RUBBER ITEM COMPOSITE

Abstract

The invention relates to a composite comprising at least one reinforcing element embedded in a rubber composition, the rubber composition being based on at least one isoprene elastomer, at most 50 parts per cent of an ethylene copolymer and a 1,3-diene, the ethylene units in the copolymer representing more than 50% by mole of the monomer units of the copolymer, at least 30 parts per cent of a reinforcing inorganic filler, and a crosslinking system.

Description

Title of the invention: RUBBER ARTICLE COMPOSITE Technical field of the invention

[0001] The present invention relates to the field of reinforced rubber compositions, and more particularly to plies comprising metallic or textile reinforcements embedded in a rubber composition, these plies being intended for use in particular in vehicle tires, conveyor belts or belts. Previous art

[0002] The performance of a vehicle tire, whether pneumatic (i.e., capable of supporting the vehicle's load by means of a pressurized gas) or non-pneumatic (i.e., capable of supporting the vehicle's load without the means of a pressurized gas, for example by means of stays, a conveyor belt, or a belt), is partly related to the rigidity of some of its components. Indeed, resistance to deformation is an important characteristic enabling it to withstand the stresses to which these objects are subjected.

[0003] This need for rigidity is particularly essential in the calendered plies of the top plies or in the lower zones, which are the areas near the rim, of a vehicle tire. In addition to rigidity, the compounds concerned must meet a broader set of specifications including low hysteresis, adhesion with the reinforcement, and the lowest possible evolution both in the raw state (i.e., before cross-linking of the rubber composition) and in the cured state (after cross-linking).

[0004] The required levels of rigidity can be obtained by two main levers: • Increasing the rate of reinforcing filler (black or silica), • The use of thermosetting resins which form a secondary network interpenetrated with the filler-elastomer-vulcanization network.

[0005] However, increasing the reinforcing filler content can lead to increased hysteresis and degraded processability of the raw mixtures, particularly due to increased raw stiffness and the possible occurrence of decohesion. Furthermore, the use of thermosetting resins can be an additional source of heat dissipation that may negatively impact hysteresis performance. In addition, some resin-hardener systems used in pneumatics are known to release formaldehyde and must therefore be handled with special precautions.

[0006] Other avenues have been explored to increase the rigidity of the compositions. By For example, document WO2014 / 114607 teaches the use of a highly saturated diene elastomer to increase the stiffness of rubber compositions without degrading their hysteresis properties. Since these compositions are primarily intended for use in tire treads, this document does not address adhesion or crack resistance issues. However, the presence of reinforcing elements, and therefore interfaces between elements with very different mechanical stiffness and behaviors (the reinforcing element and the rubber composition), can cause phenomena that are difficult to predict, particularly with regard to crack propagation, energy dissipation, and adhesion properties.

[0007] Document WO2020 / 074806 teaches the use of a natural rubber blend and a copolymer of ethylene and a 1,3-diene with carbon black to obtain good cohesion and ozone resistance properties, which are sought when used in the sidewalls of vehicle tires.

[0008] Continuing its research, the applicant discovered that a composite comprising at least one reinforcing element embedded in a rubber composition, the rubber composition being based on at least one isoprene elastomer, at most 50 parts of a copolymer of ethylene and a 1,3-diene, the ethylene units in the copolymer representing more than 50% by mole of the monomer units of the copolymer, at least 30 parts of an inorganic reinforcing filler, and a crosslinking system allowed a very good expression of the stiffness / hysteresis compromise without penalizing the other performances expected for a composition used in a sheet, in particular adhesion and resistance to cracking. Detailed description of the invention

[0009] The invention relates to a composite comprising at least one reinforcing element embedded in a rubber composition, the rubber composition being based on at least one isoprene elastomer, at most 50 parts of a copolymer of ethylene and a 1,3-diene, the ethylene units in the copolymer representing more than 50% by mole of the monomer units of the copolymer, at least 30 parts of a reinforcing inorganic filler, and a crosslinking system.

[0010] Preferably, the rubber composition comprises a metal oxide and a stearic acid derivative, the ratio of the metal oxide and stearic acid derivative, by weight, being greater than 2.

[0011] Preferably, the rubber composition comprises less than 10 parts, preferably less than 5 parts, of plasticizer.

[0012] Preferably, the copolymer of ethylene and a 1,3-diene comprises at least 60 mol% of ethylene units, preferably at least 65 mol% of units ethylene, more preferably at least 70 molar percent of ethylene units.

[0013] Preferably, the 1,3-diene units of the ethylene copolymer and a 1,3-diene are those of a 1,3-diene having 4 to 12 carbon atoms, preferably those of 1,3-butadiene, isoprene, 1,3-pentadiene, an aryl-1,3-butadiene and a mixture of these units.

[0014] Preferably, the reinforcing inorganic filler of the rubber composition is silica.

[0015] Preferably, the rubber composition comprises 30 to 150 parts per annum of silica.

[0016] Preferably, the rubber composition does not include carbon black, or includes less than 10 parts per annum, preferably less than 5 parts per annum.

[0017] Preferably, the reinforcing element comprises a textile or metallic wire element.

[0018] Preferably, the metallic wire element is a metallic elementary monofilament or an assembly of several metallic elementary monofilaments.

[0019] Preferably, the reinforcing element comprises a textile yarn element made of a thermoplastic or non-thermoplastic polymeric material.

[0020] The invention also relates to a vehicle tire comprising a composite according to the invention. Definitions

[0021] The carbon-containing 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. This includes, in particular, polymers, plasticizers, fillers, etc.

[0022] Any range of values ​​designated by the expression "between a and b" represents the range of values ​​greater than "a" and less than "b" (i.e., excluding bounds a and b), while any range of values ​​designated by the expression "from a to b" means the range of values ​​from "a" to "b" (i.e., including the strict bounds a and b). The abbreviation "pce" means parts by weight per hundred parts of elastomer (of the total elastomers if several elastomers are present).

[0023] In this description, the term "composition based on" means a composition comprising the mixture and / or the in situ reaction product of the various constituents used, some of these basic constituents (for example, the elastomer, the filler, or the constituents of the vulcanization system or other additive conventionally used in a rubber composition intended for the manufacture of tires) being capable of, or intended to react with each other, at least in part, during the various manufacturing phases of the composition intended for the manufacture of Vehicle tires.

[0024] In this application, "all the monomer units of the elastomer" or "all the monomer units of the elastomer" means all the repeating units constituting the elastomer that result from the insertion of the monomers into the elastomer chain by polymerization. Unless otherwise specified, the contents of a monomer unit or repeating unit in the highly saturated diene elastomer are given as a molar percentage calculated on the basis of all the monomer units of the elastomer. Copolymer of ethylene and a 1,3-diene

[0025] The rubber composition of the composite according to the invention comprises at most 50 parts of a copolymer of ethylene and a 1,3-diene, the ethylene units in the copolymer representing more than 50% by mole of the monomer units of the copolymer.

[0026] The copolymer of ethylene and a 1,3-diene is a highly saturated diene elastomer, preferably statistically saturated, which comprises ethylene units resulting from the polymerization of ethylene. The term "ethylene unit" is known to refer to the -(CH2-CH2)- motif resulting from the insertion of ethylene into the elastomer chain. The copolymer of ethylene and a 1,3-diene is rich in ethylene units, since the ethylene units represent more than 50% by mole of all the monomer units of the elastomer.

[0027] Preferably, the ethylene-1,3-diene copolymer comprises at least 60 mol% of ethylene units, preferably at least 65 mol% of ethylene units, and more preferably at least 70 mol% of ethylene units. In other words, the ethylene units in the ethylene-1,3-diene copolymer preferably represent at least 60 mol% of all the monomer units of the ethylene-1,3-diene copolymer, and more preferably at least 65 mol% of all the monomer units of the ethylene-1,3-diene copolymer. Even more preferably, the ethylene units represent at least 70 mol% of all the monomer units of the ethylene-1,3-diene copolymer.

[0028] Preferably, the ethylene units in the ethylene-1,3-diene copolymer represent at most 90% by mole of all the monomer units in the ethylene-1,3-diene copolymer. More preferably, the ethylene units represent at most 85% by mole of all the monomer units in the ethylene-1,3-diene copolymer. Even more preferably, the ethylene units represent at most 80% by mole of all the monomer units in the ethylene-1,3-diene copolymer.

[0029] According to an advantageous embodiment, the copolymer of ethylene and a 1,3-diene comprises 60% to 90% mol of ethylene units, particularly 60% to 85% mol of ethylene units, the mol percentage being calculated on the basis of all the monomer units of the ethylene-1,3-diene copolymer. More advantageously, the ethylene-1,3-diene copolymer comprises 60% to 80% molar ethylene units, molar percentage calculated on the basis of all the monomer units of the ethylene-1,3-diene copolymer.

[0030] According to another advantageous embodiment, the ethylene-1,3-diene copolymer comprises 65% to 90% mol of ethylene units, particularly 65% ​​to 85% mol of ethylene units, the mol percent being calculated on the basis of all the monomer units of the ethylene-1,3-diene copolymer. More advantageously, the ethylene-1,3-diene copolymer comprises 65% to 80% mol of ethylene units, the mol percent being calculated on the basis of all the monomer units of the ethylene-1,3-diene copolymer.

[0031] According to yet another advantageous embodiment of the invention, the ethylene-1,3-diene copolymer comprises 70% to 90% mol of ethylene units, particularly 70% to 85% mol of ethylene units, the molar percentage being calculated on the basis of all the monomer units of the ethylene-1,3-diene copolymer. More advantageously, the ethylene-1,3-diene copolymer comprises 70% to 80% mol of ethylene units, the molar percentage being calculated on the basis of all the monomer units of the ethylene-1,3-diene copolymer.

[0032] Since a copolymer of ethylene and a 1,3-diene is a copolymer of ethylene and a 1,3-diene, it also comprises 1,3-diene units resulting from the polymerization of a 1,3-diene. The expression "1,3-diene unit" or "diene unit" is known to refer to units resulting from the insertion of 1,3-diene by a 1,4-addition, a 1,2-addition, or a 3,4-addition in the case of isoprene, for example. The 1,3-diene units are those, for example, of a 1,3-diene having 4 to 12 carbon atoms, such as 1,3-butadiene, isoprene, 1,3-pentadiene, or aryl-1,3-butadiene. Preferably, the 1,3-diene is 1,3-butadiene or a mixture of 1,3-dienes, one of which is 1,3-butadiene. More preferably, the 1,3-diene is 1,3-butadiene, in which case the copolymer of ethylene and a 1,3-diene is a copolymer of ethylene and 1,3-butadiene, statistically preferred.

[0033] The copolymer of ethylene and a 1,3-diene can be obtained by various synthetic methods known to those skilled in the art, particularly depending on the desired microstructure of the ethylene-1,3-diene copolymer. Generally, it can be prepared by copolymerization of at least one 1,3-diene, preferably 1,3-butadiene, and ethylene, using known synthetic methods, particularly in the presence of a catalytic system comprising a metallocene complex. Examples include catalytic systems based on metallocene complexes, which are described in documents EP 1 092 731, WO 2004035639, WO 2007054223, and WO 2007054224 on behalf of the Applicant. The copolymer of ethylene and a 1,3-diene, including when it is statistical, can also be prepared by a process using a preformed type catalytic system such as those described in documents WO 2017093654 Al, WO 2018020122 Al and WO 2018020123 Al. Advantageously, the copolymer of ethylene and a 1,3-diene is statistical and is preferably prepared by a semi-continuous or continuous process as described in documents WO 2017103543 Al, WO 201713544 Al, WO 2018193193 and WO 2018193194.

[0034] The copolymer of ethylene and a 1,3-diene preferably contains units of formula (I) or units of formula (II). CH»--'CH, ■CM “CH / \ -CH2-CH(CH=CH2)- (Hj

[0035] The presence of a saturated 6-member cyclic motif, 1,2-cyclohexanediyl, of formula (I) in the copolymer can result from a series of very specific insertions of ethylene and 1,3-butadiene in the polymer chain during its growth. When the ethylene-1,3-diene copolymer comprises units of formula (I) or units of formula (II), the molar percentages of units of formula (I) and units of formula (II) in the highly saturated diene elastomer, respectively o and p, preferably satisfy the following equation (eq. 1) or equation (eq. 2), o and p being calculated on the basis of all the monomer units of the ethylene-1,3-diene copolymer.

[0036] 0 < o+p < 30 (eq. 1) 0 < o+p < 25 (eq. 2)

[0037] Preferably, the ethylene-1,3-diene copolymer comprises formula units (I) in a molar proportion greater than 0% and less than 15%, more preferably less than 10% molar, the molar percentage being calculated on the basis of all the monomer units of the ethylene-1,3-diene copolymer. Isoprene elastomer

[0038] The rubber composition of the composite according to the invention has as its essential characteristic of comprising at least one isoprene elastomer.

[0039] By "isoprene elastomer" is meant a homopolymer or copolymer of isoprene, in other words a diene elastomer selected from the group consisting of natural rubber (NR) which can be plasticized or peptized, the polyisoprenes of synthesis (IR), the various isoprene copolymers, in particular isoprene-styrene (SIR), isoprene-butadiene (BIR) or isoprene-butadiene-styrene (SBIR) copolymers, and mixtures of these elastomers.

[0040] Preferably, the isoprene elastomer is chosen from the group consisting of synthetic polyisoprenes, natural rubber, isoprene copolymers and mixtures thereof, preferably from the group consisting of natural rubber, polyisoprenes comprising a cis 1,4 linkage mass percentage of at least 90%, more preferably at least 98%, relative to the mass of the isoprene elastomer and mixtures thereof. Most preferably, the isoprene elastomer is natural rubber.

[0041] Preferably, the rubber composition of the composite according to the invention comprises at least 50 parts per annum of isoprenoid elastomer. Preferably, the proportion of isoprenoid elastomer in the rubber composition is greater than 55 parts per annum and less than or equal to 70 parts per annum.

[0042] The proportion of ethylene copolymer and a 1,3-diene useful for the purposes of the invention, in particular ethylene copolymer and 1,3-butadiene in the rubber composition, preferably varies in a range of 10 to 40 parts per cent.

[0043] Advantageously, the rubber composition comprises 10 to 40 parts per annum of ethylene and 1,3-diene copolymer, in particular ethylene and 1,3-butadiene copolymer, and 60 to 90 parts per annum of isoprene elastomer. Inorganic filler

[0044] The rubber composition of the composite according to the invention comprises at least 30 parts of a reinforcing inorganic filler.

[0045] In the present application, "reinforcing inorganic filler" should be understood, by definition, as any inorganic or mineral filler (regardless of its color and whether of natural or synthetic origin), also called "white" filler, "light" filler 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, a rubber composition intended for the manufacture of pneumatic tires, in other words, capable of replacing, in its reinforcing function, a conventional carbon black of pneumatic grade; such a filler is generally characterized, in a known way, by the presence of hydroxyl groups (-OH) on its surface.

[0046] Inorganic reinforcing fillers are suitable in particular mineral fillers of the siliceous type, especially silica (SiO2), or of the aluminous type, especially alumina (Al2O3).

[0047] Preferably, the reinforcing inorganic filler is silica. The silica used can be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenated silica having a BET surface as well as a surface specific CT AB 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 silicas "Ultrasil 7000" and "Ultrasil 7005" from the company Degussa, the silicas "Zeosil 1165MP", "1135MP" and "1115MP" from the company Rhodia, the silica "Hi-Sil EZ150G" from the company PPG, the silicas "Zeopol 8715", "8745" and "8755" from the company Huber, the silicas with high specific surface area as described in application WO 03 / 16837.

[0048] The physical state of the reinforcing inorganic filler is irrelevant, whether it is in the form of powder, microbeads, 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.

[0049] The reinforcing inorganic filler used, in particular if it is silica, preferably has a BET surface area of ​​between 45 and 400 m2 / g, more preferably between 60 and 300 m2 / g.

[0050] Preferably, the rubber composition of the composite according to the invention comprises from 30 to 150 parts, preferably from 35 to 100 parts of silica.

[0051] To couple the reinforcing inorganic filler to the elastomer, optionally a coupling agent (or bonding agent) at least bifunctional can be used in a known manner to ensure a sufficient connection, of a chemical and / or physical nature, between the inorganic filler (surface of its particles) and the elastomer, in particular organosilanes, or bifunctional polyorganosiloxanes.

[0052] In particular, polysulfide silanes, called "symmetric" or "asymmetric" depending on their particular structure, can be used, as described for example in applications WO03 / 002648 (or US 2005 / 016651) and WO03 / 002649 (or US 2005 / 016650).

[0053] Examples of polysulfurized silanes include, in particular, polysulfides (notably disulfides, trisulfides or tetrasulfides) of bis-(alkoxyl(Cl-C4)-alkyl(Cl-C4)silyl-alkyl(Cl-C4)), such as bis(3-trimethoxysilylpropyl) or bis(3-triethoxysilylpropyl) polysulfides. Among these compounds, bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT, with the formula [(C2H5O)3Si(CH2)3S2]2, and bis-(triethoxysilylpropyl) disulfide, abbreviated TESPD, with the formula [(C2H5O)3Si(CH2)3S]2, are particularly useful. As preferential examples, we will also cite the polysulfides (in particular disulfides, trisulfides or tetrasulfides) of bis-(monoalkoxyl(Cl-C4)-dialkyl(Cl-C4)silylpropyl), more specifically the bis-monoethoxydimethylsilylpropyl tetrasulfide as described in the US patent application 2004 / 132880.

[0054] As a coupling agent other than polysulfurized alkoxysilane, mention shall be made in particular of bifunctional POS (polyorganosiloxanes) or hydroxysilane polysulfides as described in patent applications WO 02 / 30939 and WO 02 / 31041, or silanes or POS bearing azo-dicarbonyl functional groups, as described for example in patent applications WO 2006 / 125532, WO 2006 / 125533, WO 2006 / 125534.

[0055] In the elastomeric compositions according to the invention, the coupling agent content is preferably in the range of 5 to 60% by weight relative to the amount of silica, preferably in the range of 15 to 50% by weight relative to the amount of silica, and most preferably in the range of 20 to 40% by weight relative to the amount of silica. These levels have proven particularly advantageous for obtaining the properties of the composites according to the invention.

[0056] The rubber composition of the composite according to the invention may also include carbon black.

[0057] All carbon blacks are suitable as carbon blacks, particularly those of the HAF, ISAF, and SAF types conventionally used in tires (so-called tire-grade blacks). Among these, carbon blacks reinforcing in the 100, 200, or 300 series (ASTM grades) are particularly suitable, such as NI 15, N134, N234, N326, N330, N339, N347, and N375, or, depending on the intended application, blacks in higher series (e.g., N660, N683, N772). Carbon blacks could, for example, already be incorporated into an isoprene elastomer in the form of a masterbatch (see, for example, applications WO 97 / 36724 or WO 99 / 16600). The specific surface area BET of carbon blacks is measured according to standard D6556-10 [multipoint method (minimum 5 points) - gas: nitrogen - relative pressure range P / P0: 0.1 to 0.3].

[0058] Preferably, the rubber composition of the composite according to the invention does not include carbon black, or includes less than 10 parts per annum, preferably less than 5 parts per annum. Crosslinking system

[0059] The rubber composition of the composite according to the invention includes a crosslinking system.

[0060] The crosslinking system may be based on either sulfur, or sulfur donors and / or peroxide and / or bismaleimides. Preferably, the crosslinking system is a vulcanization system, that is, a system based on sulfur (or a sulfur-donating agent) and a vulcanization accelerator. Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur, in particular accelerators, may be used as a vulcanization accelerator. of the thiazole type and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. Examples of such accelerators include the following sulfenamide compounds: N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide ("TBBS") and mixtures of these compounds.

[0061] Sulfur is used at a preferential rate of between 0.3 and 10 parts per annum, more preferably between 0.3 and 5 parts per annum. The primary vulcanization accelerator is used at a preferential rate of between 0.5 and 10 parts per annum, more preferably between 0.5 and 5 parts per annum.

[0062] Preferably, the composite composition according to the invention comprises a metal oxide and a stearic acid derivative, the ratio of the metal oxide to stearic acid derivative, by weight, being greater than 2. This preferred ratio ensures good adhesion to the reinforcing element embedded in the rubber composition. The metal oxide is preferably zinc oxide.

[0063] The rubber composition of the composite according to the invention preferably comprises a vulcanization accelerator. The vulcanization accelerator is used at a preferential rate such that the sulfur / vulcanization accelerator mass ratio is less than or equal to 5, preferably less than or equal to 4.

[0064] Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur can be used as an accelerator, in particular accelerators of the thiazole type and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. Examples of such accelerators include the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-ter-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds.

[0065] Crosslinking (or curing), where applicable vulcanization, is carried out in a known manner at a temperature generally between 130°C and 200°C, for a sufficient time which can vary for example between 5 and 90 min depending in particular on the curing temperature, the crosslinking system adopted and the crosslinking kinetics of the composition considered. Various additives

[0066] The rubber composition of the composite according to the invention may also include all or part of the usual additives commonly used in the com positions of elastomers intended for use in a vehicle tire, conveyor belt or belt, such as processing agents, plasticizers, pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants.

[0067] Suitable plasticizers include all plasticizers conventionally used in tires. These include preferably non-aromatic or very weakly aromatic oils selected from the group consisting of naphthenic oils, paraffinic oils, MES oils, TDAE oils, vegetable oils, ether plasticizers, and ester plasticizers.

[0068] Preferably, the rubber composition comprises less than 10 parts, preferably less than 5 parts, of plasticizer.

[0069] The rubber composition can be manufactured in suitable mixers, using two successive preparation phases according to a general procedure well known to those skilled in the art: a first thermomechanical working or mixing phase (sometimes referred to as the "non-productive" phase) at high temperature, up to a maximum temperature between 110°C and 190°C, preferably between 130°C and 180°C, followed by a second mechanical working phase (sometimes referred to as the "productive" phase) at a lower temperature, typically below 110°C, for example between 40°C and 100°C, a finishing phase during which the sulfur or sulfur donor and the vulcanization accelerator are incorporated.

[0070] By way of example, the first (non-productive) phase is carried out in a single thermomechanical step during which all the necessary constituents, any additional processing agents, and other miscellaneous additives, with the exception of sulfur and the vulcanization accelerator, are introduced into a suitable mixer such as a conventional internal mixer. The total mixing time in this non-productive phase is preferably between 1 and 15 minutes. After the mixture thus obtained during the first non-productive phase has cooled, the sulfur and the vulcanization accelerator are then incorporated at low temperature, generally in an external mixer such as a roller mixer; the mixture is then blended (productive phase) for a few minutes, for example, between 2 and 15 minutes.

[0071] The final composition thus obtained is then calendered, for example in the form of a sheet or plate, particularly for characterization in the laboratory, or extruded, for example to form a rubber profile used for the manufacture of semi-finished products such as a tire reinforcement layer. Reinforcement element

[0072] The composite according to the invention comprises at least one reinforcing element embedded in the rubber composition.

[0073] By "embedded", it is understood that the reinforcing element is totally covered by the com- rubber position, with the possible exception of the composite cutting areas.

[0074] A reinforcing element is understood to be an element that provides mechanical reinforcement to a matrix in which this reinforcing element is intended to be embedded. The reinforcing element comprises a wire element.

[0075] The wire element may be metallic or textile. A wire element is defined as an element having a length at least 10 times greater than the longest dimension of its cross-section, regardless of the shape of the latter: circular, elliptical, oblong, polygonal, and in particular rectangular, square, or oval. In the case of a rectangular cross-section, the wire element has the shape of a strip.

[0076] A metallic wire element can be a basic metallic monofilament. Such a basic metallic monofilament comprises a steel core, optionally coated with one or more layers of a coating that can be metallic and / or based on a non-metallic adhesive composition.

[0077] The metallic cladding comprises a metal selected from zinc, copper, tin, cobalt, and alloys of these metals. Examples of alloys of these metals include brass and bronze. The core steel is a carbon steel comprising between 0.1% and 1.2% carbon by mass, at most 11% chromium by mass, and less than 1% by mass of each of the following elements: manganese, silicon, aluminum, boron, cobalt, copper, molybdenum, nickel, niobium, titanium, tungsten, vanadium, zirconium, phosphorus, sulfur, and nitrogen, the remainder being composed of iron and unavoidable impurities resulting from the manufacturing process. The steel may exhibit a pearlitic, ferritic, austenitic, bainitic, or martensitic microstructure, or a microstructure resulting from a mixture of these microstructures.

[0078] The elementary metallic monofilament exhibits a mechanical strength ranging from 1000 MPa to 5000 MPa. Such mechanical strengths correspond to the steel grades commonly encountered in the field of tires, namely, grades NT (Normal Tensile), HT (High Tensile), ST (Super Tensile), SHT (Super High Tensile), UT (Ultra Tensile), UHT (Ultra High Tensile) and MT (Mega Tensile), the use of high mechanical strengths possibly allowing for improved reinforcement of the matrix in which the reinforcing element is intended to be embedded and a reduction in the weight of the matrix thus reinforced.

[0079] In the case where the elementary metallic monofilament has a circular cross-section, the diameter of these elementary metallic monofilaments preferentially ranges from 0.05 mm to 0.50 mm.

[0080] A metallic wire element can be an assembly of several elementary metallic monofilaments as described above, assembled together in a helix, for example by cabling or twisting the elementary metallic monofilaments to form, for example, layered cables comprising several concentric layers of metallic elemental monofilaments or stranded cables, each strand comprising several concentric layers of metallic elemental monofilaments. Optionally, and as described in WO2005071157, such a metallic wire element comprises a layer based on a polymer composition, preferably a composition comprising an elastomer, this layer being disposed between two layers of metallic elemental monofilaments of the coated cable or of a strand of the stranded cable.

[0081] A textile filament element may be a basic textile monofilament optionally coated with one or more layers of a coating based on an adhesive composition. This basic textile monofilament is obtained, for example, by melt spinning, solution spinning, or gel spinning. Each basic textile monofilament is made of an organic material, in particular a polymer, or an inorganic material, such as glass or carbon. The polymeric materials may be of the thermoplastic type, such as aliphatic polyamides, in particular polyamide 6-6, and polyesters, in particular polyethylene terephthalate. The polymeric materials may be of the non-thermoplastic type, such as aromatic polyamides, in particular aramid, and cellulose, whether natural or artificial, in particular rayon.

[0082] A textile fiber element can be an assembly of several elementary textile monofilaments as defined above. In a first variant, the assembly comprises 2 to 7 elementary textile monofilaments, each having a substantially circular cross-section with a diameter ranging, for example, from 0.10 mm to 0.50 mm. In a second variant, the assembly comprises more than 10 elementary textile monofilaments, preferably more than 100 elementary textile monofilaments, and more preferably more than 500 elementary textile monofilaments, each having a substantially circular cross-section with a diameter ranging, for example, from 2 µm to 100 µm. In the first and second variants, the assembly formed is commonly called a strand.

[0083] A textile yarn element can also be an assembly of several assemblies or strands as defined above. In one embodiment, the materials from which the elementary textile monofilaments of each assembly or strand are made are identical. In another embodiment, the materials from which the elementary textile monofilaments of each assembly or strand are made are different, the textile yarn element then being commonly called a hybrid textile yarn element.

[0084] In one embodiment, whether in the case of a metallic or textile wire element, the layer based on a non-metallic adhesive composition is formed by a layer of an adhesion primer that improves the adhesion of the wire element, for example, to an elastomeric matrix. Such adhesion primers are those commonly used by those skilled in the art for pre-gluing certain Textile fibers (particularly polyester fibers, e.g., PET, aramid, or aramid / nylon fibers). For example, an epoxy-based primer, especially one based on polyglycerol polyglycidyl ether, can be used. A blocked isocyanate-based primer can also be used.

[0085] In another embodiment, whether in the case of a metallic or textile wire element, the layer based on a non-metallic adhesive composition is formed by a layer based on a resin and an elastomer latex. Examples include RFL (Resorcinol-Formaldehyde-Latex) type adhesive compositions, as well as adhesive compositions such as those described in WO2015118041.

[0086] In yet another embodiment, whether in the case of a metallic or textile wire element, there may be a layer of an adhesion primer as described above and coating the wire element, this layer of adhesion primer itself being coated with a layer based on a resin and a latex of one or more elastomers as described above.

[0087] In one embodiment, the reinforcing element comprises a wire element and optionally a sheath covering the wire element individually or several wire elements collectively. The sheath may comprise one or more layers, each layer being based on a polymeric composition, for example a [thermoplastic] composition or [as described in WO2010 / 136389, WO2010 / 105975, WO2011 / 012521, WO2011 / 051204, WO2012 / 016757, WO2012 / 038340, WO2012 / 038341, WO2012 / 069346, WO2012 / 104279, WO2012 / 104280 and WO2012 / 104281]. In this embodiment, the polymer composition of each layer of the sheath is different from the composition based on the matrix in which the sheathed wire element(s) is intended to be embedded.

[0088] In another embodiment, the reinforcing element may be a knit or a fabric.

[0089] A knit is an assembly of yarn elements as defined above and comprising stitches formed by one or more of these yarn elements. Each stitch comprises a loop interlaced with another loop. Examples include jersey or English rib knits for knitted fabrics and charmeuse or atlas knits for knitted fabrics with cast-on stitches.

[0090] A fabric is an assembly of a first family of yarn elements, called warp yarn elements, substantially parallel to each other, and a second family of yarn elements, called weft yarn elements, substantially parallel to each other. Preferably, the yarn elements of the first family are substantially perpendicular to the yarn elements of the second family.

[0091] In the embodiment of the composite in which each reinforcing element is a reinforcing wire element, the reinforcing wire elements are arranged parallel to each other and embedded, for example by calendering, in the composition of rubber. This results in a so-called straight sheet, in which the reinforcing wire elements of the sheet are parallel to each other and parallel to a principal direction of the sheet. Then, if necessary, portions of each straight sheet are cut at a cutting angle and these portions are joined together to obtain a so-called angled sheet, in which the reinforcing wire elements of the sheet are parallel to each other and form an angle with the principal direction of the angled sheet, the angle formed with the principal direction then being equal to the cutting angle. Pneumatic

[0092] The vehicle tire, another object of the invention, comprises a composite according to the invention. Preferably, the tire comprises a reinforced layer made of a composite according to the invention.

[0093] The composite and the bandage according to the invention may be in the raw state (i.e., before crosslinking) or in the cured state (i.e., after crosslinking). Examples Preparation of rubber compositions

[0094] Seventeen Cl to C-17 rubber compositions, the detailed formulation of which is shown in Tables 1 and 2, were prepared in the following manner:

[0095] The elastomers, the organic or inorganic filler (carbon black or silica), and the various other ingredients, with the exception of sulfur and the vulcanization accelerator, are successively introduced into an internal mixer (final filling level: approximately 70% by volume), the initial tank temperature of which is approximately 80°C. A thermomechanical process (non-productive phase) is then carried out in a single step, lasting approximately 3 to 4 minutes in total, until a maximum "drop" temperature of 165°C is reached. The resulting mixture is collected, cooled, and then the sulfur and the vulcanization accelerator are incorporated in a mixer (homo-finisher) at 30°C, mixing everything together (productive phase) for an appropriate time (for example, about ten minutes).

[0096] The compositions thus obtained are then calendered either in the form of plates (2 to 3mm thick) or thin sheets of rubber for the measurement of their physical or mechanical properties, or extruded to form, for example, a profile for a tire.

[0097] The rubber compositions, with the exception of compositions Cl, C-6 and C-10, contain a highly saturated diene elastomer with a molar content of ethylene greater than 50% and natural rubber, in this case comprising 74 molar ethylene units. Tests and measurements

[0098] Measurement of Mooney viscosity (or Mooney plasticity)

[0099] An oscillating consistometer as described in French standard NF T 43-005 (1991) is used. The Mooney plasticity measurement is performed according to the following principle: the composition in its raw state (before firing) is molded in a cylindrical chamber heated to 100°C. After one minute of preheating, the rotor rotates inside the test specimen at 2 revolutions per minute, and the torque required to maintain this rotation is measured after 4 minutes of rotation. The Mooney plasticity (ML 1+4) is expressed in "Mooney units" (MU, with 1 MU = 0.83 Newton-meters). The lower the Mooney value, the lower the viscosity before firing and the better the processability of the composition.

[0100] Tensile tests

[0101] The tests were carried out in accordance with French standard NF T 46-002 of September 1988. All tensile measurements were carried out under normal temperature (23±2°C) and humidity (50+5% relative humidity) conditions, according to French standard NF T 40-101 (December 1979).

[0102]

[0103] The nominal secant modulus calculated by reducing to the initial section of the specimen (or apparent stress, in MPa) at 10% elongation, noted MAio, was measured in the second elongation (i.e. after accommodation) on samples baked for 60 minutes at 150°C.

[0104] Dynamic properties (after cooking)

[0105] The dynamic properties tan(d)max at 23°C are measured on a viscoelastic analyzer (Metravib VA4000), according to ASTM D 5992-96. The response of a cross-linked composite sample (cylindrical specimen 4 mm thick and 400 mm² cross-section) is recorded under sinusoidal loading in alternating simple shear at a frequency of 10 Hz, under defined temperature conditions, for example, 23°C, according to ASTM D 1349-99. A strain amplitude sweep is performed from 0.1 to 50% (forward cycle), then from 50% to 1% (reverse cycle). The results used are the loss factor tan(d). For the reverse cycle, the maximum observed value of tan(d), denoted tan(d)max, is indicated.

[0106] It is recalled that, as is well known to those skilled in the art, the value of tan(d)max at 23°C is representative of the hysteresis of the material and therefore of the rolling resistance: the lower tan(d)max at 23°C is, the lower the rolling resistance and therefore the improved.

[0107] Adhesion tests

[0108] Strips are manufactured consisting of three metal wires of diameter 0.32 mm placed parallel to each other embedded in a polyamide 6-6 sheath so as to obtain a strip of 0.46 mm thickness and 1.45 mm width.

[0109] The strip is coated with RFL glue and then embedded in the tested rubber composition.

[0110] To test the adhesion of the tested rubber composition to the strip, a measurement was carried out according to ASTM D2229.

[0111] Adhesion levels are characterized by measuring the so-called pull-off force (denoted Fmax) required to detach the strip from the test specimen. The results are expressed on a scale of 100, with a value greater than 100 indicating a pull-off force greater than that of the reference specimen.

[0112] copolymer of ethylene and a 1,3-diene

[0113] The ethylene-1,3-diene copolymer used in the following examples is prepared according to the following procedure:

[0114] In a 70 L reactor containing methylcyclohexane (64 L), ethylene (5600 g), and 1,3-butadiene (2948 g), butylloctylmagnesium (BOMAG) solution is added to the methylcyclohexane and the catalytic system. The Mg / Nd ratio is 6.2. The volume of the catalytic system solution introduced is 840 mL, with an Nd concentration of 0.0065 M. The reaction temperature is regulated at 80°C, and the polymerization reaction is initiated. The polymerization reaction proceeds at a constant pressure of 8.3 bar. The reactor is fed with ethylene and 1,3-butadiene in a molar ratio of 73 / 27 throughout the polymerization process. The polymerization reaction is stopped by cooling, degassing the reactor, and adding ethanol. An antioxidant is added to the polymer solution. The copolymer is recovered after steam stripping and drying to a constant mass.The polymerization time is 225 minutes. The weighed mass (6.206 kg) allows the average catalytic activity of the catalytic system to be determined, expressed in kilograms of polymer synthesized per mole of neodymium metal per hour (kg / mol.h). The copolymer has a ML (1+4) value at 100°C of 62.

[0115] The catalytic system is a preformed catalytic system. It is prepared in methylcyclohexane from a metallocene, [Me2Si(Flu)2Nd(q-BH4)2Li(THF)] at 0.0065 mol / L, a co-catalyst, butylmagnesium (BOMAG) with a BOMAG / Nd molar ratio of 2.2, and a preforming monomer, 1,3-butadiene with a 1,3-butadiene / Nd molar ratio of 90. The medium is heated to 80°C for 5 hours. It is prepared according to a preparation method in accordance with paragraph II.1 of patent application WO 2017093654 AL

[0116] The copolymer of ethylene and a 1,3-diene obtained, a copolymer of ethylene and 1,3-butadiene, is an ethylene-butadiene elastomer, referred to hereafter as "EBR". Example 1

[0117] In this example, the proportion of EBR in the NR-EBR blend is varied. The evolution of the stiffness / hysteresis trade-off (MAi0 / tan(d) ratio) is evaluated. The results are expressed as a base of 100, with the value of 100 being assigned, for each series containing a given silica content, to the stiffness / hysteresis trade-off of the composition not containing EBR.

[0118] A result greater than 100 indicates that the composition of the example considered has a higher ratio than the control.

[0119] [Tables 1] Constituents C-1 C-2 03 C-4 C-5 C-6 C-7 C-8 C-9 CW C-11 C-12 C-13 Natural Rubber! 100 90 80 70 50 100 90 80 70 100 99 80 70 EBR G) o IC 20 30 50 0 10 20 30 0 10 20 30 Silica {2} 45 45 45 45 45 40 40 40 40 35 35 35 35 SttoeSSS (3):6 16 16 16 16 14.2 i 4.2 14.2 14.2 12.4 12.4 12.4 17 4 DPG (4) 1.25 1.25 1.25 1 25 1 25 1 1 5 5 9.97 0.97 0.97 0 97 SPPD (5) 2 2 2 ? 2 ? 2 ? 2 2 2 2 2 Stearic acid (6) 1.5 ' 5 1.5 i 5 1 5 1 5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 ZnO{7} 4 4 4 4 4 4 4 4 4 4 4 4 4 4 CBS ¢8) 1.5 1.5 1.5 ' 5 1.5 1 1.5 ! 5 1.5 ' 5 1.5 1.5 1.5 Soluble sulfur 2 2.7 2 7 2 7 2 7 2 7 2 MAIO / tan 8 Results Base 100 100 113 128 144 179 100' 115 122 121 100 96 95 109

[0120] (1) Ethylene-1,3-butadiene copolymer containing 74 mol% of unit ethylene, 19% butadiene units in the form of 1,2 and 1,4 motifs and 7 mol% of 1,2-cyclohexanediyl motif, Tg -44°C

[0121] (2) “Zeosil 1165 MP” from Solvay-Rhodia in the form of micropearls, CTAB 160 m2 / g, precipitated silica

[0122] (3) Liquid silane triethoxysilylpropyltetrasulfide (TESPT) “Si69” of the company Evonik

[0123] (4) Diphenylguanidine “Perkacit DPG” from Flexsys

[0124] (5) N-(l,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine "Santaflex 6PPD" of the Flexys company

[0125] (6) Stearic acid “Pristerene 4931” from Uniqema

[0126] (7) Industrial grade zinc oxide from Umicore

[0127] (8) N-cyclohexyl-2-benzothiazol-sulfenamide “Santicure CBS” of the company Flexsys

[0128] It can be seen that the combination of an inorganic filler with a natural rubber blend and an EBR allows a very good expression of the stiffness / hysteresis compromise, this expression being all the more marked as the inorganic filler content is high.

[0129] For a lower inorganic filler content, the stiffness / hysteresis trade-off does not change significantly depending on the proportion of NR and EBR in the NR:EBR blend. Example 2

[0130] In this example, the evolution of the stiffness / hysteresis trade-off (MAio / tan(d) ratio) is evaluated by varying the proportion of EBR in the NR-EBR blend for a set of compositions including carbon black, and a set of compositions including silica. Compositions C-14 and C-17 are adjusted to exhibit substantially the same MAi0 stiffness and the same stiffness / hysteresis trade-off.

[0131] The results are expressed on a base of 100, with the value of 100 being assigned to the stiffness / hysteresis ratio and the MAi0 stiffness of the C-4 composition. A result greater than 100 indicates that the composition of the example considered has a higher stiffness (or a higher ratio) than the control.

[0132] [Tables2] Constituents C-14 C-15 016 C-4 C-17 C-5 Natural Rubber 90 80 70 70 60 50 EBR (1) 10 20 30 30 40 50 Silica (2) 45 45 45 Süane S169 (3) 16 16 16 N347 (9) 50 50 50 DPG (4) 1.25 1.25 1.25 6PPD (5) 1.5 1.5 1.5 2 2 2 Co Salt (10) 1.12 1.12 1.12 Stearic Acid (6) 0.65 0.65 0.65 1.5 1.5 1.5 ZnO (7) 9.4 9.4 9.4 4 4 4 CTP (11) 0.25 0.25 0.25 TBBS(12) 1 1 CBS (8) 1.5 1.5 1.5 Sulfur 7.6 7.6 7.6 2 2 2 Results MAY 0 (base 100) 102 110 113 100 113 130 MÀ1 D / tan S Base 100 102 105 107 100 108 124

[0133] (1) to (8) same as Table 1

[0134] (9) ASTM N347 Grade Carbon Black

[0135] (10) Cobalt salt

[0136] (11) Cyclohexylthiopthalimide (PVI)

[0137] (12) N-ter-butyl-2-benzothiazyl sulfenamide from Flexsys

[0138] In Table 2, the compositions have been adjusted so that the stiffness at 10% strain (MA10) is similar for the silica-based and carbon black-based mixtures. The results are expressed as a base of 100, based on composition C-4.

[0139] We see that the stiffness at 10% strain and the stiffness / hysteresis compromise of the C-14 (carbon black) and C-4 (silica) compositions are similar.

[0140] It is observed that the association of an inorganic filler with a natural rubber cut and an EBR allows a better expression of the stiffness / hysteresis compromise than the association of an organic filler with a natural rubber cut and an EBR.

[0141] [Tables3] G (J / m2) - Base IB© C-1 C-2 C-3 C-4 C-5 303 wo 100 itæ wo 100 503 138 250 227 606 idoo 614 313 75G 831 1618

[0142] The data presented in Table 3 are also shown in [Fig. 1].

[0143] The cracking rate increases with the energy release. These rates increase in essentially the same way as long as the EBR content is less than 50%. The cracking rate increases significantly faster when the EBR content reaches 50%. Example 3

[0144] In this example, the adhesion properties of different compositions are evaluated. Different rubber blocks are tested with the compositions shown in Table 4.

[0145] For compositions C1 to C14, the reference specimen is the specimen made of the rubber composition not containing EBR (C14). For compositions C6 and C8, the reference specimen is the specimen made of the rubber composition not containing EBR (C6). For compositions C14 and C16, the reference specimen is the specimen made of the C14 rubber composition.

[0146] [Tables4] Composition Cl C-2 C-4 C-6 C-8 C-14 C-16 Base 100 100 95 100 100 99 100 100

[0147] It is observed that for the compositions tested, the level of adhesion is not significantly impacted by the presence of EBR.

Claims

Demands

1. Composite comprising at least one reinforcing element embedded in a rubber composition, the rubber composition being based on at least one isoprene elastomer, an ethylene copolymer and a 1,3-diene, the ethylene units in the copolymer representing more than 50 mole percent of the monomer units of the copolymer, at least 30 parts per cent of a reinforcing inorganic filler, and a crosslinking system, the rubber composition comprising from 10 to 40 parts per cent by weight of elastomer, ethylene copolymer and 1,3-diene.

2. Composite according to the preceding claim in which the rubber composition comprises a metal oxide and a stearic acid derivative, the ratio of the rate of metal oxide and stearic acid derivative, in parts, being greater than 2.

3. Composite according to any one of the preceding claims in which the rubber composition comprises less than 10 pc, preferably less than 5 pc of plasticizer.

4. Composite according to any one of the preceding claims wherein the copolymer of ethylene and a 1,3-diene comprises at least 60 mol% of ethylene units, preferably at least 65 mol% of ethylene units, more preferably at least 70 mol% of ethylene units.

5. Composite according to any one of the preceding claims wherein the 1,3-diene units of the ethylene copolymer and a 1,3-diene are those of a 1,3-diene having 4 to 12 carbon atoms, preferably those of 1,3-butadiene, isoprene, 1,3-pentadiene, aryl-1,3-butadiene and a mixture of these units.

6. Composite according to any one of the preceding claims wherein the reinforcing inorganic filler of the rubber composition is silica.

7. Composite according to the preceding claim in which the rubber composition comprises from 30 to 150 parts per annum of silica.

8. Composite according to any one of claims 6 or 7, wherein the rubber composition comprises a coupling agent having a content in the range of 5 to 60% by weight relative to the amount of silica, preferably in the range of 15 to 50% by weight relative to the amount of silica, and preferably in the range of 20 to 40% by weight relative to the amount of silica.

9. Composite according to any one of the preceding claims wherein the rubber composition does not comprise carbon black, or comprises less than 10 pc, preferably less than 5 pc.

10. Composite according to any one of the preceding claims wherein the reinforcing element comprises a textile or metallic wire element.

11. Composite according to the preceding claim in which the metallic wire element is a metallic elementary monofilament or an assembly of several metallic elementary monofilaments.

12. Composite according to claim 10 wherein the reinforcing element comprises a textile yarn element made of a thermoplastic or non-thermoplastic polymeric material.

13. Vehicle bandage comprising a composite according to any one of the preceding claims.

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