WO2024133256A1

WO2024133256A1 - Elastomer compositions comprising a silicon-treated carbon black

Info

Publication number: WO2024133256A1
Application number: PCT/EP2023/086637
Authority: WO
Inventors: Etienne Fleury
Original assignee: Compagnie Generale Des Etablissements Michelin
Priority date: 2022-12-21
Filing date: 2023-12-19
Publication date: 2024-06-27
Also published as: FR3144143A1

Abstract

The present disclosure relates to an elastomer composition based on: - a diene elastomer having a glass transition temperature of less than or equal to -45°C measured according to standard ASTM D3418-2008 and comprising, in the middle of the chain, at least one Si-OR function in which R is a substituted or unsubstituted alkyl group or a hydrogen atom; - a reinforcing filler comprising at least one silicon-treated carbon black; and - a crosslinking system.

Description

ELASTOMERIC COMPOSITIONS COMPRISING A PROCESSED CARBON BLACK

SILICON

FIELD OF INVENTION

The present invention relates to the field of reinforced elastomeric compositions, in particular intended for the manufacture of rubber articles, such as in particular semi-finished articles for pneumatic or non-pneumatic tires, in particular for vehicles carrying heavy loads.

TECHNOLOGICAL BACKGROUND

Ideally, the elastomeric compositions constituting the treads of pneumatic or non-pneumatic tires must comply with a large number of technical requirements, often contradictory, including high resistance to wear while offering the tire low rolling resistance.

Initially, carbon black is used in elastomeric compositions as a reinforcing filler to limit tire wear. Due to its good dispersibility in the elastomeric matrix, carbon black makes it possible to obtain good reinforcing properties and therefore good wear resistance properties.

But since fuel savings and the need to protect the environment have become a priority, it has become necessary to produce pneumatic or non-pneumatic tires with reduced rolling resistance without penalizing their wear resistance.

This was made possible in particular thanks to the use, in the treads, of new rubber compositions reinforced with inorganic fillers, in particular specific silicas of the highly dispersible type, capable of competing from the reinforcing point of view with a black of conventional pneumatic grade carbon, while offering these compositions lower hysteresis, synonymous with lower rolling resistance for pneumatic or non-pneumatic tires containing them.

To obtain optimal reinforcing properties conferred by a load in a tread and thus high wear resistance, it is known that it is generally necessary for this load to be present in the elastomeric matrix in a final form. which is both as finely divided as possible and distributed in the most homogeneous way possible. However, such conditions can only be achieved to the extent that this reinforcing filler has a very good ability, on the one hand to be incorporated into the elastomeric matrix when mixed with the elastomer and to deagglomerate, on the other hand. starts to disperse homogeneously in this elastomeric matrix. As is known, silicas have poorer dispersion and incorporation capabilities than carbon black. Indeed, for reasons of reciprocal affinities, the silica particles have a tendency, in the elastomeric matrix, to agglomerate together. These interactions have the harmful consequence of limiting the dispersion of the silica and therefore the reinforcing properties of the elastomeric composition containing it.

Thus new reinforcing fillers have been developed in an attempt to obtain the good hysterical properties conferred by silica and the good dispersion of carbon black. These new reinforcing fillers are silicon-treated carbon blacks. They are described in particular in document EP0711805. If this carbon black treated with silicon nevertheless makes it possible, in a composition comprising a non-functional elastomer, to obtain a reduction in hysteresis (therefore an improvement in rolling resistance), this is however obtained at the cost of a reduction in rigidity and reinforcement properties, therefore resulting in less resistance to wear.

There is therefore still a need to provide compositions which satisfy a good rigidity/hysteresis compromise with maintenance of other mechanical properties, these compositions being able to be particularly useful for forming all or part of the tread of a pneumatic tire or not. pneumatic.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to an elastomeric composition based on: a diene elastomer having a glass transition temperature less than or equal to -45°C measured according to standard ASTM D3418-2008 and comprising, in the middle of the chain, at least one Si function -OR in which R is an alkyl group, substituted or not, or a hydrogen atom; a reinforcing filler comprising at least one silicon-treated carbon black; and a crosslinking system.

Surprisingly, the inventors have discovered that the specific combination of at least one diene elastomer as described below and at least one reinforcing filler as described below makes it possible to obtain an elastomeric composition meeting the needs expressed, the composition being usable in particular in a tread, in particular for a pneumatic or non-pneumatic tire intended to equip vehicles in particular carrying heavy loads. The proposed solution makes it possible to obtain a good compromise between rigidity/hysteresis (wear resistance/rolling resistance) while also having improved reinforcement properties.

The present invention also relates to a rubber article comprising at least one such elastomeric composition, the article being preferably chosen from the group consisting of hoses, pipes, seals, O-rings, transmission belts, motor supports, insulators for electrical cables, shoe soles, semi-finished articles for pneumatic tires, semi-finished articles for non-pneumatic tires, non-pneumatic tires and pneumatic tires.

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), we mean 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).

The compounds 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. By “tire intended to equip a vehicle carrying heavy loads” we mean generically any tire fitted to heavy goods vehicles, vans, metros, buses, civil engineering vehicles, agricultural vehicles, airplanes and others. handling vehicles.

By “elastomeric matrix” or “elastomeric matrix” is meant all of the elastomer(s) present, functionalized or not, in the elastomeric composition.

By “majority” or “majority”, in the sense of the present invention, is meant that the compound is the majority among the compounds of the same type in the composition, that is to say that it is the one which represents the largest quantity by mass among compounds of the same type. In other words, the mass of this compound represents at least 51% of the total mass of compounds of the same type in the composition. For example, in a system comprising a single elastomer, it is the majority within the meaning of the present invention; and in a system comprising two elastomers, the majority elastomer represents more than half of the total mass of the elastomers, in other words the mass of this elastomer represents at least 51% of the total mass of the elastomers. In the same way, a so-called majority charge is that representing the greatest mass among the charges in the composition. In other words, the mass of this filler represents at least 51% of the total mass of the fillers in the composition.

All glass transition temperature “Tg” values are measured in a known manner by DSC (Differential Scanning Calorimetry) according to standard ASTM D3418 (2008).

DETAILED DESCRIPTION OF THE INVENTION

Functionalized diene elastomer

The elastomeric composition useful in the context of the present invention comprises a diene elastomer (that is to say one or more diene elastomer(s)) having a glass transition temperature less than or equal to -45°C measured according to standard ASTM D3418 (2008) and which comprises, in the middle of the chain, at least one Si-OR function in which R is a hydrogen atom or an alkyl group, substituted or not, preferably a C1- alkyl group C10, or even Ci-Cs or C1-C4, more preferably a methyl or an ethyl; the diene elastomer may further comprise at least one function, different from the Si-OR function, said different function comprising a heteroatom chosen from N, S, O and P.

A diene elastomer comprising, in the middle of the chain, at least one Si-OR function in which R is an alkyl group, substituted or not, or a hydrogen atom and which can furthermore comprise at least one function different from the Si-OR function comprising a heteroatom chosen from N, S, O and P will be designated in the following “functionalized diene elastomer”. The bonding of the Si-OR function to the elastomer chain is typically carried out by the silicon atom.

In other words, the diene elastomer comprises in the middle of the chain, at least one silicon atom substituted by at least one -OR group with R as described above.

A function different from the Si-OR function comprising a heteroatom chosen from N, S, O and P will be designated in the following “other function” or “other function comprising a heteroatom chosen from N, S, O and P” or “other different function.

The “middle of the chain” position is understood as opposed to the “end of the chain” position. The “mid-chain” position does not mean that the function is located precisely in the middle of the elastomeric main chain. When the Si-OR function is located in the middle of the chain, the silicon atom typically links the two branches of the main chain of the diene elastomer.

By “diene” elastomer (or indiscriminately rubber), 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-carbon double bonds, 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 such as EPDM do not fall within the previous definition and can be described in particular as “essentially saturated” diene elastomers (content of motifs of weak or very weak diene origin, always less than 15%).

By diene elastomer capable of being used in the elastomeric compositions according to the invention is particularly understood:

(a) any homopolymer of a diene monomer, conjugated or not, having from 4 to 18 carbon atoms;

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

The other monomer may be ethylene, an olefin or a diene, conjugated or not. As conjugated dienes suitable are conjugated dienes having 4 to 12 carbon atoms, 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 vinylaromatic compounds include, for example, styrene, ortho-, meta-, para-methylstyrene, the commercial “vinyl-toluene” mixture, and para-tertiobutylstyrene. As aliphatic a-monoolefins, acyclic aliphatic a-monoolefins having from 3 to 18 carbon atoms are particularly suitable.

Preferably, the diene elastomer is chosen from the group consisting of polybutadienes (BR), synthetic polyisoprenes (IR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers.

The functionalized diene elastomer is preferably a butadiene copolymer, more preferably a copolymer based on styrene and based on butadiene.

By “copolymer based on styrene and butadiene” is meant here a copolymer resulting from the polymerization of at least one styrene monomer and at least one butadiene monomer (and of course also any mixture of such copolymers). Suitable styrene monomers include styrene, methylstyrenes, para-tertiobutylstyrene, methoxystyrenes and chlorostyrenes. As butadiene monomers suitable in particular are 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C1-Cs alkyl)-1,3-butadienes such as for example 2 ,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1, 3-butadiene and an aryl-1,3-butadiene.

Preferably, the copolymer based on styrene and butadiene consists of styrene monomers and butadiene monomers, that is to say that the sum of the molar percentages of styrene monomers and butadiene monomers is equal to 100%. In other words, the functionalized diene elastomer is even more preferably a copolymer of styrene and butadiene (SBR).

In certain embodiments, the functionalized diene elastomer comprises at least one other function comprising at least one heteroatom chosen from N, S, O and P; this other function being different from the Si-OR function.

In the embodiments where the functionalized diene elastomer comprises at least one other function (function different from the Si-OR function), the other function is preferably carried by the silicon atom of the Si-OR function, i.e. directly or through of a spacer group. This spacer group is defined as being a divalent hydrocarbon atom or radical, linear or branched, aliphatic in C1-C18, preferably in C1-C12, more preferably in Ci-Ce, saturated or not, cyclic or not, or a radical divalent aromatic hydrocarbon in Ce-Cis. The hydrocarbon radical can optionally be substituted. Preferably, the spacer group is a divalent hydrocarbon radical, linear or branched, aliphatic in C1-C18, preferably in C1-C12, more preferably in Ci-Ce, saturated or not, more preferably still in C2 or C3.

As examples of functions comprising at least one heteroatom chosen from N, S, O and P, mention may be made of primary amines, secondary amines, tertiary amines, cyclic amines, isocyanates, imines, cyanos, thiols, carboxylates, epoxides, primary phosphines, secondary phosphines and tertiary phosphines.

Thus, as an amine function, mention may be made of amines substituted by C1-C10 alkyl groups, preferably C1-C4 alkyl, more preferably a methyl or ethyl radical, or cyclic amines forming a heterocycle containing an atom nitrogen and at least one carbon atom, preferably 2 to 6 carbon atoms. For example, the methylamino-, dimethylamino-, ethylamino-, diethylamino-, propylamino-, dipropylamino-, butylamino-, dibutylamino-, pentylamino-, dipentylamino-, hexylamino-, dihexylamino-, hexamethyleneamino- groups are suitable, preferably the diethylamino groups - and dimethylamino.

As an imine function, we can cite ketimines. For example, the groups (1,3-dimethylbutylidene)amino-, (ethylidene)amino-, (1-methylpropylidene)amino-, (4-N,N-dimethylaminobenzylidene)amino-, (1-methylpropylidene)amino-, (4-N,N-dimethylaminobenzylidene)amino-,

(cyclohexylidene)amino-, dihydroimidazole and imidazole.

Thus, as a carboxylate function, we can cite acrylates or methacrylates. Such a function is preferably a methacrylate.

As an epoxy function, mention may be made of epoxy or glycidyloxy groups.

As a secondary or tertiary phosphine function, mention may be made of phosphines substituted by C1-C10 alkyl groups, preferably C1-C4 alkyl, more preferably a methyl or ethyl radical, or diphenylphosphine. For example, the methylphosphino-, dimethylphosphino-, ethylphosphino-, diethylphosphino, ethylmethylphosphino- and diphenylphosphino- groups are suitable. More preferably, the other function different from the Si-OR function is preferably an amine, more preferably a primary amine or a secondary amine, more preferably a diethylamino- or dimethylamino- group.

In certain embodiments, the functionalized diene elastomer comprises at least one Si-OR function linked to the elastomer chain by the silicon atom and at least one other function different from the Si-OR function, preferably linked directly or by via a spacer group as defined above, more preferably via a divalent hydrocarbon radical, linear or branched, aliphatic at C1-C18, preferably at C1-C12, more preferably at Ci- This, saturated or not, even more preferably in C2 or C3, to the silicon atom of the Si-OR function. The other different function may be as defined above, more particularly an amine, preferably a primary amine or a secondary amine, very particularly the diethylamino- or dimethylamino- group, R may be as defined above.

In certain embodiments, the functionalized diene elastomer comprises at least one group comprising the Si-OR function, the group being represented by the formula (la):

(*— ) _a Si (OR)bX (la) in which:

* — represents the connection to an elastomeric chain;

R represents, independently of one another, a hydrogen atom or an alkyl group, substituted or unsubstituted, in C1-C10, or even in Ci-Cs, preferably a C1-C4 alkyl group, more preferably methyl or ethyl;

- , cyanos, thiols, carboxylates, epoxides, primary phosphines, secondary phosphines and tertiary phosphines; the other function which can be linked to the silicon atom via a spacer group as defined above, preferably the spacer being a divalent aliphatic radical, linear or branched in C1-C18, more preferably in C1-C12, more preferably in Ci-Ce; a is 2 and b is 1.

In other words, the elastomer comprises at least one silicon atom substituted by at least one -OR group, with R as described above, the substituted silicon atom corresponding to formula (la). According to a variant, X is an amine function, preferably a primary amine or a secondary amine, directly linked to the silicon atom itself directly integrated into the elastomer chain.

According to another variant, X is an amine function, preferably a primary amine or a secondary amine, linked to the silicon atom via a spacer group as defined above. According to a preferred variant, the spacer group is a divalent hydrocarbon radical, linear or branched, aliphatic in C1-C18, preferably in C1-C12, more preferably in Ci-Ce, saturated or not, more preferably an aliphatic divalent hydrocarbon radical, more preferably still a linear divalent hydrocarbon radical in C2 or C3.

More preferably, the other function represented by a divalent hydrocarbon radical, linear or branched, aliphatic in Ci-Ce, preferably in C2 or C3. Preferably,

In certain embodiments, the functionalized diene elastomer comprises at least one group of formula (la) in which:

- * — represents the connection to an elastomeric chain;

R represents, independently of one another, a hydrogen atom or a C1-C4 alkyl group;

_- a is 2 and b is 1.

(*— ) _a Si (OR)bX (la) in which:

* — represents the connection to an elastomeric chain;

R represents, independently of one another, a hydrogen atom or a C1-C4 alkyl group; - X represents a primary or secondary amine function; linked to the silicon atom via a linear or branched divalent hydrocarbon radical, aliphatic in CC ₆ ; a is 2, b is 1.

The mid-chain functionalized diene elastomer is preferably a copolymer based on styrene and butadiene. Even more preferably, the mid-chain functionalized diene elastomer is a copolymer of styrene and butadiene bearing a group of formula (la) in which X, R, a, b, and c are as defined above .

Functionalized diene elastomers comprising a Si-OR function in the middle of the chain, very particularly a group of formula (la), more preferably, copolymers of styrene and butadiene comprising a group of formula (la), are mainly obtained by functionalization of 'a living elastomer resulting from an anionic polymerization with a compound comprising an alkoxysilane group, in particular chosen from trialkoxysilane and dialkoxyalkylsilane compounds substituted by a group comprising another function linked directly or via a spacer group to the atom of silicon, the function and the spacer group being as defined above. It should be noted that it is known to those skilled in the art that when an elastomer is functionalized by reaction of a functionalizing agent on the living elastomer resulting from an anionic polymerization step, a mixture of functionalized species of this elastomer whose composition depends on the conditions of the modification reaction and in particular on the proportion of reactive sites of the functionalization agent relative to the number of living elastomer chains. This mixture includes functionalized species at the end of the chain, coupled, star-shaped and/or non-functionalized.

According to a particularly preferred variant, the functionalized diene elastomer comprises as the majority species the diene elastomer functionalized in the middle of the chain by an Si-OR function, very particularly a group of formula (la), linked to the two branches of the diene elastomer via the silicon atom. Even more particularly, the mid-chain functionalized diene elastomer represents at least 55% by weight of the functionalized diene elastomer.

As a functionalization or coupling agent, trialkoxysilane and dialkoxyalkylsilane compounds substituted by a group comprising another function linked directly or via a spacer group to the silicon atom are suitable, the function and the spacer group being as defined above. More particularly, mention may be made, as functionalizing agents, of (N,N-dialkylaminoalkyl)trialkoxysilanes, (N-alkylaminoalkyl)trialkoxysilanes whose secondary amine function is protected by a trialkyl silyl group and (aminoalkyl)trialkoxysilanes whose primary amine function is protected by two trialkyl silyl groups, the divalent hydrocarbon group making it possible to link the amine function to the trialkoxysilane group is the spacer group as described above, preferably a divalent hydrocarbon radical , linear or branched, aliphatic in C1-C18, preferably in C1-C12, more preferably in Ci-Ce, saturated or not, more particularly in C2 or C3. Advantageously, the functionalization agent is chosen from (N,N-dialkylaminoalkyl)trialkoxysilanes. More particularly, the functionalizing agent is 3-(N,N-dimethylaminopropyl)trimethoxysilane.

Functionalized diene elastomers comprising a Si-OR function in the middle of the chain, very particularly a group of formula (la), more preferably copolymers of styrene and butadiene can be prepared according to methods known to those skilled in the art, for example as described in W02009/133068 or in W02017001683A1.

Preferably, the diene elastomer functionalized in the middle of the chain by a Si-OR function, as defined above, more particularly with the group of formula (la) has a glass transition temperature, measured according to standard ASTM D3418-2008 , less than or equal to -45°C, more preferably included in a range ranging from -45°C to -110°C.

Preferably, the diene elastomer functionalized in the middle of the chain by a Si-OR function, as defined above, more particularly with the group of formula (la), has a number average molar mass Mn greater than 100,000 g/mol , more preferably its number average molar mass Mn is included in a range going from 110000 g/mol to 600000 g/mol; more preferably still from 120,000 g/mol to 300,000 g/mol: the Mn being measured by the SEC method as described below.

Preferably, the elastomeric composition useful in the context of the present invention comprises at least 50 phr of a functionalized diene elastomer as described above, more preferably at least 50 phr of a functionalized diene elastomer comprising at least one group comprising the Si-OR function, the group being represented by the formula (la) as defined above.

More preferably, the elastomeric composition useful in the context of the present invention may comprise at least 70 phr of a functionalized diene elastomer as described above, more preferably at least 70 phr of a functionalized diene elastomer comprising at least one group comprising the Si-OR function, the group being represented by formula (la) as defined above. Thus, the functionalized elastomer can advantageously be used in blending (mixing) with one or more other diene elastomer(s) different from the functionalized elastomer, preferably with one or more other(s). ) non-functionalized diene elastomer(s). In the case of cutting, it is understood that the sum of the different elastomers used is equal to 100 pce.

Thus, in addition to the functionalized elastomer as described above, the elastomeric composition may comprise one or more other non-functionalized diene elastomers. The other non-functionalized diene elastomer(s) may be chosen from the group formed by polybutadienes (BR), natural rubber (NR), synthetic isoprenes ( IR), butadiene copolymers other than butadiene-styrene copolymers, isoprene copolymers and mixtures of these polymers and copolymers.

Preferably, the elastomeric composition useful in the context of the present invention comprises from 50 to 100 phr of a functionalized diene elastomer as described above, more preferably from 50 to 100 phr of a functionalized diene elastomer comprising at least one group comprising the Si-OR function, the group being represented by formula (la) as defined above.

More preferably, the elastomeric composition useful in the context of the present invention comprises from 70 to 100 phr of a functionalized diene elastomer as described above, more preferably from 70 to 100 phr of a functionalized diene elastomer comprising at least one group comprising the Si-OR function, the group being represented by formula (la) as defined above.

In certain embodiments, the elastomeric composition useful in the context of the present comprises only the functionalized elastomer as described above, more preferably comprises only the functionalized diene elastomer comprising at least one group comprising the Si-OR function, the group being represented by the formula (la) as defined above.

Reinforcing filler

The elastomeric composition useful in the context of the present invention comprises a reinforcing filler, the reinforcing filler comprising at least one silicon-treated carbon black. In addition to the silicon-treated carbon black, the reinforcing filler may include one or more other reinforcing fillers.

Advantageously, it was found that a certain synergy could exist between the reinforcing filler comprising at least one carbon black treated with silicon as described below. below and at least one functionalized diene elastomer as defined above, more particularly the diene elastomer functionalized in the middle of the chain by a Si-OR function, very particularly the diene elastomer functionalized by the group of formula (la) such that defined above; this synergy resulting in particular in an improvement in rolling resistance (reduction in hysteresis), an improvement in reinforcement and rigidity compared to the elastomeric compositions of the prior art.

The term “reinforcing filler” designates any type of filler known for its ability to reinforce an elastomeric composition usable in particular for the manufacture of tires, for example organic fillers such as carbon black, or inorganic fillers such as silica or alumina.

In addition to the carbon black treated with silicon, the elastomeric composition can therefore also comprise at least one second reinforcing filler different from the carbon black treated with silicon, this second reinforcing filler being chosen from the group consisting of silicas, aluminas and blacks. of carbon different from a carbon black treated with silicon.

Those skilled in the art will be able to adapt the total rate of reinforcing filler, including the rate of carbon black treated with silicon, according to the relevant use of the elastomeric composition.

In certain embodiments, the level of reinforcing filler in the elastomeric composition useful in the context of the invention is included in a range ranging from 25 to 85 phr, preferably from 35 to 75 phr.

Preferably, the silicon-treated carbon black represents more than 30% by weight, more preferably represents more than 50% by weight, even more preferably represents more than 70% by weight, more preferably represents more than 90% by weight of the total weight of the reinforcing load.

Thus, preferably, the level of reinforcing filler in the elastomeric composition useful in the context of the invention is included in a range ranging from 25 to 85 phr, the carbon black treated with silicon representing more than 30% by weight, more preferably representing more than 50% by weight, more preferably still representing more than 70% by weight, more preferably representing more than 90% by weight of the total weight of the reinforcing filler.

Thus, more preferably, the rate of reinforcing filler in the elastomeric composition useful in the context of the invention comprising at least one carbon black treated with silicon is included in a range ranging from 35 to 75 phr, the treated carbon black silicon representing more than 30% by weight, more preferably representing more than 50% by weight, more preferably still representing more than 70% by weight, more preferably representing more than 90% by weight of the total weight of the reinforcing filler.

In some embodiments, the reinforcing filler is only silicon-treated carbon black. In certain embodiments, the elastomeric composition comprises from 25 to 85 phr, preferably from 35 to 75 phr, of reinforcing filler, the reinforcing filler being carbon black treated with silicon. It must then be understood that the elastomeric composition, in this particular embodiment, comprises carbon black treated with silicon as the only reinforcing fillers (the elastomeric composition therefore does not include inorganic reinforcing fillers and other organic reinforcing fillers).

The reinforcing fillers can be as described below.

Silicon-treated carbon black

The elastomeric composition useful in the context of the invention comprises as reinforcing filler at least one carbon black treated with silicon.

For the purposes of the present invention, the term “silicon-treated carbon black” means a carbon black which comprises silicon either on the surface of the carbon black aggregate or inside the black aggregate. of carbon.

In silicon-treated carbon black, the silicon-containing species, such as silicon oxide or carbide, is distributed throughout at least a portion of the carbon black aggregate as an intrinsic part of the black of carbon, either on the surface of the carbon black aggregate, or inside the carbon black aggregate. Silicon-treated carbon blacks are not aggregates of carbon black that have been coated or otherwise modified with silicon. Silicon-treated carbon blacks actually represent two-phase aggregate particles; one phase is carbon, which will always be present as graphitic crystallite and/or amorphous carbon, while the second phase is silica, and optionally other silicon-containing species. Thus, the silicon-containing species phase is an intrinsic part of the aggregate; either on the surface of the aggregate or inside the aggregate.

When silicon-treated carbon black is examined under STEM-EDX, the silicon signal corresponding to the silicon-containing species is found to be present in the individual carbon black aggregates. By comparison, for example, in a physical mixture of silica and carbon black, STEM-EDX examination reveals clearly separated aggregates of silica and carbon black. The manufacture and properties of these silicon-treated carbon blacks are described in particular in patent US6028137.

The silicon-treated carbon black useful in the context of the present invention may contain from 3% to 20% silicon by weight, preferably from 3.5% to 10% by weight, more preferably from 4% to 8% by weight, based on the weight of silicon-treated carbon black.

The silicon-treated carbon black useful in the context of the present invention may have a STSA surface area measured according to ASTM D6556-17 in a range from 50 m ² /g to 170 m ² /g, preferably 90 m ² /g to 150 m ² /g.

The silicon-treated carbon black useful in the context of the present invention may have a COAN compressed oil absorption index measured according to standard D3493-18 in a range from 70 ml/100g to 130 ml/100g, more preferably from 80 ml/100g to 120 ml/100g.

Even more preferably, the silicon-treated carbon black useful in the context of the present invention may have a STSA surface area measured according to standard ASTM D6556-17 in the range from 50 m ² /g to 170 m ² /g and may have a COAN compressed oil absorption index measured according to standard D3493-18 in a range from 70 ml/100g to 130 ml/100g.

Even more preferably, the silicon-treated carbon black useful in the context of the present invention may have a STSA surface area measured according to standard ASTM D6556-17 in the range from 90 m ² /g to 150 m ² /g and may have a COAN compressed oil absorption index measured according to standard D3493-18 within a range of 80 ml/100g to 120 ml/100g.

Ecoblack™ silicon-treated carbon blacks are available, for example, from Cabot Corporation.

Carbon black

The elastomeric composition useful in the context of the invention may further comprise a carbon black (that is to say one or more carbon blacks) different from the carbon black treated with silicon.

As carbon blacks other than a carbon black treated with silicon, all carbon blacks are suitable, in particular the blacks conventionally used in tires or their treads, in particular industrial carbon blacks, more specifically so-called “furnace” carbon blacks.

Among the carbon blacks not treated with silicon, 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, N 134, N234, N326, N330, N339, N347, N375, N550, N683, N772.

These carbon blacks not treated with silicon can be used in the 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 WO97/36724-A2 or W099/16600-A1) .

Reinforcing inorganic filler

The elastomeric composition useful in the context of the invention may comprise a silica or an alumina (that is to say one or more silicas or aluminas) which are reinforcing inorganic fillers.

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 means other than an intermediate coupling agent, an elastomeric 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.

As reinforcing inorganic fillers suitable in particular are mineral fillers of the siliceous type, preferably silica (SiCh) or of the aluminous type, in particular alumina (AI2O3). 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 area as well as a CTAB specific surface area 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 W003/016215-A1 and W003/016387-A1. Among the commercial HDS silicas, one can in particular use the silicas “Ultrasil ® 5000GR”, “Ultrasil ® 7000GR” from the company Evonik, the silicas “Zeosil ® 1085GR”, “Zeosil® 1115 MP”, “Zeosil® 1165MP”, “ Zeosil® Premium 200MP”, “Zeosil® H RS 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” silicas -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 elastomeric compositions, mineral fillers of the aluminous type may also be cited, 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 WO99/28376-A2, WOOO/73372-A1, WO02/053634-A1, WG2004/003067- A1, WG2004/056915-A2,

US6610261-B1 and US6747087-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.

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 bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT sold under the name “Si69” by the company Evonik or bis disulfide -(triethoxysilylpropyl), abbreviated 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.

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 reinforcing inorganic filler used in the elastomeric composition.

The elastomeric composition may also contain, in addition to the coupling agents, coupling activators, inorganic charge recovery agents or more generally processing aid agents capable in a known manner, thanks to an improvement in the 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 hydrolysable POS, for example a,œ-dihydroxy-polyorganosiloxanes (in particular a ,œ-dihydroxy-polydimethylsiloxanes). Other organic loads

The elastomeric composition useful in the context of the invention may comprise a reinforcing organic filler of functionalized polyvinyl type as described in applications W02006/069792-A1, W02006/069793-A1, W02008/003434-A1 and W02008/003435-A1 .

Reticulation system

The elastomeric 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 elastomeric 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 within a range ranging from 0.5 to 12 pce, in particular from 1 to 10 pce.

The vulcanization accelerator is used at a preferential rate within a range ranging from 0.5 to 10 phr, more preferably from 0.5 to 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"), disulfide tetrabenzylthiuram ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds.

Common additives and processing agents

The elastomeric 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 elastomeric compositions for tires, such as for example plasticizing agents (such as plasticizing oils and/or plasticizing resins), non-reinforcing fillers, pigments, raw tack promoting agents (i.e. tackifying agent), pro-oxidant metal salts, 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).

Preferably, the level of plasticizing agent(s) in the elastomeric composition useful in the context of the invention is included in a range ranging from 0 to 20 phr, more preferably in a range ranging from 0 to 10 phr.

Manufacturing of compositions

The elastomeric 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 "nonproductive" phase), which can be carried out in a single thermomechanical step during which it is introduced into a suitable mixer such as a usual internal mixer (for example of the 'type Banbury'), all the necessary constituents, in particular the functionalized diene elastomer, the reinforcing filler(s) including carbon black treated with silicon, any other various additives, with the exception of the crosslinking system. The incorporation of the reinforcing filler into the functionalized diene elastomer can be carried out one or more times by thermomechanical mixing. The non-productive phase is carried out at high temperature, up to a maximum temperature within a range of 110°C to 200°C, for a duration generally within a range of 2 to 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 less than 120°C, for example ranging from 40°C to 100°C. We then incorporate the crosslinking system, and everything is then mixed for a few minutes, for example 5 to 15 min.

The final elastomeric 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 usable rubber. for example as a tread of a tire, in particular as a tread of a tire of a vehicle carrying heavy loads, in particular of a heavy goods vehicle or a civil engineering vehicle.

The elastomeric 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 elastomeric composition can be carried out in a manner known to those skilled in the art, for example at a temperature in a range from 130°C to 200°C, preferably under pressure, for a sufficient time which can vary. for example from 5 to 90 min.

RUBBER ITEMS

Another object of the present invention relates to a rubber article comprising at least one elastomeric composition as defined above.

The rubber article may be any type of article such as a hose, pipe, gasket, O-ring, transmission belt, engine mount, electrical cable insulation, shoe sole, a semi-finished article for pneumatic tires, a semi-finished article for non-pneumatic tires, a pneumatic tire or a non-pneumatic tire.

Preferably, the rubber article is chosen from the group consisting of semi-finished articles for pneumatic tires, semi-finished articles for non-pneumatic tires, pneumatic tires and non-pneumatic tires.

Semi-finished products for pneumatic tires or non-pneumatic tires are rubber products intended for the manufacture of pneumatic tires or non-pneumatic tires. It can be any type of rubber band, such as treads, underlays, etc.

More preferably, the elastomeric composition as defined above useful in the context of the invention constitutes all or part of said semi-finished article. Preferably, the semi-finished article for pneumatic tires or for non-pneumatic tires is a tread.

In known manner, the tread of a pneumatic or non-pneumatic tire comprises a rolling surface intended to be in contact with the ground when the pneumatic tire or the non-pneumatic tire rolls. The tread is provided with a sculpture including in particular sculpture elements or elementary blocks delimited by various grooves.

Advantageously, the elastomeric composition as defined above useful in the context of the invention is present in the tread of the pneumatic tire or of the non-pneumatic tire, preferably in the radially external part of the tread, intended to be in contact with the ground when the pneumatic or non-pneumatic tire rolls. Even more preferably, the elastomeric composition as defined above useful in the context of the invention constitutes all or part of the tread, in particular for pneumatic tires or for non-pneumatic tires.

By “pneumatic tire” is meant a tire intended to form a cavity by cooperating with a support element, for example a rim, this cavity being able to be pressurized to a pressure greater than atmospheric pressure.

In contrast, a “non-pneumatic tire” is a tire that supports the load of a vehicle by means other than pressurized inflation gas. Thus, a non-pneumatic tire is a toric body constituted by at least one polymeric material, intended to perform the function of a tire but without being subjected to inflation pressure. A non-pneumatic tire can be solid or hollow. A hollow non-pneumatic tire may contain air, but at atmospheric pressure, that is to say it does not have pneumatic stiffness provided by an inflation gas at a pressure higher than atmospheric pressure. Non-pneumatic tires are described for example in documents WO 03/018332 and FR2898077.

Pneumatic or non-pneumatic tires are intended to equip vehicles of all types in particular.

Preferably, the rubber article according to the invention is a semi-finished article for a tire, preferably a tread, such as a tread in particular made up in whole or in part of at least one elastomeric composition such as defined above. Even more preferably, the semi-finished article above is a semi-finished article for industrial vehicles such as heavy goods vehicles, vans, agricultural vehicles, buses, subways, civil engineering vehicles, airplanes and other handling vehicles.

Even more preferably; the rubber article according to the invention is a pneumatic tire comprising at least one elastomeric composition, in particular in its tread, said elastomeric composition constituting all or part of said tread. Even more preferably, the rubber article is a pneumatic tire for industrial vehicles such as heavy goods vehicles, vans, agricultural vehicles, buses, metros, civil engineering vehicles, airplanes and other handling vehicles. . The pneumatic tire can be manufactured according to any process well known to those skilled in the art.

Preferably, the rubber article is a pneumatic or non-pneumatic tire whose tread is made up entirely or in part of at least one elastomeric composition according to the invention.

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

EXAMPLES

1. Measuring method

1.1 Measurement of number average molar masses (Mn), weight average (Mw) and the polydispersity index for elastomers

Size exclusion chromatography or SEC (Size Exclusion Chromatography) is used. SEC makes it possible to separate macromolecules in solution according to their size through columns filled with a porous gel. The macromolecules are separated according to their hydrodynamic volume, the largest being eluted first.

Without being an absolute method, SEC makes it possible to understand the distribution of molar masses of an elastomer. From commercial standard products, the different average molar masses in number (Mn) and weight (Mw) can be determined and the polymolecularity index (Ip = Mw/Mn) calculated via a so-called MOORE calibration.

Preparation of the elastomer sample to be tested:

There is no particular treatment of the elastomer sample before analysis. This is simply dissolved at a concentration of approximately 1 g/l, in chloroform or in the following mixture: tetrahydrofuran + 1% vol. of diisopropylamine + 1% vol. triethylamine + 1% vol. of distilled water (% vol. =% volume). Then, the solution is filtered through a filter with a porosity of 0.45 μm before injection.

SEC Analysis:

The equipment used is a “WATERS alliance” chromatograph. The elution solvent is the following mixture: tetrahydrofuran + 1% vol. of diisopropylamine + 1% vol. triethylamine or chloroform depending on the solvent used to dissolve the elastomer. The flow rate is 0.7 ml/min, the system temperature is 35°C and the analysis time is 90 min. We use a set of four WATERS columns in series, with the trade names “STYRAGEL HMW7”, “STYRAGEL HMW6E” and two “STYRAGEL HT6E”.

The injected volume of the elastomer sample solution is 100 pL. The detector is a “WATERS 2410” differential refractometer with a wavelength of 810 nm. The chromatographic data processing software is the “WATERS EM POWER” system.

The average molar masses calculated relate to a calibration curve produced from commercial standard polystyrene “PSS READY CAL-KIT”.

1.2 Analysis of the function of the elastomer

The NMR analyzes are carried out on a 500 MHz BRUKER spectrometer equipped with a 5 mm BBIz “broadband” probe. For the quantitative ¹ H NMR experiment, the sequence uses a 30° pulse and a repetition delay of 2 seconds. The samples are solubilized in carbon disulfide (CS2). 100 μL of deuterated cyclohexane (CODI2) are added for the lock signal. The ¹ H NMR spectrum makes it possible to quantify the (CHs)2Si function by integration of the characteristic signal of the SiCHs protons around 5 = 0 ppm.

The ² D ¹ H- ²⁹ Si NMR spectrum makes it possible to verify the nature of the function thanks to the chemical shift values of the silicon nuclei and protons in the 2J neighborhood (via 2 bonds).

1.3 Analysis of the microstructure of the elastomer

Near infrared spectroscopy (N IR) is used to quantitatively determine the mass content of styrene in the elastomer as well as its microstructure (relative distribution of 1,2-vinyl, 1,4-trans and 1,4 cis butadiene units). The principle of the method is based on the Beer-Lambert law generalized to a multicomponent system. The method being indirect, it uses multivariate calibration [Vilmin, F.; Dussap, C; Coste, N. Applied Spectroscopy 2006, 60, 619-29] produced using standard elastomers of composition determined by ¹³ C NMR. The styrene content and the microstructure are then calculated from the NIR spectrum of a film of elastomer approximately 730 μm thick. Spectrum acquisition is carried out in mode transmission between 4000 and 6200 cm ^-1 with a resolution of 2 cm ^-1 , using a Bruker Tensor 37 Fourier transform near-infrared spectrometer equipped with an InGaAs detector cooled by the Peltier effect.

1.4 Dynamic properties

The dynamic properties are measured on a viscoanalyzer (Metravib VA4000), according to the ASTM D 5992-96 standard. The response of a sample of the vulcanized composition (cylindrical test pieces 4 mm thick and 400 mm ² in section) is recorded, subjected to a sinusoidal stress in alternating simple shear, at a frequency of 10 Hz, at a temperature of 60 °C.

For measurements of the complex dynamic shear modulus (G*) and the loss factor tan(delta), a strain amplitude sweep is carried out from 0.1% to 100% peak-peak (forward cycle), then from 100 % to 0.1% peak-peak (return cycle). For the return cycle, we indicate the maximum value of tan(delta) observed, denoted tan(delta)max; as well as the module G* at 50% deformation noted G*50% at 60°C.

The tan(delta)max value is representative of the hysteresis of the material and in this case the rolling resistance: the lower the tan(delta)max value, the better the rolling resistance. The values of G*50% measured at 60°C are representative of the rigidity, that is to say the resistance to deformation: the higher the value of G*50% at 60°C, the greater the rigidity of the material is important, and therefore the better the resistance to wear. All values are indicated in base 100 relative to a given control.

1.5 Tensile Tests

Tensile tests make it possible to determine the elastic stresses and the breaking properties. Unless otherwise indicated, they are carried out in accordance with French standard N F T 46-002 (1988).

Processing the traction records makes it possible in particular to trace the modulus curve as a function of elongation. The modulus used here is the nominal (or apparent) secant modulus measured at first elongation at a temperature of 60°C, calculated by going back to the initial section of the specimen. We measure in first elongation the nominal secant modulus (or apparent stress, in MPa) at 10% and 300% elongation, at 60°C, noted respectively MSA10 and MSA300.

All values are indicated in base 100 relative to a given control. A value greater than 100 indicates a value greater than that of the control. 2. Preparation of compositions

The manufacture of the elastomeric compositions is prepared in the following manner: the functionalized diene elastomer or the non-functionalized diene elastomer is introduced into an internal mixer, filled to 70% and whose initial tank temperature is approximately 100°C. . Then, for each of the elastomeric compositions, the reinforcing filler(s) to be tested are introduced, then after one to two minutes of mixing, 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 5 minutes, until a maximum drop temperature of 160°C is reached. The mixture thus obtained is recovered, cooled and then added the vulcanization system (sulfur and the sulfenamide type accelerator) on an external mixer (homo-finisher) at 30°C, mixing the whole (productive phase) for about 5 to 6 minutes.

The elastomeric compositions thus obtained are then calendered in the form of plates (thickness of 2 to 3 mm) for the measurement of their physical or mechanical properties. The formulations of the elastomeric compositions prepared are described in Table 1 (components and contents - unless otherwise indicated, the contents are expressed in pce).

The rubber properties of these compositions are measured after cooking at 150°C for 30 minutes. The results obtained are shown in Table 1.

Table 1: formulation of the different compositions and properties in the cooked state

(1) Diene elastomer: SBR solution, non-extended, non-functional, with 24% by weight relative to the butadiene part of 1,2 polybutadiene units; 26.5% by weight relative to the total weight of the elastomer of styrene patterns and a Tg = -48°C; Mn measured by SEC equal to approximately 160,000g/mol;

(2) Diene elastomer: SBR solution, not extended, functionalized, with an amino-alkoxysilane function in the middle of the chain, with 24% by weight relative to the butadiene part of 1,2 polybutadiene units; 26.5% by weight relative to the total weight of the elastomer of styrene patterns and a Tg = -48°C; Mn measured by SEC equal to approximately 160,000 g/mol, this copolymer was synthesized according to the process described in document WO2009/133068;

(3) Conventional carbon black, not treated with silicon, grade N134 according to standard ASTM D-1765-2019, not treated with silicon, having an STSA measured according to standard ASTM D6556-17 of 137 m ² /g and a COAN measured according to ASTM D3493-18 of 103 ml/100 g; (4) Carbon black treated with silicon marketed by the company Cabot under the commercial reference “Ecoblack CRX2125”; having an STSA measured according to standard ASTM D6556-17 of 132 m ² /g and a COAN measured according to standard ASTM D3493-18 of 110 ml/100 g and a silicon content of 5% by weight relative to the weight of black silicon-treated carbon; (5) 2,2,4-trimethyl-1,2-dihydroquinoline from the company Flexsys;

(6) N-1,3-dimethylbutyl-N-phenyl-para-phenylene diamine from the company Flexsys;

(7) N-cyclohexyl-2-benzothiazyl-sulfenamide from the company Flexsys.

The tests demonstrate an improvement in the stiffness/hysteresis/reinforcement compromise for the elastomeric compositions in accordance with the invention (A1) compared to elastomeric compositions not in accordance with the invention (C1, C2 and C3).

According to Table 1, a reduction in hysteresis is noted for the composition C2 not in accordance with the invention comprising a carbon black treated with silicon compared to the non-compliant composition C1 comprising a usual carbon black. We also observe a reduction in rigidity and reinforcement.

The use of a usual carbon black with a functionalized elastomer within the meaning of the present invention (non-compliant composition C3) makes it possible to obtain, compared to the non-compliant composition C1, a reduction in hysteresis but also a reduction of the MSA300.

Surprisingly, the elastomeric composition A1 in accordance with the invention comprising a functionalized diene elastomer within the meaning of the present invention and a carbon black treated with silicon, presents, compared to the compositions not in accordance with the invention C1 to C3, a reduction significant improvement in hysteresis (favorable for rolling resistance) and a significant improvement in stiffness and reinforcement properties (favorable for wear resistance properties).

Claims

1. Elastomeric composition based on: a diene elastomer having a glass transition temperature less than or equal to -45°C measured according to standard ASTM D3418-2008 and comprising, in the middle of the chain, at least one Si-OR function in which R is an alkyl group, substituted or not, or a hydrogen atom; a reinforcing filler comprising at least one silicon-treated carbon black; and a crosslinking system.

2. Elastomeric composition according to claim 1, in which the diene elastomer further comprises at least one other function different from the Si-OR function, said different function comprising a heteroatom chosen from N, S, O or P, preferably said function is carried by the silicon atom of the Si-OR function, directly or via a spacer.

3. Elastomeric composition according to any one of the preceding claims, in which the diene elastomer comprises in the middle of the chain a group comprising the Si-OR function, the group being represented by the formula (la):

(*— ) _a Si (OR)bX (la) in which:

- * — represents the bond to an elastomeric chain;

R represents, independently of one another, a hydrogen atom or an alkyl group, substituted or unsubstituted, in C1-C10, or even in Ci-Cs, preferably a hydrogen atom or an alkyl group in C1-C4,

- , cyanos, thiols, carboxylates, epoxides, primary phosphines, secondary phosphines and tertiary phosphines; the other function can be linked to the silicon atom via a spacer group; a is 2 and b is 1.

4. Elastomeric composition according to one of claims 2 or 3, in which the spacer is a divalent, linear or branched, aliphatic C1-C18 hydrocarbon radical, of preferably in C1-C12, more preferably in Ci-Ce, saturated or not, or a divalent aromatic hydrocarbon radical in Ce-Cis.

5. Elastomeric composition according to claim 3 or 4, in which the function X is a primary, secondary or tertiary amine function, preferably a primary or secondary amine function.

6 Elastomeric composition according to any one of claims 3 to 5, in which in formula (la):

- * — represents the connection to an elastomeric chain;

_- a is 2 and b is 1.

7. Elastomeric composition according to any one of the preceding claims, in which the diene elastomer is a copolymer based on butadiene and based on styrene, more preferably is a copolymer of styrene and butadiene.

8. Elastomeric composition according to any one of the preceding claims, in which the functionalized diene elastomer has a number average molar mass Mn greater than 100,000 g/mol, more preferably its number average molar mass Mn is within a range ranging from 110,000 g/mol to 600,000 g/mol; more preferably still from 120,000 g/mol to 300,000 g/mol.

9. Elastomeric composition according to any one of the preceding claims, in which the silicon-treated carbon black has an STSA surface area measured according to ASTM D6556-17 in a range from 50 m ² /g to 170 m ² / g, preferably from 90 m ² /g to 150 m ² /g.

10. Elastomeric composition according to any one of the preceding claims, in which the carbon black treated with silicon has a compressed oil absorption index COAN measured according to standard D3493-18 within a range of 70 ml/100g at 130 ml/100g, more preferably from 80 ml/100g to 120 ml/100g.

11. Elastomeric composition according to any one of the preceding claims, in which the carbon black treated with silicon contains from 3% to 20% silicon by weight, preferably from 3.5% to 10% by weight, more preferably from 4% to 8% by weight, based on the weight of the silicon-treated carbon black.

12. Elastomeric composition according to any one of the preceding claims, in which the reinforcing filler level is included in a range ranging from 25 to 85 phr, preferably from 35 to 75 phr.

13. Elastomeric composition according to any one of the preceding claims, in which the carbon black treated with silicon represents more than 30% by weight, more preferably represents more than 50% by weight, even more preferably represents more than 70% by weight , even more preferably represents more than 90% by weight of the total weight of the reinforcing filler.

14. Rubber article comprising at least one elastomeric composition according to any one of claims 1 to 13; the article being preferably chosen from the group consisting of hoses, pipes, seals, O-rings, transmission belts, engine supports, insulators for electrical cables, shoe soles, semi-finished articles -finished items for pneumatic tires, semi-finished articles for non-pneumatic tires, non-pneumatic tires and pneumatic tires.

15. Rubber article according to claim 14, said article being a pneumatic or non-pneumatic tire whose tread consists entirely or in part of at least one elastomeric composition according to any one of claims 1 to 13.