FR3005468A1 - PNEUMATIC COMPRISING A COMPOSITION ESSENTIALLY FREE OF GUANIDIC DERIVATIVE AND COMPRISING A TRIAZINE COMPOUND AND A PRIMARY AMINE - Google Patents

Abstract

The invention therefore relates to a tire comprising a rubber composition based on at least one diene elastomer, a reinforcing filler comprising mainly silica, a vulcanization system comprising a triazine compound of general formula (Ia) or (Ib), and a primary amine of formula (II), said composition being essentially devoid of guanidine derivative.

Description

The invention relates to tires and more particularly to those whose composition comprises a particular triazine compound and a primary amine. Since fuel savings and the need to protect the environment have become a priority, it has been necessary to produce tires with reduced rolling resistance without penalizing the other properties of the tire. Manufacturers have developed tire compositions that make it possible to reduce this rolling resistance, in particular by introducing silica into the mixtures as a reinforcing filler.

Also, the Applicants have already described the use of a vulcanization system comprising a particular triazine compound, as described in the documents FR 2951167, FR 2951183 and FR 2974099.

Nevertheless, the manufacturers are still looking for solutions to further reduce the rolling resistance of the tires, while maintaining a raw processability compatible with the industrial implementation of these solutions and it is in this context that the plaintiffs have discovered in a surprising way that the introduction of a primary amine replacing the guanidine derivatives in a composition comprising a particular triazine derivative makes it possible to reduce the hysteresis of the diene rubber compositions comprising silica as the majority reinforcing filler. Moreover, this solution has many other advantages over the compositions of the prior art and in particular the use of a lower cost compound and improving the environmental footprint. Primary amines have already been used in tire compositions different from those of the invention and for other purposes than to reduce the hysteresis of the compositions. For example, JP 2000-017107 discloses the use of low molecular weight alkyl amines to improve the processability of a mixture of diene elastomer and silica in the presence of diphenylguanidine (DPG). Also, EP 2241592 discloses the use of a low level of alkylamine (0.25 phr) in a mixture comprising carbon black and predominantly natural rubber. Nevertheless, these primary amines have never been used as proposed by the Applicants to replace guanidine derivatives in diene elastomer mixtures comprising silica as a majority filler, with the advantages presented above. The invention therefore relates to a tire comprising a rubber composition based on at least one diene elastomer, a reinforcing filler comprising mainly silica and a vulcanization system comprising a triazine compound of formula (Ia) or (Ib): ## STR2 ## where Mn + represents a metallic or non-metallic cation, n represents an integer varying between 1 and 4, R1 and R2 independently represent H, a halogen. , a group chosen from alkoxy and (C1-C10) alkylthio groups, or a C1-C20 hydrocarbon group selected from linear, branched or cyclic alkyl groups, aralkyl groups, alkylaryl groups and aryl groups, and optionally interrupted; by one or more heteroatoms, R1 being able to form a ring with R2, -A is selected from - -H, - a group S x N R'2 10 mn + / n Where -3 R'1 is identical to R1, R '2 is identical to R2, x is an integer greater than or equal to 1, preferably less than or equal to 10, more preferably less than or equal to 8 and most preferably less than or equal to 6; - an SR Y 3 group in which R 3 represents a C 1 -C 18 hydrocarbon-based group optionally interrupted by one or more heteroatoms, preferably a CR'3R4R5 group, where R'3, R4 and R5 independently represent a C1-C17 group optionally interrupted by one or more heteroatoms, y is an integer greater than or equal to 1, preferably less than or equal to 10, more preferably less than or equal to 8 and very preferably less than or equal to 6, - a group where R6 is a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms, - a group where R7 is a hydrocarbon-based group. C1-C18, optionally interrupted by one or more heteroatoms, - a group Y Y 0 'where Y is a C1-C18 hydrocarbon chain, optionally interrupted ue or substituted with one or more heteroatoms; R8 is a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms, - a group - 4 - R9 -01qi 0 where X is a C1-C18 hydrocarbon chain, optionally interrupted or substituted by one or more heteroatoms; R9 and R10 independently represent a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms, and - a group R11, where R11 is H or a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms a group NH - R12 where R12 represents a linear or branched C1-C25 alkyl group, optionally interrupted by one or more heteroatoms, optionally substituted by one or more C3-C10 cyclic alkyl groups or R6-O12 aryls, or R12 represents a cyclic alkyl group of Ca-Cio, optionally interrupted by one or more heteroatoms, optionally substituted with one or more linear, branched or cyclic C 1 -C 25 alkyl groups or aryl groups at 06-012, optionally interrupted by one or more heteroatoms, composition further comprising a primary amine of formula (II): R-NH2 (II) wherein R represents a linear hydrocarbon group e or branched comprising from 8 to 24 carbon atoms, said composition being devoid or comprising less than 0.5 phr of guanidine derivative.

Preferably, the invention relates to a tire as defined above wherein said composition comprises a triazine compound of general formula (Ia) or (Ib), characterized in that R1 and R2 independently represent a hydrogen atom or a phenyl group and in a preferred embodiment, R1 represents a hydrogen and R2 represents a phenyl group. According to a first preferred embodiment, the invention relates to a tire as defined above in which the group A is chosen from - the group S x NN R'2 - the group S -RY 3 - the group OR 9 0 - the group R11 where x, R'1, R'2, y, R3, X, R9, R10 and R11 are such than previously defined. Also preferably, the invention relates to a tire as defined above in which the groups R3 and R6 to R11 are independently selected from linear, branched or cyclic alkyl groups, aryl groups, aralkyl groups and alkylaryl groups. Preferably, the invention relates to a tire as defined above in which the X and Y groups are independently selected from linear, branched or cyclic alkylene groups, arylene groups and alkylarylene groups. Also preferably, the invention relates to a tire as defined above wherein Mn + is a metal cation selected from Zn2 +, Cu2 +, Na +, K + and Li. Alternatively and preferably also, Mn + is a non-metallic cation.

According to a second, more preferred embodiment, the invention relates to a tire as defined above in which A is a group - 6 - NH - R12 Where R12 represents a linear or branched C1-C25 alkyl group, optionally interrupted by one or more heteroatoms, optionally substituted with one or more C 3 -C 10 cyclic alkyl groups or R 6-012 aryls, or R 12 represents a C 3 -C 10 cyclic alkyl group, optionally interrupted by one or more heteroatoms, optionally substituted by one or more linear, branched or cyclic C1-C25 or aryl groups at 06-012, optionally interrupted by one or more heteroatoms. Preferentially, R12 represents a cyclohexyl group or a tert-butyl group.

Preferably, the invention relates to a tire as defined above in which the triazine compound represents from 0.1 to 10 phr, preferably from 0.1 to 7 phr, preferably from 0.2 to 7 phr, preferably still 0.5 to 7 phr, more preferably 0.5 to 5 phr (parts by weight per cent diene elastomer).

Preferably, the invention relates to a tire as defined above, in which the composition comprising the primary amine contains less than 0.45 phr of guanidine derivative, and preferably less than 0.4 phr.

Preferably also, the invention relates to a tire as defined above, in which the primary amine content is from 0.2 to 8 phr, preferably from more than 0.3 phr to 7 phr. More preferably, the primary amine level is from 0.5 to 5 phr, preferably from more than 0.6 phr to 4 phr.

More preferentially, the invention relates to a tire as defined above, in which the primary amine of formula (II) carries a radical R which represents a hydrocarbon group comprising from 10 to 22 carbon atoms. More preferably, R represents a hydrocarbon group comprising from 12 to 20 carbon atoms and preferably from 14 to 20 carbon atoms. Even more preferentially, the primary amine of formula (II) carries a radical R which represents a linear hydrocarbon. Preferably, the group R represents an alkyl group or an alkenyl group. Preferably, the invention relates to a tire as defined above, in which the silica content is from 30 to 150 phr. Also preferably, the invention relates to a tire as defined above, wherein the reinforcing filler comprises carbon black, in a minority. Preferably, the carbon black content is from 0.5 to 50 phr.

More preferably, the invention relates to a tire as defined above, in which the diene elastomer is chosen from the group consisting of polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers and copolymers. of isoprene (such as butadiene-styrene copolymers, isoprene-butadiene copolymers, isoprene-styrene copolymers or isoprene-butadiene-styrene copolymers) and mixtures of these elastomers. According to a preferred embodiment, the invention relates to a tire as defined above, in which the diene elastomer is predominantly composed of non-isoprene diene elastomer. Preferably, the invention relates to a tire as defined above, in which the diene elastomer is composed of 100 phr of non-isoprene diene elastomer.

Preferably also, the invention relates to a tire as defined above, in which the non-isoprene diene elastomer is chosen from the group consisting of polybutadienes, butadiene copolymers, isoprene copolymers (such as copolymers of butadiene-styrene, isoprene-butadiene copolymers, isoprene-styrene copolymers or isoprene-butadiene-styrene copolymers) and mixtures of these elastomers. More preferably, the invention relates to a tire as defined above, wherein the composition further comprises a plasticizer, preferably selected from plasticizing resins, extension oils and mixtures thereof. Preferably, the invention relates to a tire as defined above, in which the level of plasticizer is from 5 to 100 phr.

Preferably, the invention relates to a tire as defined above, wherein the composition is further free of zinc or contains less than 0.5 phr, preferably less than 0.3 phr. Also preferably, the invention relates to a tire as defined above, further comprising a coupling agent.

Preferably, the invention relates to a tire as defined above in which the coupling agent is a hydroxysilane polysulfide corresponding to the general formula (IV): (HO), R (3a) Si - R '- Sx -R '- Si R (3b) (OH) b (IV) in which: the radicals R, which are identical or different, are hydrocarbon groups preferably comprising from 1 to 15 carbon atoms; the radicals R ', which are identical or different, are divalent linking groups preferably comprising from 1 to 18 carbon atoms; a and b, identical or different, are 1 or 2; - X is a number greater than or equal to 2. More preferably, the invention relates to a tire as defined above in which the coupling agent is a mono-hydroxysilane in which a and b are equal to 1. More preferably again, the invention relates to a tire as defined above in which the radicals R are chosen from linear or branched C 1 -C 6 alkyls, C 5 -C 8 cycloalkyls or a phenyl radical; the radicals R 'are chosen from C1-C18 alkylenes or omega-06 arylenes. More particularly, the radicals R are chosen from C 1 -C 6 alkyls and R 'radicals from C 1 -C 10 alkylenes. Very preferably, the invention relates to a tire as defined above in which the hydroxysilane is a monohydroxysilane polysulfide of formula (V): ## STR2 ## in which the radicals R are C1-C3 alkyls, preferably methyl; the R 'radicals of the C1-C4 alkylenes, preferably methylene, ethylene or propylene; X is greater than or equal to 2. More particularly, the hydroxysilane is a bis (propyldimethylsilanol) polysulfide of particular formula (Va): ## STR1 ## Preferably, the invention relates to a tire such as defined above, wherein the composition comprising the triazine compound of formula (Ia) or (Ib) and the primary amine of formula (II) is the composition of a tire layer selected from the group consisting of all or part of tread, all or part of the tire belt and their combinations.

Preferably, the invention relates to a tire as defined above, in which the composition comprising the triazine compound of formula (Ia) or (Ib) and the primary amine of formula (II) is that of all or part of the tread. The tire according to the invention may comprise the composition described above in one or more of its different layers, such as, for example, the tread, the plies of the tire belt, the carcass ply or any other layer. For the purposes of the present application, the tire tread designates the rubber layer in contact with the ground, wholly (that is to say throughout its thickness) or a part of the latter (including the underlayer ), especially when it is composed of several layers. Preferably, the invention relates to a tire as defined above in which the composition comprising the triazine compound of formula (Ia) or (Ib) and the primary amine of formula (II) is the composition of a tire layer. selected from the group consisting of all or part of the tread, all or part of the tire belt and combinations thereof. Preferably, the invention relates to a tire as defined above in which the specified composition is that of all or part of the tread. Preferably, the tire according to the invention will be chosen from tires intended to equip a two-wheeled vehicle, a passenger vehicle, or a so-called "heavy vehicle" (that is to say, metro, bus , off-highway vehicles, road transport vehicles such as trucks, tractors, trailers), or aircraft, civil engineering, agrarian, or handling equipment. 1- Constituents of the Composition The rubber compositions according to the invention are based on the following constituents: at least one diene elastomer, a reinforcing filler mainly comprising silica, a vulcanization system comprising a triazine compound of general formula (la) or (Ib), and a primary amine of formula (II), said composition being devoid of or comprising less than 0.5 phr of guanidine derivative. In the formulas that precede and follow, the arrow () designates the point of attachment of groups A to the sulfur atom of formula (Ia) or (Ib). By the term "composition based on" is meant a composition comprising the mixture and / or the reaction product in situ of the various basic constituents used, some of these constituents being able to react and / or being intended to react with one another, at least partially, during the various phases of manufacture of the composition, or during subsequent firing, modifying the composition as it was initially prepared. Thus, the compositions as implemented for the invention may be different in the uncrosslinked state and in the crosslinked state.

In the present description, unless expressly indicated otherwise, all the percentages (%) indicated are percentages by mass. On the other hand, any range of values designated by the expression "between a and h" represents the range of values from more than a to less than b (i.e. terminals a and b excluded) while any range of values designated by the expression "from a to h" means the range from a to b (i.e., including the strict limits a and b). 1-1 Diene Elastomer The compositions may contain a single diene elastomer or a mixture of several diene elastomers.

By elastomer (or "rubber", the two terms being considered synonymous) of the "diene" type, it will be recalled here that it is to be understood in known manner that one or more elastomers derived from at least a part (ie, a homopolymer or copolymer) of diene monomers (monomers bearing two carbon-carbon double bonds, conjugated or otherwise). The 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% (mol%); Thus, diene elastomers such as butyl rubbers or copolymers of dienes and alpha-olefins of the EPDM type do not fall within the above definition and may in particular be described as "essentially saturated" diene elastomers ( low or very low diene origin, always less than 15%). In the category of "essentially unsaturated" diene elastomers, the term "highly unsaturated" diene elastomer is particularly understood to mean a diene elastomer having a content of units of diene origin (conjugated dienes) which is greater than 50%.

These definitions being given, the term "diene elastomer" can be understood more particularly to be used in the compositions according to the invention: (a) - any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms; (b) - any copolymer obtained by copolymerization of one or more conjugated dienes with each other or with one or more vinyl aromatic compounds having from 8 to 20 carbon atoms; (c) - a ternary copolymer obtained by copolymerization of ethylene, an α-olefin having 3 to 6 carbon atoms with a non-conjugated diene monomer having from 6 to 12 carbon atoms, for example elastomers obtained from ethylene, propylene with a non-conjugated diene monomer of the aforementioned type such as in particular 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene; (d) - a copolymer of isobutene and isoprene (butyl rubber), as well as the halogenated versions, in particular chlorinated or brominated, of this type of copolymer.

Although it applies to any type of diene elastomer, those skilled in the art of pneumatics will understand that the present invention is preferably carried out with essentially unsaturated diene elastomers, in particular of the type (a) or (b) above.

By way of conjugated dienes 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di (C 1 -C 5 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, aryl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene. Suitable vinylaromatic compounds are, for example, styrene, ortho-, meta-, para-methylstyrene, the "vinyl-toluene" commercial mixture, para-tertiarybutylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene. The copolymers may contain between 99% and 20% by weight of diene units and between 1% and 80% by weight of vinylaromatic units. The elastomers may have any microstructure which is a function of the polymerization conditions used, in particular the presence or absence of a modifying and / or randomizing agent and the amounts of modifying and / or randomizing agent used. The elastomers can be for example block, statistical, sequence, microsequential, and be prepared in dispersion or in solution; they may be coupled and / or starred or functionalized with a coupling agent and / or starring or functionalization. For coupling with carbon black, there may be mentioned, for example, functional groups comprising a C-Sn bond or amine functional groups such as aminobenzophenone for example; for coupling to a reinforcing inorganic filler such as silica, mention may be made, for example, of silanol or polysiloxane functional groups having a silanol end (as described, for example, in FR 2,740,778, US 6,013,718 and VVO 2008/141702), alkoxysilane groups (as described for example in FR 2,765,882 or US 5,977,238), carboxylic groups (as described for example in VVO 01/92402 or US 6,815,473, VVO 2004/096865 or US 2006/0089445 ) or polyether groups (as described for example in EP 1 127 909, US 6 503 973, VVO 2009/000750 and VVO 2009/000752). As other examples of functionalized elastomers, mention may also be made of elastomers (such as SBR, BR, NR or IR) of the epoxidized type.

These functionalized elastomers may be used in a blend with each other or with unfunctionalized elastomers. For example, a silanol or polysiloxane-functionalized elastomer having a silanol end, in admixture with a coupled and / or tin-starred elastomer (described in VVO 11/042507), may be used, the latter representing a 5 to 50%, for example 25 to 50%.

Suitable polybutadienes and in particular those having a content (mol%) in units -1.2 of between 4% and 80% or those having a content (mol%) of cis-1,4 greater than 80%, polyisoprenes, copolymers of butadiene-styrene and in particular those having a Tg (glass transition temperature (Tg, measured according to ASTM D3418) of between 0 ° C. and -70 ° C. and more particularly between -10 ° C. and -60 ° C., a styrene content of between 5% and 60% by weight and more particularly between 20% and 50%, a content (mol%) in -1,2 bonds of the butadiene part of between 4% and 75%, a content ( mol%) in trans-1,4 bonds of between 10% and 80%, butadiene-isoprene copolymers and in particular those having an isoprene content of between 5% and 90% by weight and a Tg of -40 ° C. to At -80 ° C., the isoprene-styrene copolymers and in particular those having a styrene content of between 5% and 50% by weight and a Tg between -5 ° C and -60 ° C. In the case of butadiene-styrene-isoprene copolymers are especially suitable those having a styrene content of between 5% and 50% by weight and more particularly between 10% and 40%, a isoprene content between 15% and 60% by weight and more particularly between 20% and 50%, a butadiene content of between 5% and 50% by weight and more particularly between 20% and 40%, a content (% molar) in units -1,2 of the butadiene part of between 4% and 85%, a content (mol%) in trans-1,4 units of the butadiene part of between 6% and 80%, a content (mol% ) in units -1.2 plus -3.4 of the isoprene part of between 5% and 70% and a content (mol%) in trans units of -1.4 of the isoprenic part of between 10% and 50%, and more generally any butadiene-styrene-isoprene copolymer having a Tg between -20 ° C and -70 ° C. In summary, the diene elastomer of the composition is preferably chosen from the group of highly unsaturated diene elastomers consisting of polybutadienes (abbreviated "BR"), synthetic polyisoprenes (IR), natural rubber (NR), copolymers butadiene, isoprene copolymers and mixtures of these elastomers. Such copolymers are more preferably selected from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR), isoprene-copolymers of butadiene-styrene (SBIR), butadiene-acrylonitrile copolymers (NBR), butadiene-styrene-acrylonitrile copolymers (NSBR) or a mixture of two or more of these compounds. According to one particular embodiment, the composition comprises from 50 to 100 phr of an SBR elastomer, whether it be an emulsion-prepared SBR ("ESBR") or a SBR prepared in solution ("SSBR "). According to another particular embodiment, the diene elastomer is a blend (mixture) SBR / BR.

According to other possible embodiments, the diene elastomer is a SBR / NR (or SBR / IR), BR / NR (or BR / IR) or SBR / BR / NR (or SBR / BR / IR) blend. ). In the case of an SBR elastomer (ESBR or SSBR), an SBR having an average styrene content, for example between 20% and 35% by weight, or a high styrene content, for example 35 to 35% by weight, is used in particular. 45%, a vinyl content of the butadiene part of between 15% and 70%, a content (mol%) of trans-1,4 bonds of between 15% and 75% and a Tg of between -10 ° C. and -55 ° C; such an SBR can be advantageously used in admixture with a BR preferably having more than 90% (mol%) of cis-1,4 bonds. According to another particular embodiment, the diene elastomer is a predominantly isoprene elastomer (that is to say whose mass fraction of isoprene elastomer is the largest, compared to the mass fraction of other elastomers). By "isoprene elastomer" is meant in known manner a homopolymer or copolymer of isoprene, in other words a diene elastomer selected from the group consisting of natural rubber (NR) which can be plasticized or peptized, the polyisoprenes of synthesis (IR), the various isoprene copolymers and the mixtures of these elastomers. Among the isoprene copolymers, mention will in particular be made of copolymers of isobutene-isoprene (butyl rubber - IIR), isoprene-styrene (SIR), isoprene-butadiene (BIR) or isoprene-butadiene-styrene (SBIR). This isoprene elastomer is preferably natural rubber or synthetic cis-1,4 polyisoprene; of these synthetic polyisoprenes, polyisoprenes having a content (mol%) of cis-1,4 bonds greater than 90%, more preferably still greater than 98%, are preferably used. Preferably, according to another embodiment, the rubber composition comprises predominantly (i.e. with the highest mass ratio) a non-isoprene diene elastomer. By "non-isoprene diene elastomer" is meant within the meaning of the present application an elastomer derived at least in part (ie, a homopolymer or a copolymer) from monomers dienes (monomers bearing two carbon-carbon double bonds) other than isoprene. Thus, the non-isoprenic diene elastomers within the meaning of the present definition also include copolymers comprising isoprene as a comonomer. Natural rubber and isoprenic homopolymers (ie consisting of isoprene functionalized monomers or not) are excluded from the present definition. According to this preferred embodiment, all the elastomers mentioned above with the exception of natural rubber and polyisoprenes are suitable as non-isoprene diene elastomer. In particular, it is possible to use non-isoprenic diene elastomers preferably chosen from the group of highly unsaturated diene elastomers consisting of polybutadienes (abbreviated to "BR"), butadiene copolymers, isoprene copolymers and mixtures of these elastomers. Such copolymers are more preferably selected from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR) and isoprene-copolymers. butadiene-styrene (SBIR). Still according to this preferred embodiment, it will be understood that, in the case of elastomer cutting, the total content of so-called "non-isoprenic" elastomers must be greater than the total content of the elastomers chosen from the group consisting of natural rubber and polyisoprenes. synthesis and mixtures thereof. Preferably, according to this embodiment, the level of non-isoprene diene elastomer is more than 50 phr, more preferably at least 60 phr, more preferably at least 70 phr, more preferably at least 80 phr. pce and very preferably at least 90 phr. In particular according to this embodiment, the level of non-isoprene diene elastomer is very preferably 100 phr.

According to another preferred embodiment of the invention, the rubber composition comprises a blend of one (or more) diene elastomers referred to as "high Tg" having a Tg of between -70 ° C. and 0 ° C. and one (or more) diene elastomers known as "low Tg" between -110 ° C and -80 ° C, more preferably between -105 ° C and -90 ° C. The high Tg elastomer is preferably selected from the group consisting of S-SBR, E-SBR, natural rubber, synthetic polyisoprenes (having a content (mol%) of cis-1,4 linkages preferably greater than 95%), BIR, SIR, SBIR, and mixtures of these elastomers. The low Tg elastomer preferably comprises butadiene units at a level (mol%) of at least 70%; it consists preferably of a polybutadiene (BR) having a content (mol%) of cis-1,4 chains greater than 90%. According to another particular embodiment of the invention, the rubber composition comprises, for example, between 30 and 90 phr, in particular between 40 and 90 phr, of a high Tg elastomer in a blend with a low Tg elastomer. Another particular embodiment of the invention, the diene elastomer of the composition according to the invention comprises a blend of a BR (as low elastomer Tg) having a rate (% molar) of cis-chains. 1.4 greater than 90%, with one or more S-SBR or E-SBR (as elastomer (s) high Tg). 1-2 Reinforcing filler The tire according to the invention comprises a composition which contains, predominantly, silica as a reinforcing filler. By majority reinforcing filler is meant that which has the highest rate among the reinforcing fillers present in the composition. In particular, the term "majority reinforcing filler" means any reinforcing filler which represents at least 50% by weight of the reinforcing fillers present, preferably more than 50% and more preferably more than 60%.

The physical state under which the reinforcing filler is present is indifferent, whether in the form of powder, microbeads, granules, beads or any other suitable densified form.

The volume fraction of reinforcing filler in the rubber composition is defined as the ratio of the volume of the reinforcing filler to the volume of all the constituents of the composition, it being understood that the volume of all the constituents is calculated in adding the volume of each of the constituents of the composition. The volume fraction of reinforcing filler in a composition is therefore defined as the ratio of the volume of the reinforcing filler to the sum of the volumes of each of the constituents of the composition, typically this volume fraction is between 10% and 30%. preferably between 15% and 25%. In a preferentially equivalent manner, the total reinforcing filler content (carbon black and / or reinforcing inorganic filler such as silica) is 30 to 200 phr, more preferably 30 to 150 phr, and very preferably 50 to 100 phr. 135 pce. According to a preferred embodiment of the invention, a reinforcing filler comprising from 30 to 150 phr of silica, more preferably from 50 to 130 phr of silica, and optionally carbon black, is used; the carbon black, when present, is used in combination with silica more preferably at a level of 0.5 to 50 phr, more preferably from 1 to 20 phr (especially between 1 and 10 phr). The composition may contain a type of silica or a blend of several silicas. The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or fumed silica having a BET surface and a CTAB specific surface both less than 450 m 2 / g, preferably from 30 to 400 m 2 / boy Wut. As highly dispersible precipitated silicas (referred to as "HDS"), mention may be made, for example, of the "Ultrasil 7000" and "Ultrasil 7005" silicas of Degussa, the "Zeosil" silicas 1165MP, 1135MP and 1115MP of Rhodia, "Hi-Sil EZ150G" silica from PPG, the "Zeopol" silicas 8715, 8745 and 8755 from Huber, processed precipitated silicas such as, for example, the "aluminum doped" silicas described in the EP-A application; A-0735088 or silicas with high specific surface area as described in application VVO 03/16837.

The silica preferably has a BET surface area of between 45 and 400 m 2 / g, more preferably between 60 and 300 m 2 / g. These compositions may optionally also contain, in addition to the coupling agents, coupling activators, inorganic charge-covering agents or, more generally, processing aid agents that are capable in a known manner, by means of 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 use in the green state, these agents being for example hydrolysable silanes such as alkylalkoxysilanes, polyols, fatty acids, polyethers, primary, secondary or tertiary amines, hydroxyl or hydrolyzable polyorganosiloxanes. Polysulfide silanes, called "symmetrical" or "asymmetrical" silanes according to their particular structure, are used, for example, as described for example in the applications W003 / 002648 (or US 2005/016651) and W003 / 002649 (or US 2005 / 016650).

In particular, polysulphide silanes known as "symmetrical" silanes having the following general formula (III) are suitable, but not limited to: (III) Z - A - Sx - A - Z, in which: - x is an integer of 2 to 8 (preferably 2 to 5); A is a divalent hydrocarbon radical (preferably C 1 -C 18 alkylene groups or C 8 -C 12 arylene groups, more particularly C 1 -C 10 alkylenes, especially C 1 -C 4 alkylenes, in particular propylene); Z corresponds to one of the following formulas: ## STR2 ## in which: the radicals R 1, substituted or unsubstituted, identical or different from each other, represent a C 1 -C 18 alkyl, C 5 -C 18 cycloalkyl or C 8 -C 18 aryl (preferably C 1 -C 8 alkyl, cyclohexyl or phenyl groups, especially C 1 -C 4 alkyl groups, more particularly methyl and / or 'ethyl). the radicals R2, substituted or unsubstituted, which are identical to or different from one another, represent a C1-C18 alkoxyl or a C5-C18 cycloalkoxyl group (preferably a group chosen from C1-C8 alkoxyls and C5-C8 cycloalkoxyls, plus still more preferably a group chosen from C1-C4 alkoxyls, in particular methoxyl and ethoxyl). In the case of a mixture of polysulfide alkoxysilanes corresponding to formula (III) above, in particular common commercially available mixtures, the average value of "x" is a fractional number preferably between 2 and 5, more preferably close to 4. But the invention can also be advantageously used for example with disulfide alkoxysilanes (x = 2). As examples of polysulphide silanes, mention may be made more particularly of bis (C 1 -C 4) alkoxyl (C 1 -C 4) alkylsilyl-C 1 -C 4 alkyl (especially disulfide, trisulphide or tetrasulfide) polysulphides. )), such as, for example, bis (3-trimethoxysilylpropyl) or bis (3-triethoxysilylpropyl) polysulfides. Among these compounds, bis (3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT, of formula [(C2H50) 3Si (CH2) 3S1 or bis (triethoxysilylpropyl) disulfide, abbreviated TESPD, of formula (C2H50) 3Si (CH2) 3SK. Mention may also be made, by way of preferred examples, of polysulfides (in particular disulphides, trisulphides or tetrasulfides) of bis- (monoalkoxyl (C1-C4) -dialkyl (C1-C4) silylpropyl), more particularly bis-monoethoxydimethylsilylpropyl tetrasulfide, as described above. in the patent application VVO 02/083782 (or US 2004/132880). As coupling agent other than polysulfide alkoxysilane, mention may also be made of bifunctional POS (polyorganosiloxanes) or hydroxysilane polysulfides (R2 = OH in formula III above) as described in the patent applications VVO 02/30939 (or US Pat. No. 6,774,255) and VVO 02/31041 (or US 2004/051210), or also silanes or POS bearing azo-dicarbonyl functional groups, as described, for example, in patent applications VVO 2006/125532, VVO 2006/125533, VVO 2006/125534. In particular, and preferably, the coupling agent may be a hydroxysilane polysulfide (as described in the documents cited above) corresponding to the general formula (IV): (HO), R (3a) Si - R '- SR' - Si R (3b) (OH) b (IV) in which: the radicals R, which are identical or different, are hydrocarbon groups preferably comprising from 1 to 15 carbon atoms; the radicals R ', which are identical or different, are divalent linking groups preferably comprising from 1 to 18 carbon atoms; a and b, identical or different, are equal to 1 or 2; x is a number greater than or equal to 2.

The radicals R, identical or different, linear or branched, preferably containing from 1 to 15 carbon atoms, are more preferably chosen from alkyls, cycloalkyls or aryls, in particular from C 1 -C 6 alkyls, cycloalkyls in 05-08 and the phenyl radical. Among these radicals, mention may be made, for example, of those selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl and neopentyl. , n-hexyl, 2-ethylhexyl, n-octyl, isooctyl, cyclopentyl, cyclohexyl, 2-methylcyclohexyl, phenyl, toluyl, benzyl. More preferably still, the R radicals, which may be identical or different, are C1-C3 alkyls (ie methyl, ethyl, n-propyl, isopropyl), most preferably chosen from methyl and ethyl. The radicals R ', identical or different, substituted or unsubstituted, are preferably hydrocarbon radicals, saturated or unsaturated, containing from 1 to 18 carbon atoms, these radicals R' being able to be interrupted within the hydrocarbon chain by at least one heteroatom such as O, S or N. Suitable in particular are C1-C18 alkylene groups or 06012 arylene groups, more particularly C1-C10 alkylenes, especially C1-C4 alkylenes, in particular those chosen from methylene and ethylene. and propylene.

Preferably, in the hydroxysilane polysulfides corresponding to the general formula (IV), the hydroxysilane is a monohydroxysilane, that is to say that a and b are equal to 1. Also preferably, the radicals R are chosen among linear or branched C 1 -C 6 alkyls, C 5 -C 8 cycloalkyls or a phenyl radical; the radicals R 'are chosen from C1-C18 alkylenes or arylenes at 06-012, and more particularly, the radicals R are chosen from C1-C6 alkyls and R' radicals from C1-C10 alkylenes. Thus, very preferably, the hydroxysilane is a polysulfide of mono-hydroxysilane of formula (V): ## STR2 ## in which the R radicals are C 1 -C 3 alkyls, preferably the methyl; the R 'radicals of the C1-C4 alkylenes, preferably methylene, ethylene or propylene; X is greater than or equal to 2. More particularly, the hydroxysilane may be a bis (propyldimethylsilanol) polysulfide of particular formula (Va): ## STR2 ## This product of formula (## STR2 ## Va) corresponds to product D in the previously cited document VVO 02/31041 (or US 2004/051210). In the rubber compositions according to the invention, the content of coupling agent is preferably between 2 and 15 phr, more preferably between 3 and 13 and even more preferably between 5 and 10 phr.

In addition to the silica, it is possible to use any type of reinforcing filler known for its ability to reinforce a rubber composition that can be used for the manufacture of tires, for example an organic filler such as carbon black, a reinforcing inorganic filler such as alumina, or a blend of these two types of filler. Carbon blacks are suitable for all carbon blacks, especially so-called pneumatic grade blacks. Among these, the reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades), for example the N115, N134, N234, N326, N330, N339, N347 or N375 blacks, or even targeted applications, blacks of higher series (eg N660, N683, N772). The carbon blacks could for example already be incorporated into an isoprene elastomer in the form of a masterbatch (see for example applications VVO 97/36724 or VVO 99/16600).

As examples of organic fillers other than carbon blacks, mention may be made of the organic functionalized polyvinyl fillers as described in applications VVO-A-2006/069792, VVO-A-2006/069793, VVO-A-2008/003434 and VVO-A2008 / 003435.

The person skilled in the art will understand that, as the equivalent filler of the silica described in this paragraph, it would be possible to use a reinforcing filler of another nature, in particular an organic one, since this reinforcing filler would be covered with a silica layer, or would comprise on its surface functional sites, especially hydroxyl, requiring the use of a coupling agent to establish the bond between the filler and the elastomer. 1-3 Vulcanization system The vulcanization system itself is based on sulfur (or a sulfur-donor agent) and a primary vulcanization accelerator. To this basic vulcanization system are added, incorporated during the first non-productive phase and / or during the production phase as described later, various known secondary accelerators or vulcanization activators such as zinc oxide. stearic acid or equivalent compounds, guanidine derivatives (in particular diphenylguanidine).

Sulfur is used at a preferential level of between 0.5 and 10 phr, more preferably between 0.5 and 5 phr, in particular between 0.5 and 3 phr, when the composition of the invention is intended, according to a method. of the invention to constitute a tire tread. According to the invention, the vulcanization system comprises, as primary vulcanization accelerator, one or more triazine compounds chosen from compounds of formula (Ia) or (Ib): ## STR2 ## where Mn + represents a metallic or non-metallic cation, n represents an integer varying between 1 and 4, 25 mn + / n (1b); R1 and R2 independently represent H, a halogen, a chosen group; by the alkoxy and (C1-C10) alkylthio groups, or a C1-C25 hydrocarbon group selected from linear, branched or cyclic alkyl groups, aralkyl groups, alkylaryl groups and aryl groups, and optionally interrupted by one or more heteroatoms, R1 being able to form a ring with R2, A is chosen from - -H, - a group S,... N N1 N NR, R'2 where R'1 is identical to R1, R'2 is identical at R2, x is an integer greater than or equal to 1, preferentially less than or equal to 10, more preferential preferably less than or equal to 6, a group - "- S -RY 3 where R 3 represents a C 1 -C 18 hydrocarbon-based group optionally interrupted by one or more heteroatoms, preferably a CR'3R4R5 group where R'3, R4 and R5 independently represent a C1-C17 group optionally interrupted by one or more heteroatoms, y is an integer greater than or equal to 1, preferentially less than or equal to 10, more preferably less than or equal to 8 and very preferably less than or equal to 6, - a group where R6 is a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms, - a group where R7 is a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms, - a group O where Y is a C1-C18 hydrocarbon-based chain, optionally interrupted OR substituted with one or more heteroatoms; R8 is a C1-018 hydrocarbon group, optionally interrupted by one or more heteroatoms, - a group OR 90 where X is a C1-C18 hydrocarbon chain, optionally interrupted or substituted by one or more heteroatoms; R9 and R10 independently represent a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms, - a group R11, where R11 is H or a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms, and an NH-R12 group where R12 represents a linear or branched C1-C25 alkyl group optionally interrupted by one or more heteroatoms, optionally substituted with one or more C3-C10 cyclic alkyl groups or with 6-O12 aryls, or R12 represents a cyclic alkyl group of Ca-C10, optionally interrupted by one or more heteroatoms, optionally substituted by one or more linear, branched or cyclic C 1 -C 25 alkyl groups or aryl groups at 06-012, optionally interrupted by one or more heteroatoms; . By cyclic alkyl group is meant an alkyl group consisting of one or more rings. By group or hydrocarbon chain (e) interrupted by one or more heteroatoms is meant a group or chain comprising one or more heteroatoms, each heteroatom being between two carbon atoms of said group or said chain, or between an atom carbon of said group or said chain and another heteroatom of said group or said chain or between two other hetero atoms of said group or said chain.

The heteroatom (s) may be a nitrogen, sulfur or oxygen atom. According to a first embodiment, R1 and R2 independently represent H or a phenyl group.

According to a second embodiment, R2 represents a phenyl group and R1 represents H. The compound or compounds of formula (Ia) or (Ib) are advantageously chosen from compounds whose group A is chosen from - the group R'2 - the group Y 3 - the group OR 9 0 - the group R 11 - 26 - where x, R '1, R' 2, y, R 3, X, R 9, R 10 and R 11 are as defined above. Preferably, the groups R3 and R6 to R11 may be chosen independently from linear, branched or cyclic alkyl groups, aryl groups, aralkyl groups and alkylaryl groups, subject to any conditions previously explained for each of these groups. Also preferably, the groups R'3, R4 and R5 may be independently selected from linear, branched or cyclic alkyl groups, aryl groups, aralkyl groups and alkylaryl groups.

Preferably, the groups X and Y may be independently selected from linear, branched or cyclic alkylene groups, arylene groups and alkylarylene groups. Preferably, the Mn + cation may be a metal cation chosen from Zn2 +, Cu2 +, Na +, K + and Li +. Preferably also, the cation Mn + may be a non-metallic cation such as an ammonium ion, for example the ion NMe4 +, NH4 + or H3NMe +. According to a particular embodiment, R'3, R4 and R5 represent a methyl group.

According to a particular embodiment, R6 represents a C1-C4 alkyl, more preferably a C1-C3 alkyl and very preferably a methyl group or an ethyl group.

According to a particular embodiment, R7 represents a C1-C4 alkyl, more preferably a C1-C3 alkyl and very preferably a methyl group or an ethyl group, or R7 represents an aralkyl group such as for example a benzyl group.

According to a particular embodiment, Y represents a C1-C4 alkylene, more preferably a C1-C3 alkylene and very preferably a propylene group or an ethylene group and R8 represents a C1-C4 alkyl, more preferably a C1-C3 alkyl and very preferably a methyl group or an ethyl group.

According to a particular embodiment, X represents a C1-C4 alkylene, more preferably a C1-C3 alkylene and very preferably a methylene group or an ethylene group, and R9 and R10 independently represent a C1-alkyl. -04, more preferably a C1-C3 alkyl and very preferably a methyl group or an ethyl group. According to one particular embodiment, R 11 represents H. As compounds of formula (Ia) or (Ib) particular, there may be mentioned the following compounds: ## STR1 ## Also preferably, A is a radical of the formula ## STR2 ## wherein R is a radical of the formula ## STR2 ## which R12 represents a linear or branched C1-C25 alkyl group, optionally interrupted by one or more heteroatoms, optionally substituted by one or more C3-C103 cyclic alkyl groups or C6-C12 aryl groups, or a C3-C12 cyclic alkyl group; -010, optionally interrupted by one or more heteroatoms, optionally substituted with one or more linear, branched or cyclic C 1 -C 0 or aryl groups at 06-012, optionally interrupted by one or more heteroatoms, more preferably R 12 represents a cyclohexyl group or a tertbutyl group. R12 is cyclohexyl and R1 is H, R2 is phenyl. Thus, a preferred compound of formula (Ia) is that wherein R1 is H, R2 is phenyl and R12 is cyclohexyl. In this case, the triazine compound of formula (la) is 3 - [(cyclohexylamino) thio] -5-phenyl-1,2,4-triazine. According to another preferred embodiment, R12 represents a tert-butyl group. Thus, another preferred compound (Ia) is that wherein R 1 is hydrogen, R 2 is phenyl and R 12 is tert-butyl. One such compound is 3 - [(t-butylamino) thio] -5-phenyl-1,2,4-triazine. The synthesis of compounds of formula (Ia) or (Ib) is described in documents FR 2951167, FR 2951183 and FR 2974099 with regard to these methods of preparation. The compound of formula (Ia) or (Ib), that is to say the compound (s) of formula (Ia) or (Ib), if there are several, generally represent from 0.1 to 10 phr, preferably from 0.1 to 7 phr, preferably from 0.2 to 7 phr, more preferably from 0.5 to 7 phr, more preferably from 0.5 to 5 phr. The compounds of formula (Ia) or (Ib) may advantageously replace all or part of the accelerator compounds conventionally used. The vulcanization system of the composition according to the invention may also comprise one or more additional accelerators, for example compounds of the thiuram family, zinc dithiocarbamate derivatives, sulfenamides, guanidines (provided they contain less than 0.5 phr) or thiophosphates. In particular, any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur, in particular thiazole type accelerators and their derivatives, thiuram type accelerators, zinc dithiocarbamates, may be used in particular. These accelerators are more preferably selected from the group consisting of 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide (abbreviated as "CBS"), N, N-dicyclohexyl-2-benzothiazyl sulphenamide (abbreviated "DCBS"), N-tert-butyl-2-benzothiazyl sulphenamide (abbreviated "TBBS"), N-tert-butyl-2-benzothiazyl sulphenimide (abbreviated "TBSI"), zinc dibenzyldithiocarbamate (in abbreviated "ZBEC") and mixtures of these compounds. Preferably, a primary accelerator of the sulfenamide type is used. On the other hand, in the tires according to the invention, the composition comprising the triazine compound of formula (Ia) or (Ib) and the primary amine of formula (II) necessary for the purposes of the invention is devoid of guanidine derivative or contains less than 0.5 phr. Preferably, the composition is either totally devoid of such compounds, or it contains less than 0.45 phr, preferably less than 0.4 phr, more preferably less than 0.3 phr, preferably less than 0, 2 phr and very preferably less than 0.1 phr. The term "guanidine derivative" is understood to mean the organic compounds bearing as their main function a guanidine function, such as those known in tire compositions, in particular as vulcanization accelerators, for example diphenylguanidine (DPG) or diorthotolylguanidine (DOTG). According to a preferred embodiment, in the tire according to the invention, the composition comprising the triazine compound of formula (Ia) or (Ib) and the primary amine of formula (II) necessary for the needs of the invention is also free of zinc or contains less than 0.5 phr, preferably less than 0.3 phr, more preferably less than 0.2 phr and most preferably less than 0.1 phr. 1-4 primary amine. guanidine derivatives mentioned above, the tire according to the invention comprises a primary amine of formula (II): R-NH 2 (II) in which R represents a linear or branched hydrocarbon group comprising from 8 to 24 carbon atoms. Preferentially, R represents a linear or branched hydrocarbon group comprising from 10 to 22 carbon atoms, more preferably from 12 to 20 carbon atoms and very preferably from 14 to 20 carbon atoms. Preferably, R represents a linear hydrocarbon group. For the purposes of the present invention, the term "hydrocarbon group" means a group comprising saturated or unsaturated carbon and hydrogen atoms, such as an alkyl or alkenyl group. Preferably, the hydrocarbon group comprises from 0 to 3 unsaturations, preferably 0, 1 or 2. Preferably, the hydrocarbon group is saturated, it is an alkyl group. Alternatively, and preferably also, this hydrocarbon group is unsaturated, it is therefore an alkenyl group.

Preferably, the primary amine as defined above may be chosen from linear alkylamines. Very preferably, it is hexadecylamine or octadecylamine, and especially octadecylamine. Octadecylamine (or stearylamine) is commercially available, for example in powder form from a supplier such as Aldrich. Preferably, the level of primary amine in the composition is within a range of from 0.2 to 8 phr, more preferably from 0.3 to 7 phr, preferably from more than 0.5 phr to 5 phr and more preferably from 0.6 to 4 phr.

It may be noted that the primary amine as defined below is introduced in the free base form, i.e. not forming a salt with a mineral or organic acid. 1-5 Other Possible Additives The rubber compositions according to the invention optionally also include all or part of the usual additives usually used in elastomer compositions intended in particular for the production of treads, such as, for example, pigments, such as anti-ozone waxes, chemical anti-ozonants, anti-oxidants, plasticizers such as those proposed below, anti-fatigue agents, reinforcing resins, acceptors (for example phenolic novolac resin) or methylene donors (eg HMT or H3M).

According to a preferred embodiment, the composition according to the invention further comprises a plasticizer. Preferably this plasticizer is a solid hydrocarbon resin (or plasticizing resin), an extender oil (or plasticizing oil), or a mixture of both.

When it is included in the composition, the level of total plasticizer is preferably greater than or equal to 5 phr, more preferably 5 to 100 phr, in particular 10 to 80 phr, for example 15 to 70 phr. According to a first preferred embodiment of the invention, the plasticizer is a liquid extension oil at 20 ° C, said to "low Tg", that is to say that by definition has a Tg lower than -20 ° C, preferably below -40 ° C. Any extender oil, whether aromatic or non-aromatic in nature known for its plasticizing properties vis-à-vis diene elastomers, is usable. At ambient temperature (20 ° C), these oils, more or less viscous, are liquids (that is to say, as a reminder, substances having the ability to eventually take the shape of their container), as opposed in particular to hydrocarbon plasticizing resins which are inherently solid at room temperature.

Particularly suitable are the extender oils selected from the group consisting of naphthenic oils (low or high viscosity, especially hydrogenated or non-hydrogenated), paraffinic oils, MES (Medium Extracted Solvates) oils, TDAE (Treated) oils. Distillate Aromatic Extracts), mineral oils, vegetable oils, ethers plasticizers, ester plasticizers, phosphate plasticizers, sulphonate plasticizers and mixtures of these compounds. For example, there may be mentioned those containing between 12 and 30 carbon atoms, for example trioctyl phosphate. By way of examples of non-aqueous and non-water-soluble ester plasticizers, mention may be made in particular of compounds selected from the group consisting of trimellitates, pyromellitates, phthalates, 1,2-cyclohexane dicarboxylates, adipates, azela- sebacates, glycerol triesters and mixtures of these compounds.

Among the triesters above, mention may be made in particular of glycerol triesters, preferably consisting mainly (for more than 50%, more preferably for more than 80% by weight) of an unsaturated fatty acid in O18, that is, that is to say chosen from the group consisting of oleic acid, linoleic acid, linolenic acid and mixtures of these acids. More preferably, whether of synthetic or natural origin (for example vegetable oils of sunflower or rapeseed), the fatty acid used is more than 50% by weight, more preferably still more than 80% by weight. % by weight of oleic acid. Such high oleic acid triesters (trioleates) are well known and have been described, for example, in application VVO 02/088238, as plasticizers in tire treads. Preferably, the extender oil content is between 2 and 50 phr, more preferably between 3 and 40 phr, more preferably between 5 and 35 phr.

According to another preferred embodiment of the invention, this plasticizer is a thermoplastic hydrocarbon resin whose Tg is greater than 0 ° C, preferably greater than 20 ° C. This resin is a solid at room temperature (23 ° C), as opposed to a liquid plasticizer such as an oil.

Preferably, the thermoplastic hydrocarbon plasticizing resin has at least one of the following characteristics: a Tg greater than 20 ° C, more preferably greater than 30 ° C; a number-average molecular mass (Mn) of between 400 and 2000 g / mol, more preferentially between 500 and 1500 g / mol; - a polymolecularity index (Ip) of less than 3, more preferably less than 2 (recall: lp = Mw / Mn with Mw weight average molecular weight). More preferably, this thermoplastic hydrocarbon plasticizing resin has all of the above preferred characteristics.

The macrostructure (Mw, Mn and lp) of the hydrocarbon resin is determined by steric exclusion chromatography (SEC): solvent tetrahydrofuran; temperature 35 ° C; concentration 1 g / I; flow rate 1 ml / min; filtered solution on 0.45 μm porosity filter before injection; Moore calibration with polystyrene standards; set of 3 "WATERS" columns in series ("STYRAGEL" HR4E, HR1 and HR0.5); differential refractometer detection ("WATERS 2410") and its associated operating software ("WATERS EMPOVVER"). The thermoplastic hydrocarbon resins may be aliphatic or aromatic or alternatively of the aliphatic / aromatic type, that is to say based on aliphatic and / or aromatic monomers. They may be natural or synthetic, whether based on petroleum or not (if so, also known as petroleum resins).

Suitable aromatic monomers are, for example, styrene, alpha-methylstyrene, ortho-, meta-, para-methylstyrene, vinyl-toluene, paratertiobutylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, any vinylaromatic monomer resulting from a Cg cut (or more generally from a Cg to C10 cut). Preferably, the vinylaromatic monomer is styrene or a vinylaromatic monomer derived from a Cg cut (or more generally from a C8 to C10 cut). Preferably, the vinylaromatic monomer is the minor monomer, expressed as a mole fraction, in the copolymer under consideration.

According to a particularly preferred embodiment, the plasticizing hydrocarbon resin is selected from the group consisting of homopolymer resins or copolymers of cyclopentadiene (abbreviated CPD) or dicyclopentadiene (abbreviated DCPD), terpene homopolymer or copolymer resins, terpene phenol homopolymer or copolymer resins, homopolymer or C5 cut copolymer resins, homopolymer or C9 cut copolymer resins, alpha-methyl-styrene homopolymer and copolymer resins, and blends - These resins can be used alone or in combination with a liquid plasticizer, for example a MES or TDAE oil. The term "terpene" here combines in a known manner the alpha-pinene, beta-pinene and limonene monomers; preferably, a limonene monomer is used which is present in a known manner in the form of three possible isomers: L-limonene (laevorotatory enantiomer), D-limonene (dextrorotatory enantiomer), or the dipentene, racemic of the dextrorotatory and levorotatory enantiomers. . Among the above-mentioned hydrocarbon plasticizing resins, there may be mentioned resins of homo- or copolymers of alphapinene, betapinene, dipentene or polylimonene.

The preferred resins above are well known to those skilled in the art and commercially available, for example sold with regard to: - polylimonene resins: by the company DRT under the name "Dercolyte L120" (Mn = 625 g / mol Mw = 1010 g / mol, Ip = 1.6, Tg = 72 ° C.) or by ARIZONA under the name "Sylvagum TR71250" (Mn = 630 g / mol, Mw = 950 g / mol, Ip = 1 5, Tg = 70 ° C); - 05 / vinylaromatic copolymer resins, in particular cut 05 / styrene or cut 05 / cut Cg: by Neville Chemical Company under the names "Super Nevtac 78", "Super Nevtac 85" or "Super Nevtac 99", by Goodyear Chemicals under "VVingtack Extra" denomination, by Kolon under the names "Hikorez T1095" and "Hikorez T1100", by Exxon under the names "Escorez 2101" and "Escorez 1273"; limonene / styrene copolymer resins: by DRT under the name "Dercolyte TS 105" from the company DRT, by ARIZONA Chemical Company under the names "ZT115LT" and "ZT5100". As examples of other preferred resins, mention may also be made of phenol-modified alpha-methyl-styrene resins. To characterize these phenol-modified resins, it is recalled that a so-called "hydroxyl number" index (measured according to ISO 4326 and expressed in mg KOH / g) is used in a known manner. The alpha-methylstyrene resins, in particular those modified phenol, are well known to those skilled in the art and commercially available, for example sold by Arizona Chemical under the names "Sylvares SA 100" (Mn = 660 g / mol; lp = 1.5, Tg = 53 ° C); "Sylvares SA 120" (Mn = 1030 g / mol, lp = 1.9, Tg = 64 ° C); "Sylvares 540" (Mn = 620 g / mol, lp = 1.3, Tg = 36 ° C, hydroxyl number = 56 mg KOH / g); "Silvares - 600" (Mn = 850 g / mol, Lp = 1.4, Tg = 50 ° C., hydroxyl number = 31 mg KOH / g). According to a particular embodiment of the invention, when it is included in the composition, the level of plasticizing hydrocarbon resin is between 5 and 50 phr, preferably between 7 and 40 phr, more preferably between 10 and 35 phr. Preferentially also, the content of plasticizing resin is between 5 and 20 phr, and more preferably between 5 and 15 phr. Of course, the compositions according to the invention can be used alone or in a blend (i.e., in a mixture) with any other rubber composition that can be used for the manufacture of tires. It goes without saying that the invention relates to the rubber compositions described above both in the so-called "raw" or uncrosslinked state (ie, before firing) in the so-called "cooked" or cross-linked state, or vulcanized ( ie, after crosslinking or vulcanization). II-Preparation of the rubber compositions The compositions are manufactured in appropriate mixers, using two successive preparation phases well known to those skilled in the art: a first phase of work or thermomechanical mixing (sometimes referred to as "non-phase" phase). at high temperature, up to a maximum temperature of between 110 ° C and 190 ° C, preferably between 130 ° C and 180 ° C, followed by a second mechanical working phase (sometimes referred to as a "productive" phase). ") at a lower temperature, typically below 110 ° C, for example between 60 ° C and 100 ° C, finishing phase during which is incorporated the crosslinking system or vulcanization; such phases have been described for example in the applications EP-A-0501227, EP-A0735088, EP-A-0810258, W000 / 05300 or W000 / 05301.

The first (non-productive) phase is preferably carried out in several thermomechanical steps. In a first step, the elastomers and the reinforcing fillers (and optionally the coupling agents and / or other ingredients) are introduced into a suitable mixer such as a conventional internal mixer at a temperature of between 20.degree. ° C and 100 ° C and preferably between 25 ° C and 100 ° C.

After a few minutes, preferably 0.5 to 2 min and a rise in temperature at 90 ° C to 100 ° C, the other ingredients (i.e., those remaining if all not started) are added at once or in parts, except for the vulcanization system during mixing ranging from 20 seconds to a few minutes. The total mixing time, in this non-productive phase, is preferably between 2 and 10 minutes at a temperature of less than or equal to 180 ° C, and preferably less than or equal to 170 ° C. After cooling the mixture thus obtained, the vulcanization system is then incorporated at low temperature (typically below 100 ° C.), generally in an external mixer such as a roller mixer; the whole is then mixed (productive phase) for a few minutes, for example between 5 and 15 min. The final composition thus obtained is then calendered, for example in the form of a sheet or a plate, in particular for a characterization in the laboratory, or extruded, to form for example a rubber profile used for the manufacture of semi-finished products. finished in order to obtain products such as sidewalls, carcass ply, crown plies (or tire belt), tread, bead filler, tread underlayer or other layers of elastomers, preferentially the rolling. These products can then be used for the manufacture of tires, according to the techniques known to those skilled in the art. The vulcanization (or cooking) is conducted in a known manner at a temperature generally between 130 ° C and 200 ° C, under pressure, for a sufficient time which can vary for example between 5 and 90 min depending in particular on the cooking temperature , the vulcanization system adopted, the kinetics of vulcanization of the composition in question or the size of the tire. The following examples illustrate the invention without limiting it.

III-Examples of embodiment of the invention III-1 Preparation of the examples In the examples which follow, the rubber compositions were produced as described previously. III-2 Characterization of the Examples In the examples, the rubber compositions are characterized before and / or after cooking as indicated below. Mooney viscosity or Mooney plasticity (before firing): An oscillating consistometer is used as described in the French standard NF T 43005 (1991). The Mooney plasticity measurement is carried out according to the following principle: the raw composition (i.e., before firing) is molded in a cylindrical chamber heated to 100 ° C. After one minute of preheating, the rotor rotates within the test tube at 2 revolutions / minute and the useful torque is measured to maintain this movement after 4 minutes of rotation. The Mooney plasticity (ML 1 + 4) is expressed in "Mooney unit" (UM, with 1 UM = 0.83 Newton.meter). For more readability the results will be indicated in base 100, the value 100 being attributed to the witness. A result less than 100 indicating a decrease in the value concerned, and vice versa, a result greater than 100, will indicate an increase in the value concerned. Dynamic properties (after firing): The dynamic properties G * and tan (δ) max are measured on a viscoanalyzer (Metravib V A4000), according to the ASTM D 5992 - 96 standard. The response of a sample of vulcanized composition is recorded. (cylindrical test specimen, 4 mm thick and 400 mm2 cross section), subjected to sinusoidal stress in alternating single shear, at a frequency of 10 Hz, under normal temperature conditions (23 ° C) according to ASTM D 1349 - 99. A peak-to-peak deformation amplitude scan is performed from 0.1 to 50% (forward cycle), then from 50% to 1% (return cycle). The results exploited are the complex dynamic shear modulus (G *) and the loss factor (tan Ô). For the return cycle, the maximum value of tan observed (tan (8), x) and the complex modulus difference (3.G *) between the values at 0.1% and 50% are indicated. deformation (Payne effect). For more readability the results will be indicated in base 100, the value 100 being attributed to the witness. A result less than 100 indicating a decrease in the value concerned, and vice versa, a result greater than 100, will indicate an increase in the value concerned.35 - 38 - III-3 Examples III-3-1 Example I This example is intended to to compare the different rubber properties of control compositions with compositions according to the invention, that is to say comprising a diene elastomer, a reinforcing filler predominantly comprising silica, a vulcanization system comprising a triazine compound of formula general (la), and a primary amine of formula (II), the compositions being devoid or containing less than 0.5 phr of guanidine derivative. The compound of formula (Ia) used in the example is that in which R1 is H, R2 is phenyl and R12 is cyclohexyl, that is 3- [(cyclohexylamino) thio] -5. -phény1-1,2,4-triazine.

In particular the compositions T-1 to T-2 and C-1 to C-4 were prepared and tested. The composition Ti does not comprise the triazine compound of formula (Ia) or the primary amine of formula (II). The composition T-2 varies with respect to the first control only by replacing the CBS with a triazine compound of formula (Ia) (in an isomolar amount), as shown in Table 1. The compositions C-1 to C- 4 are in accordance with the invention. Composition C-1 comprises the replacement of CBS with a triazine compound of formula (Ia) (in an isomolar amount) and the replacement of DPG with octadecylamine (in an isomolar amount) relative to control T-1. Composition C-2 illustrates an embodiment in which the composition is free of zinc. Composition C-3, for its part, is identical to composition C-1 in which a preferred coupling agent is used. The composition C-4, for its part, is identical to the composition C-3 in which the zinc oxide has been removed. The compositions are made with an introduction of all the components on an internal mixer, with the exception of the vulcanization system. The vulcanizing agents (sulfur and accelerator) are introduced on an external mixer at low temperature (the constituent rolls of the mixer being at about 30 ° C.). Table 2 below gives the properties measured before and after cooking. For a better understanding and comparison of the tests, the results are given in base 100, that is to say that the experimental value for the control is brought back to the value 100 then the values of the tests are given according to this base of 100 for the witness. Table 1 Composition T-1 T-2 C-1 C-2 C-3 C-4 SBR (1) 100 100 100 100 100 100 Carbon Black (2) 3 3 3 3 3 3 Silica (3) 110 110 110 110 110 110 Coupling agent 1 (4) 8.8 8.8 8.8 8.8 - - Coupling agent 2 (5) - - - - 6.5 6.5 Protective agents (6) 3.6 3.6 3.6 3.6 3.6 3.6 Plasticizing oil (7) 12 12 12 12 12 12 Plasticizing resin (8) 46 46 46 46 46 46 Guanidine derivative (9) 1.8 1.8 - - - - Octadecylamine - - 2,3 2,3 2,3 2,3 ZnO 1,2 1,2 1,2 - 1,2 - Stearic acid 2 2 2 2 2 2 Sulfur 1 1 1 1 1 1 CBS (10 ) 2,3 - - - - - Triazine compound (11) - 2,5 2,5 2,5 2,5 2,5 (1) SBR (Sn star) with 27% styrene and 24% pattern 1 , 2 of the butadiene part (Tg = -48 ° C) carrying a silanol function at the end of the elastomer chain (2) ASTM grade N234 (Cabot company) (3) "Zeosil 1165 MP" silica of the Rhodia type company "HDS" (4) coupling agent: TESPT ("5i69" from Evonik-Degussa) (5) Coupling agent: bis (propyldim) polysulfide thylsilanol) as described in the document VVO 02/31041 (or US 2004/051210) (6) N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine (Santoflex 6-PPD) of the company Flexsys and anti-ozone wax (7) Sunflower oil 85% by weight of oleic acid "Lubrirob Tod 1880" from Novance (8) Resin C5 / C9 "Escorez 1273" from Exxon (9) Diphenylguanidine (" Perkacit DPG from Flexsys) (10) N-cyclohexyl-2-benzothiazol sulfenamide ("Santocure CBS" from Flexsys) (11) 3 - [(cyclohexylamino) thio] -5-phenyl-1 , 2,4-triazine Table 2 Composition T-1 T-2 C-1 C-2 C-3 C-4 Mooney (base 100) 100 98 100 103 84 93 AG * (base 100) 100 139 91 90 100 82 Tan (O) max back (base 100) 100 103 89 92 105 100 Compared to the control compositions, it is noted that the compositions C-1 to C-4 have a reduced hysteresis, as attested by values of tan ( Ô) max and AG * diminished, and / or compromise hysteresis / processability bareback improved (lower Mooney value). 10

Claims (37)

REVENDICATIONS1. A tire comprising a rubber composition based on at least one diene elastomer, a reinforcing filler predominantly composed of silica, and a vulcanization system comprising a compound of the following formula (Ia) or (Ib): ## STR2 ## ) mn + / n (lb) where Mn + represents a metallic or non-metallic cation, n represents an integer varying between 1 and 4, R1 and R2 independently represent H, a halogen, a group chosen from alkoxy and (C1-C10) alkylthio, or a C1-C25 hydrocarbon group selected from linear, branched or cyclic alkyl groups, aralkyl groups, alkylaryl groups and aryl groups, and optionally interrupted by one or more heteroatoms, R1 being able to form a ring with R2, A is selected from - -H, - a group S x NN R'2 where R'1 is identical to R1, R'2 is identical to R2, x is an integer greater than or equal to 1, preferentially less than or equal to 10 , plus- 42 - prefer ntiellement less than or equal to 8 and very preferably less than or equal to 6, - a group S -RY 3 where R 3 represents a C 1 -C 18 hydrocarbon-based group optionally interrupted by one or more heteroatoms, preferably a CR'3R4R5 group, where R R 3 and R 5 independently represent a C 1 -C 17 group optionally interrupted by one or more heteroatoms, y is an integer greater than or equal to 1, preferentially less than or equal to 10, more preferably less than or equal to 8 and very preferably lower than or equal to 6, a group O where R6 is a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms, a group where R7 is a C1-C18 hydrocarbon group, optionally interrupted by a or more heteroatoms, a group where Y is a C1-C18 hydrocarbon chain, optionally interrupted or substituted by one or more heteroatoms; R 8 is a C 1 -C 18 hydrocarbon group, optionally interrupted by one or more heteroatoms, - a group OR 9 where X is a C 1 -C 18 hydrocarbon chain, optionally interrupted or substituted by one or more heteroatoms; R9 and R10 independently represent a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms, and - a group R11 where R11 is H or a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms, - a group NH - R12 Ot.i R12 represents a linear or branched C1-C25 alkyl group, optionally interrupted by one or more heteroatoms, optionally substituted with one or more C3-C10 cyclic alkyl groups or with 6-O12 aryls, or R12 represents a cyclic alkyl group of Ca-C10, optionally interrupted by one or more heteroatoms, optionally substituted by one or more linear, branched or cyclic C 1 -C 25 alkyl groups or aryl groups at 06-012, optionally interrupted by one or more heteroatoms; said composition further comprising a primary amine of formula (II): RN H2 (11) wherein R represents a linear hydrocarbon group wherein said composition is free or comprising less than 0.5 phr of guanidine derivative. 2. A tire according to claim 1, wherein said composition comprises a triazine compound of general formula (Ia) or (Ib) wherein R1 and R2 independently represent a hydrogen atom or a phenyl group. 3. A tire according to claim 2, characterized in that R1 represents a hydrogen and R2 represents a phenyl group. 4. A tire according to any one of the preceding claims, characterized in that the group A is chosen from - the group - 44 - S x NN R'2 - the group S -RY 3 - the group OR 9 0 - the group R11, / wherein x, R'1, R'2, y, R3, X, R9, R10 and R11 are as defined in claim 1. 5. A tire according to any one of the preceding claims, characterized in that the groups R3 and R6 to R11 are independently selected from linear, branched or cyclic alkyl groups, aryl groups, aralkyl groups and alkylaryl groups. Pneumatic tire according to any one of the preceding claims, characterized in that the X and Y groups are independently selected from linear, branched or cyclic alkylene groups, arylene groups and alkylarylene groups. 7. A tire according to any one of the preceding claims, characterized in that Mn + is a metal cation selected from Zn2 +, Cu2 +, Na +, K + and Li. 8. A tire according to any one of claims 1 to 6, characterized in that Mn + is a non-metallic cation. Pneumatic tire according to any one of claims 1 to 3, characterized in that A is a NH-R12 group where R12 is a linear or branched C1-C25 alkyl group optionally interrupted by one or more heteroatoms. , optionally substituted by one or more cyclic alkyl groups at 03-010 or aryls at 06-012, or else R12 represents a cyclic alkyl group at 03-010, optionally interrupted by one or more heteroatoms, optionally substituted by one or more alkyl groups linear, branched or cyclic Cl-025 or aryls at 06-012, optionally interrupted by one or more heteroatoms. 10. A tire according to claim 9 characterized in that R12 represents a cyclohexyl group or a tertbutyl group. 11. A tire according to any one of the preceding claims, characterized in that the triazine compound represents from 0.1 to 10 phr, preferably from 0.1 to 7 phr, preferably from 0.2 to 7 phr, more preferably from 0.5 to 7 phr, more preferably from 0.5 to 5 phr (parts by weight per cent of diene elastomer). 12. A tire according to any one of the preceding claims, wherein said composition contains less than 0.45 phr of guanidine derivative, and preferably less than 0.4 phr. 13. A tire according to any preceding claim wherein the primary amine level is 0.2 to 8 phr, preferably more than 0.3 phr to 7 phr. 14. A tire according to claim 13 wherein the primary amine level is 0.5 to 5 phr, preferably more than 0.6 phr to 4 phr. 15. A tire according to any one of the preceding claims wherein the primary amine of formula (II) bears a radical R which represents a hydrocarbon group comprising from 10 to 22 carbon atoms. 16. A tire according to claim 15 wherein the primary amine of formula (II) is such that R represents a hydrocarbon group comprising from 12 to 20 carbon atoms and preferably from 14 to 20 carbon atoms. 17. A tire according to any one of the preceding claims wherein the primary amine of formula (II) bears a radical R which represents a linear hydrocarbon group. 18. A tire according to one of the preceding claims wherein the primary amine of formula (II) bears a radical R which represents an alkyl group or an alkenyl group. 19. Tire according to one of the preceding claims wherein the silica content is 30 to 150 phr. 20. A tire according to any one of the preceding claims, wherein the reinforcing filler comprises carbon black, in a minority. 21. The tire of claim 20 wherein the carbon black content is 0.5 to 50 phr. A tire according to any one of the preceding claims wherein the diene elastomer is selected from the group consisting of polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers and these elastomers. 23. A tire according to any one of the preceding claims wherein the diene elastomer is predominantly composed of non-isoprene diene elastomer. 30 24. A tire according to claim 23 wherein the diene elastomer is composed of 100 phr of non-isoprene diene elastomer. Tire according to one of claims 23 or 24, wherein the non-isoprene diene elastomer is selected from the group consisting of polybutadienes, butadiene copolymers, isoprene copolymers and mixtures of these elastomers. 25- 47 - 26. The tire according to claim 1, wherein the composition further comprises a plasticizer, preferably chosen from plasticizing resins, extension oils and mixtures thereof. 27. A tire according to claim 26 wherein the level of plasticizer is 5 to 100 phr. 28. Tire according to one of the preceding claims wherein the composition is further free of zinc or contains less than 0.5 phr, preferably less than 0.3 phr. 29. The tire according to one of the preceding claims further comprising a coupling agent. 30. The tire according to claim 29, in which the coupling agent is a hydroxysilane polysulfide corresponding to the general formula (IV): (HO), R (3a) Si-R '-Sx-R' -SiR ( 3b) (OH) b (IV) in which: the radicals R, which are identical or different, are hydrocarbon groups preferably comprising from 1 to 15 carbon atoms; the radicals R ', which are identical or different, are divalent linking groups preferably comprising from 1 to 18 carbon atoms; a and b, identical or different, are 1 or 2; x is a number greater than or equal to 2. The tire of claim 30 wherein the coupling agent is a monohydroxysilane wherein a and b are 1. 32. A tire according to any one of claims 30 or 31 wherein the hydroxysilane polysulfide corresponding to the general formula (IV) is such that the radicals R are chosen from C 1 -C 6 alkyls, C 5 -C 8 cycloalkyls, or a phenyl radical; the radicals R 'are chosen from C1-C18alkylenes or arylenes at 06-012. Tire according to any one of claims 30 to 32, in which the hydroxysilane polysulfide corresponding to the general formula (IV) is such that the radicals R are chosen from C1-C6 alkyls and the R radicals. from C 1 -C 10 alkylenes. Tire according to any one of claims 30 to 33, in which the hydroxysilane is a polysulfide of monohydroxysilane of formula (V): ## STR1 ## in which the radicals R are alkyls in Cl-03, preferably methyl; the R 'radicals of the C1-C4 alkylenes, preferably methylene, ethylene or propylene; x is greater than or equal to 2. 35. A tire according to any one of claims 30 to 34 wherein the hydroxysilane is a bis (propyldimethylsilanol) polysulfide of particular formula (Va): ## STR2 ## 36. Tire according to one of the preceding claims wherein the composition comprising the triazine compound of formula (Ia) or (Ib) and the primary amine of formula (II) is the composition of a tire layer selected from the group. consisting of all or part of the tread, all or part of the tire belt and their combinations. 37. A tire according to claim 36 wherein the composition comprising the triazine compound of formula (Ia) or (Ib) and the primary amine of formula (II) is that of all or part of the tread.