Textile reinforcement element bonded throughout, short fiber and product reinforced with at least one short fiber

Abstract

The invention relates to a core-bonded textile reinforcement element, which comprises: at least one or more textile filaments and / or several natural or organic polymeric textile fibers; The core-bonded textile reinforcement element is obtained by a process comprising a manufacturing step of the bonded textile reinforcement element in which a textile reinforcement element is passed through a bath of adhesive composition, the quantity of dry matter from the bath of adhesive composition represents 10 to 20% by dry weight of textile reinforcement element.

Description

Title of the invention: Core-bonded textile reinforcement element, short fiber, and product reinforced with at least one short fiber

[0001] The field of the present invention relates to core-bonded textile reinforcement elements, short fibers obtained from cutting core-bonded textile reinforcement 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 selected from conveyor belts, transmission belts, tracks, and tires for pneumatic or non-pneumatic wheels.

[0002] The prior art, in particular EPI792755, is known, of short fibers of Carbon fibers are coated with an aqueous RFL (Resorcinol-Formaldehyde-Latex) adhesive composition to reinforce an elastomeric matrix. The fiber coating must be such that it prevents any fiber agglutination during the adhesive treatment step, agglutination being defined as more than five individual chopped fibers sticking to each other along at least part of the longitudinal axis of the fiber. After adding the chopped fibers to the elastomer mixture in the mixer, the mixture must be sufficient to prevent any further fiber agglutination within the elastomer.

[0003] We also know from the prior art, in particular from EP 1349889, a process of core bonding of carbon fibers to reinforce an elastomeric matrix in which the fiber is twisted and then integrated as continuous reinforcement.

[0004] The disadvantage of carbon fibers is, on the one hand, that they are easily damaged during the textile process and, on the other hand, that they have low elongation at break. Finally, carbon fibers are relatively expensive, which limits their use in pneumatic applications.

[0005] However, it is desirable to find new core-bonded reinforcing elements with a sufficiently high elongation at break and industrially feasible to guarantee good adhesion of reinforcement / elastomeric matrix.

[0006] The invention aims to provide a core-bonded reinforcing element meeting this objective.

[0007] The invention relates to a core-bonded reinforcing element comprising: at least one or more textile filaments and / or several natural or organic polymeric textile fibers; in which the core-bonded textile reinforcement element is obtained by a process comprising a manufacturing step of the bonded textile reinforcement element in in which a textile reinforcement element is passed through a bath of adhesive composition, the quantity of dry material from the bath of adhesive composition representing 7 to 20% by dry weight of textile reinforcement element.

[0008] The Applicant notes that the through-bonded reinforcing element obtained by the through-bonding process described below has a quantity of dry matter from the adhesive bath representing 7 to 20% by dry weight of textile reinforcing element, which is significantly higher than that of a reinforcing element bonded using a conventional bonding process. The compounds mentioned in the description may be of fossil origin or bio-based. In the latter case, they may be partially or totally derived from biomass or obtained from renewable raw materials derived from biomass. Similarly, the compounds mentioned may also come from the recycling of previously used materials; that is, they may be partially or totally derived from a recycling process, or obtained from raw materials themselves derived from a recycling process.This includes filaments, fibers, polymers, plasticizers, fillers, etc.

[0009] A filament is a very long and continuous unit element generally obtained by spinning a molten material. It can be either artificial or synthetic.

[0010] Preferably, each filament and / or each fiber is selected from polyester filaments and fibers, polyamide filaments and fibers, polyketone filaments and fibers, polyurethane filaments and fibers, acrylic filaments and fibers, polyolefin filaments and fibers, polyetheretherketone filaments and fibers and assemblies of these filaments and fibers, preferably from polyester filaments and fibers, polyamide filaments and fibers and assemblies of these filaments and fibers, and more preferably organic synthetic filaments and fibers are polyester or polyamide filaments and fibers such as PA4.6, PA56, PA6, PA6.6 and PA6.10 nylons.

[0011] By definition, a textile reinforcement element is an assembly of these filaments and fibers. Each reinforcement element is impregnated with a composition ensuring the cohesion of these filaments and fibers with each other and preventing the fraying of each reinforcement element.

[0012] We will mention RFL (Resorcinol - Formaldehyde - Latex) type adhesive compositions but also adhesive compositions as described in WO2015118041.

[0013] Preferably, each reinforcing element can also be impregnated with an aqueous pre-adhesive, particularly for fibers and / or filaments with poor affinity for RFL-type adhesive compositions. This pre-adhesion step is carried out upstream of the element manufacturing step. of textile reinforcement bonded throughout. Examples include pre-adhesives containing epoxy compounds and isocyanate compounds.

[0014] The quantity of adhesive composition is measured by chemical attack, either by attack of the adhesive composition or by attack of the fiber.

[0015] For polyamides, the chemical attack is carried out by treating the fiber with a hot acidic 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 dividing the weight of the residue by the weight of the dry, unbonded fiber.

[0016] For other fibers such as polyester, polyketone, polyurethane, acrylic, polyolefin, or polyetheretherketone fibers, the chemical attack is carried out by attacking the adhesive composition with an acidic oxidizing solution. The adhesive composition, as well as the sizing and pre-adhesive, are destroyed.

[0017] The residue consisting of the fibers is recovered and weighed. The weight of the adhesive composition is determined by weighing the fibers before and after the adhesive composition has been applied, correcting the result obtained by the amount of sizing and pre-adhesive deposited on the fiber.

[0018] The quantity of sizing and pre-adhesion deposited on the fiber can be determined experimentally by attacking the raw fiber.

[0019] Polyester filament and / or fiber refers to a collection of filaments made up of linear macromolecules formed from 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 mention polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polypropylene terephthalate (PPT), and polypropylene naphthalate (PPN).

[0020] Aromatic polyamide filament and / or fiber, or aromatic copolyamide, is a well-known term referring to a set of filaments made up of linear macromolecules formed from aromatic groups linked together by amide bonds, at least 85% of which are directly linked to two aromatic rings, and more particularly to poly(p-phenylene terephthalamide) (or PPTA) fibers, which have long been manufactured from optically anisotropic spinning compositions. Examples of aromatic polyamides or aromatic copolyamides include polyarylamides (or PAA, notably known under the trade name Ixef from Solvay), poly(metaxylylene adipamide), polyphthalamides (or PPA, notably known under the trade name Amodel from Solvay), and amorphous semi-aromatic polyamides (or PA 6-3T, notably known under the trade name Trogamid of the company Evonik), meta-aramids (or poly(metaphenylene isophthalamide or PA MPD-I notably known under the trade name Nomex of the company Du Pont de Nemours) or para-aramids (or poly(paraphenylene terephthalamide or PA PPD-T notably known under the trade name Kevlar of the company Du Pont de Nemours or Twaron of the company Teijin).

[0021] By aliphatic polyamide filament and / or fiber, we mean a set of filaments made up of linear macromolecules of polymers or copolymers containing amide functional groups without aromatic rings and which can be synthesized by polycondensation between a carboxylic acid and an amine. Examples of aliphatic polyamides include PA4.6, PA6, PA6.6, and PA6.10 nylons, and in particular Zytel from DuPont, Technyl from Solvay, and Rilsamid from Arkema.

[0022] Advantageously, the count 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.

[0023] The density (or linear mass) of each filament and / or fiber is determined according to ASTM D1423. The density is given in tex (mass in grams of 1000 m of product - reminder: 0.111 tex equals 1 denier). The density of reinforcing elements in the composite is the number of reinforcing elements per decimeter of the composite in the direction perpendicular to the direction in which the reinforcing elements extend parallel to each other.

[0024] In one embodiment, advantageously, the organic polymer 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 filaments and fibers such as PA4.6, PA56, PA6, PA6.6 and PA6.10 nylons.

[0025] In another embodiment, advantageously, the natural filaments and fibers are chosen from natural cellulosic fibers, flax, hemp, cotton, sisal, kenaf, bamboo, jute, coconut.

[0026] Advantageously, the weight of adhesive composition is greater than or equal to 70 g / kg of reinforcing element.

[0027] Preferably, the weight of adhesive composition is greater than or equal to 80g / kg of reinforcing element and preferably greater than or equal to 100g / kg of reinforcing element.

[0028] 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.

[0029] 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.

[0030] Advantageously, the weight of the 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. Indeed, an excessive layer of adhesive composition reduces the properties of the fiber mixtures and is often an indication of an excess of adhesive composition on the surface.

[0031] In one embodiment, the textile reinforcement element comprises a single multi-stranded strand.

[0032] Preferably, in this embodiment, the textile reinforcement element consists of a single multifilamentary strand.

[0033] In another embodiment, each textile reinforcement element comprises several multifilamentary strands.

[0034] 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 meta position relative to each other, the rest of the aromatic ring being unsubstituted; in the case of several aromatic rings, at least two of them each carry two or three hydroxyl functions in meta positions relative to each other or to each other, it being understood that the two ortho positions of at least one of these hydroxyl functions are unsubstituted.

[0035] By "meta position relative to each other", it will be understood 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.

[0036] By "in ortho position of a function", we will mean the position occupied by the carbon of the aromatic nucleus immediately adjacent to the carbon of the aromatic nucleus bearing the function.

[0037] By "link" of a nucleus, we mean an atom constituting the nucleus's skeleton. Thus, for example, a benzene ring comprises six links, each link consisting of a carbon atom. In another example, a furanine ring comprises five links, four of which are each consisting of a carbon atom and the remaining link consisting of an oxygen atom.

[0038] “CHO” represents the aldehyde function.

[0039] “CH2OH” represents the hydroxymethyl function.

[0040] By "aromatic polyphenol" is meant an aromatic compound comprising at least one benzene ring bearing more than one hydroxyl function.

[0041] By “resin based on”, it should be understood that the resin comprises the mixture and / or reaction product of the various basic constituents used for this resin as defined above and that this resin is solely based on the basic constituents of the composition.

[0042] 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 under industrial conditions and at a reduced cost.

[0043] Aldehyde compound

[0044] An essential constituent of the adhesive composition is a compound comprising at least one aldehyde.

[0045] According to the invention, the adhesive composition is based on at least one (i.e. one or more) aldehyde.

[0046] In one embodiment, the aldehyde is formaldehyde.

[0047] In another embodiment, the aldehyde is a carrier aromatic aldehyde of at least one aldehyde function.

[0048] Advantageously in this embodiment, the aromatic aldehyde carries at least two aldehyde functions.

[0049] Preferably, the aromatic ring of the aromatic aldehyde is a benzene ring.

[0050] 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.

[0051] Polyphenol compound

[0052] 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 ring bearing at least two hydroxyl groups in meta positions relative to each other, the two ortho positions of at least one of the hydroxyl groups being unsubstituted.

[0053] According to the invention, the aromatic polyphenol can be, in one embodiment, a simple aromatic polyphenol molecule comprising one or more aromatic rings, at least one of these aromatic rings, or even each aromatic ring, bearing at least two hydroxyl functions in meta positions relative to each other, the two ortho positions of at least one of the hydroxyl functions being unsubstituted.

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062] In a preferred embodiment, the aromatic core of the aromatic polyphenol bears three hydroxyl functions in meta positions relative to each other. Preferably, the two ortho positions of each hydroxyl function are unsubstituted. This means that the two carbon atoms located on either side (in ortho position) of the hydroxylated carbon atom (i.e., bearing the hydroxyl function) each have a single hydrogen atom attached. Even more preferentially, the remainder of the aromatic ring of the aromatic polyphenol is unsubstituted. This means that the other carbon atoms of the remainder of the aromatic ring (those other than the carbon atoms bearing the hydroxyl groups) are bonded to a single hydrogen atom. In one embodiment, the aromatic polyphenol comprises several aromatic rings, at least two of them each bearing at least two hydroxyl functions in meta positions relative to each other, the two ortho positions of at least one of the hydroxyl functions of at least one aromatic ring being unsubstituted. In a preferred embodiment, at least one of the aromatic rings of the aromatic polyphenol bears three hydroxyl functions in meta positions relative to each other. Preferably, the two ortho positions of each hydroxyl function of at least one aromatic ring are unsubstituted. Even more preferentially, the two ortho positions of each hydroxyl function of each aromatic ring are unsubstituted. Advantageously, the aromatic ring or rings of the aromatic polyphenol are benzene rings. As an example of an aromatic polyphenol containing a single aromatic ring, we can cite in particular resorcinol and phloroglucinol, for a reminder of their respective developed formulas (IV) and (V): (IV) (V)

[0063] For example, in the case where the aromatic polyphenol has several aromatic rings, at least two of these aromatic rings, identical or different ones are chosen from those of general formulas:

[0064] in which the symbols Zl, Z2, identical or different if there are several on the same aromatic nucleus, represent an atom (for example carbon, sulfur or oxygen) or a bonding group by definition at least divalent, which links at least these two aromatic nuclei to the rest of the aromatic polyphenol. Another example of an aromatic polyphenol is 2,2',4,4'-tetrahydroxydiphenyl sulfide with the following structural formula (VII):

[0065] OH (VII) Another example of an aromatic polyphenol is 2,2',4,4'-tetrahydroxydiphenyl benzophenone with the following structural formula (VIII):

[0066]

[0067] It is noted that each compound VII and VIII is an aromatic polyphenol comprising two aromatic rings (of formula VI-c) each of which carries at least two (in this case two) hydroxyl functions in meta position relative to each other. It is noted that in the case of an aromatic polyphenol with at least one aromatic ring conforming to the formula Vl-b, the two ortho positions of each hydroxyl group of at least one aromatic ring are unsubstituted. In the case of a po- aromatic lyphenol comprising several aromatic rings conforming to the formula Vl-b, the two ortho positions of each hydroxyl function of each aromatic ring are unsubstituted.

[0068] According to one embodiment of the invention, the aromatic polyphenol is selected 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.

[0069] In one embodiment, the aromatic polyphenol A2 comprises a precondensed resin based on the aromatic polyphenol as described in any one of these embodiments.

[0070] This pre-condensed resin is advantageously based on: • of 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 mixtures thereof; and • of 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 ring bearing at least one aldehyde function.

[0071] The compound capable of reacting with the aromatic polyphenol may be an Al compound as defined above or any other aldehyde. Advantageously, said compound is chosen from the group consisting of an aromatic compound comprising an aromatic ring bearing at least two functions, one of these functions being a hydroxymethyl function, the other being an aldehyde function or a hydroxymethyl function, formaldehyde, furfuraldehyde, 2,5-furanedicarboxaldehyde, 1,4-benzenedicarboxaldehyde, 1,3-benzenedicarboxaldehyde, 1,2-benzenedicarboxaldehyde and mixtures of these compounds.Most advantageously, when the compound capable of reacting with the aromatic polyphenol is an aromatic compound comprising an aromatic ring bearing at least two functions, one of these functions being a hydroxymethyl function, the other being an aldehyde function or a hydroxymethyl function, this compound is chosen from the group consisting of 5-(hydroxymethyl)-furfural, 2,5-di(hydroxymethyl)furan and mixtures of these compounds.

[0072] Thus, in the pre-condensed aromatic polyphenol-based resin, the repeating motif meets the characteristics of the aromatic polyphenol defined previously except that at least one of the carbon atoms of the aromatic ring, which was unsubstituted, is bonded to another motif.

[0073] Regardless of the compound other than the aromatic polyphenol used as the basis for the pre-condensed resin, this pre-condensed resin is free of free formaldehyde. Indeed, even if 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 free of free formaldehyde that could react with a compound Al according to the invention in a subsequent step.

[0074] Aromatic polyphenol A2 may also comprise a mixture of a free aromatic polyphenol molecule and a pre-condensed aromatic polyphenol resin, as described above. In particular, aromatic polyphenol A2 may also comprise a mixture of phloroglucinol and a pre-condensed phloroglucinol resin.

[0075] Method for manufacturing the core-bonded reinforcing element according to the invention

[0076] We will now describe an example of a process for bonding a reinforcing element through to the core.

[0077] During this process, the reinforcing element is a PA 6.6 textile reinforcing element which is bonded throughout by an aqueous adhesive composition based on RFL.

[0078] An optional step is carried out to vacuum the reinforcing element so as to open the filaments and / or fibers constituting it, then a step is carried out to bring the textile reinforcing element into contact in a tray with an adhesive composition, the tray being equipped with two central slots machined in the shape of a dome so as to open the reinforcing element, then in another step the reinforcing element is passed through at least two other trays, each tray containing an identical adhesive composition, each tray being equipped downstream with a roller of the type "rabbit's foot" over which the reinforcing element is passed 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.

[0079] Short fiber according to the invention

[0080] The invention also relates to a short fiber obtained by cutting the core-bonded textile reinforcement element as described above, to a length in a range from 0.1 to 20 mm, and preferably from 0.4 to 10 mm.

[0081] By short fiber, we mean a discontinuous fiber of reduced length. It can be either natural fibers or cut filaments.

[0082] Advantageously, the diameter is within a range of 0.5 to 100 pm and preferably from 1 to 30 pm.

[0083] Method for manufacturing the short fiber according to the invention

[0084] The short fiber is obtained by cutting the core-bonded textile reinforcement element as described above.

[0085] COMPOSITE ACCORDING TO THE INVENTION

[0086] 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.

[0087] The elastomer matrix is ​​based on an elastomer composition comprising at least one elastomer and another constituent.

[0088] Preferably, the elastomer composition comprises a diene elastomer. By elastomer or rubber (the two terms being synonymous) of the "diene" type, one generally means an elastomer derived at least in part (i.e. a homopolymer or a copolymer) from diene monomers (monomers bearing two carbon-carbon double bonds, conjugated or not).

[0089] 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 association with any type of synthetic elastomer other than diene, or even with polymers other than elastomers, for example thermoplastic polymers.

[0090] In a first embodiment preferably intended for pneumatic use, the elastomer composition comprises a diene elastomer selected from the group consisting of polybutadienes (BR), ethylene butadiene rubber (EBR), natural rubber (NR), synthetic polyisoprenes (IR), various butadiene copolymers, various isoprene copolymers, and mixtures of these elastomers.

[0091] Such copolymers are more preferentially chosen from the group consisting of butadiene-styrene copolymers (SBR), whether the latter are prepared by emulsion polymerization (ESBR) or in solution (SSBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR) and isoprene-butadiene-styrene copolymers (SBIR).

[0092] In a second embodiment preferably intended for use as a belt, the elastomer composition comprises an elastomer selected from the group consisting of TPU (thermoplastic urethane), PU (polyurethane), an ethylene alpha olefin type elastomer, a polychloroprene elastomer and mixtures of these elastomers, and one or more other elastomers. The elastomer composition may also comprise one or more other components.

[0093] Advantageously, the ethylene alpha olefin type elastomer is chosen in the group consisting of ethylene-propylene copolymers (EPM), copolymers ethylene-propylene-diene (EPDM) and mixtures of these copolymers.

[0094] Preferably, the elastomer composition includes a reinforcing filler.

[0095] When a reinforcing filler is used, any type of reinforcing filler known for its ability to reinforce an elastomer composition usable for the manufacture of tires can be used, for example an organic filler such as carbon black, an inorganic reinforcing filler such as silica, or a blend of these two types of filler, in particular a blend of carbon black and silica.

[0096] All carbon blacks conventionally used in tires (so-called tire-grade blacks) are suitable as carbon blacks. For example, reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades) are particularly suitable.

[0097] 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).

[0098] Examples of organic fillers other than carbon blacks include functionalized polyvinylaromatic organic fillers as described in applications WO-A-2006 / 069792 and WO-A-2006 / 069793.

[0099] In this application, the term "reinforcing inorganic filler" is defined as any inorganic or mineral filler (regardless of its color and origin (natural or synthetic), also called "white" filler, "light" filler, or even "non-black filler" ("non-black filler") as opposed to carbon black, capable of reinforcing an elastomeric composition on its own, without any means other than an intermediate coupling agent; in other words, capable of replacing conventional pneumatic-grade carbon black in its reinforcing function. Such a filler is generally characterized, in a known manner, by the presence of hydroxyl groups (-OH) on its surface.

[0100] The physical state in which the reinforcing inorganic filler is presented is irrelevant, whether it is in the form of powder, micro-beads, granules, spheres, or any other suitable densified form. Of course, the term "reinforcing inorganic filler" also includes mixtures of different reinforcing inorganic fillers, in particular highly dispersible siliceous and / or aluminous fillers as described below.

[0101] Suitable inorganic reinforcing fillers include mineral fillers of the siliceous type, in particular silica (SiO2), or of the aluminous type, in particular alumina (Al2O3). The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenated silica exhibiting a BET surface area and a CTAB specific surface area both less than 450 m2 / g, preferably from 30 to 400 m2 / g. As examples of highly dispersible precipitated silicas (known as "HDS"), we will mention for example the "Ultrasil" 7000 and "Ultrasil" 7005 silicas from the company Evonik, the "Zeosil" 1165MP, 1135MP and 1115MP silicas from the company Rhodia, the "Hi-Sil" EZ150G silica from the company PPG, the "Zeopol" 8715, 8745 and 8755 silicas from the company Huber, the silicas with high specific surface area as described in application WO 03 / 16837.

[0102] Finally, a person skilled in the art will understand that, as an equivalent charge to the reinforcing inorganic charge described in this paragraph, a reinforcing charge of another nature, in particular organic, could be used, provided that this reinforcing charge is covered with an inorganic layer such as silica, or has functional sites on its surface, in particular hydroxyl sites, requiring the use of a coupling agent to establish the bond between the charge and the elastomer.

[0103] Preferably, the total reinforcing charge ratio (carbon black and / or inorganic reinforcing charge such as silica) is in the range of 5 to 120 pc, more preferably 5 to 100 pc and even more preferably 5 to 90 pc.

[0104] Carbon black can advantageously constitute the sole reinforcing filler or the major reinforcing filler. Of course, a single carbon black or a blend of several carbon blacks of different ASTM grades can be used. Carbon black can also be used in blends with other reinforcing fillers, and in particular inorganic reinforcing fillers such as those described above, and especially silica.

[0105] When an inorganic filler (for example silica) is used in the rubber composition, alone or in blending with carbon black, its proportion is in the range of 0 to 100 pc, preferably from 0 to 70 pc, particularly also from 5 to 70 pc, and even more preferably this proportion varies from 5 to 50 pc, particularly from 5 to 40 pc.

[0106] Preferably, the elastomer composition includes various additives.

[0107] Rubber compositions may also include all or part of the usual additives commonly used in elastomer compositions for the manufacture of tires, such as plasticizers or extending oils, whether aromatic or non-aromatic, pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents or adhesion promoters.

[0108] Preferably, the elastomer composition comprises a crosslinking system.

[0109] In the first embodiment preferably intended for pneumatic, tracked, or conveyor belt use, the elastomer composition comprises a vulcanization system.

[0110] The vulcanization system includes a sulfur-donating agent, for example sulfur.

[0111] Preferably, the vulcanization system includes vulcanization activators such as zinc oxide and stearic acid.

[0112] Preferably, the vulcanization system includes a vulcanization accelerator and / or a vulcanization retarder.

[0113] Advantageously, the composite is such that the elastomer matrix is ​​based on an elastomer composition comprising a crosslinking system comprising a molecular sulfur content ranging from 1 to 5 pce.

[0114] Most advantageously, the molecular sulfur content of the crosslinking system of the elastomer composition is greater than or equal to 1.5 pc.

[0115] The sulfur content is measured by elemental analysis, using the Thermo Scientific Flash 2000 micro-analyzer. The analysis includes a step of combustion of the sample followed by a step of separation of the compounds formed.

[0116] Approximately 1 mg of sample is introduced into the microanalyzer, where it undergoes flash combustion at 1000°C under oxygen. The gases formed are then oxidized by excess oxygen and a tungstic anhydride catalyst. A reduction step by passing the sample over copper then traps excess oxygen and reduces nitrogen oxides to N2 and sulfites to sulfur dioxide (SO2). Water is trapped, and the resulting N2, CO2, and SO2 compounds are separated on a chromatographic column and then detected by a heat-sensing chromatograph. Total sulfur is quantified by measuring the area of ​​the SO2 peak after calibration with standards.

[0117] The entire set of vulcanization accelerators, retarders, and activators is used at a preferential rate within a range of 0.5 to 15 parts per liter. The vulcanization activator(s) is / are used at a preferential rate within a range of 0.5 to 12 parts per liter.

[0118] The crosslinking system itself is preferably based on sulfur and a primary vulcanization accelerator, in particular a sul-fenamide type accelerator. Various known secondary accelerators or vulcanization activators, such as zinc oxide, stearic acid, guanidine derivatives (in particular diphenylguanidine), etc., are added to this vulcanization system.

[0119] Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur may be used as an accelerator (primary or secondary), in particular thiazole-type accelerators and their derivatives, thiuram-type accelerators, and zinc dithiocarbamate-type accelerators. These accelerators are most preferably chosen from the group consisting of 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cy- clohexyl-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 sulfenamide (abbreviated "TBSI"), zinc dibenzyldithiocarbamate (abbreviated "ZBEC"), and mixtures of these compounds. Preferably, a sulfenamide-type primary accelerator is used.

[0120] In the second embodiment, preferably intended for belt use, the crosslinking system is substantially sulfur-free and advantageously comprises a peroxide, preferably an organic peroxide. Advantageously, the peroxide content ranges from 0.5 to 8 parts per liter. Advantageously, the crosslinking system comprises a co-crosslinking agent, preferably sulfur or triallyl cyanurate. Advantageously, the co-crosslinking agent content ranges from 0.5 to 5 parts per liter.

[0121] PRODUCT REINFORCED ACCORDING TO THE INVENTION

[0122] 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, and tires for pneumatic or non-pneumatic wheels.

[0123] The invention will be better understood upon reading the following description, given solely by way of non-limiting example and made with reference to the drawings in which: - [Fig.1] is a diagram of a composite F according to the invention; - [Fig. 2] is a scanning electron microscope view of the Fl composite according to the invention; and - [Fig.3] is an enlargement of a cross-sectional view of a core-bonded reinforcement element 10-1 according to the invention.

[0124] EXAMPLE OF A COMPOSITE ACCORDING TO THE INVENTION

[0125] 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.

[0126] In [Fig. 1], the polymer matrix M and the short fibers E are shown in an X, Y, Z coordinate system in which the Y direction is the radial direction and the X and Z directions are the axial and circumferential directions. In [Fig. 1], the composite F comprises several short fibers E arranged randomly within the composite and collectively embedded in the polymer matrix M. Here, the polymeric matrix M is an elastomeric matrix based on an elastomeric composition.

[0127] On [Fig.2], a scanning electron microscope sectional enlargement of a composite Fl according to the invention as described in Table 2 below is observed, with the white areas of the core bonding of the short fiber E.

[0128] EXAMPLE OF A REINFORCING ELEMENT BOND ALL THROUGHOUT THE INVENTION

[0129] Figure 3 is an enlargement of a cross-sectional view of a bonded reinforcing element. at core 10-1 according to the invention.

[0130] This reinforcement element 10-1 will be described in Table 1 below.

[0131] Of course, the invention relates to the objects previously described, namely the reinforced product such as the conveyor belt, the transmission belt, the track, the tire for pneumatic or non-pneumatic wheel comprising it, both in the raw state (before cross-linking) and in the cured state (after cross-linking).

[0132] COMPARATIVE TESTS

[0133] The various reinforcement elements described below are gathered in Table 1 below, along with the corresponding results of % by dry weight of adhesive composition.

[0134] The witness is a PA 6.6 reinforcing element bonded by a well-known process of dipping the PA 6.6 fiber in a bath of an aqueous adhesive composition based on RFL, adhesives 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.

[0135] The reinforcing element 10-1 is a PA 6.6 140 tex reinforcing element bonded by a core bonding process as described above in a bath of an aqueous adhesive composition based on RFL.

[0136] The reinforcing element 10-1' is a PA 6.6 140 tex reinforcing element bonded by a core bonding process as described above in a bath of an aqueous adhesive composition based on PT, the PT adhesive being chosen from the adhesive compositions as described in WO2015118041 and in particular based on terephtaldehyde and phloroglucinol.

[0137] The reinforcement elements 10-2, 10-3 and 10-2', 10-3' are described in Table 1 below.

[0138] [Tables 1] Reinforcement Element Witness 10-1 10-1' 10-2 10-2' 10-3 10-3' Fiber Type PA 6.6 PA 6.6 PA 6.6 PA 6.6 PA 6.6 PA 6.6 PA 6.6 Title (Tex) 140 140 140 47 47 376 376 Bonding / Adhesive Type RFL RFL PT RFL PT RFL PT Core Bonding no yes yes yes yes yes yes yes Adhesive Weight (g / kg) 50 148 127 113 109 96 104 % by dry weight of textile reinforcement element 5 14.8 12.7 11.3 10.9 9.6 10.4

[0139] These tests confirm that, for the core-bonded reinforcing elements, the % by dry weight of textile reinforcing element is greater and, as shown in [Fig.3], the adhesive composition penetrates to the core of the reinforcing element 10-1.

[0140] Shear measurement

[0141] The dynamic properties, in particular the maximum tan(delta) at 100°C, are measured on a viscoelastic analyzer (Metravib VA4000), according to ASTM D5992-96. The response of a vulcanized composition sample (cylindrical specimen 2 mm thick and 79 mm² cross-section) is recorded under sinusoidal loading in alternating simple shear at a frequency of 10 Hz, under standard temperature conditions (100°C) according to ASTM D 1349-09. A strain amplitude sweep is performed from 0.1% to 50% (forward cycle), then from 50% to 0.1% (return cycle). During the return cycle, the value of the loss factor, denoted tan(delta)max, is recorded.

[0142] The hysteretic performance results (tan(ô)max at 23°C) are expressed as a percentage based on 100 relative to the control composite C0. A result greater than 100 indicates an improvement in hysteretic performance, i.e. a reduction in hysteresis.

[0143] Tensile tests

[0144] These tests determine the yield strength and breaking properties. Unless otherwise specified, they are performed in accordance with ASTM standards. D412-98 of 1998 (C specimen). ASTM C specimens with a thickness of 2.5 mm are used. Force-displacement curves are performed 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 ASTM D1349 of 1999. The secant modulus at 20% elongation, denoted MSV20% and expressed in MPa, is measured. The true secant modulus (MSV) is the ratio of the tensile stress to the actual cross-sectional area of ​​the specimen.

[0145] The mixture stiffness results (MSV) are expressed as a percentage based on 100 relative to the control composite C0. A result greater than 100 indicates achieving an even higher mixture stiffness compared to the control.

[0146] The various composites described below are gathered in Table 2 below, along with the corresponding results.

[0147] Witness C0 is a composition conventionally used in tire treads based on 100 parts per cent of natural rubber, 52 parts per cent of 300 series carbon black, 1 part per cent of ozone-suppressing wax (“Varazon 4959” from Sasol Wax), 1.5 parts per cent of antioxidant (Nl,3-dimethylbutyl-N-phenyl-para-phenylenediamine “santoflex 6-PPD” from Flexsys), 1 part per cent of stearic acid (“pristene 4931” from Uniquema), 1 part per cent of 2,2,4-trimethyl-1,2-dihydroquinoline (“pilnox TMQ” from Nocil), 1.7 parts per cent of soluble sulfur, 1.1 parts per cent of N-Cyclohexyl-2-Benzothiazol-sulfenamide (“Santocure CBS” from the Flexsys) and 2.5 pieces of industrial grade ZnO (Umicore company), the C0 control does not contain short fibers.

[0148] The Cl composite comprises the control composition C0 and a short unbonded PA 6.6 fiber.

[0149] The El composite comprises the control composition C0 and short PA 6.6 fibers bonded but not bonded throughout.

[0150] The C2 composite comprises the control composition C0 and unbonded short PET fibers.

[0151] The E2 composite comprises the control composition C0 and short PET fibers bonded but not bonded throughout.

[0152] The Fl composite according to the invention comprises the control composition C0 and short PA 6.6 fibers bonded throughout.

[0153] The F2 composite according to the invention comprises the control composition C0 and core-bonded short PET fibers.

[0154] [Tables2] Composite CO Cl C2 El E2 Fl F2 Fiber type - PA 6.6 PET PA 6.6 PET PA 6.6 PET Tenderness (Tex) - 140 110 140 55 140 110 Bonding no no no yes yes yes yes Core bonding no no no no no yes yes tan(φ)max at 23°C 100 114 125 106 116 106 111 MSV 100 1050 1067 1267 1150 1333 1767

[0155] These tests confirm that, for the Fl and F2 composites according to the invention, a very high mixture stiffness can be achieved without degrading the hysteresis performance.

[0156] The invention is not limited to the embodiments described above.

Claims

Claims

1. Core-bonded textile reinforcing element (10), characterized in that it comprises: at least one or more textile filaments and / or several natural or organic polymeric textile fibers; wherein the core-bonded textile reinforcing element (10) is obtained by a method comprising a step of manufacturing the bonded textile reinforcing element (10) in which a textile reinforcing element is passed through a bath of adhesive composition, the quantity of dry matter from the bath of the adhesive composition representing from 9.6 to 20% by dry weight of textile reinforcing element.

2. Core-bonded 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 PET or polyamide such as nylons PA4.6, PA56, PA6, PA6.6 and PA6.

10.

3. Core-bonded 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.

4. Core-bonded 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.

5. Core-bonded 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 100g / kg of reinforcing element.

6. Core-bonded 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 of reinforcing element.

7. A core-bonded textile reinforcing element (10) according to any preceding claim, wherein the textile reinforcing element comprises a single multifilament strand.

8. A core-bonded textile reinforcing element (10) according to any preceding claim, wherein the adhesive composition is based on at least one phenol-aldehyde resin based on at least: - one aldehyde; - one polyphenol comprising one or more aromatic nuclei, it being understood that: in the case of a single aromatic nucleus, the latter carries two or three hydroxyl functions in the meta position relative to each other or to each other, the remainder of the aromatic nucleus 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 ortho positions of at least one of these hydroxyl functions are unsubstituted.

9. Core-bonded 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.

10. A core-bonded textile reinforcing element (10) according to claim 8 or 9, wherein the polyphenol is phloroglucinol.

11. Short fiber (E) obtained by cutting the core-bonded textile reinforcing element (10) according to any one of the preceding claims, to a length within a range from 0.1 to 20 mm, and preferably from 0.4 to 10 mm.

12. Short fiber (E) according to the preceding claim, having a diameter in a range from 0.5 to 100 pm and preferably from 1 to 30 pm.

13. Reinforced elastomer composite (F) of 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.

14. Reinforced product comprising at least one composite (F) according to the preceding claim.

15. Reinforced product according to the preceding claim chosen from conveyor belts, transmission belts, tracks, pneumatic or non-pneumatic wheel tires.

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