Elastomer compositions comprising a pyrolysis carbon black

Abstract

The present disclosure relates to an elastomer composition based on: - at least one highly saturated diene elastomer, the highly saturated diene elastomer being a copolymer of ethylene and a 1,3-diene containing ethylene units which represent at least 50 mol% of the monomer units of the copolymer, - a reinforcing filler comprising at least one pyrolysis carbon black; and - a crosslinking system.

Description

[0001] ELASTOMERIC COMPOSITIONS COMPRISING A PYROLYSIS CARBON BLACK

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to the field of reinforced elastomeric compositions, in particular intended for the manufacture of rubber articles, such as in particular semi-finished articles for pneumatic or non-pneumatic tires, in particular for vehicles carrying heavy loads.

[0004] TECHNOLOGICAL BACKGROUND

[0005] Ideally, the elastomeric compositions constituting the treads of pneumatic or non-pneumatic tires must meet a large number of technical requirements, often contradictory, including high wear resistance while providing the tire with low rolling resistance. To increase the rigidity of an elastomeric composition, it is known, for example, to increase the level of reinforcing fillers. However, this solution has the disadvantage of increasing the hysteresis of the elastomeric composition.

[0006] Furthermore, in recent years, limiting the environmental impact of the manufacture and use of tires has become a major issue for manufacturers in the sector.

[0007] Research and development initiatives to produce tires from recycled materials have multiplied. For example, it has been proposed to use pyrolysis carbon blacks as a total or partial replacement for conventional tire-grade carbon blacks used as a reinforcing filler in the elastomeric compositions constituting the tire, particularly treads. While this solution offers gains in hysteresis (rolling resistance), these are obtained at the cost of a reduction in rigidity, resulting in lower tire wear resistance.

[0008] The loss of rigidity observed by the use of pyrolysis carbon blacks can be compensated in particular by increasing the level of reinforcing filler in the elastomeric compositions. However, this increase in the level of reinforcing fillers causes an increase in the hysteresis of the composition and therefore a risk of penalizing the rolling resistance properties, in particular of a pneumatic or non-pneumatic tire.

[0009] There is therefore still a need to provide elastomeric compositions that reduce the environmental footprint, by incorporating recycled materials and which satisfy a stiffness / hysteresis compromise while maintaining other properties, these compositions being particularly useful for forming all or part of the tread of a pneumatic or non-pneumatic tire.

[0010] BRIEF DESCRIPTION OF THE INVENTION

[0011] The present invention relates to an elastomeric composition based on: at least one highly saturated diene elastomer, the highly saturated diene elastomer being a copolymer of ethylene and a 1,3-diene containing ethylene units which represent at least 50 mol% of the monomer units of the copolymer; a reinforcing filler comprising at least one pyrolysis carbon black; and a crosslinking system.

[0012] The present invention also relates to a rubber article comprising at least one such elastomeric composition, the article preferably being selected from the group consisting of hoses, pipes, seals, O-rings, transmission belts, engine mounts, insulators for electric cables, shoe soles, semi-finished articles for pneumatic tires, semi-finished articles for non-pneumatic tires, non-pneumatic tires and pneumatic tires.

[0013] Other aspects of the invention are as described below and in the claims.

[0014] DEFINITIONS

[0015] The expression "composition based on" means a composition comprising the mixture and / or the in situ reaction product of the different constituents used, some of these constituents being able to react and / or being intended to react with each other, at least partially, during the different phases of manufacture of the composition; the composition can thus be in a totally or partially crosslinked state or in a non-crosslinked state.

[0016] The expression "part by weight per hundred parts by weight of elastomer" (or pce) means the part by mass per hundred parts by mass of elastomer or rubber, the two terms being synonymous.

[0017] In this document, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0018] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​going from more than a to less than b (i.e., excluding the limits a and b) while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​going from a to b (i.e., including the strict limits a and b).

[0019] The compounds mentioned in the description may be of fossil or bio-sourced origin. In the latter case, they may be partially or totally derived from biomass or obtained from renewable raw materials derived from biomass. This includes polymers, plasticizers, fillers, etc.

[0020] By "tire intended to equip a vehicle carrying heavy loads" we mean generically any tire fitted to heavy goods vehicles, vans, metros, buses, civil engineering vehicles, agricultural vehicles, airplanes and other handling vehicles.

[0021] By "elastomer matrix" or "elastomeric matrix" is meant all of the elastomer(s) present in the elastomeric composition.

[0022] By "predominantly" or "in a majority capacity", it is meant, within the meaning of the present invention, that the compound is in the majority among the compounds of the same type in the composition, that is to say that it is the one which represents the largest quantity by mass among the compounds of the same type. In other words, the mass of this compound represents at least 51% of the total mass of the compounds of the same type in the composition. For example, in a system comprising a single elastomer, this is in the majority within the meaning of the present invention; and in a system comprising two elastomers, the majority elastomer represents more than half of the total mass of the elastomers, in other words the mass of this elastomer represents at least 51% of the total mass of the elastomers. In the same way, a so-called majority filler is that representing the largest mass among the fillers in the composition.In other words, the mass of this filler represents at least 51% of the total mass of fillers in the composition.

[0023] All glass transition temperature “Tg” values ​​are measured in a known manner by DSC (Differential Scanning Calorimetry) according to ASTM D3418 (2008).

[0024] Unless otherwise stated, 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. The total monomer units of the elastomer designates all the constituent repeating units of the elastomer which result from the insertion of the monomers into the elastomer chain by polymerization.

[0025] DETAILED DESCRIPTION OF THE INVENTION

[0026] Surprisingly, the inventors have discovered that the specific combination of at least one highly saturated diene elastomer as described below, and a reinforcing filler as described below and a crosslinking system makes it possible to obtain an elastomeric composition meeting the expressed needs. In particular, the elastomeric composition can be used in a pneumatic or non-pneumatic tire, in particular in a tread for a pneumatic or non-pneumatic tire fitted to vehicles carrying heavy loads. The proposed solution makes it possible to reduce the environmental footprint of tires by incorporating recycled materials and to obtain a good stiffness / hysteresis compromise (wear resistance / rolling resistance).

[0027] Thus, the present invention relates to an elastomeric composition based on: at least one highly saturated diene elastomer, the highly saturated diene elastomer being a copolymer of ethylene and a 1,3-diene containing ethylene units which represent at least 50 mol% of the monomer units of the copolymer; a reinforcing filler comprising at least one pyrolysis carbon black; and a crosslinking system.

[0028] The present invention also relates to a rubber article comprising at least one such elastomeric composition, the article preferably being selected from the group consisting of hoses, pipes, seals, O-rings, transmission belts, engine mounts, insulators for electric cables, shoe soles, semi-finished articles for pneumatic tires, semi-finished articles for non-pneumatic tires, non-pneumatic tires and pneumatic tires.

[0029] Other aspects of the invention are as described below and in the claims.

[0030] Highly saturated diene elastomer

[0031] The elastomeric composition useful in the context of the present invention comprises at least one highly saturated diene elastomer (i.e. one or more highly saturated diene elastomers), preferably random, the highly saturated diene elastomer being a copolymer of 1,3-diene units and ethylene units, the ethylene units representing at least 50 mol% of the monomer units of the copolymer.

[0032] In the remainder of the present application, the expression "highly saturated diene elastomer being a copolymer of 1,3-diene units and ethylene units, the ethylene units representing at least 50 mol% of the monomer units of the copolymer".

[0033] As is known, the term "ethylene unit" refers to the -(CH2-CH2)- unit resulting from the insertion of ethylene into the elastomer chain. The highly saturated diene elastomer is rich in ethylene units, since ethylene units represent at least 50 mol% of all the monomer units of the elastomer.

[0034] Unless otherwise indicated, the rates of units resulting from the insertion of a monomer into a copolymer such as the copolymer useful in the invention are expressed as a molar percentage relative to the total of the monomer units of the copolymer.

[0035] Preferably, the highly saturated diene elastomer is a random copolymer. Preferably, the highly saturated diene elastomer comprises at least 55 mol% of ethylene units, preferably at least 60 mol% of ethylene units, more preferably at least 65 mol% of ethylene units. In other words, the ethylene units in the highly saturated diene elastomer preferably represent at least 55 mol% of all the monomer units of the highly saturated diene elastomer, more preferably at least 60 mol% of all the monomer units of the highly saturated diene elastomer. Even more preferably, the ethylene units represent at least 65 mol% of all the monomer units of the highly saturated diene elastomer.

[0036] Preferably, the ethylene units in the highly saturated diene elastomer represent at most 90 mol% of all the monomer units of the highly saturated diene elastomer. More preferably, the ethylene units represent at most 85 mol% of all the monomer units of the highly saturated diene elastomer. Even more preferably, the ethylene units represent at most 80 mol% of all the monomer units of the highly saturated diene elastomer.

[0037] According to an advantageous embodiment, the highly saturated diene elastomer comprises from 55% to 90% mol of ethylene unit, particularly from 55% to 85% mol of ethylene unit, molar percentage calculated on the basis of all the monomer units of the highly saturated diene elastomer. More advantageously, the highly saturated diene elastomer comprises from 55% to 80% mol of ethylene unit, molar percentage calculated on the basis of all the monomer units of the highly saturated diene elastomer.

[0038] According to another advantageous embodiment, the highly saturated diene elastomer comprises from 60% to 90% mol of ethylene unit, particularly from 60% to 85% mol of ethylene unit, molar percentage calculated on the basis of all the monomer units of the highly saturated diene elastomer. More advantageously, the highly saturated diene elastomer comprises from 60% to 80% mol of ethylene unit, molar percentage calculated on the basis of all the monomer units of the highly saturated diene elastomer.

[0039] According to yet another advantageous embodiment, the highly saturated diene elastomer comprises from 65% to 90% mol of ethylene unit, particularly from 65% to 85% mol of ethylene unit, molar percentage calculated on the basis of all the monomer units of the highly saturated diene elastomer. More advantageously, the highly saturated diene elastomer comprises from 65% to 80% mol of ethylene unit, molar percentage calculated on the basis of all the monomer units of the highly saturated diene elastomer.

[0040] The highly saturated diene elastomer being a copolymer of ethylene and a 1,3-diene, it also includes 1,3-diene units resulting from the polymerization of a 1,3-diene. As is known, the expression "1,3-diene unit" refers to the units resulting from the insertion of the 1,3-diene by a 1,4-addition, a 1,2-addition or a 3,4-addition in the case of isoprene for example.

[0041] 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 highly saturated diene elastomer is a copolymer of ethylene and 1,3-butadiene, preferably random.

[0042] The highly saturated diene elastomer preferably contains units of formula (I) and / or units of formula (II):

[0043] -a CH(CH:H2)- (H)

[0044] For example, the copolymer of ethylene and 1,3-diene may be devoid of units of formula (I). In this case, it preferably contains units of formula (II).

[0045] The presence of saturated 6-membered cyclic unit, 1,2-cyclohexane unit, of formula (I) as monomer unit in the copolymer may result from a series of very specific insertions of ethylene and 1,3-butadiene into the polymer chain during its growth. When the highly saturated diene elastomer comprises units of formula (I) or units of formula (II), or units of formula (I) and units of formula (II) in the copolymer, the molar percentages of units of formula (I) and units of formula (II) in the copolymer, respectively o and p, preferably satisfy the following equation (eq. 1) or equation (eq. 2), where o and p are calculated on the basis of all the monomer units of the highly saturated diene elastomer:

[0046] 0 < o+p < 30 (eq. 1 )

[0047] 0 < o+p < 25 (eq. 2).

[0048] Preferably, the highly saturated diene elastomer comprises units of formula (I) in a molar ratio greater than 0% and less than 15%, more preferably less than 10% mol, molar percentage calculated on the basis of all the monomer units of the highly saturated diene elastomer.

[0049] According to a particularly preferred embodiment, the highly saturated diene elastomer contains 1,4-units of trans configuration (1,4-trans units). When the diene elastomer contains 1,4-trans units, the 1,4-trans units represent more than 50 mol% of the 1,4-units of the highly saturated diene elastomer, preferably more than 80 mol% of the 1,4-units of the highly saturated diene elastomer.

[0050] The highly saturated diene elastomer useful for the purposes of the invention may consist of a mixture of highly saturated diene elastomers which differ from each other by their microstructures or by their macrostructures.

[0051] The highly saturated diene elastomer can be obtained according to different synthesis methods known to those skilled in the art, in particular depending on the targeted microstructure of the highly saturated diene elastomer. Generally, it can be prepared by copolymerization of at least one 1,3-diene, preferably 1,3-butadiene, and ethylene and according to known synthesis methods, in particular in the presence of a catalytic system comprising a metallocene complex. Mention may be made in this respect of catalytic systems based on metallocene complexes, which catalytic systems are described in documents EP 1 092 731, WO 2004035639, WO 2007054223 and WO 2007054224 in the name of the Applicant. The highly saturated diene elastomer, including when it is random, can also be prepared by a process using a preformed type catalytic system such as those described in documents WO 2017093654 A1, WO 2018020122 A1 and WO 2018020123 A1.Advantageously, the highly saturated diene elastomer is random and is preferably prepared according to a semi-continuous or continuous process as described in documents WO 2017103543 A1, WO 201713544 A1, WO 2018193193 and WO 2018193194.

[0052] Preferably, the level of highly saturated diene elastomer in the elastomeric composition useful in the context of the invention is at least 50 parts by weight per hundred parts of elastomer of the elastomeric composition (phr). Preferably, the level of highly saturated diene elastomer in the elastomeric composition useful in the context of the present invention varies in a range from 70 to 100 phr or from 80 to 100 phr. More preferably, it varies in a range from 90 to 100 phr.

[0053] When the elastomeric composition does not consist exclusively of a highly saturated diene elastomer (100 phr), it comprises at least one other diene elastomer. This other elastomer is present in proportions of at most 50 phr (parts by weight per hundred parts of total elastomer), preferably at most 20 phr or at most 10 phr.

[0054] This other diene elastomer may be any homopolymer of a diene monomer, conjugated or not, having from 4 to 18 carbon atoms; or any copolymer of a diene, conjugated or not, having from 4 to 18 carbon atoms and at least one other monomer.

[0055] The other monomer may be an olefin other than ethylene or a diene, conjugated or not.

[0056] Suitable conjugated dienes are conjugated dienes having from 4 to 12 carbon atoms, in particular 1,3-dienes. More specifically; suitable conjugated dienes include, in particular, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C1-C5 alkyl)-1,3-butadienes such as, for example, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, an aryl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene.

[0057] Suitable olefins are vinylaromatic compounds having 8 to 20 carbon atoms and aliphatic α-monoolefins having 3 to 12 carbon atoms. Suitable vinylaromatic compounds are, for example, styrene, ortho-, meta-, para-methylstyrene, the commercial mixture "vinyl-toluene", para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene. Suitable aliphatic α-monoolefins are, in particular, acyclic aliphatic α-monoolefins having 3 to 18 carbon atoms.

[0058] This other diene elastomer can have any microstructure. It can be block, random, sequenced, microsequenced, and be prepared in emulsion or in solution. It can be coupled and / or star-shaped or even functionalized with a coupling and / or star-forming or functionalizing agent.

[0059] Preferably, this other diene elastomer used in the invention is chosen from the group of highly unsaturated diene elastomers consisting of polybutadienes (BR), synthetic polyisoprenes (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers. Such copolymers are more preferably chosen from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR) and isoprene-butadiene-styrene copolymers (SBIR).

[0060] It is understood that this other diene elastomer may be constituted by a mixture of diene elastomers which differ from each other by their microstructures, by their macrostructures or by the presence of a function, by the nature or the position of the latter on the elastomer chain.

[0061] Reinforcing charge

[0062] The elastomeric composition useful in the context of the present invention comprises a reinforcing filler, the reinforcing filler comprising at least one pyrolysis carbon black. In addition to the pyrolysis carbon black, the reinforcing filler may comprise one or more other reinforcing fillers.

[0063] Advantageously, the specific combination of at least one highly saturated diene elastomer as described above, and at least one pyrolysis black as described below surprisingly makes it possible to obtain an elastomeric composition having a good rigidity / hysteresis compromise (wear resistance / rolling resistance).

[0064] The term "reinforcing filler" means any type of filler known for its ability to reinforce an elastomeric composition which can be used in particular for the manufacture of tires, for example organic fillers such as virgin carbon black or pyrolysis carbon black, or inorganic fillers such as silica or alumina.

[0065] In addition to the pyrolysis carbon black, the elastomeric composition may therefore also comprise at least one second reinforcing filler different from the pyrolysis carbon black, this second reinforcing filler being chosen from the group consisting of silicas, aluminas and virgin carbon blacks.

[0066] A person skilled in the art will be able to adapt the total rate of reinforcing filler, including the rate of pyrolysis carbon black, according to the relevant use of the elastomeric composition.

[0067] In certain embodiments, the level of reinforcing filler in the elastomeric composition useful in the context of the invention is within a range from 25 to 85 phr, preferably from 30 to 75 phr or from 35 to 75 phr.

[0068] Preferably, the pyrolysis carbon black represents more than 30% by weight, more preferably represents more than 50% by weight, even more preferably represents more than 70% by weight, more preferably represents more than 90% by weight, of the total weight of the reinforcing filler.

[0069] Thus, preferably, the level of reinforcing filler in the elastomeric composition useful in the context of the invention is within a range from 25 to 85 phr, the pyrolysis carbon black representing more than 30% by weight, more preferably representing more than 50% by weight, more preferably still representing more than 70% by weight, more preferably representing more than 90% by weight of the total weight of the reinforcing filler.

[0070] Thus, more preferably, the level of reinforcing filler in the elastomeric composition useful in the context of the invention comprising at least one pyrolysis carbon black is within a range from 30 to 75 phr, the pyrolysis carbon black representing more than 30% by weight, more preferably representing more than 50% by weight, even more preferably representing more than 70% by weight, more preferably representing more than 90% by weight, of the total weight of the reinforcing filler.

[0071] In some embodiments, the reinforcing filler is solely pyrolysis carbon black. In some embodiments, the elastomeric composition comprises from 25 to 85 phr, preferably from 30 to 75 phr, of reinforcing filler, the reinforcing filler being pyrolysis carbon black. It should then be understood that the elastomeric composition, in this particular embodiment, comprises pyrolysis carbon black as the only reinforcing fillers (the elastomeric composition therefore does not comprise inorganic reinforcing fillers and other organic reinforcing fillers).

[0072] The reinforcing fillers may be as described below.

[0073] Pyrolysis carbon black

[0074] The elastomeric composition useful in the context of the invention comprises as reinforcing filler at least one pyrolysis carbon black.

[0075] For the purposes of the present invention, the term "pyrolysis carbon black" means a carbon black resulting from a process for the pyrolysis of a material comprising at least one carbon polymer and a carbon black, hereinafter the material to be pyrolyzed, for example in the context of the recycling of such a material. The physical state in which the material to be pyrolyzed is present is indifferent, whether in the form of powder, granules, strips, or any other form, in the crosslinked or non-crosslinked state.

[0076] Preferably, the material to be pyrolyzed may be recovered from manufactured articles or products generated during their manufacture / production (such as by-products or scraps); these manufactured articles may be chosen from the group consisting of pneumatic tires, non-pneumatic tires, industrial conveyor belts, transmission belts, rubber seals, rubber hoses, shoe soles and windshield wipers. Even more preferably, the pyrolysis carbon black that can be used in the context of the present invention is a carbon black obtained from a pyrolysis process in which the material to be pyrolyzed is derived from manufactured articles chosen from the group consisting of pneumatic tires and non-pneumatic tires.

[0077] Pyrolysis in the context of the present invention means any type of thermal decomposition in the absence of oxygen and whose raw material is the material to be pyrolyzed as defined above. Pyrolysis carbon blacks are therefore distinguished from so-called industrial and / or ASTM grade carbon blacks, also called virgin carbon blacks, in that the carbon raw material used for pyrolysis is a material comprising at least one carbon polymer and a carbon black and not materials derived from petroleum fractions or from coal or from oils of natural origin.

[0078] The pyrolysis carbon blacks that can be used in the context of the present invention are distinguished from known carbon blacks such as industrial and / or ASTM grade carbon blacks, in particular so-called “furnace” carbon blacks, also referred to below as “virgin carbon blacks”, in particular by a higher ash content.

[0079] Preferably, the pyrolysis carbon black usable in the context of the present invention has an ash content ranging from 5% to 30% by weight, more preferably ranging from 8% to 25% by weight, even more preferably ranging from 10% to 22% by weight, relative to the total weight of the pyrolysis carbon black.

[0080] Preferably, the pyrolysis carbon black usable in the context of the present invention has a sulfur content greater than 2% by weight, preferably ranging from 2.5% to 5% by weight, relative to the total weight of the pyrolysis carbon black.

[0081] Preferably, the pyrolysis carbon black usable in the context of the present invention has a zinc content greater than or equal to 2% by weight, preferably ranging from 2.5% to 8% by weight, relative to the total weight of the pyrolysis carbon black.

[0082] Preferably, the pyrolysis carbon black usable in the context of the present invention has a specific surface area STSA measured according to the ASTM D 6556-2021 standard within a range from 20 to 200 m 2 / g, more preferably ranging from 30 to 90 m 2 / g.

[0083] Preferably, the pyrolysis carbon black usable in the context of the present invention has a void volume measured according to standard ASTM D7854 (2018) and at a pressure of 50 MPa within a range from 30 to 60 ml / l 00g, more preferably from 35 to 55 ml / l 00g.

[0084] The ash content is determined by calcination in platinum capsules in a muffle furnace at 825°C according to the following protocol. A capsule is previously identified before each series of measurements and is tared to the nearest 0.1 mg and the mass is noted PO. In the capsule, 5 g of pyrolysis carbon black sample is introduced and weighed precisely to the nearest 0.1 mg; this mass is noted P1. The capsule and its contents are pre-calcined using a Bunsen burner until fumes appear and the product ignites. Once the product has completely burned, the capsule and its contents are introduced into a muffle furnace heated to 825 C for 1 h. After 1 h, the capsule is removed from the furnace and immediately placed in a desiccator at room temperature. When the capsule and the ash have returned to room temperature, the capsule is weighed again to obtain the mass P2.Finally, it is possible to obtain the ash content (% ash) using the formula below:.

[0085] % ash 100

[0086] The zinc content in the pyrolysis carbon black is determined after calcination of the sample, then recovery of the ash in an acid medium and determination by ICP-AES (inductively coupled plasma atomic emission spectroscopy). The ash is obtained by carrying out the above protocol. Approximately 100 mg of ash (test sample) is taken and placed in a PFA (perfluoroalkoxy) tube for a HotBIock hot plate. 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid and 0.5 mL of 40% hydrofluoric acid are then added. The tube is closed with its cap and heated at 130 C for 2 hours. After cooling, the contents are then transferred using ultrapure water into a 100 mL PTFE (polytetrafluoroethylene) volumetric flask already containing 2 g of boric acid (to neutralize the hydrofluoric acid). The volume is topped up with ultrapure water to the mark.The solution obtained is diluted by 100, by taking 1 mL in a 100 mL PFTE flask, previously containing 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, 0.5 mL of 40% hydrofluoric acid and 2 g of boric acid. This diluted solution is then filtered through a 0.45 pm GHP syringe filter before being analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Before analyzing the diluted solution, at least 5 standards are analyzed by ICP-AES at zinc concentrations of 0, 0.5, 1, 2 and 5 mg / L. These standards were prepared in 100 mL volumetric flasks, by diluting a certified commercial solution to a zinc concentration of 1 g / L.

[0087] These volumetric flasks contain 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, 0.5 mL of 40% hydrofluoric acid and 2 g of boric acid. The standard solutions are analyzed by ICP-AES at a wavelength of λZn = 202.613 nm. For each standard concentration (c), the intensity of the zinc signal IZn is plotted on a graph IZn = f(c), which corresponds to the calibration line (of type y = ax + b). The sample solution (diluted solution) of unknown concentration is then measured under the same conditions as the standards. The measured intensity is related to the concentration using the calibration line obtained previously. The concentration [c]ash in % by mass is thus obtained directly by the software, because the test portion and the volume have been previously recorded. The zinc concentration in pyrolysis black [c]black in mass % is obtained by the following equation: 300 * % ash

[0088] The determination of the sulfur content in pyrolysis carbon blacks is carried out by LECO furnace. LECO sulfur analyzers are designed to measure, in particular, the sulfur content in organic and / or inorganic materials by combustion and non-dispersive infrared detection. Before measuring the sulfur content on the sample, the boats are cleaned and the furnace calibrated. The LECO perimeter boats are previously cleaned: this involves analyzing the empty boat under the same conditions as the samples. The preparation of the calibration curve is done using a commercial standard called "BBOT" whose purity is greater than 99.99% and whose carbon (C), hydrogen (H), nitrogen (N), oxygen (O) and sulfur (S) content is guaranteed. This content is as follows: C%: 72.52; H% 6.09; N% 6.51; 0% 7.43 and S% 7.44. Approximately 10 ± 3, 20 ± 3 and 40 ± 3 mg of BBOT are weighed exactly in a pod.The standard / boat assembly is introduced into the combustion furnace, regulated at 1350 °C under pure oxygen. The combination of the furnace temperature and the analysis flow rate causes the combustion of the sample and the release of sulfur and / or carbon in the form of SO2(g). After a time of 20 s, oxygen begins to flow through the "lance" to accelerate the combustion of difficult-to-burn materials. The sulfur and / or carbon, in the form of SC>2(g), are carried by an oxygen flow through the infrared detection cells. The instrument software plots a straight line connecting the mass of standard introduced and the observed response (area) on the detector. This gives a calibration straight line. After carefully cleaning the sampling equipment, approximately 80 ± 5 mg of pyrolysis carbon black is weighed and introduced into a LECO furnace boat.The observed SO2 peak area is related to the concentration using the calibration line. The instrument software then calculates the mass % of sulfur in the sample using the mass of the sample introduced into the basket. Pyrolysis carbon blacks are marketed, for example, by BlackBear under the reference "BBCT30" or by Scandinavian Enviro Systems under the reference "P550".

[0089] Virgin carbon black

[0090] The elastomeric composition useful in the context of the invention may further comprise a carbon black different from pyrolysis carbon black, this carbon black also being called “virgin carbon black” because it is not produced from materials already comprising carbon black. Virgin carbon black is produced from materials derived from petroleum fractions or from coal or from oils of natural origin.

[0091] All carbon blacks are suitable as virgin carbon blacks, including carbon blacks conventionally used in tires or their treads, in particular industrial carbon blacks, more specifically so-called "furnace" carbon blacks.

[0092] Among the virgin carbon blacks, we will mention in particular the reinforcing virgin carbon blacks of the 100, 200, 300 series, or the 500, 600 or 700 series blacks (ASTM D-1765-2017 grades), such as for example blacks N115, N134, N234, N326, N330, N339, N347, N375, N550, N683, N772.

[0093] Virgin carbon blacks can be used in the isolated state, as commercially available, or in any other form, for example as a carrier for some of the rubber additives used. Virgin carbon blacks could for example already be incorporated into the diene elastomer, in particular isoprene in the form of a masterbatch (see for example applications WO97 / 36724-A2 or W099 / 16600-A1).

[0094] The elastomeric composition useful in the context of the invention may comprise a silica or an alumina (i.e. one or more silicas, respectively aluminas) which are reinforcing inorganic fillers.

[0095] By "reinforcing inorganic filler" is meant here any inorganic or mineral filler, whatever its color and origin (natural or synthetic), also called "white" filler, "clear" 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, an elastomeric composition intended for the manufacture of tires. As is known, certain reinforcing inorganic fillers can be characterized in particular by the presence of hydroxyl groups (-OH) on their surface.

[0096] Suitable reinforcing inorganic fillers are, in particular, mineral fillers of the siliceous type, preferably silica (SiC>2) or of the aluminous type, in particular alumina (AI2O3). The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET specific surface area and a CTAB specific surface area, both of less than 450 m 2 / g, preferably within a range of 30 to 400 m 2 / g, especially from 60 to 300 m 2 / g.

[0097] Any type of precipitated silica may be used, in particular highly dispersible precipitated silicas (called "HDS" for "highly dispersible" or "highly dispersible silica"). These precipitated silicas, whether highly dispersible or not, are well known to those skilled in the art. Examples include the silicas described in applications WO03 / 016215-A1 and WO03 / 016387-A1. Among the commercial HDS silicas, it is possible to use in particular the silicas "Ultrasil ® 5000GR", "Ultrasil ® 7000GR" from the company Evonik, the silicas "Zeosil ® 1085GR", "Zeosil® 1115 MP", "Zeosil® 1165MP", "Zeosil® Premium 200MP", "Zeosil® HRS 1200 MP" from the company Solvay.As non-HDS silica, the following commercial silicas can be used: silicas “Ultrasil ® VN2GR”, “Ultrasil ® VN3GR” from Evonik, silica “Zeosil® 175GR” from Solvay, silicas “Hi-Sil EZ120G(-D)”, “Hi-Sil EZ160G(- D)”, “Hi-Sil EZ200G(-D)”, “Hi-Sil 243LD”, “Hi-Sil 210”, “Hi-Sil HDP 320G” from PPG.

[0098] The BET specific surface area of ​​silica is determined in a known manner by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" Vol. 60, page 309, February 1938, more precisely according to the French standard NF ISO 9277 of December 1996 (multipoint volumetric method (5 points) - gas: nitrogen - degassing: 1 hour at 160°C - relative pressure range p / po: 0.05 to 0.17). The CTAB specific surface area of ​​silica is determined according to the French standard NF T 45-007 of November 1987 (method B).As other examples of inorganic fillers that can be used in elastomeric compositions, mention may also be made of mineral fillers of the aluminous type, in particular alumina (AI2O3), aluminum oxides, aluminum hydroxides, aluminosilicates, titanium oxides, silicon carbides or nitrides, all of the reinforcing type as described for example in applications WO99 / 28376-A2, WOOO / 73372-A1, WO02 / 053634-A1, W02004 / 003067-A1.

[0099] W02004 / 056915-A2, US6610261-B1 and US6747087-B2. Examples include the aluminas “Baikalox A125” or “CR125” (Baïkowski company), “APA-100RDX” (Condéa), “Aluminoxid C” (Evonik) or “AKP-G015” (Sumitomo Chemicals).

[0100] The physical state in which the reinforcing inorganic filler is presented is indifferent, whether in the form of powder, microbeads, granules, or even beads or any other suitable densified form. Of course, the term reinforcing inorganic filler also means mixtures of different reinforcing inorganic fillers, in particular silicas as described above.

[0101] Those skilled in the art will understand that, as a replacement for the reinforcing inorganic filler described above, a reinforcing filler of another nature could be used, provided that this reinforcing filler of another nature is covered with an inorganic layer such as silica, or else comprises functional sites on its surface, in particular hydroxyl sites, requiring the use of a coupling agent to establish the bond between this reinforcing filler and the diene elastomer.

[0102] To couple the reinforcing inorganic filler to the highly saturated diene elastomer, it is possible to use, in a well-known manner, an at least bifunctional coupling agent (or bonding agent) intended to ensure a sufficient connection, of a chemical and / or physical nature, between the inorganic filler (surface of its particles) and the diene elastomer. In particular, at least bifunctional organosilanes or polyorganosiloxanes are used. By "bifunctional", we mean a compound having a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the highly saturated diene elastomer.For example, such a bifunctional compound may comprise a first functional group comprising a silicon atom, said first functional group being capable of interacting with the hydroxyl groups of an inorganic filler and a second functional group comprising a sulfur atom, said second functional group being capable of interacting with the highly saturated diene elastomer.Preferably, the organosilanes are chosen from the group consisting of polysulfurized organosilanes (symmetrical or asymmetrical) such as bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated to TESPT, marketed under the name “Si69” by the company Evonik or bis-(triethoxysilylpropyl) disulfide, abbreviated to TESPD, marketed under the name “Si75” by the company Evonik, polyorganosiloxanes, mercaptosilanes, blocked mercaptosilanes, such as S-(3-(triethoxysilyl)propyl) octanethioate marketed by the company Momentive under the name “NXT Silane”. More preferably, the organosilane is a polysulfurized organosilane.

[0103] The skilled person can find examples of coupling agent in the following documents: WO 02 / 083782, WO 02 / 30939, WO 02 / 31041, WO 2007 / 061550, WO 2006 / 125532, WO 2006 / 125533, WO 2006 / 125534, US 6,849,754, WO 99 / 09036, WO 2006 / 023815, WO 2007 / 098080, WO 2010 / 072685 and WO 2008 / 055986.

[0104] The coupling agent content preferably represents from 0.5% to 15% by weight relative to the amount of reinforcing inorganic filler, preferably from 4 to 12%, more preferably from 6% to 10% by weight relative to the amount of reinforcing inorganic filler. Typically, the coupling agent level is less than 20 phr, preferably within a range from 6 to 17 phr, preferably from 8 to 15 phr. This level can easily be adjusted by a person skilled in the art according to the level of reinforcing inorganic filler used in the elastomeric composition.

[0105] The elastomeric composition may also contain, in addition to the coupling agents, coupling activators, agents for covering inorganic fillers or more generally processing aids capable, in a known manner, thanks to an improvement in the dispersion of the filler in the rubber matrix and a reduction in the viscosity of the compositions, of improving their processability in the raw state, these agents being, for example, hydrolyzable silanes such as alkylalkoxysilanes (in particular alkyltriethoxysilanes), polyols, polyethers (for example polyethylene glycols), primary, secondary or tertiary amines (for example trialkanol-amines), hydroxylated or hydrolyzable POS, for example α,β-dihydroxy-polyorganosiloxanes (in particular α,β-dihydroxy-polydimethylsiloxanes). Other organic fillers

[0106] The elastomeric composition useful in the context of the invention may comprise a reinforcing organic filler of functionalized polyvinyl type as described in applications WO2006 / 069792-A1, WO2006 / 069793-A1, WO2008 / 003434-A1 and WO2008 / 003435-A1.

[0107] Crosslinking system

[0108] The elastomeric composition useful in the context of the invention comprises a crosslinking system.

[0109] The crosslinking system may be any type of system known to those skilled in the art in the field of elastomeric compositions for tires. It may in particular be based on sulfur, and / or peroxide and / or bismaleimides.

[0110] Preferably, the crosslinking system is sulfur-based, in which case we speak of a vulcanization system.

[0111] Sulfur can be supplied in any form, including molecular sulfur, or a sulfur-donating agent.

[0112] A sulfur donor is any compound that releases sulfur atoms, combined or not in the form of a polysulfide chain, capable of being inserted into the polysulfide chains formed during vulcanization and bridging the elastomer chains. The sulfur content in the elastomeric composition is preferably less than 2 pce, preferably between 0.3 and 1.5 pce.

[0113] Any compound capable of acting as a vulcanization accelerator (primary or secondary) which can act as a vulcanization accelerator for diene elastomers in the presence of sulfur may be used, in particular accelerators of the thiazole type and their derivatives, accelerators of the sulfenamide type for primary accelerators, and accelerators of the guanidine, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate type for secondary accelerators. Guanidine is understood to mean any compound which contains the divalent radical -HN-C(=NH)-NH- . Guanidine is preferably diphenylguanidine. The vulcanization accelerator is used at a preferential rate of between 0.3 and 5 pce, more preferably between 0.5 and 2.5 pce.Examples of primary accelerators include sulfenamide compounds such as N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-tert-butyl-2-benzothiazyl sulfenamide ("TBBS"), and mixtures of these compounds. The primary accelerator is preferably a sulfenamide, more preferably N-cyclohexyl-2-benzothiazyl sulfenamide.

[0114] Examples of secondary accelerators include thiuram polysulfides, preferably thiuram disulfides such as tetraethylthiuram disulfide, tetrabutylthiuram disulfide ("TBTD"), tetrabenzylthiuram disulfide ("TBZTD") and mixtures of these compounds. The secondary accelerator is preferably a thiuram disulfide, more preferably tetrabenzylthiuram disulfide.

[0115] The primary accelerator is preferably a sulfenamide. When the primary vulcanization accelerator is a sulfenamide, it is preferably N-cyclohexyl-2-benzothiazyl sulfenamide.

[0116] The vulcanization accelerator is preferably a mixture of a primary accelerator and a secondary accelerator. The term "a primary accelerator" designates a single primary accelerator or a mixture of primary accelerators. Similarly, the term "a secondary accelerator" designates a single secondary accelerator or a mixture of secondary accelerators. When the vulcanization accelerator is a mixture of a primary accelerator and a secondary accelerator, the vulcanization accelerator is preferably a mixture of a sulfenamide and a thiuram disulfide or a mixture of a sulfenamide, a thiuram disulfide and a guanidine, the sulfenamide preferably being N-cyclohexyl-2-benzothiazyl sulfenamide, the thiuram disulfide preferably being tetrabenzylthiuram disulfide, and the guanidine preferably being diphenylguanidine.

[0117] As is well known, the vulcanization system may also comprise vulcanization activators such as metal oxides such as zinc oxide or fatty acids such as stearic acid. Common additives and processing agents

[0118] The elastomeric composition useful in the context of the invention may also comprise all or part of the usual additives and processing agents, known to those skilled in the art and usually used in elastomeric compositions for tires, such as, for example, plasticizing agents (such as plasticizing oils and / or plasticizing resins), non-reinforcing fillers, pigments, agents promoting green tack (i.e., tackifying agent), pro-oxidizing metal salts, protective agents such as anti-ozone waxes, chemical antiozonants, antioxidants, anti-fatigue agents, reinforcing resins (as described, for example, in application WO 02 / 10269).

[0119] Preferably, the level of plasticizing agent(s) in the elastomeric composition useful in the context of the invention is within a range from 0 to 20 pce, more preferably within a range from 0 to 10 pce.

[0120] Production of compositions

[0121] The elastomeric composition useful in the context of the invention is manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art:

[0122] - a first thermomechanical working or mixing phase (so-called "non-productive" phase), which can be carried out in a single thermomechanical step during which all the necessary constituents are introduced into a suitable mixer such as a conventional internal mixer (for example of the 'Banbury' type), in particular the highly saturated diene elastomer as defined above, the reinforcing filler(s) including pyrolysis carbon black, any other various additives, with the exception of the crosslinking system. The incorporation of the reinforcing filler into the highly saturated diene elastomer can be carried out in one or more stages by thermomechanical mixing. The non-productive phase is carried out at high temperature, up to a maximum temperature in a range from 110°C to 200°C, for a duration generally in a range from 2 to 10 minutes;

[0123] - a second phase of mechanical work (so-called "productive" phase), which is carried out in an external mixer such as a roller mixer, after cooling the mixture obtained during the first non-productive phase to a lower temperature, typically below 120°C, for example ranging from 40°C to 100°C. The crosslinking system is then incorporated, and everything is then mixed for a few minutes, for example from 5 to 15 min.

[0124] The final elastomeric composition thus obtained is then calendered, for example, in the form of a sheet or plate, in particular for characterization in the laboratory, or extruded in the form of a semi-finished (or profiled) rubber usable, for example, as a tread for a tire, in particular as a tread for a tire of a vehicle carrying heavy loads, in particular a heavy goods vehicle or a civil engineering vehicle.

[0125] The elastomeric composition can be either in the raw state (before crosslinking or vulcanization), or in the cured state (after crosslinking or vulcanization), can be a semi-finished product which can be used in a tire.

[0126] The crosslinking of the elastomeric composition can be carried out in a manner known to those skilled in the art, for example at a temperature in a range from 130°C to 200°C, preferably under pressure, for a sufficient time which can vary for example from 5 to 90 min.

[0127] Rubber goods

[0128] Another subject of the present invention relates to a rubber article comprising at least one elastomeric composition as defined above.

[0129] The rubber article can be any type of article such as a hose, a pipe, a gasket, an O-ring, a transmission belt, an engine mount, an insulation for electric cables, a shoe sole, a semi-finished article for pneumatic tires, a semi-finished article for non-pneumatic tires, a pneumatic tire or a non-pneumatic tire.

[0130] Preferably, the rubber article is chosen from the group consisting of semi-finished articles for pneumatic tires, semi-finished articles for non-pneumatic tires, pneumatic tires and non-pneumatic tires.

[0131] Semi-finished products for pneumatic tires or non-pneumatic tires are rubber products intended for the manufacture of pneumatic tires or non-pneumatic tires. This can be any type of rubber strip, such as treads, underlays, etc.

[0132] More preferably, the elastomeric composition as defined above useful in the context of the invention constitutes all or part of said semi-finished article.

[0133] Preferably, the semi-finished article for pneumatic tires or for non-pneumatic tires is a tread.

[0134] As is known, the tread of a pneumatic or non-pneumatic tire comprises a rolling surface intended to be in contact with the ground when the pneumatic or non-pneumatic tire rolls. The tread is provided with a sculpture comprising in particular sculpture elements or elementary blocks delimited by various grooves.

[0135] Advantageously, the elastomeric composition as defined above useful in the context of the invention is present in the tread of the pneumatic tire or non-pneumatic tire, preferably in the radially external part of the tread, intended to be in contact with the ground when the pneumatic or non-pneumatic tire rolls. Even more preferably, the elastomeric composition as defined above useful in the context of the invention constitutes all or part of the tread, in particular for pneumatic tires or for non-pneumatic tires.

[0136] The term "pneumatic tire" means a tire intended to form a cavity by cooperating with a support element, for example a rim, this cavity being capable of being pressurized to a pressure higher than atmospheric pressure.

[0137] In contrast, a "non-pneumatic tire" is a tire that supports the load of a vehicle by a means other than a pressurized inflation gas. Thus, a non-pneumatic tire is a toric body made of at least one polymeric material, intended to perform the function of a tire but without being subjected to inflation pressure. A non-pneumatic tire may be solid or hollow. A hollow non-pneumatic tire may contain air, but at atmospheric pressure, i.e. it does not have pneumatic rigidity provided by an inflation gas at a pressure higher than atmospheric pressure. Non-pneumatic tires are described for example in documents WO 03 / 018332 and FR2898077.

[0138] The pneumatic or non-pneumatic tires are intended to equip in particular vehicles of all types. Preferably, the rubber article according to the invention is a semi-finished article for a pneumatic tire, preferably a tread, such as a tread in particular consisting in whole or in part of at least one elastomeric composition as defined above. Even more preferably, the semi-finished article above is a semi-finished article for an industrial vehicle such as heavy goods vehicles, vans, agricultural vehicles, buses, metros, civil engineering vehicles, airplanes and other handling vehicles.

[0139] More preferably still, the rubber article according to the invention is a pneumatic tire comprising at least one elastomeric composition, in particular in its tread, said elastomeric composition constituting all or part of said tread. More preferably still, the rubber article is a pneumatic tire for industrial vehicles such as heavy goods vehicles, vans, agricultural vehicles, buses, metros, civil engineering vehicles, airplanes and other handling vehicles. The pneumatic tire can be manufactured according to any method well known to those skilled in the art.

[0140] Preferably, the rubber article is a pneumatic or non-pneumatic tire whose tread is made up in whole or in part of at least one elastomeric composition according to the invention.

[0141] The following examples are given for illustrative purposes, but should in no way be considered as limiting the present invention.

[0142] EXAMPLES

[0143] Measurement method

[0144] 1.1 Determination of the microstructure of elastomers

[0145] Copolymers of ethylene and 1,3-butadiene are characterized by NMR spectrometry 1 H, 13 C. NMR spectra are recorded on a Brüker Avance III 500 MHz Spectrometer equipped with a BBIz-grad 5 mm “broadband” cryoprobe. The NMR experiment 1 Quantitative H, uses a single 30° pulse sequence and a 5 second repetition delay between each acquisition. 64 to 256 accumulations are performed. The NMR experiment 13Quantitative C uses a 30° single-pulse sequence with proton decoupling and a 10-second repetition delay between each acquisition. 1024 to 10240 accumulations are performed. Two-dimensional experiments 1 H / 13 C are used for the purpose of determining the structure of polymers. The determination of the microstructure of copolymers is defined in the literature, according to the article by Llauro et al., Macromolecules 2001, 34, 6304-6311. NMR measurements are carried out at 25°C. The copolymers are dissolved in a deuterated solvent (approximately 25 mg of elastomer in 1 mL), generally deuterated chloroform (CDCh).

[0146] 1.2 Mooney Viscosity

[0147] Mooney viscosity is measured using an oscillating consistometer as described in ASTM D1646 (1999). The measurement is carried out according to the following principle: the sample analyzed in the raw state (i.e., before curing) is molded (shaped) in a cylindrical enclosure heated to a given temperature (100°C). After 1 minute of preheating, the rotor rotates within the specimen at 2 revolutions / minute and the torque needed to maintain this movement is measured after 4 minutes of rotation. Mooney viscosity (ML) is expressed in "Mooney units" (MU, with 1 MU = 0.83 Newton meters).

[0148] 1.3 Size exclusion chromatography (SEC / RI)

[0149] Size exclusion chromatography (SEC) allows the fractionation of polymer chains in a solvent according to their hydrodynamic volume. Like any chromatographic system, the technique is based on the elution of a solute (the polymer) through a column containing a stationary phase. The system is composed in this order: a solvent reservoir, a pumping system, an injector, a set of columns and detectors. The measurement chain is equipped with a Waters Alliance e2695 module and a Waters fRI410 refractometer.

[0150] The mobile phase is eluted with a flow rate of 1 mL / min. The polymer is solubilized in THF at a concentration of 1 g / L. A volume of 100 pL is injected through a set of 3 size exclusion chromatography columns of the A GILENT brand (MIXED B LS). The columns are thermostated in an oven at 35°C. The stationary phase of the columns is based on a polystyrene divinylbenzene gel with controlled porosity. The polymer chains are separated according to the hydrodynamic volume they occupy when they are solubilized in the solvent. The larger the volume they occupy, the less accessible the pores of the columns are and the shorter their elution time. Detection is ensured by a refractometer (RI) thermostated at 35°C. Each elution volume is associated with a mass via Moore calibration (certified standard passage: standard polystyrenes from Polymer Standard Service (Mainz).The WATERS: EMPOWER software is used for data acquisition and analysis. It is then possible to determine the number-average molar masses (Mn), the mass-average molar masses (Mw) as well as the dispersity (D = Mw / Mn).

[0151] 1.4 Dynamic Properties

[0152] The dynamic properties are measured on a viscoanalyzer (Metravib VA4000), according to ASTM D 5992-96. The response of a sample of the vulcanized elastomeric composition (cylindrical specimens of 4 mm thickness and 400 mm) is recorded. 2 section), subjected to sinusoidal stress in alternating simple shear, at a frequency of 10 Hz, at a temperature of 60°C.

[0153] For the measurements of dynamic complex shear modulus (G*) and the loss factor tan(delta), a strain amplitude sweep is carried out from 0.1% to 100% peak-peak (forward cycle), then from 100% to 0.1% peak-peak (return cycle). For the return cycle, the maximum value of tan(delta) observed, noted tan(delta)max, is indicated; as well as the modulus G* at 50% strain noted G*50%. The tan(delta)max value is representative of the hysteresis of the material and in this case of the rolling resistance: the lower the value of tan(delta)max, the better the rolling resistance. The values ​​of G*25% measured at 60°C are representative of the rigidity, i.e. the resistance to deformation: the higher the value of G*25% at 60°C, the greater the rigidity of the material, and therefore the better the resistance to wear.

[0154] All values ​​are given in base 100 relative to a given control.

[0155] 1.5 Tensile Tests

[0156] Tensile tests are used to determine yield stresses and breaking properties. Unless otherwise stated, they are carried out in accordance with French standard NF T 46-002 (1988).

[0157] Processing the tensile records allows the modulus curve to be plotted as a function of elongation. The modulus used here is the nominal (or apparent) secant modulus measured at first elongation, calculated by referring to the initial section of the specimen. The nominal secant modulus (or apparent stress, in MPa) at 300% elongation, denoted MSA300, is measured at first elongation.

[0158] The breaking stresses (in MPa) and the elongations at break (in %) are measured at 60°C ± 2°C according to the French standard NF T 46-002 (1988).

[0159] All values ​​are given in base 100 relative to a given control. A value greater than 100 indicates a value greater than that of the control.

[0160] Synthesis of highly saturated diene elastomer

[0161] The copolymer of ethylene and 1,3-butadiene, elastomer E1, is synthesized according to the procedure described below.

[0162] All reagents are obtained commercially except for the metallocene which can be prepared according to the procedure described in WO 2007054224. Butyloctylmagnesium BOMAG (20% in heptane, G = 0.88 mol.L' 1 ) comes from Chemtura and is transferred and stored in a Schlenk tube under an inert atmosphere. The ethylene, N35 grade, comes from Air Liquide and is used without prior purification.

[0163] The polymerization of ethylene and 1,3-butadiene is carried out according to a continuous process in solution in methylcyclohexane at 80°C under 10 bar in the presence of a catalytic system (195 pmoles Nd per 100 g of monomers), the mass concentration of monomer feed in the reactor being 7%, the mass ratio 1,3-butadiene / ethylene being 0.79, the molar ratio active Mg / Nd being 2.7. The additional Mg to reach a ratio of 2.7 is provided by an addition of BOMAG in the polymerization medium.

[0164] At the desired conversion (83%, 120 minutes) to reach an Mn of approximately 160,000 g / mol, the polymerization is stopped at the line outlet using a solution of antioxidants in methylcyclohexane (0.8 pce of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 0.7 pce of 2,2'-methylene-bis(4-methyl-6-tertbutylphenol, pce: part by weight per hundred parts of elastomer). The copolymer is recovered by a steam distillation process called "stripping" well known to those skilled in the art, then dried on a worm machine equipped with a single screw.

[0165] The copolymer contains 69% ethylene unit, 23% butadiene unit (1,2 unit and 1,4 unit which is more than 80% in the form of 1,4-trans) and 8% cyclic unit (1,2-cyclohexane unit). Its transition temperature is -43°C (AT of 5°C, the AT being the temperature difference between the beginning of the glass transition and its end), its Mn of 157700 g / mol, its ML (1 +4) at 100°C of 69.

[0166] The catalytic system is a preformed catalytic system. It is prepared in methylcyclohexane from a metallocene, [Me2Si(Flu)2Nd(p-BH4)2Li(THF)] at 0.0065 mol / L, a co-catalyst, butyloctylmagnesium (BOMAG) whose BOMAG / Nd molar ratio is equal to 2.2, and a preformed monomer, 1,3-butadiene whose 1,3-butadiene / Nd molar ratio is equal to 90. The medium is heated to 80°C for a period of 5 hours. It is prepared according to a preparation method in accordance with paragraph 11.1 of patent application WO 2017093654 A1.

[0167] Preparation of the compositions

[0168] It is introduced into an internal mixer of volume: 3300 cm 3(final filling rate: approximately 70% by volume), whose initial tank temperature is approximately 50°C, successively the highly saturated diene elastomer, the reinforcing filler(s), where appropriate the hydrocarbon plasticizing resin, the secondary accelerators as well as the various other ingredients with the exception of the sulfur and the primary accelerator. Thermomechanical work is then carried out (non-productive phase) in one step, which lasts a total of approximately 3 to 4 minutes, until a maximum "fall" temperature of 160°C is reached. The mixture thus obtained is recovered, cooled and then the sulfur and the primary accelerator are incorporated on an external mixer (roll mixer) at 30°C, mixing everything (productive phase) for 10 minutes.

[0169] The crosslinking of the composition was carried out at a temperature of 140°C, under pressure, in a manner known to those skilled in the art.

[0170] The details of the formulations of the compositions are shown in Table 1.

[0171] The formulations of the prepared compositions are described in Table 1 (components and content - unless otherwise indicated, the contents are expressed in pce).

[0172] The as-prepared properties of the compositions are also shown in Table 1. Table 1: Formulation of the different compositions and properties in the cooked state

[0173] (1) Ethylene Butadiene copolymer containing 69% ethylene unit, 23% butadiene unit (1,2 unit and 1,4 unit which is more than 80% in the form of 1,4-trans) and 8% cyclic unit (1,2-cyclohexane unit). Its transition temperature is -43°C (AT of 5°C, the AT being the temperature difference between the beginning of the glass transition and its end), its Mn of 157700 g / mol, its Mooney viscosity ML (1+4) at 100°C of 69;

[0174] (3) Conventional carbon black of grade N234 according to standard D1765 - whose ash content is less than 0.7% by weight relative to the total weight of the carbon black, the sulfur content is less than 1.2% by weight relative to the total weight of the carbon black, the zinc is in the state of impurity (of the order of ppm);

[0175] (4) Pyrolysis carbon black “P550” from Scandinavian Enviro Systems, with an ash content of 18.5% by weight relative to the total weight of the pyrolysis carbon black, a sulfur content of 3% by weight relative to the total weight of the pyrolysis carbon black, and a zinc content of 4.5% by weight relative to the total weight of the pyrolysis carbon black.

[0176] (4) 2,2,2-trimethyl-l,2-dihydroquinoline from Flexsys

[0177] (5) N-cyclohexyl-2-benzothiazyl-sulfenamide from Flexsys

[0178] (6) tetrabenzylthiuram disulfide from Flexsys (0.30 pce) and diphenylguanidine from Flexsys (0.50 pce)

[0179] The tests highlight an improvement in the stiffness / hysteresis compromise without any significant penalty in the reinforcement for the compositions in accordance with the invention (C1, C2 and C3) compared to the composition not in accordance with the invention (TO).

[0180] From Table 1, it is noted that an increase in the pyrolysis carbon black content in a composition comprising an EBR elastomer (C1, C2 and C3) makes it possible to maintain a favorable stiffness / hysteresis compromise without significant penalty to the reinforcement (MSA300).

[0181] Surprisingly, the compositions in accordance with the invention C1, C2, C3 also have better elongation at break properties compared to the compositions not in accordance with the invention.

Claims

CLAIMS 1. Elastomeric composition based on: - at least one highly saturated diene elastomer, the highly saturated diene elastomer being a copolymer of ethylene and a 1,3-diene containing ethylene units which represent at least 50 mol% of the monomer units of the copolymer; - a reinforcing filler comprising at least one pyrolysis carbon black; and - a crosslinking system.

2. Elastomeric composition according to claim 1, in which the highly saturated diene elastomer comprises at least 60 mol% of ethylene unit, preferably at least 65 mol% of ethylene unit.

3. Elastomeric composition according to claim 1 or 2, in which the highly saturated diene elastomer contains units of formula (I) or units of formula (II) •CH CH(CH«CHi)- (tl) 4. Elastomeric composition according to claim 3, in which the highly saturated diene elastomer comprises units of formula (I) in a molar ratio greater than 0 and less than 15%.

5. Elastomeric composition according to any one of the preceding claims, in which the highly saturated diene elastomer is a copolymer of ethylene and 1,3-butadiene.

6. Elastomeric composition according to any one of the preceding claims, in which the pyrolysis carbon black has an ash content ranging from 5% to 30% by weight, preferably from 8% to 25% by weight, relative to the total weight of the pyrolysis carbon black.

7. Elastomeric composition according to any one of the preceding claims, in which the pyrolysis carbon black has a sulfur content greater than 2% by weight, preferably ranging from 2.5% to 5% by weight, relative to the total weight of the pyrolysis carbon black.

8. Elastomeric composition according to any one of the preceding claims, in which the level of reinforcing filler is within a range from 25 to 85 phr, preferably from 35 to 75 phr.

9. Elastomeric composition according to any one of the preceding claims, in which the pyrolysis carbon black represents more than 30% by weight, more preferably represents more than 50% by weight, more preferably still represents more than 70% by weight, even more preferably still represents more than 90% by weight of the total weight of the reinforcing filler.

10. Elastomeric composition according to any one of the preceding claims, in which the reinforcing filler further comprises at least one second reinforcing filler different from the pyrolysis carbon black, this second reinforcing filler being chosen from the group consisting of virgin carbon blacks, aluminas and silicas.

11. Elastomeric composition according to any one of the preceding claims, in which the level of highly saturated diene elastomer is at least 50 pce.

12. Elastomeric composition according to any one of the preceding claims, in which the level of highly saturated diene elastomer varies in a range from 50 to 100 phr, more preferably from 70 to 100 phr, preferably from 80 to 100 phr.

13. A rubber article comprising at least one elastomeric composition according to any one of claims 1 to 12, the article preferably being selected from the group consisting of hoses, pipes, seals, O-rings, transmission belts, engine mounts, insulators for electric cables, shoe soles, semi-finished articles for pneumatic tires, semi-finished articles for non-pneumatic tires, non-pneumatic tires and pneumatic tires.

14. Rubber article according to claim 13, characterized in that it is a semi-finished product for pneumatic tires, preferably in that it is a tread.

15. Rubber article according to claim 13, said article being a pneumatic or non-pneumatic tire whose tread is made in whole or in part of at least one elastomeric composition according to any one of claims 1 to 12.

Images