Elastomer compositions comprising a pyrolysis carbon black

Abstract

The present disclosure relates to an elastomer composition based on: - at least one diene elastomer comprising, at the chain end or 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 pyrolysis carbon black; and - a crosslinking system.

Description

[0001] ELASTOMERIC COMPOSITIONS COMPRISING A PYROLYSIS CARBON BLACK

[0002] FIELD OF THE INVENTION

[0003] 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.

[0004] TECHNOLOGICAL BACKGROUND

[0005] Ideally, the elastomeric compositions constituting the treads of pneumatic or non-pneumatic tires must meet a large number of technical requirements, often contradictory, including high wear resistance while providing the tire with low rolling resistance. To increase the rigidity of an elastomeric composition, it is known, for example, to increase the level of reinforcing fillers. However, this solution has the disadvantage of increasing the hysteresis of the elastomeric composition.

[0006] Furthermore, in recent years, limiting the environmental impact of the manufacture and use of tires has become a major issue for manufacturers in the sector.

[0007] Research and development initiatives to produce tires from recycled materials have multiplied. For example, it has been proposed to use pyrolysis carbon blacks as a total or partial replacement for conventional tire-grade carbon blacks used as a reinforcing filler in the elastomeric compositions constituting the tire, particularly treads. While this solution offers gains in hysteresis (rolling resistance), these are obtained at the cost of a reduction in rigidity, resulting in lower tire wear resistance.

[0008] The loss of rigidity observed by the use of pyrolysis carbon blacks can be compensated in particular by increasing the level of reinforcing filler in the elastomeric compositions. However, this increase in the level of reinforcing fillers causes an increase in the hysteresis of the composition and therefore a risk of penalizing the rolling resistance properties, in particular of a pneumatic or non-pneumatic tire.

[0009] There is therefore still a need to provide elastomeric compositions that reduce the environmental footprint, by incorporating recycled materials and which satisfy a stiffness / hysteresis compromise while maintaining other properties, these compositions being particularly useful for forming all or part of the tread of a pneumatic or non-pneumatic tire.

[0010] BRIEF DESCRIPTION OF THE INVENTION

[0011] The present invention relates to an elastomeric composition based on: at least one diene elastomer comprising, at the end of the chain or 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 pyrolysis carbon black; and a crosslinking system.

[0012] The present invention also relates to a rubber article comprising at least one such elastomeric composition, the article preferably being selected from the group consisting of hoses, pipes, seals, O-rings, transmission belts, engine mounts, insulators for electric cables, shoe soles, semi-finished articles for pneumatic tires, semi-finished articles for non-pneumatic tires, non-pneumatic tires and pneumatic tires.

[0013] Other aspects of the invention are as described below and in the claims.

[0014] DEFINITIONS

[0015] The expression "composition based on" means a composition comprising the mixture and / or the in situ reaction product of the different constituents used, some of these constituents being able to react and / or being intended to react with each other, at least partially, during the different phases of manufacture of the composition; the composition can thus be in a totally or partially crosslinked state or in a non-crosslinked state.

[0016] The expression "part by weight per hundred parts by weight of elastomer" (or pce) means the part by mass per hundred parts by mass of elastomer or rubber, the two terms being synonymous.

[0017] In this document, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0018] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​going from more than a to less than b (i.e., excluding the limits a and b) while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​going from a to b (i.e., including the strict limits a and b).

[0019] The compounds mentioned in the description may be of fossil or bio-sourced origin. In the latter case, they may be partially or totally derived from biomass or obtained from renewable raw materials derived from biomass. This includes polymers, plasticizers, fillers, etc.

[0020] 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 other handling vehicles.

[0021] By “elastomer matrix” or “elastomeric matrix” is meant all of the elastomer(s) present, functionalized or not, in the elastomeric composition.

[0022] By "predominantly" or "in a majority capacity", it is meant, within the meaning of the present invention, that the compound is in 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 the compounds of the same type. In other words, the mass of this compound represents at least 51% of the total mass of the compounds of the same type in the composition. For example, in a system comprising a single elastomer, this is in 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 filler is that representing the largest mass among the fillers in the composition.In other words, the mass of this filler represents at least 51% of the total mass of fillers in the composition.

[0023] All glass transition temperature “Tg” values ​​are measured in a known manner by DSC (Differential Scanning Calorimetry) according to ASTM D3418 (2008).

[0024] DETAILED DESCRIPTION OF THE INVENTION

[0025] Surprisingly, the inventors have discovered that the specific combination of at least one diene elastomer as described below, a reinforcing filler as described below and a crosslinking system makes it possible to obtain an elastomeric composition meeting the expressed needs. In particular, the elastomeric composition can be used in a pneumatic or non-pneumatic tire, in particular in a tread, in particular for a pneumatic or non-pneumatic tire fitted to vehicles carrying heavy loads. The proposed solution makes it possible to reduce the environmental footprint of tires by incorporating recycled materials and to obtain a good stiffness / hysteresis compromise (wear resistance / rolling resistance).

[0026] Thus, the present invention relates to an elastomeric composition based on: at least one diene elastomer comprising, at the end of the chain or 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 pyrolysis carbon black; and a crosslinking system.

[0027] Diene elastomer

[0028] The elastomeric composition useful in the context of the present invention comprises at least one diene elastomer (i.e. one or more diene elastomers) comprising, at the end of the chain or 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-C10, or even C1-C8 or C1-C4 alkyl group, 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.

[0029] A diene elastomer comprising, at the end of the chain or 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 may also comprise at least one function different from the Si-OR function comprising a heteroatom chosen from N, S, O and P will be referred to hereinafter as a “functionalized diene elastomer”. The bonding of the Si-OR function to the elastomer chain is typically carried out by the silicon atom.

[0030] In other words, the diene elastomer comprises at the end of the chain or in the middle of the chain, at least one silicon atom substituted by at least one -OR group with R as described previously.

[0031] A function other than 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”.

[0032] The "mid-chain" position is understood as opposed to the "end-of-chain" position. The "mid-chain" position does not mean that the function is located precisely in the middle of the elastomer 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 diene elastomer main chain.

[0033] By "diene" elastomer (or indistinctly rubber), whether natural or synthetic, must be understood in a known manner an elastomer consisting at least in part (i.e., a homopolymer or a copolymer) of diene monomer units (monomers carrying two carbon-carbon double bonds, conjugated or not).

[0034] These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". "Essentially unsaturated" generally means a diene elastomer derived at least in part from conjugated diene monomers, having a content of units or patterns of diene origin (conjugated dienes) which is greater than 15% (mol %); thus, diene elastomers such as butyl rubbers or copolymers of dienes and alpha-olefins such as EPDM do not fall within the previous definition and can be described in particular as "essentially saturated" diene elastomers (low or very low content of patterns of diene origin, always less than 15%).

[0035] The term diene elastomer capable of being used in the elastomeric compositions in accordance with the invention is particularly understood to mean:

[0036] (a) - any homopolymer of a diene monomer, conjugated or not, having from 4 to 18 carbon atoms;

[0037] (b) - any copolymer of a diene, conjugated or not, having from 4 to 18 carbon atoms and at least one other monomer.

[0038] The other monomer can be ethylene, an olefin or a diene, conjugated or not.

[0039] Suitable conjugated dienes are conjugated dienes having 4 to 12 carbon atoms, in particular 1,3-dienes, such as 1,3-butadiene and isoprene.

[0040] Suitable olefins are vinylaromatic compounds having 8 to 20 carbon atoms and aliphatic α-monoolefins having 3 to 12 carbon atoms. Suitable vinylaromatic compounds are, for example, styrene, ortho-, meta-, para-methylstyrene, the commercial mixture "vinyl-toluene", para-tert-butylstyrene. Suitable aliphatic α-monoolefins are, in particular, acyclic aliphatic α-monoolefins having 3 to 18 carbon atoms.

[0041] 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.

[0042] The functionalized diene elastomer is preferably a butadiene copolymer, more preferably a styrene-based and butadiene-based copolymer.

[0043] By "styrene and butadiene-based copolymer" 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 in particular styrene, methylstyrenes, para-tert-butylstyrene, methoxystyrenes and chlorostyrenes. Suitable butadien monomers include, in particular, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C1-C8 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, i.e. 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).

[0044] 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.

[0045] In 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, either directly or via a spacer group. This spacer group is defined as being a divalent, linear or branched, aliphatic C1C, preferably C1-C12, more preferably C1-C 6, saturated or unsaturated, cyclic or not, or a divalent aromatic hydrocarbon radical in Ce-C . The hydrocarbon radical may 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 unsaturated, more preferably still in C2 or in C3.

[0046] Examples of functions comprising at least one heteroatom chosen from N, S, O and P include primary amines, secondary amines, tertiary amines, cyclic amines, isocyanates, imines, cyanos, thiols, carboxylates, epoxides, primary phosphines, secondary phosphines and tertiary phosphines.

[0047] Thus, as 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 a nitrogen atom and at least one carbon atom, preferably from 2 to 6 carbon atoms. For example, methylamino-, dimethylamino-, ethylamino-, diethylamino-, propylamino-, dipropylamino-, butylamino-, dibutylamino-, pentylamino-, dipentylamino-, hexylamino-, dihexylamino-, hexamethyleneamino- groups, preferably diethylamino- and dimethylamino groups. As imine function, mention may be made of ketimines. For example, the groups (1,3-dimethylbutylidene)amino-, (ethylidene)amino-, (1-methylpropylidene)amino-, (4-N,N-dimethylaminobenzylidene)amino-, are suitable.

[0048] (cyclohexylidene)amino-, dihydroimidazole and imidazole.

[0049] Thus, as carboxylate function, mention may be made of acrylates or methacrylates. Such a function is preferably a methacrylate.

[0050] As epoxide functions, we can cite epoxy or glycidyloxy groups.

[0051] As 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.

[0052] 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.

[0053] 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 via a spacer group as defined above, more preferably via a divalent, linear or branched, aliphatic C1-C18, preferably C1-C12, more preferably C1-C6, saturated or unsaturated, more preferably still C2 or C3, hydrocarbon radical 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, most particularly the diethylamino- or dimethylamino- group. R may be as defined above.

[0054] In some embodiments, the functionalized diene elastomer comprises at least one group comprising the Si-OR function, the group being represented by the formula (Ia):

[0055] (*— ) a If (OR)bR'cX

[0056] (the) in which:

[0057] - * — represents the bond to an elastomer chain;

[0058] - R' represents a substituted or unsubstituted C1-C10, or even C1-Cs, alkyl group, preferably a C1-C4 alkyl group, more preferably methyl or ethyl;

[0059] - R represents, independently of one another, a hydrogen atom or a substituted or unsubstituted C1-C10, or even C1-C8, alkyl group, preferably a C1-C4 alkyl group, more preferably methyl or ethyl;

[0060] - X represents another function (function different from the Si-OR function), the other function being able to be chosen from the group consisting of primary amines, secondary amines, tertiary amines, cyclic amines, isocyanates, imines, cyano, thiols, carboxylates, epoxides, primary phosphines, secondary phosphines and tertiary phosphines, the other function being able to 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-C1s, more preferably in C1-C12, more preferably in C1-Ce;

[0061] - a is 1 or 2, b is 1 or 2, and c is 0, or 1, provided that a+b+c =3.

[0062] In other words, the elastomer comprises at least one silicon atom substituted by at least one -OR group, with R as previously described, the substituted silicon atom corresponding to formula (Ia).

[0063] According to a variant in formula (la), a = 2, b=1 and c=0.

[0064] According to a variant, X is an amine function, preferably a primary or secondary amine, directly linked to the silicon atom itself directly integrated into the elastomer chain.

[0065] According to another variant, X is an amine function, preferably a primary or 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, linear or branched, aliphatic C1-C18, preferably C1-C12, more preferably C1-C6, saturated or unsaturated hydrocarbon radical, 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 X in formula (Ia), may be an amine function as described above, preferably a primary or secondary amine, linked to the silicon atom via a divalent, linear or branched, aliphatic C1-C6, preferably C2 or C3 hydrocarbon radical.Preferably, X is diethylamine or dimethylamine, preferentially linked to the silicon atom via a divalent, linear or branched, aliphatic C1-C6, more preferentially C2 or C3 hydrocarbon radical.

[0066] In some embodiments, the functionalized diene elastomer comprises at least one group of formula (Ia) in which:

[0067] * — represents the bond to an elastomeric chain; the radical R' represents an unsubstituted C1-C4 alkyl group;

[0068] R represents, independently of one another, a hydrogen atom or a C1-C4 alkyl group;

[0069] X represents a primary or secondary amine function, linked to the silicon atom via a linear or branched divalent hydrocarbon radical, aliphatic in C1-C6; a is 1 or 2, b is 1 or 2, and c is 0 or 1, provided that a+b+c =3.

[0070] In some embodiments, the functionalized diene elastomer comprises at least one group of formula (Ia) in which:

[0071] (*— ) a If (OR)bR'cX

[0072] (the) in which:

[0073] - * — represents the bond to an elastomer chain;

[0074] - c is equal to 0;

[0075] - R is as described above;

[0076] - X is as described above;

[0077] - a is worth 2 and b is worth 1.

[0078] 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 carrying a group of formula (Ia) in which X, R', R, a, b, and c are as defined above.The functionalized diene elastomers comprising a Si-OR function in the middle of the chain, in particular a group of formula (Ia), more preferably, the copolymers of styrene and butadiene comprising a group of formula (Ia), are mainly obtained by functionalization of a living elastomer resulting from an anionic polymerization by 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 silicon atom, 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 is obtained, the composition of which depends on the conditions of the modification reaction and in particular on the proportion of reactive sites of the functionalizing agent relative to the number of living elastomer chains. This mixture comprises species functionalized at the chain end, coupled, star-shaped and / or non-functionalized.

[0079] 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 a Si-OR function, very particularly a group of formula (Ia), linked to the two branches of the diene elastomer via the silicon atom. More particularly still, the diene elastomer functionalized in the middle of the chain represents at least 55% by weight of the functionalized diene elastomer.

[0080] Suitable functionalizing or coupling agents are trialkoxysilane and dialkoxyalkylsilane compounds substituted by a group comprising another function linked directly or via a spacer group to the silicon atom, the function and the spacer group being as defined above.More particularly, mention may be made, as functionalizing agent, 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 C1-C6, saturated or unsaturated, more particularly still in C2 or C3. Advantageously, the functionalizing agent is chosen from (N,N-dialkylaminoalkyl)trialkoxysilanes. More particularly, the functionalizing agent is 3-(N,N-dimethylaminopropyl)trimethoxysilane.

[0081] The functionalized diene elastomers comprising a Si-OR function in the middle of the chain, in particular a group of formula (Ia), more preferably the copolymers of styrene and butadiene can be prepared according to methods known to those skilled in the art, for example as described in WO2009 / 133068 or in WO2017001683A1.

[0082] In certain embodiments, when the functionalized diene elastomer comprises a Si-OR function at the chain end, the functionalized diene elastomer may comprise, at the chain end, a silanol function or a group represented by the formula (Ib):

[0083] -(If Ri R2-O-) m H

[0084] (I b) in which

[0085] - m represents an integer with a value ranging from 3 to 8, preferably 3;

[0086] - R1 and R2, identical or different, represent an alkyl group of 1 to 10 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms.

[0087] The chain end-functionalized diene elastomer is preferably a styrene-based and butadiene-based copolymer, more preferably a styrene-butadiene copolymer.

[0088] Functionalized diene elastomers comprising at the chain end a silanol function or a group of formula (Ib) can be prepared according to methods known to those skilled in the art, for example as described in EP0778311.

[0089] More particularly, such functionalized elastomers may be prepared according to a process consisting, after an anionic polymerization step, in functionalizing the living elastomer with a functionalizing agent of cyclic polysiloxane type provided that the reaction medium does not allow the polymerization of the cyclopolysiloxane. Cyclic polysiloxanes that may be mentioned include those corresponding to the formula: with m representing an integer with a value ranging from 3 to 8, preferably 3, R1 and R2, identical or different, represent an alkyl group of 1 to 10 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms. Among these compounds, mention may be made of hexamethylcyclotrisiloxane.

[0090] 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 formula (Ia) as defined above.

[0091] 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 (Ia) as defined above.

[0092] Thus, the functionalized elastomer can advantageously be used in a blend (mixture) with one or more other diene elastomer(s) different from the functionalized elastomer, preferably with one or more other non-functionalized diene elastomer(s). In the case of a blend, it is understood that the sum of the different elastomers used is equal to 100 pce.

[0093] 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), butadienes 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 pce of a functionalized diene elastomer as described above, more preferably from 50 to 100 pce of a functionalized diene elastomer comprising at least one group comprising the Si-OR function, the group being represented by formula (Ia) as defined above.

[0094] More preferably, the elastomeric composition useful in the context of the present invention comprises from 70 to 100 pce of a functionalized diene elastomer as described above, more preferably from 70 to 100 pce of a functionalized diene elastomer comprising at least one group comprising the Si-OR function, the group being represented by formula (Ia) as defined above.

[0095] In certain embodiments, the elastomeric composition useful in the context of the present invention 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 (Ia) as defined above.

[0096] Reinforcing charge

[0097] The elastomeric composition useful in the context of the present invention comprises a reinforcing filler, the reinforcing filler comprising at least one pyrolysis carbon black. In addition to the pyrolysis carbon black, the reinforcing filler may comprise one or more other reinforcing fillers.

[0098] Advantageously, the specific combination of at least one pyrolysis carbon black with at least one functionalized diene elastomer as defined above, in particular an elastomer functionalized in the middle of the chain, more particularly a diene elastomer functionalized in the middle of the chain by a Si-OR function, very particularly a group of formula (Ia) as defined above, makes it possible to obtain elastomeric compositions having iso-rigidity with the compositions of the prior art, in particular an improvement in rolling resistance.

[0099] The term "reinforcing filler" means any type of filler known for its ability to reinforce an elastomeric composition which can be used in particular for the manufacture of tires, for example organic fillers such as virgin carbon black or pyrolysis carbon black, or inorganic fillers such as silica or alumina.

[0100] In addition to the pyrolysis carbon black, the elastomeric composition may therefore also comprise at least one second reinforcing filler different from the pyrolysis carbon black, this second reinforcing filler being chosen from the group consisting of silicas, aluminas and virgin carbon blacks.

[0101] A person skilled in the art will be able to adapt the total rate of reinforcing filler, including the rate of pyrolysis carbon black, according to the relevant use of the elastomeric composition.

[0102] In certain embodiments, the level of reinforcing filler in the elastomeric composition useful in the context of the invention is within a range from 25 to 85 phr, preferably from 35 to 75 phr.

[0103] Preferably, the pyrolysis 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 filler.

[0104] Thus, preferably, the level of reinforcing filler in the elastomeric composition useful in the context of the invention is within a range from 25 to 85 phr, the pyrolysis carbon black 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.

[0105] Thus, more preferably, the level of reinforcing filler in the elastomeric composition useful in the context of the invention comprising at least one pyrolysis carbon black is within a range from 35 to 75 phr, the pyrolysis carbon black representing more than 30% by weight, more preferably representing more than 50% by weight, even more preferably representing more than 70% by weight, more preferably representing more than 90% by weight, of the total weight of the reinforcing filler.

[0106] In some embodiments, the reinforcing filler is solely pyrolysis carbon black. In some embodiments, the elastomeric composition comprises from 25 to 85 phr, preferably from 35 to 75 phr, of reinforcing filler, the reinforcing filler being pyrolysis carbon black. It should then be understood that the elastomeric composition, in this particular embodiment, comprises pyrolysis carbon black as the only reinforcing fillers (the elastomeric composition therefore does not comprise inorganic reinforcing fillers and other organic reinforcing fillers).

[0107] The reinforcing fillers may be as described below.

[0108] Pyrolysis carbon black

[0109] The elastomeric composition useful in the context of the invention comprises as reinforcing filler at least one pyrolysis carbon black.

[0110] For the purposes of the present invention, the term "pyrolysis carbon black" means a carbon black resulting from a process for the pyrolysis of a material comprising at least one carbon polymer and a carbon black, hereinafter the material to be pyrolyzed, for example in the context of the recycling of such a material. The physical state in which the material to be pyrolyzed is present is indifferent, whether in the form of powder, granules, strips, or any other form, in the crosslinked or non-crosslinked state.

[0111] Preferably, the material to be pyrolyzed may be recovered from manufactured articles or products generated during their manufacture / production (such as by-products or scraps); these manufactured articles may be chosen from the group consisting of pneumatic tires, non-pneumatic tires, industrial conveyor belts, transmission belts, rubber seals, rubber hoses, shoe soles and windshield wipers. Even more preferably, the pyrolysis carbon black that can be used in the context of the present invention is a carbon black obtained from a pyrolysis process in which the material to be pyrolyzed is derived from manufactured articles chosen from the group consisting of pneumatic tires and non-pneumatic tires.

[0112] Pyrolysis in the context of the present invention means any type of thermal decomposition in the absence of oxygen and whose raw material is the material to be pyrolyzed as defined above. Pyrolysis carbon blacks are therefore distinguished from so-called industrial and / or ASTM grade carbon blacks, also called virgin carbon blacks, in that the carbon raw material used for pyrolysis is a material comprising at least one carbon polymer and a carbon black and not materials derived from petroleum fractions or from coal or from oils of natural origin.

[0113] The pyrolysis carbon blacks that can be used in the context of the present invention are distinguished from known carbon blacks such as industrial and / or ASTM grade carbon blacks, in particular so-called “furnace” carbon blacks, also referred to below as “virgin carbon blacks”, in particular by a higher ash content.

[0114] Preferably, the pyrolysis carbon black usable in the context of the present invention has an ash content ranging from 5% to 30% by weight, more preferably ranging from 8% to 25% by weight, even more preferably ranging from 10% to 22% by weight, relative to the total weight of the pyrolysis carbon black.

[0115] Preferably, the pyrolysis carbon black usable in the context of the present invention has a sulfur content greater than 2% by weight, preferably ranging from 2.5% to 5% by weight, relative to the total weight of the pyrolysis carbon black.

[0116] 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 ranging from 2.5% to 8% by weight, relative to the total weight of the pyrolysis carbon black.

[0117] Preferably, the pyrolysis carbon black usable in the context of the present invention has a specific surface area STSA measured according to the ASTM D 6556-2021 standard within a range from 20 to 200 m 2 / g, more preferably ranging from 30 to 90 m 2 / g.

[0118] Preferably, the pyrolysis carbon black usable in the context of the present invention has a void volume measured according to standard ASTM D7854 (2018) and at a pressure of 50 MPa within a range from 30 to 60 ml / l 00g, more preferably from 35 to 55 ml / l 00g.

[0119] The ash content is determined by calcination in platinum capsules in a muffle furnace at 825°C according to the following protocol. A capsule is previously identified before each series of measurements and is tared to the nearest 0.1 mg and the mass is noted PO. In the capsule, 5 g of pyrolysis carbon black sample is introduced and weighed precisely to the nearest 0.1 mg; this mass is noted P1. The capsule and its contents are pre-calcined using a Bunsen burner until fumes appear and the product ignites. Once the product has completely burned, the capsule and its contents are introduced into a muffle furnace heated to 825 C for 1 h. After 1 h, the capsule is removed from the furnace and immediately placed in a desiccator at room temperature. When the capsule and the ash have returned to room temperature, the capsule is weighed again to obtain the mass P2.Finally, it is possible to obtain the ash content (% ash) using the formula below: 100.

[0120] The zinc content in the pyrolysis carbon black is determined after calcination of the sample, then recovery of the ash in an acid medium and determination by ICP-AES (inductively coupled plasma atomic emission spectroscopy). The ash is obtained by carrying out the above protocol. Approximately 100 mg of ash (test sample) is taken and placed in a PFA (perfluoroalkoxy) tube for a HotBIock hot plate. 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid and 0.5 mL of 40% hydrofluoric acid are then added. The tube is closed with its cap and heated at 130 C for 2 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). The volume is topped up with ultrapure water to the mark.The solution obtained is diluted by 100, by taking 1 mL in a 100 mL PFTE flask, previously containing 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, 0.5 mL of 40% hydrofluoric acid and 2 g of boric acid. This diluted solution is then filtered through a 0.45 pm GHP syringe filter before being analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Before analyzing the diluted solution, at least 5 standards are analyzed by ICP-AES at zinc concentrations of 0, 0.5, 1, 2 and 5 mg / L. These standards were prepared in 100 mL volumetric flasks, by diluting a certified commercial solution to a zinc concentration of 1 g / L.

[0121] These volumetric flasks contain 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, 0.5 mL of 40% hydrofluoric acid and 2 g of boric acid. The standard solutions are analyzed by ICP-AES at a wavelength of ÀZn = 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 related to the concentration using the calibration line obtained previously. The concentration [c]ash in % by mass is thus obtained directly by the software, because the test portion and the volume have been previously recorded. The zinc concentration in pyrolysis black [c]black in mass % is obtained by the following equation: ashes

[0122] The determination of the sulfur content in pyrolysis carbon blacks is carried out by LECO furnace. LECO sulfur analyzers are designed to measure, in particular, the sulfur content in organic and / or inorganic materials by combustion and non-dispersive infrared detection. Before measuring the sulfur content on the sample, the boats are cleaned and the furnace calibrated. The LECO perimeter boats are previously cleaned: this involves analyzing the empty boat under the same conditions as the samples. The preparation of the calibration curve is done using a commercial standard called "BBOT" whose purity is greater than 99.99% and whose carbon (C), hydrogen (H), nitrogen (N), oxygen (O) and sulfur (S) content is guaranteed. This content is as follows: C%: 72.52; H% 6.09; N% 6.51; 0% 7.43 and S% 7.44. Approximately 10 ± 3, 20 ± 3 and 40 ± 3 mg of BBOT are weighed exactly in a pod.The standard / boat assembly is introduced into the combustion furnace, regulated at 1350°C under pure oxygen. The combination of the furnace temperature and the analysis flow rate causes the combustion of the sample and the release of sulfur and / or carbon in the form of SO2(g). After a time of 20 s, oxygen begins to flow through the "lance" to accelerate the combustion of difficult-to-burn materials. The sulfur and / or carbon, in the form of SC>2(g), are carried by an oxygen flow through the infrared detection cells. The instrument software plots a straight line connecting the mass of standard introduced and the observed response (area) on the detector. This gives a calibration straight line. After carefully cleaning the sampling equipment, approximately 80 ± 5 mg of pyrolysis carbon black is weighed and introduced into a LECO furnace boat.The observed SO2 peak area is related to the concentration using the calibration line. The instrument software then calculates the mass % of sulfur in the sample using the mass of the sample introduced into the basket.

[0123] 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”.

[0124] The elastomeric composition useful in the context of the invention may further comprise a carbon black different from pyrolysis carbon black, this carbon black also being called “virgin carbon black” because it is not produced from materials already comprising carbon black. Virgin carbon black is produced from materials derived from petroleum fractions or from coal or from oils of natural origin.

[0125] All carbon blacks are suitable as virgin carbon blacks, including carbon blacks conventionally used in tires or their treads, in particular industrial carbon blacks, more specifically so-called "furnace" carbon blacks.

[0126] Among the virgin carbon blacks, we will mention in particular the reinforcing virgin carbon blacks of the 100, 200, 300 series, or the 500, 600 or 700 series blacks (ASTM D-1765-2017 grades), such as for example blacks N115, N134, N234, N326, N330, N339, N347, N375, N550, N683, N772.

[0127] Virgin carbon blacks can be used in the isolated state, as commercially available, or in any other form, for example as a carrier for some of the rubber additives used. Virgin 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).

[0128] The elastomeric composition useful in the context of the invention may comprise a silica or an alumina (i.e. one or more silicas or aluminas) which are reinforcing inorganic fillers.

[0129] By "reinforcing inorganic filler" is meant here any inorganic or mineral filler, whatever its color and origin (natural or synthetic), also called "white" filler, "clear" filler or even "non-black" filler as opposed to carbon black, capable of reinforcing on its own, without any other means than an intermediate coupling agent, an elastomeric composition intended for the manufacture of tires. As is known, certain reinforcing inorganic fillers can be characterized in particular by the presence of hydroxyl groups (-OH) on their surface.

[0130] Suitable reinforcing inorganic fillers are, in particular, mineral fillers of the siliceous type, preferably silica (SiC>2) or of the aluminous type, in particular alumina (AI2O3). The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET specific surface area and a CTAB specific surface area, both of less than 450 m 2 / g, preferably within a range of 30 to 400 m 2 / g, especially from 60 to 300 m 2 / g.

[0131] Any type of precipitated silica may be used, in particular highly dispersible precipitated silicas (called "HDS" for "highly dispersible" or "highly dispersible silica"). These precipitated silicas, whether highly dispersible or not, are well known to those skilled in the art. Examples include the silicas described in applications WO03 / 016215-A1 and WO03 / 016387-A1. Among the commercial HDS silicas, it is possible to use in particular the silicas "Ultrasil ® 5000GR", "Ultrasil ® 7000GR" from the company Evonik, the silicas "Zeosil ® 1085GR", "Zeosil® 1115 MP", "Zeosil® 1165MP", "Zeosil® Premium 200MP", "Zeosil® HRS 1200 MP" from the company Solvay.As non-HDS silica, the following commercial silicas can be used: silicas “Ultrasil ® VN2GR”, “Ultrasil ® VN3GR” from Evonik, silica “Zeosil® 175GR” from Solvay, silicas “Hi-Sil EZ120G(-D)”, “Hi-Sil EZ160G(- D)”, “Hi-Sil EZ200G(-D)”, “Hi-Sil 243LD”, “Hi-Sil 210”, “Hi-Sil HDP 320G” from PPG.

[0132] The BET specific surface area of ​​silica is determined in a known manner by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" Vol. 60, page 309, February 1938, more precisely according to the French standard NF ISO 9277 of December 1996 (multipoint volumetric method (5 points) - gas: nitrogen - degassing: 1 hour at 160°C - relative pressure range p / po: 0.05 to 0.17). The CTAB specific surface area of ​​silica is determined according to the French standard NF T 45-007 of November 1987 (method B).

[0133] As other examples of inorganic fillers that can be used in elastomeric compositions, mention may also be made of mineral fillers of the aluminous type, in particular alumina (AI2O3), aluminum oxides, aluminum hydroxides, aluminosilicates, titanium oxides, silicon carbides or nitrides, all of the reinforcing type as described, for example, in applications WO99 / 28376-A2, WO00 / 73372-A1, WO02 / 053634-A1, W02004 / 003067-A1,

[0134] W02004 / 056915-A2, US6610261-B1 and US6747087-B2. Examples include the aluminas “Baikalox A125” or “CR125” (Baïkowski company), “APA-100RDX” (Condéa), “Aluminoxid C” (Evonik) or “AKP-G015” (Sumitomo Chemicals).

[0135] The physical state in which the reinforcing inorganic filler is presented is indifferent, whether in the form of powder, microbeads, granules, or even beads or any other suitable densified form. Of course, the term reinforcing inorganic filler also means mixtures of different reinforcing inorganic fillers, in particular silicas as described above.

[0136] Those skilled in the art will understand that, as a replacement for the reinforcing inorganic filler described above, a reinforcing filler of another nature could be used, provided that this reinforcing filler of another nature is covered with an inorganic layer such as silica, or else comprises functional sites on its surface, in particular hydroxyl sites, requiring the use of a coupling agent to establish the bond between this reinforcing filler and the diene elastomer.

[0137] To couple the reinforcing inorganic filler to the diene elastomer, it is possible to use, in a well-known manner, an at least bifunctional coupling agent (or bonding agent) intended to ensure a sufficient connection, of a chemical and / or physical nature, between the inorganic filler (surface of its particles) and the diene elastomer. In particular, at least bifunctional organosilanes or polyorganosiloxanes are used. By "bifunctional", we mean a compound having a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the diene elastomer.For example, such a bifunctional compound may comprise a first functional group comprising a silicon atom, said first functional group being capable of interacting with the hydroxyl groups of an inorganic filler and a second functional group comprising a sulfur atom, said second functional group being capable of interacting with the diene elastomer.

[0138] Preferably, the organosilanes are chosen from the group consisting of polysulfurized organosilanes (symmetrical or asymmetrical) such as bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated to TESPT, marketed under the name “Si69” by the company Evonik or bis-(triethoxysilylpropyl) disulfide, abbreviated to TESPD, marketed under the name “Si75” by the company Evonik, polyorganosiloxanes, mercaptosilanes, blocked mercaptosilanes, such as S-(3-(triethoxysilyl)propyl) octanethioate marketed by the company Momentive under the name “NXT Silane”. More preferably, the organosilane is a polysulfurized organosilane.

[0139] The skilled person can find examples of coupling agent in the following documents: WO 02 / 083782, WO 02 / 30939, WO 02 / 31041, WO 2007 / 061550, WO 2006 / 125532, WO 2006 / 125533, WO 2006 / 125534, US 6,849,754, WO 99 / 09036, WO 2006 / 023815, WO 2007 / 098080, WO 2010 / 072685 and WO 2008 / 055986.

[0140] The coupling agent content preferably represents from 0.5% to 15% by weight relative to the amount of reinforcing inorganic filler, preferably from 4% to 12%, more preferably from 6% to 10% by weight relative to the amount of reinforcing inorganic filler. Typically, the coupling agent level is less than 20 phr, preferably within a range from 6 to 17 phr, preferably from 8 to 15 phr. This level can easily be adjusted by a person skilled in the art according to the level of reinforcing inorganic filler used in the elastomeric composition.

[0141] The elastomeric composition may also contain, in addition to the coupling agents, coupling activators, agents for covering inorganic fillers or more generally processing aids capable, in a known manner, thanks to an improvement in the dispersion of the filler in the rubber matrix and a reduction in the viscosity of the compositions, of improving their processability in the raw state, these agents being, for example, hydrolyzable silanes such as alkylalkoxysilanes (in particular alkyltriethoxysilanes), polyols, polyethers (for example polyethylene glycols), primary, secondary or tertiary amines (for example trialkanol-amines), hydroxylated or hydrolyzable POS, for example α,co-dihydroxy-polyorganosiloxanes (in particular α,co-dihydroxy-polydimethylsiloxanes).

[0142] Other organic loads

[0143] The elastomeric composition useful in the context of the invention may comprise a reinforcing organic filler of functionalized polyvinyl type as described in applications WO2006 / 069792-A1, WO2006 / 069793-A1, WO2008 / 003434-A1 and WO2008 / 003435-A1. crosslinking

[0144] The elastomeric composition useful in the context of the invention comprises a crosslinking system.

[0145] The crosslinking system may 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.

[0146] Preferably, the crosslinking system is sulfur-based, in which case we speak of a vulcanization system.

[0147] The sulfur can be provided in any form, in particular in the form of molecular sulfur, or a sulfur-donating agent. At least one vulcanization accelerator is also preferably present, and, optionally, also preferably, various known vulcanization activators can be used such as zinc oxide, stearic acid or equivalent compound such as stearic acid salts and transition metal salts, guanidine derivatives (in particular diphenylguanidine), or even known vulcanization retarders.

[0148] Sulphur is used at a preferential rate ranging from 0.5 to 12 pce, in particular from 1 to 10 pce.

[0149] The vulcanization accelerator is used at a preferential rate in the range of 0.5 to 10 pce, more preferably 0.5 to 5.0 pce.

[0150] Any compound capable of acting as an accelerator for the vulcanization of diene elastomers in the presence of sulfur may be used as an accelerator, in particular accelerators of the thiazole type and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. Examples of such accelerators include, but are not limited to, the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated as "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-tert-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-tert-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds.

[0151] Common additives and implementing agents

[0152] 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, agents promoting green tack (i.e. tackifying agent), pro-oxidizing metal salts, protective agents such as anti-ozone waxes, chemical antiozonants, antioxidants, anti-fatigue agents, reinforcing resins (as described, for example, in application WO 02 / 10269).

[0153] Preferably, the level of plasticizing agent(s) in the elastomeric composition useful in the context of the invention is within a range from 0 to 20 pce, more preferably within a range from 0 to 10 pce.

[0154] Production of compositions

[0155] The elastomeric composition useful in the context of the invention is manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art:

[0156] - a first working phase or thermomechanical mixing (so-called "non-productive" phase), which can be carried out in a single thermomechanical step during which all the necessary constituents are introduced into a suitable mixer such as a conventional internal mixer (for example of the 'Banbury' type), in particular the functionalized diene elastomer, the reinforcing filler(s) including pyrolysis carbon black, 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 in one or more stages by thermomechanical mixing.The non-productive phase is carried out at high temperature, up to a maximum temperature in the range from 110°C to 200°C, for a duration generally in the range from 2 to 10 minutes; - a second phase of mechanical work (so-called "productive" phase), which is carried out in an external mixer such as a roller mixer, after cooling the mixture obtained during the first non-productive phase to a lower temperature, typically below 120°C, for example ranging from 40°C to 100°C. The crosslinking system is then incorporated, and everything is then mixed for a few minutes, for example from 5 to 15 min.

[0157] The final elastomeric composition thus obtained is then calendered, for example, in the form of a sheet or plate, in particular for characterization in the laboratory, or extruded in the form of a semi-finished (or profiled) rubber usable, for example, as a tread for a tire, in particular as a tread for a tire of a vehicle carrying heavy loads, in particular a heavy goods vehicle or a civil engineering vehicle.

[0158] The elastomeric composition can be either in the raw state (before crosslinking or vulcanization), or in the cured state (after crosslinking or vulcanization), can be a semi-finished product which can be used in a tire.

[0159] 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.

[0160] Rubber goods

[0161] Another subject of the present invention relates to a rubber article comprising at least one elastomeric composition as defined above.

[0162] The rubber article can be any type of article such as a hose, a pipe, a gasket, an O-ring, a transmission belt, an engine mount, an insulation for electric cables, a 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.

[0163] 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. This can be any type of rubber strip, such as treads, underlays, etc.

[0164] More preferably, the elastomeric composition as defined above useful in the context of the invention constitutes all or part of said semi-finished article.

[0165] Preferably, the semi-finished article for pneumatic tires or for non-pneumatic tires is a tread.

[0166] As is known, the tread of a pneumatic or non-pneumatic tire comprises a rolling surface intended to be in contact with the ground when the pneumatic or non-pneumatic tire rolls. The tread is provided with a sculpture comprising in particular sculpture elements or elementary blocks delimited by various grooves.

[0167] Advantageously, the elastomeric composition as defined above useful in the context of the invention is present in the tread of the pneumatic tire or 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.

[0168] The term "pneumatic tire" means a tire intended to form a cavity by cooperating with a support element, for example a rim, this cavity being capable of being pressurized to a pressure higher than atmospheric pressure.

[0169] In contrast, a "non-pneumatic tire" is a tire that supports the load of a vehicle by a means other than a pressurized inflation gas. Thus, a non-pneumatic tire is a toric body made of at least one polymeric material, intended to perform the function of a tire but without being subjected to inflation pressure. A non-pneumatic tire may be solid or hollow. A hollow non-pneumatic tire may contain air, but at atmospheric pressure, i.e. it does not have pneumatic rigidity 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.

[0170] The pneumatic or non-pneumatic tires are intended to equip in particular vehicles of all types. Preferably, the rubber article according to the invention is a semi-finished article for a pneumatic tire, preferably a tread, such as a tread in particular consisting in whole or in part of at least one elastomeric composition as defined above. Even more preferably, the semi-finished article above is a semi-finished article for an industrial vehicle such as heavy goods vehicles, vans, agricultural vehicles, buses, metros, civil engineering vehicles, airplanes and other handling vehicles.

[0171] More preferably still, 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. More preferably still, 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 method well known to those skilled in the art.

[0172] Preferably, the rubber article is a pneumatic or non-pneumatic tire whose tread is made up in whole or in part of at least one elastomeric composition according to the invention.

[0173] The following examples are given for illustrative purposes, but should in no way be considered as limiting the present invention.

[0174] EXAMPLES

[0175] Measurement method

[0176] 1.1 Analysis of the function of the elastomer

[0177] NMR analyses are carried out on a 500 MHz BRUKER spectrometer equipped with a 5 mm BBIz "broadband" probe. For the NMR experiment 1 Quantitative H, the sequence uses a 30° pulse and a 2-second repetition delay. Samples are solubilized in carbon disulfide (CS2). 100 pL of deuterated cyclohexane (CODI2) is added for the lock signal. The NMR spectrum 1 H allows the quantification of the (CHs)2Si function by integration of the characteristic signal of the SiCHs protons around 5 = 0 ppm. The NMR spectrum 2 D 1 H- 29If allows the nature of the function to be verified using the chemical shift values ​​of the silicon nuclei and protons in the vicinity of 2J (via 2 bonds).

[0178] 1.2 Analysis of the microstructure of the elastomer

[0179] Near infrared spectroscopy (NIR) 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 a multivariate calibration [Vilmin, F.; Dussap, C; Coste, N. Applied Spectroscopy 2006, 60, 619-29] carried out using standard elastomers of composition determined by NMR 13C. The styrene content and microstructure are then calculated from the NIR spectrum of an elastomer film approximately 730 pm thick. The spectrum acquisition is carried out in transmission mode 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 a Peltier-cooled InGaAs detector.

[0180] 1.3 Dynamic Properties

[0181] The dynamic properties are measured on a viscoanalyzer (Metravib VA4000), according to ASTM D 5992-96. The response of a sample of the vulcanized elastomeric composition (cylindrical specimens of 4 mm thickness and 400 mm) is recorded. 2 section), subjected to sinusoidal stress in alternating simple shear, at a frequency of 10 Hz, at a temperature of 60°C.

[0182] For the measurements of dynamic complex 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, the maximum value of tan(delta) observed, noted tan(delta)max, is indicated; as well as the modulus G* at 25% strain noted G*25% at 60°C.

[0183] The tan(delta)max value is representative of the hysteresis of the material and in this case of the rolling resistance: the lower the tan(delta)max value, the better the rolling resistance. The G*25% values ​​measured at 60°C are representative of the stiffness, i.e. the resistance to deformation: the higher the G*25% value at 60°C, the greater the stiffness of the material, and therefore the better the wear resistance.

[0184] All values ​​are given in base 100 relative to a given control.

[0185] 1.4 Tensile Tests

[0186] Tensile tests are used to determine yield stresses and breaking properties. Unless otherwise stated, they are carried out in accordance with French standard NF T 46-002 (1988).

[0187] Processing the tensile records allows the modulus curve to be plotted as a function of elongation. The modulus used here is the nominal (or apparent) secant modulus measured at first elongation, calculated by referring to the initial section of the specimen. The nominal secant modulus (or apparent stress, in MPa) at 300% elongation, denoted MSA300, is measured at first elongation.

[0188] All values ​​are given in base 100 relative to a given control. A value greater than 100 indicates a value greater than that of the control.

[0189] Preparation of the compositions:

[0190] The manufacture of elastomeric compositions is prepared as follows: the functionalized diene elastomer or the non-functionalized diene elastomer is introduced into an internal mixer, filled to 70% and with an initial tank temperature of 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 except for the vulcanization system. Thermomechanical work (non-productive phase) is then carried out in one step, which lasts a total of approximately 3 to 5 minutes, until a maximum drop temperature of 160°C is reached. The resulting mixture is recovered, cooled and then the vulcanization system (sulfur and sulfenamide type accelerator) is added to an external mixer (homo-finisher) at 30°C, mixing the whole thing (productive phase) for approximately 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.

[0191] The formulations of the prepared elastomeric compositions are described in Table 1 (components and content - unless otherwise indicated, the contents are expressed in pce).

[0192] The rubber properties of these compositions are measured after curing 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 cured state (1) Diene elastomer: SBR solution, not extended, not functional, with 24% by weight relative to the butadiene part of polybutadiene 1,2 units; 26.5% by weight relative to the total weight of the copolymer of styrene units and a Tg = -48°C;

[0193] (2) Diene elastomer: SBR solution, not extended, functionalized, by an amino-alkoxysilane function in the middle of the chain, with 24% by weight relative to the butadiene part of polybutadiene units 1, 2; 26.5% by weight relative to the total weight of the elastomer of styrene units and a Tg = -48°C; this copolymer was synthesized according to the process described in document W02009 / 133068;

[0194] (3) Conventional carbon black of grade N326 according to ASTM D-1765-2017 marketed by Cabot, whose ash content is less than 0.7% by weight relative to the total weight of the carbon black, the sulfur content is less than 1.2% by weight relative to the total weight of the carbon black, the zinc is in the state of impurity (of the order of ppm)

[0195] (4) Pyrolysis carbon black “P550” from Scandinavian Enviro Systems, the ash content of which is 18.5% by weight relative to the total weight of the pyrolysis carbon black, the sulfur content is 3% by weight relative to the total weight of the pyrolysis carbon black, the zinc content is 4.5% by weight relative to the total weight of the pyrolysis carbon black;

[0196] (5) 2,2,2-trimethyl-1,2-dihydroquinoline from Flexsys;

[0197] (6) N-1,3-dimethylbutyl-N-phenyl-para-phenylenediamine from Flexsys;

[0198] (7) N-cyclohexyl-2-benzothiazyl-sulfenamide from Flexsys.

[0199] The tests highlight an improvement in the stiffness / hysteresis / reinforcement compromise for the elastomeric compositions in accordance with the invention (A1 and A2) compared to elastomeric compositions not in accordance with the invention (C1, C2, C3 and C4).

[0200] From Table 1, it is noted that an increase in the pyrolysis carbon black content in an elastomeric composition comprising a non-functionalized elastomer within the meaning of the present invention (C3 vs. C2) so as to obtain a rigidity equivalent (value of G*25% at 60°C) to that of the control elastomeric composition (C1) is accompanied by an increase in hysteresis (tan(delta)max at 60°C), therefore a degradation in rolling resistance performance, and a reduction in reinforcement (MSA300).

[0201] Surprisingly, with equivalent rigidity, the elastomeric composition A2 in accordance with the invention comprising a functionalized diene elastomer within the meaning of the present invention, compared to the elastomeric composition C3 not in accordance with the invention, allows a better rigidity / hysteresis compromise to be obtained.

Claims

CLAIMS 1. Elastomeric composition based on: - at least one diene elastomer comprising, at the end of the chain or 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 pyrolysis carbon black; and - a crosslinking system.

2. Elastomeric composition according to claim 1, in which the Si-OR function is located in the middle of the chain of the diene elastomer.

3. Elastomeric composition according to claim 1 or 2, 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 group.

4. Elastomeric composition according to any one of claims 1 to 3 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 (Ia): (*— ) a If (OR)bR'cX (the) in which: - * — represents the bond to an elastomer chain; - R' represents a substituted or unsubstituted C1-C10, or even C1-Cs, alkyl group, preferably a C1-C4 alkyl group; - R represents, independently of one another, a hydrogen atom or a substituted or unsubstituted C1-C10, or even C1-C8, alkyl group, preferably a C1-C4 alkyl group; - X represents another function (function different from the Si-OR function), the other function being able to be chosen from the group consisting of primary amines, secondary amines, tertiary amines, cyclic amines, isocyanates, imines, cyano, thiols, carboxylates, epoxides, primary phosphines, secondary phosphines and tertiary phosphines, X being linked directly or via a spacer group to the silicon atom; - a is 1 or 2, b is 1 or 2, and c is 0 or 1, provided that a+b+c =3.

5. Elastomeric composition according to claim 4, in which in formula (la): - * — represents the bond to an elastomer chain; - R' represents an unsubstituted C1-C4 alkyl group; - R represents, independently of one another, a hydrogen atom or a C1-C4 alkyl group; - X represents a primary or secondary amine function, linked directly or via a spacer group to the silicon atom; - a is 1 or 2, b is 1 or 2, and c is 0 or 1, provided that a+b+c =3.

6. Elastomeric composition according to claim 4 or 5 in which the spacer group is an atom or a divalent hydrocarbon radical, linear or branched, aliphatic in C1-C18, preferably in C1-C12, more preferably in C1-C6, saturated or not, cyclic or not, or a divalent aromatic hydrocarbon radical in C6-C8.

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 pyrolysis carbon black has an ash content ranging from 5% to 30% by weight, preferably from 8% to 25% by weight, relative to the total weight of the pyrolysis carbon black.

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

10. Elastomeric composition according to any one of the preceding claims, in which the composition comprises from 25 to 85 phr, preferably from 35 to 75 phr, of reinforcing fillers.

11. Elastomeric composition according to any one of the preceding claims, in which the pyrolysis carbon black represents more than 30% by weight, more preferably represents more than 50% by weight, more preferably still represents more than 70% by weight, more preferably still represents more than 90% by weight of the total weight of the reinforcing filler.

12. Elastomeric composition according to any one of the preceding claims, in which the reinforcing filler further comprises at least one second reinforcing filler different from the pyrolysis carbon black, this second reinforcing filler being chosen from the group consisting of virgin carbon blacks, aluminas and silicas.

13. A rubber article comprising at least one elastomeric composition according to any one of claims 1 to 12, the article preferably being selected from the group consisting of hoses, pipes, seals, O-rings, transmission belts, engine mounts, insulators for electric cables, shoe soles, semi-finished articles for pneumatic tires, semi-finished articles for non-pneumatic tires, non-pneumatic tires and pneumatic tires.

14. Rubber article according to claim 13, characterized in that it is a semi-finished product for pneumatic tires, preferably in that it is a tread.

15. Rubber article according to claim 13, said article being a pneumatic or non-pneumatic tire whose tread is made in whole or in part of at least one elastomeric composition according to any one of claims 1 to 12.

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