Tyre having casing side based on composition comprising pyrolytic carbon black

Abstract

The present invention relates to a pneumatic tire, more particularly to the side of the tire casing, that is, according to definition, to an elastic layer in contact with ambient air located radially on the outer side of the tire.

Description

Technical Field

[0001] The present invention relates to pneumatic tires and more particularly to the tire sidewalls, that is to say, by definition, to the elastic layer situated radially on the outside of the tire and in contact with the ambient air. Background Art

[0002] Within a tire, three areas are usually distinguished:

[0003] - a radially outer region in contact with the ambient air;

[0004] - a radially inner region in contact with the inflation gas;

[0005] -The inner area of ​​the tire.

[0006] The radially external zone in contact with the ambient air is substantially composed of the tread and the sidewalls of the tire. The sidewalls are elastomeric layers located on the outside of the carcass reinforcement with respect to the inner cavity of the tire between the crown and the beads, thus completely or partially covering the area of ​​the carcass reinforcement extending from the crown to the beads.

[0007] The radially inner region in contact with the inflation gas usually consists of a layer that is airtight to the inflation gas, sometimes called a liner.

[0008] The inner region of the tire is the region between the outer region and the inner region. This region includes layers or plies referred to herein as tire inner layers. These layers are, for example, carcass plies, tread sublayers, tire belt plies or any other layer that is not in contact with the ambient air or the inflation gas of the tire.

[0009] It is important for the performance quality of the tire that the outer sidewall area has good performance quality in terms of rolling resistance. By reducing the filler content in the rubber composition and mainly using silica, good performance quality in terms of rolling resistance can be obtained. However, it has been observed that reducing the filler content in the rubber composition can lead to processability problems of the composition, in particular uncontrolled swelling of the composition, making it unsuitable for use in industrial equipment commonly used in the manufacture of tires.

[0010] There is therefore still a need for available compositions which have both good processability and good performance qualities in the cured state, in particular with regard to rolling resistance, and which advantageously meet the ever-increasing current demands to limit the environmental impact of tyre manufacture and use. Summary of the invention

[0011] The present invention relates to a tire having sidewalls comprising at least one rubber composition based on:

[0012] - at least one elastomer;

[0013] - 16% to 20% by volume of reinforcing fillers relative to the total volume of the composition; and

[0014] - Cross-linking system;

[0015] The reinforcing filler comprises:

[0016] - 6% to 16% by volume, preferably 6% to 11% by volume, of reinforcing fillers, relative to the total volume of the composition, the reinforcing fillers being selected from reinforcing inorganic fillers, CTAB with a specific surface area greater than or equal to 90 m 2 / g of carbon black, and the specific surface area of ​​the reinforcing inorganic filler and CTAB is greater than or equal to 90m 2 / g of carbon black, wherein the reinforcing inorganic filler accounts for the main mass;

[0017] - Pyrolytic carbon black in an amount sufficient to bring the volume of reinforcing filler in the composition to 16% to 20% relative to the total volume of the composition.

[0018] Other aspects of the invention are described below and in the claims.

[0019] definition

[0020] The expression "composition based on" is understood to mean that the composition comprises a mixture and / or in situ reaction products of the various components used, some of which are able and / or intended to react at least partially with one another during the various stages of the manufacture of the composition; the composition can thus be in a completely or partially crosslinked state or in a non-crosslinked state.

[0021] For the purposes of the present invention, the expression “parts by weight per 100 parts by weight of elastomer” (or phr) is understood to mean parts by mass per 100 parts by mass of elastomer or rubber, the two terms being synonymous.

[0022] Herein, unless otherwise expressly stated, all percentages (%) shown are mass percentages (%).

[0023] For the purposes of the present invention, the term "predominant" means that the compound is predominant among the compounds of the same type in the composition, that is, it is the one that represents the largest amount by mass among the compounds of the same type. In other words, the mass of the 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 only one elastomer, the elastomer is predominant within the meaning of the present invention, whereas in a system comprising two elastomers, the predominant elastomer represents more than half of the mass of the total elastomer, in other words, the mass of the elastomer represents at least 51% of the mass of the total elastomer. In the same way, a "predominant" filler is the filler that represents the largest mass among the fillers of the composition. In other words, the mass of the filler represents at least 51% of the mass of the total fillers in the composition.

[0024] In addition, any numerical interval represented by the expression "between a and b" represents a numerical range extending from greater than a to less than b (i.e., excluding the end values ​​a and b), while any numerical interval represented by the expression "a to b" means a numerical range extending from a to b (i.e., including the strict end values ​​a and b). Herein, when a numerical interval is described as the expression "a to b", it is also preferred to explain that the interval can be represented by the expression "between a and b".

[0025] The expression "radial" refers to the radius of the tire. In this sense, a point P1 is said to be "radially inside" a point P2 (or "radially on the inside of" a 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 on the outside of" a point P4) if it is further away from the axis of rotation of the tire than point P4. A movement is said to be "radially inwards (or outwards)" when the direction of the movement is the shorter (or longer) radius. This meaning of the term also applies when radial distances are concerned.

[0026] The term "radial cross section" or "radial section" is understood here to be a cross section or section along a plane containing the axis of rotation of the tire.

[0027] The "axial" direction is the direction parallel to the axis of rotation of the tire. Point P5 is said to be "axially inside" (or "axially on the inside of point P6") of point P6 if point P5 is closer to the mid-plane of the tire than point P6. Conversely, point P7 is said to be "axially outside" (or "axially on the outside of point P8") of point P8 if point P7 is further away from the mid-plane of the tire than point P8. The "mid-plane" of the tire is the plane perpendicular to the axis of rotation of the tire and equidistant from the annular reinforcing structure of each bead.

[0028] A "circumferential" direction is a direction perpendicular to both the radius and the axial direction of the tire.

[0029] The carbon-containing compounds mentioned in this specification may be fossil-derived or bio-based compounds. In the latter case, they may be partially or completely derived from biomass, or obtained from renewable raw materials derived from biomass. This specifically relates to polymers, plasticizers, fillers, etc. DETAILED DESCRIPTION OF THE INVENTION

[0031] The inventors have developed a rubber composition that meets the above needs. It has been demonstrated that the addition of pyrolytic carbon black to a rubber composition can increase the filler content in the composition, thereby improving its processability, without compromising the performance qualities of the composition.

[0032] The present invention therefore relates to a tire having sidewalls comprising at least one rubber composition based on:

[0033] - at least one elastomer;

[0034] - 16% to 20% by volume of reinforcing fillers relative to the total volume of the composition; and

[0035] - Cross-linking system;

[0036] The reinforcing filler comprises:

[0037] - 6% to 16% by volume, preferably 6% to 11% by volume, of reinforcing fillers, relative to the total volume of the composition, the reinforcing fillers being selected from reinforcing inorganic fillers (preferably silica), CTAB with a specific surface area greater than or equal to 90 m 2 / g of carbon black, and a reinforcing inorganic filler (preferably silica) with a specific surface area of ​​CTAB greater than or equal to 90m 2 / g of carbon black, wherein the reinforcing inorganic filler (preferably silica) accounts for the main mass;

[0038] - Pyrolytic carbon black in an amount sufficient to bring the volume of reinforcing filler in the composition to 16% to 20% relative to the total volume of the composition.

[0039] The rubber composition may also contain conventional additives and processing aids.

[0040] The various components of the rubber composition can be described as follows.

[0041] Elastomer

[0042] The composition used in the context of the present invention is based on at least one elastomer (or without distinction, rubber).

[0043] The elastomer may be chosen from diene elastomers and mixtures thereof.

[0044] The term “diene elastomer”, whether natural or synthetic, is understood in a known manner to mean an elastomer composed at least partly (ie homopolymer or copolymer) of diene monomer units (monomers carrying two conjugated or non-conjugated carbon-carbon double bonds).

[0045] These diene elastomers can be divided into two categories: “essentially unsaturated” or “essentially saturated”. The term “essentially unsaturated” is generally understood to mean a diene elastomer obtained at least partly from conjugated diene monomers having a content of subunits or units of diene origin (conjugated dienes) greater than 15% (mol %); thus diene elastomers such as butyl rubber or copolymers of dienes with α-olefins of the EPDM type do not fall into the aforementioned definition but may in particular be referred to as “essentially saturated” diene elastomers (low or very low content of subunits of diene origin, always less than 15%).

[0046] The term "diene elastomer that can be used" means in particular:

[0047] (a) - any homopolymer obtained by the polymerization of conjugated or non-conjugated diene monomers having 4 to 18 carbon atoms;

[0048] (b) - Any copolymer obtained by copolymerization of a conjugated or nonconjugated diene having from 4 to 18 carbon atoms with at least one other monomer.

[0049] The other monomers may be ethylene, olefins or conjugated or non-conjugated dienes.

[0050] Suitable conjugated dienes include conjugated dienes having 4 to 12 carbon atoms, in particular 1,3-dienes, such as 1,3-butadiene and isoprene, among others.

[0051] Suitable olefins include vinyl aromatic compounds having from 8 to 20 carbon atoms and aliphatic alpha-monoolefins having from 3 to 12 carbon atoms.

[0052] Suitable vinylaromatic compounds include, for example, styrene, (o-, m- or p-)methylstyrene, the “vinyltoluene” commercial mixtures or p-(tert-butyl)styrene.

[0053] Particularly suitable aliphatic α-monoolefins are non-cyclic aliphatic α-monoolefins having 3 to 18 carbon atoms.

[0054] More specifically, the diene elastomer that can be used in the composition may be:

[0055] (a') - any homopolymer obtained by polymerizing conjugated diene monomers having 4 to 12 carbon atoms;

[0056] (b') - any copolymer obtained by copolymerizing one or more conjugated dienes with each other or with one or more vinyl aromatic compounds having 8 to 20 carbon atoms;

[0057] (c') - Any copolymer obtained by copolymerizing one or more conjugated or non-conjugated dienes with ethylene, alpha-monoolefins or mixtures thereof, for example elastomers obtained from ethylene, propylene and non-conjugated diene monomers of the abovementioned type.

[0058] Preferably, the diene elastomer is chosen from polybutadiene (BR), natural rubber (NR), synthetic polyisoprene (IR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers. The butadiene copolymers are especially chosen from butadiene-styrene copolymers (SBR).

[0059] The diene elastomer may be modified, ie coupled and / or star-branched, or functionalized, or coupled and / or star-branched and simultaneously functionalized.

[0060] Thus, the diene elastomers may be coupled and / or star-branched, for example by means of silicon or tin atoms linking the elastomer chains together.

[0061] The diene elastomer may be functionalized simultaneously or alternately and comprise at least one functional group. The term "functional group" is understood to mean a group comprising at least one heteroatom chosen from Si, N, S, O or P. Particularly suitable as functional groups are those comprising at least one function, for example: silanols, alkoxysilanes, cyclic or acyclic primary, secondary or tertiary amines, thiols or epoxides.

[0062] The rubber composition used in the context of the invention may comprise just one diene elastomer or a mixture of several diene elastomers.

[0063] In certain embodiments, the rubber composition used in the context of the present invention comprises one or more elastomers; thus, it may comprise 25 to 100 phr of natural rubber and 0 to 75 phr of at least one polybutadiene, preferably 35 to 75 phr of natural rubber and 25 to 65 phr of at least one polybutadiene.

[0064] In certain embodiments, the rubber composition used in the context of the present invention comprises a mixture of natural rubber (NR) and at least one polybutadiene (BR) as elastomer. Preferably, the mixture consists of 50 phr of natural rubber (NR) and 50 phr of polybutadiene (BR).

[0065] Reinforcement filler

[0066] The composition used in the context of the present invention comprises a reinforcing filler. The reinforcing filler represents 16% to 20% by volume of the total volume of the composition.

[0067] The term “reinforcing filler” generally denotes any type of filler known to be capable of reinforcing a rubber composition that can be used in particular for making tires, such as organic fillers, such as carbon black or pyrolytic black, or inorganic fillers, such as silica or alumina.

[0068] The composition used in the context of the present invention comprises:

[0069] - 6% to 16% by volume, preferably 6% to 11% by volume, of reinforcing fillers, relative to the total volume of the composition, the reinforcing fillers being selected from reinforcing inorganic fillers (preferably silica), CTAB with a specific surface area greater than or equal to 90 m 2 / g of carbon black, and a reinforcing inorganic filler (preferably silica) with a specific surface area of ​​CTAB greater than or equal to 90m 2 / g of carbon black, wherein the reinforcing inorganic filler (preferably silica) accounts for the main mass;

[0070] - Pyrolytic carbon black in an amount sufficient to bring the volume of reinforcing filler in the composition to 16% to 20% relative to the total volume of the composition.

[0071] In certain embodiments, the compositions used in the context of the present invention comprise:

[0072] - 6% to 16% by volume, preferably 6% to 11% by volume, of a reinforcing filler, relative to the total volume of the composition, the reinforcing filler being selected from reinforcing inorganic fillers (preferably silica), reinforcing inorganic fillers (preferably silica) and CTAB having a specific surface area greater than or equal to 90 m 2 / g of carbon black, wherein the reinforcing inorganic filler (preferably silica) accounts for the main mass;

[0073] - Pyrolytic carbon black in an amount sufficient to bring the volume of reinforcing filler in the composition to 16% to 20% relative to the total volume of the composition.

[0074] Generally, the specific surface area of ​​the inorganic filler (preferably silica) and CTAB is greater than or equal to 90 m 2 A mixture of 100 g of carbon black (in which the inorganic filler occupies a major mass) contains 10 volumes of the inorganic filler / 2 to 3 volumes of the carbon black.

[0075] The CTAB specific surface area of ​​carbon black is determined according to the standard ASTM D3765-03a published in December 2003.

[0076] The reinforcing fillers may be as follows.

[0077] Pyrolytic Carbon Black

[0078] For the purposes of the present invention, the term "pyrolytic carbon black" is understood to mean carbon black produced by a pyrolysis process of a material comprising at least a carbon-based polymer and carbon black (hereinafter referred to as the material to be pyrolyzed), for example in the case of recycling such material. The physical state of the material to be pyrolyzed provided is not important, whether it is a powder, granules, strips or any other form, in a cross-linked or non-cross-linked state.

[0079] Preferably, the material to be pyrolyzed can be recovered from the article or from products (e.g. by-products or waste) generated during its manufacture / production; these articles can be selected from pneumatic tires, non-pneumatic tires, industrial conveyor belts, transmission belts, rubber seals, rubber hoses, shoe soles and windscreen wipers. More preferably, the pyrolytic carbon black that can be used in the context of the present invention is a carbon black obtained by a pyrolysis process, wherein the material to be pyrolyzed originates from an article selected from pneumatic tires and non-pneumatic tires.

[0080] In the context of the present invention, "pyrolysis" refers to any type of thermal decomposition carried out in the absence of oxygen, the raw material of which is the material to be pyrolyzed as defined above. Thus, pyrolytic carbon black differs from "industrial" and / or "ASTM grade" carbon black in that the carbon-based raw material used for pyrolysis is a material comprising at least a carbon-based polymer and carbon black, rather than a material derived from petroleum fractions or from coal or from natural source oils.

[0081] Pyrolytic carbon blacks which can be used in the context of the present invention differ from known carbon blacks such as industrial carbon blacks, in particular "furnace" carbon blacks, in particular by their higher ash content.

[0082] Preferably, the pyrolytic carbon black useful in the context of the present invention has an ash content of 5 to 30 wt. %, more preferably 8 to 25 wt. %, more preferably 10 to 22 wt. %, relative to the total weight of the pyrolytic carbon black.

[0083] Preferably, the pyrolytic carbon black that can be used in the context of the present invention has a sulfur content of more than 2% by weight, preferably from 2.5% to 5% by weight, relative to the total weight of the pyrolytic carbon black.

[0084] Preferably, the pyrolytic carbon black which can be used in the context of the present invention has a zinc content of more than 2% by weight, preferably from 2.5% to 8% by weight, relative to the total weight of the pyrolytic carbon black.

[0085] Preferably, the pyrolytic carbon black that can be used in the context of the present invention has a carbon black content at 20 m / s measured according to standard ASTM D 6556-2021. 2 / g to 200m 2 / g, more preferably within 30m 2 / g to 90m 2 / g range of STSA specific surface area.

[0086] Preferably, the pyrolytic carbon black that can be used in the context of the present invention has a void volume ranging from 30 to 60 ml / 100 g, more preferably from 35 to 55 ml / 100 g, measured according to standard ASTM D7854-21 and at a pressure of 50 MPa.

[0087] The ash content is determined by calcination in a platinum dish in a muffle furnace at 825°C according to the following protocol. Before each series of measurements, one dish is pre-determined and tared to within 0.1 mg, the mass being denoted P0. 5 grams of the pyrolytic carbon black sample is placed in the dish and accurately weighed to within 0.1 mg; this mass is denoted P1. The dish and its contents are pre-calcined using a Bunsen burner until smoke appears and the product ignites. Once the product has been completely burned, the dish and its contents are placed in a muffle furnace heated to 825°C for 1 hour. After 1 hour, the dish is removed from the furnace and immediately placed in a desiccator at ambient temperature. When the dish and ash have returned to ambient temperature, the dish is weighed again to obtain the mass P2. Finally, the ash content (% ash) can be obtained using the following formula:

[0088]

[0089] After the sample is calcined, the ash is then absorbed into an acidic medium and measured by ICP-AES (inductively coupled plasma atomic emission spectrometry) to obtain the zinc content in the pyrolytic carbon black. The ash is obtained by executing the above protocol. Take approximately exactly 100 mg of ash (test sample) and introduce it into a PFA (perfluoroalkoxy) tube of a HotBlock heating plate. Then add 8 ml of 37% concentrated hydrochloric acid, 3 ml of 65% concentrated nitric acid and 0.5 ml of 40% hydrofluoric acid. Seal the tube with a stopper and heat at 130°C for 2 hours. After cooling, use ultrapure water to transfer the contents to a 100 ml PTFE (polytetrafluoroethylene) volumetric flask that already contains 2 grams of boric acid (for neutralizing hydrofluoric acid). Add ultrapure water until the scale line. The resulting solution was diluted 100 times by placing 1 ml of the solution into a 100 ml PFTE bottle already 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. The diluted solution was then filtered on a 0.45 μm GHP syringe filter and then analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Prior to analyzing the diluted solution, at least 5 standards were analyzed by ICP-AES at 0, 0.5, 1, 2 and 5 mg / L zinc concentrations. These standards were prepared by diluting a commercial solution with a certified zinc concentration of 1 g / L using a 100 ml volumetric flask.

[0090] These volumetric flasks already contain 8 ml of 37% concentrated hydrochloric acid, 3 ml of 65% concentrated nitric acid, 0.5 ml of 40% hydrofluoric acid and 2 g of boric acid. The standard solutions are analyzed by ICP-AES (at wavelength λZn=202.613 nm). For each standard concentration (c), the intensity of the zinc signal IZn is plotted on the graph IZn=f(c), which corresponds to the calibration curve (type y=ax+b). Sample solutions of unknown concentration (diluted solutions) are then measured under the same conditions as the standards. The measured intensities are linked to the concentrations by means of the previously obtained calibration curve. Since the test sample and volume have been recorded in advance, the ash concentration [c] expressed in mass % is obtained directly by the software. The concentration of zinc in pyrolytic carbon black expressed in mass % [c] is obtained by the following formula: 炭黑 :

[0091] [c] 炭黑 =[c] 灰分 *1009*% ash

[0092] The sulfur content of pyrolytic carbon black is determined using a LECO furnace. The LECO sulfur analyzer is designed to specifically measure the sulfur content of organic and / or inorganic materials by combustion and non-dispersive infrared detection. Before measuring the sulfur content in a sample, the boat is cleaned and the furnace is calibrated. The boat of the LECO furnace has been cleaned beforehand: this involves analyzing an empty boat under the same conditions as the sample. The calibration curve is drawn using a commercial standard called "BBOT" which has a purity greater than 99.99% and a guaranteed content of carbon (C), hydrogen (H), nitrogen (N), oxygen (O), and sulfur (S). The contents are as follows: C%: 72.52; H%: 6.09; N%: 6.51; O%: 7.43 and S%: 7.44. Approximately exactly 10±3, 20±3, and 40±3 mg of BBOT are weighed into the boat. The standard / boat assembly is placed in the combustion furnace and adjusted to 1350°C under pure oxygen. The combination of furnace temperature and analysis flow rate causes combustion of the sample and releases sulfur and / or carbon in the form of SO2(g). After a period of 20 seconds, oxygen begins to flow through the torch to accelerate the combustion of the flame-retardant material. Sulfur and / or carbon are entrained by the oxygen flow through the infrared detection chamber in the form of SO2(g). The instrument software plots a curve that relates the introduced standard mass to the response (area) observed on the detector. This results in a calibration curve. After careful cleaning of the sampling equipment, approximately exactly 80 ± 5 mg of pyrolytic carbon black is weighed out and placed in the boat of the LECO furnace. The observed area of ​​the SO2 peak is related to the concentration via the calibration curve. The instrument software then uses the mass of the sample placed in the boat to calculate the mass % of sulfur in the sample.

[0093] For example, thermal carbon black is sold by BlackBear under the reference BBCT30 or by Scandinavian Enviro Systems under the reference P550.

[0094] Carbon Black

[0095] Suitable carbon blacks include all carbon blacks, in particular the carbon blacks customarily used in tires or their treads, especially industrial carbon blacks, more particularly "furnace" blacks.

[0096] The specific surface area of ​​CTAB is greater than or equal to 90m 2 Among the carbon blacks of 100 and 200 series, mention will be made more specifically of reinforcing carbon blacks such as, for example, N115, N134 and N234 carbon blacks (ASTM D-1765-2017 grades).

[0097] Carbon black can be used in the single state as commercially available, or in any other form, for example as a carrier for some of the rubber additives used. Carbon black may, for example, have been introduced into diene elastomers, in particular isoprene elastomers, in the form of masterbatches (see, for example, patent applications WO 97 / 36724-A2 and WO 99 / 16600-A1).

[0098] Reinforced inorganic fillers

[0099] The term "reinforcing inorganic filler" is understood herein to mean any inorganic or mineral filler, whatever its color and its origin (natural or synthetic), also called "white" filler, "transparent" filler or even "non-black" filler in comparison to carbon black, which is capable of reinforcing the rubber composition intended for the manufacture of tires alone without the need for means other than intermediate coupling agents. In a known manner, certain reinforcing inorganic fillers may be characterized in particular by the presence of hydroxyl (-OH) groups at their surface.

[0100] Mineral fillers of the siliceous type, preferably silicon dioxide (SiO2), or of the aluminous type, in particular aluminum oxide (Al2O3), are particularly suitable as reinforcing inorganic fillers. The silicon dioxide used may be any reinforcing silicon dioxide known to those skilled in the art, in particular one having a BET specific surface area and a CTAB specific surface area of ​​less than 450 m 2 / g, preferably 30 to 400m 2 / g, especially 60 to 300m 2 Any precipitated silica or fumed silica in the range of / g.

[0101] Any type of precipitated silica can be used, in particular highly dispersible precipitated silica (HDS, i.e. “highly dispersible silica”). These precipitated silicas, which may or may not be highly dispersible, are known to the person skilled in the art. Mention may be made, for example, of the silicas described in patent applications WO 03 / 016215-A1 and WO 03 / 016387-A1. Among the commercial HDS silicas, use may be made, in particular, of the precipitated silicas from Evonik. 5000GR and 7000GR silica or from Solvay 1085GR, 1115MP, 1165MP, Premium 200MP and HRS1200MP silica. As non-HDS silica, the following commercially available silicas can be used: VN2GR and VN3GR silica, from Solvay 175GR silica or Hi-Sil EZ120G(-D), Hi-Sil EZ160G(-D), Hi-Sil EZ200G(-D), Hi-Sil 243LD, Hi-Sil 210 and Hi-Sil HDP320G silica from PPG.

[0102] The BET specific surface area of ​​the silica is determined in a known manner by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" (Volume 60, page 309, February 1938), more particularly in accordance with the French standard NF ISO 9277 of December 1996 [multipoint (5-point) volumetric method - gas: nitrogen - degassing: 1 hour at 160°C - relative pressure p / po range: 0.05 to 0.17]. The CTAB specific surface area of ​​the silica is determined in accordance with the French standard NF T 45-007 of November 1987 (method B).

[0103] As other examples of inorganic fillers that can be used in the composition, mention may also be made of mineral fillers of the aluminum type, in particular aluminum oxide (Al2O3), aluminum oxides, aluminum hydroxide, aluminosilicates, titanium oxide, silicon carbide or silicon nitride, all reinforcing types described, for example, in patent applications WO 99 / 28376-A2, WO 00 / 73372-A1, WO 02 / 053634-A1, WO 2004 / 003067-A1, WO 2004 / 056915-A2, US 6 610 261-B1 and US 6 747 087-B2. Mention may be made in particular of the aluminum oxides Baikalox A125 or CR125 (Baikowski), APA-100RDX (Condea), Aluminoxid C (Evonik) or AKP-G015 (Sumitomo Chemicals). Although kaolin is composed mainly of aluminosilicates, it is known to those skilled in the art that kaolin is not a reinforcing filler.

[0104] It is not important in which physical state the reinforcing inorganic filler is provided, whether in the form of powder, microspheres, granules or beads or any other suitable densified form. Of course, "reinforcing inorganic filler" is also understood to mean mixtures of different reinforcing inorganic fillers, in particular mixtures of silica as described above.

[0105] A person skilled in the art will understand that it is possible to use a reinforcing filler of another nature instead of the above-mentioned reinforcing inorganic filler, provided that the reinforcing filler of another nature is covered with an inorganic layer (for example silica) or comprises on its surface functional sites (in particular hydroxyl sites) requiring the use of a coupling agent to establish a bond between the reinforcing filler and the diene elastomer. For example, mention may be made of carbon black partially or completely covered with silica, or carbon black modified with silica, such as, but not limited to, the CRX2000 series or the CRX4000 series of the company Cabot Corporation. Type of filler.

[0106] A person skilled in the art will know how to adjust the total content of reinforcing filler according to the use in question, in particular according to the type of tyre in question, for example tyres for motorcycles, passenger vehicles or utility vehicles such as vans or heavy vehicles.

[0107] In order to couple the reinforcing inorganic filler to the diene elastomer, use may be made in a known manner of at least bifunctional coupling agents (or binders) intended to provide a satisfactory chemical and / or physical connection between the inorganic filler (the surface of its particles) and the diene elastomer. In particular, use is made of at least bifunctional organosilanes or polyorganosiloxanes. The term "bifunctional" is understood to mean that the compound has a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the diene elastomer. For example, such a bifunctional compound may comprise a first functional group containing a silicon atom, the first functional group being capable of interacting with the hydroxyl groups of the inorganic filler, and a second functional group containing a sulfur atom, the second functional group being capable of interacting with the diene elastomer.

[0108] Preferably, the organosilane is chosen from organosilane polysulfides (symmetrical or asymmetrical), for example bis(3-triethoxysilylpropyl)tetrasulfide with the abbreviation TESPT, sold under the name Si69 by the company Evonik, or bis(triethoxysilylpropyl)disulfide with the abbreviation TESPD, sold under the name Si75 by the company Evonik, polyorganosiloxanes, mercaptosilanes, end-capped mercaptosilanes, for example S-[3-(triethoxysilyl)propyl]thiooctanoate, sold under the name NXT Silane by the company Momentive.

[0109] More preferably, the organosilane is an organosilane polysulfide.

[0110] Those skilled in the art can find examples of coupling agents in WO 02 / 083782, WO 02 / 30939, WO 02 / 31041, WO 2007 / 061550, WO 2006 / 125532, WO 2006 / 125533, WO 2006 / 125534, US 6849754, WO 99 / 09036, WO 2006 / 023815, WO 2007 / 098080, WO 2010 / 072685 and WO 2008 / 055986.

[0111] The content of coupling agent is preferably 0.5% to 15% by weight of the reinforcing inorganic filler, preferably 4% to 12% by weight of the reinforcing inorganic filler, more preferably 6% to 10% by weight. Usually, the content of coupling agent is less than 20phr, preferably, in the range of 6 to 17phr, preferably 8 to 15phr. This content can be easily adjusted by those skilled in the art according to the content of inorganic filler used in the composition.

[0112] In addition to the coupling agents, the composition may also contain coupling activators, agents for coating the inorganic fillers or more generally processing aids which, by improving the dispersion of the filler in the rubber matrix and reducing the viscosity of the composition, can improve the processability of the composition in the unprocessed state in a known manner, for example hydrolyzable silanes, such as alkylalkoxysilanes (especially alkyltriethoxysilanes), polyols, polyethers (for example polyethylene glycol), primary, secondary or tertiary amines (for example trialkanolamines), hydroxylated or hydrolyzable POS, for example α,ω-dihydroxypolyorganosiloxanes (especially α,ω-dihydroxypolydimethylsiloxane), or fatty acids, for example stearic acid.

[0113] Cross-linking system

[0114] The composition used in the context of the present invention comprises a crosslinking system.

[0115] The crosslinking system may be any type of system known to those skilled in the art in the field of tire rubber compositions. It may be based in particular on sulphur and / or peroxides and / or bismaleimides.

[0116] Preferably, the crosslinking system is based on sulfur; it is then called a vulcanization system. The sulfur can be provided in any form, in particular in the form of molecular sulfur or a sulfur donor. It is also preferred that at least one vulcanization accelerator is present, and optionally, various known vulcanization activators can also be used, such as zinc oxide, stearic acid or equivalent compounds (such as stearates), salts of transition metals, guanidine derivatives (especially diphenylguanidine), or known vulcanization retarders.

[0117] Sulfur is preferably used in an amount between 0.5 and 10 phr, in particular between 1 and 5 phr. Vulcanization accelerators are preferably used in an amount between 0.5 and 10 phr, more preferably between 0.5 and 5.0 phr.

[0118] As accelerator, use may be made of any compound capable of acting as an accelerator for the vulcanization of diene elastomers in the presence of sulfur, in particular accelerators of the thiazole type and derivatives thereof, or accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate type. As examples of such accelerators, mention may be made of the following compounds: 2-mercaptobenzothiazole disulfide (abbreviated to MBTS), N-cyclohexyl-2-benzothiazolesulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazolesulfenamide (DCBS), N-(tert-butyl)-2-benzothiazolesulfenamide (TBBS), N-(tert-butyl)-2-benzothiazolesulfenimide (TBSI), tetrabenzylthiuram disulfide (TBZTD), zinc dibenzyldithiocarbamate (ZBEC) and mixtures of these compounds.

[0119] Commonly used additives and processing aids

[0120] The composition used in the context of the present invention may also contain all or part of the customary additives and processing aids known to a person skilled in the art and which are usually used in tire rubber compositions, in particular in compositions intended for the manufacture of tire sidewalls, such as plasticizers (for example plasticizing oils and / or plasticizing resins with or without tackifying properties), non-reinforcing fillers, pigments, protective agents (for example anti-ozone waxes), chemical antiozonants, antioxidants, anti-fatigue agents, reinforcing resins (for example as described in application WO 02 / 10269).

[0121] In certain embodiments, the composition used in the context of the present invention comprises a plasticizer. The content of the plasticizer is greater than 0 phr and less than or equal to 10 phr, such as 1 phr to 5 phr.

[0122] The plasticizer is preferably selected from hydrocarbon resins, plasticizing oils and mixtures thereof.

[0123] Plasticizing oils selected from the group consisting of naphthenic oils (high or low viscosity, in particular hydrogenated or non-hydrogenated), paraffin oils, MES (medium extracted solvate) oils, TDAE (treated distilled aromatic extract) oils, RAE (residual aromatic extract) oils, TRAE (treated residual aromatic extract) oils, SRAE (safe residual aromatic extract) oils, mineral oils, vegetable oils, ether plasticizers, ester plasticizers, phosphate plasticizers, sulfonate plasticizers and mixtures of these compounds are particularly suitable.

[0124] Hydrocarbon resin, also referred to as hydrocarbon plasticizing resin, is a polymer well known to those skilled in the art, based on carbon and hydrogen, but can include other types of atoms, such as oxygen, and can be used as a plasticizer or tackifier in a polymer matrix in particular. They are at least partially miscible (i.e. compatible) with the polymer composition they are intended to be used for in terms of properties under used content, thereby serving as a real diluent. They are described in the book (New York, VCH, 1997, ISBN 3-527-28617-9) entitled " Hydrocarbon Resins " of, for example, R.Mildenberg, M.Zander and G.Collin, the 5th chapter of the book relates to their application, particularly in the application (5.5. " Rubber Tires and Mechanical Goods ") in the field of tire rubber engineering. In a known manner, in terms of the meaning that hydrocarbon resin softens when heated and can therefore be molded, these hydrocarbon resins can also be referred to as thermoplastic resins.

[0125] The softening point of hydrocarbon resins was measured according to standard ISO 4625 ("Ring and Ball" method). Tg was measured according to standard ASTM D3418 (1999). The macrostructure of hydrocarbon resins (Mw, Mn and PDI) was determined by size exclusion chromatography (SEC): solvent tetrahydrofuran; temperature 35°C; concentration 1 g / l; flow rate 1 ml / min; before injection, the solution was filtered through a filter with a porosity of 0.45 μm; molar calibration with polystyrene standards; a 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).

[0126] Hydrocarbon resins may be of aliphatic, aromatic or aliphatic / aromatic type, ie based on aliphatic and / or aromatic monomers. They may be natural or synthetic and may or may not be based on petroleum (in which case they are also called petroleum resins).

[0127] Examples of suitable aromatic monomers include styrene, alpha-methylstyrene, indene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, p-tert-butylstyrene, methoxystyrene, chlorostyrene, vinyl-mesitylene, divinylbenzene, vinylnaphthalene and any vinyl aromatic monomer derived from a C9 fraction (or more typically from a C8 to C10 fraction). Preferably, the vinyl aromatic monomer is styrene or a vinyl aromatic monomer derived from a C9 fraction (or more typically from a C8 to C10 fraction). Preferably, the vinyl aromatic monomer is a minor monomer in the copolymer under consideration, expressed as a mole fraction.

[0128] According to a particularly preferred embodiment, the hydrocarbon plasticizing resin is selected from cyclopentadiene (abbreviated as CPD) or dicyclopentadiene (abbreviated as DCPD) homopolymer or copolymer resins, terpene homopolymer or copolymer resins, terpene phenol homopolymer or copolymer resins, C5 fraction homopolymer or copolymer resins, C9 fraction homopolymer or copolymer resins, α-methylstyrene homopolymer and copolymer resins and mixtures of these resins.

[0129] The term "terpene" in this document combines in a known manner the monomers α-pinene, β-pinene and limonene, wherein the limonene monomer exists in a known manner in three possible isomeric forms: L-limonene (levorotatory enantiomer), D-limonene (dextrorotatory enantiomer) or dipentene (racemate of dextrorotatory and levorotatory enantiomers). Among the above-mentioned hydrocarbon plasticizing resins, particular mention should be made of α-pinene, β-pinene, dipentene or polylimonene homopolymer or copolymer resins.

[0130] High Tg hydrocarbon resins are known to be thermoplastic hydrocarbon resins having a Tg greater than 20°C.

[0131] Preferably, the plasticizing resin is a high Tg hydrocarbon plasticizing resin having at least any of the following characteristics:

[0132] -Tg greater than 30°C;

[0133] - a number average molecular weight (Mn) between 300 and 2000 g / mol, more preferably between 400 and 1500 g / mol;

[0134] - The polydispersity index (PDI) is less than 3, more preferably less than 2 (as a reminder: PDI = Mw / Mn, where Mw is the weight average molecular weight).

[0135] More preferably, such high Tg hydrocarbon plasticizing resins have all of the above-mentioned preferred characteristics.

[0136] The above preferred high Tg hydrocarbon resins are well known to those skilled in the art and are commercially available, for example, as sold as:

[0137] - Polylimonene resin: sold by the company DRT under the name Dercolyte L120 (Mn=625 g / mol; Mw=1010 g / mol; PDI=1.6; Tg=72° C.) or by the company Arizona under the name Sylvagum TR7125C (Mn=630 g / mol; Mw=950 g / mol; PDI=1.5; Tg=70° C.);

[0138] - C5 fraction / vinyl aromatic copolymer resins, in particular C5 fraction / styrene or C5 fraction / C9 fraction copolymer resins sold under the names Super Nevtac 78, Super Nevtac 85 or Super Nevtac 99 by Neville Chemical Company, Wingtack Extra by Goodyear Chemicals, Hikorez T1095 and Hikorez T1100 by Kolon, Escorez 2101 and Escorez 1273 by Exxon;

[0139] - Limonene / styrene copolymer resins: sold under the name Dercolyte TS105 by the company DRT, and under the names ZT115LT and ZT5100 by the Arizona Chemical Company.

[0140] As examples of other preferred resins, mention may also be made of phenol-modified alpha-methylstyrene resins. To characterize these phenol-modified resins, it should be recalled that the value known as the "hydroxyl number" (measured according to standard ISO 4326 and expressed in mg KOH / g) is used in a known manner. α-Methylstyrene resins, in particular phenol-modified α-methylstyrene resins, are known to those skilled in the art and are commercially available, for example, from Arizona Chemical under the names Sylvares SA 100 (Mn=660 g / mol; PDI=1.5; Tg=53° C.), Sylvares SA 120 (Mn=1030 g / mol; PDI=1.9; Tg=64° C.), Sylvares 540 (Mn=620 g / mol; PDI=1.3; Tg=36° C.; hydroxyl value=56 mg KOH / g), and Sylvares 600 (Mn=850 g / mol; PDI=1.4; Tg=50° C.; hydroxyl value=31 mg KOH / g).

[0141] Mention may also be made of resins of the alkylphenol family, such as octylphenylformaldehyde (OPF), available for example under the name SP 1068 from the company SI Group, and rosins, such as those supplied by the company Costa Irmaos.

[0142] Preparation of composition

[0143] The rubber composition used in the context of the present invention is manufactured in a suitable mixer using two consecutive preparation stages known to those skilled in the art:

[0144] - a first stage of thermomechanical processing or kneading ("non-preparative" stage), which can be carried out in a single thermomechanical step, during which all the necessary components, except the crosslinking system, in particular the elastomeric matrix, the filler and various other optional additives are introduced into a suitable mixer, such as a standard internal mixer (for example of the Banbury type). The filler can be introduced into the elastomer at once or in several portions while the thermomechanical kneading is in progress. If the filler has already been introduced in whole or in part into the elastomer in the form of a masterbatch (for example as described in patent applications WO 97 / 36724 or WO 99 / 16600), the masterbatch is kneaded directly and, where appropriate, the other elastomers or fillers present in the composition, not in the form of a masterbatch, as well as various other optional additives, except the crosslinking system, are introduced.

[0145] The non-productive phase is carried out at elevated temperatures up to a maximum temperature of between 130° C. and 170° C. for a period of time typically between 2 and 10 minutes.

[0146] - a second stage of mechanical processing ("preparation" stage), which is carried out in an external mixer (e.g. an open mill) after cooling the mixture obtained during the first non-preparation stage down to a relatively low temperature, typically less than 110° C., for example between 40° C. and 100° C. The crosslinking system is then introduced and the combined mixture is then mixed for a few minutes, for example between 1 and 30 minutes.

[0147] The final composition thus obtained is subsequently calendered, for example, in the form of sheets or plaques, in particular for laboratory characterizations, or extruded into the form of semi-finished (or shaped) rubber elements that can be used, for example, as inner layers of tires.

[0148] The composition may be in the raw state (before crosslinking or vulcanization) or in the cured state (after crosslinking or vulcanization), or may be a semi-finished product capable of being used in a tire.

[0149] Crosslinking of the composition can be carried out in a manner known to the person 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 minutes and 90 minutes.

[0150] The following examples are given for the purpose of illustration but should not be construed as limiting the present invention in any way.

[0151] tire

[0152] The tire according to the invention may be intended to equip motor vehicles of the passenger vehicle type, SUVs ("Sports Utility Vehicles"), or two-wheeled vehicles (in particular motorcycles), or aircraft, or industrial vehicles chosen from trucks, heavy vehicles, that is to say metros, buses, heavy road transport vehicles (trucks, tractors, trailers) or off-road vehicles (for example heavy agricultural vehicles or civil engineering vehicles), and other vehicles. Preferably, the tire according to the invention is particularly suitable for equipping vehicles of the passenger vehicle, truck and SUV type.

[0153] The following examples are given for illustration purposes only. They should not be considered as limiting the present invention in any case. DETAILED DESCRIPTION

[0154] Dynamic performance:

[0155] The dynamic properties are measured on a viscoanalyzer (Metravib VA4000) according to standard ASTM D 5992-96, in particular G*10% return at 60°C and G"10% return at 60°C, representing stiffness and hysteresis, respectively. The response is recorded on a sample of the vulcanized composition (cylindrical test piece with a thickness of 4 mm and a cross section of 400 mm2) subjected to a simple alternating sinusoidal shear stress at a frequency of 10 Hz at a temperature of 60°C.

[0156] For the measurements of the complex dynamic shear modulus (G*) and loss factor (G”), strain amplitude sweeps were performed from 0.1% to 100% peak-to-peak (outward cycle) and then from 100% to 0.1% peak-to-peak (return cycle). For the return cycle, the observed value of G” 10% and the G* modulus at 10% strain (denoted as G*10%) are shown.

[0157] The results are expressed relative to a control sample on a base 100 basis (the control sample was given a value of 100).

[0158] Tensile test:

[0159] These tensile tests enable the elastic stress and the breaking properties to be determined. Unless otherwise stated, these tests are carried out in accordance with French standard NF T 46-002.

[0160] Processing the tensile record enables specific plotting of the modulus versus elongation curve. The modulus used herein is the nominal (or apparent) secant modulus, measured in the first elongation and calculated by normalization to the initial cross section of the specimen. The nominal secant modulus (or apparent stress, in MPa) is measured in the first elongation at 10% and 300% elongation, denoted as MSA10 and MSA300, respectively.

[0161] The strain at break and the tear energy at break at 23°C, at 100°C + / - 2°C were also measured on samples cured at 140°C for 50 minutes according to standard NFT 46-002.

[0162] The results are expressed relative to a control sample with a base value of 100 (the control sample was given a value of 100).

[0163] Tearability

[0164] Tensile tests can determine the modulus of elasticity and the breaking properties and are based on the standard NF ISO37 of December 2005.

[0165] The tearability index is measured at 23°C. In particular, the force applied in N / mm to obtain the break is determined, and the strain at break is measured in % on a specimen with dimensions of 10×85×2.5 mm, with 3 cuts of 5 mm depth in the centre of its length, in order to break the specimen. Thus, the energy leading to the break of the specimen can be determined, i.e. the product of the force at break and the strain at break. The results are given in cardinality 100, i.e. the values ​​are expressed relative to a control, the measured values ​​of which are considered as reference values ​​of 100.

[0166] Thus, lower values ​​of energy to break indicate reduced tear strength performance (ie, reduced energy to break), while higher values ​​indicate better performance.

[0167] Swelling index

[0168] The swelling index was determined by means of a Rheograph 75 rheometer equipped with a camera system (i2S, reference number 21400328).

[0169] The rheometer consists of 2 identical and parallel tanks (20 mm diameter). The tanks are heated to the test temperature. A single tank is used to measure the swelling (barrel number 1).

[0170] The mixture to be tested is placed in a tank; it is then compressed by a piston and forced out through a die located at the bottom of the tank (extrusion of the mixture). The length, diameter and surface conditions of the two dies are known. The piston moves horizontally at various speeds predefined by the user. The pressure is measured throughout the acquisition process in order to be able to calculate the rheological properties of the material.

[0171] The measurement result is the result of a single measurement. The result obtained is the swelling index (unitless) for each speed level.

[0172]

[0173] The results are expressed relative to a control sample on a base 100 basis (the control sample was given a value of 100).

[0174] Preparation of rubber composition:

[0175] The composition is manufactured in a suitable mixer using two consecutive preparation stages known to those skilled in the art: a first stage of thermomechanical processing or kneading at high temperature (up to a maximum temperature of between 110° C. and 200° C., preferably between 130° C. and 180° C.) (sometimes called the “non-preparation” stage), followed by a second stage of mechanical processing at a lower temperature, generally below 110° C., for example between 60° C. and 100° C. (sometimes called the “preparation” stage), during which a crosslinking or vulcanization system is conventionally introduced; such stages have been described, for example, in applications EP-A-0501227, EP-A-0735088, EP-A-0810258, WO 00 / 05300 or WO 00 / 05301.

[0176] The composition was cured at 140°C for 50 minutes.

[0177] test

[0178] The tests were conducted using various rubber compositions shown in Table 1.

[0179] The formula of the prepared composition is shown in Table 1 (components and contents - unless otherwise specified, the contents are expressed in phr).

[0180] Table 1: Formula of the composition

[0181] T C1 C2 INV Natural rubber 50.00 50.00 50.00 50.00 Polybutadiene 50.00 50.00 50.00 50.00 Carbon black, ASTM grade N234 33.50 3.00 3.00 3.00 Pyrolytic Carbon Black(2) 16.25 Silica (3) 10.00 33.00 51.50 33.00 Antioxidants (4) 8.90 8.90 8.90 8.90 Anti-ozone 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

[0182] (1) WTR80-0 sold by Lehigh Technologies

[0183] (2) P550 sold by Scandinavian Enviro Systems ((%) ash: 18.5; (%) sulfur: 3; (%) zinc: 4.5; STSA specific surface area: 56m 2 / g (ASTM D6556-2021); void volume at 50MPa: 44ml / 100g (ASTM D7854-21))

[0184] (3) Sold by Evonik 7000GR

[0185] (4) A combination of two antioxidants TMQ (N-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine (Santoflex 6-PPD from Flexsys) and 2,2,4-trimethyl-1,2-dihydroquinolone (TMQ from Lanxess))

[0186] (5) Zinc oxide (industrial grade), sold by Umicore

[0187] (6) Stearin sold under the name Pristerene 4931 by Uniqema

[0188] (7) N-cyclohexyl-2-benzothiazole sulfenamide sold under the name Santocure CBS by Flexsys

[0189] (8) Diphenylguanidine, Perkacit DPG from Flexsys

[0190] Table 2 lists the properties of the compositions measured in the cured state.

[0191] Table 2: Properties of the compositions

[0192]

[0193] The tests performed show that a reduction in the content of reinforcing filler in the rubber composition leads to an increase in the composition showing hysteresis (compositions T and C1). However, this increase in hysteresis is accompanied by a reduction in the tearing fracture energy and a deterioration in the processability of the composition (SI 80s-1). Specifically, the swelling of the composition reaches a level that reduces the performance of the composition in commonly used industrial equipment.

[0194] By comparing compositions C1 and C2, it can be observed that an increase in the total volume of filler reduces swelling. However, this effect is accompanied by a decrease in the quality of the rolling resistance performance (increase in G" 10% return).

[0195] Surprisingly, it is observed that, with the same total volume of filler (comparison of compositions C2 and INV), partial replacement of silica by pyrolytic carbon black allows a good compromise between performance qualities and processability to be achieved.

Claims

1. A tire having a sidewall comprising at least one rubber composition based on: - at least one elastomer; - 16% to 20% by volume of reinforcing fillers relative to the total volume of the composition; and - Cross-linking system; The reinforcing filler comprises: - 6% to 16% by volume, preferably 6% to 11% by volume, of reinforcing fillers, relative to the total volume of the composition, the reinforcing fillers being selected from reinforcing inorganic fillers, CTAB with a specific surface area greater than or equal to 90 m 2 / g of carbon black, and the specific surface area of ​​the reinforcing inorganic filler and CTAB is greater than or equal to 90m 2 / g of carbon black, wherein the reinforcing inorganic filler accounts for the main mass; - Pyrolytic carbon black in an amount sufficient to bring the volume of reinforcing filler in the composition to 16% to 20% relative to the total volume of the composition.

2. The tire according to claim 1, wherein: The or each elastomer is a diene elastomer chosen from polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

3. The tire according to claim 1 or 2, wherein: The rubber composition comprises 25 to 100 phr of natural rubber and 0 to 75 phr of at least one polybutadiene.

4. The tire according to claim 3, wherein: The rubber composition includes 50 phr of natural rubber and 50 phr of polybutadiene.

5. The tire according to any one of claims 1 to 4, wherein: CTAB specific surface area is greater than or equal to 90m 2 The carbon black of / g is selected from 100 series and 200 series reinforcing carbon black.

6. The tire according to any one of claims 1 to 5, wherein: The reinforcing inorganic filler is silicon dioxide.

7. A tyre according to any one of the preceding claims, wherein: The crosslinking system is a vulcanization system based on molecular sulfur and / or sulfur-donating agents.

8. A tyre according to any one of the preceding claims, wherein: The vulcanization system comprises between 0.5 and 10 phr of sulphur, preferably between 1 and 5 phr of sulphur.

9. A tyre according to any one of the preceding claims, wherein: The ash content of the pyrolytic carbon black is 5 to 30 wt %, preferably 8 to 25 wt %, relative to the total weight of the pyrolytic carbon black.

10. The tire according to any one of the preceding claims, wherein: The sulfur content of the pyrolytic carbon black is greater than 2% by weight, preferably 2.5% to 5% by weight, relative to the total weight of the pyrolytic carbon black.

11. The tire according to any one of the preceding claims, wherein: The composition may also contain 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.

12. A tyre according to any one of the preceding claims, wherein: The reinforcing filler is a reinforcing inorganic filler or a reinforcing inorganic filler and CTAB with a specific surface area greater than or equal to 90 m 2 / g of carbon black, wherein the reinforcing inorganic filler accounts for the main mass.

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