FR3140374A1 - PNEUMATIC - Google Patents

Abstract

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

Description

PNEUMATIC FIELD OF INVENTION

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

TECHNOLOGICAL BACKGROUND

• deux bourrelets destinés à entrer en contact avec un support de montage ;
• deux flancs prolongeant les bourrelets radialement vers l’extérieur et s’unissant dans un sommet comprenant une bande de roulement et une armature de sommet ;
• au moins une armature de carcasse s’étendant radialement dans chaque flanc et axialement dans le sommet, radialement intérieurement à l’armature de sommet.

Tires for passenger vehicles usually include:

• two beads intended to come into contact with a mounting support;
• two sides extending the beads radially outwards and uniting in a summit comprising a tread and a crown reinforcement;
• at least one carcass reinforcement extending radially in each sidewall and axially in the crown, radially internally to the crown reinforcement.

Each bead includes rubber compositions subjected to high stresses. They must therefore present both a sufficient level of rigidity with good performance in terms of rolling resistance and be sufficiently cohesive in order to resist external physical attacks such as for example during assembly/disassembly of tires.

In a constant concern to improve tires and reduce their environmental footprint, manufacturers aim to develop new rubber compositions meeting, among others, 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 in rigidity/tear resistance without compromising hysteresis and while incorporating a significant portion of recycled material.

BRIEF DESCRIPTION OF THE INVENTION

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

- at least one elastomer;

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

- a crosslinking system.

Other aspects of the invention are as described below and in the claims.

DEFINITIONS

By the expression "composition based on", is meant 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 less partially, during the different phases of manufacturing the composition; the composition can thus be in the totally or partially crosslinked state or in the non-crosslinked state.

By the expression "part by weight per hundred parts by weight of elastomer" (or phr), it is meant for the purposes of the present invention, the part, by mass per hundred parts by mass of elastomer or rubber, the two terms being synonymous.

Herein, unless expressly stated otherwise, all percentages (%) shown are percentages (%) by mass.

On the other hand, any interval of values designated by the expression "between a and b" represents the range of values going from more than a to less than b (that is to say limits a and b excluded) while any interval of values designated by the expression "from a to b" means the range of values going from a to b (that is to say including the strict limits a and b). In the present, when we describe an interval of values by the expression "from a to b", we also and preferentially describe the interval represented by the expression "between a and b".

The expression “radial” refers to a radius of the tire. It is in this sense that we say of a point P1 that it is “radially interior” to a point P2 (or “radially inside” the point P2) if it is closer to the axis rotation of the tire than point P2. Conversely, a point P3 is said to be “radially external to” a point P4 (or “radially external” to point P4) if it is further from the axis of rotation of the tire than point P4. We will say that we advance “radially inwards (or outwards)” when we advance in the direction of the smaller (or larger) rays. When talking about radial distances, this meaning of the term also applies.

By “radial section” or “radial section” we mean here a cut or a section along a plane which contains the axis of rotation of the tire.

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

A “circumferential” direction is the direction which, in each meridian cutting plane, is perpendicular to both a radius of the tire and the axial direction.

The compounds comprising carbon mentioned in the description may be of fossil or biosourced origin. In the latter case, they can be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass. This concerns in particular polymers, plasticizers, fillers, etc.

DETAILED DESCRIPTION OF THE INVENTION

The inventors have developed rubber compositions meeting the expressed needs.

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

- at least one elastomer;

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

- a crosslinking system.

The rubber composition may further comprise rubber crumbs and/or usual additives and processing agents.

The different constituents of the rubber composition may be as described below.

Elastomer

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

The or each elastomer can be chosen from the group consisting of diene elastomers and mixtures thereof.

By “diene” elastomer, whether natural or synthetic, must be understood in a known manner an elastomer constituted at least in part (i.e., a homopolymer or a copolymer) of diene monomer units (monomers carrying two carbon-double bonds). carbon, conjugated or not).

These diene elastomers can be classified into two categories: “essentially unsaturated” or “essentially saturated”. The term “essentially unsaturated” is generally understood to mean a diene elastomer derived at least in part from conjugated diene monomers, having a level of units or units of diene origin (conjugated dienes) which is greater than 15% (mole %); this is why diene elastomers such as butyl rubbers or copolymers of dienes and alpha-olefins of the EPDM type do not fall within the previous definition and can be described in particular as "essentially saturated" diene elastomers (rate of motifs of weak or very weak diene origin, always less than 15%).

The term diene elastomer capable of being used is particularly understood to mean:

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

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

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

As conjugated dienes, conjugated dienes having 4 to 12 carbon atoms are suitable, in particular 1,3-dienes, such as in particular 1,3-butadiene and isoprene.

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

Suitable vinyl aromatic compounds include, for example, styrene, ortho-, meta-, para-methylstyrene, the commercial "vinyl-toluene" mixture, and para-tertiobutylstyrene.

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

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

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

(b’) - any copolymer obtained by copolymerization of one or more dienes conjugated together or with one or more vinylaromatic compounds having 8 to 20 carbon atoms;

(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 unconjugated 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).

The diene elastomer can be modified, that is to say either coupled and/or star-shaped, or functionalized, or coupled and/or star-shaped and simultaneously functionalized.

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.

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 amine , secondary or tertiary, cyclic or not, a thiol, an epoxide.

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

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, of preferably from 35 to 75 phr of natural rubber and from 25 to 65 phr of at least one polybutadiene.

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).

Reinforcing filler

The composition useful in the context of the present invention comprises from 60 to 100 phr of reinforcing fillers.

The term “reinforcing filler” designates any type of filler known for its capacity to reinforce a rubber composition usable in particular for the manufacture of tires, for example organic fillers such as carbon black or pyrolysis carbon black, or inorganic fillers such as silica or alumina. It is understood that the rubber crumbs are not reinforcing fillers in the sense of the present invention, and that the possible reinforcing fillers which they contain are not taken into account in the calculation of the total content of reinforcing fillers in the composition.

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 pce. The composition can therefore also 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 pce. Below 60 pce of load, the required level of rigidity is not achieved and above 100 pce of load, industrial implementation is too difficult and the level of hysteresis is too high.

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

The reinforcing fillers can be as described below.

Pyrolysis Carbon Black

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

By “pyrolysis carbon black” is meant for the purposes of the present invention a carbon black resulting from a pyrolysis process of a material comprising at least one carbonaceous polymer and a carbon black, hereinafter the material to be pyrolyze for example in the context of recycling such a material. The physical state in which the material to be pyrolyzed is in is irrelevant, 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 manufacturing/production (such as by-products or scraps); these manufactured articles may be selected from the group consisting of pneumatic tires, non-pneumatic tires, industrial conveyor belts, transmission belts, rubber seals, rubber hoses, shoe soles and windshield wipers. Even more preferably, 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.

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

The pyrolysis carbon blacks usable in the context of the present invention differ from known carbon blacks such as industrial carbon blacks, in particular so-called “furnace” carbon blacks, in particular by a higher ash content.

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

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. .

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 carbon black. pyrolysis.

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

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

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 P0. 5 g of sample of pyrolysis carbon black are introduced into the capsule, which is weighed precisely to the nearest 0.1 mg; this mass is denoted P1. The capsule and its contents are pre-calcined using a Bunsen burner until smoke appears 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 hour. After 1 h, the capsule was removed from the oven and immediately introduced into a desiccator at room temperature. When the capsule and the ashes have returned to room temperature, the capsule is weighed again to obtain the mass P2. Finally, it is possible to obtain the ash rate (% ash) using the formula below:

The zinc content in the pyrolysis carbon black is determined after calcination of the sample, then recovery of the ashes in an acidic medium and determination by ICP-AES (inductively coupled plasma atomic emission spectroscopy). The ashes are obtained by carrying out the protocol above. Approximately exactly 100 mg of ash is taken (test portion) which is introduced into a PFA (perfluoroalkoxy) tube for 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. The tube is closed with its cap and heated to 130°C for 2 hours. After cooling, the contents are then transferred using ultrapure water into a 100 mL PTFE (polytetrafluoroethylene) volumetric flask already containing 2 g of boric acid (to neutralize the hydrofluoric acid). Complete with ultrapure water up to the mark. The solution obtained is diluted by 100, by taking 1 mL into a 100 mL PFTE flask, previously containing 8 mL of hydrochloric acid concentrated at 37%, 3 mL of nitric acid concentrated at 65%, 0.5 mL of 40% hydrofluoric acid and 2 g of boric acid. This diluted solution is then filtered through a 0.45 µm GHP syringe filter before being analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Prior to the analysis of the diluted solution, at least 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 dilution of a certified commercial solution to a zinc concentration of 1 g/L.

These volumetric flasks previously 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 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 linked to the concentration using the calibration line obtained previously. We thus obtain the [c]ash concentration in % by mass directly by the software, because the test portion and the volume have been previously recorded. The zinc concentration in the pyrolysis black [c]black in % by weight is obtained by the following equation:

The determination of the sulfur content in the pyrolysis carbon blacks is carried out by a LECO oven. 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 level on the sample, the nacelles are cleaned and the furnace is calibrated. The LECO oven pods are cleaned beforehand: this involves analyzing the empty pod, under the same conditions as the samples. The calibration curve is prepared using a commercial standard called “BBOT” whose purity is greater than 99.99% and whose content of carbon (C), hydrogen (H), nitrogen (N ), oxygen (O) and sulfur (S) is guaranteed. This content is as follows C%: 72.52; H% 6.09; N% 6.51; O% 7.43 and S% 7.44. We weigh approximately exactly 10 ± 3, 20 ± 3 and 40 ± 3 mg of BBOT in a basket. The standard/nacelle assembly is introduced into the combustion furnace, regulated at 1350°C under pure oxygen. The combination of oven temperature and analysis flow rate causes the sample to burn and the sulfur and/or carbon to be released in the form of SO ₂ (g). After a time of 20 s, oxygen begins to circulate through the “lance” to accelerate the combustion of difficult-to-burn materials. Sulfur and/or carbon, in the form of SO ₂ (g), are carried by a flow of oxygen through the infrared detection cells. The instrument software draws a line connecting the introduced standard mass and the observed response (area) on the detector. We thus obtain a calibration line. After carefully cleaning the sampling equipment, approximately exactly 80 ± 5 mg of pyrolysis carbon black are weighed out and introduced into a LECO oven basket. The area of the observed SO ₂ peak is linked to the concentration using the calibration line. The instrument software then calculates, using the mass of the sample introduced into the nacelle, the % by mass of sulfur in the sample.

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

Carbon black

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

All carbon blacks are suitable as carbon blacks, in particular blacks conventionally used in tires or their treads, in particular industrial carbon blacks, more specifically so-called “furnace” carbon blacks.

Among the carbon blacks, we will more particularly mention the reinforcing carbon blacks of the 100, 200, 300 series, or the blacks of the 500, 600 or 700 series (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 isolated state, as commercially available, or in any other form, for example as a support for some of the rubber additives used. The 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

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

By “reinforcing inorganic filler”, must be understood here any inorganic or mineral filler, whatever its color and its 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. In known manner, certain reinforcing inorganic fillers can be characterized in particular by the presence of hydroxyl groups (-OH) on their surface.

Suitable reinforcing inorganic fillers are mineral fillers of the siliceous type, preferably silica (SiO ₂ ) or of the aluminous type, in particular alumina (Al ₂ O ₃ ). The silica used can be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET specific surface as well as a CTAB specific surface both less than 450 m ² /g, preferably included in a range ranging from 30 to 400 m ² /g, in particular from 60 to 300 m ² /g.

Any type of precipitated silica can 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. We can cite, for example, the silicas described in applications WO 03/016215-A1 and WO 03/016387-A1. Among the commercial HDS silicas, it is possible in particular to use 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 Solvay Company. As non-HDS silica, the following commercial silicas can be used: “Ultrasil ® VN2GR” silicas, “Ultrasil ® VN3GR” silicas from the company Evonik, “Zeosil® 175GR” silica from the company Solvay, “Hi -Sil EZ120G(-D)”, “Hi-Sil EZ160G(-D)”, “Hi-Sil EZ200G(-D)”, “Hi-Sil 243LD”, “Hi-Sil 210”, “Hi-Sil HDP 320G” from PPG.

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/in: 0.05 to 0.17). The CTAB specific surface area of the silica is determined according to the French standard NF T 45-007 of November 1987 (method B).

As other examples of inorganic fillers capable of being used in the compositions, mineral fillers of the aluminous type may also be cited, in particular alumina (Al ₂ O ₃ ), aluminum oxides, hydroxides of aluminum, 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. We can cite in particular the aluminas “Baikalox A125” or “CR125” (Baïkowski company), “APA-100RDX” (Condéa), “Aluminoxid C” (Evonik) or “AKP-G015” (Sumitomo Chemicals).

The physical state in which the reinforcing inorganic filler is presented is irrelevant, 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.

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, since this reinforcing filler of another nature would be covered with an inorganic layer. such as silica, or would have functional sites on its surface, in particular hydroxyl sites, requiring the use of a coupling agent to establish the connection between this reinforcing filler and the diene elastomer. By way of example, mention may be made of carbon blacks partially or entirely covered with silica, or carbon blacks modified by silica, such as, without limitation, the “Ecoblack®” type fillers of the series CRX2000” or the “CRX4000” series from Cabot Corporation.

Those skilled in the art will know how to adapt the total rate of reinforcing load according to the use concerned, in particular according to the type of tires concerned, for example tires for motorcycles, for passenger vehicles or even for utility vehicles such as vans or heavy goods vehicles.

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 chemical and/or physical nature, between the filler. inorganic (surface of its particles) and 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 charge and a second functional group comprising a sulfur atom, said second functional group being capable of interacting with the diene elastomer.

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

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

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

The composition may also contain, in addition to the coupling agents, coupling activators, inorganic charge recovery agents or more generally processing aids capable in a known manner, thanks to an improvement in dispersion. of the filler in the rubber matrix and a lowering of the viscosity of the compositions, to improve their ability to be used 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, ω-dihydroxy-polyorganosiloxanes (in particular α, ω-dihydroxy-polydimethylsiloxanes), fatty acids such as for example stearic acid.

Other organic loads

As an example of organic fillers other than carbon blacks and pyrolysis carbon blacks, mention may be made of 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.

Rubber powder

The composition useful in the context of the invention may comprise rubber crumbs (abbreviated as “powder” in the following). Thus, the composition typically comprises 0 to 20 phr of rubber crumb.

In certain embodiments, the composition does not include rubber crumb.

In certain embodiments, the composition comprises rubber crumbs whose content in the composition is greater than 0 phr and less than or equal to 20 phr, for example from 1 to 20 phr or from 10 to 20 phr.

The powder is in the form of granules, possibly put in the form of a rubber plate. Most often, rubber crumbs come from grinding or micronization of cooked rubber compositions already used for a first application, for example in tires, they are a material recycling product. The powder is therefore preferably made up of a composition based on at least one elastomer and a filler. Preferably the powder is in the form of microparticles.

By “microparticles” we mean 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 powders are preferably made up of a composition based on an elastomer and a filler. They can also include all the ingredients usually used in rubber compositions such as plasticizers, antioxidants, vulcanization additives, etc.

Thus, the powder 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 powder, percentage determined according to standard ASTM E1 131. It is preferentially chosen in 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%.

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

By filler, we mean here any type of filler, whether it is reinforcing (typically with nanometric particles, and preferably of weight average size 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 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 micrometric particles can be determined by mechanical sieving.

As examples of fillers known as reinforcing by those skilled in the art, mention will be made in particular of carbon black or a reinforcing inorganic filler such as silica or alumina in the presence of a coupling agent, or their mixtures.
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.

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.

Very preferably, the carbon black is present in the powder at a level ranging from 20 to 40% by weight, more preferably from 25 to 35% by weight.

As carbon blacks, all carbon blacks are suitable, in particular blacks of the type HAF, ISAF, SAF, FF, FEF, GPF and SRF conventionally used in rubber compositions for tires (so-called pneumatic grade blacks).
The crumb can contain all the other usual additives which enter into 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, vulcanization agents. These additives can also be found in the powder 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 powder is obtained.

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 weight, more preferably included in a range ranging from 5 to 25% by weight.

Also, it is preferable that the powder has a chloroform extract of between 5 and 85% by weight, more preferably included in a range ranging from 5 to 50% by weight.

The powders can be simple crushed rubber/micronisates, without further treatment. It is also known that these powders can undergo treatment in order to modify them. This treatment may consist of a chemical modification of functionalization or devulcanization. It can also be a thermomechanical, thermochemical, biological treatment, etc.

Grinding can be carried out by different technologies, in particular cryogenic impact micronization technologies which make it possible to obtain small particles on rubber materials. Commercial equipment such as the CUM150 crushers from Netzsch or CW250 from Alpine can be used.
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.

According to this first embodiment, it is preferred that the powder has an acetone extract of between 5 and 20% by weight, more preferably included in a range ranging from 10 to 18% by weight. Also, it is preferred that the powder has a chloroform extract of between 15 and 85% by weight, more preferably included in a range ranging from 15 to 50% by weight. Preferably, the chloroform extract of the rubber crumb 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.

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.

Also preferably according to this first embodiment, the powder has a Mooney viscosity (conventionally expressed in Mooney units, UM) of between 40 and 90, preferably between 45 and 75 and more preferably between 50 and 70.

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

According to this second embodiment, it is preferred that the powder has an acetone extract of between 3 and 15% by weight, more preferably included in a range ranging from 3 to 10% by weight. Also, it is preferred that the powder has a chloroform extract of between 3 and 20% by weight, more preferably included in a range ranging from 5 to 15% by weight. Preferably, the chloroform extract of the rubber crumb has a mass-average molecular mass (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.

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

Reticulation system

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

The crosslinking system can be any type of system known to those skilled in the art in the field of rubber compositions for tires. It may in particular be based on sulfur, and/or peroxide and/or bismaleimides.

Preferably, the crosslinking system is based on sulfur, we then speak of a vulcanization system. The sulfur can be provided in any form, in particular in the form of molecular sulfur, or of a sulfur-donating agent. At least one vulcanization accelerator is also preferably present, and, optionally, also preferentially, various known vulcanization activators can be used such as zinc oxide, stearic acid or equivalent compound such as stearic acid salts and salts. transition metals, guanidic derivatives (in particular diphenylguanidine), or even known vulcanization retarders.

Sulfur is used at a preferential rate of between 0.5 and 10 pce, in particular between 1 and 5 pce. The vulcanization accelerator is used at a preferential rate of between 0.5 and 10 phr, more preferably between 0.5 and 5.0 phr.

Any compound capable of acting as an accelerator for the vulcanization of diene elastomers in the presence of sulfur can be used as an accelerator, in particular accelerators of the thiazole type as well as their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. As examples of such accelerators, the following compounds may be cited in particular: 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl- 2-benzothiazyl sulfenamide ("DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-ter-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD") , zinc dibenzyldithiocarbamate (“ZBEC”) and mixtures of these compounds.

Common additives and processing agents

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 having or without a tackifying character), non-reinforcing fillers, pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, anti-oxidants, anti-fatigue agents, reinforcing resins (as described for example in application WO 02/10269).

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.

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 (Medium Extracted Solvates) oils, TDAE (Treated Distillate Aromatic Extracts) oils, 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.

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 polymeric matrices. They are by nature at least partially miscible (i.e., compatible) at the levels 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, particularly in pneumatic rubber (5.5. “Rubber Tires and Mechanical Goods”). In known manner, these hydrocarbon resins can also be described as thermoplastic resins in the sense that they soften by heating and can thus be molded.

The softening point of hydrocarbon resins is measured according to the ISO 4625 standard (“Ring and Ball” method). 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): solvent tetrahydrofuran; temperature 35°C; concentration 1 g/l; flow rate 1 ml/min; solution filtered on a filter with a porosity of 0.45 µm 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").

The hydrocarbon resins can be aliphatic, or aromatic or even of the aliphatic/aromatic type, that is to say based on aliphatic and/or aromatic monomers. They can be natural or synthetic, petroleum-based or not (if so, also known as petroleum resins).

As aromatic monomers suitable for example are styrene, alpha-methylstyrene, indene, ortho-, meta-, para-methylstyrene, vinyl-toluene, para-tertiobutylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, any vinylaromatic monomer from a C9 cut (or more generally from a C8 to C10 cut). 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 mole fraction, in the copolymer considered.

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.

The term “terpene” here groups together in a known manner the alpha-pinene, beta-pinene and limonene monomers; the limonene monomer presents itself in a known manner in the form of three possible isomers: L-limonene (levorotatory enantiomer), D-limonene (dextrorotatory enantiomer), or dipentene, racemic of the dextrorotatory and levorotatory enantiomers. Among the hydrocarbon plasticizing resins above, we will notably cite resins of homo- or copolymers of alphapinene, betapinene, dipentene or polylimonene.

In known manner, high Tg hydrocarbon resins are hydrocarbon, thermoplastic resins, whose Tg is greater than 20°C.

• une Tg supérieure à 30°C ;
• une masse moléculaire moyenne en nombre (Mn) comprise entre 300 et 2000 g/mol, plus préférentiellement entre 400 et 1500 g/mol ;
• un indice de polymolécularité (Ip) inférieur à 3, plus préférentiellement inférieur à 2 (rappel : Ip = Mw/Mn avec Mw masse moléculaire moyenne en poids).

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 mass (Mn) of between 300 and 2000 g/mol, more preferably between 400 and 1500 g/mol;
• a polymolecularity index (Ip) less than 3, more preferably less than 2 (reminder: Ip = Mw/Mn with Mw weight average molecular mass).

More preferably, this high Tg hydrocarbon plasticizing resin has all of the above preferential characteristics.

• résines polylimonène : par la société DRT sous la dénomination "Dercolyte L120" (Mn=625 g/mol ; Mw=1010 g/mol ; Ip=1,6 ; Tg=72°C) ou par la société ARIZONA sous la dénomination "Sylvagum TR7125C" (Mn=630 g/mol ; Mw=950 g/mol ; Ip=1,5 ; Tg=70°C) ;
• résines de copolymère coupe C5/ vinylaromatique, notamment coupe C5/ styrène ou coupe C5/ coupe C9 : par Neville Chemical Company sous les dénominations "Super Nevtac 78", "Super Nevtac 85" ou "Super Nevtac 99", par Goodyear Chemicals sous dénomination "Wingtack Extra", par Kolon sous dénominations "Hikorez T1095" et "Hikorez T1100", par Exxon sous dénominations "Escorez 2101" et "Escorez 1273" ;
• résines de copolymère limonène/ styrène : par DRT sous dénomination "Dercolyte TS 105" de la société DRT, par ARIZONA Chemical Company sous dénominations "ZT115LT" et "ZT5100".

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

• polylimonene resins: by the company DRT under the name "Dercolyte L120" (Mn=625 g/mol; Mw=1010 g/mol; Ip=1.6; Tg=72°C) or by the company ARIZONA under the name " Sylvagum TR7125C" (Mn=630 g/mol; Mw=950 g/mol; Ip=1.5; Tg=70°C);
• C5 cut/vinylaromatic copolymer resins, in particular C5 cut/styrene or C5 cut/C9 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 the company DRT, by ARIZONA Chemical Company under the names “ZT115LT” and “ZT5100”.

As examples of other preferred resins, we can also cite phenol-modified alpha-methyl-styrene resins. To characterize these phenol-modified resins, it is recalled that an index called the "hydroxyl index" is used in a known manner (measured according to ISO 4326 standard and expressed in mg KOH/g). Alpha-methyl-styrene resins, in particular those modified by phenol, are well known to those skilled in the art and available commercially, for example sold by the company 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).

We can also cite resins from the alkyl-phenol family such as octylphenyl formalin (OPF) available for example under the name “SP 1068” from the company SI Group as well as gem rosin resins such as supplied for example by the company Costa Irmaos.

Manufacturing of compositions

• une première phase de travail ou malaxage thermomécanique (phase dite « non-productive »), qui peut être conduite en une seule étape thermomécanique au cours de laquelle on introduit, dans un mélangeur approprié tel qu'un mélangeur interne usuel (par exemple de type 'Banbury'), tous les constituants nécessaires, notamment la matrice élastomérique, les charges, les éventuels autres additifs divers, à l'exception du système de réticulation. L’incorporation de la charge à l’élastomère peut être réalisée en une ou plusieurs fois en malaxant thermomécaniquement. Dans le cas où la charge est déjà incorporée en totalité ou en partie à l’élastomère sous la forme d’un mélange-maître (« masterbatch » en anglais) comme cela est décrit par exemple dans les demandes WO 97/36724 ou WO 99/16600, c’est le mélange-maître qui est directement malaxé et le cas échéant on incorpore les autres élastomères ou charges présents dans la composition qui ne sont pas sous la forme de mélange-maître, ainsi que les éventuels autres additifs divers autres que le système de réticulation.

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

• a first working phase or thermomechanical mixing (so-called “non-productive” phase), which can be carried out in a single thermomechanical step during which we introduce, into a suitable mixer such as a usual internal mixer (for example of the type 'Banbury'), all the necessary constituents, in particular the elastomeric matrix, the fillers, any other various additives, with the exception of the crosslinking system. The incorporation of the filler into the elastomer can be carried out in one or several times 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 kneaded and if necessary the other elastomers or fillers present in the composition which are not in the form of masterbatch are incorporated, as well as any other various additives other than the reticulation system.

• une seconde phase de travail mécanique (phase dite « productive »), qui est réalisée dans un mélangeur externe tel qu'un mélangeur à cylindres, après refroidissement du mélange obtenu au cours de la première phase non-productive jusqu'à une plus basse température, typiquement inférieure à 110°C, par exemple entre 40°C et 100°C. On incorpore alors le système de réticulation, et le tout est alors mélangé pendant quelques minutes, par exemple entre 1 et 30 min.

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

• a second phase of mechanical work (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.

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

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

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

The examples which follow are given for illustrative purposes, but should in no way be considered as limiting the present invention.

TIRES

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.

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

More precisely, 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 intended in particular to be in contact with a hook on 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 delimited radially on the outside by the point of the external surface of the bead of the radially outermost tire to be in contact with a rim measurement of the tire according to the manual of the ETRTO standard (in English, “European Tire and Rim Technical Organization”), 2021 when the tire is inflated to its nominal pressure on this measuring rim.

In certain embodiments, the tire comprises a carcass reinforcement comprising at least one layer of carcass anchored in each bead forming a winding around a circumferential reinforcing element of each bead so that an axially interior portion of the layer of carcass anchored in each bead is arranged axially inside an axially exterior portion of the carcass layer anchored in each bead.

In these embodiments, the bead is relatively stressed by the carcass reinforcement due to the winding it forms there. Thus, in order to ensure sufficient resistance of the rubber composition in these particularly demanding embodiments, the rubber composition typically comprises several elastomers, in particular it can comprise from 25 to 60 phr of natural rubber and from 40 to 75 phr of at least one polybutadiene.

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

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-demand embodiments advantageously comprises a higher proportion of natural rubber. The composition can 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.

In particularly advantageous embodiments, the or each bead comprises a seating layer 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 seating layer comprising the rubber composition, preferably consisting of the rubber composition described above.

Conventionally, the mounting support is a rim.

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

• deux bourrelets destinés à entrer en contact avec un support de montage;
• deux flancs prolongeant les bourrelets radialement vers l’extérieur et s’unissant dans un sommet comprenant une bande de roulement et une armature de sommet ;
• au moins une armature de carcasse s’étendant radialement dans chaque flanc et axialement dans le sommet, radialement intérieurement à l’armature de sommet.

As indicated previously, tires, particularly for passenger vehicles, usually include:

• two beads intended to contact a mounting bracket;
• two sides extending the beads radially outwards and uniting in a summit comprising a tread and a crown reinforcement;
• at least one carcass reinforcement extending radially in each sidewall and axially in the crown, radially internally to the crown reinforcement.

• la est une vue, dans un plan de coupe méridien parallèle à l’axe de rotation du pneumatique, d’un pneumatique selon un premier mode de réalisation, et
• la est une vue analogue à celle de la d’un pneumatique selon un deuxième mode de réalisation.

The invention will be better understood on reading the description which follows, given solely by way of non-limiting example and made with reference to the drawings in which:

• there 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
• there is a view analogous to that of the of a tire according to a second embodiment.

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

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

We represented on the a tire, in accordance with 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 to 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 internal seal 18 to an inflation gas being intended to delimit an internal cavity with a mounting support of the tire 10 once the tire 10 mounted on the mounting support, for example a rim, this cavity being intended to be placed under pressure by the inflation gas.

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

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 one 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 internally to the crown reinforcement 16.

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 rod, so that a axially interior portion 361 of the carcass layer 36 anchored in each bead 32 is arranged axially inside an axially exterior portion 362 of the carcass layer 36 anchored in each bead 32 and so that each axial end 363 axially delimits the carcass layer 36 anchored in each bead 32 is arranged radially outside of each circumferential reinforcement element 35.

Each bead 32 comprises a first layer 42, called a padding 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 interior portion 361 and the axially exterior portion 362.

Each bead 32 also includes a second layer 44, arranged axially outside the axially exterior portion 362 and the first padding layer 42.

Each bead 32 also includes a third layer 46, called the seat layer of the tire 10. The third seat 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 seating layer 46 is arranged axially outside the circumferential reinforcing element 35 and more precisely axially between the circumferential reinforcing element 35 and the mounting support (not shown) when the tire is mounted on this support.

At least one of the first, second and third layers 42, 44, 46 comprises, preferably consists of, a rubber composition according to the invention. In the example illustrated, the third seat layer 46 is made of a rubber composition according to the invention. In particular, the rubber composition of the third seat layer 46 notably comprises 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.

We represented on the a tire according to a second embodiment of the invention. Elements similar to those illustrated on the are designated by identical references.

Unlike the tire according to the first embodiment, the tire 10 according to the second embodiment is such that, for the purposes of anchoring the carcass layer 36, the tire 10 comprises an axially interior circumferential reinforcement element 38 arranged axially inside the carcass layer 36 and an axially exterior circumferential reinforcement element 40 arranged axially outside the carcass layer 36. Here each reinforcement element 38, 40 comprises a continuous wire reinforcement element wound on 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 consists of, a rubber composition according to the invention. In the example illustrated, the third seat layer 46 is made of a rubber composition according to the invention. In particular, the rubber composition of the third seat layer 43 notably comprises 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.

The tire according to the invention is intended to equip motor vehicles of the tourism type, SUV ("Sport Utility Vehicles"), or two wheels (in particular motorcycles), or airplanes, or even industrial vehicles chosen from vans, "Weight- heavy", - 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, van and SUV type vehicles.

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

EXAMPLES Measurement methods

Tensile measurements:

Tensile tests make it possible to determine the elastic moduli and breaking properties and are based on the NF ISO 37 standard of December 2005.

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 a cycle of accommodation at the elongation rate intended for the measurement itself) at 10% elongation (noted MA10).

Tearability indices are measured at 23°C. In particular, we determine the force to be exerted to obtain rupture (in N/mm) and we measure the deformation at rupture (in %) on a specimen of dimensions 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 test specimen to break. Thus we can determine the energy to cause the rupture of the specimen which is the product of the rupture force and the rupture strain.

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

Thus, a lower value of the energy at break represents a decrease in tear resistance performance (i.e. a decrease in energy at break), while a higher value represents a better performance.

Dynamic properties:

The dynamic properties G* and tan(δ)max are measured on a viscoanalyzer (Metravib V A4000) according to standard ASTM D 5992-96. The response of a sample of vulcanized composition (cylindrical specimen with a thickness of 4 mm and a section of 400 mm2), subjected to a simple alternating sinusoidal shear stress, at a frequency of 10 Hz, under conditions of variable temperature, in particular at 23°C, according to standard ASTM D 1349-99, is recorded. A peak-to-peak strain amplitude sweep is performed 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 δ). The maximum value of tan δ observed (tan(δ)max) and the difference in complex modulus (ΔG*) between the values at 0.1% and 50% strain (Payne effect) are represented for the return cycle.

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

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

Preparation of compositions

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

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 then are subjected to a baking step at 150°C for 25 min before measuring their physical or mechanical properties. .

Trials

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.

The T1 composition corresponds to a classic 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 black, as well as with increasing levels of powder.

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.

Compositions Ex 1 to Ex 10 are compositions advantageously useful with the tire conforming to the first embodiment described above.

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 on 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 performance gain on other elastomeric matrices.

Compositions Ex 11 and Ex 12 are compositions advantageously useful with the tire conforming to the second embodiment described above.

We then measure when cooked, therefore after vulcanization, the elongation at break (AR), the breaking energy and the modulus of elasticity under tension at 10% elongation (MA ₁₀ ) and the dynamic properties (G* at 10% elongation and tan delta max).

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

T1 Ex 1 Ex 2 Ex 3 Ex 4 Ex 5 Ex 6 NR (1) 50 50 50 50 50 50 50 BR (2) 50 50 50 50 50 50 50 Carbon black (3) 65 35 35 50 35 20 35 Pyrolysis black (4) 0 35 35 18 35 53 35 Rubber powder (5) 0 6 10 15 15 15 20 Resin (7) 1 1 1 1 1 1 1 Anti-oxidants (8) 4 4 4 4 4 4 4 Anti-ozone wax (9) 1 1 1 1 1 1 1 Sulfur (10) 2.0 2.0 2.1 2.1 2.1 2.1 2.2 Stearic acid (11) 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Accelerator (12) 1.1 1.1 1.2 1.2 1.2 1.2 1.2 Zinc oxide (13) 4 4 4 4 4 4 4 MA10 23°C (MPa)
Basis 100 100 98 95 95 96 100 98 G*10% 23°C (MPa)
Basis 100 100 91 96 95 94 93 95 Tearability rupture elongation AR 23°C (%)
Basis 100 100 227 226 214 221 208 217 Tearability rupture stress FR 23°C (N/mm)
Basis 100 100 223 208 198 208 192 204 Tearability rupture energy 23°C (mJ)
Basis 100 100 396 470 424 458 401 444 Tan delta max 23°C
Basis 100 100 114 113 106 108 117 109

Table 1: Formulations (contents expressed in phr) and properties of compositions T1 and Ex 1 to Ex 6.

(1) Natural rubber

(2) Polybutadiene

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

(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))

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

(7) Gem Rosin

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

(9) “Varazon 4959” wax – Sasol Company

(10) Sulfur

(11) Stearic acid “Pristerene 4931” - Uniqema

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

(13) Industrial grade zinc oxide – Umicore Company

T1 Ex 7 Ex 8 Ex 9 Ex10 Ex11 Ex12 NR (1) 50 50 50 50 50 70 100 BR (2) 50 50 50 50 50 30 0 Carbon black (3) 65 37 21 37 21 34 36 Pyrolysis black (4) 0 38 56 38 56 33 36 Rubber powder (5) 0 0 0 15 15 15 15 Oil (6) 0 4 4 4 4 0 0 Resin (7) 1 2 2 2 2 5 5 Anti-oxidants (8) 4 4 4 4 4 4 4 Anti-ozone wax (9) 1 1 1 1 1 1 1 Sulfur (10) 2 2.2 2.2 2.4 2.4 2.7 2.7 Stearic acid (11) 1.5 1.5 1.5 1.5 1.5 3 3 Accelerator (12) 1.1 1.2 1.2 1.3 1.3 1.3 1.3 Zinc oxide (13) 4 4 4 4 4 4 4 MA10 23°C (MPa)
Basis 100 100 99 96 100 94 102 103 G*10% 23°C (MPa)
Basis 100 100 103 98 108 101 106 110 Tearability rupture elongation AR 23°C (%)
Basis 100 100 151 150 139 136 153 126 Tearability rupture stress FR 23°C (N/mm)
Basis 100 100 131 120 118 107 138 126 Tearability rupture energy 23°C (mJ)
Basis 100 100 198 180 163 146 211 159 Tan delta max 23°C
Basis 100 100 101 108 95 101 95 80

Table 2: Formulations (contents expressed in phr) and properties of compositions T1 and Ex 7 to Ex 12.

(1) Natural rubber

(2) Polybutadiene

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

(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))

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

(6) TDAE “VivaTec 500” oil – H&R Company

(7) Gem Rosin

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

(9) “Varazon 4959” wax – Sasol Company

(10) Sulfur

(11) Stearic acid “Pristerene 4931” - Uniqema

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

(13) Industrial grade zinc oxide – Umicore Company

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, as the control composition ( T1), while presenting an improved tearability breaking energy reflecting better cohesion of the material and resistance to attacks.

Claims (15)

Tire comprising two beads, at least one of the beads comprising a rubber composition based on:
- at least one elastomer;
- 60 to 100 phr of reinforcing fillers, including 15 to 70 phr of pyrolysis carbon black and 15 to 60 phr of carbon black with a total content of carbon black and pyrolysis carbon black ranging from 60 to 90 pce; And
- a crosslinking system. 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, copolymers isoprene, and mixtures of these elastomers. Tire according to any one of the preceding claims, in which the rubber composition comprises from 25 to 100 phr of natural rubber and from 0 to 75 phr of at least one polybutadiene. 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. Tire according to the preceding claim, in which the mixture of carbon black and pyrolysis carbon black comprises from 20 to 40 phr of carbon black and from 30 to 60 phr of pyrolysis carbon black. Tire according to any one of the preceding claims, in which 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 carbon black. pyrolysis carbon. 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 black of pyrolysis carbon. Tire according to any one of the preceding claims, in which the composition further comprises crumbs of rubber, preferably at a content greater than 0 phr and less than or equal to 20 phr. Tire according to any one of the preceding claims, in which 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. Tire according to any one of the preceding claims, in which 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, anti-oxidants, anti-fatigue agents and reinforcing resins. Tire according to any one of claims 1 to 10, comprising a carcass reinforcement comprising at least one layer of carcass anchored in each bead forming a winding around a circumferential reinforcing element of each bead so that an axially interior portion of the carcass layer anchored in each bead is arranged axially inside an axially exterior portion of the carcass layer anchored in each bead. Tire according to the preceding claim, in which the rubber composition comprises from 25 to 60 phr of natural rubber and from 40 to 75 phr of at least one polybutadiene. 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 comprises an axially interior circumferential reinforcing element arranged axially inside the carcass layer anchored in each bead and an axially exterior circumferential reinforcing element arranged axially outside the carcass layer anchored in each bead. Tire according to the preceding claim, in which the rubber composition comprises from 40 to 100 phr of natural rubber and from 0 to 60 phr of at least one polybutadiene. Tire according to any one of the preceding claims, in which the or each bead comprises a seating layer 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 layer seat comprising the rubber composition, preferably consisting of the rubber composition.