Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
  • C08L25/02—Homopolymers or copolymers of hydrocarbons
  • C08L25/04—Homopolymers or copolymers of styrene
  • C08L25/08—Copolymers of styrene
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
  • B60C1/0016—Compositions of the tread
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L53/00—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
  • Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction 

Definitions

• the present invention relates to tire treads and rubber compositions based on diene elastomers and saturated styrenic thermoplastic elastomers used in the manufacture of such tire treads.
• a tire must obey in a known manner a large number of technical requirements, often antithetical, among which a high wear resistance, a low rolling resistance, a high grip on dry and wet road and a good road behavior (" handling ") on a motor vehicle. This compromise of properties, in particular from the point of view of rolling resistance and wear resistance, has been improved in recent years on "green tires” with low energy consumption, especially for passenger vehicles.
• a tire tread comprising a specific rubber composition, based on a polybutadiene and a saturated TPS copolymer, which makes it possible to improve the rigidity and therefore the road behavior of the tires. without penalizing the hysteresis.
• a first object of the invention relates to a tire comprising a tread comprising an elastomer composition, said composition comprising: from 10 to 60 phr of a polybutadiene elastomer (BR);
• BR polybutadiene elastomer
• TPS thermoplastic styrene elastomer
• the tires of the invention are particularly intended for equipping tourism-type motor vehicles, SUVs ("Sport Utility Vehicles"), two wheels (in particular motorcycles), aircraft, such as industrial vehicles chosen from light trucks and "heavy trucks”. , ie metro, bus, road transport equipment (trucks, tractors, trailers), off-the-road vehicles such as agricultural or civil engineering machinery, other transport or handling vehicles.
• the rubber compositions used in the tires according to the invention are characterized, before and after firing, as indicated below.
• the Shore A hardness of the compositions after firing is assessed according to ASTM D 2240-86.
• Dynamic properties are measured on a viscoanalyzer (Metravib VA4000) according to ASTM D 5992-96.
• the response of a composition sample is recorded vulcanized (cylindrical specimen 4 mm thick and 400 mm 2 in section), subjected to a sinusoidal stress in alternating simple shear, at the frequency of 10 Hz, during a temperature sweep, under a fixed stress of 0, 7 MPa, the value of tan ( ⁇ ) observed at 40 ° C. (tan ( ⁇ ) 40 ° C.) is recorded.
• tan ( ⁇ ) 40 ° c is representative of the hysteresis of the material and therefore of the rolling resistance: plus tan ( ⁇ ) 40 ° c is low the higher the rolling resistance is reduced.
• the tire according to the invention which comprises a tread comprising an elastomer composition comprising at least:
• BR polybutadiene elastomer
• TPS saturated thermoplastic styrene elastomer
• 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 (i.e. terminals a and b excluded) while any range of values designated by the term “from a to b” means the range from a to b (i.e., including the strict limits a and b).
• elastomer (or “rubber”, both of which are considered synonymous) of the "diene” type, it will be recalled here that an elastomer derived at least in part (ie, a homopolymer or a copolymer) from a known manner must be understood. monomers dienes (monomers bearing two carbon-carbon double bonds, conjugated or otherwise).
• the polybutadiene content is preferably within a range of 20 to 55 phr.
• 1,3-butadiene, 2-methyl-1,3-butadiene and 2,3-di (C 1 -C 5) alkyl-1,3-butadienes such as for example 2-butadiene
• 2-butadiene 1,3-butadiene, 2-methyl-1,3-butadiene and 2,3-di (C 1 -C 5) alkyl-1,3-butadienes, such as for example 2-butadiene
• BR 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%, more preferably greater than 90% .
• the elastomer BR is the only diene elastomer present in the composition.
• the rubber composition of the tread of the tire according to the invention may comprise a second diene elastomer whose level is preferably between 0 and 80 phr, more preferably in a range of 5 to 60 pce.
• the second diene elastomer is selected from the group consisting of styrene-butadiene copolymers (SBR), natural rubber (NR), synthetic polyisoprenes (IR), isoprene-styrene copolymers (SIR), isoprene copolymers butadiene (BIR), styrene-butadiene-isoprene terpolymers (SBIR) and mixtures of these elastomers.
• SBR styrene-butadiene copolymers
• NR natural rubber
• IR synthetic polyisoprenes
• SIR isoprene-styrene copolymers
• BIR isoprene copolymers butadiene
• SBIR styrene-butadiene-isoprene terpolymers
• the second diene elastomer is an SBR elastomer.
• the SBR copolymers may for example be block, random, block, microsequential, and be prepared in dispersion or in solution; they can be coupled and / or star or functionalized with a coupling agent and / or starring or functionalization.
• functional groups comprising a C-Sn bond or amino functional groups such as benzophenone for example
• silanol or polysiloxane functional groups having a silanol end as described, for example, in US Pat. No.
• alkoxysilane groups as described, for example, in US 5,977,238), carboxylic groups (as described, for example, in US 6,815,473 or US 2006/0089445) or polyether groups (as described for example in US 6,503,973).
• the SBR elastomer may be an emulsion-prepared SBR ("ESBR") or a solution-prepared SBR ("SSBR").
• ESBR emulsion-prepared SBR
• SSBR solution-prepared SBR
• an SBR elastomer ESBR or SSBR
• particular use is made of an SBR having an average styrene content, for example between 20% and 35% by weight, or a high styrene content, for example from 35 to 45%, a vinyl bond 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 °.
• the tire according to the invention comprises a rubber composition which has another essential feature of comprising a saturated TPS elastomer in an amount of 10 to 60 phr, preferably 15 to 55 phr. Below 10 phr, the rigidity of the composition is not sufficiently improved, beyond 60 phr, the hysteresis may be penalized.
• Styrenic thermoplastic elastomers are thermoplastic elastomers in the form of styrene-based block copolymers.
• thermoplastic polymers and elastomers consist in a known manner of rigid polystyrene blocks connected by flexible elastomer blocks, for example polybutadiene, polyisoprene or poly (ethylene / butylene). They are often triblock elastomers with two rigid segments connected by a flexible segment. The rigid and flexible segments can be arranged linearly, star or connected. These TPS elastomers may also be diblock elastomers with a single rigid segment connected to a flexible segment.
• each of these segments or blocks contains at least more than 5, usually more than 10 base units (e.g., styrene units and isoprene units for a styrene / isoprene / styrene block copolymer).
• base units e.g., styrene units and isoprene units for a styrene / isoprene / styrene block copolymer.
• saturated TPS elastomer a TPS elastomer which does not contain any ethylenic unsaturation (i.e., no carbon-carbon double bond);
• TPS elastomer unsaturated TPS elastomer
• TPS elastomer which is provided with ethylenic unsaturations, that is to say which has carbon-to-carbon double bonds
• the saturated TPS copolymer is a copolymer comprising styrene blocks and alkylene blocks.
• the alkylene blocks are preferably ethylene, propylene or butylene.
• the saturated TPS elastomer is selected from the group consisting of styrene / ethylene / butylene (SEB), styrene / ethylene / propylene (SEP), styrene / ethylene / ethylene / propylene (SEEP), styrene / ethylene block copolymers / butylene / styrene (SEBS), styrene / ethylene / propylene / styrene (SEPS), styrene / ethylene / ethylene / propylene / styrene (SEEPS) and mixtures of these copolymers.
• SEB styrene / ethylene / butylene
• SEP styrene / ethylene / propylene
• SEEP styrene / ethylene block copolymers / butylene / styrene
• SEBS s
• said elastomer is selected from the group consisting of SEBS copolymers, SEPS copolymers, SEEPS copolymers and mixtures of these copolymers.
• the styrene levels of the saturated TPS elastomer is between 5 and 50%. Below the minimum indicated, the thermoplastic nature of the elastomer may decrease significantly while above the maximum recommended, the elasticity of the composition may be affected. For these reasons, the styrene content is more preferably between 10 and 40%, in particular between 15 and 35%.
• the number-average molecular weight (denoted Mn) of the saturated TPS elastomer is preferably between 50,000 and 500,000 g / mol, more preferably between 75,000 and 450,000, especially for use of the composition in a strip of tire rolling. The molecular weight Mn is determined in known manner, by steric exclusion chromatography (SEC).
• the sample is first solubilized in tetrahydrofuran at a concentration of about 1 g / l; then the solution is filtered on a 0.45 ⁇ m porosity filter before injection.
• the equipment used is a chromatographic chain "WATERS alliance”.
• the elution solvent is tetrahydrofuran, the flow rate 0.7 ml / min, the system temperature 35 ° C and the analysis time 90 min.
• a set of four WATERS columns in series, of trade names "STYRAGEL" ("HMW7", “HMW6E” and two "HT6E" is used.
• the injected volume of the solution of the polymer sample is 100 ⁇ l.
• the detector is a differential refractometer "WATERS 2410" and its associated software for the exploitation of chromatographic data is the “WATERS MILLENIUM” system.
• the calculated average molar masses relate to a calibration curve made with polystyrene standards.
• reinforcing filler 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.
• an organic filler such as carbon black
• a reinforcing inorganic filler such as silica
• 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).
• the reinforcing carbon blacks of the 100, 200 or 300 series for example blacks Nl 15, N134, N234, N326, N330, N339, N347 or 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 an isoprene elastomer in the form of a masterbatch (see for example WO 97/36724 or WO 99/16600).
• organic fillers other than carbon blacks mention may be made of functionalized polyvinyl organic fillers as described in applications WO-A-2006/069792, WO-A-2006/069793, WO-A-2008/003434 and WO-A-2008/003435.
• any inorganic or mineral filler (whatever its color and its natural or synthetic origin), also called “white” filler, “clear” filler or “non-black filler”, as opposed to carbon black, capable of reinforcing on its own, without any other means than an intermediate coupling agent, a rubber composition intended for the manufacture of tires, in other words capable of replacing, in its reinforcing function, a conventional carbon black of pneumatic grade; such a filler is generally characterized, in known manner, by the presence of hydroxyl groups (-OH) on its surface.
• -OH hydroxyl groups
• reinforcing inorganic filler is present indifferent, whether in the form of powder, microbeads, granules, beads or any other suitable densified form.
• 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, 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, especially any precipitated or fumed silica having a BET surface and a CTAB specific surface both less than 450 m 2 / g, preferably 30 to 400 m 2 / g.
• HDS highly dispersible precipitated silicas
• the Ultrasil 7000 and Ultrasil 7005 silicas from Degussa the Zeosil 1165MP, 1135MP and 1115MP silicas from Rhodia
• the Hi-SiI silica EZ150G from the PPG company
• the Zeopol 8715, 8745 and 8755 silicas of the Huber Company the high surface area silicas as described in the application WO 03/16837.
• the reinforcing inorganic filler used in particular if it is silica, preferably has a BET surface area of between 45 and 400 m 2 / g, more preferably between 60 and 300 m 2 / g.
• 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 goods vehicles.
• a reinforcing filler comprising 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).
• an at least bifunctional coupling 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.
• 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).
• symmetrical polysulfide silanes having the following general formula (I):
• the radicals R 1 substituted or unsubstituted, which are identical to or different from one another, represent a C 1 -C 18 alkyl, C 5 -C 18 cycloalkyl or C 6 -C 18 aryl group (preferably C 1 -C 8 alkyl groups); 6 , cyclohexyl or phenyl, especially C 1 -C 4 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 18 cycloalkoxyl group (preferably a group chosen from C 1 -C 8 alkoxyls and C 5 -C 8 cycloalkoxyls); Cs, more preferably still a group selected from C 1 -C 4 alkoxyls, in particular methoxyl and ethoxyl).
• the average value of "x" is a fractional number preferably of between 2 and 5, more preferably close to 4.
• polysulphurized silanes mention may be made more particularly of the polysulfides (in particular disulfides, trisulphides or tetrasulfides) of bis (C 1 -C 4 alkoxy) alkyl (C 1 -C 4 ) silyl-alkyl (C 1 -C 4 ).
• TESPT bis (3-triethoxysilylpropyl) tetrasulfide
• TESPD bis (3-triethoxysilylpropyl) tetrasulfide
• TESPD bis (3-triethoxysilylpropyl) tetrasulfide
• WO 02/30939 or US 6,774,255
• WO 02/31041 or US 2004/051210
• silanes or POS bearing azo-dicarbonyl functional groups as described for example in patent applications WO 2006/125532, WO 2006/125533, WO 2006/125534.
• the content of coupling agent is preferably between 4 and 12 phr, more preferably between 4 and 8 phr.
• the tread rubber compositions of the tires according to the invention also comprise all or part of the usual additives normally used in elastomer compositions intended for the production of treads, such as, for example, pigments, protective agents such as anti-ozone waxes, chemical antiozonants, anti-oxidants, other plasticizing agents than those mentioned above, anti-fatigue agents, reinforcing resins, acceptors (for example phenolic novolac resin) or methylene donors (for example HMT or H3M), a crosslinking system based on either sulfur, or sulfur and / or peroxide donors and / or bismaleimides, vulcanization accelerators, vulcanization activators.
• additives normally used in elastomer compositions intended for the production of treads such as, for example, pigments, protective agents such as anti-ozone waxes, chemical antiozonants, anti-oxidants, other plasticizing agents than those mentioned above, anti-fatigue agents, reinforcing resins, acceptors (for example phenolic novo
• compositions may also contain, in addition to the coupling agents, coupling activators, inorganic charge-covering agents or, more generally, processing aids that can be used in a known manner, thanks to an improvement in the dispersion. of the charge in the rubber matrix and a lowering of the viscosity of the compositions, to improve their ability to use in the green state, these agents being for example hydrolysable silanes such as alkylalkoxysilanes, polyols, polyethers, primary, secondary or tertiary amines, hydroxyl or hydrolyzable polyorganosiloxanes.
• hydrolysable silanes such as alkylalkoxysilanes, polyols, polyethers, primary, secondary or tertiary amines, hydroxyl or hydrolyzable polyorganosiloxanes.
• the treads of the tires according to the invention further comprise rubber compositions which comprise a plasticizer.
• this plasticizer is a solid hydrocarbon resin, a liquid plasticizer, or a mixture of both.
• the level of plasticizer is preferably between 5 and 50 phr, more preferably between 10 and 40 phr, for example between 15 and 35 phr.
• this plasticizer is a hydrocarbon resin whose Tg is greater than 0 0 C, preferably greater than + 20 0 C.
• the term "resin” is reserved in the present application, by definition, to a compound which is a solid at room temperature (23 ° C.) (as opposed to a liquid plasticizer such as 'an oil).
• the plasticizing hydrocarbon resin has at least one of the following characteristics:
• Tg greater than 20 0 C, more preferably greater than 30 0 C;
• Mn a number-average molecular mass (Mn) of between 400 and 2000 g / mol, more preferentially between 500 and 1500 g / mol;
• this plasticizing hydrocarbon resin has all of the above preferred characteristics.
• the macrostructure (Mw, Mn and Ip) of the hydrocarbon resin is determined by steric exclusion chromatography (SEC): solvent tetrahydrofuran; temperature 35 ° C; concentration 1 g / 1; flow rate 1 ml / min; filtered solution on 0.45 ⁇ m porosity filter before injection; Moore calibration with polystyrene standards; set of 3 "WATERS” columns in series (“STYRAGEL” HR4E, HR1 and HR0.5); differential refractometer detection (“WATERS 2410") and its associated operating software (“WATERS EMPOWER”).
• SEC steric exclusion chromatography
• the hydrocarbon resins may be aliphatic or aromatic or alternatively of the aliphatic / aromatic type, that is to say based on aliphatic and / or aromatic monomers. They may be natural or synthetic, whether or not based on petroleum (if so, also known as petroleum resins).
• the plasticizing hydrocarbon resin is chosen from the group consisting of homopolymer or copolymer resins of cyclopentadiene (abbreviated as CPD) or dicyclopentadiene (abbreviated as DCPD), terpene homopolymer or copolymer resins, homopolymer resins or terpene phenol copolymer, C5 homopolymer or copolymer resins, C9 homopolymer or copolymer resins and mixtures of these resins.
• CPD cyclopentadiene
• DCPD dicyclopentadiene
• terpene homopolymer or copolymer resins homopolymer resins or terpene phenol copolymer
• C5 homopolymer or copolymer resins C9 homopolymer or copolymer resins and mixtures of these resins.
• pene here combines in a known manner the alpha-pinene, beta-pinene and limonene monomers; preferably, a limonene monomer is used which is present in a known manner in the form of three possible isomers: L-limonene (laevorotatory enantiomer), D-limonene (dextrorotatory enantiomer), or the dipentene, racemic of the dextrorotatory and levorotatory enantiomers. .
• hydrocarbon plasticizing resins mention may be made especially of homo- or copolymer resins of alphapinene, betapinene, dipentene or polylimonene, C5 homopolymer or copolymer resins, homopolymer resins or copolymer cutting. C9 and mixtures of these resins, used alone or in combination with a liquid plasticizer for example an oil, such as MES or TDAE.
• a liquid plasticizer for example an oil, such as MES or TDAE.
• Suitable aromatic monomers are, for example, styrene, alpha-methylstyrene, ortho-, meta-, para-methylstyrene, vinyl-toluene, para-tertiobutylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene and divinylbenzene.
• vinylnaphthalene any vinyl aromatic monomer from a C 9 fraction (or more generally a sectional Cs -C 10).
• the vinylaromatic monomer is styrene or a vinyl aromatic monomer from a C 9 fraction (or more generally a sectional Cs -C 10).
• the vinylaromatic monomer is the minor monomer, expressed as a mole fraction, in the copolymer under consideration.
• preferred resins there may be mentioned in particular phenol-modified alpha-methylstyrene resins. To characterize these phenol-modified resins, it is recalled that a so-called "hydroxyl number" index (measured according to ISO 4326 and expressed in mg KOH / g) is used in a known manner.
• C 5 / vinylaromatic copolymer resins in particular C 5 / styrene or C 5 / C 9 cuts: by Neville Chemical Company under the names "Super Nevtac 78", “Super Nevtac 85” or “Super Nevtac 99", by Goodyear Chemicals under the name “Wingtack Extra”, by Kolon under the names "Hikorez T1095" and “Hikorez Tl 100”, by Exxon under the names "Escorez 2101" and "ECR 373";
• the plasticizer is a liquid plasticizer at 20 0 C, said to "low Tg", that is to say which by definition has a Tg lower than -20 0 C, preferably, preferably less than -40 ° C.
• Any extender oil whether of aromatic or non-aromatic nature, any liquid plasticizer known for its plasticizing properties with respect to diene elastomers, can be used.
• Particularly suitable liquid plasticizers selected from the group consisting of naphthenic oils, including hydrogenated oils, paraffinic oils, MES oils, TDAE oils, ester plasticizers, ethers, plasticizers phosphates and sulfonates and mixtures of these compounds.
• compositions used in the treads of the tires of the invention may be manufactured in appropriate mixers, using two successive preparation phases well known to those skilled in the art: a first phase of work or thermomechanical mixing (phase called “nonproductive”) at a high temperature, up to a maximum temperature of between 110 ° C. and 190 ° C., preferably between 130 ° C. and 180 ° C., followed by a second mechanical working phase (“phase” productive ”) until a lower temperature, typically less than 110 0 C, for example between 40 0 C and 100 0 C, finishing phase during which the crosslinking system is incorporated.
• a first phase of work or thermomechanical mixing phase called “nonproductive” at a high temperature, up to a maximum temperature of between 110 ° C. and 190 ° C., preferably between 130 ° C. and 180 ° C.
• phase second mechanical working phase
• finishing phase finishing phase during which the crosslinking system is incorporated.
• compositions comprising for example the following steps:
• the non-productive phase is conducted in a single thermomechanical step during which is introduced into a suitable mixer such as a mixer internal standard, initially all the necessary basic constituents (from 10 to 60 phr of polybutadiene, 10 to 60 phr of saturated thermoplastic styrene copolymer, the reinforcing filler), then in a second time, for example after one to two mixing minutes, the other additives, any additional load-collecting or processing agents, with the exception of the crosslinking system.
• the total mixing time in this non-productive phase is preferably between 1 and 15 minutes.
• the mixture thus obtained After cooling the mixture thus obtained, it is then incorporated in an external mixer such as a roll mill, maintained at low temperature (for example between 40 0 C and 100 0 C), the crosslinking system. The whole is then mixed (productive phase) for a few minutes, for example between 2 and 15 min.
• an external mixer such as a roll mill, maintained at low temperature (for example between 40 0 C and 100 0 C), the crosslinking system.
• the whole is then mixed (productive phase) for a few minutes, for example between 2 and 15 min.
• the actual crosslinking system is preferably based on sulfur and a primary vulcanization accelerator, in particular a sulfenamide type accelerator.
• vulcanization activators such as zinc oxide, stearic acid, guanidine derivatives (especially diphenylguanidine), etc.
• the sulfur content is preferably between 0.5 and 3.0 phr, that of the primary accelerator is preferably between
• accelerator primary or secondary
• any compound capable of acting as an accelerator of vulcanization of diene elastomers in the presence of sulfur in particular thiazole accelerators and their derivatives, accelerators of thiuram type, zinc dithiocarbamates.
• accelerators are more preferably selected from the group consisting of 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS”), N-cyclohexyl-2-benzothiazyl sulfenamide (abbreviated “CBS”), N, N-dicyclohexyl-2-benzothiazyl sulfenamide (abbreviated “DCBS”), N-tert-butyl-2-benzothiazylsulfenamide (abbreviated “TBBS”), N-tert-butyl-2-benzothiazylsulfenimide (abbreviated “TBSI”), zinc dibenzyldithiocarbamate (in abbreviated "ZBEC”) and mixtures of these compounds.
• MBTS 2-mercaptobenzothiazyl disulfide
• CBS N-cyclohexyl-2-benzothiazyl sulfenamide
• DCBS N-dicyclohex
• the final composition thus obtained can then be calendered, for example in the form of a sheet, a plate especially for a characterization in the laboratory, or extruded, for example to form a rubber profile used for the manufacture of a tread.
• the invention relates to the tires previously described both in the green state (that is to say, before firing) and in the fired state (that is to say, after crosslinking or vulcanization).
• compositions thus obtained are then calendered either in the form of plates (thickness of 2 to 3 mm) or thin sheets of rubber for the measurement of their physical or mechanical properties, or extruded in the form of a tread.
• compositions C1 and C.5 are two reference compositions for a person skilled in the art, based on SBR and BR, conventionally used to manufacture green tire treads for passenger vehicles.
• compositions C.2, C.3, C.4 of the treads of the tires according to the invention are based on BR and a saturated TPS, respectively SEPS, SEEPS, and SEBS.
• compositions C.6, C1, C.8 of the treads of the tires according to the invention are based on BR, SBR and a saturated TPS, respectively SEPS, SEEPS, and SEBS.
• Compositions C1 to C8 all comprise a plasticizer comprising a hydrocarbon resin (a polylimonene resin) and a liquid plasticizer (a MES oil).
• compositions C.2, C.3, C.4 on the one hand and C.6, C1, C.8 on the other hand treads of the tires according to the invention exhibit Shore A hardness values, MA10 and MA100 modules, all of which are increased relative to control compositions C1 and C.5. This increase in stiffness is for the skilled person a recognized indicator of an improvement in the road behavior of vehicles equipped with tires according to the invention. It is then noted that the compositions of the treads of the tire according to the invention have a value of tan ( ⁇ ) 40 ° C. which is substantially equal to that of the control compositions respectively Cl and C.5, which is synonymous with a hysteresis and therefore equivalent rolling resistance.
• silica (Zeosil 1165 MP" from Rhodia, type “HD") - (BET and CTAB: approximately 160 m 7 g);
• DPG Diphenylguanidine
• silica (Zeosil 1165 MP" from Rhodia, type “HD”) - (BET and CTAB: approximately 160 m 2 / g);
• DPG Diphenylguanidine

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• 2009
  • 2009-06-29 FR FR0954405A patent/FR2947275B1/fr not_active Expired - Fee Related
• 2010
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  • 2010-06-28 EP EP10729836.6A patent/EP2449023B1/fr not_active Not-in-force
  • 2010-06-28 US US13/377,856 patent/US8759438B2/en active Active

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