Classifications

• • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F297/00—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer
  • C08F297/06—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the coordination type
  • C08F297/08—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the coordination type polymerising mono-olefins
  • C08F297/083—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the coordination type polymerising mono-olefins the monomers being ethylene or propylene
  • C08F297/086—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the coordination type polymerising mono-olefins the monomers being ethylene or propylene the block polymer contains at least three blocks
• • 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
  • B60C1/0025—Compositions of the sidewalls
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/04—Carbon
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/34—Silicon-containing compounds
  • C08K3/36—Silica
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/014—Additives containing two or more different additives of the same subgroup in C08K

Definitions

• the present invention relates to tires and more particularly to external tire flanks, that is to say, by definition, to the elastomeric layers located radially outside the tire, which are in contact with the ambient air.
• An outer flank is an elastomeric layer disposed outside the carcass reinforcement with respect to the inner cavity of the tire, between the crown and the bead so as to completely or partially cover the region of the carcass reinforcement. extending from the top to the bead.
• This zone includes layers or plies which are here called internal layers of the tire. These are, for example, carcass plies, underlays of bearing belts, tire belt plies or any other layer which does not come into contact with the ambient air or the inflation gas of the tire.
• the outer flank generally consists of a rubber composition comprising predominantly diene elastomers, for example a blend of natural rubber and polybutadiene.
• this composition also comprises at least one anti-ozonant agent intended to reduce the formation and propagation of cracks under prolonged static and dynamic solubilities in the presence of ozone, as well as waxes intended to form a protective coating on the surface of the sidewalls so as to provide additional protection under static stresses.
• the subject of the invention is therefore a tire provided with an external flank, said external flank comprising at least one composition comprising an elastomeric matrix which comprises mainly by weight one or more thermoplastic elastomers comprising at least one elastomeric block and at least one blast. c thermoplastic, or the elastomeric blocks being saturated.
• the tire according to the invention comprising the external flank makes it possible to minimize the appearance of cracks on said flank during exposure to an ozonated atmosphere.
• 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., bounds a and b excluded) while any range of values designated by the term “from a to b” means the range of values from a to b (this is ie including strict bounds a and b).
• part per cent elastomer or "phr” means the part by weight of one component per 100 parts by weight of the elastomer (s), that is to say, the total weight of the or elastomers, whether thermoplastic or non-thermoplastic, of the elastomeric matrix.
• a 60 phr component will mean, for example, 60 g of this component per 100 g of elastomer.
• elastomeric matrix in the present application is meant all the elastomers of the composition.
• thermoplastic elastomers comprising at least one elastomer block and at least one thermoplastic block, the elastomeric block (s) being saturated
• the elastomeric matrix comprises at least 50% by weight, preferably at least less than 65% by weight, more preferably at least 70% by weight, in particular at least 75% by weight, more preferably still greater than 75% by weight of said thermoplastic elastomers with respect to all the elastomers present in the matrix elastomeric composition.
• thermoplastic elastomer By thermoplastic elastomer (TPE) is meant, in a known manner, a polymer of intermediate structure between a thermoplastic polymer and an elastomer.
• thermoplastic elastomer consists of one or more rigid "thermoplastic” segments connected to one or more "elastomeric” flexible segments.
• thermoplastic elastomer or elastomers of the composition of the external flank that can be used according to the invention comprise at least one elastomeric block and at least one thermoplastic block.
• each of these segments or blocks contains at least more than 5, usually more than 10 base units.
• a composition in which a thermoplastic resin or polymer and an elastomer are mixed does not constitute a thermoplastic elastomer in the sense of the present invention.
• thermoplastic elastomers when reference is made to the glass transition temperature of a thermoplastic elastomer, it is the glass transition temperature relative to the elastomeric block (unless otherwise indicated).
• the thermoplastic elastomers have two glass transition temperature peaks (Tg, measured according to ASTM D341 8), the lowest temperature being relative to the elastomer portion of the thermoplastic elastomer, and the temperature the most high being relative to the thermoplastic part of the thermoplastic elastomer.
• Tg glass transition temperature peaks
• the soft spots of the thermoplastic elastomers are generally defined by a Tg less than or equal to the ambient temperature (25 ° C), while the rigid blocks have a Tg greater than or equal to 80 ° C.
• thermoplastic elastomer In order to be both elastomeric and thermoplastic in nature, the thermoplastic elastomer must be provided with sufficiently incompatible blobs (that is to say different because of their respective mass, polarity or Tg) to maintain their properties. properties of blo c elastomer or thermoplastic.
• thermoplastic elastomer (s) usable according to the invention preferably have a glass transition temperature which is less than or equal to 25 ° C., more preferably less than or equal to 10 ° C. and more preferably still less than or equal to -10 ° C.
• the average molecular weight in number (denoted Mn) of the thermoplastic elastomers is preferably between 30,000 and 500,000 g / mol, more preferably between 40,000 and 400,000 g / mol, more preferably between 50,000 and 300 000 g / mo l.
• Mn average molecular weight in number
• the number-average molecular weight (Mn) of the thermoplastic elastomers is determined in known manner by steric exclusion chromatography (SEC).
• SEC steric exclusion chromatography
• the sample is solubilized beforehand in a suitable solvent at a concentration of approximately 2 g / l; then the solution is filtered on 0.45 ⁇ porosity filter before injection.
• the apparatus used is a "WATERS alliance" chromatographic chain.
• the injected volume of the solution of the polymer sample is 100 ⁇ .
• the detector is a differential refractometer "WATERS 2410" and its associated chromatographic data exploitation software is the "EMPOWER" system. The conditions are adaptable by those skilled in the art.
• the elution solvent is hexafluoroisopranol with sodium trifluoroactetate salt at a concentration of 0.02 M, the flow rate of 0.5 ml / min, the temperature of the system 35 ° C and the analysis time 90 min.
• a set of three PHENOMENEX columns in series, of trade names "PHENOGEL" (pore sizes: 10 5 , 10 4 , 10 3 A) is used.
• PHENOGEL pore sizes: 10 5 , 10 4 , 10 3 A
• the sample is solubilized beforehand in tetrahydrofuran at a concentration of approximately 1 g / L; then the solution is filtered on 0.45 ⁇ porosity filter before injection.
• the apparatus used is a "WATERS alliance" chromatographic chain.
• the elution solvent is tetrahydrofuran
• the flow rate is 0.7 mL / min
• the temperature of the system is 35 ° C.
• the analysis time is 90 minutes.
• 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 chromatographic data exploitation software is the system "WATERS MILLENNIUM".
• the mean calculated average masses relate to a calibration curve made with polystyrene standards.
• thermoplastic elastomers that can be used according to the invention can be copolymers with a small number of blocks (less than 5, typically 2 or 3), in which case these blocks preferably have high masses, greater than 15,000 g / mol.
• thermoplastic elastomers may also be copolymers with a large number of blocks (more than 30, typically from 50 to 500) smaller, in which case these blocks preferably have low masses, for example from 500 to 5000 g / mol, these thermoplastic elastomers will be called multiblock thermoplastic elastomers thereafter.
• thermoplastic elastomers that can be used according to the invention are in a linear form.
• thermoplastic elastomers are diblock copolymers: thermoplastic blo c / elastomeric block.
• thermoplastic elastomers are triblock copolymers: thermoplastic block / elastomer block / thermoplastic block, that is to say a central elastomeric block and a terminal thermoplastic block at each of the two ends. elastomeric blo c.
• thermoplastic elastomers consist of a linear sequence of elastomeric blocks and thermoplastic blocks (multiblock thermoplastic elastomers).
• thermoplastic elastomers that can be used according to the invention are in a star shape with at least three branches.
• thermoplastic elastomers may then consist of a star-shaped elastomer blo c at at least three branches and a thermoplastic blo c, located at the end of each of the branches of the elastomeric block.
• the number of branches of the central elastomer can vary, for example from 3 to 12, and preferably from 3 to 6.
• thermoplastic elastomers that can be used according to the invention are in a branched or dendrimer form.
• the thermoplastic elastomers can then consist of a connected elastomeric block or dendrimer and a thermoplastic block, located at the end of the branches of the elastomer dendrimer block.
• thermoplastic elastomer (s) that can be used according to the invention comprise at least one elastomer block and at least one thermoplastic block, the elastomeric block (s) being saturated.
• saturated elastomeric block it is meant that this blo c comprises a rate of units or units derived from conjugated diene monomers which is less than 15 mol%.
• Saturated elastomeric blocks are generally constituted by the polymerization of ethylenic monomers. Mention may in particular be made of polyalkylene blocks such as ethylene-propylene or ethylene-butylene random copolymers. These saturated elastomeric blocks can also be obtained by hydrogenation of unsaturated elastomeric blocks. By unsaturated elastomer block, it is meant that this blo c mainly comprises units comprising ethylenic unsaturations.
• the saturated elastomeric blocks can in particular be constituted by polyethers, in particular polytetramethylene glyco (PTMG) and polyethylene glycols (PEG).
• PTMG polytetramethylene glyco
• PEG polyethylene glycols
• monomers polymerized to form a saturated elastomeric block can be randomly copolymerized with at least one other monomer to form a saturated elastomeric block.
• the molar fraction of polymerized monomer other than an ethylenic monomer, relative to the total number of units of the saturated elastomeric block must be such that this block retains its saturated elastomer properties.
• the molar fraction of this other comonomer may range from 0 to 50%, more preferably from 0 to 45% and even more preferably from 0 to 40%.
• conjugated C4-C14 dienes may be copolymerized with the ethylenic monomers, the ethylenic units remaining the majority as seen above.
• these conjugated dienes are chosen from isoprene, butadiene, 1-methylbutadiene, 2-methylbutadiene, 2,3-dimethyl-1,3-butadiene, 2,4-dimethyl-1,3- butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 2,3-dimethyl-1 , 3-pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene, 3-methyl-1,3-hexadiene, 4-methyl-1,3-hexadiene, 5-methyl-3-methyl-1,3-hexadiene, 1,3-hexadiene, 2,3-dimethyl-1,3-hexadiene, 2,4-dimethyl-1,3-hexadiene, 2,5-dimethyl-1,3-hexadiene, 2-neopentylbutad
• the elastomeric blocks of the thermoplastic elastomers have a number-average molecular weight ("Mn") ranging from 25000 g / mol to 350000 g / mol, preferably from 35000 g / mol to 250000 g / mol of in order to give the thermoplastic elastomers good elastomeric properties and sufficient mechanical strength and compatible with the use on the external side of the tire.
• Mn number-average molecular weight
• the elastomeric block or blocks may also be blocks comprising several types of ethylenic monomers as defined above.
• the elastomeric block or blocks are chosen from the group consisting of ethylenic elastomers, polyethers and mixtures of these polymers.
• the elastomeric block or blocks are selected from the group consisting of polyethers, copolymers of ethylene and propylene, copolymers of ethylene and butylene, and mixtures of these polymers.
• thermoplastic polymers that can be used according to the invention also comprise at least one thermoplastic block.
• thermoplastic block is meant a block consisting of polymerized monomers and having a glass transition temperature, or a melting temperature in the case of semicrystalline polymers, greater than or equal to 80 ° C, preferably ranging from 80 ° C to 250 ° C, more preferably ranging from 80 ° C to 200 ° C, and in particular ranging from 80 ° C to 1 80 ° C.
• thermoplastic block or blocks can be made from polymerized monomers of various kinds.
• thermoplastic block or blocks may consist of the following blocks or a mixture of the following blocks:
• polyolefins polyethylene, polypropylene
• polyesters polyacetals
• polyethers polyethylene oxide, polyphenylene ether
• FEP polyfluoro
• thermoplastic copolymers such as acrylonitrile-butadiene-styrene copolymer (ABS).
• thermoplastic block or blocks can also be obtained from monomers chosen from:
• indene and its derivatives such as, for example, 2-methylindene, 3-methylindene, 4-methylindene, dimethylindene, 2-phenylindene, 3-phenylindene and 4-phenylindene; those skilled in the art may for example refer to the patent document US4946899, by the inventors Kennedy, Puskas, Kaszas and Hager and J. E documents. Puskas, G. Kaszas, J.P. Kennedy, W. G. Hager Journal of Polymer Science Part A: Polymer Chemistry (1992) 30, 41 and J.P. Kennedy, N. Meguriya, B. Keszler, Macromolecules (1991) 24 (25), 6572-6577;
• the above monomers can be copolymerized with at least one other monomer as long as it does not modify the thermoplastic character of the block, that is to say say that the block has a glass transition temperature, or a melting temperature in the case of semi-crystalline polymers, greater than or equal to 80 ° C.
• this other monomer capable of copolymerizing with the polymerized monomer may be chosen from diene monomers, more particularly conjugated diene monomers having 4 to 14 carbon atoms, and vinylaromatic type monomers having 8 to 18 carbon atoms. at 20 carbon atoms.
• vinylaromatic compounds are especially suitable styrenic monomers, namely methylstyrenes, para-tert-butylstyrene, chlorostyrenes, bromostyrenes, fluorostyrenes or para-hydroxy-styrene.
• the vinylaromatic comonomer is styrene.
• thermoplastic block (s) may be chosen from polystyrenes and polymers comprising at least one polystyrene block.
• Polystyrenes are obtained from styrenic monomers.
• styrene monomer any monomer comprising styrene, unsubstituted as substituted; among the substituted styrenes may be mentioned, for example, methylstyrenes (for example ⁇ -methylstyrene, m-methylstyrene or p-methylstyrene, alpha-methylstyrene, alpha-2-dimethylstyrene, alpha-4-dimethylstyrene or diphenylethylene), para-tert-butylstyrene, chlorostyrenes (for example, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene or 2,4-dichlorostyrene).
• methylstyrenes for example ⁇ -methylstyrene, m-methylstyrene or p-methylstyren
• thermoplastic block (s) of the thermoplastic elastomers that can be used according to the invention may also consist of several of the thermoplastic blocks as defined above.
• the proportion of the thermoplastic blocks in the thermoplastic elastomers that can be used according to the invention is determined firstly by the thermoplastic properties that the thermoplastic elastomers must exhibit.
• thermoplastic block or blocks are preferably present in proportions sufficient to preserve the thermoplastic nature of the thermoplastic elastomers that can be used according to the invention.
• the minimum level of thermoplastic blocks in thermoplastic elastomers may vary depending on the conditions of use of the thermoplastic elastomers.
• thermoplastic elastomers to deform during the preparation of the tire can also contribute to determining the proportion of thermoplastic blocks in the thermoplastic elastomers used according to the invention.
• the thermoplastic blocks of the thermoplastic elastomers have a number average molecular weight ("Mn") ranging from 5,000 g / m 2 to 150,000 g / m 2, so as to give the thermoplastic elastomers good elastomeric properties and sufficient mechanical strength and compatible with the use on the external side of the tire.
• Mn number average molecular weight
• thermoplastic block (s) are chosen from the group consisting of polystyrenes, polyesters, polyamides, polyurethanes, and mixtures of these polymers.
• thermoplastic block (s) are selected from the group consisting of polystyrenes, polyesters, polyamides, and blends of these polymers.
• thermoplastic elastomer usable according to the invention there may be mentioned a copolymer whose elastomeric portion is saturated, and comprising styrenes blo cs and alkylene blocks.
• Alkylene blocks are preferably ethylene, propylene or butylene.
• thermoplastic elastomers that can be used according to the invention are chosen from the following diblock, linear or starred triblock copolymers: styrene / ethylene / butylene (SEB), styrene / ethylene / propylene (SEP), styrene / ethylene / ethylene / propylene ( SEEP), styrene / ethylene / butylene / styrene (SEBS), styrene / ethylene / propylene / styrene (SEP S), styrene / ethylene / ethylene / propylene / styrene (SEEPS), styrene / isobutylene (SIB), styrene / isobutylene / styrene (SIBS), and mixtures of these copolymers.
• SEB styrene / ethylene / butylene
• the weight content of styrene in each thermoplastic block of the thermoplastic elastomer (s) usable according to the invention is less than or equal to 15%.
• the tire has a low hysteresis.
• the tire has improved rolling resistance.
• the level of thermoplastic elastomer (s) of the composition varies from 65 to 100 phr, preferably ranges from 70 to 100 phr, more preferably varies from 75 to 100 phr, and even more preferably varies from 95 to 100 pce.
• thermoplastic elastomers that can be used according to the invention are multiblock thermoplastic elastomers, for example triblo cs.
• copolymers comprising random copolymer blocks of ethylene and propylene / polypropylene, polyether / polyester PET (polyethylene terephthalate) or polyether / polyester PBT (polybutylene terephthalate) ( COPE), Polyether / Polyamide (PEBA).
• the polyether blocks are preferably polyethylene glycols.
• thermoplastic elastomers that can be used according to the invention are chosen from the following copolymers: styrene / ethylene / butylene / styrene (SEBS), polyether / polyester (COPE), polyether / polyamide (PEBA), and the mixtures of these copolymers.
• SEBS styrene / ethylene / butylene / styrene
• COPE polyether / polyester
• PEBA polyether / polyamide
• thermoplastic elastomers that are commercially available and usable according to the invention, mention may be made of the elastomers of SEPS, SEEPS or SEBS type sold by Kraton under the name "Kraton G” (for example products 61650, 6165 1, 61654, 61730) or the Kuraray company under the name "Septon” (for example “Septon 2007”, “Septon 4033", “Septon 004"); or the SI S type elastomers marketed by Kuraray, under the name "Hybrar 5 125", or marketed by Kraton under the name "D 1 161" or else the linear SBS elastomers marketed by Polimeri Europa under the name “Europrene” SOL T 1 66 "or star SBS marketed by Kraton under the name” D 1 1 84 ". Mention may also be made of the elastomers marketed by Dexco Polymers under the name “Vector” (for example “Vector 41 14", "V
• thermoplastic elastomers exemplified above are mixed together in the composition of the external sidewall of the tire that can be used according to the invention.
• thermoplastic elastomers presented above are mixed with other thermoplastic elastomers, the elastomeric block or blocks being unsaturated.
• thermoplastic elastomers presented above are in admixture with other non-thermoplastic elastomers.
• thermoplastic elastomer or elastomers that can be used according to the invention are the only elastomers of the elastomeric matrix of the composition.
• thermoplastic elastomer (s) described above are sufficient on their own for the external sidewall of the tire according to the invention to be usable.
• the composition according to the invention may then comprise one or more diene rubbers as non-thermoplastic elastomer.
• elastomer or “diene” rubber should be understood in known manner one or more elastomers derived at least in part (that is to say a homopolymer or a copolymer) of monomers dienes (monomers carrying two double bonds carbon-carbon , conjugated or not).
• diene elastomers can be classified into two categories: "essentially unsaturated” or "essentially saturated”.
• essentially unsaturated is generally understood to mean a diene elastomer derived at least in part from conjugated diene monomers having a molar content of units or units of diene origin (conjugated dienes) which is greater than 15%.
• highly unsaturated diene elastomer is particularly understood to mean a diene elastomer having a molar content of units of diene origin (conjugated dienes) which is greater than 50%.
• diene elastomers such as certain butyl rubbers or copolymers of dienes and alpha-olefins of the EPDM type can be described as "essentially saturated" diene elastomers (level of units of diene origin which are weak or very weak, always less than 15%).
• diene elastomer is more particularly understood, whatever the category above, which can be used in the composition that can be used according to the invention:
• 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.
• 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 vinyl aromatic compounds are, for example, styrene, ortho-, meta-, para-methylstyrene, the "vinyl-toluene" commercial mixture, para-tertiarybutylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene.
• the copolymers of the diene elastomers may contain between 99% and 20% by weight of diene units and between 1% and 80% by weight of vinylaromatic units.
• the diene elastomers may have any microstructure which is a function of the polymerization conditions used, in particular the presence or absence of a modifying and / or randomizing agent and the amounts of modifying and / or randomizing agent used.
• the elastomers may for example be prepared in dispersion or in solution; they may be coupled and / or starred or functionalized with a coupling agent and / or starring or functionalization.
• silano or polysiloxane functional groups having a silanol end (as described for example in FR 2 740 778 or US Pat. No. 6,013,771), groups alkoxysilane (as described for example in FR 2,765,882 or US 5,977,238), carboxylic groups (as described for example in WO 01/92402 or US 6 8 15 473, WO 2004/096865 or US 2006/0089445).
• elastomers such as SBR, BR, NR or IR of the epoxidized type.
• composition used in the external sidewall of the tire according to the invention may also comprise one or more reinforcing filler (s).
• any type of filler usually used for the manufacture of tires for example an organic filler such as carbon black, an inorganic filler such as silica, or a blend of these two types of filler, can be used. especially a blend of carbon black and silica.
• the reinforcing filler (s) is (are) carbon black and / or silica, preferably carbon black.
• carbon blacks are suitable all the carbon blacks conventionally used in tires (so-called pneumatic grade blacks).
• the reinforcing carbon blacks of the series 1 00, 200 or 300 for example blacks NI 15, N 134, N 234, N 326, N 31 O, N 339, N 347, N 375, or even more particularly , according to the targeted applications, the blacks of higher series (eg N660, N683, N772), or even N990.
• any inorganic or mineral filler (regardless of its color and origin (natural or synthetic), also called “white” filler, “clear” filler or “non-black filler” as opposed to carbon black, capable of reinforcing on its own, with no other means than an intermediate coupling agent, a composition intended for the manufacture of tires, in particular
• Other terms capable of replacing, in its reinforcing function, a conventional carbon black of pneumatic grade, such a charge 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.
• 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 of silica (SiO 2), or of the aluminous type, in particular alumina (Al 2 O 3).
• the silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or fumed silica having a BET surface and a CTAB specific surface both less than 450 m 2 / g, preferably from 30 to 400 m 2 / g.
• HDS highly dispersible precipitated silicas
• At least one bifunctional coupling agent intended to ensure a sufficient chemical and / or physical connection between the inorganic filler (surface of its particles) and the elastomer, in particular organosilanes or bifunctional polyorganosiloxanes.
• the optional voiding rate of the reinforcing filler in the composition is in a range from 0 to 30%, which corresponds approximately to a level of 0 to 1 00 phr for a composition without plasticizer.
• the composition according to the invention comprises less than 30 phr of reinforcing filler, and more preferably less than 10 phr.
• the composition does not contain a reinforcing filler.
• composition used in the external sidewall of the tire according to the invention may contain one or more inert micrometric fillers such as lamellar fillers known to those skilled in the art.
• the composition used in the external sidewall of the tire according to the invention does not contain a micrometric load.
• thermoplastic elastomer (s) described above are sufficient on their own for the external sidewall of the tire according to the invention to be usable.
• the composition does not contain a crosslinking system.
• the composition used in the outer sidewall of the tire according to the invention may also comprise at least one plasticizing agent, such as an oil (or plasticizing oil or oil extension) or a plasticizing resin whose function is to facilitate the implementation of the outer flank, particularly its integration in the obj and pneumatic by a lowering of the module and an increase in the tackifying power.
• at least one plasticizing agent such as an oil (or plasticizing oil or oil extension) or a plasticizing resin whose function is to facilitate the implementation of the outer flank, particularly its integration in the obj and pneumatic by a lowering of the module and an increase in the tackifying power.
• plasticizer which may be a resin or an extension oil may be used.
• resin is hereby reserved, by definition known to those skilled in the art, to a compound which is soluble at room temperature (23 ° C), as opposed to a liquid plasticizer such as an oil extension or plasticizing oil.
• these oils which are more or less viscous, are liquids (ie, as a reminder, substances having the capacity to eventually take on the shape of their containers), as opposed to in particular to resins or rubbers which are inherently solid.
• Hydrocarbon resins are polymers well known to those skilled in the art, essentially based on carbon and hydrogen, which can be used in particular as plasticizers in elastomeric compositions. They have been described for example in the book entitled "Hydrocarbon Resins" by R. Mildenberg, M. Zander and G. Co llin (New York, VCH, 1997, ISBN 3 -527-28617-9) whose chapter 5 is devoted to their applications, in particular in pneumatic rubber (5.5 Rubber Tires and Mechanical Goods). They may be aliphatic, cycloaliphatic, aromatic, hydrogenated aromatic, aliphatic / aromatic type, that is to say based on aliphatic and / or aromatic monomers.
• Tg is preferably greater than 0 ° C., especially greater than 20 ° C. (most often between 30 ° C. and 120 ° C.).
• these hydrocarbon resins can also be described as thermoplastic resins in that they are They are heated by heating and can thus be molded. They can also be defined by a point or softening point ("so ftening point"), the temperature at which the product, for example in the form of a powder, coalesces.
• the cooling temperature of a hydrocarbon resin is generally about 50 to 60 ° C higher than its Tg value.
• hydrocarbon resins By way of examples of such hydrocarbon resins, mention may be made of those selected from the group consisting of homopolymer or copolymer resins of cyclopentadiene (abbreviated as CPD) or dicyclopentadiene (abbreviated to DCPD), terpene homopolymer or copolymer resins. terpene homopolymer or terpene copolymer resins, C5 homopolymer or copolymer resins, C9 homopolymer or copolymer resins, alpha-methyl-styrene homopolymer or copolymer resins, and mixtures of these resins.
• CPD cyclopentadiene
• DCPD dicyclopentadiene
• copolymer resins examples include those selected from the group consisting of (D) CPD / vinylaromatic copolymer resins, (D) CPD / terpene copolymer resins, (D) copolymer resins CPD / C5 cut, (D) CPD / C5 cut copolymer resins, (D) CPD / C9 cut copolymer resins, terpene / vinylaromatic copolymer resins, terpene / phenol copolymer resins, copolymer resins C5 / vinylaromatic, 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. .
• Suitable vinylaromatic monomers are, for example, styrene, alpha-methylstyrene, ortho-methylstyrene, metamethylstyrene, para-methylstyrene, vinyl-toluene, para-tertiarybutylstyrene, methoxystyrenes, chlorostyrenes, hydroxystyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, any vinylaromatic monomer resulting from a C9 cut (or more generally from a C8 to C10 cut).
• the resins selected from the group consisting of homopolymer resins (D) CPD, copolymer resins (D) CPD / styrene, polylimonene resins, limonene / styrene copolymer resins, resins of limonene / D copolymer (CPD), C5 / styrene cut copolymer resins, C5 / C9 cut copolymer resins, and mixtures of these resins.
• D homopolymer resins
• D copolymer resins
• D copolymer resins
• polylimonene resins limonene / styrene copolymer resins
• resins of limonene / D copolymer (CPD) resins of limonene / D copolymer
• C5 / styrene cut copolymer resins C5 / C9 cut copolymer resins
• the extender oil is selected from the group consisting of polyolefinic oils (that is, derived from the polymerization of o-olefins, monoolefins or diolefins), paraffinic oils, naphthenic oils. (low or high viscosity), aromatic oils, mineral oils, and mixtures of these oils.
• polyolefinic oils that is, derived from the polymerization of o-olefins, monoolefins or diolefins
• paraffinic oils naphthenic oils. (low or high viscosity)
• aromatic oils aromatic oils
• mineral oils and mixtures of these oils.
• the average molecular weight in number (Mn) of the extender oil is preferably between 200 and 25,000 g / mol, more preferably between 300 and 10,000 g / mol.
• Mn average molecular weight in number
• the number average molecular weight (Mn) of the extender oil is determined by steric exclusion chromatography (SEC), the sample being previously solubilized in tetrahydrofuran at a concentration of about 1 g / l; then the solution is filtered on 0.45 ⁇ porosity filter before injection.
• the apparatus is the "WATERS alliance" chromatographic chain.
• the eluting solvent is tetrahydrofuran
• the flow rate is 1 ml / min
• the temperature of the system is 35 ° C
• the analysis time is 30 min.
• a set of two “WATERS” bottles called “STYRAGEL HT6E” is used.
• the volume injected from the solution of the polymer sample is 100 ⁇ .
• 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.
• the level of plasticizer varies from 2 to 60 phr, more preferably from 3 to 50 phr. Below the minimum indicated, the presence of plasticizer is not sensitive. Beyond the maximum recommended, there is a risk of insufficient cohesion of the composition.
• composition that can be used in the external sidewall of the tire according to the invention may also comprise a lamellar filler.
• lamellar filler advantageously makes it possible to lower the coefficient of permeability (thus increasing the seal) of the composition, without excessively increasing its modulus, which makes it possible to maintain the ease of integration of the external flank. in the obj and pneumatic.
• lamellar fillers in English “platy fillers" are well known to those skilled in the art. They have been used in particular in pneumatic tires to reduce the permeability of conventional waterproof layers based on butyl rubber. They are generally used at relatively low rates, usually not exceeding 1 to 50 phr, ie variable volumetric rates, in particular from 0.1 to 25% by volume of elastomeric composition, and preferably from 1 to 20% by volume.
• L L / E
• L the length (or larger dimension)
• E the average thickness of these lamellar fillers, these averages being calculated in number.
• Form ratios of tens or even hundreds are common.
• Their average length is preferably greater than 1 ⁇ (that is to say that it is then micrometric said lamellar charges), typically between a few ⁇ (for example 5 ⁇ ) and a few hundreds of ⁇ (by example the 500 or 800 ⁇ ).
• the lamellar fillers used in accordance with the invention are chosen from the group consisting of graphites, silicon-based lamellar mineral fillers and mixtures of such fillers.
• graphite is generally meant a set of non - compact hexagonal sheets of carbon atoms: graphenes.
• Graphite a hexagonal crystalline system, has an ABAB type stack where plane B is translated relative to plane A.
• Graphite can not be considered as a reinforcing filler, however it can be considered as a semi-reinforcing (or partially reinforcing) filler insofar as it allows an increase in the tensile modulus of an elastomeric composition in which it is incorporated .
• graphite can more particularly be understood as meaning that can be used in the compositions that can be used according to the invention:
• any expanded natural graphite being made in two stages: intercalation of one or more chemical compounds in the liquid state, for example an acid, between the graphene planes of a natural graphite by chemical treatment and high temperature expansion;
• composition that can be used in the external sidewall of the tire according to the invention may contain a single graphite or a mixture of several graphites, so it is possible to have a blend of natural graphite and / or expanded graphite and / or synthetic graphite.
• Graphite as defined above can be morphologically in a lamellar form or not, and in both cases be assimilated to a lamellar filler in the sense of the present invention.
• the graphite is present in the elastomeric composition at levels ranging from 1 phr to 60 phr, and preferably between 5 and 30 phr.
• lamellar inorganic fillers based on silicon are suitable phyllosilicates and particularly those included in the group consisting of smectites, kaolin, talc, mica and vermiculite.
• the organic structure with which the inert filler is associated is a surfactant of formula: -M + R 3 R 4 R 5 -; where M represents a nitrogen, sulfur, phosphorus or pyridine atom, and wherein R 3 , R 4 , and R 5 represents a hydrogen atom, an alkyl group, an aryl group or an allyl group, R 3 , R 4 and R 5 being identical or different.
• organomodified montmorillonites are suitable for the invention.
• montmorillonites modified with a surfactant such as a dioctadecyldimethyl dihydrogenated quaternary ammonium salt.
• a surfactant such as a dioctadecyldimethyl dihydrogenated quaternary ammonium salt.
• Such organomodified montmorillonite is marketed in particular by Southern Clay Products under the trade name: "CLOISITE 6A and 20A".
• surfactants based on quaternary ammonium salts may be further used to modify the phyllosilicates as described in the patent application WO06 / 047509.
• micas examples include micas marketed by the company CMMP (Mica-MU®, Mica-Soft®, Briomica® for example), those sold by YAMAGUCHI (A5 1 S, A41 S, SYA-21 R , SYA-21 RS, A21 S, SYA-4 1 R), vermiculites (in particular Shawatec® vermiculite marketed by CMMP or vermiculite Micro lite® marketed by WR Grace), modified or treated micas (for example, the range). Iriodin® marketed by Merck).
• graphites mention may be made of graphites marketed by Timcal (Timrex® range).
• talcs mention may be made of talcs marketed by Luzenac.
• inert fillers mentioned above are indeed particularly interesting because they make it possible to improve the impermeability of the compositions in which they are dispersed with an adequate level.
• their level may vary from 1 phr to 80 phr, and preferably from 3 to 40 phr.
• lamellar fillers into the composition can be carried out according to various known methods, for example by mixing in solution, by mass mixing in an internal mixer, or by extrusion mixing.
• composition that can be used for the external sidewall of the tire according to the invention may further comprise the various additives usually present in the external sides known to those skilled in the art.
• Non-reinforcing or inert fillers other than the previously described lamellar fillers, plasticizers other than the above-mentioned extender oils, UV stabilizers, various processing agents or other stabilizers, or suitable promoters may be mentioned, for example. to promote the adhesion to the rest of the structure of the obj and pneumatic.
• composition B A composition usable in the tire according to the invention (composition B) and a composition usable in a comparative tire (composition A) were prepared from the ingredients and contents in Table I below. The contents are expressed in phr.
• Copolymer blo c comprising 13% by weight of styrene, Tuftec H 1221 series from Asahi Kase ⁇ ,
• Composition A was prepared in appropriate mixers, using two successive preparation phases according to a general procedure well known to those skilled in the art: a first thermomechanical working phase or mixing (sometimes referred to as a "non-productive” phase) at high temperature, up to a maximum temperature of 1 60 ° C, followed by a second phase of mechanical work (sometimes referred to as a "productive” phase) at a lower temperature of 60 ° C, a finishing phase during which is incorporated the crosslinking system.
• a first thermomechanical working phase or mixing sometimes referred to as a "non-productive” phase
• a second phase of mechanical work sometimes referred to as a "productive” phase
• the implementation of the elastomeric composition is carried out by means of an external mixer.
• composition B is prepared by extrusion molding or injection from a raw material available in the form of beads or granules, here by means of a twin-screw extruder at a minimum temperature of 160 ° C. An outer flank comprising composition B was obtained. Said outer side is then mounted on a tire.
• the tire provided with the external sidewall comprising composition A is called pneumatic tire A.
• the tire provided with the external sidewall comprising composition B is called tire B.
• Both tires A and B are mounted and inflated, then loaded and placed in a cell under an atmosphere of ozone for 15 days.
• the ozone concentration in the cell is maintained at 40 ppm and the temperature is 40 ° C.
• the tires are arrowed at 20% of deformation for the flank portion.
• the rolling resistance of tires is measured over a distance, according to ISO 87-67 (1992).
• the tire B according to the invention has improved ozone resistance with respect to the reference tire.
• the tire B according to the invention has improved rolling resistance relative to the reference tire.

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• 2016
  • 2016-12-02 FR FR1661878A patent/FR3059596A1/fr not_active Withdrawn
• 2017
  • 2017-11-30 EP EP17804588.6A patent/EP3548305A1/de not_active Withdrawn
  • 2017-11-30 CN CN201780074829.8A patent/CN110023098B/zh active Active
  • 2017-11-30 US US16/465,692 patent/US11352459B2/en active Active
  • 2017-11-30 WO PCT/EP2017/081015 patent/WO2018100080A1/fr unknown

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