EP2697301A2

EP2697301A2 - Rubber composition including a thiazole derivative

Info

Publication number: EP2697301A2
Application number: EP12715381.5A
Authority: EP
Inventors: Anne Veyland; Nicolas Seeboth
Original assignee: Michelin Recherche et Technique SA Switzerland; Compagnie Generale des Etablissements Michelin SCA; Michelin Recherche et Technique SA France
Current assignee: Compagnie Generale des Etablissements Michelin SCA
Priority date: 2011-04-14
Filing date: 2012-04-16
Publication date: 2014-02-19
Also published as: US20140128499A1; US9688852B2; CN103917584B; RU2013150518A; WO2012140258A3; FR2974096A1; JP5997759B2; BR112013026506A2; JP2014519529A; CN103917584A; WO2012140258A2

Abstract

The invention relates to a rubber composition for manufacturing tires, containing one or more diene elastomers, one or more reinforcing fillers, and a vulcanization system, characterized in that said vulcanization system includes one or more thiazole compounds selected from the compounds the following formula (I). The invention also relates to certain specific thiazole derivatives.

Description

Rubber composition comprising a thiazole 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 thiazole 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 complex vulcanization system comprising, in addition to sulfur, a primary vulcanization accelerator, such as sulphonamides with a benzothiazole nucleus, as well as various secondary accelerators or vulcanization activators, in particular zinc such as zinc oxide (ZnO) alone or used with fatty acids.

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

As the primary vulcanization accelerator, 2- (1,3-benzothiazol-2-yldithio) -1,3-benzothiazole (abbreviated as "METS") 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 a thiazole compound as a vulcanization accelerator. This new rubber composition makes it possible to obtain a vulcanized composition 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 relates to 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 thiazole compounds chosen from the compounds of formula (I) below:

in which

R 1 and R ₂ independently represent a hydrogen atom or a C 4 hydrocarbon group; -C ₂₅ selected from linear, branched or cyclic alkyl groups, aralkyl groups, alkyl aryl groups and aryl groups, and optionally interrupted by one or more heteroatoms, Ri and R ₂ may together form a non-aromatic ring, but not can not together form an aromatic ring,

-A is selected from

a hydrogen atom;

- a group

in which

R ₃ , R ₄ and Rs independently represent a C 1 -C ₈ hydrocarbon 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 most preferably less than or equal to 6; a group

in which

R ₆ is a C1-C18 hydrocarbon group optionally interrupted by one or more heteroatoms; a group in which

R ₇ is a C 1 -C ₁₈ hydrocarbon group, optionally interrupted by one or more heteroatoms; a group

in which

Y is a hydrocarbon chain C _\ -C _\ optionally interrupted or substituted by one or more heteroatoms;

Rg is a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms;

- a group

in which

X is a C1-C12 hydrocarbon chain, optionally interrupted or substituted by one or more heteroatoms,

R and Rio independently represent a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms, and

- a group

in which

Ru is a hydrogen atom or a C ₁ -C ₁₈ hydrocarbon group, optionally interrupted by one or more heteroatoms.

In the above formulas and below, the arrow (->) denotes the point of attachment of the groups A and A _has on the sulfur atom respectively of formulas (1) and (). The invention also relates to a method for preparing a rubber composition for the manufacture of tires as defined above, comprising the following steps:

- Incorporating into a diene elastomer, during a first step, the reinforcing fillers or by thermomechanically kneading the whole, in one or more times, to reach a maximum temperature of between 1 10 ° C and 190 ° C ;

- Then incorporate, during 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 subject of the invention is also the use of a composition according to the invention for the manufacture of a finished article or of a semi-finished product intended for a motor vehicle ground connection system, such as a 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 in particular for passenger cars, two-wheelers, as well 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 _. base of one or more diene elastomers, one or more reinforcing fillers and a vulcanization system, of one or more thiazo compounds of formula (I).

The invention finally relates to a thiazole of formula (F) below:

(Γ) in the aquell e

Ru and R _2a independently represent a hydrogen atom or a C 1 -C 25 hydrocarbon group selected from linear, branched or cyclic alkyl groups, aralkyl groups, alkyl aryl groups and aryl groups, and optionally interrupted by one or more heteroatoms, R _a and R _2a may together form a non-aromatic ring, but can not together form an aromatic ring;

is chosen from

- a group

in which

R _a , R 4 _a and _¾ a independently represent a C 1 -C 18 hydrocarbon group, optionally interrupted by one or more heteroatoms,

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,

with the proviso that _the R and R _2a do not simultaneously denote a methyl or a hydrogen atom; aryl and hydrogen;

- a group

in which

R _6a is a C 1 -C 18 hydrocarbon-based group, optionally interrupted by one or more heteroatoms, chosen from linear, branched, cyclic and aralkyl alkyl groups, optionally substituted with one or more halogens, one or more linear or ri linear or branched alkoxy, hydroxy, nitro,

and with the proviso that R and R2a independently denote a hydrogen atom or an alkyl group; a group

in which

R _7a is a C 1 -C ₁₈ hydrocarbon group, optionally interrupted by one or more heteroatoms, and with the proviso that R _a and R _2a represent methyl respectively; a group

in which

X _a is a C 1 to C 18 hydrocarbon-based chain, optionally interrupted or substituted with one or more heteroatoms, but which can not carry another phosphonate group,

Ro _a and Rj oa independently represent a C1-C16 hydrocarbon group, optionally interrupted by one or more heteroatoms,

with the proviso that _the R and R _2a independently represent a hydrogen atom or an alkyl group, a group in which

R u represents a hydrogen atom or a hydrocarbon group of C _\ -C _\%

with the proviso that _the R and R _2a are independently an alkyl group having ₈ iC i.

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 used

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 an ionization mode).

Operating conditions:

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

Swept mass range: 50 to 1000m / 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 BRU ER 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 2D experiments HSQC 1 H / 1 3C and HMBC 1 H / 13C allow the structural determination of the molecules (see allocation tables). Molar quanti fications are made from the quantitative 1 H NMR spectrum.

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

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), as a function of time describes 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): To is the induction delay, ie the time required at the beginning the vulcanization reaction; T _a (for example T99) is the time required to reach a conversion of a%, that is to say a% (for example 99%) of the difference between the minimum and maximum torques.

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. measuring the slope of the rise in torque on the cooking rheogram at 1 50 ° 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. On the other hand, any range of values designated by the expression "between a and b" represents the range of values from more than a to less than b (that is, bounds a and b excluded), while any range of values designated by the expression "from a to b" means the values ranging from a to b (that is to say 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 carrying two carbon-carbon double bonds, conjugated or not ).

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

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, sequenced, microsequenced, and 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. Examples of coupling with carbon black are functional groups comprising a C-Sn bond or amino 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 / 141,702), 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 8 15 473, WO 2004 / 096865 or US 2006/0089445) or else polyether groups (as described for example in EP 1 1 27 909, US 6,503,973 WO 2009/000750 or WO 2009/000752). Other examples of functional elastomers include elastomers (such as SBR, BR, NR or IR) of the epoxidized type.

Suitable are 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 of greater than 80%, polyisoprenes. , butadiene-styrene copolymers and in particular those having a Tg (glass transition temperature, measured according to ASTM D3418) 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 of (mol%) in trans-1,4 ranges between 10% and 80%, butadiene-isoprene copolymers and in particular those having a soprene content of between 5% and 90% by weight and a Tg of - 40 ° C to -80 ° C, isoprene-styrene copolymers and especially those having a styrene content of between 5% and 50% by weight and a Tg between 5 ° C and - 50 ° C. In the Butadiene-styrene-isoprene copolymers are suitable in particular those 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 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 -1,2 units of the butadiene part. 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 isoprenic part of between 5% and 70% and a content (mol%) in trans-1,4 units of the isoprenic part of 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 (B IR), isoprene-styrene copolymers (SIR) and copolymers of isoprene-butadiene-styrene (SBIR).

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

According to another particular embodiment, the diene elastomer is predominantly (Le., For more than 50 phr) an SBR, whether it is an emulsion-prepared SBR ("ESBR") or an SBR prepared 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 a high styrene content, is used, for example from 35 to 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 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 work webs, protective webs or hoop webs), carcass reinforcement plies, flanks, beads, protectors, underlayments, rubber blocks and other internal gums providing the interface between 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 chosen from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), different copolymers of isoprene and mixtures of these elastomers. Among the isoprene copolymers, mention will be made in particular of isobutene-isoprene (butyl rubber-IIR), isoprene-styrene (SIR), isoprene-butadiene (BIR) or isoprene-butadiene copolymers. styrene (SBIR). This isoprene elastomer is preferably natural rubber or a 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.

According to another particular embodiment, especially when it is intended for a tire sidewall, a tubeless tire sealing inner liner (or other impervious element air), the composition according to the invention can contain at least one essentially saturated diene elastomer, in particular at least one EPDM copolymer or a butyl rubber (optionally chlorinated or brominated), whether these copolymers are used alone or in 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 diene elastomers known as "high Tg" having a Tg of between -70 ° C. and 0 ° C. and of a (one or more) diene elastomer called "low Tg" between -1 10 ° 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 preferably greater than 95%), BIR, SIR, SB IR, 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, 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, in particular 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 content (mol%) of cis chains - 1, 4 greater than 90%, with one or more S-SBR or E-SBR (as elastomer (s) high Tg).

The composition according to 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. II-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.

Carbon blacks are suitable for all carbon blacks, in particular blacks of the HAF, ISAF, SAF type conventionally used in tires (so-called pneumatic grade blacks). Among the latter, the reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades), for example blacks NI15, N134, N234, N326, N330, N339, N347, N375, or else, according to the targeted applications, the 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 WO 97/36724 or WO 99/16600).

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 e (whatever its color and origin (natural or synthetic), also called "white" filler, "clear" filler "even" non-black filler "(" non-black filler ") versus 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 pneumatic grade; such a filler is generally characterized, in 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 densified form. Of course, the term "reinforcing inorganic filler" also refers to mixtures of different reinforcing inorganic fillers, in particular highly dispersible siliceous and / or aluminous fillers as described below.

Suitable reinforcing inorganic fillers are mineral fillers of the siliceous type, in particular silica (SiO ₂ ), or 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 both less than 450 m ² / g, preferably from 30 to 400 m ² / g. As highly dispersible precipitated silicas (so-called "HDS"), there may be mentioned, for example, the silicas Ultrasil 7000 and Ultrasil 7005 from the company Degussa, the silicas Zeosil 1 1 65MP, 1 1 35MP and 1 1 1 5MP from the company Rhodia, Hi-Sil silica EZ150G from PPG, silicas Zeopol 8715, 8745 and 8755 from Huber, silicas with a high specific surface area as described in 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.

Preferably, 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 known manner different according to particular applications targeted: the level of reinforcement expected on a bicycle tire, for example, is of course less than that required on a tire capable of running at high speed in a sustained manner, for example a motorcycle tire, a tire for a passenger vehicle or for commercial vehicles such as Heavy Duty.

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 ether, a bifunctional coupling agent (or bonding agent) is used in known manner to provide 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.

Polysulphurized silanes, called "symmetrical" or "asymmetrical" silanes according to their particular structure, are especially used, as described for example in the applications WO03 / 002648 (or US 2005/01 6651) and WO03 / 002649 (or US 2005/01 6650). ).

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 C ₁ -C ₁₈ alkyl groups or C ₆ -C ₁₂ arylene groups, more particularly C 1 -C 10 alkylenes, especially C 1 -C 4 alkylenes, in particular propylene);

Z is one of the following formulas:

in which:

- R _2] radicals, substituted or unsubstituted, identical or different, represent alkyl, Cj-Cig, cycloalkyl C ₅ -C ₁₈ aryl or C ₆ -C ₈ (preferably alkyl groups CJ -C _O, cyclohexyl or phenyl, especially alkyl groups, C1-C4 alkyl, more particularly methyl and / or ethyl).

- R22 radicals, substituted or unsubstituted, identical or different, represent an alkoxyl group Ci-Cjg or cycloalkoxy C5-C18 (preferably a group selected from alkoxyls Cs and cycloalkoxyls Cs-C _8, more preferably still a group selected from C1-C4 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).

As examples of polysulphide silanes, mention may be made more particularly of polysulfides (in particular disulfides, trisulphides or tetrasulfides) of bis- (C ₁ -C ₄ alkoxyl) -alkyl (C ₁ -C ₄ ) silyl-C ₁ -C alkyl ), such as polysulfides of bis (3-trimethoxysilylpropyl) or bis (3-triethoxysilylpropyl). Among these compounds, bis (3-triethoxysilylpropyl) tetrasulfurc, in abbreviated form, is especially used. TESPT, of formula [(C ₂ H ₅ O) ₃ Si (CH ₂ ) ₃ S ₂ ] ₂ or bis (triethoxysilylpropyl) disulfide, abbreviated to TESPD, of formula [(C ₂ H ₅ O) 3 Si ( CH) ₃ S] 2. Preferred polysulfides (especially disulfides, trisulphides or tetrasulfides) of bis- (monoalkyl (C 1 -C ₄ ) -dialkyl (C 1 -C ₄ ) silylpropyl) are also preferred. particularly bis-monoethoxydimethylsilylpropyl tetrasulfide as described in patent application WO 02/083782 (or US 2004/1 32880).

As coupling agent other than polysulfurized alkoxysilane, there may be mentioned in particular bifunctional POS (polyorganosiloxanes) or hydroxysilane polysulfides (R ₂₂ = OH in formula III above) as described in patent applications. WO 02/30939 (or US Pat. No. 6,774,255) and WO 02/31041 (or US 2004/05 1,210), or else silanes or POS bearing functional azodicarbonyl groups, as described, for example, in the applications of US Pat. WO 2006/1 25532, WO 2006/1 25533, WO 2006/25534.

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 es, 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 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 rate 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 tread of a tire.

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 comprises, as a primary vulcanization accelerator, one or more thiolefin compounds chosen from the compounds of formula (I) below:

(I)

in which

And R ₂ independently represent a hydrogen atom or a C 1 -C 2 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, Ri and R ₂ may together form a non-aromatic ring, but can not together form an aromatic ring, -A is selected from

a hydrogen atom;

- a group

in which

R ₃ , R ₅ and R ₅ independently represent a C 1 -C ₈ hydrocarbon-based group, optionally interrupted by one or more heteroatoms,

in which

R ₆ is a C 1 -C 18 hydrocarbon group optionally interrupted by one or more heteroatoms;

- a group

in which

R ₇ is a C 1 -C 12 hydrocarbon group _{; 8} , optionally interrupted by one or more heteroatoms; a group

in which

Y is a hydrocarbon chain C iC _18, optionally interrupted or substituted by one or more heteroatoms;

R ₈ is a hydrocarbon group-Ci _8, optionally interrupted by one or more heteroatoms; a group

in which

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-C15 hydrocarbon group, optionally interrupted by one or more heteroatoms, and a group

in which

Ru is a hydrogen atom or a hydrocarbon group in

Cj-Cie, optionally interrupted by one or more heteroatoms. The compounds of formula (I) may advantageously replace all or part of the accelerator compounds conventionally used.

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

By hydrocarbon group or chain (e) interrupted (c) by one or more heteroatoms means 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 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, R 1 and R ₂ independently represent a hydrogen atom or a methyl group.

According to a second embodiment, R 1 and R ₂ each represent a hydrogen atom.

According to a third embodiment, R 1 and R ₂ each represent a methyl group.

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

- the group

the group

and - the group

where y, R ₃ to R ₇ are as defined above.

R ₃ to R _JJ groups may be independently selected from linear, branched or cyclic, aryl groups, aralkyl groups and alkylaryl groups.

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

According to a particular embodiment, R ₃ , R and R ₅ represent a methyl group.

According to a particular embodiment, R ₆ represents a C 1 -C ₄ alkyl, more preferably 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 preferentially a C ₁ -C ₃ alkyl 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 R ₁₀ independently represent a lower alkyl group. C ₁ -C ₄ , more preferably a C 1 -C 3 alkyl and very preferably a methyl group or an ethyl group.

According to a particular embodiment, Ru represents a hydrogen atom.

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

The compound (s) of formula (I) 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 0.5 to 5 phr.

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

Π-4. Various additives

The rubber composition according to the invention may also comprise all or part of the usual additives conventionally used in elastomer compositions intended for the manufacture of tires, in particular treads, such as, for example, plasticizers or lubricating oils. extension, whether aromatic or non-aromatic, pigments, protective agents such as anti-ozone waxes (such as C32 ST Ozone wax), chemical antiozonants, anti-oxidants (such as 6-paraphenylenediamine), anti-fatigue agents, reinforcing resins, acceptors (for example phenolic novolak resin) or methylene donors (for example HMT or H3M) as described for example in 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 oils, esters (in particular trioleates) of glycerol, the hydrocarbon plasticizing resins 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, medium-useful assisting agents, in a known manner, by means of an improvement of the dispersion of the inorganic filler in the rubber matrix and a lowering of the viscosity of the compositions, to improve their ability to implement in the green state, these agents being for example hydrolysable silanes such as alkylalkoxysilanes (especially alkyltriethoxysilanes), polyols, polyethers (for example polyethylene glycols), primary, secondary or tertiary amines (for example trialkanol amines), hydroxylated or hydrolysable POSs, for example α, ω-dihydroxy-polyorganosiloxanes (especially α, ω-dihydroxy-polydimethylsiloxanes), fatty acids such as, for example, stearic acid. II-5. Fabricati on 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 a high temperature, up to a maximum temperature of between 110 ° C. and 190 ° C., preferably between 115 ° C. and 150 ° C. and more preferably still between 1 ° and 15 ° C. 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 110 ° C., for example between 40 ° C. and 100 ° C., phase in which the crosslinking or vulcanization system can be incorporated. 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, where appropriate, are intimately incorporated, by kneading, with the diene elastomer or the diene elastomers during the so-called non-productive first phase, that is to say that it is introduced into the mixer and kneaded. thermomechanically, in one or more steps, at least these different basic constituents until reaching the maximum temperature between 1 10 ° C and 190 ° C, preferably between 1 15 ° C and 1 50 ° 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 various additives, with the exception of the vulcanization system. The total mixing time, in this non-productive phase, is preferably between 1 and 15 min. 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 strip of tire rolling for passenger vehicle. II-6. Special thiazole compounds

The subject of the invention is also a thiazole compound of formula (Γ):

( ) in which

R i _a and R _2a independently represent a hydrogen atom 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 a or more heteroatoms, R _la and R _2a may together form a non-aromatic ring, but can not together form an aromatic ring,

-A _a is choi if among

a group

in which

R _3a , R _4a and R _{J a} independently represent a C 1 -C ₈ hydrocarbon group, optionally interrupted by one or more heteroatoms,

y _a is an integer greater than or equal to 1, preferably less than or equal to 1 0, more preferably less than or equal to 8 and most preferably less than or equal to 6, with the proviso that _the R and R _2a do not simultaneously denote a methyl or a hydrogen atom; aryl and hydrogen; a group

in which

R _6a is a C 1 -C 18 hydrocarbon group, optionally interrupted by one or more heteroatoms, chosen from linear, branched, cyclic, aralkyl, alkyl groups optionally substituted by one or more halogens, one or more linear or branched alkyl groups; linear or branched alkoxy, hydroxy, nitro,

and provided that R _a and R _2a independently denote a hydrogen atom or an alkyl group; a group

in which

R _7a is a C 1 -C 18 hydrocarbon group, optionally interrupted by one or more heteroatoms,

and provided that R _a and R _2a represent methyl respectively; a group

in which

X _a is a C1-C1 hydrocarbon chain, optionally interrupted or substituted by one or more heteroatoms, but which can not carry another phosphonate group,

R.9 and _has RIOA independently represent a hydrocarbon group-Cig, optionally interrupted by one or more heteroatoms, and

and with the proviso that R _a and R _2a independently represent a hydrogen atom or an alkyl group; and a group

in which

Riia is a hydrogen atom or a hydrocarbon group-Cig, provided that R _a and R _2a independently represent an alkyl group Ci-Cjg.

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, _the R and R _2a independently represent a hydrogen atom or a group rnéthyle.

According to a second embodiment, R] _a and R _2a each represents a hydrogen atom.

According to a third embodiment, _the R and R _2a each represents a rnéthyle group.

Advantageously, the thiazole compound of formula (Γ) is such that Aa is chosen from

- the group

the group the group

included _in R _3a to R _a being as defined above.

The groups R _3a to R 7 _a and R _a to R _lla may be independently selected from linear, branched or cyclic, aryl groups, aralkyl groups and alkaryl groups, subject to any conditions explained above for each of these groupings. The group X _may be independently selected from linear alkylene, branched or cyclic arylene groups and alkylarylene groups.

According to one particular embodiment, R _{3 a} , R ₄ _a and R _{5 a} represent a methyl group.

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

According to a particular embodiment, _X is an alkylene C 1 - C4 alkyl, more preferably a C ₁ -C 3 alkylene and very preferably a methylene group or an ethylene group and R _a and _Rio are independently alkyl C 1 -C 4, more preferably a C 1 -C 3 alkyl and very preferably a methyl group or an ethyl group.

IIiL Preparation of accelerators of general formula (Ij and m.

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

From thiols or thiolates described above and according to the nature of the group A or A _a, those skilled in the art can obtain the compounds of general formula (I) or (Γ) as shown below;

- When the radical A or A _has a group

^R 5 _or ^R 5a as defined above, the compound can be prepared by an oxidative coupling.

To a solution of the two precursor thiols 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 US2,196,607 (1940),

with (H ₄ ) 2S O in Stewart, Mathes, J. Org. Chem., 1949, vol.14, p. 1111 - 1117.

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

It is also possible to follow another procedure consisting of 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 carrying out a reaction in chloroform between a symmetrical disulfide and a mercaptan, for example tert-butyl mercaptan, which leads to a redistribution.

By this reaction, there is obtained the derivatives in which Y or Y _a = 1. For those compounds wherein y _or y is greater than 1, can be inserted sulfur atoms in the linking sulfur - existing sulfur, for example by reaction with triphenylthiosulfenyl chloride in dichloromethane in the presence of acetic acid, as proposed for example in Tetrahedron Letters, Volume 41, Issue 37, September 2000, Pages 7169-7172.

- When the radical n 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 ₆ or R (, _B.

For exampIe _s January Larsen and Christine Lenoir in Organic Synthesis, Coll. Flight. 9, p. 72 (1998) describe a thioesterification reaction between thiol and acid chloride in the presence of triethylamine to trap the hydrochloric acid formed, the reaction being carried out in dichloromethane at 0 to 10 ° C.

- When the radical A or A _has a group

as defined above, this compound may be prepared by elimination addition reaction between the thiol and an alkyl chloroformate carrying the radical R ₇ or R _7a which may itself be commercially available or prepared by reaction between a 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 (1975, 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; Endo, Katsuya in Heterocycles, 1 993, vol. 35, # 2 p. 895-900, The authors react sodium methylthiolate with methyl chloroformate to obtain the thiocarbonate derivative.

Another synthetic route is to react the thiol or its thiolate with phosgene (Chen, H.W. et al., Journal of the American Chemical Society 1978, vol. 1 00, p. 2370-2375) or a derivative thereof such as triphosgene (WO2008 / 0381 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 bearing the radicals Y and R _g such as, for example, bromoethylacetate or 4-bromomethylbutyrate.

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.K .; Bhalla, T.N. ; Shanker, K. in Bollettino Chimico Farmaceutico (1995), 134 (1), 9-15.

- When the radical A or A _has a group

0¾ OR ,,

- X - ^ - OR ₁₀ - X- ^ OR _10a

⁰ or ⁰

as defined above, this compound can be prepared by nucleophilic substitution between the thiol or thiolate and a halogenated derivative of a phosphonate or phosphonic acid bearing the radicals X, R 9 and io or X _a, R _a and R oa 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 rethanethiolate in an ether (Mikolajczyk, Mari, Costisella, Burkhard, Grzej szczak, Slawomir, Tetrahedron, 1983, vol 39 # 7, pp. 89-1,193).

- When the radical A or A _has a group

as defined above, this compound may be prepared by nucleophilic substitution between the thiol or its thiolate and an allyl halide carrying the radical Rn or R u, and for example between the thiol and allyl bromide.

For example, the reaction between a triazinc thiol and an allyl halide in the presence of potassium hydroxide in alcohol is described in patent BE 503980 of the Belgian Society of Nitrogen and Chemicals Mari y (1 95 1). .

An example of a compound of formula (I) is 2-mercaptothiazol of the following formula (1):

(1)

marketed for example by ABCR.

III. Examples

A. Examples of compound synthesis

1. Synthesis of compound A: diethyl 2- (4,5-dimethylthiazol-2-ylthio) ethylphosphonate Compound A is synthesized according to the reaction scheme

To a solution of 4,5-dimethylthiazole-2-thiol (300 g, 0.021 mol) in 30 mL of acetone is added, all at once, ₂ CO ₃ (2.85 g, 0.021 mol, Aldri ch > 99%). The reaction medium is stirred at a temperature between 40 and 45 ° C. After stirring for 20 minutes, diethyl 2-bromoethylphosphonate (5.00 g, 0.020 mol, Aldrich, 97%) is added over a period of 3 minutes. The reaction mixture is stirred for 1 hour under reflux and is then cooled slowly (2 hours) to room temperature.

The precipitate formed of the residual salts is filtered and washed on the filter with 5 ml of acetone. The filtrate is concentrated under reduced pressure (5-6 mbar, 23 ° C.) to obtain a constant mass.

A brown oil (5.382 g, 0.01 7 mol, 84% yield) is obtained.

The molar purity is greater than 93% (NMR ¹ )

TLC: R, = 0.5 (Si0 ₂ , EtOAc, UV and I ₂ revelation).

NMR characterization of the product obtained: The chemical shifts obtained by ¹³ C NMR and ¹³ C in DMSO-d6 are given in the table below. The calibration is performed on DMSO (2.44 ppm in 1H, 39.5 ppm in ¹³ C and calibration ^3, P with sr = 0, sr: spectrum reference).

2. Synthesis of compound B: 4,5-dimethylthiazol-2-yl propanethioate

Compound B is synthesized according to the following reaction scheme:

To a solution of 4,5-dimethylthiazole-2-thiol (14.5 g, 0.100 ol) and triethylamine (11.11 g, 0.110 mol) in cyclohexane (400 g) mL) is added a solution of propionyl chloride (9.24 g, 0.100 mol) in cyclohexane (60 mL) at 5 ° C over a period of 15 minutes. The temperature of the reaction medium is brought slowly (2 hours) to 23 ° C. The reaction medium is then stirred for 2.0-2.5 hours at this ambient temperature. The triethylamine hydrochloride Et ₃ N'HCl is filtered through Celite® and washed on the filter with petroleum ether (3 times per 50 ml, fraction 40/60 ° C.). The filtrate is washed with water (3 times per 50 ml). The organic phases are separated, combined and then concentrated under reduced pressure (3-4 mbar, 32 ° C.) to give 17.93 g of crude reaction product.

The reaction crude is dissolved in petroleum ether (500 mL) and this solution is washed with a solution of triethylamine (3.0 g, 0.030 mol) in water (150 mL). The biphasic mixture is stirred vigorously for 2 hours at room temperature. The organic phase is separated and washed with water (3 x 50 mL). The separated and combined organic phases are concentrated under reduced pressure (32 ° C., 3-4 mbar).

A liquid (light yellow) (16.1 g, 0.080 mol, 80% yield) is obtained.

The molar purity is greater than 93% (NMR ^ι Ή.) "

TLC: R _f - 0.61 (SiO ₂ , heptane: EtOAc - 1: 1, revealing by UV and I ₂ ).

NMR characterization of the product obtained

The chemical shifts obtained by NMR ^! H and ¹ C in chloroform-d are given in the table below. Calibration is carried out on chloroform 7.2 ppm ^. H and 77 ppm in ¹³ C).

3. Synthesis of Compound C: Ethyl 2- (4,5-dimethylthiazol-2-ylthio) acetate

Compound C is synthesized according to the following reaction scheme:

To a solution of 4,5-dimethylthiazole-2-thiol (10.53 g, 0.073 mol) in acetone (400 mL) is added, one time, K ₂ CO ₃ (1 0.50 g, 0.076 g). mol). The reaction mixture is stirred and then ethyl chloro-formate (8.89 g, 0.073 mol) is added dropwise. The reaction medium is refluxed for 2.5 hours. The medium is then cooled to 20 ° C. The reaction medium is filtered and the filtrate is concentrated under reduced pressure to give an oil (15.384 g, 0.067 mol, 92% yield).

The molar purity is greater than 96% (NMR ^J H). TLC: R _f = 0.8 (SiO ₂ , cyclohexane: EtOAc = 1: 1, revealing by UV and I ₂ ).

NMR characterization:

The chemical shifts obtained by NMR ^! H and ¹³ C in d-acetone are given in the table below. The calibration is carried out on DMSO (1.98 ppm in 1H and 29.8 ppm in ¹³ C).

4. Synthesis of Compound D: 2- (Allvlthio1-4.5-dimethylthiazole Compound D is synthesized according to the reaction scheme

To a solution of 4,5-dimethylthiazole-2-thiol (1100 g, 0.075 mol) in 160 ml of acetone is added, at once, K ₂ CO ₃ (10.00 g, 0.072 mol). , Aldrich,> 99%). The reaction medium is stirred for 20 minutes at a temperature between 40 and 45 ° C. Then, allyl bromide (1100 g, 0.090 mol, Acros, 99%) is added over a period of 2 minutes. The reaction mixture is stirred for one hour under reflux and then cooled slowly (1 hour) to room temperature.

The precipitate is filtered on the filter with 10 ml of acetone. The filtrate was concentrated under reduced pressure (9- 1 0 mbar, 24 ° C) ^until obtaining a constant weight.

A brown oil (12.22 g, 0.066 mol, yield 87%) is obtained.

The molar purity is greater than 97% (NMR ^l). NMR characterization:

The chemical shifts obtained by NMR ^! H and ¹³ C in DMSO-6 are given in the table below. Calibration is performed on DMSO (2.44 ppm in ¹ H and 39.5 ppm in ¹³ C).

5. Synthesis of compound E: O-benzyl-4,5-dimethylthiazol-2-yl carbonothioate

Compound E is synthesized according to the following reaction scheme:

To a solution of 4,5-dimethylthiazole-2-thiol (10.041 g, 0.069 mol) in acetone (370 mL) is added, one time, K2CO3 (11.480 g, 0.083 mol). The reaction mixture is stirred and benzyl chloroformate (11.810 g, 0.069 mol) is added dropwise. The reaction medium is refluxed for 3.5 hours. The medium is then cooled to 20 ° C and filtered. The filtrate is concentrated under reduced pressure (9-10 mbar, -35 ° C). The resulting solid was recrystallized from 150 mL of ethanol to provide a white solid (14.695 g, 0.053 mol, 76% yield) mp 72-73 ° C.

The molar purity is greater than 99% ( ¹ H NMR).

NMR characterization: The chemical shifts obtained by ¹³ C NMR and ¹³ C in DMSO-d6 are given in the table below. Calibration is performed on DMSO (2.44 ppm in 1H and 39.5 ppm in ¹³ C).

6. Synthesis of compound F: 2- (N-Butyldisulfanyl) -4-dimethylthiazole Compound F is synthesized according to the following reaction scheme:

To a solution 2-methyl-2-propanethiol (6.3 1 g, 0.070 mol) and 4,5-dimethylthiazole-2-thiol (10, 17 g, 0.070 mol) in ethanol (60 mL) is added dropwise a solution of H ₂ 0 ₂ (9.0 mL, 0.080 mol 30% in water) over a period of 50 minutes so that the temperature of the reaction medium is less than 3 1 ° vs. The reaction medium is refluxed and stirred for 3.0 hours. After returning to ambient temperature, the reaction medium is diluted with heptane (200 mL) and the solution is then washed with water (4 times on 50 mL). The aqueous phase is washed with heptane (4 times on 25 ml). The combined organic phases are washed with water (twice with 50 ml), dried over sodium sulphate, filtered and concentrated under reduced pressure (Tbain 35 ° C., 7 mbar).

A solid (15.85 g, 0.068 mol, 97% yield) with a melting point of 31 ° C. is obtained.

The molecular purity is greater than 99% (1H NMR).

TLC: R _f = 0.78 (SiO ₂ , heptanc: EtOAc - 1: 1, revealing by UV and I ₂ ). NMR characterization

The chemical shifts obtained by H and C NMR in DMSO-6 are given in the table below. Calibration is éalisée of DMSO (in ^2,44ppm! H and 39.5 ^{ppm, 3} C).

B. Examples of compositions 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 vulcanization (composition C 1), with the properties of a rubber composition according to the invention comprising compound F (composition C2), compound B (composition C3) or compound E (composition C4) as primary accelerator vulcanization.

The formulations of the compositions are given in the table

1 below. The amounts are expressed in parts per 100 parts by weight of clastomer (phr).

Table 1

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

(2) butadiene-styrene copolymer SSBR (SBR prepared in solution) with 25% styrene, 59% polybutadiene units 1 -2 and

20% of trans-4 polybutadiene units (Tg = -24 ° C.), (mol%); 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: about 160 m2 / g);

(5) Antioxidant agent 6-para-phenylenediamine

(6) Antiozonant agent

(7) Aliphatic resin (pure C5) "Hikorez A-1 100" marketed by the company KOLON

(8) coupling agent

(9) Stearin "Pristeren" from the company Uniquema

(10) Diphenylguanidine (Perkacit DPG from Flexsys)

* MBTS of the company G-QUIMICA commerciali se under the reference 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 the compounds F, B and E can be used as a vulcanization accelerator in rubber compositions comprising one or more reinforcing fillers.

Example 2

The purpose of this example is to compare the properties of a rubber composition comprising carbon black, usable for the manufacture of a tire tread, including the MBTS as a primary vulcanization accelerator (composition C l), with the properties of a rubber composition according to the invention comprising compound F (composition C2), compound B (composition C3) or compound E (composition C4) as a primary vulcanization accelerator.

The formulations of the compositions are given in the table

3 below. Quantities are expressed in parts per 100 parts by weight of elastomer (phr).

Table 3

(1) natural rubber

(2) Stearin "Pristeren" of the company Uniqucma

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

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

Table 4

The rheometric properties obtained for the compositions according to the invention show that compounds F, B and E can be used as a vulcanization accelerator in rubber compositions comprising one or more reinforcing fillers.

Claims

1. 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 thiazole compounds selected from the compounds of formula (I) below:

(I)

in which

R i and R ₂ independently represent a hydrogen atom 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, Ri and R ₂ may together form a non-aromatic cycl e, but can not together form an aromatic ring,

-A is selected from

a hydrogen atom,

- a group

in which R ₃ , R ₄ and Rs independently represent a C ₁ -C ₁₂ hydrocarbon group, optionally interrupted by one or more heteroatoms,

in which

R6 is a C1-C1 hydrocarbon group, optionally interrupted by one or more heteroatoms; a group

in which

R ₇ is a C 1 -C 8 hydrocarbon group, optionally interrupted by one or more heteroatoms;

- a group

in which

Y is a C1-C4 hydrocarbon chain, optionally interrupted or substituted by one or more heteroatoms, R8 is a C1-C18 hydrocarbon group, optionally interrupted by one or more heteroatoms; a group

in which

X is a C ₁ -C ₁₈ hydrocarbon-based chain, optionally interrupted or substituted by one or more heteroatoms,

R ₉ and R o are independently a hydrocarbon group ₁ -C _8, optionally interrupted by one or clea ers heteroatoms, and a group

in which

R i i is a hydrogen atom or a C 1 -C 18 hydrocarbon group, optionally interrupted by one or more heteroatoms.

2. Composition according to claim 1, characterized in that

R 1 and R 2 independently represent a hydrogen atom or a methyl group.

3. Composition according to claim 2, characterized in that R 1 and R ₂ each represent a hydrogen atom.

4. Composition according to claim 2, characterized in that

R i and R ₂ each represent a methyl group.

5. Composition according to any one of the preceding claims, characterized in that A is chosen from

- the group

and

- the group

where y, R 3 to R ₇ are as defined in claim 1.

6. 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.

7. 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, arylene groups and alkylarylene groups.

8. Composition according to any one of the preceding claims, characterized in that the said thiazole 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).

9. Composition according to any one of the preceding claims, characterized in that the diene elastomer or elastomers are chosen from the group consisting of polybutadienes, natural rubber, synthetic polyisoprenes, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

10. Composition according to any one of the preceding claims, characterized in that the reinforcing fillers or fillers are chosen from silica, carbon black and mixtures thereof, preferably carbon black.

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

12. 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 a diene elastomer, during a first step, the reinforcing fillers or by thermomechanically kneading the whole, in one or more times, to reach a maximum temperature between 1 10 ° C and 1 90 ° VS ;

- Then incorporate, during a second step, the crosslinking system and knead the whole to a maximum temperature below 1 10 ° C.

13. The method of claim 12, wherein between the thermomechanical mixing and the incorporation of the crosslinking system, is carried out cooling the assembly at a temperature less than or equal to 100 ° C.

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

5. A finished article or semi-finished product for a motor vehicle ground system, comprising a composition as defined in any one of claims 1 to 11.

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

Tread comprising a rubber composition as defined in any one of claims 1 to 11.

8. Utilization 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 thiazole compounds of formula (I) such as: as defined in any one of claims 1 to 7.

1 9. Thiazole of formula (Γ) below:

( ) in which

R ia and R _2a independently represent a hydrogen atom 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 several heteroatoms, R _la and R _2a may together form a non-aromatic ring, but can not together form an aromatic ring,

-A _a is selected from

- a group

in which R _3a , R _4a and R _5a independently represent a C 1 -C 18 hydrocarbon group, optionally interrupted by one or more heteroatoms,

with the proviso that R _a and R _2a do not simultaneously denote a methyl or a hydrogen atom; or an aryl and a hydrogen atom; a group

in which

R _6a is a C 1 -C ₈ hydrocarbon-based group, optionally interrupted by one or more heteroatoms, chosen from linear, branched, cyclic, aralkyl alkyl groups, optionally substituted by one or more halogen, one or more linear or branched alkyl groups; linear or branched alkoxy, hydroxy, nitro,

and with the proviso that and R _2a independently denote a hydrogen atom or an alkyl group; a group

in which

and with the proviso that R _{1 B} and R _2a respectively represent a methyl; a group

OR _9a

in which

X _a is a C1-C hydrocarbon chain, optionally interrupted or substituted by one or more heteroatom es, but which can not carry another phosphonate group,

R _9a Ei _Rio independently represent a hydrocarbon group of C i -C jg, optionally interrupted by one. or more heteroatoms, and

and provided that R _a and R _2a independently represent a hydrogen atom or an alkyl group and a. group

in which

Ru is a hydrogen atom or a hydrocarbon group of C i -C ig, provided that R _a and R _2a independently represent an alkyl group Ci-C ie.

20. Thiazole according to claim 19, characterized in that R 1 and R _2a independently represent a hydrogen atom or a methyl group.

21. Thiazole according to claim 20, characterized in that

_The R and R _2a each represents a hydrogen atom.

22. Thiazole according to claim 20, characterized in that Ri _a and R _2a each represent a methyl group.

23. Thiazole according to any one of claims 19 to 22, characterized in that Aa is chosen from the group

the group the group

included _in R _3a to R _7a being such s as defined in claim 1. 9

24. Thiazole according to any one of claims 1 to 23, characterized in that the groups R _3a to R _7a and R _9a to Rn _a are independently selected from linear, branched or cyclic alkyl groups, aryl groups, aralkyl groups and alkylaryl groups.

25. Thiazole according to any one of Claims 1 to 24, characterized in that the group X _a is chosen from linear, branched or cyclic alkylene groups, arylene groups and alkylarylene groups.