Elastomeric composition comprising pyrolytic carbon black

Abstract

The invention relates to an elastomer composition based on:-at least one highly saturated diene elastomer, which is a copolymer of ethylene and 1, 3-diene, in which ethylene units comprise at least 50 mol% of copolymer monomer units; -a reinforcing filler comprising at least one pyrolytic carbon black; and-a crosslinking system.

Description

Field of the Invention

[0001] The present invention relates to the field of reinforced elastomeric compositions, which compositions are in particular intended for the manufacture of rubber articles, such as semi-finished products for pneumatic or non-pneumatic tires, in particular for vehicles carrying heavy loads. Background of the Invention

[0002] Ideally, the elastomeric composition constituting the tread of a pneumatic or non-pneumatic tire must meet a number of technical requirements, which are often contradictory, including improving wear resistance while reducing the rolling resistance of the tire.

[0003] To increase the stiffness of the elastomeric composition, it is known, for example, to increase the content of reinforcing filler. However, the drawback of this solution is that it increases the hysteresis of the elastomeric composition.

[0004] Furthermore, in recent years, limiting the environmental impact of tire manufacturing and use has become a major challenge for manufacturers in the industry.

[0005] There is an increasing amount of research and development activity on producing tires based on recycled materials. For example, it has been proposed to use pyrolytic carbon black to completely or partially replace the conventional tire-grade carbon black used as a reinforcing filler in the elastomeric composition constituting a tire (in particular the tread). While this solution can improve hysteresis (rolling resistance), it comes at the cost of a reduction in stiffness, which results in a decrease in the wear resistance of the tire.

[0006] The loss of stiffness observed when using pyrolytic carbon black can in particular be compensated for by increasing the content of reinforcing filler in the elastomeric composition. However, this increase in the content of reinforcing filler leads to an increase in the hysteresis of the composition, thus risking adversely affecting the rolling resistance performance, especially for the tread of a pneumatic or non-pneumatic tire.

[0007] Therefore, there is still a need to provide elastomeric compositions that reduce the environmental impact by introducing recycled materials and maintain other properties while achieving a stiffness / hysteresis balance, which compositions can most particularly be used to form all or part of the tread of a pneumatic or non-pneumatic tire. Summary of the Invention

[0008] The present invention relates to an elastomeric composition based on:

[0009] - at least one highly saturated diene elastomer, which is a copolymer of ethylene and a 1,3-diene, wherein the ethylene units represent at least 50 mol% of the copolymer monomer units;

[0010] - a reinforcing filler, which reinforcing filler comprises at least one pyrolytic carbon black; and

[0011] - a crosslinking system.

[0012] The present invention also relates to a rubber article comprising at least one such elastomeric composition, said article preferably being selected from hoses, tubes, gaskets, O-rings, conveyor belts, engine mounts, cable insulators, shoe soles, semi-finished products for pneumatic tires, semi-finished products for non-pneumatic tires, non-pneumatic tires and pneumatic tires.

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

[0014] Definitions

[0015] The expression "the composition is based on" is to be understood as meaning that the composition comprises a mixture of the various components used and / or in-situ reaction products, some of these components being capable of and / or intended to react at least in part with one another during the course of the various stages of manufacture of the composition; thus the composition may be in a fully crosslinked or partially crosslinked state or in a non-crosslinked state.

[0016] The expression "parts by weight per 100 parts by weight of elastomer" (or phr) is to be understood as meaning parts by mass per 100 parts by mass of elastomer or rubber, the two terms being synonymous.

[0017] In the present text, unless otherwise expressly stated, all percentages (%) shown are percentages by mass (%).

[0018] Furthermore, any numerical interval represented by the expression "between a and b" represents a numerical range extending from greater than a to less than b (i.e. excluding the end values a and b), while any numerical interval represented by the expression "from a to b" means a numerical range extending from a up to b (i.e. including the exact end values a and b).

[0019] The compounds mentioned in the present specification may be compounds of fossil origin or may be bio-based compounds. In the latter case, they may be partly or wholly derived from biomass, or obtained from renewable raw materials derived from biomass. This relates in particular to polymers, plasticizers, fillers, etc.

[0020] The term "tires intended to equip vehicles carrying heavy loads" is generally understood to mean any tires for heavy goods vehicles, vans, metros, buses, civil engineering vehicles, agricultural vehicles, aircraft and other handling vehicles.

[0021] The term "elastomeric matrix" or "matrix of the elastomer" means all the elastomers present in the elastomeric composition.

[0022] Within the meaning of the present invention, the term "major" means that the compound is major among compounds of the same type in the composition, that is, the compound is the one with the largest amount by mass among compounds of the same type. In other words, the mass of the compound accounts for at least 51% of the total mass of compounds of the same type in the composition. For example, in a system containing only one elastomer, the elastomer is major within the meaning of the present invention, while in a system containing two elastomers, the major elastomer accounts for more than half of the total elastomer mass, in other words, the mass of the elastomer accounts for at least 51% of the total elastomer mass. Similarly, the "major" filler is the filler with the largest mass among the fillers in the composition. In other words, the mass of the filler accounts for at least 51% of the total filler mass in the composition.

[0023] All values of the glass transition temperature "Tg" were measured in a known manner by DSC (differential scanning calorimetry) according to standard ASTM D3418 (2008).

[0024] Unless otherwise specified, the content of monomer units or repeating subunit units in highly saturated diene elastomers is given as a molar percentage based on all monomer units of the elastomer. The term "all monomer units of the elastomer" refers to all the constituent repeating units of the elastomer generated by inserting monomers into the elastomer chain through polymerization. Detailed Description of the Invention

[0026] Surprisingly, the inventors have found that a specific combination of at least one highly saturated diene elastomer as described below, one reinforcing filler as described below, and a crosslinking system can result in an elastomer composition that meets the requirements.

[0027] Specifically, the elastomer composition can be used for pneumatic or non-pneumatic tires, especially for the treads of pneumatic or non-pneumatic tires used to equip vehicles carrying heavy loads. The proposed solution can reduce the environmental impact of tires by introducing recycled materials and can achieve a good stiffness / hysteresis (abrasion resistance / rolling resistance) balance.

[0028] Accordingly, the present invention relates to an elastomer composition based on:

[0029] - at least one highly saturated diene elastomer, which is a copolymer of ethylene and 1,3-diene, wherein the ethylene units account for at least 50 mol% of the copolymer monomer units;

[0030] - a reinforcing filler, which contains at least one pyrolytic carbon black; and

[0031] - a crosslinking system.

[0032] The invention also relates to a rubber article comprising at least one such elastomeric composition, said article preferably being selected from hoses, tubes, gaskets, O-rings, conveyor belts, engine mounts, cable insulators, shoe soles, semi-finished products for pneumatic tires, semi-finished products for non-pneumatic tires, non-pneumatic tires and pneumatic tires.

[0033] Other aspects of the invention are as described hereinafter and in the claims.

[0034] Highly saturated diene elastomers

[0035] The elastomeric composition used in the context of the present invention comprises at least one highly saturated diene elastomer, preferably random, (i.e. one or more highly saturated diene elastomers), said highly saturated diene elastomer being a copolymer of 1,3-diene units and ethylene units, wherein the ethylene units represent at least 50 mol% of the monomer units of the copolymer.

[0036] In the remainder of the present specification, the expression "highly saturated diene elastomer is a copolymer of 1,3-diene units and ethylene units, wherein the ethylene units represent at least 50 mol% of the monomer units of the copolymer".

[0037] In a known manner, the expression "ethylene unit" refers to the -(CH2-CH2)-subunit resulting from the insertion of ethylene into the elastomer chain. The highly saturated diene elastomer is rich in ethylene units since the ethylene units represent at least 50 mol% of all the monomer units of the elastomer.

[0038] Unless otherwise indicated, the content of the units resulting from the insertion of the monomers into the copolymer (such as the copolymer used in the present invention) is expressed as a molar percentage relative to all the monomer units of the copolymer.

[0039] Preferably, the highly saturated diene elastomer is a random copolymer.

[0040] 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. Still more preferably, the ethylene units represent at least 65 mol% of all the monomer units of the highly saturated diene elastomer.

[0041] Preferably, the ethylene units in the highly saturated diene elastomer account for at most 90 mol% of all the monomer units of the highly saturated diene elastomer. More preferably, the ethylene units account for at most 85 mol% of all the monomer units of the highly saturated diene elastomer. Still more preferably, the ethylene units account for at most 80 mol% of all the monomer units of the highly saturated diene elastomer.

[0042] According to an advantageous embodiment, the highly saturated diene elastomer comprises from 55 mol% to 90 mol% of ethylene units, in particular from 55 mol% to 85 mol% of ethylene units, the mole percentage being calculated based on all the monomer units of the highly saturated diene elastomer. More advantageously, the highly saturated diene elastomer comprises from 55 mol% to 80 mol% of ethylene units, the mole percentage being calculated based on all the monomer units of the highly saturated diene elastomer.

[0043] According to another advantageous embodiment, the highly saturated diene elastomer comprises from 60 mol% to 90 mol% of ethylene units, in particular from 60 mol% to 85 mol% of ethylene units, the mole percentage being calculated based on all the monomer units of the highly saturated diene elastomer. More advantageously, the highly saturated diene elastomer comprises from 60 mol% to 80 mol% of ethylene units, the mole percentage being calculated based on all the monomer units of the highly saturated diene elastomer.

[0044] According to another advantageous embodiment, the highly saturated diene elastomer comprises from 65 mol% to 90 mol% of ethylene units, in particular from 65 mol% to 85 mol% of ethylene units, the mole percentage being calculated based on all the monomer units of the highly saturated diene elastomer.

[0045] More advantageously, the highly saturated diene elastomer comprises from 65 mol% to 80 mol% of ethylene units, the mole percentage being calculated based on all the monomer units of the highly saturated diene elastomer.

[0046] Since the highly saturated diene elastomer is a copolymer of ethylene and 1,3-diene, it also contains 1,3-diene units resulting from the polymerization of 1,3-diene. In a known manner, the expression "1,3-diene unit" means, for example, in the case of isoprene, the units resulting from the insertion of 1,3-diene via 1,4 addition, 1,2 addition or 3,4 addition.

[0047] 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 preferably a random copolymer of ethylene and 1,3-butadiene.

[0048] The highly saturated diene elastomer preferably contains units of formula (I) and / or units of formula (II):

[0049]

[0050] -CH2-CH(CH=CH2)- (II)

[0051] For example, a copolymer of ethylene and a 1,3-diene may not contain units of formula (I). In this case, it preferably contains units of formula (II).

[0052] The saturated six-membered ring sub-unit of formula (I) present as a monomer unit in the copolymer, i.e., the 1,2-cyclohexanediyl sub-unit, can be produced by a very specific series of insertions of ethylene and 1,3-butadiene in the polymer chain during the growth of the polymer chain. When the highly saturated diene elastomer contains 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 o and p of the units of formula (I) and the units of formula (II) in the copolymer preferably satisfy the following formula 1 or formula 2 respectively, where o and p are calculated based on all the monomer units of the highly saturated diene elastomer:

[0053] 0 < o + p ≤ 30 (Formula 1)

[0054] 0 < o + p < 25 (Formula 2).

[0055] Preferably, the highly saturated diene elastomer contains units of formula (I) in a molar content greater than 0 mol% and less than 15 mol%, more preferably less than 10 mol%, based on all the monomer units of the highly saturated diene elastomer.

[0056] According to a particularly preferred embodiment, the highly saturated diene elastomer contains 1,4 units in a trans configuration (1,4-trans units). When the diene elastomer contains 1,4-trans units, the 1,4-trans units account for 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.

[0057] The highly saturated diene elastomer for the purposes of the present invention may consist of a mixture of highly saturated diene elastomers that are different from each other in microstructure or macrostructure.

[0058] Highly saturated diene elastomers can be obtained according to various synthesis methods known to those skilled in the art, in particular based on the target microstructure of the highly saturated diene elastomers. Generally, it can be prepared by the following methods: in particular, in the presence of a catalytic system containing a metallocene complex, at least 1,3-diene (preferably 1,3-butadiene) is copolymerized with ethylene according to known synthesis methods. In this regard, catalytic systems based on metallocene complexes can be mentioned, and these catalytic systems are described in the documents EP 1 092 731, WO 2004 / 035639, WO 2007 / 054223 and WO 2007 / 054224 under the name of the present applicant. Highly saturated diene elastomers (including when they are random) can also be prepared by methods using pre-formed type catalytic systems (such as those described in the documents WO 2017 / 093654 A1, WO 2018 / 020122 A1 and WO 2018 / 020123A1). Advantageously, the highly saturated diene elastomers are random and are preferably prepared according to semi-continuous or continuous processes such as those described in the documents WO 2017 / 103543 A1, WO 2017 / 13544A1, WO 2018 / 193193 and WO 2018 / 193194.

[0059] Preferably, the content of the highly saturated diene elastomer in the elastomer composition used in the context of the present invention is at least 50 parts by weight per 100 parts of elastomer of the elastomer composition (phr).

[0060] Preferably, the content of the highly saturated diene elastomer in the elastomer composition used in the context of the present invention varies in the range of 70 phr to 100 phr or 80 phr to 100 phr. More preferably, it varies in the range of 90 phr to 100 phr.

[0061] When the elastomer composition consists only of a highly saturated diene elastomer (100 phr), it contains at least one other diene elastomer. The proportion of the presence of this other elastomer is at most 50 phr (parts by weight per 100 parts of total elastomer), preferably at most 20 phr or at most 10 phr.

[0062] This other diene elastomer can be any homopolymer of a conjugated or non-conjugated diene monomer having 4 to 18 carbon atoms; or any copolymer of a conjugated or non-conjugated diene having 4 to 18 carbon atoms and at least one other monomer.

[0063] The other monomers can be olefins other than ethylene, or conjugated or non-conjugated dienes.

[0064] Suitable conjugated dienes include conjugated dienes having 4 to 12 carbon atoms, especially 1,3-dienes. More specifically, particularly suitable conjugated dienes include: 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C1-C5 alkyl)-1,3-butadiene, such as 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, aryl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene.

[0065] Suitable olefins include vinyl aromatic compounds having 8 to 20 carbon atoms and aliphatic α-monoolefins having 3 to 12 carbon atoms. Suitable vinyl aromatic compounds include, for example: styrene, (o-, m- or p-)methylstyrene, the commercial mixture "vinyltoluene", p-(tert-butyl)styrene, methoxystyrene, chlorostyrene, vinylmesitylene, divinylbenzene or vinylnaphthalene.

[0066] Suitable aliphatic α-monoolefins specifically include acyclic aliphatic α-monoolefins having 3 to 18 carbon atoms.

[0067] The other diene elastomer can have any microstructure. It can be a block, random, sequential or microsequential elastomer and can be prepared in emulsion or solution. It can be coupled and / or star-branched or functionalized with a coupling and / or star-branching agent or a functionalizing agent.

[0068] Preferably, the other diene elastomer used in the present invention is selected from highly unsaturated diene elastomers, including polybutadiene (BR), synthetic polyisoprene (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers. Such copolymers are more preferably selected from butadiene / styrene copolymers (SBR), isoprene / butadiene copolymers (BIR), isoprene / styrene copolymers (SIR) and isoprene / butadiene / styrene copolymers (SBIR).

[0069] It should be understood that the other diene elastomer can be formed from a mixture of diene elastomers that are different from each other in terms of their microstructure, their macrostructure or the presence of functionality, the nature of said functionality or the position of said functionality on the elastomer chain.

[0070] Reinforcing fillers

[0071] The elastomer composition used in the context of the present invention contains a reinforcing filler, said reinforcing filler containing at least one pyrolytic carbon black. In addition to the pyrolytic carbon black, the reinforcing filler can also contain one or more other reinforcing fillers.

[0072] Advantageously, a specific combination of at least one of the highly saturated diene elastomers as described above with at least one of the pyrolytic carbon blacks as described below surprisingly enables an elastomeric composition to be obtained having a good stiffness / hysteresis (abrasion resistance / rolling resistance) balance.

[0073] The term "reinforcing filler" denotes any type of filler known to be capable of reinforcing rubber compositions which can be used in particular for the manufacture of tyres, such as organic fillers (such as virgin carbon black or pyrolytic carbon black) or inorganic fillers (such as silica or alumina).

[0074] Thus, in addition to the pyrolytic carbon black, the elastomeric composition may also comprise at least one second reinforcing filler different from the pyrolytic carbon black, selected from silica, alumina and virgin carbon black.

[0075] A person skilled in the art will know how to adjust the total content of the reinforcing fillers, including the pyrolytic carbon black, according to the intended use of the elastomeric composition.

[0076] In some embodiments, the content of the reinforcing filler in the elastomeric composition used in the context of the present invention is in the range from 25 to 85 phr, preferably in the range from 30 to 75 phr, or from 35 to 75 phr.

[0077] Preferably, the pyrolytic carbon black represents more than 30% by weight, more preferably more than 50% by weight, still more preferably more than 70% by weight, and even more preferably more than 90% by weight of the total weight of the reinforcing fillers.

[0078] Thus, preferably, the content of the reinforcing filler in the elastomeric composition used in the context of the present invention is in the range from 25 to 85 phr, wherein the carbon black represents more than 30% by weight, more preferably more than 50% by weight, still more preferably more than 70% by weight, and even more preferably more than 90% by weight of the total weight of the reinforcing fillers.

[0079] Thus, more preferably, the content of the reinforcing filler in the elastomeric composition used in the context of the present invention and comprising at least one pyrolytic carbon black is in the range from 30 to 75 phr, the carbon black representing more than 30% by weight, more preferably more than 50% by weight, still more preferably more than 70% by weight, and even more preferably more than 90% by weight of the total weight of the reinforcing fillers.

[0080] In some embodiments, the reinforcing filler is only the pyrolytic carbon black. In some embodiments, the elastomeric composition comprises 25 to 85 phr, preferably 30 to 75 phr, of a reinforcing filler which is the pyrolytic carbon black. Thus, it should be understood that in this specific embodiment, the elastomeric composition comprises the pyrolytic carbon black as the only reinforcing filler (the elastomeric composition thus does not contain any inorganic reinforcing filler or other organic reinforcing filler).

[0081] The reinforcing filler can be described as follows.

[0082] Pyrolytic carbon black

[0083] The elastomeric composition used in the context of the present invention comprises at least one pyrolytic carbon black as a reinforcing filler.

[0084] In the context of the present invention, the term "pyrolytic carbon black" refers to the carbon black produced by the pyrolysis process of a material (hereinafter referred to as the material to be pyrolyzed) comprising at least a carbon-based polymer and carbon black, for example in the case of recycling such a material. The physical state of the provided material to be pyrolyzed is not important, whether it is in powder, granule, strip or any other form, in a crosslinked or non-crosslinked state.

[0085] Preferably, the material to be pyrolyzed can be recovered from articles or from products (such as by-products or waste) generated during their manufacture / production; these articles can be selected from pneumatic tires, non-pneumatic tires, industrial conveyor belts, drive belts, rubber seals, rubber hoses, shoe soles and windshield wipers. More preferably, the pyrolytic carbon black used in the context of the present invention is the carbon black obtained from a pyrolysis process, wherein the material to be pyrolyzed is derived from articles selected from pneumatic tires and non-pneumatic tires.

[0086] In the context of the present invention, "pyrolysis" refers to any type of thermal decomposition under anaerobic conditions, wherein the raw material is the material to be pyrolyzed as defined above. Thus, pyrolytic carbon black differs from "industrial" and / or "ASTM grade" carbon black (also called virgin carbon black) in that the carbon-based raw material used for pyrolysis is a material comprising at least a carbon-based polymer and carbon black, rather than a material derived from petroleum fractions or from coal or from oils of natural origin.

[0087] Therefore, the pyrolytic carbon black that can be used in the context of the present invention differs from known carbon blacks (such as industrial grade and / or ASTM grade carbon blacks, especially "furnace" carbon black, hereinafter referred to as "virgin carbon black") in that it has a higher ash content.

[0088] Preferably, relative to the total weight of the pyrolytic carbon black, the pyrolytic carbon black that can be used in the context of the present invention has an ash content in the range of 5% to 30% by weight, more preferably 8% to 25% by weight, still more preferably 10% to 22% by weight.

[0089] Preferably, relative to the total weight of the pyrolytic carbon black, the pyrolytic carbon black that can be used in the context of the present invention has a sulfur content in the range of greater than 2% by weight, preferably 2.5% to 5% by weight.

[0090] Preferably, relative to the total weight of the pyrolytic carbon black, the pyrolytic carbon black usable in the context of the present invention has a zinc content of greater than or equal to 2% by weight, preferably 2.5% to 8% by weight.

[0091] Preferably, the pyrolytic carbon black usable in the context of the present invention has a specific surface area (STSA) measured according to standard ASTM D 6556-2021 in the range of 20 m 2 / g to 200 m 2 / g, more preferably in the range of 30 m 2 / g to 90 m 2 / g.

[0092] Preferably, the pyrolytic carbon black usable in the context of the present invention has a void volume measured according to standard ASTM 7854 (2018) at a pressure of 50 MPa in the range of 30 to 60 ml / 100 g, more preferably 35 to 55 ml / 100 g.

[0093] The ash content is determined by calcination in a platinum dish in a muffle furnace at 825 °C according to the following protocol. Before each series of measurements, a dish is pre-determined and its tare weight is weighed to within 0.1 mg, and the mass is designated as P0. A 5 g sample of pyrolytic carbon black (accurately weighed to within 0.1 mg) is placed in the dish; this mass is designated as P1. The dish and its contents are pre-calcined using a Bunsen burner until smoke appears and the product ignites. Once the product has finished burning, the dish and its contents are placed in a muffle furnace heated to 825 °C for 1 hour. After 1 hour, the dish is removed from the furnace and immediately placed in a desiccator at ambient temperature. When the dish and the ash have returned to ambient temperature, the dish is weighed again to obtain the mass P2. Finally, the ash content (% ash) can be obtained using the following formula:

[0094]

[0095] After the sample has been calcined, the ash is then absorbed into an acidic medium and determined by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometry) to obtain the zinc content in the pyrolytic carbon black. The ash is obtained by performing the above protocol. Approximately exactly 100 mg of ash (test sample) is taken and introduced into a PFA (Perfluoroalkoxy) tube on a HotBlock heating plate. Then 8 ml of 37% concentrated hydrochloric acid, 3 ml of 65% concentrated nitric acid, and 0.5 ml of 40% hydrofluoric acid are added.

[0096] Seal the tube with a stopper and heat it at 130 °C for 2 hours. After cooling, transfer the contents to a 100 mL PTFE (polytetrafluoroethylene) volumetric flask containing 2 g of boric acid (for neutralizing hydrofluoric acid) using ultrapure water. Add ultrapure water up to the calibration mark. Dilute the resulting solution 100-fold by placing 1 mL of the solution into a 100 mL PFTE flask 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. Then filter the diluted solution through a 0.45 μm GHP syringe filter and analyze it by inductively coupled plasma atomic emission spectrometry (ICP-AES). Before analyzing the diluted solution, use ICP-AES to analyze at least 5 standard samples at zinc concentrations of 0, 0.5, 1, 2, and 5 mg / L. These standard samples are prepared by diluting a commercial solution with a certified zinc concentration of 1 g / L in a 100 mL volumetric flask.

[0097] These volumetric flasks already 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 λZn = 202.613 nm). For each standard concentration (c), plot the intensity of the zinc signal IZn on a graph IZn = f(c), which corresponds to a calibration line (type y = ax + b). Then measure the sample solution (diluted solution) of unknown concentration under the same conditions as the standard samples. Use the previously obtained calibration line to relate the measured intensity to the concentration. Since the test sample and volume have been recorded beforehand, the ash concentration [c] in mass % is obtained directly by software.

[0098] The concentration [c] of zinc in the pyrolytic carbon black in mass % is obtained from the following formula 炭黑 :

[0099] [c] 炭黑 = [c] 灰分 * 100 * % ash

[0100] Determine the sulfur content in pyrolytic carbon black using a LECO furnace. The LECO sulfur analyzer is designed to specifically measure the sulfur content in organic and / or inorganic materials by combustion and non-dispersive infrared detection. Before measuring the sulfur content in a sample, clean the boat and calibrate the furnace. The boat of the LECO furnace has been previously cleaned: this involves analyzing an empty boat under the same conditions as the sample. The calibration curve is plotted using a commercial standard sample called "BBOT", which has a purity greater than 99.99% and guaranteed contents of carbon (C), hydrogen (H), nitrogen (N), oxygen (O), and sulfur (S). The contents are as follows: C%: 72.52; H%: 6.09; N%: 6.51; O%: 7.43 and S%: 7.44. Weigh approximately exactly 10 ± 3, 20 ± 3, and 40 ± 3 mg of BBOT and place it in the boat. Place the standard sample / boat assembly in the combustion furnace and adjust it to 1350 °C under pure oxygen. The combination of the furnace temperature and the analysis flow rate causes the sample to burn and release sulfur and / or carbon in the form of SO2(g). After 20 seconds, oxygen starts to flow through the lance to accelerate the combustion of refractory materials. Sulfur and / or carbon are entrained by the oxygen flow through the infrared detection chamber in the form of SO2(g).

[0101] The instrument software plots a straight line that relates the introduced standard mass to the response (area) observed on the detector. In this way, a calibration straight line is obtained. After carefully cleaning the sampling equipment, weigh approximately exactly 80 ± 5 mg of pyrolytic carbon black and place it in the boat of the LECO furnace. Use the calibration straight line to relate the observed area of the SO2 peak to the concentration. Then the instrument software calculates the mass % of sulfur in the sample using the mass of the sample placed in the boat.

[0102] For example, BlackBear sells pyrolytic carbon black with reference to "BBCT30" or Scandinavian Enviro Systems sells it with reference to "P550".

[0103] Virgin carbon black

[0104] The elastomeric composition used in the context of the present invention may additionally contain carbon black other than pyrolytic carbon black, which is also referred to as "virgin carbon black" because it is not made from a material that already contains carbon black. Virgin carbon black is made from materials derived from petroleum fractions or from coal or from oils of natural origin.

[0105] Suitable virgin carbon blacks include all carbon blacks, especially those commonly used in tires or their treads, especially industrial carbon blacks, and more specifically "furnace" carbon blacks.

[0106] Among the native carbon blacks, particular mention will be made of the reinforcing native carbon blacks of the 100, 200 and 300 series, or the carbon blacks of the 500, 600 or 700 series (ASTM D-1765-2017 grades), such as N115, N134, N234, N326, N330, N339, N347, N375, N550, N683 and N772 carbon blacks.

[0107] The native carbon black can be used in the separate state as it is commercially available, or in any other form, for example as a carrier for some of the rubber additives used. The native carbon black can, for example, already have been introduced in the form of a masterbatch into a diene elastomer, in particular an isoprene elastomer (see, for example, applications WO 97 / 36724-A2 or WO 99 / 16600-A1).

[0108] Reinforcing inorganic fillers

[0109] The elastomer composition used in the context of the present invention can comprise silica or alumina (i.e. one or more silicas or aluminas), which are reinforcing inorganic fillers.

[0110] The term "reinforcing inorganic filler" should be understood herein to mean any inorganic or mineral filler, regardless of its color and its origin (natural or synthetic), which, compared to carbon black, is also called a "white" filler, a "transparent" filler or even a "non-black" filler, and which is capable of reinforcing alone the elastomer composition intended for the manufacture of tires without means other than an intermediate coupling agent. In a known manner, some reinforcing inorganic fillers can be characterized in particular by the presence of hydroxyl (-OH) groups on their surface.

[0111] Mineral fillers of the siliceous type (preferably silica (SiO2)) or of the aluminous type (in particular alumina (Al2O3)) are particularly suitable as reinforcing inorganic fillers. The silica used can be any reinforcing silica known to those skilled in the art, in particular any precipitated silica or pyrogenic silica with a BET specific surface area and a CTAB specific surface area both less than 450 m 2 / g, preferably in the range of 30 to 400 m 2 / g, in particular 60 to 300 m 2 / g.

[0112] Any type of precipitated silica can be used, in particular highly dispersible precipitated silica (HDS, i.e. "highly dispersible silica"). These precipitated silicas (whether or not highly dispersible) are well known to those skilled in the art. Mention may be made, for example, of the silicas described in applications WO03 / 016215-A1 and WO03 / 016387-A1. Among the commercially available HDS silicas, those from Evonik can be used in particular 5000 GR and 7000 GR silica, or from Solvay 1085 GR, 1115 MP, 1165 MP, Premium 200 MP and HRS 1200 MP silica. As non-HDS silica, the following commercially available silicas can be used: from Evonik VN2 GR and VN3 GR silica, from Solvay 175 GR silica, or Hi-Sil EZ120G(-D), Hi-Sil EZ160G(-D), Hi-Sil EZ200G(-D), Hi-Sil 243LD, Hi-Sil 210 and Hi-Sil HDP 320G from PPG.

[0113] The BET specific surface area of the 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” (Volume 60, page 309, February 1938), more particularly in accordance with the French standard NF ISO 9277 of December 1996 (multi-point (5-point) volume method - gas: nitrogen - degassing: 1 hour at 160 °C – relative pressure p / po range: 0.05 to 0.17). The CTAB specific surface area of the silica is determined in accordance with the French standard NF T 45-007 (Method B) of November 1987.

[0114] As other examples of inorganic fillers that can be used in elastomeric compositions, mineral fillers of the aluminum type can also be mentioned, in particular alumina (Al2O3), aluminum oxides, aluminum hydroxides, aluminum silicates, titanium oxides, silicon carbides or silicon nitrides, all of the reinforcing types described, for example, in patent applications WO 99 / 28376-A2, WO 00 / 73372-A1, WO 02 / 053634-A1, WO 2004 / 003067-A1, WO 2004 / 056915-A2, US 6 610 261-B1 and US 6 747 087-B2. Alumina Baikalox A125 or CR125 can be particularly mentioned APA-100 RDX (Condéa), Aluminium Oxide C (Evonik) or AKP-G015 (Sumitomo Chemicals).

[0115] The physical state of the provided reinforcing inorganic filler is not important, whether it is in the form of powder, microbeads, granules or beads or any other suitable densified form. Of course, the term "reinforcing inorganic filler" is also understood to mean a mixture of different reinforcing inorganic fillers, in particular a mixture of silica as described above.

[0116] Those skilled in the art will understand that a reinforcing filler of another nature can be used to replace the above-mentioned reinforcing inorganic filler, provided that the reinforcing filler of another nature is covered by an inorganic layer (such as silica) or includes functional sites (in particular hydroxyl sites) on its surface that require the use of a coupling agent to establish a bond between the reinforcing filler and the diene elastomer.

[0117] In order to couple the reinforcing inorganic filler to the highly saturated diene elastomer, at least a bifunctional coupling agent (or binder) designed to provide a satisfactory chemical and / or physical connection between the inorganic filler (on the surface of its particles) and the diene elastomer can be used in a known manner. In particular, at least a bifunctional organosilane or polyorganosiloxane is used. The term "bifunctional" is understood to mean that the compound has 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 can contain a first functional group containing a silicon atom and a second functional group containing a sulfur atom, the first functional group being capable of interacting with the hydroxyl groups of the inorganic filler and the second functional group being capable of interacting with the highly saturated diene elastomer.

[0118] Preferably, the organosilane is selected from organosilane polysulfides (symmetric or asymmetric) such as bis(3-triethoxysilylpropyl)tetrasulfide abbreviated as TESPT sold by Evonik under the name Si69 or bis(triethoxysilylpropyl)disulfide abbreviated as TESPD sold by Evonik under the name Si75, polyorganosiloxanes, mercapto silanes, end-capped mercapto silanes, such as S-[3-(triethoxysilyl)propyl] thioctanoate sold by Momentive under the name NXT silane. More preferably, the organosilane is an organosilane polysulfide.

[0119] Those skilled in the art can find examples of coupling agents 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 6849754, WO 99 / 09036, WO 2006 / 023815, WO 2007 / 098080, WO 2010 / 072685, and WO 2008 / 055986.

[0120] The content of the coupling agent preferably accounts for 0.5% to 15% by weight of the reinforcing inorganic filler, more preferably 4% to 12% by weight of the reinforcing inorganic filler, and even more preferably 6% to 10% by weight. Generally, the content of the coupling agent is less than 20 phr, preferably in the range of 6 to 17 phr, and more preferably in the range of 8 to 15 phr. This content can be easily adjusted by those skilled in the art according to the content of the reinforcing inorganic filler used in the elastomeric composition.

[0121] In addition to the coupling agent, the elastomeric composition may further contain a coupling activator, a reagent for covering the inorganic filler, or more common processing aids. These processing aids can improve the processability of the composition in the unprocessed state in a known manner because they improve the dispersion of the filler in the rubber matrix and reduce the viscosity of the composition. These processing aids are, for example, hydrolyzable silanes such as alkylalkoxysilanes (especially alkyltriethoxysilanes), polyols, polyethers (such as polyethylene glycol), primary amines, secondary amines or tertiary amines (such as trialkanolamines), hydroxylated or hydrolyzable POS, such as α,ω-dihydroxypolyorganosiloxanes (especially α,ω-dihydroxypolydimethylsiloxane).

[0122] Other organic fillers

[0123] The elastomeric composition used in the context of the present invention may contain a reinforcing organic filler of the functionalized vinyl type, as described in applications WO 2006 / 069792-A1, WO 2006 / 069793-A1, WO 2008 / 003434-A1, and WO 2008 / 003435-A1.

[0124] Crosslinking systems

[0125] The elastomeric composition used in the context of the present invention contains a crosslinking system.

[0126] The crosslinking system can be any type of system known to those skilled in the art in the field of elastomeric compositions for tires. It can be particularly based on sulfur and / or peroxide and / or bismaleimide.

[0127] Preferably, the crosslinking system is based on sulfur; it is then referred to as a vulcanization system.

[0128] Sulfur can be provided in any form, in particular in the form of molecular sulfur or a sulfur donor.

[0129] The term "sulfur donor" should be understood to mean any compound that releases sulfur atoms, which may or may not be bound in the form of polysulfide chains and which are capable of inserting into the polysulfide chains formed during vulcanization and bridging the elastomer chains. The sulfur content in the elastomer composition is preferably less than 2 phr, preferably between 0.3 phr and 1.5 phr.

[0130] Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur can be used as a (primary or secondary) vulcanization accelerator, in particular thiazole accelerators and their derivatives, sulfenamide accelerators (as primary accelerators), or thiuram, dithiocarbamate, dithiophosphate, thiourea, and xanthate accelerators (as secondary accelerators). Guanidine should be understood to mean any compound containing the divalent group -HN-C(=NH)-NH-. Guanidine is preferably diphenylguanidine. The amount of vulcanization accelerator is preferably between 0.3 phr and 5 phr, more preferably between 0.5 phr and 2.5 phr.

[0131] As examples of primary accelerators, mention may particularly be made of sulfenamide compounds such as N-cyclohexyl-2-benzothiazole sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazole sulfenamide ("DCBS"), N-tert-butyl-2-benzothiazolyl sulfenamide ("TBBS"), and mixtures of these compounds. The primary accelerator is preferably a sulfenamide, more preferably N-cyclohexyl-2-benzothiazole sulfenamide.

[0132] As examples of secondary accelerators, mention may particularly be made of thiuram polysulfides, preferably thiuram disulfide, such as tetraethylthiuram disulfide, tetrabutylthiuram disulfide ("TBTD"), tetrabenzylthiuram disulfide ("TBZTD"), and mixtures of these compounds. The secondary accelerator is preferably thiuram disulfide, more preferably tetrabenzylthiuram disulfide.

[0133] The primary accelerator is preferably a sulfenamide. When the primary vulcanization accelerator is a sulfenamide, it is preferably N-cyclohexyl-2-benzothiazole sulfenamide.

[0134] The vulcanization accelerator is preferably a mixture of a primary accelerator and a secondary accelerator. "Primary accelerator" refers to a single primary accelerator or a mixture of multiple primary accelerators.

[0135] Similarly, the "secondary accelerator" refers to a single secondary accelerator or a mixture of multiple 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 is preferably N-cyclohexyl-2-benzothiazole sulfenamide, the thiuram disulfide is preferably tetrabenzyl thiuram disulfide, and the guanidine is preferably diphenyl guanidine.

[0136] In a known manner, the vulcanization system may also contain vulcanization activators, such as metal oxides (such as zinc oxide) or fatty acids (such as stearic acid).

[0137] Common additives and processing aids

[0138] The elastomeric composition used in the context of the present invention may also contain all or some of the common additives and processing aids known to those skilled in the art and commonly used in tire elastomeric compositions, such as plasticizers (such as plasticizing oils and / or plasticizing resins), non-reinforcing fillers, pigments, raw rubber accelerators (i.e., tackifiers), pro-oxidant metal salts, protectants (such as antiozonant waxes), chemical antiozonants, antioxidants, antifatigue agents, reinforcing resins (such as those described in application WO 02 / 10269).

[0139] Preferably, the content of the plasticizer in the elastomeric composition used in the context of the present invention is in the range of 0 phr to 20 phr, more preferably in the range of 0 phr to 10 phr.

[0140] Preparation of the composition

[0141] The elastomeric composition used in the context of the present invention is manufactured in two consecutive preparation stages known to those skilled in the art in a suitable mixer:

[0142] - The first stage of thermomechanical processing or kneading ("non-production" stage), which can be carried out in a single thermomechanical step. During this step, all necessary components, in particular the highly saturated diene elastomer as defined above, the reinforcing fillers including pyrolytic carbon black, and various other optional additives other than the crosslinking system, are introduced into a suitable mixer, such as a standard internal mixer (such as a "Banbury" type). The reinforcing fillers can be introduced into the highly saturated diene elastomer all at once or in batches while thermomechanically kneading. The non-production stage is carried out at a high temperature, with the maximum temperature range being 110°C to 200°C and the duration range generally being 2 to 10 minutes;

[0143] - The second stage of machining ("production" stage), which is carried out in an external mixer (such as a mill) after the mixture obtained during the non - production first stage is cooled to a lower temperature (usually below 120 °C, for example 40 °C to 100 °C). Then a cross - linking system is introduced, and then the combined mixture is mixed for several minutes, for example 5 to 15 minutes.

[0144] Subsequently, the final elastomeric composition thus obtained is calendered into a form such as a sheet or slab, especially for laboratory characterization, or extruded into the form of a rubber semi - finished (or shaped) element, which can be used as, for example, a tire tread, especially as a tread for a tire of a heavy - load vehicle (especially a heavy goods vehicle or a civil engineering vehicle).

[0145] The elastomeric composition can be in an unprocessed state (before cross - linking or vulcanization) or in a cured state (after cross - linking or vulcanization), or can be a semi - finished product that can be used in a tire.

[0146] The elastomeric composition can be cross - linked in a manner known to those skilled in the art, for example, at a temperature of 130 °C to 200 °C, preferably under pressure for a sufficient time, which can vary, for example, from 5 minutes to 90 minutes.

[0147] Rubber products

[0148] Another subject of the present invention relates to a rubber product comprising at least one elastomeric composition as defined above.

[0149] The rubber product can be any type of product, such as a hose, a pipe, a gasket, an O - ring, a conveyor belt, an engine mount, a cable insulator, a sole, a semi - finished product for a pneumatic tire, a semi - finished product for a non - pneumatic tire, a pneumatic tire or a non - pneumatic tire.

[0150] Preferably, the rubber product is selected from semi - finished products for pneumatic tires, semi - finished products for non - pneumatic tires, pneumatic tires and non - pneumatic tires.

[0151] The semi - finished product for a pneumatic tire or a non - pneumatic tire is a rubber product intended for the manufacture of a pneumatic tire or a non - pneumatic tire. This can be any type of rubber strip, such as especially a tread, a base layer, etc.

[0152] More preferably, the elastomeric composition as defined above used in the context of the present invention constitutes all or part of the semi - finished product.

[0153] Preferably, the semi - finished product for a pneumatic tire or a non - pneumatic tire is a tread.

[0154] In a known manner, the tread of a pneumatic or non-pneumatic tire includes a tread surface which is intended to come into contact with the ground when the pneumatic or non-pneumatic tire rolls. The tread is provided with a tread pattern which specifically includes tread pattern elements or basic blocks delimited by various grooves.

[0155] Advantageously, the elastomeric composition as defined above used in the context of the present invention is present in the tread of a pneumatic or non-pneumatic tire, preferably in the radially outer part of the tread which is intended to come into contact with the ground when the pneumatic or non-pneumatic tire rolls. Even more preferably, the elastomeric composition as defined above used in the context of the present invention constitutes all or part of the tread, particularly for a pneumatic or non-pneumatic tire.

[0156] The term "pneumatic tire" means a tire which is intended to form a cavity by engaging with a support element (such as a rim), and the cavity can be pressurized to a pressure higher than atmospheric pressure.

[0157] Conversely, a "non-pneumatic tire" is a tire which supports the vehicle load by means other than pressurized inflation gas. Thus, a non-pneumatic tire is an annular body made of at least one polymeric material, which is intended to perform the function of a tire but does not withstand inflation pressure. A non-pneumatic tire can be solid or hollow. A hollow non-pneumatic tire can contain air, but at atmospheric pressure, that is, it does not have the inflation stiffness provided by inflation gas at a pressure higher than atmospheric pressure. Non-pneumatic tires are described, for example, in documents WO 03 / 018332 and FR 2 898 077.

[0158] Pneumatic or non-pneumatic tires are particularly intended to equip all types of vehicles.

[0159] Preferably, the rubber article according to the present invention is a semi-finished product for a pneumatic tire, preferably a tread, such as a tread which is specifically wholly or partly made of at least one elastomeric composition as described above. Even more preferably, the above semi-finished product is a semi-finished product for industrial vehicles, such as heavy goods vehicles, vans, agricultural vehicles, buses, subways, civil engineering vehicles, aircraft and other handling vehicles.

[0160] Even more preferably, the rubber article according to the present invention is a pneumatic tire which comprises at least one elastomeric composition, particularly in its tread, and the elastomeric composition constitutes all or part of the tread. Even more preferably, the rubber article is a pneumatic tire for industrial vehicles (such as heavy goods vehicles, vans, agricultural vehicles, buses, subways, civil engineering vehicles, aircraft and other handling vehicles). The pneumatic tire can be manufactured by any method known to those skilled in the art.

[0161] Preferably, the rubber article is a pneumatic or non-pneumatic tire, and all or part of its tread is composed of at least one elastomeric composition according to the present invention. Detailed Description of the Invention

[0162] The following examples are given for illustrative purposes and should not be construed as limiting the present invention in any way.

[0163] Examples

[0164] Measurement Methods

[0165] 1.1 Determination of Elastomer Microstructure

[0166] The copolymer of ethylene and 1,3-butadiene was characterized by 1 H and 13 C NMR spectroscopy. NMR spectra were recorded on a Bruker Avance III 500 MHz spectrometer equipped with a BBI z-grad 5 mm "broadband" cryoprobe. 1 For the H NMR quantitative experiment, a simple 30° pulse sequence and a repetition time of 5 seconds between each acquisition were used. 64 to 256 accumulations were carried out. 13 For the C NMR quantitative experiment, a 30° single pulse sequence in the case of proton decoupling and a repetition time of 10 seconds between each acquisition were used. 1024 to 10240 accumulations were carried out. 1 H / 13 C two-dimensional experiments were used to determine the structure of the polymer. The determination of the microstructure of the copolymer was defined according to the paper by Llauro et al., Macromolecules 2001, 34, 6304 - 6311. NMR measurements were carried out at 25 °C. The copolymer was dissolved in a deuterated solvent (about 25 mg of elastomer in 1 ml), usually deuterated chloroform (CDCl3).

[0167] 1.2 Mooney Viscosity:

[0168] The Mooney viscosity was measured using an oscillating consistency meter as described in standard ASTM D1646 (1999). This measurement was carried out based on the following principle: The sample to be analyzed in the unprocessed state (i.e., before curing) was molded (formed) in a cylindrical chamber heated to a given temperature (100 °C). After preheating for 1 minute, the rotor rotated at 2 revolutions per minute within the test specimen, and the working torque required to maintain this motion was measured after 4 minutes of rotation. The Mooney viscosity (ML) is expressed in "Mooney units" (MU, 1 MU = 0.83 Newton·meter).

[0169] 1.3 Size Exclusion Chromatography (SEC / RI)

[0170] Size exclusion chromatography (SEC) can fractionate polymers in solution according to their hydrodynamic volume. As with all chromatography systems, this technique is based on the elution of a solute (polymer) through a chromatographic column containing a stationary phase. The system consists of the following in order: a solvent reservoir, a pump system, a syringe, a set of chromatographic columns, and a detector. The measurement system is equipped with a Waters Alliance e2695 module and a Waters fRI410 refractometer.

[0171] The mobile phase was eluted at a flow rate of 1 ml / min. The polymer was dissolved in THF at a concentration of 1 g / l. A volume of 100 μl was injected through a set of three size exclusion chromatographic columns (AGILENT (MIXED B LS) brand). The columns were placed in an oven maintained at a temperature of 35 °C. The stationary phase of the columns was based on a polystyrene / divinylbenzene gel with controllable porosity.

[0172] The separation of polymer chains is based on the hydrodynamic volume they occupy when dissolved in the solvent. The larger the volume occupied by the polymer chains, the fewer column pores they can enter, and the shorter their elution time. Detection was carried out by a refractometer (RI) maintained at a constant temperature of 35 °C. Each elution volume was correlated with mass by Moore calibration (calibration based on certified standards: polystyrene standards obtained from Polymer Standard Service (Mainz)). Data were acquired and analyzed using WATERS:EMPOWER software. From this, the number-average molar mass (Mn), weight-average molar mass (Mw), and dispersity could be determined.

[0173] 1.4 Kinetic properties

[0174] Kinetic properties were measured on a viscometer (Metravib VA4000) according to standard ASTM D 5992-96. The response of a sample of a vulcanized elastomeric composition (cylindrical specimen with a thickness of 4 mm and a cross-sectional area of 400 mm²) subjected to a simple alternating sinusoidal shear stress at a frequency of 10 Hz at a temperature of 60 °C was recorded.

[0175] For the measurement of the complex dynamic shear modulus (G*) and the loss factor tan(δ), the strain amplitude scan was carried out from 0.1% to 100% peak-to-peak (outward cycle), and then from 100% to 0.1% peak-to-peak (return cycle). For the return cycle, the maximum value of the observed tan(δ) (denoted as tan(δ)max) and the modulus G* at 50% strain (denoted as G*50%) were shown.

[0176] The value of tan(δ)max indicates the hysteresis of the material and also indicates the rolling resistance in this example: the smaller the value of tan(δ)max, the better the rolling resistance. The value of G*25% measured at 60 °C represents the stiffness, i.e., the resistance to deformation: the higher the value of G*25% at 60 °C, the greater the stiffness of the material and thus the better the wear resistance.

[0177] All values are given as a base 100 relative to a given control sample.

[0178] 1.5 Tensile tests

[0179] These tensile tests make it possible to determine the elastic stress and the fracture properties. Unless otherwise stated, these tests are carried out in accordance with the French standard NF T 46-002 (1988).

[0180] Processing the tensile records makes it possible to specifically plot the curve of the modulus as a function of elongation. The modulus used in this article is the nominal (or apparent) secant modulus, which is measured during the first elongation and calculated by reduction to the initial cross-section of the specimen. The nominal secant modulus (or apparent stress, in MPa) at 300% elongation, denoted as MSA300, is measured during the first elongation.

[0181] The breaking stress (in MPa) and the breaking elongation (in %) are both measured at 60 °C ± 2 °C in accordance with the French standard NF T 46-002 (1988).

[0182] All values are given as a base 100 relative to a given control sample.

[0183] Values greater than 100 indicate that the value is greater than that of the control sample.

[0184] Synthesis of highly saturated diene elastomers

[0185] A copolymer of ethylene and 1,3-butadiene, i.e., elastomer E1, is synthesized according to the following procedure.

[0186] All reagents are commercially available, except that the metallocene can be prepared according to the procedure described in document WO2007 / 054224.

[0187] Butyloctylmagnesium BOMAG (20% in heptane, C = 0.88 mol.l -1 ) is from Chemtura, which is transferred to a Schlenk tube and then stored in the Schlenk tube under an inert atmosphere. Grade N35 ethylene is from Air Liquide and can be used without prior purification.

[0188] Ethylene and 1,3-butadiene are polymerized in a methylcyclohexane solution at 80 °C and a pressure of 10 bar using a continuous process. In the presence of a catalytic system (195 μmol Nd per 100 g of monomers), the weight concentration of the monomers added to the reactor is 7%, the 1,3-butadiene / ethylene weight ratio is 0.79, and the active Mg / Nd molar ratio is 2.7. Supplementary Mg is provided by adding BOMAG to the polymerization medium to achieve a ratio of 2.7.

[0189] When the desired conversion (83%, 120 minutes) with an Mn of approximately 160,000 g / mol is reached, the polymerization is terminated at the pipeline outlet using a methylcyclohexane solution of antioxidants (0.8 phr of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 0.7 phr of 2,2'-methylenebis(4-methyl-6-tert-butylphenol)); phr = parts by weight / 100 parts of elastomer. The copolymer is recovered by a steam distillation process (referred to as "stripping") known to those skilled in the art and then dried on a worm machine equipped with a single screw.

[0190] The copolymer contains 69% ethylene units, 23% butadiene units (1,2 units and 1,4 units, with more than 80% in the 1,4-trans form), and 8% cyclic units (1,2-cyclohexane subunits). Its transition temperature is -43 °C (ΔT is 5 °C, where ΔT is the temperature difference between the start and end of the glass transition), its Mn is 157,700 g / mol, and its ML(1+4) at 100 °C is 69.

[0191] The catalytic system is a preformed catalytic system. It is prepared in methylcyclohexane from 0.0065 mol / L of metallocene [Me2Si(Flu)2Nd(μ-BH4)2Li(THF)], the cocatalyst butyloctylmagnesium (BOMAG) (the BOMAG / Nd molar ratio is equal to 2.2), and the preformed monomer 1,3-butadiene (the 1,3-butadiene / Nd molar ratio is equal to 90). The medium is heated to 80 °C for 5 hours. It is prepared according to the preparation method in paragraph II.1 of patent application WO 2017 / 093654 A1.

[0192] Preparation of the composition

[0193] A highly saturated diene elastomer, a reinforcing filler, an optional hydrocarbon-based plasticizing resin, a secondary accelerator, and various other components other than sulfur and the primary accelerator are introduced successively into an internal mixer with a volume of 3300 cm³ (final filling rate: approximately 70% by volume), and the initial container temperature of the internal mixer is approximately 50 °C. Then, thermomechanical processing (non-production stage) is carried out in one step, which lasts for a total of approximately 3 to 4 minutes until a maximum "discharge" temperature of 165 °C is reached. The mixture thus obtained is recovered, cooled, and then sulfur and the primary accelerator are introduced into an external mixer (open mill) at 30 °C, and all substances are mixed (production stage) for 10 minutes.

[0194] The composition is crosslinked under pressure at a temperature of 140 °C in a manner known to those skilled in the art.

[0195] Table 1 lists the formulation details of the composition.

[0196] The formulation of the prepared composition is shown in Table 1 (components and contents - unless otherwise specified, the contents are expressed in phr).

[0197] Table 1 also lists the properties of the prepared composition in the cured state.

[0198]

[0199]

[0200] Table 1: Formulations and Properties in the Cured State of Different Compositions

[0201] (1) Ethylene / butadiene copolymer, containing 69% ethylene units, 23% butadiene units (1,2 units and 1,4 units, where more than 80% are in the 1,4-trans form), and 8% cyclic units (1,2-cyclohexane subunits). Its transition temperature is -43 °C (ΔT is 5 °C, where ΔT is the temperature difference between the start and end of the glass transition), its Mn is 157,700 g / mol, and its Mooney viscosity ML(1+4) at 100 °C is 69.

[0202] (3) Conventional N234 grade carbon black conforming to ASTM D1765 standard, with an ash content of less than 0.7% by weight of the total weight of the carbon black, a sulfur content of less than 1.2% by weight of the total weight of the carbon black, and zinc as an impurity (in ppm level);

[0203] (4) Pyrolytic carbon black "P550" obtained from Scandinavian Enviro Systems, with an ash content of 18.5% by weight of the total weight of the pyrolytic carbon black, a sulfur content of 3% by weight of the total weight of the pyrolytic carbon black, and a zinc content of 4.5% by weight of the total weight of the pyrolytic carbon black;

[0204] (4) 2,2,2 - trimethyl - 1,2 - dihydroquinoline obtained from Flexsys;

[0205] (5) N - cyclohexyl - 2 - benzothiazole sulfenamide obtained from Flexsys;

[0206] (6) Tetrabenzylthiuram disulfide (0.30 phr) obtained from Flexsys and diphenylguanidine (0.50 phr) obtained from Flexsys.

[0207] Tests show that, compared with the compositions (T0) not according to the present invention, the stiffness / hysteresis balance of the compositions (C1, C2 and C3) according to the present invention is improved and does not significantly and adversely affect the strength.

[0208] According to Table 1, it was observed that an increase in the content of pyrolytic carbon black in the compositions containing the EBR elastomer (C1, C2 and C3) enables the favorable stiffness / hysteresis balance to be maintained and does not significantly and adversely affect the strength (MSA300).

[0209] Surprisingly, compared with the compositions not according to the present invention, the compositions C1, C2 and C3 according to the present invention also have better elongation - at - break properties.

Claims

1. An elastomeric composition, based on: - at least one highly saturated diene elastomer, which is a copolymer of ethylene and a 1,3-diene, wherein the ethylene units account for at least 50 mol% of the copolymer monomer units; - a reinforcing filler, which comprises at least one pyrolytic carbon black; and - a crosslinking system.

2. The elastomeric composition according to claim 1, wherein, The highly saturated diene elastomer comprises at least 60 mol% of ethylene units, preferably at least 65 mol% of ethylene units.

3. The elastomeric composition according to claim 1 or 2, wherein, The highly saturated diene elastomer comprises units of formula (I) or units of formula (II), 4. The elastomeric composition according to claim 3, wherein, The highly saturated diene elastomer comprises units of formula (I) in a molar content greater than 0 and less than 15%.

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

6. The elastomeric composition according to any one of the preceding claims, wherein, Relative to the total weight of the pyrolytic carbon black, the ash content of the pyrolytic carbon black ranges from 5 wt% to 30 wt%, preferably from 8 wt% to 25 wt%.

7. The elastomeric composition according to any one of the preceding claims, wherein, Relative to the total weight of the pyrolytic carbon black, the sulfur content of the pyrolytic carbon black is greater than 2 wt%, preferably from 2.5 wt% to 5 wt%.

8. The elastomeric composition according to any one of the preceding claims, wherein, The content of the reinforcing filler ranges from 25 phr to 85 phr, preferably from 35 phr to 75 phr.

9. The elastomeric composition according to any one of the preceding claims, wherein, The pyrolytic carbon black accounts for more than 30 wt% of the total weight of the reinforcing filler, more preferably more than 50 wt%, still more preferably more than 70 wt%, and even more preferably more than 90 wt%.

10. The elastomeric composition according to any one of the preceding claims, wherein, The reinforcing filler further comprises at least one second reinforcing filler other than the pyrolytic carbon black, and the second reinforcing filler is selected from virgin carbon black, alumina and silica.

11. The elastomeric composition according to any one of the preceding claims, wherein, The content of the highly saturated diene elastomer is at least 50 phr.

12. The elastomeric composition according to any one of the preceding claims, wherein, The content of the highly saturated diene elastomer varies in the range of 50 phr to 100 phr, more preferably in the range of 70 phr to 100 phr, and preferably in the range of 80 phr to 100 phr.

13. A rubber article, which comprises at least one elastomeric composition according to any one of claims 1 to 12, and the article is preferably selected from hoses, tubes, gaskets, O-rings, conveyor belts, engine mounts, cable insulators, shoe soles, semi-finished products for pneumatic tires, semi-finished products for non-pneumatic tires, non-pneumatic tires and pneumatic tires.

14. The rubber product according to claim 13, characterized in that, The rubber article is a semi-finished product for a pneumatic tire, and preferably the rubber article is a tread.

15. The rubber article according to claim 13, wherein the article is a pneumatic tire or a non-pneumatic tire, and all or part of the tread thereof is composed of at least one elastomeric composition according to any one of claims 1 to 12.

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