Tire

Abstract

The invention relates to a tyre comprising two beads, wherein at least one bead comprises a rubber composition based on the following components: at least one elastomer; -from 60 phr to 100 phr of a reinforcing filler comprising from 15 phr to 70 phr of pyrolytic carbon black and from 15 phr to 60 phr of carbon black wherein the total content of carbon black and pyrolytic carbon black is from 60 phr to 90 phr; and-a crosslinking system.

Description

Technical Field

[0001] The present invention relates to a tire, particularly a tire for passenger vehicles. Background Art

[0002] Tires for passenger vehicles generally include:

[0003] - Two beads, which are intended to come into contact with the mounting support;

[0004] - Two sidewalls, which extend radially outwards from the beads and converge in the crown, the crown including a tread and a crown reinforcement;

[0005] - At least one carcass reinforcement, which extends radially in each sidewall and axially in the crown, and extends radially on the inner side of the crown reinforcement.

[0006] Each bead contains a rubber composition that withstands high stresses. Therefore, they must have both sufficient stiffness and good rolling resistance performance, and sufficient adhesion to resist external physical attacks, for example, during the installation or removal of the tire.

[0007] In the context of the ongoing search to improve tires and reduce their environmental impact, manufacturers aim to develop new rubber compositions that meet the above criteria and others. Therefore, one of the aims of the present invention is to provide a tire whose beads have a good balance of stiffness / tear strength and do not compromise hysteresis, while also containing a significant amount of recycled materials. Summary of the Invention

[0008] The present invention relates to a tire including two beads, wherein at least one bead contains a rubber composition based on the following components:

[0009] - At least one elastomer;

[0010] - 60 phr to 100 phr of reinforcing filler, wherein 15 phr to 70 phr is pyrolytic carbon black, 15 phr to 60 phr is carbon black, and the total content of carbon black and pyrolytic carbon black is 60 phr to 90 phr; and

[0011] - A crosslinking system.

[0012] Other aspects of the present invention are as described below and in the claims.

[0013] Definitions

[0014] The expression "the composition is based on" is to be understood as meaning that the composition comprises a mixture of the various components used and / or an in-situ reaction product, some of these components being capable of and / or intended to react at least partially with one another during the course of the various stages of manufacture of the composition; thus the composition can be in a fully crosslinked or partially crosslinked state or in a non-crosslinked state.

[0015] Within the meaning of the present invention, the expression "parts by weight / 100 parts by weight of elastomer" (or phr) is to be understood as meaning parts by weight / 100 parts by weight of elastomer or rubber, the two terms being synonymous.

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

[0017] Furthermore, any numerical interval represented by the expression "between a and b" represents a numerical range extending from greater than a to less than b (i.e. excluding the end values a and b), while any numerical interval represented by the expression "from a to b" means a numerical range extending from a up to b (i.e. including the exact end values a and b). In the present text, when a numerical interval is described by the expression "from a to b", it is also preferred to state that the interval can be represented by the expression "between a and b".

[0018] The expression "radial" refers to the radius of the tyre. In this sense, if point P1 is closer to the axis of rotation of the tyre than point P2, then point P1 is said to be "radially inside" (or "inside point P2 radially") point P2. Conversely, if point P3 is further from the axis of rotation of the tyre than point P4, then point P3 is said to be "radially outside" (or "outside point P4 radially") point P4. When the direction of movement is along the shorter (or longer) radius, the movement is said to be "radially inwards (or outwards)". This meaning of the terms also applies when referring to radial distances.

[0019] The term "radial cross-section" or "radial section" is understood here to mean a cross-section or section along a plane containing the axis of rotation of the tyre.

[0020] The "axial" direction is the direction parallel to the axis of rotation of the tyre. If point P5 is closer to the median plane of the tyre than point P6, then point P5 is said to be "axially inside" (or "inside point P6 axially") point P6. Conversely, if point P7 is further from the median plane of the tyre than point P8, then point P7 is said to be "axially outside" (or "outside point P8 axially") point P8. The "median plane" of the tyre is a plane perpendicular to the axis of rotation of the tyre and equidistant from the annular reinforcing structure of each bead.

[0021] The "circumferential" direction is the direction perpendicular to both the radius and the axial direction of the tyre in each meridian cross-section.

[0022] The carbon-containing compounds mentioned in this specification can be of fossil origin or biobased compounds. In the latter case, they can be obtained in part or in whole from biomass or can be obtained from renewable raw materials derived from biomass. This specifically relates to polymers, plasticizers, fillers, etc.

[0023] The inventors have developed a rubber composition that meets the above requirements.

[0024] Accordingly, the present invention relates to a tire comprising two beads, wherein at least one bead comprises a rubber composition based on the following components:

[0025] - at least one elastomer;

[0026] - 60 phr to 100 phr of reinforcing filler, wherein 15 phr to 70 phr is pyrolytic carbon black and 15 phr to 60 phr is carbon black, and the total content of carbon black and pyrolytic carbon black is 60 phr to 90 phr; and

[0027] - a crosslinking system.

[0028] The rubber composition may further comprise crumb rubber and / or common additives and processing aids.

[0029] The various components of the rubber composition can be as described below.

[0030] Elastomer

[0031] The composition used in the context of the present invention is based on at least one elastomer (or equivalently, rubber).

[0032] The elastomer or each elastomer can be selected from diene elastomers and mixtures thereof.

[0033] The term "diene elastomer", whether natural or synthetic, should be understood in a known manner to mean an elastomer that consists at least in part (i.e., homopolymer or copolymer) of diene monomer units (monomers with two conjugated or non-conjugated carbon-carbon double bonds).

[0034] These diene elastomers can be divided into two categories: "substantially unsaturated" or "substantially saturated". The term "substantially unsaturated" is generally understood to mean a diene elastomer that is at least partially derived from conjugated diene monomers having a diene source (conjugated diene) subunit or unit content greater than 15% (mol%); thus, diene elastomers such as butyl rubber or copolymers of dienes and α-olefins of the EPDM type do not fall within the foregoing definition and can be specifically referred to as "substantially saturated" diene elastomers (low or very low diene source subunit content, always less than 15%).

[0035] The term "usable diene elastomer" is specifically understood to mean:

[0036] (a) - Any homopolymer obtained by the polymerization of conjugated or non-conjugated diene monomers having 4 to 18 carbon atoms;

[0037] (b) - Any copolymer obtained by the copolymerization of conjugated or non-conjugated dienes having 4 to 18 carbon atoms with at least one other monomer.

[0038] The other monomer can be ethylene, an olefin, or a conjugated or non-conjugated diene.

[0039] Suitable conjugated dienes include conjugated dienes having 4 to 12 carbon atoms, especially 1,3-dienes, especially for example 1,3-butadiene and isoprene.

[0040] Suitable olefins include vinyl aromatic compounds having 8 to 20 carbon atoms and aliphatic α-monoolefins having 3 to 12 carbon atoms.

[0041] Suitable vinyl aromatic compounds include, for example, styrene, o-methylstyrene, m-methylstyrene or p-methylstyrene, the commercial mixture "vinyltoluene" or p-(tert-butyl)styrene.

[0042] Suitable aliphatic α-monoolefins specifically include acyclic aliphatic α-monoolefins having 3 to 18 carbon atoms.

[0043] More specifically, the diene elastomers that can be used in the composition can be:

[0044] (a') - Any homopolymer obtained by the polymerization of conjugated diene monomers having 4 to 12 carbon atoms;

[0045] (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;

[0046] (c') - Any copolymer obtained by copolymerizing one or more conjugated or non-conjugated dienes with ethylene, an α-monoolefin or a mixture thereof, for example an elastomer obtained from ethylene, propylene and non-conjugated diene monomers of the above type.

[0047] Preferably, the diene elastomer is selected from polybutadiene (BR), natural rubber (NR), synthetic polyisoprene (IR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers. The butadiene copolymers are particularly selected from butadiene / styrene copolymers (SBR).

[0048] The diene elastomer can be modified, i.e., coupled and / or star-branched, or functionalized, or coupled and / or star-branched and simultaneously functionalized.

[0049] Thus, the diene elastomers can be coupled and / or star-branched, for example, by silicon or tin atoms that link the elastomer chains together.

[0050] The diene elastomers can be functionalized simultaneously or alternately and contain at least one functional group. The term "functional group" should be understood to mean a group containing at least one heteroatom selected from Si, N, S, O, or P. Particularly suitable as functional groups are those containing at least one functional group, such as: silanols, alkoxysilanes, cyclic or acyclic primary, secondary, or tertiary amines, thiols, or epoxides.

[0051] The rubber composition used in the context of the present invention can contain only one diene elastomer or a mixture of several diene elastomers.

[0052] In some embodiments, the rubber composition used in the context of the present invention contains one or more elastomers; thus, it can contain 25 phr to 100 phr of natural rubber and 0 phr to 75 phr of at least one polybutadiene, preferably 35 phr to 75 phr of natural rubber and 25 phr to 65 phr of at least one polybutadiene.

[0053] In some embodiments, the rubber composition used in the context of the present invention contains a mixture of natural rubber (NR) and at least one polybutadiene (BR) as elastomers. Preferably, the mixture consists of 50 phr of natural rubber (NR) and 50 phr of polybutadiene (BR).

[0054] Reinforcing filler

[0055] The composition used in the context of the present invention contains 60 phr to 100 phr of reinforcing filler.

[0056] The term "reinforcing filler" denotes any type of filler known to be capable of reinforcing rubber compositions that can be used particularly in the manufacture of tires, such as organic fillers (e.g., carbon black or pyrolytic carbon black) or inorganic fillers (e.g., silica or alumina). It should be understood that, within the meaning of the present invention, crumb rubber is not a reinforcing filler, and any reinforcing filler it may contain is not taken into account when calculating the total content of reinforcing filler in the composition.

[0057] Specifically, the composition used in the context of the present invention comprises 15 phr to 70 phr of pyrolytic carbon black and 15 phr to 60 phr of carbon black, wherein the total content of carbon black and pyrolytic carbon black ranges from 60 phr to 90 phr or 60 phr to 80 phr or 60 phr to 78 phr. Thus, the composition may further comprise an inorganic reinforcing filler (such as silica or alumina) or an organic reinforcing filler other than carbon black and pyrolytic carbon black, so as to achieve a total content range of reinforcing filler from 60 phr to 100 phr. If the filler is below 60 phr, the required stiffness cannot be achieved, while if the filler is above 100 phr, industrial implementation is too difficult and the hysteresis level is too high.

[0058] In some embodiments, the composition comprises 60 phr to 90 phr, preferably 60 phr to 80 phr or 60 phr to 78 phr of reinforcing filler, which consists of a mixture of carbon black and pyrolytic carbon black. Thus, it should be understood that the composition comprises carbon black and pyrolytic carbon black as the sole reinforcing fillers (so the composition does not contain any inorganic reinforcing filler or other organic reinforcing filler). Thus, preferably, the mixture comprises 30 phr to 60 phr of pyrolytic carbon black and 20 phr to 40 phr of carbon black.

[0059] The reinforcing filler can be as described below.

[0060] Pyrolytic carbon black

[0061] The composition used in the context of the present invention comprises 15 phr to 70 phr of pyrolytic carbon black, preferably 30 phr to 60 phr of pyrolytic carbon black.

[0062] In the context of the present invention, the term "pyrolytic carbon black" refers to carbon black produced by the pyrolysis process of a material (hereinafter referred to as the material to be pyrolyzed) that at least contains a carbon-based polymer and carbon black, for example, in the case of recycling such a material. The physical state of the provided material to be pyrolyzed is not important, whether it is in powder, granule, strip or any other form, in a crosslinked or non-crosslinked state.

[0063] Preferably, the material to be pyrolyzed can be recovered from articles or from products (such as by-products or waste) generated during their manufacturing / production process; these articles can be selected from pneumatic tires, non-pneumatic tires, industrial conveyor belts, drive belts, rubber seals, rubber hoses, shoe soles and windshield wipers. More preferably, the pyrolytic carbon black used in the context of the present invention is carbon black obtained from a pyrolysis process, wherein the material to be pyrolyzed is derived from articles selected from pneumatic tires and non-pneumatic tires.

[0064] In the context of the present invention, "pyrolysis" refers to any type of thermal decomposition under anaerobic conditions, where the raw material is the material to be pyrolyzed as defined above. Thus, pyrolytic carbon black differs from "industrial" and / or "ASTM grade" carbon black in that the carbon-based raw material used for pyrolysis is a material that contains 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.

[0065] The pyrolytic carbon black that can be used in the context of the present invention differs from known carbon blacks (such as industrial carbon black, especially "furnace" carbon black), in particular by having a higher ash content.

[0066] Preferably, relative to the total weight of the pyrolytic carbon black, the ash content of the pyrolytic carbon black that can be used in the context of the present invention ranges from 5 wt% to 30 wt%, more preferably from 8 wt% to 25 wt%, and even more preferably from 10 wt% to 22 wt%.

[0067] - Preferably, relative to the total weight of the pyrolytic carbon black, the sulfur content of the pyrolytic carbon black that can be used in the context of the present invention is greater than 2 wt%, preferably from 2.5 wt% to 5 wt%.

[0068] - Preferably, relative to the total weight of the pyrolytic carbon black, the zinc content of the pyrolytic carbon black that can be used in the context of the present invention is greater than or equal to 2 wt%, preferably from 2.5 wt% to 8 wt%.

[0069] - Preferably, the pyrolytic carbon black that can be used in the context of the present invention has a STSA specific surface area measured according to standard ASTM D 6556-2021 in the range of 20 m 2 / g to 200 m 2 / g, more preferably in the range of 30 m 2 / g to 90 m 2 / g.

[0070] - Preferably, the pyrolytic carbon black that can be used in the context of the present invention has a void volume in the range of 30 to 60 mL / 100 g, more preferably 35 to 55 mL / 100 g, measured according to standard ASTM D7854-21 and at a pressure of 50 MPa.

[0071] The ash content is determined by calcining in a platinum dish in a muffle furnace at 825 °C according to the following protocol. Before each series of measurements, a dish is pre-determined and its tare weight is weighed to within 0.1 mg, and the mass is expressed as P0. Place 5 g of the pyrolytic carbon black sample (accurately weighed to within 0.1 mg) into the dish; express this mass as P1. Pre-calcine the dish and its contents using a Bunsen burner until smoke appears and the product ignites. Once the product combustion is complete, place the dish and its contents into a muffle furnace heated to 825 °C for 1 hour. After 1 hour, remove the dish from the furnace and immediately place it in a desiccator at ambient temperature. When the dish and the ash have returned to ambient temperature, weigh the dish again to obtain the mass P2. Finally, the ash content (% ash) can be obtained using the following formula:

[0072]

[0073] After the sample is calcined, the ash is then absorbed into an acidic medium and determined by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometry) to obtain the zinc content in the pyrolytic carbon black. The ash is obtained by performing the above protocol. Take approximately exactly 100 mg of the ash (test sample) and introduce it into a PFA (Perfluoroalkoxy) tube on 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 it at 130 °C for 2 hours. After cooling, transfer the contents to a 100 mL PTFE (Polytetrafluoroethylene) volumetric flask that already contains 2 g of boric acid (for neutralizing hydrofluoric acid) using ultrapure water. Add ultrapure water up to the calibration mark. Dilute the resulting solution 100-fold by placing 1 mL of the solution into a 100 mL PFTE flask that already contains 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, 0.5 mL of 40% hydrofluoric acid, and 2 g of boric acid. Then filter the diluted solution through a 0.45 µm GHP syringe filter and then analyze it by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). Before analyzing the diluted solution, use ICP-AES to analyze at least 5 standard samples with zinc concentrations of 0, 0.5, 1, 2, and 5 mg / L. These standard samples are prepared by diluting a commercial solution with a certified zinc concentration of 1 g / L in a 100 mL volumetric flask.

[0074] These volumetric flasks already contain 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, 0.5 mL of 40% hydrofluoric acid, and 2 g of boric acid. The standard solutions are analyzed by ICP - AES (at a wavelength of λZn = 202.613 nm). For each standard concentration (c), the intensity of the zinc signal IZn is plotted on a graph IZn = f(c), which corresponds to a calibration straight line (type y = ax + b). Then, the sample solution of unknown concentration (diluted solution) is measured under the same conditions as the standard samples. Using the previously obtained calibration straight line, the measured intensity is related to the concentration. Since the test samples and volumes have been recorded beforehand, the ash concentration [c] expressed in mass% is directly obtained by software. The concentration [c] of zinc in the pyrolytic carbon black expressed in mass% is obtained by the following formula 炭黑 :

[0075] [c] 炭黑 = [c] 灰分 * 100 * % ash

[0076] The sulfur content in the pyrolytic carbon black is determined using a LECO furnace. The LECO sulfur analyzer is designed to specifically measure the sulfur content in organic and / or inorganic materials by combustion and non - dispersive infrared detection. Before measuring the sulfur content in the sample, the boats are cleaned and the furnace is calibrated. The boats of the LECO furnace have been previously cleaned: this involves analyzing an empty boat under the same conditions as the sample. The calibration curve is plotted using a commercial standard sample called "BBOT", which has a purity greater than 99.99% and guaranteed contents of carbon (C), hydrogen (H), nitrogen (N), oxygen (O), and sulfur (S). The contents are as follows: C%: 72.52; H%: 6.09; N%: 6.51; O%: 7.43 and S%: 7.44. Approximately exactly 10 ± 3, 20 ± 3, and 40 ± 3 mg of BBOT are weighed and placed in the boat. The standard sample / boat assembly is placed in the combustion furnace and adjusted to 1350 °C under pure oxygen. The combination of the furnace temperature and the analysis flow rate causes the combustion of the sample and releases sulfur and / or carbon in the form of SO 2 (g). After 20 seconds, oxygen starts to flow through the lance to accelerate the combustion of refractory materials. Sulfur and / or carbon are entrained by the oxygen flow in the form of SO 2 (g) through the infrared detection chamber. The instrument software plots a straight line relating the introduced standard mass to the response (area) observed on the detector. In this way, a calibration straight line is obtained. After carefully cleaning the sampling equipment, approximately exactly 80 ± 5 mg of pyrolytic carbon black is weighed and placed in the boat of the LECO furnace. The observed area of the SO 2 peak is related to the concentration using the calibration straight line. Then the instrument software calculates the mass% of sulfur in the sample using the mass of the sample placed in the boat.

[0077] For example, pyrolytic carbon black is sold by BlackBear with reference to "BBCT30" or by Scandinavian Enviro Systems with reference to "P550".

[0078] Carbon black

[0079] The composition used in the context of the present invention comprises from 15 phr to 60 phr of carbon black, preferably from 20 phr to 40 phr of carbon black.

[0080] Suitable carbon blacks include all carbon blacks, in particular those commonly used in tires or their treads, in particular industrial carbon blacks, more specifically "furnace" carbon blacks.

[0081] Among the carbon blacks, reinforcing carbon blacks of the 100, 200 and 300 series, or carbon blacks of the 500, 600 or 700 series (ASTM D-1765-2017 grades), such as N115, N134, N234, N326, N330, N339, N347, N375, N550, N683 and N772 carbon blacks, will be mentioned more particularly. Carbon blacks that can be used are those that are commercially available in a separate state, or carbon blacks that can be used in any other form, for example, carbon blacks supported by some rubber additives used. The carbon black can, for example, already have been introduced in the form of a masterbatch into a diene elastomer, in particular an isoprene elastomer (for example, see patent applications WO 97 / 36724-A2 and WO 99 / 16600-A1).

[0082] Reinforcing inorganic filler

[0083] The composition used in the context of the present invention may include a reinforcing inorganic filler.

[0084] The term "reinforcing inorganic filler" should be understood herein to mean any inorganic or mineral filler, regardless of its color and its origin (natural or synthetic), which is also called a "white" filler, a "transparent" filler or even a "non-black" filler compared to carbon black, and which is capable of reinforcing alone the rubber composition intended for the manufacture of tires without means other than an intermediate coupling agent. In a known manner, some reinforcing inorganic fillers may be characterized in particular by the presence of hydroxyl (-OH) groups on their surface.

[0085] Mineral fillers of the siliceous type (preferably silica (SiO 2 )) or of the aluminous type (in particular alumina (Al 2 O 3 )) are particularly suitable as reinforcing inorganic fillers. The silica used can be any reinforcing silica known to those skilled in the art, in particular silica having a BET specific surface area and a CTAB specific surface area both less than 450 m 2 / g, preferably in the range of 30 to 400 m 2 / g, especially 60 to 300 m 2 / g of any precipitated silica or fumed silica within the range.

[0086] Any type of precipitated silica can be used, especially highly dispersible precipitated silica (HDS, i.e., "highly dispersible silica"). These precipitated silicas (whether or not highly dispersible) are well-known to those skilled in the art. For example, the silicas described in applications WO 03 / 016215 - A1 and WO 03 / 016387 - A1 can be mentioned. Among the commercially available HDS silicas, those from Evonik's 5000GR and 7000GR silica, or those from Solvay's 1085GR, 1115MP, 1165MP, Premium 200MP and HRS 1200MP silica can be especially used. As non - HDS silica, the following commercially available silicas can be used: those from Evonik's VN2GR and VN3GR silica, those from Solvay's 175GR silica, or those from PPG's Hi - Sil EZ120G(-D), Hi - Sil EZ160G(-D), Hi - Sil EZ200G(-D), Hi - Sil 243LD, Hi - Sil 210 and Hi - Sil HDP 320G.

[0087] The BET specific surface area of the silica is determined in a known manner by gas adsorption using the Brunauer - Emmett - Teller method described in "The Journal of the American Chemical Society" (Volume 60, page 309, February 1938), more particularly in accordance with the French standard NF ISO 9277 of December 1996 [multi - point (5 - point) volume method - gas: nitrogen - degassing: 1 hour at 160 °C – relative pressure p / po range: 0.05 to 0.17]. The CTAB specific surface area of the silica is determined in accordance with the French standard NF T 45 - 007 (method B) of November 1987.

[0088] As other examples of inorganic fillers that can be used in the composition, mineral fillers of the aluminous type can also be mentioned, especially alumina (Al2 O 3 ) alumina, aluminum hydroxide, aluminum silicate, titanium oxide, silicon carbide or silicon nitride, all types of reinforcement as described, for example, in patent applications WO 99 / 28376 - A2, WO 00 / 73372 - A1, WO 02 / 053634 - A1, WO2004 / 003067 - A1, WO 2004 / 056915 - A2, US 6 610 261 - B1 and US 6 747 087 - B2. Alumina Baikalox A125 or CR125 may be specifically mentioned APA - 100 RDX (Condéa), Aluminoxid C (Evonik) or AKP - G015 (Sumitomo Chemicals).

[0089] The physical state of the provided reinforcing inorganic filler is not important, whether it is in the form of powder, microbeads, granules or beads or any other suitable densified form. Of course, the term "reinforcing inorganic filler" is also understood to mean a mixture of different reinforcing inorganic fillers, in particular a mixture of silica as described above.

[0090] Those skilled in the art will understand that a reinforcing filler of another nature may be used to replace the above - mentioned reinforcing inorganic filler, provided that the other reinforcing filler is covered by an inorganic layer (such as silica) or includes functional sites (in particular hydroxyl sites) on its surface for which a coupling agent is required to establish a bond between the reinforcing filler and the diene elastomer. For example, carbon black partially or fully covered with silica, or carbon black modified with silica, such as but not limited to those of the CRX2000 series or CRX4000 series obtained from Cabot Corporation may be mentioned type of filler.

[0091] Those skilled in the art will know how to adjust the total content of the reinforcing filler according to the use considered, in particular according to the type of tire considered (such as a tire for a motorcycle, a passenger vehicle or a multi - purpose vehicle such as a van or a heavy vehicle).

[0092] In order to couple an enhanced inorganic filler to a diene elastomer, at least a bifunctional coupling agent (or binder) designed to provide a satisfactory chemical and / or physical connection between the inorganic filler (on the surface of its particles) and the diene elastomer can be used in a known manner. In particular, at least a bifunctional organosilane or polyorganosiloxane is used. The term "bifunctional" is understood to mean that the compound has a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the diene elastomer. For example, such a bifunctional compound may contain a first functional group containing a silicon atom and a second functional group containing a sulfur atom, the first functional group being capable of interacting with the hydroxyl groups of the inorganic filler and the second functional group being capable of interacting with the diene elastomer.

[0093] Preferably, the organosilane is selected from (symmetric or asymmetric) organosilane polysulfides, such as bis(3-triethoxysilylpropyl)tetrasulfide abbreviated as TESPT sold by Evonik under the name Si69 or bis(3-triethoxysilylpropyl)disulfide abbreviated as TESPD sold by Evonik under the name Si75, polyorganosiloxanes, mercapto silanes, capped mercapto silanes, such as S-[3-(triethoxysilyl)propyl] thiooctanoate sold by Momentive under the name NXT silane. More preferably, the organosilane is an organosilane polysulfide.

[0094] Examples of coupling agents can be found by those skilled in the art in the following documents: WO 02 / 083782, WO 02 / 30939, WO 02 / 31041, WO 2007 / 061550, WO 2006 / 125532, WO 2006 / 125533, WO 2006 / 125534, US 6849754, WO 99 / 09036, WO 2006 / 023815, WO 2007 / 098080, WO 2010 / 072685 and WO 2008 / 055986.

[0095] The content of the coupling agent preferably accounts for 0.5 wt% to 15 wt% of the enhanced inorganic filler, preferably 4 wt% to 12 wt% of the enhanced inorganic filler, more preferably 6 wt% to 10 wt%. Generally, the content of the coupling agent is less than 20 phr, preferably in the range of 6 phr to 17 phr, preferably 8 phr to 15 phr. This content can be easily adjusted by those skilled in the art according to the content of the inorganic filler used in the composition.

[0096] In addition to the coupling agent, the composition may further comprise a coupling activator, a reagent for coating the inorganic filler or more common processing aids, which are capable of improving the processability of the composition in the unprocessed state in a known manner by improving the dispersion of the filler in the rubber matrix and reducing the viscosity of the composition. These processing aids are, for example, hydrolyzable silanes such as alkylalkoxysilanes (especially alkyltriethoxysilanes), polyols, polyethers (such as polyethylene glycol), primary amines, secondary amines or tertiary amines (such as trialkanolamines), hydroxylated or hydrolyzable POS such as α,ω-dihydroxypolyorganosiloxanes (especially α,ω-dihydroxypolydimethylsiloxanes), or fatty acids such as stearic acid.

[0097] Other organic filler

[0098] As an example of an organic filler other than carbon black and pyrolytic carbon black, mention may be made, for example, of the functionalized polyvinyl organic fillers described in applications WO 2006 / 069792-A1, WO 2006 / 069793-A1, WO 2008 / 003434-A1 and WO 2008 / 003435-A1.

[0099] Rubber crumbs

[0100] The composition used in the context of the present invention may comprise crumb rubber (abbreviated as "crumb" in the remainder of this text). Thus, the composition generally comprises from 0 to 20 phr of crumb rubber.

[0101] In some embodiments, the composition does not comprise crumb rubber.

[0102] In some embodiments, the composition comprises crumb rubber in an amount greater than 0 phr and less than or equal to 20 phr, such as from 1 phr to 20 phr or from 10 phr to 20 phr.

[0103] The crumb is in particulate form, optionally in the form of rubber sheets. Generally, crumb rubber is produced by grinding or micronizing a cured rubber composition that has been used in a first application (such as in a tire); they are a product of material recycling. Thus, the crumb preferably consists of a composition based on at least one elastomer and a filler. The crumb is preferably in the form of fine particles.

[0104] The term "fine particles" is intended to mean particles having such dimensions that their diameter in the case of spherical particles or their maximum dimension in the case of non-equiaxial particles is in the order of tens or hundreds of micrometers.

[0105] The debris preferably consists of a composition based on an elastomer and a filler. They may also contain all the components commonly used in rubber compositions, such as plasticizers, antioxidants, vulcanization additives, etc.

[0106] Thus, the debris includes an elastomer, preferably a diene elastomer. Relative to the weight of the debris, this elastomer preferably accounts for at least 30% by mass, more preferably at least 35% by mass, and even more preferably at least 45% by mass, said percentages being determined according to standard ASTM E1131. It is preferably selected from polybutadiene, polyisoprene (including natural rubber), butadiene copolymers, and isoprene copolymers. More preferably, the molar content of the diene source (conjugated diene) subunits present in the diene elastomer is greater than 50%, preferably between 50% and 70%.

[0107] According to a preferred embodiment of the present invention, the debris contains a filler in an amount between 5% and 80% by mass, more preferably between 10% and 75% by mass, and very preferably between 15% and 70% by mass.

[0108] In the present context, the term "filler" is understood to mean any type of filler, whether it is reinforcing (usually preferably having a weight-average size of less than 500 nanometers, especially between 20 and 200 nanometers for nanoparticles) or whether it is non-reinforcing or inert (usually preferably having a weight-average size greater than 1 micrometer, such as between 2 and 200 micrometers for microparticles). The weight-average size of the nanoparticles is measured in a manner well known to those skilled in the art (for example, according to paragraph 1.1 of application WO 2009 / 083160). The weight-average size of the microparticles can be determined by mechanical sieving.

[0109] As examples of what those skilled in the art call reinforcing fillers, mention will be made in particular of carbon black or reinforcing inorganic fillers (such as silica or alumina in the presence of a coupling agent), or mixtures thereof.

[0110] According to a preferred embodiment of the present invention, the debris contains a reinforcing filler, especially carbon black or a mixture of carbon blacks as the filler.

[0111] Relative to the weight of the reinforcing filler in the debris, the carbon black or the mixture of carbon blacks preferably accounts for more than 50%, more preferably more than 80%, and even more preferably more than 90% (by mass). According to a more preferred embodiment, the reinforcing filler consists of carbon black or a mixture of carbon blacks.

[0112] Very preferably, the carbon black content present in the debris ranges from 20% to 40% (by mass), more preferably from 25% to 35% (by mass).

[0113] All carbon blacks, in particular HAF, ISAF, SAF, FF, FEF, GPF, and SRF types of carbon blacks ("tire-grade" carbon blacks) commonly used in tire rubber compositions, are suitable as the carbon black.

[0114] The fines can include all other common additives involved in rubber compositions, especially those for tire rubber compositions. Among these common additives, mention can be made of liquid or solid plasticizers, non-reinforcing fillers (such as chalk, kaolin), protective agents, and vulcanizing agents. These additives can also be present in the fines in the form of residues or derivatives, as they are capable of reacting during the steps of manufacturing the composition or crosslinking the composition derived from the fines.

[0115] Regarding the composition of the fines, for the purposes of the present invention, preferably, the fines have an acetone extract between 3% and 30% by weight, more preferably in the range of 5% to 25% by weight.

[0116] Also preferably, the fines have a chloroform extract between 5% and 85% by weight, more preferably in the range of 5% to 50% by weight.

[0117] The fines can be a simple rubber material that has been ground / micronized without any other treatment. It is also known that these fines can be subjected to treatment to modify them. Such treatment can include chemical functionalization or devulcanization modification. It can also be a thermomechanical, thermochemical, biological, or other similar treatment.

[0118] The grinding can be carried out by various techniques, especially cryogenic impact micronization techniques that enable small-sized particles to be obtained on the rubber material. Commercial equipment can be used, such as the CUM150 grinder from Netzsch or the CW250 grinder from Alpine.

[0119] According to a first embodiment of the present invention, it is preferred to use fines whose morphology has changed after thermal and / or mechanical and / or biological and / or chemical treatment.

[0120] According to this first embodiment, preferably, the fines have an acetone extract between 5% and 20% by weight, more preferably in the range of 10% to 18% by weight. Similarly, preferably, the fines have a chloroform extract between 15% and 85% by weight, more preferably in the range of 15% to 50% by weight. Preferably, the chloroform extract of the fines rubber has a weight-average molecular weight (Mw) greater than 10,000 g / mol, preferably greater than 20,000 g / mol, and more preferably greater than 30,000 g / mol.

[0121] According to the first embodiment, preferably, the ratio of the chloroform extract to the acetone extract (expressed as a weight percentage) is greater than or equal to 1.5, preferably greater than 2.

[0122] Also preferably, according to this first embodiment, the crumb has a Mooney viscosity (usually expressed in Mooney units MU) between 40 and 90, preferably between 45 and 75 and more preferably between 50 and 70.

[0123] According to the second embodiment of the present invention, crumbs that have not been modified by any thermal and / or mechanical and / or biological and / or chemical treatment can be used.

[0124] According to this second embodiment, preferably, the crumb has an acetone extract between 3% and 15% by weight, more preferably in the range of 3% to 10% by weight. Also, preferably, the crumb has a chloroform extract between 3% and 20% by weight, more preferably in the range of 5% to 15% by weight. Preferably, the chloroform extract of the crumb rubber has a weight average molecular weight (Mw) of less than 10,000 g / mol, preferably less than 8,000 g / mol.

[0125] According to the second embodiment, preferably, the ratio of the chloroform extract to the acetone extract (expressed as a weight percentage) is less than 1.5.

[0126] Also preferably, according to this second embodiment, the crumb has an average particle size (D50) between 10 and 400 microns, preferably between 50 and 350 microns, more preferably between 70 and 300 microns.

[0127] The crumb rubber for the needs of the present invention is commercially available, for example, sold under the trade name PolyDyne by Lehigh Technologies.

[0128] Crosslinking system

[0129] The composition used in the context of the present invention comprises a crosslinking system.

[0130] The crosslinking system can be any type of system known to those skilled in the art in the field of tire rubber compositions. It can be particularly based on sulfur and / or peroxide and / or bismaleimide.

[0131] Preferably, the crosslinking system is based on sulfur; it is then called a vulcanization system. Sulfur can be provided in any form, especially in the form of molecular sulfur or sulfur donors. It is also preferably to have at least one vulcanization accelerator, and optionally, various known vulcanization activators such as zinc oxide, stearic acid or equivalent compounds (such as stearates), salts of transition metals, guanidine derivatives (especially diphenylguanidine), or known vulcanization retarders can also be preferably used.

[0132] The preferred content of sulfur used is between 0.5 phr and 10 phr, especially between 1 phr and 5 phr. The preferred content of vulcanization accelerator used is between 0.5 phr and 10 phr, more preferably between 0.5 phr and 5.0 phr.

[0133] As the accelerator, any compound capable of acting as an accelerator for vulcanizing diene elastomers in the presence of sulfur can be used, especially thiazole-type accelerators and their derivatives, or accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea, and xanthate types. As examples of such accelerators, the following compounds can be specifically mentioned: 2-mercaptobenzothiazole disulfide (abbreviated as MBTS), N-cyclohexyl-2-benzothiazole sulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazole sulfenamide (DCBS), N-(tert-butyl)-2-benzothiazole sulfenamide (TBBS), N-(tert-butyl)-2-benzothiazole sulfimide (TBSI), tetrabenzylthiuram disulfide (TBZTD), zinc dibenzyldithiocarbamate (ZBEC), and mixtures of these compounds.

[0134] Common additives and processing aids

[0135] The compositions used in the context of the present invention may also contain all or some of the common additives and processing aids known to those skilled in the art, which are commonly used in tire rubber compositions, such as plasticizers (e.g., plasticizing oils and / or plasticizing resins with or without tackifying properties), non-reinforcing fillers, pigments, protective agents (e.g., antiozonant waxes), chemical antiozonants, antioxidants, antifatigue agents, reinforcing resins (e.g., as described in application WO 02 / 10269).

[0136] In some embodiments, the compositions used in the context of the present invention contain a plasticizer. The content of the plasticizer is greater than 0 and less than or equal to 10 phr, for example, 1 to 5 phr.

[0137] The plasticizer is preferably selected from hydrocarbon resins, plasticizing oils, and mixtures thereof.

[0138] Plasticizing oils selected from the following are particularly suitable: naphthenic oils (high viscosity or low viscosity, especially 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 ester plasticizers, sulfonate ester plasticizers, and mixtures of these compounds.

[0139] Hydrocarbon-based resins, also known as hydrocarbon plasticizing resins, are polymers well known to those skilled in the art, based essentially on carbon and hydrogen, but which may include other types of atoms, such as oxygen, and may be used in particular as plasticizers or tackifiers in polymer matrices. They are at least partially miscible (i.e., compatible) in terms of their properties with the polymer compositions in which they are intended to be used at the contents employed, thus acting as true diluents. They have been 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 deals with their applications, particularly in the field of tire rubber engineering (5.5. “Rubber Tires and Mechanical Goods”). In a known manner, these hydrocarbon resins can also be called thermoplastic resins in the sense that they soften when heated and can thus be molded.

[0140] The softening point of hydrocarbon resins is measured according to standard ISO 4625 (“ring and ball” method). Tg is measured according to standard ASTM D3418 (1999). The macrostructure (Mw, Mn and PDI) of hydrocarbon resins is determined by size exclusion chromatography (SEC): solvent tetrahydrofuran; temperature 35 °C; concentration 1 g / l; flow rate 1 ml / min; before injection, the solution is filtered through a filter with a porosity of 0.45 microns; molar correction is carried out using polystyrene standards; a set of 3 Waters columns in series (Styragel HR4E, HR1 and HR0.5); detection is carried out by a differential refractometer (Waters 2410) and its associated operating software (Waters Empower).

[0141] Hydrocarbon resins can be of aliphatic, aromatic or aliphatic / aromatic type, i.e., based on aliphatic and / or aromatic monomers. They may be natural or synthetic and may or may not be based on petroleum (in the case of being based on petroleum, they are also called petroleum resins).

[0142] Examples of suitable aromatic monomers include styrene, α-methylstyrene, indene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, p-tert-butylstyrene, methoxystyrene, chlorostyrene, vinylmesitylene, divinylbenzene, vinylnaphthalene and any vinyl aromatic monomer derived from a C9 fraction (or more generally 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 generally from a C8 to C10 fraction). Preferably, the vinyl aromatic monomer is the minor monomer in the copolymer under consideration, expressed as a mole fraction.

[0143] 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.

[0144] The term "terpene" as used herein collectively refers to α-pinene, β-pinene, and limonene monomers in a known manner; limonene monomers exist in three possible isomeric forms in a known manner: L-limonene (left-handed enantiomer), D-limonene (right-handed enantiomer), or dipentene, i.e., the racemic mixture of the right-handed and left-handed enantiomers. Among the above hydrocarbon plasticizing resins, particular mention is made of α-pinene, β-pinene, dipentene, or poly-limonene homopolymer or copolymer resins.

[0145] High Tg hydrocarbon resins are known to be thermoplastic hydrocarbon resins with a Tg greater than 20 °C.

[0146] Preferably, the plasticizing resin is a high Tg hydrocarbon plasticizing resin having at least any one of the following characteristics:

[0147] - Tg greater than 30 °C;

[0148] - Number average molecular weight (Mn) between 300 and 2000 g / mol, more preferably between 400 and 1500 g / mol;

[0149] - Polydispersity index (PDI) less than 3, more preferably less than 2 (reminder: PDI = Mw / Mn, where Mw is the weight average molecular weight).

[0150] More preferably, this high Tg hydrocarbon plasticizing resin has all of the above preferred characteristics.

[0151] The above preferred high Tg hydrocarbon resins are well-known to those skilled in the art and are commercially available, for example, sold in the following ways:

[0152] - Poly-limonene resin: sold by DRT under the name Dercolyte L120 (Mn = 625 g / mol; Mw = 1010 g / mol; PDI = 1.6; Tg = 72 °C), or sold by Arizona under the name Sylvagum TR7125C (Mn = 630 g / mol; Mw = 950 g / mol; PDI = 1.5; Tg = 70 °C);

[0153] - C5 fraction / vinyl aromatic copolymer resins, especially C5 fraction / styrene or C5 fraction / C9 fraction: sold by Neville Chemical Company under the names Super Nevtac 78, Super Nevtac 85 or Super Nevtac 99, sold by Goodyear Chemicals under the name Wingtack Extra, sold by Kolon under the names Hikorez T1095 and Hikorez T110, sold by Exxon under the names Escorez 2101 and Escorez 1273;

[0154] - Limonene / styrene copolymer resins: sold by DRT under the name Dercolyte TS105, sold by Arizona Chemical Company under the names ZT115LT and ZT5100.

[0155] As an example of other preferred resins, mention may also be made of phenol-modified α-methylstyrene resins. To characterize these phenol-modified resins, it should be remembered that a value known as the "hydroxyl value" (measured according to standard ISO 4326 and expressed as mg KOH / g) is used in a known manner. α-Methylstyrene resins, especially phenol-modified α-methylstyrene resins, 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; 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).

[0156] Mention may also be made of resins of the alkylphenol family, such as octylphenyl formaldehyde (OPF), which can be obtained, for example, from SI Group under the name SP1068, and oleoresins, such as those provided by Costa Irmaos.

[0157] Preparation of the composition

[0158] The rubber compositions used in the context of the present invention are manufactured in two successive preparation stages known to those skilled in the art in a suitable mixer:

[0159] - The first stage of thermomechanical processing or kneading (referred to as the "non-preparation" 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, fillers and various other optional additives, are introduced into a suitable mixer such as a standard closed mixer (e.g., of the Banbury type). The fillers can be introduced into the elastomer either in one go or in several portions during the thermomechanical kneading. If the fillers have been introduced into the elastomer in the form of a masterbatch (e.g., as described in applications WO 97 / 36724 or WO 99 / 16600), the masterbatch is directly kneaded and, where appropriate, other elastomers or fillers not in the form of a masterbatch present in the composition, as well as various other optional additives except the crosslinking system, are introduced.

[0160] The non-preparation stage is carried out at a high temperature up to a maximum temperature between 130 °C and 170 °C for a period of time usually between 2 and 10 minutes.

[0161] - The second stage of mechanical processing (referred to as the "preparation" stage), which is carried out in an open mixer (e.g., a two-roll mill) after cooling the mixture obtained during the first non-preparation stage to a lower temperature, usually less than 110 °C, e.g., between 40 °C and 100 °C. Then the crosslinking system is introduced and the combined mixture is mixed for several minutes (e.g., between 1 minute and 30 minutes).

[0162] The final composition thus obtained is then calendered into the form of, for example, sheets or slabs for use especially in laboratory characterization, or extruded into the form of rubber semi-finished products (or shaped elements) that can be used, for example, as the inner liner of a tire.

[0163] The composition can be in an uncured state (before crosslinking or vulcanization) or in a cured state (after crosslinking or vulcanization), or can be a semi-finished product capable of being used in a tire.

[0164] 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 minutes and 90 minutes.

[0165] The following examples are given by way of illustration and should not be construed as limiting the invention in any way.

[0166] Tire

[0167] According to the invention, the composition described above is particularly suitable for being introduced into at least one tire bead, preferably into two tire beads.

[0168] The bead of a tire, also known as the "bead area", is one of the three main areas of a tire (the crown, the sidewall and the bead).

[0169] More specifically, the bead is the portion of the tire intended to enable the tire to be attached to a mounting support, such as a wheel comprising a rim. Each bead is therefore particularly intended to come into contact with a flange of the rim, thereby allowing it to be attached. Thus, when the tire is inflated to its nominal pressure on a measuring rim, the bead may be radially defined on the inside by the radially innermost point of the tire and on the outside by the radially outermost point of the outer surface of the tire bead, in order to come into contact with the measuring rim of the tire according to the ETRTO (European Tire and Rim Technical Organization) 2021 standard manual.

[0170] In some embodiments, the tire includes a carcass reinforcement, which includes at least one carcass layer anchored in each bead, and the carcass layer is wound around the circumferential reinforcement element of each bead so that the axially inner portion of the carcass layer anchored in each bead is axially arranged on the inner side of the axially outer portion of the carcass layer anchored in each bead.

[0171] In these embodiments, due to winding therein, the bead is relatively subjected to the stress of the carcass reinforcement. Therefore, in order to ensure that the rubber composition has sufficient strength in these particularly stressed embodiments, the rubber composition generally comprises a variety of elastomers; specifically, it may comprise 25phr to 60phr of natural rubber and 40phr to 75phr of at least one polybutadiene. The content of the reinforcing filler of the composition is as described above. More specifically, in some embodiments, the composition comprises 60 to 90phr, preferably 60 to 80phr or 60 to 78phr of reinforcing filler, and the reinforcing filler is composed of a mixture of carbon black and pyrolytic carbon black. Therefore, preferably, the mixture comprises 30phr to 60phr of pyrolytic carbon black and 20phr to 40phr of carbon black.

[0172] In other embodiments, the tire includes a carcass reinforcement, which includes at least one carcass layer anchored in each bead, each bead including an axially inner circumferential reinforcement element and an axially outer circumferential reinforcement element, wherein the axially inner circumferential reinforcement element is axially arranged on the inner side of the carcass layer anchored in each bead, and the axially outer circumferential reinforcement element is axially arranged on the outer side of the carcass layer anchored in each bead.

[0173] In these other embodiments, the bead is relatively stress-free from the carcass reinforcement due to being anchored and not wound. Thus, in these other relatively stress-free embodiments, the rubber composition advantageously contains a higher proportion of natural rubber. Thus, the composition may comprise one or more elastomers, in particular 40 to 100 phr of natural rubber and 0 to 60 phr of at least one polybutadiene. The content of the reinforcing filler in the composition is as described above. More specifically, in some embodiments, the composition comprises 60 to 90 phr, preferably 60 to 80 phr or 60 to 78 phr of reinforcing filler, which consists of a mixture of carbon black and pyrolytic carbon black. Thus, preferably, the mixture comprises 30 phr to 60 phr of pyrolytic carbon black and 20 phr to 40 phr of carbon black.

[0174] In a particularly advantageous embodiment, the bead or each bead comprises a seating layer which is intended to come into contact with the mounting support of the tyre when the tyre is mounted on the mounting support, the seating layer comprising a rubber composition, preferably consisting of the rubber composition described above. The content of the reinforcing filler in the composition is as described above. More specifically, in some embodiments, the composition comprises 60 to 90 phr, preferably 60 to 80 phr or 60 to 78 phr of reinforcing filler, which consists of a mixture of carbon black and pyrolytic carbon black. Thus, preferably, the mixture comprises 30 phr to 60 phr of pyrolytic carbon black and 20 phr to 40 phr of carbon black.

[0175] Typically, the mounting support is a rim.

[0176] Regardless of the embodiments described above, the seating layer is arranged axially on the outside of the circumferential reinforcing element or each circumferential reinforcing element. Thus, when the tyre is mounted on the support, the seating layer is arranged axially between the circumferential reinforcing element or each circumferential reinforcing element and the mounting support.

[0177] As previously mentioned, a tyre, in particular a passenger vehicle tyre, generally comprises:

[0178] - two beads which are intended to come into contact with the mounting support;

[0179] - two sidewalls which extend radially outwards from the beads and converge in the crown, the crown comprising a tread and a crown reinforcement;

[0180] - at least one carcass reinforcement which extends radially in each sidewall, axially in the crown and radially on the inside of the crown reinforcement. BRIEF DESCRIPTION OF THE DRAWINGS

[0181] The invention will be better understood by reading the following description, which is given by way of non-limiting example only with reference to the accompanying drawings, in which:

[0182] - Figure 1 View in the meridian cross-sectional plane parallel to the tire rotation axis of a tire according to a first embodiment of the invention.

[0183] - Figure 2 For a tire according to a second embodiment, a view similar to Figure 1 the one shown. DETAILED DESCRIPTION

[0184] In the figures related to the tire, a reference system X, Y, Z is shown, which respectively corresponds to the usual axial direction (Y), radial direction (Z) and circumferential direction (X) of the tire.

[0185] In the figures related to the tire, a reference system X, Y, Z is shown, which respectively corresponds to the usual axial direction (Y), radial direction (Z) and circumferential direction (X) of the tire.

[0186] Figure 1 Shown is a tire according to a first embodiment of the invention, designated overall by reference numeral 10. The tire 10 has a generally toroidal shape about an axis of rotation substantially parallel to the axial direction Y. The tire 10 is intended for use on passenger vehicles.

[0187] The tire 10 includes a crown 12 and a crown reinforcement 16. The crown 12 includes a tread 14 intended to contact the ground during tire operation. The crown reinforcement 16 extends circumferentially in the crown 12 in the circumferential direction X. The tire 10 also includes an inner seal layer 18 that is sealed to the inflation gas and, once the tire 10 has been mounted on a mounting support (such as a rim), is intended to delimit, together with the mounting support of the tire 10, an inner cavity that is intended to be pressurized with the inflation gas.

[0188] The tire 10 includes two sidewalls 30 that extend radially inwardly from the crown 12. The tire 10 also includes two beads 32 that are located radially inside the sidewalls 30. Each bead 32 is intended to contact the mounting support. Each sidewall 30 connects each bead 32 to the crown 12. Thus, the two sidewalls 30 extend the beads 32 radially outwardly and converge in the crown 12. Each bead 32 is radially delimited on the inside by the radially innermost point 321 of the tire 1. Each bead 32 is radially delimited on the outside by the radially outermost point 322 of the outer surface SE of the bead 32, which, according to the ETRTO (European Tyre and Rim Technical Organization) Standard Manual 2021, will contact the tire's measuring rim (not shown) when the tire is inflated to its nominal pressure on this measuring rim. The radially innermost point 321 defines the radially inner end ERI of the bead 32, and the point 322 defines the radially outer end ERE of the bead 32.

[0189] The tire 10 includes a carcass reinforcement 34. A crown reinforcement 16 is arranged radially between the tread 14 and the carcass reinforcement 34. The carcass reinforcement 34 includes at least one carcass ply 36 anchored in each bead 32, which is a single carcass ply 36 in this example. The carcass ply 36 extends radially in each sidewall 30 and axially in the crown 12, and extends radially on the inner side of the crown reinforcement 16.

[0190] To anchor the carcass ply 36, the carcass ply 36 is anchored in each bead 32 by being wound around a circumferential reinforcement element 35 (a bead wire in this example) of each bead 32, such that the axial inner portion 361 of the carcass ply 36 anchored in each bead 32 is arranged axially inside the axial outer portion 362 of the carcass ply 36 anchored in each bead 32, and such that each axial end 363 of the carcass ply 36 anchored in each bead 32 is arranged radially outside each circumferential reinforcement element 35.

[0191] Each bead 32 includes a first layer 42 (referred to as a filler layer), which extends radially outward from each circumferential reinforcement element 35 and contacts the carcass ply 36. The first layer 42 is arranged to be at least partially located between the axial inner portion 361 and the axial outer portion 362.

[0192] Each bead 32 further includes a second layer 44, which is arranged axially outside the axial outer portion 362 and the outer side of the first filler layer 42.

[0193] Each bead 32 further includes a third layer 46, which is referred to as the seating layer of the tire 10. When the tire is mounted on the mounting support, the third seating layer 46 is intended to contact the mounting support of the tire 10. When the tire is mounted on the support, the third seating layer 46 is arranged axially outside the circumferential reinforcement element 35, more precisely axially between the circumferential reinforcement element 35 and the mounting support (not shown).

[0194] At least one of the first, second, and third layers 42, 44, 46 includes, preferably consists of, a rubber composition according to the present invention. In the illustrated embodiment, the third seating layer 46 consists of a rubber composition according to the present invention. Specifically, the rubber composition of the third seating layer 46 specifically contains a plurality of elastomers; specifically, it contains 25 phr to 60 phr of natural rubber and 40 phr to 75 phr of at least one polybutadiene.

[0195] Figure 2 A tire showing a second embodiment according to the present invention is shown. Elements similar to those shown in Figure 1 are denoted by the same reference numerals.

[0196] Unlike the tire according to the first embodiment, the tire 10 according to the second embodiment is such that, in order to anchor the carcass ply 36, the tire 10 includes an axially inner circumferential reinforcing element 38 and an axially outer circumferential reinforcing element 40, the axially inner circumferential reinforcing element 38 being arranged axially inside the carcass ply 36 and the axially outer circumferential reinforcing element 40 being arranged axially outside the carcass ply 36. Here, each of the reinforcing elements 38, 40 includes a continuous wire reinforcing element wound around a plurality of circumferential turns, as described in, for example, WO 2021 / 123522.

[0197] As in the first embodiment, at least one of the first, second and third plies 42, 44, 46 contains, preferably consists of, the rubber composition according to the invention. In the illustrated embodiment, the third ply 46 consists of the rubber composition according to the invention. Specifically, the rubber composition of the third ply 43 specifically contains one or more elastomers; specifically, it contains 40 phr to 100 phr of natural rubber and 0 phr to 60 phr of at least one polybutadiene.

[0198] The tire according to the invention is intended to equip motor vehicles of the passenger vehicle type, SUVs ("sport utility vehicles"), or two-wheeled vehicles (in particular motorcycles), or aircraft, or industrial vehicles selected from vans, heavy vehicles (i.e., subways, buses, heavy road transport vehicles (trucks, tractors, trailers) or off-road vehicles (such as 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, van and SUV types.

[0199] The following examples are given by way of illustration. In no case should they be considered as limiting the invention.

[0200] Examples

[0201] Measurement methods

[0202] Measurement of the tensile test:

[0203] The tensile test can determine the elastic modulus and the fracture properties, and they are based on the standard NF ISO37 of December 2005.

[0204] At 23 °C, at the second elongation (i.e., after the conditioning cycle at the elongation rate provided for the measurement itself), the nominal secant modulus (or apparent stress, in MPa, relative to the strain in dimensionless units) is measured at 10% elongation (denoted as MA10).

[0205] The tear index is measured at 23 °C. Specifically, the force applied to obtain a break (in N / mm) is determined, and the break strain (in %) is measured on a specimen measuring 10 × 85 × 2.5 mm, with 3 cuts 5 mm deep at the center of the specimen length, with the aim of breaking the specimen. Thus, the energy that causes the specimen to break can be determined, i.e., the product of the breaking force and the breaking strain.

[0206] The results are given on a scale of 100, i.e., these values are expressed relative to a control sample, the measured value of which is taken as the reference value of 100.

[0207] Thus, a lower breaking energy value indicates a decrease in tear strength performance (i.e., a decrease in breaking energy), while a higher value indicates better performance.

[0208] Dynamic properties:

[0209] The dynamic properties G * and tan(δ)max are measured on a viscometer (Metravib V A4000) according to the standard ASTM D 5992-96. According to the standard ASTM D 1349-99, the response of a sample of the vulcanized composition (cylindrical specimen with a thickness of 4 mm and a cross-sectional area of 400 mm 2 to a simple alternating sinusoidal shear stress at a frequency of 10 Hz is recorded under variable temperature conditions, specifically at 23 °C. A peak-to-peak strain amplitude sweep is carried out from 0.1% to 50% (outward cycle), then from 50% to 1% (return cycle). The results utilized are the complex dynamic shear modulus (G*) and the loss factor (tanδ). For the return cycle, the maximum value of the observed tanδ (tan(δ)max), as well as the difference in the complex modulus (ΔG * ) (Payne effect) between the values at 0.1% strain and 50% strain are shown.

[0210] The lower the value of tan(δ) at 23 °C, the lower the hysteresis of the composition, and thus the lower the rolling resistance.

[0211] The results in terms of performance are expressed on a scale of 100, i.e., the value 100 is arbitrarily assigned to the control sample in order to subsequently compare the tan(δ) (i.e., hysteresis, and thus rolling resistance) at 23 °C of the various tested formulations. The value on a scale of 100 is calculated according to the following operation: (tan(δ) value of the control sample at 23 °C / tan(δ) value of the sample at 23 °C) * 100. In this way, a lower value indicates a decrease in hysteresis performance (i.e., an increase in hysteresis), while a higher value indicates better hysteresis performance (i.e., lower hysteresis).

[0212] Preparation of the composition

[0213] The following tests were carried out in the following manner: The diene elastomer, reinforcing filler, and various other components except for the vulcanization system were successively introduced into a closed mixer (final filling degree: approximately 70% by volume), and the initial container temperature of the closed mixer was approximately 70 °C. Then, thermomechanical processing (non-preparation stage) was carried out in one step, which lasted for a total of approximately 3 to 4 minutes until a maximum "discharge" temperature of 165 °C was reached.

[0214] The mixture thus obtained was recovered and cooled, and then sulfur and an accelerator (sulfenamide) were added in a mixer (homogenizer) at 30 °C, and all substances were mixed for an appropriate time (for example, between 5 and 12 minutes) (preparation stage).

[0215] Subsequently, the composition thus obtained was calendered into a slab (thickness of 2 to 3 mm) or in the form of a rubber sheet, and then a curing step was carried out at 150 °C for 25 minutes, after which its physical or mechanical properties were measured.

[0216] Tests

[0217] Tests were carried out using the different rubber compositions shown in Tables 1 and 2, which were based on natural rubber or blends of natural rubber and polybutadiene.

[0218] Composition T1 corresponds to a conventional composition for forming a bead.

[0219] Compositions Ex1 to Ex6 correspond to the compositions used in the context of the present invention, where the contents of carbon black and pyrolytic carbon black are different, and the content of debris is also increasing.

[0220] Compositions Ex7 to Ex10 correspond to the compositions used in the context of the present invention, where the contents of carbon black and pyrolytic carbon black are different, and some contain debris while some do not.

[0221] Compositions Ex1 to Ex10 are advantageous compositions for use with tires according to the first embodiment described above.

[0222] Finally, Compositions Ex11 and Ex12 correspond to the compositions used in the context of the present invention, containing a blend of carbon black and pyrolytic carbon black, and debris with different contents of natural rubber and polybutadiene. Therefore, the latter compositions cannot be analyzed and compared with the control composition T1, but their performance can be proven to be superior to other elastomeric matrices.

[0223] Compositions Ex11 and Ex12 are advantageous compositions for use with tires according to the second embodiment described above.

[0224] Subsequently, in the cured state, i.e., after vulcanization, the elongation at break (EB), fracture energy, and tensile elastic modulus at 10% elongation (MA 10) and dynamic properties (G* and tan(δ)max at 10% elongation).

[0225] The properties of the compositions are shown in Tables 1 and 2.

[0226] Table 1: Formulations (contents in phr) and properties of compositions T1 and Ex1 to Ex6.

[0227]

[0228] (1) Natural rubber

[0229] (2) Polybutadiene

[0230] (3) Carbon black, ASTM N550 grade from Cabot; BET (according to ASTM D6556-10): 39 m 2 / g, COAN: 85 mL / 100 g

[0231] (4) Pyrolytic carbon black P550 from Scandinavian Enviro Systems (ash (%): 18.5; sulfur (%): 3; zinc (%): 4.5; STSA specific surface area: 56 m 2 / g (ASTM D6556-2021); void volume at 50 MPa: 44 mL / 100 g (ASTM D7854-21))

[0232] (5) PolyDyne crumb rubber – Lehigh; particle size distribution (according to ASTM D5644-01): < 12% on 60 mesh

[0233] (7) Oil resin

[0234] (8) 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-dihydroquinoline (TMQ from Lanxess))

[0235] (9) Varazon 4959 wax from Sasol

[0236] (10) Sulfur

[0237] (11) Pristerene 4931 stearic acid from Uniqema

[0238] (12) N-(tert-butyl)-2-benzothiazolesulfenamide (Santocure TBBS) from Flexsys

[0239] Industrial-grade zinc oxide obtained from Umicore

[0240] Table 2: Formulations (contents in phr) and properties of compositions T1 and Ex7 to Ex12

[0241]

[0242]

[0243] (1) Natural rubber

[0244] (2) Polybutadiene

[0245] (3) Carbon black, ASTM N550 grade obtained from Cabot; BET (according to ASTM D6556-10): 39 m 2 / g, COAN: 85 ml / 100 g

[0246] (4) Pyrolytic carbon black P550 obtained from Scandinavian Enviro Systems (ash (%): 18.5; sulfur (%): 3; zinc (%): 4.5; STSA specific surface area: 56 m 2 / g (ASTM D6556-2021); void volume at 50 MPa: 44 ml / 100 g (ASTM D7854-21))

[0247] (5) PolyDyne crumb rubber – Lehigh; particle size distribution (according to ASTM D5644-01): < 12% on 60 mesh

[0248] (6) Vivatec 500TDAE oil obtained from H&R

[0249] (7) Oil resin

[0250] (8) Combination of two antioxidants TMQ ((N-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine (Santoflex 6-PPD obtained from Flexsys) and 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ obtained from Lanxess))

[0251] (9) Varazon 4959 wax obtained from Sasol

[0252] (10) Sulfur

[0253] (11) Pristerene 4931 stearic acid obtained from Uniqema

[0254] (12) N-(tert-Butyl)-2-benzothiazolesulfenamide (Santocure TBBS) obtained from Flexsys

[0255] (13) Industrial grade zinc oxide obtained from Umicore

[0256] It can be observed that the compositions used in the context of the present invention (Ex 1 to Ex 10) have the same stiffness / hysteresis balance as the control composition (T1), and even a better stiffness / hysteresis balance in the case of Ex 1 to Ex 6, while having an improved tear fracture energy, reflecting better material cohesion and resistance to aggression.

Claims

1. A tire comprising two beads, wherein at least one bead comprises a rubber composition based on: - at least one elastomer; - 60 to 100 phr of reinforcing fillers, of which 15 to 70 phr is pyrolytic carbon black, 15 to 60 phr is carbon black, and the total content of carbon black and pyrolytic carbon black is 60 to 90 phr; and - Cross-linking system.

2. Tire according to the preceding claim, in, 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. A tyre according to any one of the preceding claims, in, The rubber composition comprises 25 to 100 phr of natural rubber and 0 to 75 phr of at least one polybutadiene.

4. A tyre according to any one of the preceding claims, in, The composition comprises 60 to 80 phr of a reinforcing filler consisting of a mixture of carbon black and pyrolytic carbon black.

5. Tire according to the preceding claim, in, The mixture of carbon black and thermal black comprises 20 to 40 phr of carbon black and 30 to 60 phr of thermal black.

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

7. A tyre according to any one of the preceding claims, in, The sulfur content of the pyrolytic carbon black is greater than 2 wt %, preferably in the range of 2.5 wt % to 5 wt %, relative to the total weight of the pyrolytic carbon black.

8. A tyre according to any one of the preceding claims, in, The composition also includes crumb rubber, preferably in an amount greater than 0 phr and less than or equal to 20 phr.

9. A tyre according to any one of the preceding claims, in, The crosslinking system is a vulcanization system based on molecular sulphur and / or sulphur donors; the vulcanization system preferably comprises between 0.5 and 10 phr of sulphur, preferably between 1 and 5 phr of sulphur.

10. The tire according to any one of the preceding claims, in, 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.

11. A tyre according to any one of claims 1 to 10, comprising a carcass reinforcement, the carcass reinforcement comprising at least one carcass layer anchored in each bead, the carcass layer being wound around the circumferential reinforcing element of each bead so that the axially inner portion of the carcass layer anchored in each bead is axially arranged on the inside of the axially outer portion of the carcass layer anchored in each bead.

12. Tire according to the preceding claim, in, The rubber composition comprises 25 phr to 60 phr of natural rubber and 40 phr to 75 phr of at least one polybutadiene.

13. The tire according to any one of claims 1 to 10, comprising a carcass reinforcement including at least one carcass ply anchored in each bead, each bead including an axially inner circumferential reinforcement element and an axially outer circumferential reinforcement element, the axially inner circumferential reinforcement element being arranged axially inside the carcass ply anchored in each bead, and the axially outer circumferential reinforcement element being arranged axially outside the carcass ply anchored in each bead.

14. The tire according to the preceding claim, wherein, the rubber composition comprises 40 phr to 100 phr of natural rubber and 0 phr to 60 phr of at least one polybutadiene.

15. The tire according to any one of the preceding claims, wherein, the bead or each bead includes a seating ply 46 which, when the tire is mounted on a mounting support, is intended to come into contact with the tire mounting support, the seating ply 46 comprising a rubber composition and preferably consisting of a rubber composition.

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