TIRE WITH AN OUTER SIDEWALL MADE FROM A COMPOSITION COMPRISING pyrolysis carbon black

Abstract

The present invention relates to pneumatic tires and more particularly to the outer sidewalls of tires, that is to say, by definition, to the elastomeric layers located radially on the outside of the tire, which are in contact with the ambient air.

Description

Title of the invention: TIRE WITH AN OUTER SIDEWALL BASED ON A COMPOSITION INCLUDING PYROLYSIS CARBON BLACK FIELD OF INVENTION

[0001] The present invention relates to pneumatic tires and more particularly to the outer sidewalls of tires, that is to say, by definition, to the elastomeric layers located radially outside the tire, which are in contact with the ambient air. TECHNOLOGICAL BACKGROUND

[0002] Within a tire, three zones are classically distinguished: - the radially outer zone in contact with the ambient air; - the radially inner area in contact with the inflation gas; - the inner area of ​​the tire.

[0003] The radially outer area in contact with the ambient air is essentially made up of the tread and the outer sidewall of the tire. An outer sidewall is an elastomeric layer disposed outside the carcass reinforcement relative to the internal cavity of the tire, between the crown and the bead so as to totally or partially cover the area of ​​the carcass reinforcement extending from the crown to the bead.

[0004] The radially inner area in contact with the inflation gas is generally made up of the layer that is airtight to the inflation gas, sometimes called the inner rubber (“inner liner” in English).

[0005] The inner zone of the tire is that between the outer and inner zones. This zone includes layers or plies which are referred to herein as the inner layers of the tire. These are, for example, carcass plies, tread sub-layers, tire belt plies, or any other layer that is not in contact with the ambient air or the tire inflation gas.

[0006] For tire performance, it is important that the outer sidewall area exhibits good rolling resistance. Good rolling resistance can be achieved by lowering the filler content of the rubber compounds and using primarily silica. However, it has been observed that lowering the filler content in the rubber compounds leads to processability problems, particularly uncontrollable swelling of the compounds. making them unsuitable for use in industrial equipment commonly used for tire manufacturing.

[0007] Thus, there remains a need for the provision of compositions which have both good processability and good performance in the cured state, particularly in terms of rolling resistance, and which advantageously meet an increasingly present need to limit the environmental impact of the manufacture and use of tires. BRIEF DESCRIPTION OF THE INVENTION

[0008] The present invention relates to a tire having an outer sidewall, the outer sidewall comprising at least one rubber composition based on:

[0009] - at least one elastomer;

[0010] - 16 to 20% by volume, relative to the total volume of the composition, of fillers reinforcing; and

[0011] - a crosslinking system;

[0012] reinforcing charges comprising: - 6 to 16%, preferably 6 to 11%, by volume, relative to the total volume of the composition, of reinforcing fillers selected from the group consisting of inorganic reinforcing fillers, carbon blacks having a CTAB specific surface area greater than or equal to 90 m2 / g and mixtures of inorganic reinforcing fillers and carbon blacks having a CTAB specific surface area greater than or equal to 90 m2 / g in which the inorganic reinforcing filler is predominant by mass; - pyrolysis carbon blacks in sufficient quantity to achieve a volume of reinforcing fillers in the composition ranging from 16% to 20% relative to the total volume of the composition.

[0013] Other aspects of the invention are as described below and in the claims. 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), it is to be understood in the context of the present invention, the part, by mass per hundred parts by mass of elastomer or rubber, the two terms being synonymous.

[0016] In the present, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0017] 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 at least 51% of the total mass of the compounds of the same type in the composition. For example, in a system comprising a single elastomer, this 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 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 at least 51% of the total mass of fillers in the composition.

[0018] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​from greater than a to less than b (i.e., excluding the bounds a and b), while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​from a to b (i.e., including the strict bounds a and b). In the present case, when an interval of values ​​is described by the expression "from a to b", the interval represented by the expression "between a and b" is also and preferably described.

[0019] The term "radial" refers to a radius of the tire. It is in this sense that a point P1 is said to be "radially inside" a point P2 (or "radially inside" point P2) if it is closer to the axis of rotation of the tire than point P2. Conversely, a point P3 is said to be "radially outside" a point P4 (or "radially outside" point P4) if it is farther from the axis of rotation of the tire than point P4. We say that we are moving "radially inward (or outward)" when we are moving in the direction of smaller (or larger) radii. This meaning of the term also applies when referring to radial distances.

[0020] By "radial cut" or "radial section" we mean here a cut or section along a plane which contains the axis of rotation of the tire.

[0021] An "axial" direction is a direction parallel to the axis of rotation of the tire. A point P5 is said to be "axially inside" a point P6 (or "axially inside" point P6) if it is closer to the median plane of the tire than point P6. Conversely, a point P7 is said to be "axially outside" a point P8 (or "axially outside" point P8) if it is further from the median plane of the tire than point P8. The "median plane" of the tire is the plane which is perpendicular to the axis of rotation of the tire and which is located equidistant from the annular reinforcement structures of each bead.

[0022] A “circumferential” direction is a direction that is perpendicular to both a radius of the tire and the axial direction.

[0023] The carbon-containing compounds mentioned in the description may be of fossil origin or bio-based. In the latter case, they may be partially or totally derived from biomass or obtained from renewable raw materials derived from biomass. This includes, in particular, polymers, plasticizers, fillers, etc. DETAILED DESCRIPTION OF THE INVENTION

[0024] The inventors have developed rubber compositions that meet the stated requirements. It has been shown that adding pyrolysis carbon black to a rubber composition increases the filler content of the composition, thus improving its processability, without compromising the composition's performance.

[0025] Thus, the present invention relates to a tire provided with an outer sidewall, the outer flank comprising at least one rubber composition based on:

[0026] - at least one elastomer;

[0027] - 16 to 20% by volume, relative to the total volume of the composition, of fillers reinforcing; and

[0028] - a crosslinking system;

[0029] reinforcing charges comprising: - 6 to 16%, preferably 6 to 11%, by volume, relative to the total volume of the composition, of reinforcing fillers selected from the group consisting of inorganic reinforcing fillers (preferably silica), carbon blacks having a CTAB specific surface area greater than or equal to 90 m2 / g and mixtures of inorganic reinforcing fillers (preferably silica) and carbon blacks having a CTAB specific surface area greater than or equal to 90 m2 / g in which the inorganic reinforcing filler (preferably silica) is predominant by mass; - pyrolysis carbon blacks in sufficient quantity to achieve a volume of reinforcing fillers in the composition ranging from 16% to 20% relative to the total volume of the composition.

[0030] The rubber composition may also include common additives and processing agents.

[0031] The different constituents of the rubber composition can be as described below. Elastomer

[0032] The composition useful within the framework of the present invention is based on at least one elastomer (or indistinctly rubber).

[0033] The elastomer can be chosen from the group consisting of diene elastomers and mixtures thereof.

[0034] By "diene" elastomer, whether natural or synthetic, is to be understood in a known way as an elastomer consisting at least in part (i.e., a homopolymer or a copolymer) of diene monomer units (monomers bearing two carbon-carbon double bonds, conjugated or not).

[0035] These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". Generally, "essentially unsaturated" means a diene elastomer derived at least in part from conjugated diene monomers, having a proportion of diene motifs or units (conjugated dienes) greater than 15% (mole percent); thus, diene elastomers such as butyl rubbers or EPDM-type diene-alpha-olefin copolymers do not fall under the preceding definition and can, in particular, be described as "essentially saturated" diene elastomers (low or very low proportion of diene motifs, always less than 15%).

[0036] The term "diene elastomer suitable for use" specifically means:

[0037] (a) - any homopolymer obtained by polymerization of a diene monomer, conjugated or not, having from 4 to 18 carbon atoms;

[0038] (b) - any copolymer obtained by copolymerization of a diene, conjugated or not, having from 4 to 18 carbon atoms and at least one other monomer.

[0039] The other monomer may be ethylene, an olefin or a diene, conjugated or not.

[0040] Suitable conjugated dienes are those having from 4 to 12 atoms of carbon, in particular 1,3-dienes, such as 1,3-butadiene and isoprene.

[0041] Suitable olefins are vinylaromatic compounds having 8 to 20 carbon atoms and aliphatic α-monoolefins having 3 to 12 carbon atoms.

[0042] Suitable examples of vinylaromatic compounds include styrene, ortho-, meta-, para-methylstyrene, the commercial "vinyl-toluene" mixture, para-tert-butylstyrene.

[0043] As aliphatic α-monoolefins, acyclic aliphatic α-monoolefins having from 3 to 18 carbon atoms are particularly suitable.

[0044] More specifically, the diene elastomer that may be used in the compositions may be:

[0045] (a') - any homopolymer obtained by polymerization of a conjugated diene monomer having 4 to 12 carbon atoms;

[0046] (b') - any copolymer obtained by copolymerization of one or more dienes conjugated with each other or with one or more vinylaromatic compounds having 8 to 20 carbon atoms;

[0047] (c') - any copolymer obtained by copolymerization of one or more dienes, conjugated or not, with ethylene, an α-monoolefin or their mixture, such as for example elastomers obtained from ethylene, propylene with an unconjugated diene monomer of the aforementioned type.

[0048] Preferably, the diene elastomer is chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers. Butadiene copolymers are particularly chosen from the group consisting of butadiene-styrene copolymers (SBR).

[0049] The diene elastomer can be modified, i.e. either coupled and / or star-shaped, or functionalized, or coupled and / or star-shaped and simultaneously functionalized.

[0050] Thus, the diene elastomer can be coupled and / or star-shaped, for example by means of a silicon or tin atom which links the elastomer chains together.

[0051] The diene elastomer can be simultaneously or alternatively functionalized and comprise at least one functional group. By functional group is meant a group comprising at least one heteroatom selected from Si, N, S, O, P. Particularly suitable as functional groups are those comprising at least one function such as: silanol, an alkoxysilane, a primary, secondary or tertiary amine, cyclic or non-cyclic, a thiol, an epoxide.

[0052] The rubber composition useful within the framework of the invention may contain a single diene elastomer or a mixture of several diene elastomers.

[0053] In certain embodiments, the rubber composition useful within the framework of the invention comprises one or more elastomers, it may thus comprise from 25 to 100 parts natural rubber and from 0 to 75 parts at least one polybutadiene, preferably from 35 to 75 parts natural rubber and from 25 to 65 parts at least polybutadiene.

[0054] In certain embodiments, the rubber composition useful within the scope of the invention comprises, as an elastomer, a mixture of natural rubber (NR) and at least one polybutadiene (BR). Preferably, the mixture consists of 50 parts natural rubber (NR) and 50 parts polybutadiene (BR). Reinforcing load

[0055] The composition useful within the framework of the present invention comprises reinforcing fillers. The reinforcing fillers represent 16 to 20% by volume of the total volume of the composition.

[0056] The term "reinforcing filler" commonly refers to any type of filler known for its ability to reinforce a rubber composition usable in particular for the manufacture of tires, for example organic fillers such as carbon black or pyrolysis carbon black, or inorganic fillers such as silica or alumina.

[0057] The composition useful within the scope of the present invention comprises: - 6 to 16%, preferably 6 to 11%, by volume, relative to the total volume of the composition, of reinforcing fillers selected from the group consisting of inorganic reinforcing fillers (preferably silica), carbon blacks having a CTAB specific surface area greater than or equal to 90 m2 / g and mixtures of inorganic reinforcing fillers (preferably silica) and carbon blacks having a CTAB specific surface area greater than or equal to 90 m2 / g in which the inorganic reinforcing filler (preferably silica) is predominant by mass; - pyrolysis carbon blacks in sufficient quantity to achieve a volume of reinforcing fillers in the composition ranging from 16% to 20% relative to the total volume of the composition.

[0058] Typically, mixtures of inorganic fillers (preferably silica) and carbon blacks having a specific surface area CTAB greater than or equal to 90 m2 / g in which the inorganic filler is predominant by mass comprise 10 volumes of inorganic fillers for 2 to 3 volumes of carbon blacks.

[0059] The specific surface area CTAB is determined according to the French standard NF T 45-007 of November 1987 (method B).

[0060] The reinforcing loads can be as described below. Pyrolysis carbon black

[0061] 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 powder, granule, strip, or any other form, and whether it is crosslinked or non-crosslinked.

[0062] 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 The group consists of pneumatic tires, non-pneumatic tires, industrial conveyor belts, transmission belts, rubber seals, rubber hoses, shoe soles, and windshield wipers. More preferably, the pyrolysis carbon black usable within the scope of the present invention is a carbon black obtained from a pyrolysis process where the material to be pyrolyzed is derived from manufactured articles selected from the group consisting of pneumatic tires and non-pneumatic tires.

[0063] Pyrolysis in the context of 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 so-called 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, or natural oils.

[0064] 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 "fumace" carbon blacks, notably by a higher ash content.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] Preferably, the pyrolysis carbon black usable within the framework of the present invention has a specific surface area STSA measured according to ASTM D 6556-2021 in the range of 20 to 200 m2 / g, more preferably in the range of 30 to 90 m2 / g.

[0069] Preferably, the pyrolysis carbon black usable within the scope 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 ranging from 35 to 55 ml / 100g.

[0070] The ash content is determined by calcination in platinum capsules in a muffle furnace at 825°C according to the following protocol. One capsule is pre-identified before each series of measurements and is tare weighted to the nearest 0.1 mg; its mass is denoted PO. Five grams of a sample of pyrolysis carbon black, weighed precisely to the nearest 0.1 mg, are introduced into the capsule; this mass is denoted PI. 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: .

[0071] [Math.l] P 2 - PO % centers pQx 100

[0072] 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 quantification by ICP-AES (inductively coupled plasma atomic emission spectroscopy). The ash is obtained by following the above protocol. Approximately 100 mg of ash (test sample) is taken and placed in a PFA (perfluoroalkoxy) tube for use with a HotBlock hot plate. 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, and 0.5 mL of 40% hydrofluoric acid are then added. The tube is sealed with its stopper 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 [unspecified location]. 100 mL volumetric flasks, by dilution of a commercial solution certified to a zinc concentration of 1 g / L.

[0073] 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 λZn = 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. The ash concentration [c] in mass % is thus obtained directly by the software, since the sample size and volume have been previously recorded. The concentration of zinc in pyrolysis black [c]black in mass % is obtained by the following equation:

[0074] [Math.2]

[0075] The determination of the 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 pods are cleaned and the furnace is calibrated. The LECO furnace pods are cleaned beforehand: the empty pod 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; 0% 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 burn and releases 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's software plots a straight line connecting the introduced standard mass and the observed response (area) on the detector. This yields a calibration curve. After... After thoroughly cleaning the sampling equipment, approximately 80 ± 5 mg of pyrolysis carbon black is weighed and placed in a LECO furnace capsule. 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 in the capsule.

[0076] Pyrolysis carbon blacks are marketed for example by the company BlackBear under the reference “BBCT30” or by the company Scandinavian Enviro Systems under the reference “P550”. Carbon black

[0077] As suitable carbon blacks, all carbon blacks are suitable, including those conventionally used in tires or their treads, in particular industrial carbon blacks, more specifically so-called “furnace” carbon blacks.

[0078] Among carbon blacks having a CTAB specific surface area greater than or equal to 90 m2 / g, special mention will be made of reinforcing carbon blacks of the 100 and 200 series, such as NI 15, N134 and N234 blacks (ASTM grades D-1765-2017).

[0079] Carbon blacks can be used in isolation, as commercially available, or in any other form, for example as a carrier for certain rubber additives used. Carbon blacks could, for example, already be incorporated into the diene elastomer, particularly isoprene, in the form of a masterbatch (see, for example, applications WO 97 / 36724-A2 or WO 99 / 16600-A1). Reinforcing inorganic filler

[0080] The term "reinforcing inorganic filler" here refers to any inorganic or mineral filler, regardless of its color or origin (natural or synthetic), also called "white" filler, "light" filler, or even "non-black" filler (as opposed to carbon black), capable of reinforcing, on its own and without any other means than an intermediate coupling agent, a rubber composition intended for the manufacture of tires. As is known, certain reinforcing inorganic fillers can be characterized, in particular, by the presence of hydroxyl groups (-OH) on their surface.

[0081] Suitable inorganic reinforcing fillers include mineral fillers of the siliceous type, preferably silica (SiO2), or of the aluminous type, in particular alumina (Al2O3). The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or fumed silica having a specific surface area BET and a specific surface area CTAB. two less than 450 m2 / g, preferably within a range of 30 to 400 m2 / g, in particular 60 to 300 m2 / g.

[0082] Any type of precipitated silica can be used, in particular 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 WO 03 / 016215-A1 and WO 03 / 016387-A1. Among the commercial HDS silicas, one can notably use the “Ulsil ® 5000GR”, “Ulsil ® 7000GR” silicas from the company Evonik, the “Zeosil ® 1085GR”, “Zeosil® 1115 MP”, “Zeosil® 1165MP”, “Zeosil® Premium 200MP”, “Zeosil® HRS 1200 MP” silicas from the Solvay Company.As non-HDS silica, the following commercial silicas may be used: “Ultrasil® VN2GR”, “Ultrasil® VN3GR” from Evonik, “Zeosil® 175GR” from Solvay, “Hi-Sil EZ120G(-D)”, “Hi-Sil EZ160G(-D)”, “Hi-Sil EZ200G(-D)”, “Hi-Sil 243LD”, “Hi-Sil 210”, “Hi-Sil HDP 320G” from PPG.

[0083] The specific surface area BET of silica is determined in a known manner by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" Vol. 60, page 309, February 1938, more specifically according to French standard NF ISO 9277 of December 1996 (multipoint volumetric method (5 points) - gas: nitrogen - degassing: 1 hour at 160°C - relative pressure range w / in: 0.05 to 0.17). The specific surface area CT AB of silica is determined according to French standard NF T 45-007 of November 1987 (method B).

[0084] Other examples of inorganic fillers that may be used in compositions may also be cited 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-Al, WO 02 / 053634-A1, WO 2004 / 003067-A1, WO 2004 / 056915-A2, US 6 610 261-B1 and US 6 747 087-B2. Examples include the aluminas “Baikalox A125” 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 is in the form of powder, microbeads, granules, or spheres, or any other suitable densified form. Of course, the term "reinforcing inorganic filler" also includes 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 coated with an inorganic layer such as silica, or has functional sites on its surface, particularly hydroxyl sites, requiring the use of a coupling agent to establish the bond between this reinforcing filler and the diene elastomer. Examples include carbon blacks partially or fully coated with silica, or carbon blacks modified with silica, such as, but not limited to, the "Ecoblack®" fillers of the CRX2000 series or the "CRX4000" series from Cabot Corporation.

[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 coupling agent (or bonding agent) that is at least bifunctional can be used in a well-known manner to ensure sufficient chemical and / or physical connection between the inorganic filler (surface of its particles) and the diene elastomer. Organosilanes or polyorganosiloxanes that are at least bifunctional are used in particular. "Bifunctional" means a compound having 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 including a silicon atom, said first functional group being capable of interacting with the hydroxyl groups of an inorganic charge, and a second functional group including a sulfur atom, said second functional group being capable of interacting with the diene elastomer.

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

[0091] 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 more 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 a range of 6% to 17%, and preferably 8% to 15%. This percentage can easily be adjusted by those skilled in the art according to the percentage of inorganic filler used in the composition.

[0092] The composition may also contain, in addition to coupling agents, coupling activators, inorganic filler covering agents or more generally processing aids which, by improving the dispersion of the filler in the rubber matrix and lowering the viscosity of the compositions, can improve 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,co-dihydroxy-polyorganosiloxanes (in particular α,co-dihydroxy-polydimethylsiloxanes), fatty acids such as stearic acid. Crosslinking system

[0093] The composition useful within the framework of the invention comprises a crosslinking system.

[0094] The crosslinking system can be any type of system known to those skilled in the art in the field of tire rubber compositions. In particular, it can be based on sulfur, and / or peroxide, and / or bismaleimides.

[0095] Preferably, the crosslinking system is sulfur-based; this is then referred to as a vulcanization system. The sulfur can be supplied in any form, particularly as molecular sulfur or as a sulfur-donating agent. At least one vulcanization accelerator is also preferably present, and, optionally and also preferably, various known vulcanization activators such as zinc oxide, stearic acid or equivalent compounds such as stearic acid salts and transition metal salts, guanidine derivatives (in particular diphenylguanidine), or known vulcanization retardants may be used.

[0096] Sulfur is used at a preferential rate of between 0.5 and 10 parts per annum, in particular between 1 and 5 parts per annum. The vulcanization accelerator is used at a preferential rate of between 0.5 and 10 parts per annum, more preferably between 0.5 and 5.0 parts per annum.

[0097] Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur can be used as an accelerator, in particular accelerators of the thiazole type and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. Examples of such accelerators include the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-ter-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds. Common additives and implementation agents

[0098] The composition useful within the scope 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 tire rubber compositions, particularly in compositions intended for the manufacture of outer sidewalls of tires, such as plasticizers (such as plasticizing oils and / or plasticizing resins with or without a tackifying character), non-reinforcing fillers, pigments, 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).

[0099] In certain embodiments, the composition useful within the scope of the invention comprises a plasticizer. The plasticizer content is then greater than 0 and less than or equal to 10 parts per liter, for example from 1 to 5 parts per liter.

[0100] The plasticizer is preferably chosen from hydrocarbon resins, plasticizing oils, and mixtures thereof.

[0101] Particularly suitable are plasticizing oils selected from the group consisting of naphthenic oils (low or high viscosity, in particular hydrogenated or non-hydrogenated), paraffinic oils, MES (Medium Extracted Solvates) oils, TDAE (Treated Distillate Aromatic Extracts) oils, RAE (Residual Aromatic Extract oils), TRAE (Treated Residual Aromatic Extract) oils and SRAE (Safety Residual Aromatic Extract oils), mineral oils, vegetable oils, ether plasticizers, ester plasticizers, phosphate plasticizers, sulfonate plasticizers and mixtures of these compounds.

[0102] Hydrocarbon resins, also called hydrocarbon plasticizing resins, are polymers well known to those skilled in the art, essentially based on carbon and hydrogen but which may contain other types of atoms, for example oxygen, usable in particular as plasticizing or tackifying agents in polymer matrices. They are by nature at least partially miscible (i.e., compatible) at the ratios used with the polymer compositions for which they are intended, so as to act as true diluents. They were described, for example, in the book entitled "Hydrocarbon Resins" by R. Mildenberg, M. Zander, and G. Collin (New York, VCH, 1997, ISBN 3-527-28617-9), Chapter 5 of which is devoted to their applications, particularly in pneumatic rubber (5.5. "Rubber Tires and Mechanical Goods"). As is known, these hydrocarbon resins can also be classified as thermoplastic resins in that they soften upon heating and can thus be molded.

[0103] The softening point of hydrocarbon resins is measured according to ISO 4625 (Ring and Bail method). The Tg is measured according to ASTM D3418 (1999). The macrostructure (Mw, Mn and Ip) of the hydrocarbon resin is determined by size exclusion chromatography (SEC): tetrahydrofuran solvent; temperature 35°C; concentration 1 g / l; flow rate 1 ml / min; solution filtered on 0.45 pm porosity filter before injection; Moore calibration with polystyrene standards; set of 3 "WATERS" columns in series ("STYRAGEL" HR4E, HR1 and HR0.5); detection by differential refractometer ("WATERS 2410") and its associated operating software ("WATERS EMPOWER").

[0104] Hydrocarbon resins can be aliphatic, aromatic, or of the aliphatic / aromatic type, i.e., based on aliphatic and / or aromatic monomers. They can be natural or synthetic, petroleum-based or not (if so, also known as petroleum resins).

[0105] Suitable aromatic monomers include, for example, styrene, alpha-methylstyrene, indene, ortho-, meta-, para-methylstyrene, vinyl-toluene, para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, and any vinylaromatic monomer derived from a C9 cut (or more generally from a C8 to C10 cut). Preferably, the vinylaromatic monomer is styrene or a vinylaromatic monomer derived from a C9 cut (or more generally from a C8 to C10 cut). Preferably, the vinylaromatic monomer is the minor monomer, expressed as a mole fraction, in the copolymer under consideration.

[0106] According to a particularly preferred embodiment, the hydrocarbon plasticizing resin is chosen from the group consisting of cyclopentadiene (abbreviated CPD) or dicyclopentadiene (abbreviated DCPD) homopolymer or copolymer resins, terpene homopolymer or copolymer resins, terpene phenol homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins, C9-cut homopolymer or copolymer resins, Alpha-methyl-styrene homopolymer and copolymer resins and mixtures of these resins.

[0107] The term "terpene" here encompasses, as is known, the monomers alpha-pinene, beta-pinene, and limonene; the monomer limonene is known to exist in the form of three possible isomers: L-limonene (levorotatory enantiomer), D-limonene (dextrorotatory enantiomer), or dipentene, a racemic compound of the dextrorotatory and levorotatory enantiomers. Among the hydrocarbon plasticizing resins mentioned above, we will cite in particular resins of homo- or copolymers of alpha-pinene, beta-pinene, dipentene, or polylimonene.

[0108] As is known, high Tg hydrocarbon resins are thermoplastic hydrocarbon resins, whose Tg is greater than 20°C.

[0109] Preferably, the plasticizing resin is a high Tg hydrocarbon plasticizing resin having at least one of the following characteristics: - a Tg greater than 30°C; - an average number molecular mass (Mn) between 300 and 2000 g / mol, more preferably between 400 and 1500 g / mol; - a polymolecularity index (Ip) less than 3, more preferably less than 2 (reminder: Ip = Mw / Mn with Mw average molecular mass by weight).

[0110] More preferably, this high Tg hydrocarbon plasticizing resin exhibits all the above preferred characteristics.

[0111] The above-mentioned preferred high Tg hydrocarbon resins are well known to those skilled in the art and are commercially available, for example sold with regard to: - polylimonene resins: by the company DRT under the name "Dercolyte L120" (Mn=625 g / mol; Mw=1010 g / mol; Ip=l.6; Tg=72°C) or by the company ARIZONA under the name "Sylvagum TR7125C" (Mn=630 g / mol; Mw=950 g / mol; Ip=l.5; Tg=70°C); - C5 / vinylaromatic copolymer resins, in particular C5 / styrene or C5 / C9: by Neville Chemical Company under the names "Super Nevtac 78", "Super Nevtac 85" or "Super Nevtac 99", by Goodyear Chemicals under the name "Wingtack Extra", by Kolon under the names "Hikorez T1095" and "Hikorez Tl 100", by Exxon under the names "Escorez 2101" and "Escorez 1273"; - Limonene / styrene copolymer resins: by DRT under the name "Dercolyte TS 105" of the DRT company, by ARIZONA Chemical Company under the names "ZT115LT" and "ZT5100".

[0112] As examples of other preferred resins, phenol-modified alpha-methylstyrene resins may also be mentioned. To characterize these phenol-modified resins, it should be noted that a known index called the "hydroxyl value" (measured according to ISO 4326 and expressed in mg KOH / g) is used. Alpha-methylstyrene resins, particularly phenol-modified ones, are well known to those skilled in the art and are commercially available, for example, sold by Arizona Chemical under the names "Sylvares SA 100" (Mn = 660 g / mol; Ip = 1.5; Tg = 53°C); "Sylvares SA 120" (Mn = 1030 g / mol; Ip = 1.9; Tg = 64°C); "Sylvares 540" (Mn = 620 g / mol; Ip = 1.3; Tg = 36°C; hydroxyl number = 56 mg KOH / g); "Sylvares 600" (Mn = 850 g / mol; Ip = 1.4; Tg = 50°C; hydroxyl number = 31 mg KOH / g).

[0113] We can also mention resins from the alkyl-phenol family such as octylphenyl formaldehyde (OPF) available for example under the name "SP 1068" from the company SI Group as well as rosin resins such as supplied for example by the company Costa Irmaos. Composition manufacturing

[0114] The rubber composition useful within the scope of the invention is manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art: - 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, including the elastomeric matrix, fillers, and any other miscellaneous additives, with the exception of the crosslinking system, are introduced into a suitable mixer such as a standard internal mixer (for example, of the 'Banbury' type). The incorporation of the filler into the elastomer can be carried out in one or more stages by thermomechanical mixing.In the case where the filler is already incorporated in whole or in part into the elastomer in the form of a masterbatch, as described for example in applications WO 97 / 36724 or WO 99 / 16600, it is the masterbatch which is directly mixed and where appropriate the other elastomers or fillers present in the composition which are not in the form of a masterbatch, as well as any other miscellaneous additives other than the crosslinking system, are incorporated.

[0115] The non-productive phase is carried out at high temperature, up to a maximum temperature between 130°C and 170°C, for a duration generally between 2 and 10 minutes. - a second phase of mechanical work (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 110°C, for example between 40°C and 100°C, the crosslinking system is then incorporated, and the whole is then mixed for a few minutes, for example between 1 and 30 minutes.

[0116] The final composition thus obtained is then calendered, for example in the form of a sheet or plate, in particular for characterization in the laboratory, or extruded in the form of a semi-finished (or profile) of rubber usable, for example, as an inner layer in a tire.

[0117] The composition can be either in the raw state (before crosslinking or vulcanization), or in the cooked state (after crosslinking or vulcanization), can be a semi-finished product that can be used in a tire.

[0118] The crosslinking of the composition can be carried out in a manner known to those skilled in the art, for example at a temperature between 130°C and 200°C, preferably under pressure, for a sufficient time which can vary for example between 5 and 90 min.

[0119] The following examples are given for illustrative purposes only, but should in no way be considered as limiting the present invention. TIRES

[0120] The tire according to the invention is intended for use on passenger vehicles, SUVs ("Sport Utility Vehicles"), two-wheeled vehicles (particularly motorcycles), aircraft, or industrial vehicles selected from among vans, "Heavy Goods Vehicles"—that is, subways, buses, road transport vehicles (trucks, tractors, trailers), off-road vehicles such as agricultural or construction equipment—and others. Preferably, the tire according to the invention is particularly suitable for use on passenger vehicles, vans, and SUVs.

[0121] The following examples are given for illustrative purposes only. They should in no way be considered as limiting the present invention. EXAMPLES Dynamic properties:

[0122] The dynamic properties, in particular G* 10% return at 60°C and G” 10% return at 60°C, representing respectively the stiffness and the hysteresis, 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 of 4 mm thickness and of 400 mm2 of cross-section) is recorded, subjected to a sinusoidal loading in simple alternating shear, at the frequency 1OHz, at a temperature of 60°C.

[0123] For the measurements of the complex dynamic shear modulus (G*) and the loss factor (G”), 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 observed value of G” 10% is indicated, as well as the modulus G* at 10% strain, denoted G* 10%.

[0124] The results are expressed on a basis of 100 relative to the control (the value of 100 is given to the control). Traction Tests:

[0125] These tensile tests allow the determination of elastic stresses and fracture properties. Unless otherwise specified, they are carried out in accordance with French standard NF T 46-002.

[0126] Processing tensile recordings makes it possible, in particular, to plot the modulus curve as a function of elongation. The modulus used here is the nominal (or apparent) secant modulus measured at the first elongation, calculated by referring to the initial cross-section of the specimen. The nominal secant modulus (or apparent stress, in MPa) is measured at the first elongation at 10% and 300% elongation, denoted MSA10 and MSA300 respectively.

[0127] We also measure the deformations at break and the tearability break energy at 23°C. at 100°C+ / -2°C, according to standard NFT 46-002, on samples baked for 50 min at 140°C.

[0128] The results are expressed on a basis of 100 relative to the control (the value of 100 is given to the control). Tearability

[0129] Tensile tests allow the determination of the moduli of elasticity and the breaking properties and are based on the NF ISO 37 standard of December 2005.

[0130] Tear resistance indices are measured at 23°C. Specifically, the force required to achieve fracture (in N / mm) is determined, and the strain at fracture (in %) is measured on a 10 x 85 x 2.5 mm specimen notched along its length with three notches to a depth of 5 mm, to induce fracture. The energy required to fracture the specimen, which is the product of the fracture force and the strain at fracture, can thus be determined. The results are given on a scale of 100, meaning that the values ​​are expressed relative to a reference value, the measured value of which is considered the standard at 100.

[0131] Thus, a lower value for the energy at rupture represents a decrease in tear resistance performance (i.e., a decrease in the energy at rupture), while a higher value represents better performance. Swelling index

[0132] The swelling index is determined using a rheometer, RHEOGRAPH 75, equipped with a camera system (i2S Company, reference 21400328).

[0133] The rheometer consists of two identical (20 mm diameter) parallel cuvettes. The cuvettes are heated to the test temperature. Only one cuvette is used for the swelling measurement (sleeve number 1).

[0134] The mixture to be tested is placed inside the tank, where it is compressed by a piston that forces the mixture to exit through the die (mixture extrusion) located at the bottom of the tank. The length, diameter, and surface finish of the two dies are known. The piston moves at different speed levels predefined by the user. The pressure is measured throughout the acquisition process in order to calculate the rheological characteristics of the material.

[0135] The measurement result is the result of a single measurement. The result obtained is a swelling index (unitless number) for each speed level.

[0136] [Math.3] Swelling Index =

[0137] The results are expressed on a basis of 100 relative to the control (the value of 100 is given to the control). Preparation of rubber compounds:

[0138] The compositions are manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art: a first thermo-mechanical working or mixing phase (sometimes referred to as the "non-productive" phase) at high temperature, up to a maximum temperature between 110°C and 200°C, preferably between 130°C and 180°C, followed by a second mechanical working phase (sometimes referred to as the "productive" phase) at a lower temperature, typically below 110°C, for example between 60°C and 100°C, a finishing phase during which the crosslinking or vulcanizing system is classically incorporated; Such phases have been described for example in applications EP-A-0501227, EP-A-0735088, EP-A-0810258, WO 00 / 05300 or WO 00 / 05301.

[0139] The compositions are cooked at 140°C for 50 minutes. Tests

[0140] Tests were carried out with different rubber compositions shown in Table 1.

[0141] The formulations of the prepared compositions are described in Table 1 (components and content - unless otherwise indicated, contents are expressed in pc).

[0142] [Tables 1] T Cl C2 INV Natural Rubber 50.00 50.00 50.00 50.00 Polybutadiene 50.00 50.00 50.00 50.00 Carbon Black Grade ASTM N234 33.50 3.00 3.00 3.00 Pyrolysis Carbon Black (2) 16.25 Silica (3) 10.00 33.00 51.50 33.00 Antioxidant (4) 8.90 8.90 8.90 8.90 Ozone-Resistant Wax 1.34 1.34 1.34 1.34 Sunflower Oil 11.50 11.50 11.50 11.50 Zinc Oxide (5) 2.50 2.50 2.50 2.50 Stearic acid (6) 1.00 1.00 1.00 1.00 Liquid silane Si69 0.50 3.30 3.30 3.30 Accelerator (7) 0.90 0.90 0.90 0.90 Sulfur 1.80 1.80 1.80 1.80 Activator (8) - 0.33 0.33 0.33

[0143] Table 1: Composition formulations

[0144] (1) WTR80-0 marketed by Leghih Technologies

[0145] (2) P550 marketed by Scandinavian Enviro Systems (ash (%)): 18.5; sulfur (%): 3; zinc (%): 4.5; STSA specific surface area: 56 m² / g (ASTM D6556-2021); void volume at 50 MPa: 44 ml / 100 g (ASTM D7854-21)

[0146] (3) Ultrasil ® 7000GR” marketed by the company EVONIK

[0147] (4) Combination of two TMQ antioxidants ((N-(l,3-dimethylbutyl)-N-phenyl- para-phenylenediamine (“Santoflex 6-PPD” from Flexsys) and 2,2,4-trimethyl-l,2-dihydroquinolone (“TMQ” from Lanxess)

[0148] (5) Zinc oxide (industrial grade) marketed by Unicore

[0149] (6) Stearine marketed by the company Unigema under the name " Pristerene 4931 "

[0150] (7) N-cyclohexyl-2-Benzothiazyl-sulfenamide marketed by Flexsy under the name 'Santocunre CBS'

[0151] (8) Diphenylguanidine “Perkacit DPG” from Flexsys

[0152] The properties of the compositions measured when cooked are presented in Table 2.

[0153] [Tables2] T Cl C2 INV % volumetric expressed relative to the total volume of the composition Silica 3 10 15 10 N234 12 1 1 1 Other fillers - - - 5 TOTAL 15 11 16 16 Deformation at break base 100 100 91 102 100 Tearability at break energy 23 °C base 100 100 43 188 151 G” 10% return base 100 100 56 163 105 IG 80s-l base 100 100 136 129 121

[0154] Table 2: Properties of the compositions

[0155] Tests have shown that a decrease in the reinforcing filler content in a rubber composition leads to compositions exhibiting hysteresis gains (T and Cl compositions). However, this hysteresis gain is accompanied by a decrease in tear energy and a degradation of the processability of the compositions (IG 80s-1). Indeed, the swelling of the compositions reaches levels that make them less efficient for use in commonly employed industrial equipment.

[0156] By comparing the Cl and C2 compositions, it can be observed that an increase in the total volume of the charge reduces swelling. However, this effect is accompanied by a degradation of rolling resistance performance (10% increase in G-force).

[0157] Surprisingly, it has been observed that, at the same total charge volume (comparison of C2 and INV compositions), the partial substitution of silica by pyrolysis carbon black allows a good compromise between performance and processability to be achieved.

Claims

Demands

1. A tire having an outer sidewall, the outer sidewall comprising at least one rubber composition based on: - at least one elastomer; - 16 to 20% by volume, relative to the total volume of the composition, of reinforcing fillers; and - a crosslinking system; the reinforcing fillers comprising: - from 6 to 16%, preferably from 6 to 11%, by volume, relative to the total volume of the composition, of reinforcing fillers selected from the group consisting of inorganic reinforcing fillers, carbon blacks having a specific surface area CT AB greater than or equal to 90 m2 / g and mixtures of inorganic reinforcing fillers and carbon blacks having a specific surface area CTAB greater than or equal to 90 m2 / g in which the inorganic reinforcing filler is predominant by mass, the specific surface area being measured according to standard NF T 45-007 of November 1987, method B;- sufficient quantities of pyrolysis carbon blacks to achieve a volume of reinforcing fillers in the composition ranging from 16% to 20% relative to the total volume of the composition.

2. Pneumatic according to claim 1, wherein the or each elastomer is a diene elastomer selected from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers.

3. Pneumatic according to claim 1 or 2, wherein the rubber composition comprises from 25 to 100 parts natural rubber and from 0 to 75 parts at least one polybutadiene.

4. Pneumatic according to claim 3, wherein the rubber composition comprises 50 parts natural rubber and 50 parts polybutadiene.

5. Tire according to any one of claims 1 to 4 wherein carbon blacks having a CTAB specific surface area greater than or equal to 90 m2 / g are selected from the reinforcing carbon blacks of the 100 and 200 series of ASTM D-1765-2017 grades.

6. Pneumatic according to any one of claims 1 to 5 wherein the reinforcing inorganic fillers are silica.

7. Pneumatic according to any one of the preceding claims, wherein the crosslinking system is a vulcanizing system based on molecular sulfur and / or a sulfur-donating agent.

8. Pneumatic according to any one of the preceding claims, wherein the vulcanizing system comprises between 0.5 and 10 parts per liter of sulfur, preferably between 1 and 5 parts per liter.

9. Pneumatic according to any one of the preceding claims, 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, the ash content being measured by calcination in platinum capsules in a muffle furnace at 825°C.

10. Pneumatic according to any one of the preceding claims, 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, the sulfur content being measured by LECO furnace.

11. Pneumatic according to any one of the preceding claims, wherein the composition further comprises one or more agents selected from the group consisting of plasticizers, non-reinforcing fillers, pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents and reinforcing resins.