Elastomer compositions comprising at least one pyrolysis carbon black and carbon nanotubes

Abstract

The present invention relates to an elastomer composition based on: - a blend of elastomers comprising from 35 to 90 phr of natural rubber (NR) and / or of synthetic polyisoprenes (IR) and from 10 to 65 phr, preferably from 20 to 65 phr, of one or more diene elastomers selected from the group consisting of polybutadienes (BR), butadiene copolymers and isoprene copolymers; - reinforcing fillers comprising: - from 10 to 85 phr of pyrolysis carbon black, preferably from 10 to 45 phr of pyrolysis carbon black; and - from 1.0 to 10 phr of carbon nanotubes; - a crosslinking system.

Description

[0001] DESCRIPTION

[0002] Elastomeric compositions comprising at least one pyrolysis carbon black and carbon nanotubes

[0003] FIELD OF INVENTION

[0004] The present invention relates to the field of elastomeric compositions, particularly those intended for the manufacture of pneumatic or non-pneumatic bandages.

[0005] STATE OF THE ART

[0006] In recent years, limiting the environmental impact of tire manufacturing and use has become a major challenge for industry players. Research and development initiatives to produce tires with elastomeric compounds made from recycled or bio-based materials have proliferated. For example, it has been proposed to use pyrolysis carbon black as a total or partial substitute for conventional carbon black used as a reinforcing filler in tire elastomeric compounds; conventional carbon black being obtained from non-renewable raw materials of petroleum or fossil origin such as tars, oils, and / or gases.However, this partial or total substitution of conventional carbon blacks with pyrolysis carbon blacks comes with several drawbacks, including an increase in the Mooney viscosity of the elastomeric compositions. An increase in Mooney viscosity translates into a decrease in the industrial performance of the elastomeric compositions (calandrability and extrudability), in other words, a decrease in their processability. The formulation of elastomeric compositions based on recycled materials is therefore not trivial; the major difficulty lies in reconciling good processability (raw viscosity) with maintaining their technical performance, such as good durability (high stiffness when cured) and low hysteresis in the cured state (ensuring low rolling resistance).Thus, there remains a need to provide elastomeric compositions with a reduced environmental footprint, incorporating recycled materials and which satisfy a good compromise of rigidity / hysteresis / processability.

[0007] SUMMARY OF THE INVENTION

[0008] The present invention relates to an elastomeric composition based on: a mixture of elastomers comprising 35 to 90 parts per million of natural rubber (NR) or synthetic polyisoprenes (IR) or a mixture thereof, and 10 to 65 parts per million of one or more diene elastomers selected from the group consisting of polybutadienes (BR), butadiene copolymers, and isoprene copolymers; and reinforcing fillers comprising:

[0009] - 10 to 85 pieces of pyrolysis carbon black; and

[0010] - 1.0 to 10 pc of carbon nanotubes; of a crosslinking system.

[0011] The invention also relates to a rubber article comprising at least one elastomeric composition according to the invention.

[0012] Other aspects of the invention are as described below.

[0013] DEFINITIONS

[0014] 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 manufacturing the composition; the composition can thus be in a totally or partially crosslinked state or in a non-crosslinked state.

[0015] By the expression "part by weight per hundred parts by weight of elastomer" (or pce), we must understand the part, by mass per hundred parts by mass of elastomer or rubber, the two terms being synonymous.

[0016] In this document, unless expressly stated otherwise, all percentages (%) shown are percentages (%) by mass.

[0017] 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 (that is, bounds a and b excluded) while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​going from a to b (that is, including the strict bounds a and b).

[0018] The compounds mentioned in the description can be of fossil origin, derived from biomass. Obviously, the compounds mentioned can also come from the recycling of previously used materials; that is, they can be partially or totally derived from a recycling process, or even obtained from raw materials themselves derived from a recycling process. This includes, in particular, polymers, plasticizers, reinforcing fillers, etc.

[0019] By "elastomeric matrix" or "elastomeric matrix", we mean the entire set of elastomer(s) present in the elastomeric composition.

[0020] For the purposes of this invention, "majority" or "majority" means that the compound is the major component among the compounds of the same type in the composition; that is, it is the one that represents the largest quantity by mass among the compounds of the same type. In other words, the mass of this compound represents more than 50% of the total mass of the compounds of the same type in the composition, for example, at least 51%. By way of example, in a system comprising a single elastomer, this compound is the major component within the meaning of this invention; and in a system comprising two elastomers, the major elastomer represents more than half of the total mass of the elastomers; in other words, the mass of this elastomer represents more than 50%, for example, at least 51%, of the total mass of the elastomers. Similarly, a so-called major component is the one representing the largest mass among the components in the composition.In other words, the mass of this filler represents more than 50%, for example at least 51%, of the total mass of fillers in the composition.

[0021] All glass transition temperature values ​​“Tg” are measured in a known manner by Differential Scanning Calorimetry (DSC) according to ASTM D3418 (2008).

[0022] DETAILED DESCRIPTION OF THE INVENTION

[0023] Surprisingly, the inventors discovered that adding carbon nanotubes to an elastomeric composition primarily composed of pyrolysis carbon black as a reinforcing filler addresses the stated need. The proposed compositions reduce the environmental footprint of tires by incorporating recycled materials. They offer a good compromise between cured and uncured stiffness while providing low rolling resistance.

[0024] Thus, the present invention relates to an elastomeric composition based on: a mixture of elastomers comprising 35 to 90 parts per million, preferably 35 to 80 parts per million, of natural rubber (NR) or synthetic polyisoprenes (IR) or a mixture thereof, and 10 to 65 parts per million, preferably 20 to 65 parts per million, of one or more diene elastomers selected from the group consisting of polybutadienes (BR), butadiene copolymers, and isoprene copolymers; and reinforcing fillers comprising:

[0025] - 10 to 85 pieces of pyrolysis carbon black, preferably 10 to 45 pieces of pyrolysis carbon black; and

[0026] - 1.0 to 10 pc, preferably 1.3 to 7.5 pc or 1.5 to 6.5 pc, of carbon nanotubes; of a crosslinking system.

[0027] The various constituents of the elastomeric composition can be described below. Elastomer

[0028] The elastomeric composition of the present invention is based on a mixture of elastomers (or indistinctly rubber) comprising 35 to 90 parts, preferably 35 to 80 parts, of natural rubber (NR) or synthetic polyisoprenes (IR) or mixture thereof; and 10 to 65 parts, preferably 20 to 65 parts, of one or more diene elastomers selected from the group consisting of polybutadienes (BR), butadiene copolymers and isoprene copolymers.

[0029] In certain embodiments, the composition according to the invention comprises, as an elastomer, a mixture of natural rubber (NR) or synthetic polyisoprene (IR) or a mixture thereof, and at least one polybutadiene (BR). Preferably, the elastomer mixture consists of 35 to 90 parts per cent, preferably 35 to 80 or even 35 to 75 parts per cent, of natural rubber (NR) or synthetic polyisoprene (IR) or a mixture thereof, and 10 to 65 parts per cent, preferably 20 to 65 or even 25 to 65 parts per cent, of one or more polybutadienes (BR), in particular 40 to 60 parts per cent of natural rubber (NR) or synthetic polyisoprene (IR) or a mixture thereof, and 40 to 60 parts per cent of one or more polybutadienes (BR). In these embodiments, the reinforcing fillers comprise, preferably, 1.0 to 4.5 pc, preferably 1.3 to 3.5 pc or 1.5 to 3 pc, of carbon nanotubes, the amount of pyrolysis carbon black being as described above or below.

[0030] In some embodiments, the composition according to the invention comprises, as an elastomer, a mixture of elastomers comprising 35 to 90 parts per annum, preferably 35 to 80 parts per annum of natural rubber (NR) or synthetic polyisoprenes (IR) or mixture thereof, and 10 to 65 parts per annum, preferably 20 to 65 parts per annum, of one or more diene elastomers selected from the group consisting of butadiene copolymers and isoprene copolymers, preferably selected from butadiene copolymers, preferably butadiene-styrene copolymers (SBR).

[0031] In some embodiments, the composition according to the invention comprises, as an elastomer, a mixture of natural rubber (NR) or synthetic polyisoprene (IR) or a mixture thereof, and at least one or more butadiene-styrene (SBR) copolymers. Preferably, the elastomer mixture consists of 35 to 90 parts, preferably 35 to 80 parts or 35 to 80 parts of natural rubber (NR) or synthetic polyisoprene (IR) or a mixture thereof, and 10 to 65 parts, preferably 20 to 65 parts or 20 to 65 parts, of one or more butadiene-styrene (SBR) copolymers, in particular 55 to 80 parts of natural rubber (NR) or synthetic polyisoprene (IR) or a mixture thereof, and 20 to 45 parts of one or more parts of one or more butadiene-styrene (SBR) copolymers.

[0032] The composition of the present invention includes reinforcing fillers.

[0033] The term "reinforcing filler" refers to any type of filler known for its ability to reinforce an elastomeric composition usable in particular for the manufacture of tires, such as carbon black, pyrolysis carbon black, carbon nanotubes, siliceous or aluminous mineral fillers, etc.

[0034] The composition of the present invention comprises:

[0035] - 10 to 85 pieces, preferably 10 to 45 pieces, of pyrolysis carbon black; and

[0036] - 1.3 to 10 pc, preferably 1.3 to 7.5 pc or 1.5 to 6.5 pc, of carbon nanotubes.

[0037] In some embodiments, the composition of the present invention comprises at least 5 pieces of carbon nanotubes, preferably 5 to 9 pieces or 5 to 7.5 pieces or 5 to 6.5 pieces of carbon nanotubes.

[0038] The total reinforcing filler content of the composition typically varies from 10 to 100 parts per annum, preferably from 30 to 80 parts per annum or even from 30 to 55 parts per annum.

[0039] The composition may further include virgin carbon black, in particular 1 to 25 parts virgin carbon black, as a reinforcing filler and / or precipitated silica.

[0040] In some embodiments, the composition of the invention comprises, as the only reinforcing fillers, pyrolysis carbon black and carbon nanotubes.

[0041] In some embodiments, the reinforcing fillers consist essentially of pyrolysis carbon black and carbon nanotubes.

[0042] Pyrolysis carbon black

[0043] For the purposes of this invention, "pyrolysis carbon black" means carbon black obtained by pyrolyzing a material comprising at least one carbon polymer and carbon black, hereinafter referred to as the material to be pyrolyzed, for example, in the context of recycling such a material. The physical state of the material to be pyrolyzed is irrelevant, whether it is in the form of powder, granules, strips, or any other form, and whether it is cross-linked or non-cross-linked.

[0044] Preferably, the material to be pyrolyzed can be recovered from manufactured articles or products generated during their manufacture / production (such as by-products or scrap); these manufactured articles can be selected from the group consisting of pneumatic tires, non-pneumatic tires, industrial conveyor belts, transmission belts, rubber seals, rubber hoses, shoe soles, and windshield wipers. More preferably still, the pyrolysis carbon black usable within the scope 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 selected from the group consisting of pneumatic and non-pneumatic tires.

[0045] Pyrolysis, as defined in the present invention, means any type of thermal decomposition in the absence of oxygen, where the raw material is the material to be pyrolyzed as defined above. Pyrolysis carbon blacks are therefore distinguished from virgin carbon blacks, also known as industrial and / or ASTM grade carbon blacks, in that the carbonaceous 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, coal, natural oils, or oils obtained from recycling processes (such as pyrolysis oil).

[0046] The pyrolysis carbon blacks usable within the framework of the present invention are distinguished from known carbon blacks such as industrial carbon blacks, in particular so-called "furnace" carbon blacks, notably by a higher ash content.

[0047] Preferably, the pyrolysis carbon black usable within the framework of the present invention has an ash content in the range of 5 to 30% by weight, more preferably in the range of 8 to 25% by weight, more preferably in the range of 10% to 22% by weight, relative to the total weight of the pyrolysis carbon black.

[0048] Preferably, the pyrolysis carbon black usable within the framework of the present invention has a sulfur content greater than 2% by weight, preferably 2.5 to 5% by weight, relative to the total weight of the pyrolysis carbon black.

[0049] Preferably, the pyrolysis carbon black usable within the framework of the present invention has a zinc content greater than or equal to 2% by weight, preferably 2.5 to 8% by weight, relative to the total weight of the pyrolysis carbon black.

[0050] Preferably, the pyrolysis carbon black usable within the scope of the present invention has a specific surface area STSA measured according to ASTM D 6556-2021 within a range of 20 to 200 m² 2 / g, more preferentially ranging from 30 to 90 m 2 / g.

[0051] Preferably, the pyrolysis carbon black usable within the framework of the present invention has a void volume measured according to ASTM D7854-21 and at a pressure of 50 MPa within a range of 30 to 60 ml / 100g, more preferably within a range of 35 to 55 ml / 100g.

[0052] 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 identified before each series of measurements and tared to the nearest 0.1 mg; its mass is noted as PO. Five grams of pyrolysis carbon black sample are introduced into the capsule and weighed precisely to the nearest 0.1 mg; this mass is noted as 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 placed in a muffle furnace heated to 825°C for 1 hour. After 1 hour, 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 mass P2.Finally, it is possible to obtain the ash content (% ash) using the formula below:

[0053] [Math 1]

[0054] P 2 — PO'

[0055] % ash = — — — — x 100

[0056] PI — PO

[0057] The zinc content in pyrolysis carbon black is determined after calcination of the sample, followed by resuspension of the ash in an acidic medium and analysis by ICP-AES (inductively coupled plasma atomic emission spectroscopy). The ash is obtained using the protocol described above. Approximately 100 mg of ash (test sample) is taken and placed in a PFA (perfluoroalkoxy) tube for use with a HotBiock hot 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. The tube is then capped 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). Ultrapure water is then added to the calibration mark.The resulting solution is diluted 100-fold by taking 1 mL from a 100 mL PTFE 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 µm GHP syringe filter before being analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Prior to the analysis of the diluted solution, at least five 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 commercially available solution certified to a zinc concentration of 1 g / L.

[0058] These volumetric flasks initially 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 ΔZn = 202.613 nm. For each standard concentration (c), the zinc signal intensity IZn is plotted on a graph IZn = f(c), which corresponds to the calibration curve (of the 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 curve obtained previously. This yields the concentration [c] cendres in mass % directly by the software, since the test sample and volume were previously recorded. The zinc concentration in the pyrolysis black [c] nO The mass percentage of ir is obtained using the following equation:

[0059] [Math 2]

[0060] H black H ash * 100 * % ash

[0061] The determination of sulfur content in pyrolysis carbon black is carried out using a 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 of the sample, the sampling chambers are cleaned and the furnace is calibrated. The LECO furnace chambers are cleaned beforehand: the empty chamber is analyzed under the same conditions as the samples. The calibration curve is prepared using a commercial standard called "BBOT" with a purity greater than 99.99% and a guaranteed carbon (C), hydrogen (H), nitrogen (N), oxygen (O), and sulfur (S) content. This content is as follows: C%: 72.52; H%: 6.09; N%: 6.51; O%: 7.43; and S%: 7.44. We weigh approximately exactly 10 ± 3, 20 ± 3 and 40 ± 3 mg of BBOT in a capsule.The standard / pod 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 sample to combust and release sulfur and / or carbon as SO2(g). After 20 seconds, oxygen begins to flow through the lance to accelerate the combustion of materials that are difficult to burn. The sulfur and / or carbon, as SO2(g), are carried by an oxygen flow through the infrared detection cells. The instrument software plots a line connecting the introduced standard mass and the observed response (area) on the detector. This yields a calibration curve. After thoroughly cleaning the sampling equipment, approximately 80 ± 5 mg of pyrolysis carbon black is weighed and introduced into a LECO furnace pod.The area of ​​the observed SO2 peak is related to the concentration using the calibration curve. The instrument's software then calculates the mass percentage of sulfur in the sample based on the sample mass introduced into the capsule. Pyrolysis carbon blacks are commercially available, for example, from Scandinavian Enviro Systems under the reference "P550 HD" or from Bolder Industries under the reference BolderBlack.

[0062] Carbon nanotubes

[0063] Carbon nanotubes are allotropes of carbon that exhibit a unique atomic structure composed of covalently bonded carbon atoms arranged in long cylinders.

[0064] The carbon nanotubes useful in the context of the present invention may be made of one or more rolled graphite sheets. The nanotubes may be of the single-walled (SWNT) or multi-walled (MWNT) type.

[0065] The carbon nanotubes useful in the context of the present invention typically have an average diameter ranging from 0.1 to 200 nm, preferably from 0.1 to 100 nm, more preferably from 0.4 to 50 nm, and even better, from 1 to 30 nm, or even from 10 to 15 nm, and advantageously an average length of more than 0.1 pm, advantageously from 0.1 to 20 pm, preferably from 0.1 to 10 pm, for example, about 6 pm. Their length-to-diameter ratio is advantageously greater than 10 and most often greater than 100. The average length and average diameter of the carbon nanotubes can be conventionally determined by transmission electron microscopy (TEM). The average diameter is the average value of all the diameters measured using nm as the unit. The average length is determined by the average value of all the lengths measured.

[0066] The carbon nanotubes useful in the context of the present invention can have closed and / or open ends. These nanotubes are generally obtained by chemical vapor deposition. Their specific surface area, for example, ranges from 100 to 300 m². 2 / g, advantageously from 200 to 300 m 2 / g. Their apparent density can range from 0.01 to 0.5 g / cm³. 3 and more preferably from 0.07 to 0.2 g / cm² 3 Multi-walled carbon nanotubes can, for example, comprise from 5 to 15 layers and more preferably from 7 to 10 layers.

[0067] Carbon nanotubes can in particular be manufactured from a renewable source (bio-ethylene derived from bioethanol).

[0068] An example of carbon nanotubes that can be used in the context of the invention is, in particular, the commercial reference Graphistrength® C100 from the company Arkema.

[0069] Virgin carbon black

[0070] The elastomeric composition may also include a carbon black different from pyrolysis carbon black; this carbon black is also called "virgin carbon black" because it is not produced from materials that already contain carbon black. Virgin carbon black is produced from materials derived from petroleum fractions or coal, or from natural oils or oils obtained through recycling processes (such as pyrolysis oil).

[0071] As virgin carbon blacks, all carbon blacks are suitable, including carbon blacks conventionally used in tires or their treads, especially industrial carbon blacks, more specifically so-called "furnace" carbon blacks.

[0072] Among virgin carbon blacks, special mention should be made of reinforcing virgin carbon blacks of the 100, 200, 300 series, or blacks of the 500, 600 or 700 series (ASTM grades D-1765-2023b), such as for example blacks N115, N 134, N234, N326, N330, N339, N347, N375, N550, N683, N772.

[0073] Virgin carbon blacks can be used in their isolated state, as commercially available, or in any other form, for example as a carrier for certain rubberizing additives used. Virgin carbon blacks could, for example, already be incorporated into diene elastomers, particularly isoprene elastomers, in the form of a masterbatch (see, for example, applications WO97 / 36724-A2 or W099 / 16600-A1).

[0074] Siliceous or aluminous mineral fillers

[0075] Suitable inorganic reinforcing fillers include mineral fillers of the siliceous type, preferably silica (SiO2), or of the aluminous type, particularly alumina (Al2O3). The silica used may be any reinforcing silica known to those skilled in the art, including precipitated or fumed silica.

[0076] Precipitated silica can be produced from non-renewable raw materials, including those derived from inorganic sand (silicon dioxide from inorganic sand), recycled materials such as foundry sands, end-of-life tires and in particular the treads of end-of-life tires which mainly contain silica as a reinforcing filler, or from bio-based raw materials such as organic waste from plants, preferably inedible organic waste from plants.

[0077] Non-renewable raw materials are defined as raw materials that do not regenerate on a human timescale. These are therefore exhaustible resources. Examples include minerals such as stones or sand, metals, gas, and oil.

[0078] Among the plants that have silicon dioxide in their tissues are mustard, grasses, corn, sugar cane bagasse, rice, wheat and in particular mustard husks, bamboo leaves, ears of corn, rice husks, wheat husks.

[0079] Silica derived from non-renewable raw materials such as natural inorganic sand is usually obtained by heating sand in a glass furnace in the presence of sodium carbonate. The resulting sodium silicate is then dissolved in water, possibly in the presence of a base such as sodium hydroxide. Precipitated synthetic silica is formed from this aqueous solution by controlled treatment of the silicate with an acid (e.g., a mineral acid and / or an acidifying gas such as carbon dioxide). Sometimes, an electrolyte (e.g., sodium sulfate) may be present to promote the formation of precipitated silica particles. The recovered precipitated silica is amorphous.

[0080] Silica derived from bio-based raw materials such as those mentioned above can, for example, be obtained by burning the bio-based raw material in order to recover the ash of this bio-based material which contains mainly silicon dioxide.For example, with rice husks, and in a process equivalent to the one described above for silicas based on non-renewable or recycled mineral raw materials, rice husk ash is generally treated with a strong base such as sodium hydroxide to form an aqueous silicate solution (e.g., sodium silicate). Following this, precipitated synthetic silica is formed by the controlled addition of an acid (e.g., a mineral acid and / or an acidifying gas such as carbon dioxide) in which an electrolyte (e.g., sodium sulfate) may be present to promote the formation of precipitated silica particles derived from rice husks. The recovered precipitated silica is amorphous precipitated silica. Silica derived from rice husk ash is commonly referred to as RHA silica (Rice Husk Ash Silica).Bio-based silicas are available, for example, from suppliers such as Solvay, Evonik, Quechen, Wilmar International, Wuxi.

[0081] In summary, the synthesis of a precipitated silica usable within the framework of the invention can be carried out from a sodium silicate entirely obtained from bio-based, recycled or non-renewable raw materials, but also from a mixture of bio-based and / or recycled and / or non-renewable raw materials.

[0082] Preferably, precipitated silica, whether obtained from mineral, non-renewable, recycled or bio-based raw materials, has a specific surface area and a CTAB specific surface area both below 450 m² 2 / g, preferably within a range of 30 to 400 m 2 / g, particularly from 60 to 300 m 2 / g.

[0083] Any type of precipitated silica can be used, including highly dispersible precipitated silicas (known as "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 W003 / 016215-A1 and W003 / 016387-A1. Among the commercially available HDS silicas, the following can be used: "Ulsilsil® 5000GR" and "Ulsilsil® 7000GR" from Evonik, and "Zeosil® 1085GR", "Zeosil® 1115 MP", "Zeosil® 1165 MP", "Zeosil® Premium 200 MP", and "Zeosil® HRS 1200 MP" from Solvay.As non-HDS silica, the following commercial silicas may be used: “Ultrasil® VN2GR”, “Ultrasil® VN3GR” silicas from Evonik, “Zeosil® 175GR” silica from Solvay, “Hi-Sil EZ120G(-D)”, “Hi-Sil EZ160G(-D)”, “Hi-Sil EZ200G(-D)”, “Hi-Sil 243LD”, “Hi-Sil 210”, “Hi-Sil HDP 320G” silicas from PPG, “K160”, “K185”, “K195” silicas from Wilmar International.

[0084] Other examples of inorganic fillers that may be used in compositions include mineral fillers of the aluminous type, in particular alumina (Al2O3), aluminum oxides, aluminum hydroxides, aluminosilicates, titanium oxides, silicon carbides or nitrides, all of the reinforcing type as described for example in 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 747087-B2. Examples include the aluminas “BaikaloxA125” or “CR125” (Baïkowski company), “APA-100RDX” (Condéa), “Aluminoxid C” (Evonik) or “AKP-G015” (Sumitomo Chemicals).

[0085] The physical state of the reinforcing inorganic filler is irrelevant, whether it be in the form of powder, microbeads, granules, spheres, or any other suitable densified form. Of course, the term "reinforcing inorganic filler" also refers to mixtures of different reinforcing inorganic fillers, particularly silicas as described above.

[0086] Those skilled in the art will understand that, in place of the inorganic reinforcing 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 has 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.

[0087] A person skilled in the art will be able to adapt the total rate of reinforcing load according to the use concerned, in particular according to the type of tire concerned, for example tire for motorcycle, for passenger vehicle or for utility vehicle such as van or heavy goods vehicle.

[0088] To couple the reinforcing inorganic filler to the diene elastomer, a well-known coupling agent (or bonding agent) can be used to ensure sufficient chemical and / or physical connection between the inorganic filler (the surface of its particles) and the diene elastomer. Organosilanes or polyorganosiloxanes, at least bifunctional, are particularly suitable. "Bifunctional" refers to a compound possessing a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the diene elastomer.For example, such a bifunctional compound may comprise a first functional group comprising a silicon atom, said first functional group being able to interact with the hydroxyl groups of an inorganic charge and a second functional group comprising a sulfur atom, said second functional group being able to interact with the diene elastomer.

[0089] Preferably, organosilanes are chosen from the group consisting of polysulfide organosilanes (symmetric or asymmetric) such as bis(3-triethoxysilyl propyl) tetrasulfide, abbreviated TESPT and marketed as "Si69" by Evonik, or bis-(triethoxysilyl)propyl disulfide, abbreviated TESPD and marketed as "Si75" by Evonik; polyorganosiloxanes; mercaptosilanes; and blocked mercaptosilanes, such as S-(3-(triethoxysilyl)propyl octanethioate) marketed by Momentive as "NXT Silane". More preferably, the organosilane is a polysulfide organosilane.

[0090] A person 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,

[0091] 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.

[0092] The coupling agent content preferably represents 0.5% to 15% by weight relative to the amount of reinforcing inorganic filler, preferably 4% to 12%, and preferably 6% to 10% by weight relative to the amount of reinforcing inorganic filler. Typically, the coupling agent content is less than 20%, preferably within the range of 6% to 17%, and preferably 8% to 15%. This percentage can easily be adjusted by a person skilled in the art according to the amount of inorganic filler used in the composition.

[0093] The composition may also contain, in addition to coupling agents, coupling activators, inorganic filler covering agents or more generally processing aids which are known to improve the dispersion of the filler in the elastomer matrix and to lower the viscosity of the compositions, thereby improving their processing ability 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 trialcanol-amines), hydroxylated or hydrolyzable POS, for example α,ε-dihydroxy-polyorganosiloxanes (in particular α,ε-dihydroxy-polydimethylsiloxanes), fatty acids such as stearic acid.

[0094] Other organic charges

[0095] Examples of organic fillers other than carbon blacks and pyrolysis carbon blacks include functionalized polyvinyl organic fillers as described in applications WO 2006 / 069792-A1, WO 2006 / 069793-A1, WO 2008 / 003434-A1 and WO 2008 / 003435-A1.

[0096] Crosslinking system

[0097] The elastomeric composition of the invention includes a crosslinking system.

[0098] 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 may, in particular, be based on sulfur, and / or peroxide, and / or bismaleimides.

[0099] Preferably, the crosslinking system is sulfur-based; this is then referred to as a vulcanization system.

[0100] Sulfur can be supplied in any form, including as molecular sulfur, or as a sulfur donor agent.

[0101] A sulfur donor is defined as any compound that releases sulfur atoms, whether combined or not in the form of a polysulfide chain, capable of inserting themselves into the polysulfide chains formed during vulcanization and bridging the elastomeric chains. The sulfur content in the elastomeric composition is preferably less than 10 parts per million (ppm), preferably within the range of 1 to 8 ppm, and more preferably within the range of 2 to 6 ppm.

[0102] Any compound capable of accelerating the vulcanization of diene elastomers in the presence of sulfur may be used as a vulcanization accelerator (primary or secondary). This includes, in particular, thiazole-type accelerators and their derivatives, sulfenamide-type accelerators, guanidine-type accelerators, thiuram-type accelerators, dithiocarbamate-type accelerators, dithiophosphate-type accelerators, thiourea-type accelerators, and xanthate-type accelerators. The vulcanization accelerator may be used at a preferential rate in the range of 0.3 to 5 parts per million (ppm), more preferably from 0.5 to 3.5 ppm.

[0103] As is well known, the vulcanization system may also include vulcanization activators such as metal oxides like zinc oxide or fatty acids such as stearic acid.

[0104] Common additives and processing aids

[0105] The elastomeric composition of the invention may also include all or part of the usual additives and processing agents known to those skilled in the art and commonly used in elastomeric compositions for tires, such as plasticizing agents (such as plasticizing oils and / or plasticizing resins), non-reinforcing fillers, pigments, raw tack promoters (i.e., tackifying agents), pro-oxidant metallic salts, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents, reinforcing resins (such as described, for example, in application WO 02 / 10269).

[0106] Preferably, the rate of plasticizing agent(s) in the elastomeric composition is in a range of 0 to 20 pc, more preferably in a range of 0 to 10 pc.

[0107] Composition manufacturing

[0108] The elastomeric composition of the invention is manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art:

[0109] - a first thermomechanical working or mixing phase (the 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 standard internal mixer (for example, of the 'Banbury' type), including the highly saturated diene elastomer as defined above, the reinforcing filler(s) including pyrolysis carbon black, and any other miscellaneous 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 the range of 110°C to 200°C, for a duration generally in the range of 2 to 10 minutes;

[0110] - a second mechanical working phase (the 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 the whole is then mixed for a few minutes, for example from 5 to 15 min.

[0111] The final elastomeric composition thus obtained is then calendered, for example in the form of a sheet or plate, particularly for characterization in the laboratory, or extruded in the form of a semi-finished (or profile) of rubber.

[0112] The elastomeric composition can be either in its raw state (before crosslinking or vulcanization) or in its cured state (after crosslinking or vulcanization), and can be a semi-finished product suitable for use in a tire. 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 within the range of 130°C to 200°C, preferably under pressure, for a sufficient time, which may vary, for example, from 5 to 90 minutes.

[0113] Rubber items

[0114] Another object of the present invention relates to a rubber article comprising at least one elastomeric composition as defined above.

[0115] The rubber article can be any type of article such as a hose, pipe, seal, O-ring, drive belt, engine mount, electrical cable insulation, shoe sole, semi-finished article for pneumatic bandages, semi-finished article for non-pneumatic bandages, a pneumatic bandage or a non-pneumatic bandage.

[0116] 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. Preferably, the rubber article is a semi-finished article for pneumatic tires, the semi-finished article being chosen from the group consisting of carcass plies, apex plies, bracing plies, bead padding, apex feet, decoupling layers, seat layers located in the chafer area, and combinations thereof.

[0117] Preferably, the rubber article is a pneumatic tire comprising at least one elastomeric composition according to the present invention or comprising a semi-finished article for pneumatic tires, the semi-finished article being selected from the group consisting of carcass plies, top plies, bracing plies, bead padding, top feet, decoupling layers, seat layers located in the chafer area and combinations thereof.

[0118] Semi-finished products for pneumatic or non-pneumatic bandages are rubber products intended for the manufacture of pneumatic or non-pneumatic bandages.

[0119] By "pneumatic tire" we mean a tire designed to form a cavity by cooperating with a support element, for example a rim, this cavity being capable of being pressurized to a pressure greater than atmospheric pressure.

[0120] In contrast, a "non-pneumatic tire" is a tire that supports the load of a vehicle by means other than pressurized inflation gas. Thus, a non-pneumatic tire is a toroidal body made of at least one polymeric material, designed to perform the function of a tire but without being subjected to inflation pressure. A non-pneumatic tire can be solid or hollow. A hollow non-pneumatic tire may contain air, but at atmospheric pressure; that is, it does not have the pneumatic rigidity provided by inflation gas at a pressure higher than atmospheric pressure. Non-pneumatic tires are described, for example, in documents WO 03 / 018332 and FR2898077.

[0121] Pneumatic or non-pneumatic tires are intended to equip vehicles of all types, such as passenger vehicles or industrial vehicles such as heavy goods vehicles, vans, agricultural vehicles, buses, subways, civil engineering vehicles, aircraft and other handling vehicles.

[0122] The pneumatic or non-pneumatic tire, comprising (or having as its essential characteristic the inclusion of) the composition according to the invention, or a semi-finished article comprising at least one composition according to the invention, may be in its raw state (before crosslinking of the rubber composition) or in its cured state (after crosslinking of the rubber composition). Generally, during tire manufacturing, the composition is deposited in its raw state (i.e., before crosslinking of the rubber composition) into the tire structure prior to the tire curing stage.

[0123] Preferably, the rubber article is a pneumatic or non-pneumatic bandage comprising at least one semi-finished article made up in whole or in part of at least one elastomeric composition according to the invention.

[0124] The semi-finished article consisting in whole or in part of at least one elastomeric composition according to the invention can be chosen from the group consisting of carcass plies, top plies, shrink-fit plies, rod-fillers, top feet, decoupling layers, seat layers located in the chafer area and their combinations.

[0125] The carcass plies, top plies, and reinforcement plies may contain one or more reinforcing elements, each reinforcing element being embedded in the elastomeric composition according to the invention. The reinforcing elements comprise a wire element, which may be metallic or textile. A wire element is defined as an element having a length at least 10 times greater than the longest dimension of its cross-section, regardless of the shape of the latter: circular, elliptical, oblong, polygonal, and in particular rectangular, square, or oval. In the case of a rectangular cross-section, the wire element is in the form of a strip. The reinforcing elements are well known to those skilled in the art.

[0126] The following examples are given for illustrative purposes only, but should in no way be considered as limiting the present invention.

[0127] EXAMPLES

[0128] 1. Mooney Viscosity Measurement Method (ML 1+4)

[0129] The Mooney viscosity measurement is performed according to the following principle and in accordance with ASTM D-1646 (1999). The composition being analyzed in its raw state (i.e., before baking) is molded in a cylindrical chamber heated to a given temperature, usually 100°C. After one minute of preheating, an L-type rotor is spun inside the specimen at 2 revolutions per minute, and the torque required to maintain this rotation is measured after 4 minutes of rotation. The Mooney viscosity (ML 1+4) is expressed in "Mooney units" (MU, with 1 MU = 0.83 Newton-meters). As is well known to those skilled in the art, the lower the Mooney viscosity, the easier the material is to work.

[0130] All values ​​are given as a base of 100 relative to the given reference.

[0131] 2. Preparation of compositions

[0132] The compositions are prepared as follows: the diene elastomer(s), the reinforcing filler(s), and the various other ingredients, with the exception of the vulcanizing system, are successively introduced into an internal mixer (final filling rate: approximately 70% by volume), whose initial tank temperature is approximately 70°C. A thermomechanical process (non-productive phase) is then carried out in a single step, lasting approximately 3 to 4 minutes in total, until a maximum "drop" temperature of 165°C is reached.

[0133] The mixture thus obtained is collected, cooled, and then sulfur and an accelerator (sulfenamide) are incorporated on a mixer (homo-finisher) at 30°C by mixing (productive phase) for 5 to 12 min.

[0134] The elastomeric compositions thus obtained are then calendered into plates (2 to 3 mm thick) for the measurement of their physical or mechanical properties.

[0135] 3. Tests

[0136] The purpose of these tests is to demonstrate the improved compromise in properties obtained with the compositions of the invention compared to conventional control compositions used in various tire fittings. The ingredients of the different compositions are listed in the tables below, and the quantity of these ingredients is expressed in parts per hundred weight of elastomer.

[0137] 3.1 Elastomeric compositions for a carcass sheet [Table 1] Table 1

[0138] (1): Natural rubber

[0139] (2): Styrene and butadiene copolymer having a styrene unit content of 26% by weight relative to the total weight of the copolymer, a 1,2 butadiene unit content of 24% by weight relative to the weight of the butadiene portion and a 1,4 trans butadiene unit content of 47% by weight relative to the butadiene portion and a Tg of -54°C (3): MES / HPD oil marketed by Shell under the reference "Catenex SNR" (Tg = -60°C)

[0140] (4): Alkyl phenol formaldehyde tackifying resin marketed under the reference "SP1068" by the company SI group

[0141] (5): N-cyclohexyl-2-benzothiazyl-sulfenamide: “Santicure CBS” by Flexsys

[0142] (6): Stearic acid marketed under the reference "Pristerene 4931" by the company Uniqema

[0143] (7): Industrial grade zinc oxide marketed by Umicore

[0144] (8): Antioxidant: ((N-(1,3-dimethylbutyl)-N-phenyl-para-phenylenediamine marketed under the reference "Santaflex 6-PPD" by the company Flexsys,

[0145] (9): Virgin carbon black (also called conventional carbon black) of ASTM N347 grade (ASTM D1765-17) produced from petroleum-derived raw materials and having an ash content of less than 1% by weight and a sulfur content of less than 2% by weight, relative to the total weight of the virgin carbon black, the ash content and sulfur content being obtained according to the methods described above,

[0146] (10): Virgin carbon black (also called conventional carbon black) of ASTM N550 grade (ASTM D1765-17) produced from petroleum-derived raw materials and having an ash content of less than 1% by weight and a sulfur content of less than 2% by weight, relative to the total weight of the virgin carbon black, the ash content and sulfur content being obtained according to the methods described above,

[0147] (11): Pyrolysis carbon black “P550 HD” from Scandinavian Enviro Systems obtained by pyrolysis of end-of-life tires. The ash content is 18.5% by weight, the sulfur content is 3% by weight; the zinc content is 4.5% by weight (% by weight relative to the weight of the pyrolysis carbon black); the STSA specific surface area is 56 m² 2 / g (ASTM D6556-2021); the void volume at 50MPa is 44ml / 100g (ASTM D7854-21), the ash content, sulfur content and zinc content being obtained according to the methods described above.

[0148] (12): Carbon nanotubes marketed under the reference "Graphistrength® C100" by Arkema, having an average diameter of 12 nm, an average length ranging from 1 to 10 pm and a specific surface area ranging from 200 to 250 m² 2 / g.

[0149] The properties of these compositions are measured after cooking at 150°C for 15 minutes and are presented in Table 1 above.

[0150] Traction measurements

[0151] The tests were carried out in accordance with the French standard NF T 46-002 of September 1988. The tensile measurements were carried out under normal temperature (23±2°C) and humidity (50±5% relative humidity) conditions, according to the French standard NF T 40-101 (December 1979).

[0152] The nominal secant modulus, calculated by reducing the measurement to the initial cross-section of the specimen (or apparent stress, in MPa) at 10% elongation, denoted MA10 (modulus of elasticity under tension at 10% elongation), was measured at the second elongation (i.e., after accommodation) on cured samples. The results are expressed as a base of 100 relative to the control composition. When the value is greater than 100, the composition exhibits a higher MA10 modulus, and therefore a higher stiffness, than the control composition.

[0153] Measurement of

[0154] The dynamic properties are measured on a viscoanalyzer (Metravib VA4000), according to the ASTM D 5992-96 standard. The response of a sample of the vulcanized composition (cylindrical specimens 2 mm thick and 10 mm in diameter) is recorded, subjected to a sinusoidal loading in simple alternating shear, at a frequency of 10Hz, at a temperature of 60°C.

[0155] For measurements of the complex dynamic shear modulus (G*) and the loss factor tan(delta), a strain amplitude sweep is performed from 0.1% to 50% peak-to-peak (forward cycle), then from 50% to 0.1% peak-to-peak (return cycle). For the return cycle, the maximum observed tan(delta) value is recorded, denoted tan(delta)max 20% return; as well as the modulus G* at 20% strain, denoted G*20% return.

[0156] The value tan(delta)max is representative of the hysteresis of the material.

[0157] The lower the tan(delta) value at 60°C, the lower the hysteresis of the composition and therefore the lower the rolling resistance. The results are expressed in terms of performance base 100, meaning that the value 100 is arbitrarily assigned to the control, and then the tan(delta) (i.e., the hysteresis – and therefore the rolling resistance) of the different solutions tested is compared.

[0158] The value in base 100 is calculated according to the operation: (value of tan(delta) of the control / value of tan(delta) of the sample)*100. Thus, a lower value represents a decrease in hysteresis performance (i.e. an increase in hysteresis), while a higher value represents a better hysteresis performance (i.e. a lower hysteresis).

[0159] The data presented in Table 1 show that the use of pyrolysis carbon black as a reinforcing filler (as a substitute for conventional carbon black) negatively affects the processability of the compositions (Mooney viscosity) (A2 versus A1). Unexpectedly, the addition of carbon nanotubes to compositions containing pyrolysis carbon black improves the processability of the compositions. Indeed, the compositions according to the invention (A3 and A4) exhibit better processability than composition A2, which consists solely of pyrolysis carbon black as a reinforcing filler, while also displaying satisfactory stiffness (MA10) (A3 and A4 versus A1) and equivalent hysteresis (Tan delta).The compositions according to the invention therefore make it possible to obtain a better compromise between baked stiffness and raw stiffness than compositions comprising only pyrolysis carbon black as reinforcing fillers.

[0160] 3.2 Elastomeric compositions for the bead base layer [Table 2]

[0161] Table 2 Ingredients (1), (6), (7), (8), (11), (12) are the same as those in the compositions of Table 1. (13): Elastomer: Polybutadiene obtained by synthesis with a neodymium catalyst, the polybutadiene having a 1,2-unit content of 0.5%, a 1,4-cis-unit content of 97% and a 1,4-trans-unit content of 2.5%, with a Tg of -108°C

[0162] (14): Gem rosin from the Costa Irmaos company

[0163] (15): Liquid plasticizer: TDAE oil from Grupa LOTOS SA, glass transition temperature Tg = 85°C

[0164] (16): “Varazon 4959” wax from the Sasol Company

[0165] (17): N-ter-butyl-2-benzothiazyl sulfenamide marketed by Flexsys under the reference "Santocure TBBS".

[0166] The properties of these compositions are measured after cooking at 160°C for 13 minutes and are presented in Table 2 above.

[0167] Dynamic properties are measured on a viscoanalyzer (Metravib VA4000), according to ASTM D 5992-96. The response of a sample of the vulcanized composition (cylindrical specimens 2 mm thick and 10 mm in diameter) is recorded, subjected to sinusoidal loading in simple alternating shear, at a frequency of 10Hz, at a temperature of 23°C.

[0168] For measurements of the complex dynamic shear modulus (G*) and the loss factor tan(delta), a strain amplitude sweep is performed from 0.1% to 50% peak-to-peak (forward cycle), then from 50% to 0.1% peak-to-peak (return cycle). For the return cycle, the maximum observed tan(delta) value, denoted tan(delta)max, is recorded, as well as the modulus G* at 10% strain, denoted G*10%.

[0169] The value tan(delta)max is representative of the hysteresis of the material.

[0170] The results are expressed in terms of performance base 100, that is to say that the value 100 is arbitrarily assigned to the control, to then compare the tan(delta) (that is to say the hysteresis - and therefore the rolling resistance) of the different solutions tested.

[0171] The value in base 100 is calculated according to the operation: (value of tan(delta) of the control / value of tan(delta) of the sample)*100. Thus, a lower value represents a decrease in hysteresis performance (i.e. an increase in hysteresis), while a higher value represents a better hysteresis performance (i.e. a lower hysteresis).

[0172] The value tan(delta)max 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.

[0173] The G*10% values ​​measured at 23°C represent stiffness, i.e., resistance to deformation: the higher the G*10% value at 23°C, the greater the material's stiffness. All values ​​are expressed as a scale of 100 relative to a given reference.

[0174] It is observed that the composition according to the invention (C2) exhibits better processability (Mooney viscosity) than a composition comprising only pyrolysis carbon black as reinforcing fillers (C1), while exhibiting equivalent stiffness (G* 10%) and hysteresis (tan(delta)).

[0175] 3.3 Elastomeric compositions for a top sheet of shrinkage

[0176] [Table 3] Table 3

[0177] Ingredients (1), (6) (7), (9), (10), (12), (13), (14) are the same as those in the compositions in Table 1.

[0178] (18) Elastomer: Non-functionalized, non-extended styrene-butadiene copolymer having a styrene unit content of 26.5% by weight relative to the total copolymer weight, a butadiene unit content of 24% by weight relative to the butadiene portion weight and a cis butadiene unit content of 25% by weight relative to the butadiene portion weight and a Tg of -48°C.

[0179] (19) Plasticizer: TDAE oil from Grupa LOTOS SA Tg at 85°C.

[0180] The rubbery properties of these compositions are measured after baking at 165°C for 12 minutes and are presented in Table 3 above.

[0181] The dynamic properties are measured on a viscoanalyzer (Metravib VA4000), according to the ASTM D 5992-96 standard. The response of a sample of the vulcanized composition (cylindrical specimens 2 mm thick and 10 mm in diameter) is recorded, subjected to a sinusoidal loading in simple alternating shear, at a frequency of 10Hz, at a temperature of 60°C.

[0182] For measurements of the complex dynamic shear modulus (G*) and the loss factor tan(delta), a strain amplitude sweep is performed from 0.1% to 100% peak-to-peak (forward cycle), then from 100% to 0.1% peak-to-peak (return cycle). For the return cycle, the maximum observed tan(delta) value, denoted tan(delta)max, is recorded, as well as the modulus G* at 10% strain, denoted G*10%.

[0183] The value tan(delta)max is representative of the hysteresis of the material.

[0184] The results are expressed in terms of performance base 100, that is to say that the value 100 is arbitrarily assigned to the control, to then compare the tan(delta) (that is to say the hysteresis - and therefore the rolling resistance) of the different solutions tested.

[0185] The value in base 100 is calculated according to the operation: (value of tan(delta) of the control / value of tan(delta) of the sample) *100. Thus, a lower value represents a decrease in hysteresis performance (i.e., an increase in hysteresis), while a higher value represents a better hysteresis performance (i.e., lower hysteresis).

[0186] The value tan(delta)max 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.

[0187] The G*10% values ​​measured at 60°C are representative of the stiffness, i.e. the resistance to deformation: the higher the G*10% value at 60°C, the greater the stiffness of the material.

[0188] All values ​​are given as a base of 100 relative to a given reference.

[0189] It is observed that the compositions according to the invention (D2 and D3) exhibit better processability (Mooney viscosity) than a composition comprising only pyrolysis carbon black as reinforcing fillers (D1), while exhibiting satisfactory stiffness (G* 10%) and hysteresis (tan(delta)).

Claims

TJ DEMANDS 1. Elastomeric composition based on: a mixture of elastomers comprising 35 to 90 parts per cent of natural rubber (NR) or synthetic polyisoprenes (IR) or a mixture thereof, and 10 to 65 parts per cent of one or more diene elastomers selected from the group consisting of polybutadienes (BR), butadiene copolymers, and isoprene copolymers; reinforcing fillers comprising: - 10 to 85 pieces of pyrolysis carbon black; and - 1.0 to 10 pc of carbon nanotubes; of a crosslinking system.

2. Elastomeric composition according to claim 1 wherein the mixture of elastomers comprises from 35 to 90 parts per annum of natural rubber (NR) or synthetic polyisoprene (IR) or mixture thereof, and from 10 to 65 parts per annum of one or more polybutadienes (BR).

3. Elastomeric composition according to claim 1 wherein the mixture of elastomers comprises from 35 to 90 parts per annum of natural rubber (NR) or synthetic polyisoprenes (IR) or mixture thereof, and from 10 to 65 parts per annum of one or more diene elastomers selected from the group consisting of butadiene copolymers and isoprene copolymers, preferably selected from butadiene copolymers.

4. Elastomeric composition according to claim 3 wherein the butadiene copolymers are butadiene-styrene copolymers.

5. Elastomeric composition according to any one of claims 1 to 4 comprising from 10 to 45 pieces of pyrolysis carbon black.

6. Elastomeric composition according to any one of claims 1 to 5 comprising from 1.3 to 7.5 pc, more preferably from 1.5 to 6.5 pc, of carbon nanotubes.

7. Elastomeric composition according to any one of claims 1 to 6 wherein the reinforcing fillers consist essentially of pyrolysis carbon black and carbon nanotubes.

8. Elastomeric composition according to any one of claims 1 to 6, further comprising virgin carbon black and / or precipitated silica.

9. Elastomeric composition according to any one of claims 1 to 8 wherein the total content of reinforcing fillers varies from 10 to 100 parts per annum, more preferably from 30 to 80 parts per annum.

10. Elastomeric composition according to any one of claims 1 to 9, wherein the pyrolysis carbon black has an ash content of 5% to 30% by weight, preferably 8% to 25% by weight, relative to the total weight of the pyrolysis carbon black.

11. Elastomeric composition according to any one of claims 1 to 10, wherein the pyrolysis carbon black has a sulfur content greater than 2% by weight, preferably from 2.5% to 5% by weight, relative to the total weight of the pyrolysis carbon black.

12. Rubber article comprising at least one elastomeric composition according to any one of claims 1 to 11, the article preferably being selected from the group consisting of hoses, pipes, seals, O-rings, transmission belts, engine mounts, electrical cable insulators, shoe soles, semi-finished articles for pneumatic bandages, semi-finished articles for non-pneumatic bandages, non-pneumatic bandages and pneumatic bandages.

13. Rubber article according to claim 12, characterized in that it is a semi-finished article for pneumatic tires, said semi-finished article being selected from the group consisting of carcass plies, crown plies, shrink-fit plies, bead-fillers, crown feet, decoupling layers, seat layers located in the bead area and their combinations.

14. Rubber article according to claim 12, said article being a pneumatic tire comprising at least one composition as defined according to any one of claims 1 to 11 or comprising at least a semi-finished article as defined according to claim 13.

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