WO2012140251A1

WO2012140251A1 - Rubber composition comprising a thiadiazole derivative

Info

Publication number: WO2012140251A1
Application number: PCT/EP2012/056899
Authority: WO
Inventors: Anne Veyland; Nicolas Seeboth
Original assignee: Compagnie Generale Des Etablissements Michelin; Michelin Recherche Et Technique S.A.
Priority date: 2011-04-14
Filing date: 2012-04-16
Publication date: 2012-10-18
Also published as: FR2974098B1; FR2974098A1; CN103597023A; CN103597023B

Abstract

The invention relates to a rubber composition for the production of tyres, containing one or more diene elastomers, one or more reinforcing fillers and a vulcanisation system. The composition is characterised in that the vulcanisation system comprises one or more thiadiazole compounds selected from among compounds having formula (I) and (II). The invention also relates to specific thiadiazole derivatives.

Description

I.

Rubber composition comprising a thiadiazole derivative

The present invention relates to a rubber composition that can be used in particular for the manufacture of tires or semi-finished products for tires such as treads, said composition being based on a diene elastomer, a reinforcing filler and a vulcanization system comprising a particular thiadiazole compound.

The vulcanization of diene elastomers by sulfur is widely used in the rubber industry, in particular that of the tire. In order to vulcanize the diene elastomers, a relatively complete vulcanization system comprising, in addition to sulfur, a primary vulcanization accelerator, such as benzothiazole ring sulfenamides, as well as various secondary accelerators or vulcanization activators, especially derivatives thereof, is used. zinc such as zinc oxide (ZnO) alone or used with fatty acids.

Benzothiazole ring sulfenamides used as primary accelerators for vulcanization are, for example, N-cyclohexyl-2-benzothiazylsulphenamidc (abbreviated as "CBS"), N, N-dicyclohexyl-2-benzothiazylsulfenamide (abbreviated "DCBS"), N-tert-butyl-2-benzothiazyl sulfenamide (abbreviated as "TBBS") and mixtures of these compounds.

As primary vulcanization accelerator, 2- (1,3-benzothiazol-2-yldithio) -1,3-benzothiazole (abbreviated as "MBTS") is also known.

The rubber compositions must have sufficient crosslinking while maintaining an acceptable compromise between the different rheometric properties.

In response to this problem, the Applicant has discovered a novel rubber composition comprising as a vulcanization accelerator a novel thiadiazole compound. This new rubber composition makes it possible to obtain a composition vulcanized using accelerators alternative to known accelerators, ideally with a compromise of rheometric properties similar to that obtained with rubber compositions containing vulcanization accelerators conventionally used.

The invention therefore has for object and a rubber composition for the manufacture of tires, based on one or more diene elastomers, one or more reinforcing fillers and a vulcanization system, said vulcanization system comprising one or more several thiadiazole compounds chosen from compounds of formula

and

or

R i is independently H or a C ₁ -C ₂₅ 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, sulfur exception

-A is selected from

- -H,

- a group

or

R ₂ is identical to R _ls

x 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 R ₃ , R ₅ and R ₅ independently represent a C ₁ -C ₈ hydrocarbon group,

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 R is a hydrocarbon group in C _\ -C _\% , n group

where R ₇ is a C ₁ -C 18 hydrocarbon group,

- a group

where Y is a C 1 -C 18 hydrocarbon chain, optionally interrupted or substituted by one or more heteroatoms;

R ₈ is a Ct-Cig hydrocarbon group, upe

where X is a C 1 -C ₈ hydrocarbon-based chain, optionally interrupted or substituted by one or more heteroatoms; R ₉ and Rio independently represent a hydrocarbon group C 1 -C ₈ , and group

where Ru is H or a C ₁ -C ₁ hydrocarbon group,

M ^{n +} represents a metallic or non-metallic cation, n represents an integer varying between 1 and 4.

In the formulas which precede and which follow, the arrow (->) designates the point of attachment of the groups A and A "to the sulfur atom respectively of the formulas (I) and (Γ).

The invention also relates to a method for preparing a rubber composition for the manufacture of tires according to the invention, comprising the following steps:

- Incorporating at least one of said diene elastomers, during a first step, the reinforcing filler (s), by kneading thermomechanically all, in one or more times, until reaching a maximum temperature between 1 10 ° C and 190 ° C;

- Then incorporate, in a second step, the crosslinking system and knead the whole to a maximum temperature below 1 1 0 ° C.

Preferably, the invention relates to the process as defined above, in which between the thermomechanical mixing and the incorporation of the crosslinking system, the whole is cooled to a temperature of less than or equal to 100 ° C. . Preferably in this case, the last step is performed on a second mixer.

The invention also relates to the use of a composition according to the invention for the manufacture of a finished article or a semi-finished product intended for a motor vehicle ground connection system, such as a pneumatic tire. , internal safety support for tire, wheel, rubber spring, elastomeric joint, other suspension and anti-vibration element. In particular, the composition according to the invention can be used for the manufacture of semi-finished rubber products intended for tires, such as treads, crown reinforcing plies, sidewalls, reinforcing plies. carcases, beads, protectors, underlayments, rubber blocks and other internal rubbers, in particular decoupling erasers, intended to provide the connection or the interface between the aforementioned zones of the tires.

The invention further relates to a finished article or semifinished product for a ground connection system of a motor vehicle, in particular tires and semi-finished products for tires, in particular treads, comprising a composition according to the invention. The tires according to the invention are particularly intended for passenger vehicles, two-wheelers, as for industrial vehicles chosen from vans, "heavy goods vehicles" - ie metros, buses, road transport vehicles (trucks, tractors, trailers ), off-the-road vehicles, agricultural or civil engineering machinery, aircraft, other transport or handling vehicles. The invention further relates to the use as a vulcanization accelerator in a composition based on one or more diene elastomers, one or more reinforcing fillers and a vulcanization system, of one or more thiadiazole compounds. of formula (I) and / or (II).

The invention finally relates to a thiadiazole of formula

or

R _represents H or a hydrocarbon group Ct-C ^ selected from linear alkyl groups, branched or cyclic aralkyl groups, alkylaryl groups and aryl groups, and optionally interrupted by one or more heteroatoms, with the exception of sulfur

-A _a is selected from

- a group

where R _3a , R _4a and R _5a independently represent a C 1 -C ₁₈ hydrocarbon group, with the proviso that R 1 _a does not represent a methyl group,

y _a 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, a group

that R does not represent a methyl group or a phenyl group, eg

where X _a is a C1-C12 hydrocarbon chain, optionally interrupted or substituted by one or more heteroatoms; R.9 and _has Rjoa independently represent a hydrocarbon group d-Cig, and group

where R 1 is H or a C 1 -C ₁₈ hydrocarbon group containing no heteroatom, with the proviso that R is hydrogen.

The invention as well as its advantages will be readily understood in the light of the description and the following exemplary embodiments.

I. Measurements and tests

The compounds synthesized as vulcanization accelerators have been characterized by mass spectrometry and NMR with the apparatus and methods indicated below. Mass spectrometry

The structural analysis of the expected product as well as the determination of the impurity structures were carried out by ID / IC analysis (direct introduction to mass spectrometry with chemical ionization as ionization mode).

Operating conditions:

Reactant gas: methane / ammonia (85/15) at 2ml / min Source temperature: 200 ° C

Swept mass range: 50 to 1000ra / z

NMR

The structural analysis as well as the determination of the molar purities of the synthesis molecules are carried out by NMR analysis. The spectra are acquired on a BRUKER 500 MHz Avance spectrometer equipped with a BBIz-grad 5 mm wideband probe. The quantitative 1H NMR experiment uses a 30 ° single pulse sequence and a 3 second repetition time between each of the 64 acquisitions. The 1 H NMR spectrum coupled to the 2D HSQC 1 H / 13 C and HMBC 1 H / 13C experiments allows the structural determination of the molecules (see allocation tables). The molar quantifications are made from the quantitative 1H-1H NMR spectrum.

The rubber compositions, in which the thiadiazole vulcanization accelerators are tested, are characterized, before and after curing, as indicated below. rheometry

The measurements are carried out at 150 ° C. with an oscillating chamber rheometer according to DIN 53529 - Part 3 (June 1983). The evolution of the rheometric torque, ACouple (in dN.m), in function time depicts the evolution of the stiffening of the composition as a result of the vulcanization reaction. Measurements are processed according to DIN 53529 - Part 2 (March 1983) (with the exception of the conversion rate constant): T ₀ is the induction time, ie the time required for beginning of the vulcanization reaction; T _a (e.g., T99) is the time required to achieve a conversion of a%, ie, a% (e.g., 99%) of the difference between the minimum and maximum torque.

The conversion rate constant denoted by K (expressed in min ^-1 ), of order 1, calculated between 30% and 80% of conversion, which makes it possible to evaluate the kinetics of vulcanization, is also measured. by measuring the slope of the rise in torque on the rheogram of cooking at 1 0 ° C.

II. Conditions of realization of the invention

As explained above, the composition according to the invention is based on one or more diene elastomers, one or more reinforcing fillers and a vulcanization system.

By the term "composition based on" is meant a composition comprising the mixture and / or the reaction product of the various constituents used, some of these basic constituents being capable of or intended to react with one another, at least partly, during the various phases of manufacture of the composition, in particular during its vulcanization.

In the present description, unless expressly indicated otherwise, all percentages (%) are% by weight. In another art, any range of values referred to as "between a and b" represents the range of values from more than a to less than b (i.e., excluding terminals a and b) while any range of values designated by the term "from a to b" means the range of values from a to b (ie including the strict limits a and b). II-1. Diene elastomer

By elastomer or "diene" rubber, should be understood in known manner an elastomer derived at least in part (i.e., a homopolymer or a copolymer) of monomers dienes (monomers bearing two carbon-carbon double bonds, conjugated or not).

These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". The term "essentially unsaturated" is generally understood to mean a diene elastomer derived at least in part from conjugated diene monomers, having a level of units or units of diene origin (conjugated dienes) which is greater than 15% (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%.

Given these definitions, 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, he

as for example elastomers obtained from ethylene, propylene with a non-conjugated diene monomer of the aforementioned type, such as, in particular, hexadiene-1,4, 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, the person skilled in the tire art will understand that the present invention is preferably implemented with essentially unsaturated diene elastomers, in particular of the type (a) or (b). ) above.

As 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- 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 may be, for example, block, random, sequenced or microsequential, and may be prepared in dispersion, in emulsion 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 linkage C-Sn 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 Pat. No. 6,013,718 or WO 2008/1 41702) alkoxysilane groups (as described for example in FR 2,765,882 or US 5,977,238), carboxyl groups (as described for example in WO 01/92402 or US 6 81 5 473, WO 2004/096865 or US 2006 / 0089445) or polyether groups (as described for example in EP 1 127 909, US 6,503,973 WO 2009 ^ 00750 or WO 2009/000752). Other examples of functional elastomers include elastomers (such as SBR, BR, NR or IR) of the epoxidized type.

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%) in cis -1, 4 greater than 80%, polyisoprenes, copolymers of butadiene-styrene and in particular those having a Tg (glass transition temperature, measured according to ASTM D3418) of between 0 ° C. and -70 ° C. and more particularly between -0 ° C. and -60 ° C., 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 (% molar) in trans-1,4 bonds between 10% and 80%, butadiene-isoprene copolymers and especially those having an isoprene content of between 5% and 90% by weight and a Tg of -40 ° C to -10 ° C. 80 ° C, the isoprene-styrene copolymers and especially those having a styrene content of between 5% and 50% by weight and a Tg comp between 5 ° C and - 50 ° C. In the case of butadiene-styrene-isoprene copolymers, these are especially suitable having a styrene content of between 5% and 50% by weight and more particularly of between 10% and 40%, an isoprene content of between 15% and 15%. 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 (mol%) in units - 1, 2 of the butadiene part of between 4% and 85%, a content (mol%) in trans units -1, 4 of the butadiene part comprises between 6% and 80%, a content (mol%) in units - 1, 2 plus -3, 4 of the isoprene portion of between 5% and 70% and a content (mol%) in trans - 1, 4 units of the isoprenic portion. between 10% and 50%, and more generally any butadiene-styrene-isoprene copolymer having a Tg between -5 ° C and -70 ° C.

In summary, the diene elastomer (s) of the composition according to the invention are preferably chosen from the group of highly unsaturated diene elastomers consisting of polybutadienes (abbreviated as "BR"), synthetic polyisoprenes (IR) and natural rubber ( NR), 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).

According to one embodiment, the diene elastomer is natural rubber.

According to another particular embodiment, the diene elastomer is predominantly (ie, for more than 50 phr) an SBR, whether it is an emulsion-prepared SBR ("ESBR") or a prepared SBR. in solution ("SSBR"), or a blend (mixture) SBR / BR, SBR / NR (or SBR / IR), BR / NR (or BR / IR), or SBR / BR / NR (or SBR / BR / IR). 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 an elevated styrene content, for example 35% by weight, is used in particular. at 45%, a vinyl ring content of the butadiene part comprises 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 predominantly (for more than 50 phr) an isoprene elastomer. This is particularly the case when the compositions of the invention are intended to constitute, in tires, the rubber matrices of certain treads (for example for industrial vehicles), crown reinforcing plies (for example webs, webs, or webs), carcass plies, sidewalls, beads, protectors, underlayments, rubber blocks, and other internal gums providing the interface between the aforementioned areas of the tires.

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), synthetic polyisoprenes (IR), different isoprene copolymers and 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 a synthetic cis-1,4 polyisoprene; Among these synthetic polyisoprenes, polyisoprenes having a content (mol%) of cis-1,4 bonds greater than 90% are preferably used, more preferably still greater than 98%.

According to another particular embodiment, especially when it is intended for a tire sidewall, a tubeless tire sealing inner liner (or other airtight element), the composition according to the invention may contain less than an essentially saturated diene elastomer, in particular at least one EPDM copolymer or a butyl rubber (optionally chlorinated or brominated), that these copolymers are used alone or as a mixture with diene elastomers which are highly unsaturated as mentioned above, in particular NR. or IR, BR or SBR. According to another preferred embodiment of the invention, the rubber composition comprises a blend of one (or more) dienic elastomers known as "high Tg" having a Tg of between -70 ° C. and 0 ° C. and one (or more) diene elastomers, referred to as "low Tg", of 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 molar ratio (% molar) of C 1 -C 4 preferably greater than 95%), B IR, SIR, SBIR, and mixtures of these elastomers. The low-level eletomer Tg 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, from 30 to 100 phr, in particular from 50 to 100 phr, of a high Tg elastomer in a blend with 0 to 70 phr, particularly from 0 to 50 phr, of a low Tg elastomer; according to another example, it comprises for all 100 pce one or more SBR prepared (s) in solution.

According to 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 (mol%) of chains cis-1, 4 greater than 90%, with one or more S-SBR or E-SBR (as elastomer (s) high Tg).

The composition of the invention may contain a single diene elastomer or a mixture of several diene elastomers, the diene elastomer (s) may be used in combination with any type of synthetic elastomer other than diene, or even with polymers other than elastomers. for example thermoplastic polymers. Π-2. Reinforcing charge

Any type of reinforcing filler known for its ability to reinforce a rubber composition that can be used for manufacturing tires, for example an organic filler such as carbon black, a reinforcing inorganic filler such as silica, or a cutting of these two types of filler, including a cut of carbon black and silica.

As carbon blacks are suitable all carbon blacks, including the black ty e HAF, ISAF, SAF conventionally used in tires (so-called pneumatic grade black). Among these, the reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades), for example blacks NI 15, N 134, N 234, N 326, N 31 O, N 339, N 347, N 375, or even more particularly , depending on the intended applications, blacks of higher series (for example N660, N683, N772). The carbon blacks could for example already be incorporated into the isoprene elastomer in the form of a masterbatch (see, for example, applications WO 97/36724 or WO 99/1 6600).

As examples of organic fillers other than carbon blacks, mention may be made of the organic functionalized polyvinylaromatic fillers as described in applications WO-A-2006/069792 and WO-A-2006/069793.

By "reinforcing inorganic filler" is meant in this application, by definition, any inorganic or mineral filler (regardless of its color and origin (natural or synthetic), also called "white" filler, "clear" filler or "non-black filler" as opposed to carbon black, capable of reinforcing on its own, with no other means than an intermediate coupling agent, a rubber composition intended for the manufacture of tires in other words, able to replace, in its reinforcing function, a conventional carbon black of pneumatic grade, such a load is characterized generally, in a known manner, by the presence of hydroxyl groups (-OH) on its surface.

The physical state in which the reinforcing inorganic filler is present is indifferent, whether in the form of powder, microbeads, granules, beads or any other suitable densifying form. Of course, the term "reinforcing inorganic filler" also refers to mixtures of different reinforcing inorganic fillers, in particular highly dispersible siliceous and / or aluminosilic fillers as described hereinafter.

Suitable reinforcing inorganic fillers are, in particular, mineral fillers of the siliceous type, in particular silica (SiO 2), or of the aluminous type, in particular alumina (Al 2 O 3). 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 area 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 Ultrasii 7000 and Ultrasil 7005 silicas from Degussa, the silicas Zeosil 1 165MP, 1 135MP and 1 1 1 5MP from Rhodia, silica Hi-Sil EZ 1 50G from the company PPG, the silicas Zeopol 871 5, 8745 and 8755 from the Huber Company, the silicas with a high specific surface area as described in the application WO 03/16837.

When the composition according to the invention is intended for tire treads with a low rolling resistance, the reinforcing inorganic filler used, in particular if it is silica, preferably has a BET surface area of between 45 and 400. m / g, more preferably between 60 and 300 m ² / g.

In a preferred manner, the total reinforcing filler content (carbon black and / or reinforcing inorganic filler such as silica) is between 20 and 200 phr, more preferably between 30 and 150 phr, the optimum being in a different known manner. according to the particular applications concerned: the level of reinforcement expected on a bicycle tire, for example, is of course less than that required on a tire capable of driving at high speed in a manner sustained, for example a motorcycle tire, a tire for a passenger vehicle or for a commercial vehicle such as a truck.

According to one embodiment of the invention, a reinforcing filler comprising between 30 and 150 phr is used, more preferably between 50 and 120 phr of inorganic filler, particularly of silica, and optionally carbon black; the carbon black, when present, is preferably used at a level of less than 20 phr, more preferably less than 10 phr (for example between 0.1 and 10 phr).

According to another embodiment, the reinforcing filler is carbon black.

In order to couple the reinforcing inorganic filler to the diene elastomer, an at least bifunctional coupling agent (or bonding agent) is used in known manner to ensure a sufficient chemical and / or physical connection between the inorganic filler ( surface of its particles) and the diene elastomer, in particular organosilanes or bifunctional polyorganosiloxanes.

In particular, polysulfide silanes, called "symmetrical" or "asymmetrical" silanes according to their particular structure, are used, as described for example in the applications WO03 / 002648 (or US 2005/016651) and WO03 / 002649 (or US 2005/016650).

In particular, polysulphide silanes known as "symmetrical" silanes having the following general formula (III) are suitable in the following non-limiting definition:

(III) Z - D - S _p - D - Z, wherein:

p is an integer of 2 to 8 (preferably 2 to 5);

- D is a divalent hydrocarbon radical (preferably alkylene groups C iC ig or arylene _groups, C ₆ -C i _2, especially alkylenes iC C io, in particular C 1 -C 4, particularly propylene) ;

Z is one of the following formulas:

in which:

the radicals R ₂ i, substituted or unsubstituted, which are identical to or different from one another, represent a Ci-Cs alkyl, C ₅ -C g cycloalkyl or C ₆ -C ₁₈ aryl group (preferably C ₁ -C alkyl groups); ₆ , cyclohexyl or phenyl, especially C1-C4 alkyl groups, more particularly methyl and / or ethyl).

the radicals R ₂ , substituted or unsubstituted, which are identical to or different from one another, represent a C 1 -C 18 alkoxyl or C ₅ -C ₈ cycloalkoxyl group (preferably a group chosen from C ₁ -C ₈ alkoxyls and C ₅ cycloalkoxyls); -Cg, more preferably still a group selected from C ₁ -C ₄ alkoxyls, in particular methoxyl and ethoxyl).

In the case of a mixture of polysulfurized alkoxysilanes corresponding to formula (III) above, in particular common commercially available mixtures, the average value of "p" is a fractional number preferably between 2 and 5, more preferably close to 4, But the invention can also be advantageously implemented for example with disulfide alkoxysilanes (p = 2).

By way of examples of polysulphurized silanes, mention may be made more particularly of the bis (C ₁ -C ₄ ) alkoxy (C ₁ -C ₄ ) alkylsilyl-alkyl (C ₁ -C ₄ ) polysulfides (especially disulfides, trisulphides or tetrasulfides). C ₄ )) _s such as polysulfides of bis (3-trimethoxysilylpropyl) or bis (3-triethoxysilylpropyl). Among these compounds, bis (3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT, of formula [(C ₂ H ₅ O) 3 Si (CH ₂ ) ₃ S ₂ ] ₂ or bis (triethoxysilylpropyl) disulphide is especially used. ), abbreviated TESPD, of formula [(C ₂ H ₅ O) 3 Si (CH ₂ ) 3 S] ₂ . Some examples polysulfides (especially disulfides, trisulphides or tetrasulphides) of bis (monoalkoxyl (C ₁ -C ₄ ) -dialkyl (C ₁ -C ₄ ) silyipropyl), more particularly bis-monoethoxydimethylsilylpropyl tetrasulfide as described in US Pat. WO 02/083782 (or US 2004/132880).

As coupling agent other than polysulfurized alkoxysilane, mention may be made in particular of bifunctional POS (polyorganosiloxanes) or hydroxysilane polysulfides (R ₂₂ ⁼ OH in formula III above) as described in the WO 02/30939 (or US Pat. No. 6,774,255) and WO 02/3 1041 (or US 2004/051210), or also silanes or POS bearing functional azodicarbonyl groups, as described, for example, in the patent applications WO 2006 / 125532, WO 2006/125533, WO 2006/125534.

In the rubber compositions according to the invention, the content of coupling agent is preferably between 4 and 12 phr, more preferably between 3 and 8 phr.

Those skilled in the art will understand that, as the equivalent filler of the reinforcing inorganic filler described in this paragraph, it would be possible to use a reinforcing filler of another nature, in particular an organic filler, since this reinforcing filler would be covered with a filler. inorganic layer such as silica, 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.

II.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 productive 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.

The primary vulcanization accelerator must allow crosslinking of the rubber compositions in commercially acceptable times, while maintaining a minimum safety period ("toasting time") during which the compositions can be shaped without the risk of premature vulcanization. ("Roasting").

According to the invention, the vulcanization system of the composition according to the invention comprises, as primary vulcanization accelerator, one or more thiadiazole compounds chosen from compounds of formula

or R 1 independently represents H or a C 1 hydrocarbon group. -C 25 selected from linear, branched or cyclic alkyl groups, aralkyl groups, alkylaryl groups and aryl groups, and optionally interrupted by one or more heteroatoms, with the exception of sulfur

-A is selected from

- H,

or

R.2 is identical to Ri,

x is an integer greater than or equal to 1, preferably less than or equal to 10, more preferably less than u equal to 8 and most preferably less than or equal to 6, roup

in which R ₃ , R 4 and R ₅ independently represent a C 1 -C 18 hydrocarbon group,

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 most preferably less than or equal to 6, - a group

where Rg is a hydrocarbon group of C _\ -C _\, n group

where R ₇ is a C1-C18 hydrocarbon group,

where Y is a C1-C18 hydrocarbon chain, optionally interrupted or substituted by one or more heteroatoms; Rg is a hydrocarbon group Ci-Cie, upe

where X is a C1-C18 hydrocarbon chain, optionally interrupted or substituted by one or more heteroatora; R ₉ and RJO independently represent a hydrocarbon group having 1 to ₁₈ carbon atoms, and

where Ru is H or a C1-C12 hydrocarbon group,

M ^{n +} represents a metallic or non-metallic cation,

n represents an integer varying between 1 and 4, The compounds of formula (I) or (II) may advantageously replace all or part of the sulfenamide compounds conventionally used.

The term "cyclic alkyl group" means 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 of said chain, or between one or more hetero atoms. carbon atom 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, R _\ represents H.

According to a second embodiment, R 1 represents a methyl group.

The compound (s) of formula (I) are advantageously chosen from compounds whose group A is the group

where x and R.2 are as defined above.

The groups R ₃ to Ru 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.

The X and Y groups may be independently selected from linear, branched or cyclic alkylene groups, arylene groups and alkylarylene groups.

The cation M ^{n +} may be a metal cation chosen from Zn ²⁺ ,

Cu ²⁺ , Na ⁺ , K ⁺ and Li ⁺ . The cation M ⁿ may be a non-metallic cation such as an ammonium ion, for example the ion NMe ₄ ⁺ , NH ₄ ⁺ or H ₃ NMe ⁺ .

According to a particular embodiment, R _3, R ₄ and R ₅ represent a methyl group.

According to a particular embodiment, R ₆ represents a C 1 -C 4 alkyl, more preferentially a C 1 -C 3 alkyl and very preferably a methyl group or an ethyl group.

According to a particular embodiment, R ₇ represents a C 1 -C 4 alkyl, more preferentially a C 1 -C 3 alkyl and very preferably a methyl group or an ethyl group, or R ₇ represents an aralkyl group. as for example a benzyl group.

According to a particular embodiment, Y represents a C 1 -C 4 alkylene, more preferably a C 1 -C 3 alkylene and very preferably a propylene group or an ethylene group and R 8 represents a C 1 -C 4 alkyl, more preferably C ₁ alkyl _; -C ₃ and very preferably a methyl group or an ethyl group.

According to one particular embodiment, X represents a C 1 -C 4 alkylene, more preferably a C 1 -C 3 alkylene and very preferably a methylene group or an ethylene group, and R 9 and 10 independently represent a C 1 alkyl group. C4, more preferentially C ₁ alkyl _; -C ₃ and very preferably a methyl group or an ethyl group.

According to a particular embodiment, Ru represents H.

As particular compounds of formula (I), mention may be made of the following compounds:

The compound (s) of formula (I) and / or (II) generally represent 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 to 1 phr. 5 to 5 pce.

The vulcanization system of the composition according to the invention may also comprise one or more additional primary accelerators, in particular thiuram family compounds, zinc dithiocarbamate derivatives, sulfenamides, guanidines or thiophosphates.

II-4. Various additives

The rubber composition according to the invention may also comprise all or part of the usual additives normally used in elastomer compositions intended for the manufacture of tires, in particular treads, for example plasticizers or extension oils. , whether the latter are of aromatic or non-aromatic nature, pigments, protective agents such as anti-ozone waxes (such as C32 ST Ozone wax), chemical antiozonants, anti-oxidants (such as the paraphenyl enedi amine), anti-fatigue agents, reinforcing resins, acceptors (for example phenolic novolac resin) or methylene donors (for example HMT or H3M) as described for example in the application WO 02/1 0269.

Preferably, the composition according to the invention comprises, as preferred non-aromatic or very weakly aromatic plasticizer, at least one compound selected from the group consisting of naphthenic, paraffinic, MES, TDAE, ester (especially trioleates) of glycerol, plasticizing resins hydrocarbon compounds having a high Tg preferably greater than 30 ° C, and mixtures of such compounds.

The composition according to the invention may also contain, in addition to the coupling agents, activators for coupling the reinforcing inorganic filler or, more generally, processing aid agents that are capable in a known manner, by means of an improvement in the dispersion of the inorganic 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 (especially alkyltriethoxysilanes), polyols, polyethers (for example polyethyleneglycols), primary, secondary or tertiary amines (for example trialkanol amines), hydroxylated or hydrolysable POSs, for example α, ω-dihydroxy-polyorganosiloxanes (especially σ, ω-dihydroxy-polydimethylsiloxanes), fatty acids such as, for example, stearic acid.

II -5. Manufacture of rubber compositions

The rubber composition according to the invention is manufactured in suitable mixers, generally using two successive preparation phases according to a general procedure well known to those skilled in the art: a first working phase or thermomechanical mixing (sometimes referred to as "non-productive" phase) at high temperature, up to a maximum temperature of between 110 ° C. and 190 ° C., preferably between 115 ° C. and 150 ° C. and even more preferably between 115 ° C. and 140 ° C, followed by a second phase of mechanical work (sometimes referred to as a "productive" phase) at a lower temperature, typically below 1 10 ° C, for example between 40 ° C and 100 ° C, finishing phase during which may be incorporated the crosslinking system or vulcanization. According to a preferred embodiment of the invention, all the basic constituents of the composition of the invention, with the exception of the vulcanization system, namely the reinforcing filler or fillers, the coupling agent, if appropriate, are intimately incorporated, by kneading, with the diene elastomer or the diene astomers during the so-called non-productive first phase, that is to say that is introduced into the mixer and that one thermomechanically knead, in one or more steps, at least these different basic constituents until the maximum temperature is reached between 110 ° C. and 190 ° C., preferably between 15 ° C. and 150 ° C.

The two phases can be carried out consecutively on the same mixer or be separated by a cooling step at a temperature below 100 ° C., the last step then being carried out on a second mixer.

By way of example, the first (non-productive) phase is carried out in a single thermomechanical step during which all the necessary constituents, the possible setting agents, are introduced into a suitable mixer such as a conventional internal mixer. Complementary applications and other miscellaneous additives, with the exception of the vulcanization system. The total mixing time in this non-productive phase is preferably between 1 and 15 minutes. After cooling the mixture thus obtained during the first non-productive phase, the vulcanization system is then incorporated at low temperature, generally in an external mixer such as a roller mixer; the whole is then mixed (productive phase) for a few minutes, for example between 2 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 else extruded in the form of a rubber profile that can be used, for example, as a tread. tire for passenger vehicle.

Alternatively, all of the basic constituents of the composition, including the crosslinking system, ie the reinforcing filler or fillers, the coupling agent, if any, are intimately incorporated, by kneading, with the diene elastomer or the diene elastomers in a single step. In this case, the working phase or thermomechanical mixing reaches a maximum temperature of 120 ° C.

II-6. Particular thiadiazole compounds

The subject of the invention is also a particular thiadiazole of formula

or

R 1a represents H or a C 1 -C 25 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, with the exception of sulfur

-A _a is selected from

pe

wherein R 3 _a , R _4a and sa independently represent a C 1 -C 15 hydrocarbon group, with the proviso that R does not represent a methyl group, y _a 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, n group

wherein R _7a is a hydrocarbon group-Ci _8, provided that Ria is not a methyl group or a phenyl group, pe

where X _a is a C ₃ -C ₁₈ hydrocarbon chain, optionally interrupted or substituted by one or more heteroatoms; R.9a and Rioa independently represent a C1-C18 hydrocarbon group, and

where Rua is H or a hydrocarbon group in CJ-CJS containing no heteroatom, with the proviso that R _a represents hydrogen.

By cyclic alkyl group is meant an alkyl group consisting of one or more rings.

By hydrocarbon group or 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 a carbon atom 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.

R _3iL groups Rs _a, R _7a, R.9a RIOA and may be independently selected from linear, branched or cyclic, aryl groups, aralkyl groups and alkylaryl groups, optionally interrupted by one or more heteroatoms.

Rn _group may be selected from hydrogen, linear alkyl groups, branched or cyclic, aryl groups, aralkyl groups and alkylaryl groups.

According to a preferred embodiment, when A _a is a group of formula C (O) OR _7a , Ri "represents H or a C ₂ -C 18 linear hydrocarbon group.

The group X _a is generally chosen from linear, branched or cyclic alkylene groups, arylenes and alkylarylenes, optionally interrupted by one or more heteroatoms.

According to a particular embodiment, R _3a , R _4a and R _5a represent a methyl group.

According to a particular embodiment, R _7a represents a C ₁ -C ₄ alkyl, more preferentially a C ₁ -C ₃ alkyl and very preferably a methyl group or an ethylc group, or R _7a represents an aralkyl group such that for example a benzyl group.

According to a particular embodiment, X _a represents a C1-C4 alkylene, more preferably a C1-C3 alkylene and very preferably a methylene group or an ethylene group, and R _a and Rioa independently represent a C-alkyl group. _\ - C _4, more preferably an alkyl-C ₃ and very preferably, methyl or ethyl. According to a particular embodiment, Rua represents H.

II-7. Preparation of accelerators of general formula (I), (II) and (Γ)

Those skilled in the art can prepare the thiazoline compounds of general formula (I), when the group A represents a hydrogen atom, in which case the thiazolines are substituted by a thiol. This thiol may be salified by techniques known to those skilled in the art to obtain the thiolate compounds of general formula (II).

From thiols or thiolates described above and according to the nature of the group A, the skilled person can obtain the compounds of general formula (I) or (Γ) as indicated below:

- When radical A represents a group

as defined above, the compound can be prepared by an oxidative coupling.

To a solution of the precursor thiol is added an organic or inorganic oxidizing agent (for example diisopropylazodicarboxylate or ammonium persulfate, or alternatively iodine or a solution of sodium hypochlorite). For example, this type of procedure is described in the following documents:

with NaOCl by Mathes in US2 196607 (1940),

with (H ₄ ) ₂ S ₂ O ₈ in Stewart, Mathes, J. of Chem., 1949, vol. 1 4, p. 1 1 1 1 ^■ · - 1 1 1 7.

By this reaction we obtain the derivatives in which x = 1. To obtain compounds in which x is greater than 1, sulfur atoms may be inserted into the existing sulfur-sulfur bond, for example by reaction with triphenyl thiosulfenyl chloride. in dichloromethane in the presence of acetic acid, as proposed for example in Tehrahedron Letters, Volume 41, Issue 37, September 2000, Pages 7169-71 72.

- When the radical A or Aa represents a group

as previously defined, the synthesis route may be similar to that described for the foregoing compounds.

For example, Birch describes the oxidative coupling of methyl mercaptan with tertbutyl mercaptan in the presence of potassium hexacyanoferrate (III) (Birch et al., Journal of the Institute of Petroleum, 1953, 39, 206, 210).

It is also possible to follow another procedure consisting in carrying out a redistribution reaction of a symmetrical disulfide in the presence of an alkyl mercaptan as described, for example, by Brzezinska, Ewa; Ternay, Andrew L., Jr. in the article Disulfides Syntheses Using 2, 2 '- Dithiobis (Benzothiazole), Journal of Organic Chemistry (1994), 59, 8239-8244. This method consists in making a reaction in chloroform between a symmetrical disulfide and a mercaptan such as tert-butyl mercaptan, which leads to a redistribution.

By this reaction, the derivatives in which y = 1 are obtained. In order to obtain the compounds in which y is greater than 1, sulfur atoms may be inserted into the existing sulfur-sulfur bond, for example by reaction with triphenylthiosulfenyl chloride in dichloromethane in the presence of acetic acid, as proposed for example in Tehrahedron Letters, Volume 41, Issue 37, September 2000, Pages 7169-71 72.

- When radical A represents a group

As defined above, this compound may be prepared according to a thioesterification reaction between the thiol or its corresponding thiolate with a carboxylic acid or its derivatives (acid chloride, anhydride) bearing the radical R <j.

For example, Jan Larsen and Christine Lenoir in Organic Syntheses, Coll. Flight. 9, p. 72 (1998), describe a thioesertification reaction between a thiol and an acid chloride in the presence of triethylamine to trap the hydrochloric acid formed, the reaction being conducted in dichloromethane at 0 to 10 ° C.

- When the radical A or Aa represents a group

as defined above, this compound may be prepared by addition-elimination reaction between the thiol and an alkyl chloroformate bearing the radical R ₇ or R _7a which may itself be commercially available or prepared by reaction between an alcohol and phosgene or a derivative thereof. An organic or inorganic base can be added to trap the hydrochloric acid formed.

This approach is described by Taylor, Roger in the Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry (1972-1999), 1983, p. 291-296. The authors react ethyl mercaptan with methyl chloroformate in the presence of pyridine.

Instead of using the thiol, it is possible to use the corresponding thiolate. This approach is described by Suzuki, Shigenori; Hisamichi, Kanehiko; In C, Katsuya in Heterocycles, 1993, vol. 35, # 2 p. 895-900. The authors react sodium metylthiolate with methyl chloroformate to obtain the thiocarbonate derivative. Another synthetic route is to react the thiol or its thiolate with phosgene (Chen W. W. et al., Journal of the American Chemical Society, 1978, vol 100, pp. 2370-2375) or a derivative thereof such as triphosgene (WO2008 / 038 1 75) optionally in the presence of an inorganic or organic base such as a tertiary amine for example to form the chlorothioformate intermediate. This intermediate can then react with an alcohol in the presence of an organic base such as a tertiary amine to form the thiocarbonate compound. This approach is for example described in Organic

Syntheses, Coll. Flight. 5, p. 166 (1973); Flight. 44, p.20 (1964).

- When radical A represents a group

as defined above, this compound may be prepared by nucleophilic substitution between the thiol or its thiolate and an ester substituted with a halogenated group and carrying the radicals Y and R ₈ such as, for example, bromoethylacetate or 4-bromo methylbutyrate.

For example, the reaction between 3-mercapto-5,6-diphenyl-1,2,4-triazine and ethyl 3-bromo-propionate in ethyl acetate in the presence of triethylamine to trap acid hydrobromic formed is described by Bhalla, M .; Srivastava, V.; Bhalla, T.N. ; Shanker,. in Bolleitino Chimico Farmaceutico (1995), 134 (1), 9-15. - When the radical A or Aa represents a group

as defined above, this compound may be prepared by nucleophilic substitution between the thiol or its thiolate and a halogenated derivative of a phosphonate or a phosphonic acid carrying the X, Rg and Rio or Xa, Rg _a and Rio _a radicals, and more particularly with a bromo or chloro alkyl phosphonate.

This reaction is described, for example, for the reaction between diethyl (2-bromoethyl) phosphonate and sodium ethanethiolate in an ether (Mikolajczyk, Marian, Costisella, Burkhard, Grzejszczak, Slawomir, Tetrahedron, 1983, vol 39, # 7, pp. 1189-1193).

- When the radical A or Aa represents a group

As defined above, this compound can be prepared by nucleophilic substitution between the thiol or its thioate and an allyl haiogenide carrying the radical Ru or u _a and for example between the thiol and allyl bromide.

For example, the reaction between a triazine thiol and an allyl haiogenide in the presence of potassium hydroxide in alcohol is described in patent BE 503980 of the Belgian Society for Nitrogen and Chemicals Marly (1951).

An example of a compound of formula (I) is 1, 3, 4-thiadiazole-2 (3H) -thionc of formula

marketed by ABCR for example.

Another example of a compound of formula (I) is the compound of the following formula

described in the document Polysulfide compounds as high energy cathode of lithium batteries; Naoi, Katsuhiko; Kawase, Ken-ichi; Inoue, Yoshinori; Electrochemical Society, Volume 96, Pages 131-138, 1996.

Another compound of formula (I) is the compound of the following formula

described in Bis (1,3,4-thiadiazol-2-yl) disulphide,

Hu, Pu Zhou; Zhang, Yong Hua; Wang, Jian Ge; Qin, Jian Hua; Zhao, Bang Tun, Âcta Crystallographica, Section E: Structure Reports Online (2009). 111. Examples

III. 1. Synthesis of Compound A: 1.2-Bis (5-methyl-1,3,4-thiadiazol-2-indisulfane

Compound A is described in the publication: Hipler, Frank; Winter, Manuela; Fischer, Roland A. Journal Molecular Structure, 2003, vol. 658, # 3 p. 1 79 - 1 92. This publication proposes the following reaction scheme

reflux, 6 h

The starting material is commercial (Aldrich, CAS 29490-19-5, methyl-1,3,4-thiadiazole-2-thiol).

Compound A may also be prepared according to the following scheme;

To a solution of 5-methyl-1,3,4-thiadiazole-2-thiol (39.58 g, 0.299 mol) in 1.0 L of chloroform is added, per portion for 5 minutes, manganese oxide. (IV) activated (52.05 g, 0.598 mol). The reaction mixture is then stirred and refluxed for 2.5 hours. The reaction mixture is then cooled to 20 ° C. and filtered through Ceite®.

The filtrate is concentrated under reduced pressure (Tbain 30 ° C, 9-1 Ombar) to yield a solid which is then dried in air (33.97 g, 0.11 mol, 87% yield) melting point 1. 13 ° C.

The molar purity is greater than 97% (RM NMR). NMR characterization

The chemical shifts obtained by NMR H and C in DMSO-6 are given in the table below. The calibration is performed on C).

III.2 Examples of composition

Example 1

The purpose of this example is to compare the properties of a rubber composition comprising carbon black and silica, usable for the manufacture of a tire tread, including the MBTS as the primary accelerator of the invention. vulcanization (composition C1), with the properties of a rubber composition according to the invention comprising compound A (composition C2) as a primary vulcanization accelerator. The formulations of the compositions are given in Table I below. The amounts are expressed in parts per 00 parts by weight of elastomer (phr).

Table 1

(1) polybutadiene with 0.7% of 1-2; 1.7% trans 1 -4; 98% of ci s 1 -4 (Tg = -105 ° C) (mol%)

(2) butadiene-styrene copolymer SSBR (SBR prepared in solution) with 25% styrene, 59% of polybutadiene units 1 -2 and 20% of trans-polybutadiene-4 units (Tg = -24 ° C.), {mole% ); rate expressed as dry SBR (extended SBR with 9% by weight of MES oil, ie a total of SSBR + oil equal to 76 phr)

(3) carbon black (4) "Zeosil 1 165MP" silica from Rhodia, type "HDS" (BET and CTAB: approximately 160 m2 / g);

(5) Antioxidant agent 6-para-phenylenediamine

(6) Antiozonant agent

(7) Aliphatic resin (C5 pure) "Hikorez A-100" marketed by the company KOLON

(8) coupling agent

(9) stearic acid: Stearin "Pristeren" from the company Uniquema

(I 0) Diphenylguanidine (Perkacit DPG from Flexsys) * MBTS from G-QUIMICA sold under the trade name Rubator MBTS

The rheometric properties at 150 ° C are given in Table 2 below.

Table 2

The rheometric properties obtained for the compositions according to the invention show that compound A can be used as a vulcanization accelerator in rubber compositions comprising one or more reinforcing fillers.

Example 2

The objective of this example is to compare the properties of a rubber composition comprising carbon black, usable for the manufacture of a tire tread, comprising the MBTS as a primary vulcanization accelerator (composition C 1), with the properties of a rubber composition according to the invention comprising the compound A at different levels (compositions C2 and C3) as the primary accelerator of vulcanization.

The formulations of the compositions are given in Table 3 below. The amounts are expressed in parts per 100 parts by weight of elastomer (phr). Table 3

(1) natural rubber

(2) Stearin "Pristeren" from the company Uniquema

(3) MBTS from the company G-QUIMICA marketed under the reference Rubator MBTS

The rheometric properties at 150 ° C are given in Table 4 below. Table 4

Tests C l C2 C3 k 0.32 0.41 0.21

T0 (min) 1, 25 0.68 1, 63 The rheological properties obtained for the compositions according to the invention show that compound A can be used as a vulcanization accelerator in rubber compositions comprising one or more reinforcing fillers.

Claims

A rubber composition for the manufacture of tires, based on one or more diene elastomers, one or more reinforcing fillers and a vulcanization system, characterized in that said vulcanization system comprises one or more thiadiazole compounds. chosen from compounds of formula

and

Ri is independently H or a hydrocarbon group having ₂₅ iC selected from linear alkyl groups, branched or cyclic aralkyl groups, alkylaryl groups and aryl groups, and optionally interrupted by one or more heteroatoms, with the exception of sulfur

-A is selected from

- -H,

- a group

or

R ₂ is identical to R _ls

x 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, roup

where R ₃ , R ₄ and R ₅ independently represent a C ₁₈ -C ₁₈ hydrocarbon group,

- a group

where R <5 is a hydrocarbon group Cj-C ₁₈ , n group

where R ₇ is a hydrocarbon group in

- a group

where Y is a C1-C18 hydro carbon chain, optionally interrupted or substituted with one or more heteroatoms; Rg is a hydrocarbon group-C _18, the UPE

where X is a C1-C18 hydrocarbon chain, optionally interrupted or substituted with one or more heteroatoms; R9 and RJO independently represent a C1-C18 hydrocarbon group, and group

where R 1 is H or a C ₁ -C 15 hydrocarbon group,

2. Composition according to claim 1, characterized in that Ri represents H.

3. Composition according to claim 1, characterized in that R1 represents a methyl group.

4. Composition according to any one of the preceding claims, characterized in that A is the group

where x and R ₂ are as defined in claim 1.

5. Composition according to any one of the preceding claims, characterized in that the groups R ₃ to Ru are independently selected from linear, branched or cyclic alkyl groups, aryl groups, aralkyl groups and alkylaryl groups, optionally interrupted by one or more heteroatorae.

6. Composition 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, arylenes and alkylarylenes.

7. Composition according to any one of the preceding claims, characterized in that M ^{n +} is a metal cation selected from Zn ²⁺ , Cu ²⁺ , Na 'K ⁺ and Li \

8. Composition according to any one of claims 1 to

6, characterized in that M "'^" is a non-metallic cation.

9. Composition according to any one of the preceding claims, characterized in that the said thiadiazole compound (s) represent 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).

Composition according to any one of the preceding claims, characterized in that the diene clastomer (s) are chosen from the group consisting of polybutadienes, natural rubber, synthetic polyisoprenes, butadiene copolymers, copolymers of soprene and mixtures of these elastomers.

1 1. Composition according to any one of the preceding claims, characterized in that the reinforcing filler (s) are chosen from silica, carbon black and their mixtures, preferably carbon black.

2. Composition according to any one of the preceding claims, characterized in that the reinforcing filler or fillers are present at a level of between 20 and 200 phr, preferably between 30 and 150 phr.

13. Process for preparing a rubber composition for the manufacture of tires as defined in any one of the preceding claims, characterized in that it comprises the following steps:

- Incorporating into said diene elastomers or, in a first step, the reinforcing fillers or by thermomechanically kneading the whole, in one or more times, to reach a maximum temperature between 1 1 0 ° C and 1 0 ° C;

- Then incorporate, during a second step, the crosslinking system and knead the whole to a maximum temperature below 1 1 0 ° C.

14. The method of claim 1 3, wherein between the thermomechanical mixing and the incorporation of the crosslinking system, the whole is cooled to a temperature of less than or equal to 100 ° C.

5. Use of a composition as defined in any one of claims 1 to 12 for the manufacture of a finished article or a semi-finished product for a motor vehicle ground connection system. .

16. Finished article or semi-finished product for a ground connection system of a motor vehicle, comprising a composition as defined in any one of claims 1 to 12.

7. A tire comprising a rubber composition as defined in any one of claims 1 to 12.

18. A tread comprising a rubber composition as defined in any one of claims 1 to 12.

19. Use as a vulcanization accelerator in a composition based on one or more diene elastomers, one or more reinforcing fillers and a vulcanization system, of one or more azole thiadi compounds of formula (I) and or (II) as defined in any one of Claims 1 to 8.

20. Thiadiazole of formula

or

R _represents H or a hydrocarbon group of C i -C ₂₅ selected from linear alkyl groups, branched or cyclic aralkyl groups, alkylaryl groups and aryl groups, and optionally interrupted by one or more heteroatoms, with the exception sulfur

-A _a is selected from

pe

where R.3 _has R.4 "and R _s independently represent a hydrocarbon group-C, with the proviso that R is not methyl,

y _a 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, n group

wherein R _7a is a hydrocarbon group Ci-e, with the proviso that R] _a is not methyl, or a phenyl group,

where _X is a hydrocarbon chain in C i -C i _8, optionally interrupted or substituted by one or more heteroatoms; Rg _a and Rjoa independently represent a hydrocarbon group C 1 -C is, and group

_lla wherein R is H or a hydrocarbon group having iC ₁₈ does not contain a heteroatom, provided that R _a is hydrogen.

21. Thiadiazole according to claim 20, characterized in that the groups R _3a to R _5a , R _7a , R _a and R _a are independently selected from linear, branched or cyclic alkyl groups, aryl groups, aralkyl groups and alkylaryl groups, optionally interrupted by one or more heteroatoms.

22. Thiadiazole according to claim 20, characterized in that the group R _11a is chosen from hydrogen, linear, branched or cyclic alkyl groups, aryl groups, aralkyl groups and alkylaryl groups.

23. thiadiazole according to claim 20, characterized in that when A _a is a group of formula C (0) OR _7n, R _represents H or a linear hydrocarbon group, C ₂ -C 8 i.

24. Thiadiazole according to any one of claims 20 to 23, characterized in that the X _a group is chosen from linear, branched or cyclic alkylene groups, arylenes and alkylarylenes, optionally interrupted by one or more heteroatoms.