheel tires.

[0125] The invention will be better understood on reading the description which follows, given solely by way of non-limiting example and made with reference to the drawings in which:

- Figure 1 is a diagram of a composite F according to the invention;

- Figure 2 is a scanning electron microscope view of the composite F1 according to the invention; And

- Figure 3 is an enlargement of a sectional view of a core-glued reinforcing element 10-1 according to the invention.

[0126] EXAMPLE OF COMPOSITE ACCORDING TO THE INVENTION

[0127] Figure 1 shows a composite according to the invention and designated by the general reference F. The composite F comprises at least one short fiber E, in this case several short fibers E, embedded in the polymer matrix M.

[0128] In Figure 1, the polymer matrix M, the short fibers E are shown in a reference X, Y, Z in which the direction Y is the radial direction and the directions X and Z are the axial and circumferential directions. In Figure 1, the composite F comprises several short fibers E arranged randomly within the composite and collectively embedded in the polymer matrix M.

Here, the polymer matrix M is an elastomeric matrix based on an elastomeric composition.

[0129] In Figure 2, we observe an enlargement in section using an electron scanning microscope of a composite F1 according to the invention as described in Table 2 below with the white areas of the gluing at the core of short fiber E.

[0130] EXAMPLE OF A CORE-GLUED REINFORCEMENT ELEMENT ACCORDING TO THE INVENTION [0131] Figure 3 is an enlargement of a sectional view of a 10-1 core-glued reinforcing element according to the invention.

[0132] This reinforcing element 10-1 will be described in Table 1 below.

[0133]Of course, the invention relates to the objects described above, namely the reinforced product such as the conveyor belt, the transmission belt, the caterpillar, the tire for a pneumatic or non-pneumatic wheel comprising it, both in the state raw (before crosslinking) than in the cooked state (after crosslinking).

[0134] COMPARATIVE TESTS

[0135]The different reinforcing elements described below are brought together in Table 1 below as well as the corresponding results of % by dry weight of adhesive composition.

[0136]The witness is a PA 6.6 reinforcing element glued by a well-known process of soaking the PA 6.6 fiber in a bath of an aqueous adhesive composition based on RFL, glues known under the name “RFL” (for resorcinol-formaldehyde-latex), as for example described in EP2006341. These RFL adhesives comprise in a well-known manner a thermosetting phenolic resin, obtained by the condensation of resorcinol with formaldehyde, and one or more diene elastomer latexes in aqueous solution.

[0137] The reinforcing element 10-1 is a reinforcing element in PA 6.6 140 tex glued by a core gluing process as described above in a bath of an aqueous adhesive composition based on RFL. [0138] The reinforcing element 10-T is a reinforcing element in PA 6.6 140 tex glued by a core gluing process as described above in a bath of an aqueous adhesive composition based on PT, the PT glue being chosen from the adhesive compositions as described in WO2015118041 and in particular based on terephthaldehyde and phloroglucinol.

[0139] The reinforcing elements 10-2, 10-3 and 10-2’, 10-3’ are described in Table 1 below.

[0140] [Table 1]

[0141] These tests confirm that, for core-glued reinforcing elements, the % by dry weight of textile reinforcing element is greater and as shown in Figure 3, we see that the adhesive composition penetrates to the core of the reinforcing element 10-1.

[0142] Shear measurement

[0143]The dynamic properties, in particular the tan(delta) max at 100°C, are measured on a viscoanalyzer (Metravib VA4000), according to standard ASTM D5992-96. The response of a sample of vulcanized composition (cylindrical test piece) is recorded. 2 mm thick and 79 mm2 in section), subjected to a sinusoidal stress in alternating simple shear, at a frequency of 10 Hz, under normal temperature conditions (100°C) according to standard ASTM D 1349-09. A deformation amplitude sweep is carried out from 0.1% to 50% (forward cycle), then from 50% to 0.1% (return cycle). On the return cycle, we record the value of the loss factor, noted tan(delta)max.

[0144] The hysteretic performance results (tan(ô)max at 23°C) are expressed in percentage base 100 compared to the CO control composite. A result greater than 100 indicates an improvement in hysteretic performance, i.e. a reduction in hysteresis.

[0145] Tensile tests

[0146] These tests make it possible to determine the elastic stresses and the breaking properties. Unless otherwise indicated, they are carried out in accordance with ASTM D412-98 of 1998 (specimen C). ASTM C specimens with a thickness of 2.5 mm are used. The force displacement curves are made at first elongation (i.e. without accommodation cycles), at a speed of 500 mm/min, at a temperature of 23°C ± 2°C and under normal humidity conditions (50 ± 5 % relative humidity) according to the ASTM D1349 standard of 1999. The secant modulus is measured at 20% elongation, denoted MSV20% and expressed in MPa. The true secant modulus (MSV) is the ratio between the extension stress compared to the real section of the specimen.

[0147] The mixture stiffness results (MSV) are expressed as a percentage base 100 relative to the control composite C0. A result greater than 100 indicates achieving an even higher mixture stiffness compared to the control. [0148]The different composites described below are brought together in Table 2 below as well as the corresponding results.

[0149] Witness C0 is a composition conventionally used in tire treads based on 100 phr of natural rubber, 52 phr of 300 series carbon black, 1 phr of anti-ozone wax (“Varazon 4959” from the company Sasol Wax), 1.5 PCE of antioxidant (N-1, 3-dimethylbutyl-N-phenyl-para-phenylenediamine “santoflex 6-PPD” from the company Flexsys), 1 pce of stearic acid (“pristene 4931 » from the company Uniquema), 1 PCE of 2, 2, 4-trimethyl 1-1,2- dihydroquinoline (“pilnox TMQ” from the company Nocil), 1.7 pce of soluble sulfur, 1.1 PCE of N-Cyclohexyl- 2-Benzothiazol-sulfenamide (“Santocure CBS” from the company Flexsys) and 2.5 pce of industrial grade ZnO (company Umicore), control C0 does not contain short fibers.

[0150]The composite C1 comprises the control composition C0 and a short unglued PA 6.6 fiber.

[0151] The composite E1 comprises the control composition C0 and short PA 6.6 fibers glued but not glued to the core.

[0152]The composite C2 comprises the control composition C0 and short fibers made of Unglued PET.

[0153]Composite E2 comprises the control composition CO and short PET fibers glued but not glued to the core.

[0154]The composite F1 according to the invention comprises the control composition CO and short PA 6.6 fibers glued to the core.

[0155]The composite F2 according to the invention comprises the control composition CO and short PET fibers glued to the core.

[0156] [Table 2]

[0157] These tests confirm that, for the composites F1 and F2 according to the invention, a very high mixture rigidity can be achieved without degrading the hysteresis performance. [0158] The invention is not limited to the embodiments described above.

Claims

CLAIMS Core-glued textile reinforcement element (10), characterized in that it comprises: at least one or more textile filaments and/or several natural or organic polymeric textile fibers; in which the glued textile reinforcing element (10) is obtained by a process comprising a step of manufacturing the glued textile reinforcing element (10) in which a textile reinforcing element is passed through a bath of composition adhesive, the quantity of dry material resulting from the bath of the adhesive composition representing 9.6 to 20% by dry weight of textile reinforcing element. Core-glued textile reinforcing element (10) according to the preceding claim, in which the organic polymeric filaments and fibers are chosen from polyester, aromatic polyamide or copolyamide, aliphatic polyamide and preferably from polyester filaments and fibers such as such as PET or polyamide such as nylons PA4.6, PA56, PA6, PA6.6 and PA6.10. Core-glued textile reinforcing element (10) according to claim 1, in which the natural filaments and fibers are chosen from natural cellulosic fibers, linen, hemp, cotton, sisal, kenaf, bamboo, jute, coconut. Core-glued textile reinforcing element (10) according to any one of the preceding claims, in which the weight of adhesive composition is greater than or equal to 70 g/kg of reinforcing element. Core-glued textile reinforcing element (10) according to any one of the preceding claims, in which the weight of adhesive composition is greater than or equal to 80g/kg of reinforcing element and preferably greater than or equal to 100 g/kg reinforcing element. Core-glued textile reinforcing element (10) according to any one of the preceding claims, in which the weight of adhesive composition is less than or equal to 250 g/kg of reinforcing element and preferably less than or equal to 200 g/kg kg of reinforcing element. Core-glued textile reinforcing element (10) according to any one of the preceding claims, in which the textile reinforcing element comprises a single multifilament strand. Core-glued textile reinforcing element (10) according to any one of the preceding claims, in which the adhesive composition is based on at least one phenol-aldehyde resin based on at least: an aldehyde; a polyphenol comprising one or more aromatic ring(s), it being understood that: in the case of a single aromatic ring, the latter carries two or three hydroxyl functions in the meta position relative to the other or relative to each other, the remainder of the aromatic ring being unsubstituted; in the case of several aromatic nuclei, at least two of them each carry two or three hydroxyl functions in the meta position relative to each other or to each other, it being understood that the two positions in ortho of at least one of these hydroxyl functions are unsubstituted. Core-glued textile reinforcing element (10) according to the preceding claim, in which the aldehyde is chosen from the group consisting of 1,2-benzene-dicarboxaldehyde, 1,3-benzene-dicarboxaldehyde, 1,4- benzene-dicarboxaldehyde, 2-hydroxybenzene-1,3,5-tricarbaldehyde and mixtures of these compounds and preferably 1,4-benzene-dicarboxaldehyde. Core-glued textile reinforcing element (10) according to claim 8 or 9, in which the polyphenol is phloroglucinol. Short fiber (E) obtained by cutting the core-glued textile reinforcing element (10) according to any one of the preceding claims, to a length comprised in a range ranging from 0.1 to 20 mm, and preferably from 0.4 to 10 mm. Short fiber (E) according to the preceding claim, having a diameter comprised in a range ranging from 0.5 to 100 pm and preferably from 1 to 30 pm. Reinforced elastomer composite (F) with at least one short fiber (E) according to any one of claims 11 or 12, comprising an elastomer matrix in which the short fiber (E) is embedded. Reinforced product comprising at least one composite (F) according to the preceding claim. Reinforced product according to the preceding claim chosen from conveyor belts, transmission belts, tracks, pneumatic or non-pneumatic wheel tires.