Tyre

Abstract

The present invention relates to a tyre comprising two beads, wherein at least one of the beads comprises a rubber composition based on: - at least one elastomer; - from 60 to 100 phr of reinforcing fillers, including from 15 to 70 phr of pyrolysis carbon black and from 15 to 60 phr of carbon black with a total content of carbon black and pyrolysis carbon black ranging from 60 to 90 phr; and - a crosslinking system.

Description

[0001] PNEUMATIC

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a tire, in particular for passenger vehicles.

[0004] TECHNOLOGICAL BACKGROUND

[0005] Passenger vehicle tires usually include:

[0006] - two beads intended to come into contact with a mounting support;

[0007] - two sidewalls extending the beads radially outwards and joining in a crown comprising a tread and a crown reinforcement;

[0008] - at least one carcass reinforcement extending radially in each sidewall and axially in the crown, radially internal to the crown reinforcement.

[0009] Each bead is made up of rubber compounds subjected to high stresses. They must therefore have a sufficient level of rigidity with good rolling resistance performance and be sufficiently cohesive to withstand external physical attacks, such as when fitting / removing tires.

[0010] In a constant effort to improve tires and reduce their environmental footprint, manufacturers aim to develop new rubber compositions that meet, among other things, the criteria set out above. One of the objectives of the present invention is thus to provide a tire whose beads have a good compromise between rigidity and tear resistance without compromising hysteresis and while incorporating a significant proportion of recycled material.

[0011] BRIEF DESCRIPTION OF THE INVENTION

[0012] The present invention relates to a tire comprising two beads, at least one of the beads comprising a rubber composition based on:

[0013] - at least one elastomer;

[0014] - 60 to 100 pce of reinforcing fillers, including 15 to 70 pce of pyrolysis carbon black and 15 to 60 pce of carbon black, with a total content of carbon black and pyrolysis carbon black ranging from 60 to 90 pce; and

[0015] - a crosslinking system.

[0016] Other aspects of the invention are as described below and in the claims. DEFINITIONS

[0017] The expression "composition based on" means a composition comprising the mixture and / or the in situ reaction product of the different constituents used, some of these constituents being able to react and / or being intended to react with each other, at least partially, during the different phases of manufacture of the composition; the composition can thus be in a totally or partially crosslinked state or in a non-crosslinked state.

[0018] By the expression "part by weight per hundred parts by weight of elastomer" (or pce), it is meant, within the meaning of the present invention, the part, by mass per hundred parts by mass of elastomer or rubber, the two terms being synonymous.

[0019] In this document, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0020] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the range of values ​​from more than a to less than b (i.e., excluding the limits a and b), while any interval of values ​​designated by the expression "from a to b" means the range of values ​​from a to b (i.e., including the strict limits a and b). In this document, when describing an interval of values ​​by the expression "from a to b", the interval represented by the expression "between a and b" is also and preferably described.

[0021] The term "radial" refers to a radius of the tire. In this sense, a point P1 is said to be "radially inward" of a point P2 (or "radially inward" of point P2) if it is closer to the tire's axis of rotation than point P2. Conversely, a point P3 is said to be "radially outward" of a point P4 (or "radially outward" of point P4) if it is further from the tire's axis of rotation than point P4. We say that we are moving "radially inward (or outward)" when we are moving toward smaller (or larger) radii. When talking about radial distances, this meaning of the term also applies.

[0022] By "radial cut" or "radial section" is meant here a cut or section along a plane which contains the axis of rotation of the tire.

[0023] An “axial” direction is a direction parallel to the tire’s axis of rotation. A point P5 is said to be “axially inboard” of a point P6 (or “axially inboard” of point P6) if it is closer to the tire’s median plane than point P6. Conversely, a point P7 is said to be “axially outboard of” a point P8 (or “axially outboard” of point P8) if it is further from the tire’s median plane than point P8. The tire’s “median plane” is the plane that is perpendicular to the tire’s axis of rotation and is equidistant from the annular reinforcement structures of each bead.

[0024] A “circumferential” direction is the direction which, in each meridian section plane, is perpendicular to both a radius of the tire and the axial direction. The carbon-containing compounds mentioned in the description may be of fossil or bio-sourced origin. In the latter case, they may be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass. This includes, in particular, polymers, plasticizers, fillers, etc.

[0025] DETAILED DESCRIPTION OF THE INVENTION

[0026] The inventors developed rubber compositions that met the expressed needs.

[0027] Thus, the present invention relates to a tire comprising two beads, at least one of the beads comprising a rubber composition based on:

[0028] - at least one elastomer;

[0029] - 60 to 100 pce of reinforcing fillers, including 15 to 70 pce of pyrolysis carbon black and 15 to 60 pce of carbon black with a total content of carbon black and pyrolysis carbon black ranging from 60 to 90 pce; and

[0030] - a crosslinking system.

[0031] The rubber composition may further comprise rubber crumb and / or usual additives and processing agents.

[0032] The various constituents of the rubber composition may be as described below.

[0033] Elastomer

[0034] The composition useful in the context of the present invention is based on at least one elastomer (or indistinctly rubber).

[0035] The or each elastomer may be chosen from the group consisting of diene elastomers and mixtures thereof.

[0036] By "diene" elastomer, whether natural or synthetic, is understood in a known manner an elastomer consisting at least in part (i.e., a homopolymer or a copolymer) of diene monomer units (monomers carrying two carbon-carbon double bonds, conjugated or not). These diene elastomers can be classified into two categories "essentially unsaturated" or "essentially saturated".In general, the term "essentially unsaturated" means a diene elastomer derived at least in part from conjugated diene monomers, having a content of units or patterns of diene origin (conjugated dienes) which is greater than 15% (mol %); thus, diene elastomers such as butyl rubbers or copolymers of dienes and alpha-olefins such as EPDM do not fall within the preceding definition and may be described in particular as "essentially saturated" diene elastomers (low or very low content of patterns of diene origin, always less than 15%).

[0037] The following are particularly understood to mean a diene elastomer that can be used:

[0038] (a) - any homopolymer obtained by polymerization of a diene monomer, conjugated or not, having from 4 to 18 carbon atoms;

[0039] (b) - any copolymer obtained by copolymerization of a diene, conjugated or not, having from 4 to 18 carbon atoms and at least one other monomer.

[0040] The other monomer can be ethylene, an olefin or a diene, conjugated or not.

[0041] Suitable conjugated dienes are conjugated dienes having 4 to 12 carbon atoms, in particular 1,3-dienes, such as 1,3-butadiene and isoprene.

[0042] Suitable olefins are vinylaromatic compounds with 8 to 20 carbon atoms and aliphatic α-monoolefins with 3 to 12 carbon atoms.

[0043] Suitable vinyl aromatic compounds are, for example, styrene, ortho-, meta-, para-methylstyrene, the commercial mixture "vinyl-toluene", para-tert-butylstyrene. Suitable aliphatic α-monoolefins are, in particular, acyclic aliphatic α-monoolefins having from 3 to 18 carbon atoms.

[0044] More particularly, the diene elastomer capable of being used in the compositions can be:

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

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

[0047] (c') - any copolymer obtained by copolymerization of one or more dienes, conjugated or not, with ethylene, an α-monoolefin or their mixture, such as for example elastomers obtained from ethylene, propylene with a non-conjugated diene monomer of the aforementioned type. Preferably, the diene elastomer is chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers. Butadiene copolymers are particularly chosen from the group consisting of butadiene-styrene copolymers (SBR).

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

[0049] Thus, the diene elastomer can be coupled and / or star-shaped, for example by means of a silicon or tin atom which links the elastomer chains together.

[0050] The diene elastomer may be simultaneously or alternatively functionalized and comprise at least one functional group. By functional group is meant a group comprising at least one heteroatom chosen from Si, N, S, O, P. Particularly suitable as functional groups are those comprising at least one function such as: silanol, an alkoxysilane, a primary, secondary or tertiary amine, cyclic or not, a thiol, an epoxide.

[0051] The rubber composition useful in the context of the invention may contain a single diene elastomer or a mixture of several diene elastomers.

[0052] In certain embodiments, the rubber composition useful in the context of the invention comprises one or more elastomers, it can thus comprise from 25 to 100 phr of natural rubber and from 0 to 75 phr of at least one polybutadiene, preferably from 35 to 75 phr of natural rubber and from 25 to 65 phr of at least one polybutadiene.

[0053] In certain embodiments, the rubber composition useful in the context of the invention comprises, as elastomer, a mixture of natural rubber (NR) and at least one polybutadiene (BR). Preferably, the mixture consists of 50 phr of natural rubber (NR) and 50 phr of polybutadiene (BR).

[0054] Reinforcing charge

[0055] The composition useful in the context of the present invention comprises from 60 to 100 pce of reinforcing fillers.

[0056] The term "reinforcing filler" means any type of filler known for its ability to reinforce a rubber composition that can be used in particular for the manufacture of tires, for example organic fillers such as carbon black or pyrolysis carbon black, or inorganic fillers such as silica or alumina. It is understood that rubber crumbs are not reinforcing fillers within the meaning of the present invention, and that any reinforcing fillers that they contain are not taken into account in the calculation of the total content of reinforcing fillers in the composition.

[0057] In particular, the composition useful in the context of the present invention comprises from 15 to 70 phr of pyrolysis carbon black and from 15 to 60 phr of carbon black with a total content of carbon black and pyrolysis carbon black ranging from 60 to 90 phr or from 60 to 80 phr or from 60 to 78 phr. The composition may therefore further comprise an inorganic reinforcing filler (e.g. silica or alumina) or an organic reinforcing filler other than carbon black and pyrolysis carbon black so as to achieve a total content of reinforcing fillers ranging from 60 to 100 phr. Below 60 phr of filler, the required level of rigidity is not achieved and above 100 phr of filler, industrial implementation is too difficult and the level of hysteresis is too high.

[0058] In certain embodiments, the composition comprises from 60 to 90 phr, preferably from 60 to 80 phr or from 60 to 78 phr, of reinforcing fillers, the reinforcing fillers consisting of a mixture of carbon black and pyrolysis carbon black. It should then be understood that the composition comprises as only reinforcing fillers carbon black and pyrolysis carbon black (the composition therefore does not comprise inorganic reinforcing fillers and other organic reinforcing fillers). Preferably, the mixture then comprises from 30 to 60 phr of pyrolysis black and from 20 to 40 phr of carbon black.

[0059] The reinforcing fillers may be as described below.

[0060] Pyrolysis carbon black

[0061] The composition useful in the context of the invention comprises from 15 to 70 pce of pyrolysis carbon black, preferably from 30 to 60 pce of pyrolysis carbon black.

[0062] For the purposes of the present invention, the term "pyrolysis carbon black" means a carbon black resulting from a process for pyrolyzing a material comprising at least one carbon polymer and a carbon black, hereinafter the material to be pyrolyzed, for example in the context of recycling such a material. The physical state in which the material to be pyrolyzed is present is indifferent, whether in the form of powder, granules, strips, or any other form, in the crosslinked or non-crosslinked state. Preferably, the material to be pyrolyzed can be recovered from manufactured articles or products generated during their manufacture / production (such as by-products or scrap); these manufactured articles can be chosen from the group consisting of pneumatic tires, non-pneumatic tires, industrial conveyor belts, transmission belts, rubber seals, rubber hoses, shoe soles and windshield wipers.More preferably still, the pyrolysis carbon black usable in the context of the present invention is a carbon black obtained from a pyrolysis process in which the material to be pyrolyzed comes from manufactured articles chosen from the group consisting of pneumatic tires and non-pneumatic tires.

[0063] Pyrolysis in the context of the present invention means any type of thermal decomposition in the absence of oxygen and whose raw material is the material to be pyrolyzed as defined above. Pyrolysis carbon blacks are therefore distinguished from so-called industrial and / or ASTM grade carbon blacks in that the carbon raw material used for pyrolysis is a material comprising at least one carbon polymer and one carbon black and not materials derived from petroleum fractions or from coal or from oils of natural origin.

[0064] The pyrolysis carbon blacks that can be used in the context of the present invention are distinguished from known carbon blacks such as industrial carbon blacks, in particular so-called “furnace” carbon blacks, in particular by a higher ash content.

[0065] Preferably, the pyrolysis carbon black usable in the context of the present invention has an ash content within a range from 5 to 30% by weight, more preferably from 8 to 25% by weight, more preferably still from 10% to 22% by weight, relative to the total weight of the pyrolysis carbon black.

[0066] Preferably, the pyrolysis carbon black usable in the context of the present invention has a sulfur content greater than 2% by weight, preferably 2.5 to 5% by weight, relative to the total weight of the pyrolysis carbon black.

[0067] Preferably, the pyrolysis carbon black usable in the context of the present invention has a zinc content greater than or equal to 2% by weight, preferably 2.5 to 8% by weight, relative to the total weight of the pyrolysis carbon black.

[0068] Preferably, the pyrolysis carbon black usable in the context of the present invention has a specific surface area STSA measured according to the ASTM D 6556-2021 standard within a range from 20 to 200 m 2 / g, more preferably ranging from 30 to 90 m 2 / g.

[0069] Preferably, the pyrolysis carbon black usable in the context of the present invention has a void volume measured according to standard ASTM D7854-21 and at a pressure of 50 MPa within a range from 30 to 60 ml / 100g, more preferably from 35 to 55 ml / 100g.

[0070] The ash content is determined by calcination in platinum capsules in a muffle furnace at 825°C according to the following protocol. A capsule is previously identified before each series of measurements and is tared to the nearest 0.1 mg and the mass is noted PO. In the capsule, 5 g of pyrolysis carbon black sample is introduced and weighed precisely to the nearest 0.1 mg; this mass is noted P1. The capsule and its contents are pre-calcined using a Bunsen burner until fumes appear and the product ignites. Once the product has completely burned, the capsule and its contents are introduced into a muffle furnace heated to 825 C for 1 h. After 1 h, the capsule is removed from the furnace and immediately placed in a desiccator at room temperature. When the capsule and the ash have returned to room temperature, the capsule is weighed again to obtain the mass P2.Finally, it is possible to obtain the ash content (% ash) using the formula below:.

[0071] The zinc content in the pyrolysis carbon black is determined after calcination of the sample, then recovery of the ash in an acid medium and determination by ICP-AES (inductively coupled plasma atomic emission spectroscopy). The ash is obtained by carrying out the protocol above. Approximately 100 mg of ash (test sample) is taken and placed in a PFA (perfluoroalkoxy) tube for a HotBIock hot plate. 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid and 0.5 mL of 40% hydrofluoric acid are then added. The tube is closed with its cap and heated at 130°C for 2 h. After cooling, the contents are then transferred using ultrapure water into a 100 mL PTFE (polytetrafluoroethylene) volumetric flask already containing 2 g of boric acid (to neutralize the hydrofluoric acid). The volume is topped up with ultrapure water to the mark.The solution obtained is diluted by 100, by taking 1 mL in a 100 mL PFTE flask, previously containing 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, 0.5 mL of 40% hydrofluoric acid and 2 g of boric acid. This diluted solution is then filtered through a 0.45 pm GHP syringe filter before being analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Before analyzing the diluted solution, at least 5 standards are analyzed by ICP-AES at zinc concentrations of 0, 0.5, 1, 2 and 5 mg / L. These standards were prepared in 100 mL volumetric flasks, by diluting a certified commercial solution to a zinc concentration of 1 g / L.

[0072] These volumetric flasks contain 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, 0.5 mL of 40% hydrofluoric acid and 2 g of boric acid. The standard solutions are analyzed by ICP-AES at a wavelength of λZn = 202.613 nm. For each standard concentration (c), the zinc signal intensity IZn is plotted on a graph IZn = f(c), which corresponds to the calibration line (of type y = ax + b). The sample solution (diluted solution) of unknown concentration is then measured under the same conditions as the standards. The measured intensity is related to the concentration using the calibration line obtained previously. The concentration [c]ash in % by mass is thus obtained directly by the software, because the test portion and the volume have been previously recorded. The zinc concentration in pyrolysis black [c]black in mass % is obtained by the following equation: 100% ash

[0073] The determination of the sulfur content in pyrolysis carbon blacks is carried out by LECO furnace. LECO sulfur analyzers are designed to measure, in particular, the sulfur content in organic and / or inorganic materials by combustion and non-dispersive infrared detection. Before measuring the sulfur content on the sample, the boats are cleaned and the furnace calibrated. The boats for LECO furnaces are previously cleaned: this involves analyzing the empty boat, under the same conditions as the samples. The preparation of the calibration curve is done from a commercial standard called "BBOT" whose purity is greater than 99.99% and whose carbon (C), hydrogen (H), nitrogen (N), oxygen (O) and sulfur (S) content is guaranteed. This content is as follows: C%: 72.52; H% 6.09; N% 6.51; 0% 7.43 and S% 7.44. Approximately 10 ± 3, 20 ± 3 and 40 ± 3 mg of BBOT are weighed exactly in a pod.The standard / boat assembly is introduced into the combustion furnace, regulated at 1350 °C under pure oxygen. The combination of the furnace temperature and the analysis flow rate causes the combustion of the sample and the release of sulfur and / or carbon in the form of SC>2(g). After a time of 20 s, oxygen begins to flow through the "lance" to accelerate the combustion of difficult-to-burn materials. The sulfur and / or carbon, in the form of SC>2(g), are carried by an oxygen flow through the infrared detection cells. The instrument software plots a straight line connecting the mass of standard introduced and the observed response (area) on the detector. This gives a calibration straight line. After carefully cleaning the sampling equipment, approximately 80 ± 5 mg of pyrolysis carbon black is weighed and introduced into a LECO tower boat.The observed SO2 peak area is related to the concentration using the calibration line. The instrument software then calculates the mass % of sulfur in the sample using the mass of the sample introduced into the basket.

[0074] Pyrolysis carbon blacks are marketed, for example, by the company BlackBear under the reference “BBCT30” or by the company Scandinavian Enviro Systems under the reference “P550”.

[0075] Carbon black

[0076] The composition useful in the context of the invention comprises from 15 to 60 pce of carbon black, preferably from 20 to 40 pce of carbon black.

[0077] All carbon blacks are suitable as carbon blacks, including blacks conventionally used in tires or their treads, in particular industrial carbon blacks, more specifically so-called "furnace" carbon blacks.

[0078] Among the carbon blacks, we will mention more particularly the reinforcing carbon blacks of the 100, 200, 300 series, or the 500, 600 or 700 series blacks (ASTM D-1765-2017 grades), such as for example blacks N115, N134, N234, N326, N330, N339, N347, N375, N550, N683, N772). Carbon blacks can be used in the isolated state, as commercially available, or in any other form, for example as a support for certain of the rubber additives used. Carbon blacks could for example already be incorporated into the diene elastomer, in particular isoprene in the form of a masterbatch (see for example applications WO 97 / 36724-A2 or WO 99 / 16600-A1). Reinforcing inorganic filler

[0079] The composition useful in the context of the invention may comprise a reinforcing inorganic filler.

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

[0081] Suitable reinforcing inorganic fillers are, in particular, mineral fillers of the siliceous type, preferably silica (SiC>2) or of the aluminous type, in particular alumina (AI2O3). The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET specific surface area and a CTAB specific surface area, both of less than 450 m 2 / g, preferably within a range of 30 to 400 m 2 / g, especially from 60 to 300 m 2 / g.

[0082] Any type of precipitated silica may be used, in particular highly dispersible precipitated silicas (called "HDS" for "highly dispersible" or "highly dispersible silica"). These precipitated silicas, whether highly dispersible or not, are well known to those skilled in the art. Examples include the silicas described in applications WO 03 / 016215-A1 and WO 03 / 016387-A1. Among the commercial HDS silicas, it is possible to use in particular the silicas "Ultrasil ® 5000GR", "Ultrasil ® 7000GR" from the company Evonik, the silicas "Zeosil ® 1085GR", "Zeosil® 1115 MP", "Zeosil® 1165MP", "Zeosil® Premium 200MP", "Zeosil® HRS 1200 MP" from the company Solvay.As non-HDS silica, the following commercial silicas can be used: silicas “Ultrasil ® VN2GR”, “Ultrasil ® VN3GR” from Evonik, silica “Zeosil® 175GR” from Solvay, silicas “Hi-Sil EZ120G(-D)”, “Hi-Sil EZ160G(- D)”, “Hi-Sil EZ200G(-D)”, “Hi-Sil 243LD”, “Hi-Sil 210”, “Hi-Sil HDP 320G” from PPG.

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

[0084] As other examples of inorganic fillers that may be used in the compositions, mention may also be made of mineral fillers of the aluminous type, in particular alumina (AI2O3), aluminum oxides, aluminum hydroxides, aluminosilicates, titanium oxides, silicon carbides or nitrides, all of the reinforcing type as described, for example, in applications WO 99 / 28376-A2, WO 00 / 73372-A1, WO 02 / 053634-A1, WO 2004 / 003067-A1, WO 2004 / 056915-A2, US 6,610,261-B1 and US 6,747,087-B2. Examples include the aluminas “Baikalox A125” or “CR125” (Baïkowski company), “APA-100RDX” (Condéa), “Aluminoxid C” (Evonik) or “AKP-G015” (Sumitomo Chemicals).

[0085] The physical state in which the reinforcing inorganic filler is presented is indifferent, whether in the form of powder, microbeads, granules, or even beads or any other suitable densified form. Of course, the term reinforcing inorganic filler also means mixtures of different reinforcing inorganic fillers, in particular silicas as described above.

[0086] Those skilled in the art will understand that, as a replacement for the reinforcing inorganic filler described above, a reinforcing filler of another nature could be used, provided that this reinforcing filler of another nature is covered with an inorganic layer such as silica, or else has functional sites on its surface, in particular hydroxyl sites, requiring the use of a coupling agent to establish the bond between this reinforcing filler and the diene elastomer. By way of example, mention may be made of carbon blacks partially or completely covered with silica, or carbon blacks modified with silica, such as, without limitation, the “Ecoblack®” type fillers of the CRX2000 series or the “CRX4000” series from Cabot Corporation.

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

[0088] To couple the reinforcing inorganic filler to the diene elastomer, it is possible to use, in a well-known manner, an at least bifunctional coupling agent (or bonding agent) intended to ensure a sufficient connection, of a chemical and / or physical nature, between the inorganic filler (surface of its particles) and the diene elastomer. In particular, at least bifunctional organosilanes or polyorganosiloxanes are used. By "bifunctional", we mean a compound having a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the diene elastomer.For example, such a bifunctional compound may comprise a first functional group comprising a silicon atom, said first functional group being capable of interacting with the hydroxyl groups of an inorganic filler and a second functional group comprising a sulfur atom, said second functional group being capable of interacting with the diene elastomer.

[0089] Preferably, the organosilanes are chosen from the group consisting of polysulfurized organosilanes (symmetrical or asymmetrical) such as bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated to TESPT, marketed under the name “Si69” by the company Evonik or bis-(triethoxysilylpropyl) disulfide, abbreviated to TESPD, marketed under the name “Si75” by the company Evonik, polyorganosiloxanes, mercaptosilanes, blocked mercaptosilanes, such as S-(3-(triethoxysilyl)propyl) octanethioate marketed by the company Momentive under the name “NXT Silane”. More preferably, the organosilane is a polysulfurized organosilane.

[0090] The skilled person can find examples of coupling agent in the following documents: WO 02 / 083782, WO 02 / 30939, WO 02 / 31041, WO 2007 / 061550, WO 2006 / 125532, WO 2006 / 125533, WO 2006 / 125534, US 6,849,754, WO 99 / 09036, WO 2006 / 023815, WO 2007 / 098080, WO 2010 / 072685 and WO 2008 / 055986.

[0091] The coupling agent content preferably represents from 0.5% to 15% by weight relative to the amount of reinforcing inorganic filler, preferably from 4 to 12%, more preferably from 6 to 10% by weight relative to the amount of reinforcing inorganic filler. Typically, the coupling agent level is less than 20 phr, preferably within a range from 6 to 17 phr, preferably from 8 to 15 phr. This level can easily be adjusted by a person skilled in the art according to the level of inorganic filler used in the composition.

[0092] The composition may also contain, in addition to the coupling agents, coupling activators, agents for covering inorganic fillers or more generally processing aids capable, in a known manner, thanks to an improvement in the dispersion of the filler in the rubber matrix and a reduction in the viscosity of the compositions, of improving their processability in the raw state, these agents being, for example, hydrolyzable silanes such as alkylalkoxysilanes (in particular alkyltriethoxysilanes), polyols, polyethers (for example polyethylene glycols), primary, secondary or tertiary amines (for example trialkanol-amines), hydroxylated or hydrolyzable POS, for example α,co-dihydroxy-polyorganosiloxanes (in particular α,co-dihydroxy-polydimethylsiloxanes), fatty acids such as, for example, stearic acid.

[0093] Other organic loads

[0094] Examples of organic fillers other than carbon blacks and pyrolysis carbon blacks include functionalized polyvinyl organic fillers as described in applications WO 2006 / 069792-A1, WO 2006 / 069793-A1, WO 2008 / 003434-A1 and WO 2008 / 003435-A1.

[0095] Rubber powder

[0096] The composition useful in the context of the invention may comprise rubber crumb (abbreviated as “crumb” in the following). Thus, the composition typically comprises from 0 to 20 pce of rubber crumb.

[0097] In some embodiments, the composition does not include rubber crumb.

[0098] In some embodiments, the composition comprises rubber crumbs having a content in the composition greater than 0 phr and less than or equal to 20 phr, for example 1 to 20 phr or 10 to 20 phr.

[0099] The crumb is in the form of granules, possibly formed into a rubber slab. Most often, rubber crumbs are produced by grinding or micronizing cooked rubber compositions already used for a first application, for example in tires; they are a product of recycled materials. The crumb is therefore preferably made up of a composition based on at least one elastomer and a filler. Preferably, the crumb is in the form of microparticles.

[0100] By "microparticles" is meant particles which have a size, namely their diameter in the case of spherical particles or their largest dimension in the case of anisometric particles, of a few tens or hundreds of microns. The crumbs are preferably made up of a composition based on an elastomer and a filler. They may also comprise all the ingredients usually used in rubber compositions such as plasticizers, antioxidants, vulcanization additives, etc. Thus, the crumb comprises an elastomer, preferably a diene elastomer. This elastomer preferably represents at least 30% by mass, more preferably at least 35% by mass, even more preferably at least 45% by mass of the weight of the crumb, a percentage determined according to standard ASTM E1 131.It is preferably chosen from the group consisting of polybutadienes, polyisoprenes including natural rubber, butadiene copolymers and isoprene copolymers. More preferably the molar rate of units of diene origin (conjugated dienes) present in the diene elastomer is greater than 50%, preferably between 50% and 70%.

[0101] According to a preferred embodiment of the invention, the powder contains between 5 and 80% by mass of filler, more preferably between 10% and 75%, and very preferably between 15% and 70%.

[0102] By filler is meant here any type of filler, whether it is reinforcing (typically with nanometric particles, and preferably with a weight average size of less than 500 nm, in particular between 20 and 200 nm) or whether it is non-reinforcing or inert (typically with micrometric particles, and preferably with a weight average size of greater than 1 μm, for example between 2 and 200 μm). The weight average size of the nanometric particles is measured in a manner well known to those skilled in the art (for example, according to application WO 2009 / 083160 paragraph 1.1). The weight average size of the micrometric particles can be determined by mechanical sieving.

[0103] Examples of fillers known to those skilled in the art as reinforcing include carbon black or a reinforcing inorganic filler such as silica or alumina in the presence of a coupling agent, or mixtures thereof. According to a preferred embodiment of the invention, the powder comprises, as filler, a reinforcing filler, in particular a carbon black or a mixture of carbon blacks.

[0104] The carbon black or the mixture of carbon blacks preferably represents more than 50%, more preferably more than 80%, even more preferably more than 90% by mass of the weight of the reinforcing filler of the powder. According to a more preferred embodiment, the reinforcing filler consists of a carbon black or a mixture of carbon blacks.

[0105] Very preferably, the carbon black is present in the crumb at a rate ranging from 20 to 40% by mass, more preferably from 25 to 35% by mass. All carbon blacks are suitable as carbon blacks, in particular blacks of the HAF, ISAF, SAF, FF, FEF, GPF and SRF type conventionally used in rubber compositions for tires (so-called tire-grade blacks). The crumb may contain all the other usual additives that are included in a rubber composition, in particular for tires. Among these usual additives, we can cite liquid or solid plasticizers, non-reinforcing fillers such as chalk, kaolin, protective agents, vulcanizing agents. These additives may also be found in the crumb in the form of residue or derivative, since they may have reacted during the stages of manufacturing the composition or crosslinking the composition from which the crumb is derived.

[0106] Concerning the constituents of the powder, it is preferred for the purposes of the invention that the powder has an acetone extract of between 3 and 30% by mass, more preferably in a range from 5 to 25% by mass.

[0107] Also, it is preferable that the powder has a chloroform extract of between 5 and 85% by mass, more preferably in a range of 5 to 50% by mass.

[0108] The crumbs can be simple ground rubber / micronisates, without any further treatment. It is also known that these crumbs can undergo treatment to modify them. This treatment can consist of a chemical modification of functionalization or devulcanization. It can also be a thermomechanical, thermochemical, biological treatment, etc.

[0109] Grinding can be carried out using various technologies, including cryogenic impact micronization technologies that allow the production of small particles on rubber materials. Commercial equipment such as the CUM150 mills from Netzsch or the CW250 mills from Alpine can be used.

[0110] According to a first embodiment of the invention, it is preferred to use a powder which has a morphology modified by thermal and / or mechanical, and / or biological and / or chemical treatment.

[0111] According to this first embodiment, it is preferred that the powder has an acetone extract of between 5 and 20% by mass, more preferably in a range from 10 to 18% by mass. Also, it is preferred that the powder has a chloroform extract of between 15 and 85% by mass, more preferably in a range from 15 to 50% by mass. Preferably, the chloroform extract of the rubber powder has a mass-average molecular mass (Mw) greater than 10,000 g / mol, preferably greater than 20,000 g / mol and more preferably greater than 30,000 g / mol.

[0112] According to the first embodiment, it is preferred that the ratio of the chloroform extract to the acetone extract, expressed as a mass percentage, is greater than or equal to 1.5; preferably greater than 2.

[0113] Preferably also according to this first embodiment, the powder has a Mooney viscosity (conventionally expressed in Mooney units, MU) of between 40 and 90, preferably between 45 and 75 and more preferably between 50 and 70.

[0114] According to a second embodiment of the invention, it is possible to use a powder which has not undergone any modification by thermal and / or mechanical, and / or biological and / or chemical treatment.

[0115] According to this second embodiment, it is preferred that the powder has an acetone extract of between 3 and 15% by mass, more preferably in a range from 3 to 10% by mass. Also, it is preferred that the powder has a chloroform extract of between 3 and 20% by mass, more preferably in a range from 5 to 15% by mass. Preferably, the chloroform extract of the rubber powder has a mass-average molecular weight (Mw) of less than 10,000 g / mol, preferably less than 8,000 g / mol. According to the second embodiment, it is preferred that the ratio of the chloroform extract to the acetone extract, expressed as a mass percentage, is less than 1.5.

[0116] Preferably also according to this second embodiment, the powder has an average particle size (D50) of between 10 and 400 pm, preferably between 50 and 350 pm and more preferably between 70 and 300 pm. Rubber powders useful for the purposes of the invention are commercially available, for example under the trade name “PolyDyne” marketed by the company Lehigh Technologies.

[0117] Crosslinking system

[0118] The composition useful in the context of the invention comprises a crosslinking system.

[0119] 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 in particular be based on sulfur, and / or peroxide and / or bismaleimides.

[0120] Preferably, the crosslinking system is sulfur-based, in which case it is referred to as a vulcanization system. The sulfur can be provided in any form, in particular in the form of molecular sulfur, or a sulfur-donating agent. At least one vulcanization accelerator is also preferably present, and, optionally, also preferably, various known vulcanization activators can be used, such as zinc oxide, stearic acid or equivalent compounds such as stearic acid salts and transition metal salts, guanidine derivatives (in particular diphenylguanidine), or even known vulcanization retarders.

[0121] Sulfur is used at a preferential rate of between 0.5 and 10 pce, particularly between 1 and 5 pce. The vulcanization accelerator is used at a preferential rate of between 0.5 and 10 pce, more preferably between 0.5 and 5.0 pce.

[0122] Any compound capable of acting as an accelerator for the vulcanization of diene elastomers in the presence of sulfur may be used as an accelerator, in particular accelerators of the thiazole type and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. Examples of such accelerators include, but are not limited to, the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated as "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-tert-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-tert-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds.

[0123] Common additives and implementing agents

[0124] The composition useful in the context of the invention may also comprise all or part of the usual additives and processing agents, known to those skilled in the art and usually used in rubber compositions for tires, such as for example plasticizers (such as plasticizing oils and / or plasticizing resins - whether or not having a tackifying character), non-reinforcing fillers, pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents, reinforcing resins (as described for example in application WO 02 / 10269).

[0125] In certain embodiments, the composition useful in the context of the invention comprises a plasticizer. The plasticizer content is then greater than 0 and less than or equal to 10 phr, for example from 1 to 5 phr.

[0126] The plasticizer is preferably chosen from hydrocarbon resins, plasticizing oils, and mixtures thereof. Particularly suitable are plasticizing oils chosen from the group consisting of naphthenic oils (low or high viscosity, in particular hydrogenated or not), paraffinic oils, MES oils (Medium Extracted Solvates), TDAE oils (Treated Distillate Aromatic Extracts), RAE oils (Residual Aromatic Extract oils), TRAE oils (Treated Residual Aromatic Extract) and SRAE oils (Safety Residual Aromatic Extract oils), mineral oils, vegetable oils, ether plasticizers, ester plasticizers, phosphate plasticizers, sulfonate plasticizers and mixtures of these compounds.

[0127] Hydrocarbon resins, also called hydrocarbon plasticizing resins, are polymers well known to those skilled in the art, essentially based on carbon and hydrogen but which may contain other types of atoms, for example oxygen, which can be used in particular as plasticizing agents or tackifying agents in polymer matrices. They are by nature at least partially miscible (i.e., compatible) at the rates used with the polymer compositions for which they are intended, so as to act as true diluting agents. They have been described for example in the work entitled "Hydrocarbon Resins" by R. Mildenberg, M. Zander and G. Collin (New York, VCH, 1997, ISBN 3-527-28617-9) of which chapter 5 is devoted to their applications, in particular in pneumatic rubber (5.5. "Rubber Tires and Mechanical Goods").As is known, these hydrocarbon resins can also be described as thermoplastic resins in the sense that they soften upon heating and can thus be molded.

[0128] The softening point of hydrocarbon resins is measured according to ISO 4625 ("Ring and Bail" method). The Tg is measured according to ASTM D3418 (1999). The macrostructure (Mw, Mn and Ip) of the hydrocarbon resin is determined by size exclusion chromatography (SEC): tetrahydrofuran solvent; temperature 35°C; concentration 1 g / l; flow rate 1 ml / min; solution filtered through a 0.45 pm porosity filter before injection; Moore calibration with polystyrene standards; set of 3 "WATERS" columns in series ("STYRAGEL" HR4E, HR1 and HR0.5); detection by differential refractometer ("WATERS 2410") and its associated operating software ("WATERS EMPOWER").

[0129] Hydrocarbon resins can be aliphatic, or aromatic or of the aliphatic / aromatic type, i.e. based on aliphatic and / or aromatic monomers. They can be natural or synthetic, based on petroleum or not (if this is the case, also known as petroleum resins). Suitable aromatic monomers include, for example, styrene, alpha-methylstyrene, indene, ortho-, meta-, para-methylstyrene, vinyl toluene, para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, any vinylaromatic monomer from a C9 fraction (or more generally from a C8 to C10 fraction). Preferably, the vinylaromatic monomer is styrene or a vinylaromatic monomer from a C9 cut (or more generally from a C8 to C10 cut). Preferably, the vinylaromatic monomer is the minority monomer, expressed as a molar fraction, in the copolymer considered.

[0130] According to a particularly preferred embodiment, the hydrocarbon plasticizing resin is chosen from the group consisting of cyclopentadiene (abbreviated CPD) or dicyclopentadiene (abbreviated DCPD) homopolymer or copolymer resins, terpene homopolymer or copolymer resins, terpene phenol homopolymer or copolymer resins, C5 cut homopolymer or copolymer resins, C9 cut homopolymer or copolymer resins, alpha-methyl-styrene homopolymer and copolymer resins and mixtures of these resins.

[0131] The term "terpene" here includes, in a known manner, the monomers alpha-pinene, beta-pinene and limonene; the limonene monomer being present, in a known manner, in the form of three possible isomers: L-limonene (levorotatory enantiomer), D-limonene (dextrorotatory enantiomer), or dipentene, the racemate of the dextrorotatory and levorotatory enantiomers. Among the above hydrocarbon plasticizing resins, mention will be made in particular of homo- or copolymer resins of alphapinene, betapinene, dipentene or polylimonene.

[0132] As is known, high Tg hydrocarbon resins are thermoplastic hydrocarbon resins with a Tg greater than 20°C.

[0133] Preferably, the plasticizing resin is a high Tg hydrocarbon plasticizing resin having at least one of the following characteristics: a Tg greater than 30°C; a number-average molecular weight (Mn) of between 300 and 2000 g / mol, more preferably between 400 and 1500 g / mol; a polydispersity index (Ip) of less than 3, more preferably less than 2 (reminder: Ip = Mw / Mn with Mw being the weight-average molecular weight). More preferably, this high Tg hydrocarbon plasticizing resin has all of the above preferred characteristics.

[0134] The above preferred high Tg hydrocarbon resins are well known to those skilled in the art and commercially available, for example sold with regard to: polylimonene resins: by the company DRT under the name "Dercolyte L120" (Mn=625 g / mol; Mw=1010 g / mol; lp=1.6; Tg=72°C) or by the company ARIZONA under the name "Sylvagum TR7125C" (Mn=630 g / mol; Mw=950 g / mol; lp=1.5; Tg=70°C); 05-cut / vinylaromatic copolymer resins, in particular 05-cut / styrene or 05-cut / 09-cut: by Neville Chemical Company under the names "Super Nevtac 78", "Super Nevtac 85" or "Super Nevtac 99", by Goodyear Chemicals under the name "Wingtack Extra", by Kolon under the names "Hikorez T1095" and "Hikorez T1100", by Exxon under the names "Escorez 2101" and "Escorez 1273";limonene / styrene copolymer resins: by DRT under the name "Dercolyte TS 105" from DRT, by ARIZONA Chemical Company under the names "ZT 115LT" and "ZT5100".;

[0135] Examples of other preferred resins include phenol-modified alpha-methyl-styrene resins. To characterize these phenol-modified resins, it is recalled that a so-called "hydroxyl index" (measured according to ISO 4326 standard and expressed in mg KOH / g) is used in a known manner. Alpha-methyl-styrene resins, in particular phenol-modified ones, are well known to those skilled in the art and are commercially available, for example sold by Arizona Chemical under the names "Sylvares SA 100" (Mn = 660 g / mol; Ip = 1.5; Tg = 53°C); "Sylvares SA 120" (Mn = 1030 g / mol; Ip = 1.9; Tg = 64°C); "Sylvares 540" (Mn = 620 g / mol; Ip = 1.3; Tg = 36°C; hydroxyl number = 56 mg KOH / g); "Silvares 600" (Mn = 850 g / mol; Ip = 1.4; Tg = 50°C; hydroxyl number = 31 mg KOH / g).

[0136] We can also cite resins from the alkyl-phenol family such as octylphenyl formaldehyde (OPF) available for example under the name "SP 1068" from the company SI Group as well as gem rosin resins such as those supplied for example by the company Costa Irmaos. Manufacture of compositions

[0137] The rubber composition useful in the context of the invention is manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art:

[0138] - a first phase of working or thermomechanical mixing (so-called "non-productive" phase), which can be carried out in a single thermomechanical step during which all the necessary constituents, in particular the elastomeric matrix, the fillers, any other various additives, with the exception of the crosslinking system, are introduced into a suitable mixer such as a conventional internal mixer (for example of the 'Banbury' type). The incorporation of the filler into the elastomer can be carried out in one or more stages by thermomechanical mixing.In the case where the filler is already incorporated in whole or in part into the elastomer in the form of a masterbatch as described for example in applications WO 97 / 36724 or WO 99 / 16600, it is the masterbatch which is directly mixed and where appropriate the other elastomers or fillers present in the composition which are not in the form of a masterbatch are incorporated, as well as any other various additives other than the crosslinking system.

[0139] The non-productive phase is carried out at high temperature, up to a maximum temperature of between 130°C and 170°C, for a duration generally of between 2 and 10 minutes.

[0140] - a second mechanical working phase (so-called "productive" phase), which is carried out in an external mixer such as a roller mixer, after cooling the mixture obtained during the first non-productive phase to a lower temperature, typically below 110°C, for example between 40°C and 100°C. The crosslinking system is then incorporated, and everything is then mixed for a few minutes, for example between 1 and 30 min.

[0141] The final composition thus obtained is then calendered, for example, in the form of a sheet or plate, in particular for characterization in the laboratory, or extruded in the form of a semi-finished (or profiled) rubber usable, for example, as an internal layer in a tire.

[0142] The composition may be either in the raw state (before crosslinking or vulcanization), or in the cured state (after crosslinking or vulcanization), may be a semi-finished product which may be used in a tire. The crosslinking of the composition may 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 may vary for example between 5 and 90 min. The examples which follow are given for illustrative purposes, but should in no case be considered as limiting the present invention.

[0143] TIRES

[0144] The compositions described above are, in accordance with the invention, particularly useful for inclusion in at least one of the beads of the tire and preferably in both beads of the tire.

[0145] The bead of a tire, referred to in English as the “Bead Zone,” is one of the three main zones of a tire (crown, sidewall, and bead).

[0146] More specifically, the bead is the portion of the tire intended to allow the tire to be attached to a mounting support, for example a wheel comprising a rim. Thus, each bead is in particular intended to be in contact with a hook of the rim allowing it to be attached. Thus, the bead can be radially delimited on the inside by the radially innermost point of the tire and radially delimited on the outside by the point of the external surface of the tire bead radially outermost to be in contact with a measuring rim of the tire according to the ETRTO (in English, "European Tire and Rim Technical Organization") standard manual, 2021 when the tire is inflated to its nominal pressure on this measuring rim.

[0147] In some embodiments, the tire comprises a carcass reinforcement comprising at least one carcass layer anchored in each bead forming a wrap around a circumferential reinforcing element of each bead such that an axially inner portion of the carcass layer anchored in each bead is arranged axially inside an axially outer portion of the carcass layer anchored in each bead.

[0148] In these embodiments, the bead is relatively stressed by the carcass reinforcement due to the winding that it forms there. Thus, in order to ensure sufficient strength of the rubber composition in these particularly stressful embodiments, the rubber composition typically comprises several elastomers, in particular it may comprise from 25 to 60 phr of natural rubber and from 40 to 75 phr of at least one polybutadiene. The content of reinforcing fillers in the composition is as described above. More particularly, in certain embodiments, the composition comprises from 60 to 90 phr, preferably from 60 to 80 phr or from 60 to 78 phr, of reinforcing fillers, the reinforcing fillers consisting of a mixture of carbon black and pyrolysis carbon black. Preferably, the mixture then comprises 30 to 60 pce of pyrolysis black and 20 to 40 pce of carbon black.

[0149] In other embodiments, the tire comprises a carcass reinforcement comprising at least one carcass layer anchored in each bead, each bead comprises an axially inner circumferential reinforcing element arranged axially inside the carcass layer anchored in each bead and an axially outer circumferential reinforcing element arranged axially outside the carcass layer anchored in each bead.

[0150] In these other embodiments, the bead is relatively little stressed by the carcass reinforcement due to its anchoring without winding. Thus, the rubber composition in these other low-stress embodiments advantageously comprises a higher proportion of natural rubber. The composition may thus comprise one or more elastomers, in particular from 40 to 100 phr of natural rubber and from 0 to 60 phr of at least one polybutadiene. The content of reinforcing fillers in the composition is as described above. More particularly, in certain embodiments, the composition comprises from 60 to 90 phr, preferably from 60 to 80 phr or from 60 to 78 phr, of reinforcing fillers, the reinforcing fillers consisting of a mixture of carbon black and pyrolysis carbon black. Preferably, the mixture then comprises 30 to 60 pce of pyrolysis black and 20 to 40 pce of carbon black.

[0151] In particularly advantageous embodiments, the or each bead comprises a tire base layer intended to be in contact with a tire mounting support when the tire is mounted on the mounting support, the base layer comprising the rubber composition, preferably consisting of the rubber composition described above. The reinforcing filler content of the composition is as described above. More particularly, in certain embodiments, the composition comprises from 60 to 90 phr, preferably from 60 to 80 phr or from 60 to 78 phr, of reinforcing fillers, the reinforcing fillers consisting of a mixture of carbon black and pyrolysis carbon black. Preferably, the mixture then comprises from 30 to 60 phr of pyrolysis black and from 20 to 40 phr of carbon black.

[0152] Typically, the mounting bracket is a rim.

[0153] Regardless of the embodiment described above, the seating layer is arranged axially outside the or each circumferential reinforcing element. The seating layer is therefore arranged axially between the or each circumferential reinforcing element and the mounting support when the tire is mounted on this support.

[0154] As previously stated, tires, especially for passenger vehicles, usually include:

[0155] - two beads intended to come into contact with a mounting bracket;

[0156] - two sidewalls extending the beads radially outwards and joining in a crown comprising a tread and a crown reinforcement;

[0157] - at least one carcass reinforcement extending radially in each sidewall and axially in the crown, radially internal to the crown reinforcement.

[0158] The invention will be better understood upon reading the following description, given solely as a non-limiting example and with reference to the drawings in which:

[0159] - figure 1 is a view, in a meridian section plane parallel to the axis of rotation of the tire, of a tire according to a first embodiment, and

[0160] - figure 2 is a view similar to that of figure 1 of a tire according to a second embodiment.

[0161] In the figures relating to the tire, a reference X, Y, Z is shown corresponding to the usual axial (Y), radial (Z) and circumferential (X) directions of a tire.

[0162] In the figures relating to the tire, a reference X, Y, Z is shown corresponding to the usual axial (Y), radial (Z) and circumferential (X) directions of a tire.

[0163] Figure 1 shows a tire, according to a first embodiment of the invention and designated by the general reference 10. The tire 10 has a substantially toric shape around an axis of revolution substantially parallel to the axial direction Y. The tire 10 is intended for a passenger vehicle. The tire 10 comprises a crown 12 comprising a tread 14 intended to come into contact with a ground during rolling and a crown reinforcement 16 extending in the crown 12 in the circumferential direction X. The tire 10 also comprises an internal sealing layer 18 to an inflation gas being intended to delimit an internal cavity with a mounting support of the tire 10 once the tire 10 is mounted on the mounting support, for example a rim, this cavity being intended to be pressurized by the inflation gas.

[0164] The tire 10 comprises two sidewalls 30 extending the crown 12 radially inwards. The tire 10 further comprises two beads 32 radially inwards to the sidewalls 30. Each bead 32 is intended to come into contact with a mounting support. Each sidewall 30 connects each bead 32 to the crown 12. Thus, the two sidewalls 30 extending the beads 32 radially outwardly and unite in the crown 12. Each bead 32 is delimited radially on the inside by the radially innermost point 321 of the tire 1. Each bead 32 is delimited radially on the outside by the point 322 of the outer surface SE of the radially outermost bead 32 to be in contact with a measuring rim (not shown) of the tire according to the ETRTO (European Tire and Rim Technical Organization) standard manual, 2021 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.

[0165] The tire 10 comprises a carcass reinforcement 34. The crown reinforcement 16 is arranged radially between the tread 14 and the carcass reinforcement 34. The carcass reinforcement 34 comprises at least one carcass layer 36, here a single carcass layer 36, anchored in each bead 32. The carcass layer 36 extends radially in each sidewall 30 and axially in the crown 12, radially inside the crown reinforcement 16.

[0166] For the purpose of anchoring the carcass layer 36, the carcass layer 36 is anchored in each bead 32 by forming a winding around a circumferential reinforcing element 35 of each bead 32, here a bead wire, such that an axially inner portion 361 of the carcass layer 36 anchored in each bead 32 is arranged axially inside an axially outer portion 362 of the carcass layer 36 anchored in each bead 32 and such that each axial end 363 axially delimiting the carcass layer 36 anchored in each bead 32 is arranged radially outside each circumferential reinforcing element 35.

[0167] Each bead 32 comprises a first layer 42, called a filler layer, extending radially outwards from each circumferential reinforcing element 35 and in contact with the carcass layer 36. The first layer 42 is arranged at least in part between the axially inner portion 361 and the axially outer portion 362.

[0168] Each bead 32 also comprises a second layer 44, arranged axially outside the axially outer portion 362 and the first filling layer 42.

[0169] Each bead 32 also comprises a third layer 46, called the base layer of the tire 10. The third base layer 46 is intended to be in contact with the mounting support of the tire 10 when the tire is mounted on this mounting support. The third base layer 46 is arranged axially outside the circumferential reinforcement element 35 and more precisely axially between the circumferential reinforcement element 35 and the mounting support (not shown) when the tire is mounted on this support.

[0170] At least one of the first, second and third layers 42, 44, 46 comprises, preferably consists of, a rubber composition in accordance with the invention. In the example illustrated, the third seat layer 46 consists of a rubber composition in accordance with the invention. In particular, the rubber composition of the third seat layer 46 comprises in particular several elastomers, in particular it comprises from 25 to 60 phr of natural rubber and from 40 to 75 phr of at least one polybutadiene.

[0171] Figure 2 shows a tire according to a second embodiment of the invention. Elements similar to those illustrated in Figure 1 are designated by identical references.

[0172] Unlike the tire according to the first embodiment, the tire 10 according to the second embodiment is such that, for the purpose of anchoring the carcass layer 36, the tire 10 comprises an axially inner circumferential reinforcing element 38 arranged axially inside the carcass layer 36 and an axially outer circumferential reinforcing element 40 arranged axially outside the carcass layer 36. Here each reinforcing element 38, 40 comprises a continuous wire reinforcing element wound over several circumferential turns, for example as described in WO 2021 / 123522. As for the first embodiment, at least one of the first, second and third layers 42, 44, 46 comprises, preferably is constituted by, a rubber composition according to the invention.In the illustrated example, the third seat layer 46 is made of a rubber composition in accordance with the invention. In particular, the rubber composition of the third seat layer 43 comprises in particular one or more elastomers, in particular it comprises from 40 to 100 phr of natural rubber and from 0 to 60 phr of at least one polybutadiene.

[0173] The tire according to the invention is intended to equip motor vehicles of the passenger car, SUV ("Sport Utility Vehicles"), or two-wheeled vehicles (in particular motorcycles), or airplanes, or even industrial vehicles chosen from vans, "Heavy Goods Vehicles", - that is to say metro, buses, road transport vehicles (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering vehicles -, and others. Preferably, the tire according to the invention is particularly suitable for equipping passenger car, van and SUV type vehicles.

[0174] The following examples are given for illustrative purposes. They should in no way be considered as limiting the present invention.

[0175] EXAMPLES

[0176] Measurement methods

[0177] Traction measurements:

[0178] Tensile tests are used to determine the elastic moduli and breaking properties and are based on the NF ISO 37 standard of December 2005.

[0179] The nominal secant modulus (or apparent stress, in MPa, related to the deformation, which is unitless) is measured at 23°C in second elongation (i.e. after an accommodation cycle at the elongation rate planned for the measurement itself) at 10% elongation (noted MA10).

[0180] The tearability indices are measured at 23°C. In particular, the force required to achieve rupture (in N / mm) is determined and the strain at rupture (in %) is measured on a test piece measuring 10 x 85 x 2.5 mm, notched in the center of its length by 3 notches to a depth of 5 mm, to cause the specimen to rupture. This allows the energy required to cause the specimen to rupture to be determined, which is the product of the rupture force and the rupture strain.

[0181] The results are given in base 100, that is to say that the values ​​are expressed in relation to a control, the measured value of which is considered as the reference at 100.

[0182] Thus, a lower value of the breaking energy represents a decrease in tear resistance performance (i.e., a decrease in breaking energy), while a higher value represents better performance.

[0183] Dynamic properties:

[0184] The dynamic properties G* and tan(5)max are measured on a viscoanalyzer (Metravib V A4000) according to ASTM D 5992-96. The response of a sample of vulcanized composition (cylindrical specimen 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, under variable temperature conditions, notably at 23°C, according to ASTM D 1349-99, is recorded. A peak-to-peak strain amplitude sweep is carried out from 0.1% to 50% (forward cycle) then from 50% to 1% (return cycle). The results used are the complex dynamic shear modulus (G*) and the loss factor (tan 5). The maximum observed value of tan 5 (tan(ô)max) and the difference in complex modulus (AG*) between the values ​​at 0.1% and 50% strain (Payne effect) are shown for the return cycle.The lower the value of tan(5) at 23°C, the lower the hysteresis of the composition and therefore the lower the rolling resistance.

[0185] The results are expressed in terms of performance base 100, i.e. the value 100 is arbitrarily assigned to the control, to then compare the tan(5) at 23°C (i.e. the hysteresis - and therefore the rolling resistance) of the different solutions tested. The value in base 100 is calculated according to the operation: (tan(5) value at 23°C of the control / tan(5) value at 23°C of the sample)*100. Thus, a lower value represents a decrease in hysteresis performance (i.e. an increase in hysteresis), while a higher value represents a better hysteresis performance (i.e. lower hysteresis).

[0186] Preparation of the compositions

[0187] The following tests are carried out as follows: the diene elastomer, the reinforcing filler and the various other ingredients, with the exception of the vulcanization system, are successively introduced into an internal mixer (final filling rate: approximately 70% by volume), whose initial tank temperature is approximately 70°C. Thermomechanical work (non-productive phase) is then carried out in one step, lasting a total of approximately 3 to 4 minutes, until a maximum "drop" temperature of 165°C is reached.

[0188] The mixture thus obtained is recovered, cooled and then sulfur and an accelerator (sulfenamide) are incorporated, on a mixer (homo-finisher) at 30°C, mixing everything (productive phase) for an appropriate time (for example between 5 and 12 min). The compositions thus obtained are then calendered in the form of plates (thickness of 2 to 3 mm) or thin sheets of rubber and then subjected to a cooking step at 150°C for 25 min before measuring their physical or mechanical properties.

[0189] Tests

[0190] Tests were carried out with different rubber compositions presented in Tables 1 and 2, based on natural rubber or a blend of natural rubber and polybutadiene.

[0191] Composition T1 corresponds to a conventional composition used for the constitution of the bead. Compositions Ex 1 to Ex 6 correspond to compositions useful in the context of the present invention, with variable levels of carbon black and pyrolysis blacks, as well as with increasing levels of powder.

[0192] Compositions Ex 7 to Ex 10 correspond to compositions useful in the context of the present invention, with varying levels of carbon black and pyrolysis black, with or without the presence of powder.

[0193] Compositions Ex 1 to Ex 10 are compositions advantageously useful with the tire in accordance with the first embodiment described above.

[0194] Finally, compositions Ex 11 and 12 correspond to compositions useful in the context of the present invention, containing a blend of carbon blacks and pyrolysis blacks, as well as powders with variations in the levels of natural rubber and polybutadiene. These latter compositions are therefore not analytically comparable to the control composition T1 but make it possible to demonstrate the gain in performance on other elastomeric matrices.

[0195] Compositions Ex 11 and Ex 12 are compositions advantageously useful with the tire in accordance with the second embodiment described above.

[0196] The elongation at break (AR), the breaking energy and the modulus of elasticity under tension at 10% elongation (MAw) and the dynamic properties (G* at 10% elongation and tan delta max) are then measured after curing, i.e. after vulcanization.

[0197] The properties of the compositions are presented in Tables 1 and 2.

[0198] Table 1: Formulations (contents expressed in pce) and properties of compositions T1 and Ex 1 to Ex 6.

[0199] (1) Natural rubber

[0200] (2) Polybutadiene

[0201] (3) Carbon black grade ASTM N550 - Cabott Company; BET (according to ASTM D6556-10): 39 m2 / g, COAN: 85 ml / 100g

[0202] (4) Pyrolysis carbon black P550 - Scandinavian Enviro Systems Company (ash (%): 18.5; sulfur (%): 3; zinc (%): 4.5; STSA specific surface area: 56 m 2 / g (ASTM D6556-2021); void volume at 50MPa: 44ml / 100g (ASTM D7854-21))

[0203] (5) “PolyDyne” rubber crumb - Lehigh Company; Particle size (according to ASTM D5644-01): 60 mesh<12%

[0204] (7) Gem rosin

[0205] (8) Combination of two antioxidants TMQ ((N-(1,3-dimethylbutyl)-N-phenyl-para-phenylenediamine (“Santoflex 6-PPD” from Flexsys) and 2,2,4-trimethyl-1,2-dihydroquinolone (“TMQ” from Lanxess)

[0206] (9) “Varazon 4959” wax - Sasol Company

[0207] (10) Sulfur

[0208] (11) Stearic acid “Pristerene 4931” - Uniqema

[0209] (12) N-tert-butyl-2-benzothiazyl sulfenamide ("Santocure TBBS") - Flexsys (13) Industrial grade zinc oxide - Umicore Company Table 2: Formulations (contents expressed in pce) and properties of compositions T1 and Ex 7 to Ex 12.

[0210] (1) Natural rubber

[0211] (2) Polybutadiene

[0212] (3) Carbon black grade ASTM N550 - Cabott Company; BET (according to ASTM D6556-10): 39 m2 / g, COAN: 85 ml / 100g

[0213] (4) Pyrolysis carbon black P550 - Scandinavian Enviro Systems Company (ash (%): 18.5; sulfur (%): 3; zinc (%): 4.5; STSA specific surface area: 56 m 2 / g (ASTM D6556-2021); void volume at 50MPa: 44ml / 100g (ASTM D7854-21))

[0214] (5) “PolyDyne” rubber crumb - Lehigh Company; Particle size (according to ASTM D5644-01): 60 mesh<12%

[0215] (6) TDAE “VivaTec 500” oil - H&R Company

[0216] (7) Gem rosin

[0217] (8) Combination of two antioxidants TMQ ((N-(1,3-dimethylbutyl)-N-phenyl-para-phenylenediamine (“Santoflex 6-PPD” from Flexsys) and 2,2,4-trimethyl-1,2-dihydroquinolone (“TMQ” from Lanxess)

[0218] (9) “Varazon 4959” wax - Sasol Company

[0219] (10) Sulfur

[0220] (11) Stearic acid “Pristerene 4931” - Uniqema

[0221] (12) N-ter-butyl-2-benzothiazyl sulfenamide ("Santocure TBBS") - Flexsys

[0222] (13) Industrial grade zinc oxide - Umicore Company

[0223] It can be observed that the compositions useful in the context of the invention (Ex 1 to 10) have the same rigidity / hysteresis compromise, or even a better rigidity / hysteresis compromise in the case of Ex 1 to 6, than the control composition (T1), while having an improved tear rupture energy reflecting better cohesion of the material and resistance to attack.

Claims

CLAIMS 1. Tire comprising two beads, at least one of the beads comprising a rubber composition based on: - at least one elastomer; - 60 to 100 pce of reinforcing fillers, including 15 to 70 pce of pyrolysis carbon black and 15 to 60 pce of carbon black with a total content of carbon black and pyrolysis carbon black ranging from 60 to 90 pce; and - a crosslinking system.

2. Tire according to the preceding claim, in which the or each elastomer is a diene elastomer chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers.

3. A tire according to any one of the preceding claims, wherein the rubber composition comprises from 25 to 100 phr of natural rubber and from 0 to 75 phr of at least one polybutadiene.

4. A tire according to any one of the preceding claims, in which the composition comprises from 60 to 80 phr of reinforcing fillers, the reinforcing fillers consisting of a mixture of carbon black and pyrolysis carbon black.

5. Tire according to the preceding claim, in which the mixture of carbon black and pyrolysis carbon black comprises from 20 to 40 pce of carbon black and from 30 to 60 pce of pyrolysis carbon black.

6. A tire according to any one of the preceding claims, wherein the pyrolysis carbon black has an ash content ranging from 5 to 30% by weight, preferably from 8 to 25% by weight, relative to the total weight of the pyrolysis carbon black.

7. Tire according to any one of the preceding claims, in which the pyrolysis carbon black has a sulfur content greater than 2% by weight, preferably ranging from 2.5 to 5% by weight, relative to the total weight of the pyrolysis carbon black.

8. Tire according to any one of the preceding claims, in which the composition further comprises rubber crumb, preferably at a content greater than 0 pce and less than or equal to 20 pce.

9. A tire according to any one of the preceding claims, wherein the crosslinking system is a vulcanization system based on molecular sulfur and / or a sulfur donor agent, preferably the vulcanization system comprises between 0.5 and 10 pce of sulfur, preferably between 1 and 5 pce.

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

11. A tire according to any one of claims 1 to 10, comprising a carcass reinforcement comprising at least one carcass layer anchored in each bead forming a winding around a circumferential reinforcing element of each bead such that an axially inner portion of the carcass layer anchored in each bead is arranged axially inside an axially outer portion of the carcass layer anchored in each bead.

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

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

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

15. A tire according to any one of the preceding claims, wherein the or each bead comprises a seat layer 46 of the tire intended to be in contact with a mounting support of the tire when the tire is mounted on the mounting support, the seat layer 46 comprising the rubber composition, preferably consisting of the rubber composition.

Images