Classifications

• • 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
  • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F210/02—Ethene

Definitions

• Rubber composition comprising a highly saturated diene elastomer
• the field of the present invention is that of rubber compositions based on highly saturated diene elastomer intended to be used in a tire, in particular in its tread.
• the Applicant has found a rubber composition which makes it possible to meet this need in the field of application of highly saturated diene elastomers to rubber compositions for the tire, and in particular for the tread.
• a rubber composition which combines the use of a highly saturated diene elastomer with the use of a liquid functionalized butadiene polymer which makes it possible to increase the rigidity while reducing significantly the hysteresis of the composition while a composition using a non-functional liquid polybutadiene degrades these two properties.
• These improved properties promise to give the tire good weather resistance properties. rolling and improved road behavior, particularly when transporting heavy loads.
• a first object of the invention is a rubber composition based on at least
• liquid butadiene polymer functionalized at the end of the chain with an alkoxysilyl function, optionally partially or completely hydrolyzed.
• Another object of the invention is a pneumatic or non-pneumatic tire which comprises a rubber composition according to the invention, preferably in its tread.
• Rubber composition based on at least
• liquid butadiene polymer functionalized at the chain end with an alkoxysilyl function, optionally partially or completely hydrolyzed, having a number average molar mass (Mn) greater than or equal to 1,000 g/mol.
• Rubber composition according to any one of the preceding embodiments in which the ethylene units represent at least 60% by mole of the monomer units of the highly saturated diene copolymer, preferably from 65% to 90% by mole of the monomer units of the copolymer highly saturated diene.
• 1,3-diene is 1,3-butadiene, isoprene, myrcene or P-famesene, or a mixture of myrcene and P -famesene, preferably 1,3-butadiene.
• liquid butadiene polymer is a liquid polybutadiene functionalized at the end of the chain with an alkoxysilyl function, optionally partially or completely hydrolyzed.
• composition according to any one of the preceding embodiments in which the alkoxysilyl functions are functions corresponding to the formula Si(OR)s, in which each R, independently of the others, denotes a hydrogen atom or a C1-alkyl C10, preferably C1-C4, preferably C1-C4 alkyl.
• composition according to any one of the preceding embodiments in which the alkoxysilyl functions are trimethoxysilyl or triethoxysilyl functions, optionally partially or completely hydrolyzed.
• composition according to any one of the preceding embodiments in which the level of liquid butadiene polymer functionalized at the end of the chain with an alkoxysilyl function, optionally partially or completely hydrolyzed, is included in a range ranging from 0.5 to 25 phr, preferably 5 to 15 pce.
• liquid butadiene polymer has a number average molar mass greater than or equal to 1000 g/mol and less than or equal to 50000 g/mol, preferably less than or equal to 10000 g/mol, even more preferably less than or equal to 5000 g/mol.
• Pneumatic or non-pneumatic tire comprising a composition according to any of the preceding embodiments.
• Pneumatic or non-pneumatic tire according to the previous embodiment comprising a composition according to any one of embodiments 1 to 20 in all or part of its tread.
• composition based on is meant a composition comprising the mixture and/or the in situ reaction product of the different constituents used, some of these constituents being able to react and/or being intended to react with each other, at least less partially, during the different phases of manufacturing the composition; the composition can thus be in the totally or partially crosslinked state or in the non-crosslinked state.
• part by weight per hundred parts by weight of elastomer (or pce) is meant for the purposes of the present invention, the part, by mass per hundred parts by mass of elastomer.
• any interval of values designated by the expression "between a and b" represents the range of values going from more than a to less than b (that is to say limits a and b excluded) while any interval of values designated by the expression “from a to b” means the range of values going from a to b (that is to say including the strict limits a and b).
• any interval of values designated by the expression “from a to b” means the range of values going from a to b (that is to say including the strict limits a and b).
• the term “all of the monomer units of the elastomer” or “all of the monomer units of the elastomer” is understood to mean all the repetition units constituting the elastomer which result from the insertion of the monomers. in the elastomer chain by polymerization. Unless otherwise indicated, the contents of a monomer unit or repeating unit in the highly saturated diene elastomer are given in molar percentage calculated on the basis of all the monomer units of the elastomer.
• a majority compound we mean in the sense of the present invention that this compound is the majority among the compounds of the same type in the composition, that is to say that it is the one which represents the greatest quantity by mass among the compounds of the same type.
• a majority elastomer is the elastomer representing the greatest mass relative to the total mass of the elastomers in the composition.
• a so-called majority charge is that representing the greatest mass among the charges in the composition.
• a “minority” compound is a compound that does not represent the largest mass fraction among compounds of the same type. Preferably by majority, we mean a mass proportion of more than 50%; when the compound represents 100% by weight, it is also qualified as “majority”.
• the compounds mentioned in the description may be of fossil or biosourced origin. In the latter case, they can be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass. In the same way, the compounds mentioned can also come from the recycling of materials already used, that is to say they can be, partially or totally, from a recycling process, or even obtained from materials raw materials themselves resulting from a recycling process. This concerns in particular polymers, fillers, etc.
• elastomeric matrix we mean all of the elastomers in the composition.
• the elastomer matrix mainly comprises at least one highly saturated diene elastomer, namely a copolymer containing ethylene units and 1,3-diene units (hereinafter referred to as "the copolymer").
• the highly saturated diene elastomer useful for the purposes of the invention, is a copolymer, preferably statistical.
• the term “statistical copolymer” means a copolymer in which the sequential distribution of the monomer units obeys a known statistical law.
• the highly saturated diene elastomer useful for the purposes of the invention is a copolymer which comprises ethylene units resulting from the polymerization of ethylene.
• ethylene unit refers to the pattern
• the highly saturated diene elastomer is rich in ethylene units, since the ethylene units represent at least 50% by mole of all the monomer units of the elastomer.
• the maximum proportion of ethylene units is fixed by the elastomeric nature of the polymer, this proportion is preferably at most 95% by mole, more preferably at most 90% by mole, even more preferably at most 85% by mole.
• the highly saturated diene elastomer comprises from 50% to 95 molar% of ethylene units, molar percentage calculated on the basis of all the monomer units of the highly saturated diene elastomer.
• the highly saturated diene elastomer comprises at least 60 mole% of ethylene unit.
• the ethylene units preferably represent at least 65% by mole of all the monomer units of the highly saturated diene elastomer, more preferably at least 70% by mole of all the monomer units of the highly saturated diene elastomer.
• the highly saturated diene elastomer More preferably, the highly saturated diene elastomer comprises from 65% to 90 molar% of ethylene unit, molar percentage calculated on the basis of all the monomer units of the highly saturated diene elastomer.
• the highly saturated diene elastomer according to the invention being a copolymer of ethylene and a 1,3-diene, it also comprises 1,3-diene units resulting from the polymerization of a 1,3-diene.
• 1,3-diene unit refers to the units resulting from the insertion of 1,3-diene.
• the 1,3-diene units are those for example of a 1,3-diene having 4 to 24 carbon atoms.
• 1,3-diene suitable in particular is butadiene, isoprene, 2,3-di(C1 to C5 alkyl)-1,3-butadiene such as for example 2,3-dimethyl-1,3 -butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene or 2-methyl-3-isopropyl-1,3-butadiene, aryl-
• 1,3-butadiene such as phenyl-1,3-butadiene, 1,3-pentadiene.
• the highly saturated diene elastomer is preferably a copolymer of ethylene and a
• 1,3-diene from 1,3-butadiene, isoprene, myrcene, P-famesene and a mixture of myrcene and P-famesene.
• the 1,3-diene is 1,3-butadiene or isoprene, more preferably 1,3-butadiene, in which case the highly saturated diene elastomer is a copolymer of ethylene and 1,3- butadiene, preferably statistical.
• the diene elastomer strongly saturated may additionally contain 1,2-cyclohexanediyl units.
• the presence of these cyclic structures in the copolymer results from a very specific insertion of ethylene and 1,3-butadiene during polymerization.
• the content of 1,2-cyclohexanediyl units in the copolymer varies depending on the respective contents of ethylene and 1,3-butadiene in the copolymer.
• the copolymer preferably contains less than 15 mole % of 1,2-cyclohexanediyl unit units.
• the highly saturated diene elastomer useful for the purposes of the invention can be obtained according to different synthesis methods known to those skilled in the art, in particular depending on the targeted microstructure of the highly saturated diene elastomer. Generally, it can be prepared by copolymerization of at least one 1,3-diene, preferably 1,3-butadiene, and ethylene and according to known synthesis methods, in particular in the presence of a catalytic system comprising a metallocene complex. Mention may be made in this respect of catalytic systems based on metallocene complexes, which catalytic systems are described in documents EP 1 092 731, WO 2004035639, WO 2007054223 and
• the highly saturated diene elastomer can also be prepared by a process using a preformed type catalytic system such as those described in the documents WO 2017093654 Al, WO 2018020122 Al and WO 2018020123 AL Diene elastomer highly saturated is statistical according to one embodiment of the invention.
• the highly saturated diene elastomer useful for the purposes of the invention may consist of a mixture of highly saturated diene elastomers which differ from each other by their microstructures or by their macrostructures.
• the level of highly saturated diene elastomer in the rubber composition is preferably at least 50 parts by weight per hundred parts of elastomer of the rubber composition (phr). More preferably, the level of the highly saturated diene elastomer in the rubber composition varies in a range from 60 to 100 phr, preferably 80 to 100 phr. More preferably, it varies in a range from 90 to 100 pce.
• the elastomer matrix of the composition of the invention may comprise at least one other elastomer, on a minority basis.
• diene elastomers known to those skilled in the art for their use in the field of tires, such as a polybutadiene (abbreviated "BR"), a synthetic polyisoprene (IR), natural rubber (NR), a butadiene copolymer such as a butadiene-styrene copolymer (SBR), an isoprene copolymer and mixtures of these elastomers.
• BR polybutadiene
• IR synthetic polyisoprene
• NR natural rubber
• SBR butadiene copolymer
• SBR butadiene-styrene copolymer
• isoprene copolymer and mixtures of these elastomers.
• composition of the invention comprises a liquid butadiene polymer functionalized at the chain end with an alkoxysilyl function, optionally partially or completely hydrolyzed, having a number average molar mass (Mn) greater than or equal to 1,000 g/mol.
• liquid butadiene polymer according to the invention is meant a more or less viscous butadiene polymer which is liquid at room temperature (approximately 23°C below latm), that is to say, as a reminder, having the ability to eventually take the shape of its container.
• butadiene polymer is meant a homopolymer or a copolymer of butadiene, in other words a diene polymer chosen from the group consisting of polybutadienes, the different butadiene copolymers and mixtures of these polymers.
• a diene polymer chosen from the group consisting of polybutadienes, the different butadiene copolymers and mixtures of these polymers.
• the liquid butadiene polymer is a liquid polybutadiene.
• the liquid butadiene polymer is functionalized at the end of the chain with an alkoxysilyl function, optionally partially or completely hydrolyzed.
• chain-end functionalized polymer is meant a polymer comprising an alkoxysilyl functional group at at least one chain end, that is to say at one end of the main chain of the polymer or at each of the two ends of the main chain of the polymer.
• the liquid butadiene polymer is functionalized with an alkoxysilyl function at each end of the main chain of the polymer, that is to say at both ends of the chain.
• alkoxysilyl function optionally partially or completely hydrolyzed
• each R independently of each other, represents a hydrogen atom or a radical C1-Cio alkyl, preferably C1-C4, or C6-C10 aryl
• each R independently of the others, denotes a C1-C10 alkyl, preferably C1-C4, or Ce-Cio aryl
• n is an integer from 1 to 3, preferably 3.
• the alkoxysilyl function is a function corresponding to the formula - Si(OR)s, R being as defined above, preferably a C1-alkyl C10, preferably still Ci-C4. Even more preferably, the alkoxysilyl function is a trimethoxysilyl or triethoxysilyl function, optionally partially or completely hydrolyzed. According to the invention, the alkoxysilyl function, optionally partially or completely hydrolyzed, is linked to the butadiene polymer by a covalent bond or by a group which may comprise one or more heteroatoms chosen from N and O.
• the liquid butadiene polymer functionalized at the end of the chain with an alkoxysilyl function is a functionalized liquid polybutadiene carrying at each end of the main chain a trialkoxysilyl function, preferably trimethoxysilyl or triethoxysilyl e, the alkoxysilyl functions optionally being able to be partially or totally hydrolyzed.
• the liquid butadiene polymer functionalized at the end of the chain has a number average molar mass (Mn) greater than or equal to 1000 g/mol and preferably less than or equal to 50,000 g/mol, preferably less than or equal at 10,000 g/mol, even more preferably less than or equal to 5,000 g/mol.
• Mn number average molar mass
• the liquid butadiene polymer functionalized at the end of the chain has a number average molar mass (Mn) varying from 1000 g/mol to 5000 g/mol.
• the liquid butadiene polymer functionalized at the end of the chain according to the invention also has a Tg included in a range ranging from -60°C to -100°C, more preferably from -80°C to -100°C. .
• the different preferential characteristics above of the liquid butadiene polymer functionalized at the end of the chain can be combined with each other.
• the liquid butadiene polymer functionalized at the chain end with an alkoxysilyl function can be obtained in a simple and known manner by functionalization of a liquid telechelic polymer of butadiene carrying -OH functions at the chain ends, obtained by radical polymerization, with an agent of alkoxysilane type functionalization capable of reacting with the -OH functions of the polymer. Mention may be made of alkoxysilane compounds carrying an isocyanate function as functionalization agent. Such polymers useful for the purposes of the invention and their synthesis are for example described in document WO2016180649A1.
• the Tg of the liquid polymer is measured by DSC according to standard ASTM D3418 (1999).
• the macrostructure (Mw, Mn and IP) of the liquid polymer is determined by size exclusion chromatography (SEC): solvent tetrahydrofuran; temperature 35°C; concentration 1 g/1; flow rate 1 ml/min; solution filtered on a filter with a porosity of 0.45 ⁇ m before injection; Moore calibration with polystyrene standards; set of 3 “WATERS” columns in series (“STYRAGEL” HR4E, HR1 and HR0.5); detection by differential refractometer ("WATERS 2410") and its associated operating software (“WATERS EMPOWER").
• SEC size exclusion chromatography
• Liquid butadiene polymers useful for the purposes of the invention can be found commercially under the name for example "POLYVEST EP ST-E 60" and “POLYVEST EP ST-E 100" marketed by the company EVONIK.
• the level of liquid butadiene polymer functionalized at each end of the chain with an alkoxysilyl function is advantageously greater than or equal to 0.5 phr, preferably included in a range ranging from 0.5 pce to 25 pce, preferably from 1 to 20 pce, still preferably from 5 pce to 15 pce.
• the liquid butadiene polymer functionalized at each chain end with an alkoxysilyl function may be a mixture of several liquid butadiene polymers functionalized at each chain end with an alkoxysilyl function such as described above.
• the liquid butadiene polymer functionalized at the end of the chain with alkoxysilyl functions, optionally partially or completely hydrolyzed is the only plasticizer in the rubber composition.
• the rubber composition does not include any plasticizer other than the liquid butadiene polymer functionalized at the end of the chain with alkoxysilyl functions, optionally partially or completely hydrolyzed.
• the composition according to the invention comprises a reinforcing filler.
• a reinforcing filler Any type of reinforcing filler known for its capacity to reinforce a rubber composition usable for the manufacture of tires can be used, for example an organic filler such as carbon black, an inorganic reinforcing filler such as silica, alumina, or even a combination of these two types of charge. More particularly, the reinforcing filler comprises at least one silica, one carbon black or a mixture of silica and carbon black.
• All carbon blacks are suitable as carbon blacks, in particular so-called pneumatic grade blacks.
• pneumatic grade blacks we will particularly mention the reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades), such as blacks NI 15, N134, N234, N326, N330, N339, N347, N375, or even, depending on the targeted applications, higher series blacks (e.g. N660, N683, N772).
• the carbon blacks could for example already be incorporated into an isoprene elastomer in the form of a masterbatch (see for example applications 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.
• the composition may contain one type of silica or a blend of several silicas.
• the silica used can be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET surface area as well as a CTAB specific surface area both less than 450 m 2 /g, preferably 30 to 400 m 2 /g.
• HDS highly dispersible precipitated silicas
• the reinforcing filler is mainly an inorganic reinforcing filler (preferably silica), that is to say it comprises more than 50% (>50%) by weight of an inorganic reinforcing filler such as silica relative to the total weight of the reinforcing filler.
• the reinforcing filler also includes carbon black.
• the carbon black is used at a rate less than or equal to 20 pce, more preferably less than or equal to 10 pce (for example the rate of carbon black can be included in a range from 0.5 to 20 pce, notably ranging from 1 to 10 pce). In the indicated intervals, we benefit from the coloring (black pigmentation agent) and anti-UV properties of carbon blacks, without penalizing the typical performances provided by the reinforcing inorganic filler.
• the BET specific surface area is determined by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society” (Vol. 60, page 309, February 1938) , and more precisely according to a method adapted from standard NF ISO 5794-1, appendix E of June 2010 [multi-point volumetric method (5 points) - gas: nitrogen - vacuum degassing: one hour at 160°C - relative pressure range p/in: 0.05 to 0.2],
• CTAB inorganic fillers such as silica
• CTAB specific surface values were determined according to standard NF ISO 5794-1, appendix G of June 2010. The process is based on the adsorption of CTAB (N-bromide). hexadecyl-N,N,N-trimethylammonium) on the “external” surface of the reinforcing filler.
• the physical state in which the reinforcing filler is presented is irrelevant, whether in the form of powder, microbeads, granules, beads or any other suitable densified form.
• the rate of total reinforcing filler is 5 to 150 phr, more preferably 20 to 65 phr. Below 5 pce of load, the composition may not be sufficiently reinforced while above 150 pce of load, the composition could be less efficient in terms of rolling resistance.
• silica is used as the majority filler.
• Silica preferably represents more than 50% by mass of the reinforcing filler.
• the proportion of silica in the reinforcing filler is greater than 50% by weight of the total weight of the reinforcing filler.
• the silica represents more than 85% by mass of the reinforcing filler.
• the silica content varies from 20 phr to 60 phr.
• the carbon black when it is present, is then used in a minority manner, preferably at a rate included in a range ranging from 0.1 to 10 phr, more preferably from 0.5 to 10 phr, in particular from 1 to 10 phr. 5 p.
• an at least bifunctional coupling agent intended to ensure a sufficient connection, of chemical and/or physical nature, between the filler. inorganic (surface of its particles) and diene elastomer.
• at least bifunctional organosilanes or polyorganosiloxanes are used.
• bifunctional is meant a compound having a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the diene elastomer.
• such a bifunctional compound may comprise a first functional group comprising a silicon atom, said first functional group being capable of interacting with the hydroxyl groups of an inorganic charge and a second functional group comprising a sulfur atom, said second functional group capable of interacting with the diene elastomer.
• the organosilanes are chosen from the group consisting of polysulfurized organosilanes (symmetric or asymmetric) such as bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT sold under the name "Si69” by the company Evonik or bis disulfide -(triethoxysilylpropyl), abbreviated TESPD marketed under the name "Si75” by the company Evonik, polyorganosiloxanes, mercaptosilanes, blocked mercaptosilanes, such as "NXT-Silane” or "NXT-Z45 Silane” marketed by the company Momentive .
• TESPT bis(3-triethoxysilylpropyl) tetrasulfide
• TESPD bis(3-triethoxysilylpropyl) tetrasulfide
• TESPD bis(3-triethoxys
• coupling agent is dependent on the quantity of reinforcing inorganic filler to be coupled to the elastomer.
• level of coupling agent represents 0.5% to 15% by weight relative to the quantity of reinforcing inorganic filler, in particular silica.
• composition according to the invention may optionally also contain coupling activators, agents for recovering inorganic charges or more generally agents for aiding implementation capable 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 composition, to improve its ability to be used in the raw state, these agents being known elsewhere.
• the crosslinking system can be any type of system known to those skilled in the art in the field of rubber compositions for tires. It may in particular be based on sulfur, and/or peroxide and/or bismaleimides.
• the crosslinking system is based on sulfur, we then speak of a vulcanization system.
• the sulfur can be provided in any form, in particular in the form of molecular sulfur, or of a sulfur-donating agent.
• At least one vulcanization accelerator is also preferably present, and, optionally, also preferentially, various known vulcanization activators can be used such as zinc oxide, stearic acid or equivalent compound such as stearic acid salts and salts. transition metals, guanidic derivatives (in particular diphenylguanidine), or even known vulcanization retarders.
• Sulfur is used at a preferential rate of between 0.2 pce and 10 pce, more preferably between 0.3 and 5 pce.
• the accelerator or mixture of vulcanization accelerators is used at a preferential rate of between 0.5 and 10 phr, more preferably between 0.5 and 5 phr.
• Any compound capable of acting as an accelerator for the vulcanization of diene elastomers in the presence of sulfur can be used as an accelerator, in particular accelerators of the thiazole type as well as their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. .
• MBTS 2-mercaptobenzothiazyl disulfide
• CBS N-cyclohexyl-2-benzothiazyl sulfenamide
• DCBS N,N-dicyclohexyl- 2-benzothiazyl sulfenamide
• TBBS N-ter-butyl-2-benzothiazyl sulfenamide
• TZTD tetrabenzylthiuram disulfide
• ZBEC zinc dibenzyldithiocarbamate
• the rubber composition according to the invention may optionally also comprise all or part of the usual additives usually used in elastomer compositions for tires, pigments, protective agents such as anti-ozone waxes, chemical antiozonants, anti-oxidants, plasticizers, anti-fatigue agents, reinforcing resins (as described for example in application WO 02/10269).
• protective agents such as anti-ozone waxes, chemical antiozonants, anti-oxidants, plasticizers, anti-fatigue agents, reinforcing resins (as described for example in application WO 02/10269).
• the invention concerns the rubber compositions previously described both in the so-called “raw” or non-crosslinked state (i.e., before cooking) and in the so-called “cooked” or crosslinked state, or even vulcanized ( i.e., after crosslinking or vulcanization).
• composition according to the invention can be manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art:
• thermomechanical mixing (so-called "nonproductive" phase), which can be carried out in a single thermomechanical step during which it is introduced into a suitable mixer such as a usual internal mixer (for example of the 'type Banbury'), all the necessary constituents, in particular the elastomeric matrix, the liquid polybutadiene polymer, the reinforcing filler, any other various additives, with the exception of the crosslinking system.
• a suitable mixer such as a usual internal mixer (for example of the 'type Banbury')
• all the necessary constituents in particular the elastomeric matrix, the liquid polybutadiene polymer, the reinforcing filler, any other various additives, with the exception of the crosslinking system.
• the incorporation of any filler into the elastomer can be carried out one or more times by thermomechanical mixing.
• the filler is already incorporated in whole or in part into the elastomer in the form of a masterbatch as described for example in the applications
• WO 97/36724 or WO 99/16600 it is the masterbatch which is directly kneaded and where appropriate the other elastomers or fillers present in the composition which are not in the form of masterbatch are incorporated, as well as any other miscellaneous additives other than the crosslinking system.
• productive phase a second phase of mechanical work (called "productive" phase), which is carried out in an external mixer such as a roller mixer, after cooling the mixture obtained during the first non-productive phase to a lower temperature, typically less than 120°C.
• the final composition thus obtained is then calendered for example in the form of a sheet or a plate, in particular for characterization in the laboratory, or even extradited (or co-extradited with another rubber composition) in the form of a semi-finished (or profile) of rubber usable in a tire, for example as a tread.
• These products can then be used for the manufacture of tires, according to techniques known to those skilled in the art.
• the composition can be either in the raw state (before crosslinking or vulcanization), or in the cooked state (after crosslinking or vulcanization), and can be a semi-finished product which can be used in a tire.
• the crosslinking (or cooking), where appropriate the vulcanization, is carried out in a known manner at a temperature generally between 130°C and 200°C, for a sufficient time which can vary for example between 5 and 90 min depending in particular on the cooking temperature, the crosslinking system adopted and the crosslinking kinetics of the composition considered. 7 Pneumatic
• the present invention also relates to a pneumatic or non-pneumatic tire comprising a rubber composition according to the invention.
• the microstructure of the elastomers is determined by 1 H NMR analysis, supplemented by 13 C NMR analysis when the resolution of the X H NMR spectra does not allow the attribution and quantification of all the species.
• the measurements are carried out using a BRUKER 500MHz NMR spectrometer at frequencies of 500.43 MHz for proton observation and 125.83 MHz for carbon observation.
• a HRMAS 4mm z-grad probe is used to observe the proton and carbon in decoupled mode from the proton.
• the spectra are acquired at rotation speeds of 4000Hz to 5000Hz.
• a liquid NMR probe is used to observe the proton and carbon in decoupled mode from the proton.
• the soluble samples are dissolved in a deuterated solvent (approximately 25 mg of elastomer in ImL), generally deuterated chloroform (CDCL).
• a deuterated solvent approximately 25 mg of elastomer in ImL
• CDCL generally deuterated chloroform
• the solvent or solvent blend used must always be deuterated and its chemical nature can be adapted by those skilled in the art.
• a single pulse sequence of 30° is used.
• the spectral window is adjusted to observe all of the resonance lines belonging to the molecules analyzed.
• the accumulation number is adjusted to obtain a sufficient signal-to-noise ratio for the quantification of each pattern.
• the recycling delay between each pulse is adapted to obtain a quantitative measurement.
• a single pulse 30° sequence is used with proton decoupling only during acquisition to avoid "Nuclear Overhauser” effects (NOE) and remain quantitative.
• the spectral window is adjusted to observe all of the resonance lines belonging to the analyzed molecules.
• the accumulation number is adjusted to obtain a sufficient signal-to-noise ratio for the quantification of each pattern.
• the recycling delay between each pulse is adapted to obtain a quantitative measurement.
• Tg glass transition temperature
• the dynamic properties G* (25%) and tanômax (25%) at 60°C are measured on a viscoanalyzer (Metravib VA4000), according to the ASTM D 5992-96 standard.
• the response of a sample of reticulated composition (cylindrical test piece 4 mm thick and 400 mm2 in section) is recorded, subjected to a sinusoidal stress in alternating simple shear, at a frequency of 10 Hz, under defined temperature conditions. for example at 60°C according to standard ASTM D 1349-99.
• a deformation amplitude sweep is carried out from 0.1 to 100% (forward cycle), then from 100% to 0.1% (return cycle).
• the results used are the complex dynamic shear modulus G* and the loss factor tan(ô).
• tan(ô) max at 25% deformation observed at 60°C denoted tanômax (25%), as well as the complex dynamic shear modulus G* at 25% deformation, at 60°C.
• the tanômax measurement (25%) is a descriptor of hysteresis and therefore an indication of the rolling resistance property of the tire.
• the value in base 100 is calculated according to the operation: (tanômax value (25%) at 60°C of the control / tanômax value (25%) at 60°C of the sample) * 100.
• a lower value than the control represents a decrease in hysteresis performance (i.e. an increase in hysteresis) while a higher value represents a better hysteresis performance (i.e. say lower hysteresis).
• the G* measurement (25%) is a stiffness descriptor and therefore an indication of the tire's wear resistance property of the tire.
• the value in base 100 is calculated according to the operation: (value of G* (25%) at 60°C of the sample / value of G* (25%) at 60°C of the control) * 100. From this way, a value lower than the control represents a decrease in stiffness, while a higher value represents greater stiffness.
• the elastomer is introduced into an internal mixer (final filling rate: approximately 70% by volume), whose initial tank temperature is approximately 90°C. When the temperature reaches 100°C, the liquid butadiene polymer, silica, carbon black and coupling agent are introduced, as well as the various other ingredients with the exception of sulfur and vulcanization accelerators. Thermomechanical work is then carried out (non-productive phase) in one step, which lasts in total around 3 to 4 min, until a maximum "drop" temperature of 160°C is reached. The mixture thus obtained is recovered, cooled and then the sulfur and the vulcanization accelerators are incorporated on a cylinder tool at 25°C, mixing everything (productive phase) for an appropriate time (for example 5 minutes).
• compositions thus obtained are then calendered either in the form of plates (thickness 2 to 3 mm) or thin sheets of rubber for the measurement of their physical or mechanical properties.
• the crosslinking was then carried out at a temperature of 150°C, under pressure.
• El elastomer is a highly saturated diene elastomer, a copolymer of ethylene and 1,3-butadiene prepared according to the following procedure:
• the reactor is supplied throughout the polymerization with ethylene and 1,3-butadiene in the molar proportions 73/27.
• the polymerization reaction is stopped by cooling, degassing the reactor and adding ethanol.
• An antioxidant is added to the polymer solution.
• the copolymer is recovered after stripping with steam and drying to constant mass.
• the polymerization time is 225 minutes.
• the weighed mass (6,206 kg) makes it possible to determine the average catalytic activity of the catalytic system expressed in kilogram of polymer synthesized per mole of neodymium metal and per hour (kg/mol.h).
• the copolymer has an ML value equal to 62.
• the catalyst system is a preformed catalyst system. It is prepared in methylcyclohexane from a metallocene, [Me2Si(Flu)2Nd(p-BH4)2Li(THF)] at 0.0065 mol/L, from a co-catalyst, butyloctylmagnesium (BOMAG) whose BOMAG/Nd molar ratio is equal to 2.2, and a preformation monomer, 1,3-butadiene whose 1,3-butadiene/Nd molar ratio is equal to 90. The medium is heated to 80°C on a duration of 5 hours. It is prepared according to a preparation method in accordance with paragraph II.1 of patent application WO 2017093654 AL
• composition according to the invention with an elastomeric matrix based on an EBR and a liquid polybutadiene functionalized at each chain end with an alkoxysilyl function, makes it possible to significantly improve the hysteresis performance ( reduction in hysteresis) and rigidity in comparison with a composition not comprising liquid polybutadiene.
• This effect is observed against all expectations since the joint use of an EBR and a non-functionalized liquid polybutadiene degrades these two properties.

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