Classifications

• • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08C—TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
  • C08C19/00—Chemical modification of rubber
  • C08C19/25—Incorporating silicon atoms into the molecule
• • 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
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F36/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
• • 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
  • C08F4/00—Polymerisation catalysts
  • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
  • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
  • C08F4/46—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides selected from alkali metals
  • C08F4/48—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides selected from alkali metals selected from lithium, rubidium, caesium or francium
  • C08F4/482—Metallic lithium, rubidium, caesium or francium
• • 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
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L19/00—Compositions of rubbers not provided for in groups C08L7/00 - C08L17/00
  • C08L19/006—Rubber characterised by functional groups, e.g. telechelic diene polymers
• • 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
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/06—Ethers; Acetals; Ketals; Ortho-esters
• • 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
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/17—Amines; Quaternary ammonium compounds

Definitions

• the present invention relates to a monomodal diene elastomer coupled having a silanol function in the middle of a chain, to a process for the preparation of this elastomer, and to a rubber composition that can be used in particular for the manufacture of tire casings, having improved hysteretic and physical properties in the vulcanized state as well as improved raw-state processing, comprising a monomodal diene polymer having a mid-chain silanol function and a reinforcing inorganic filler.
• rubber compounds which can be used for the manufacture of various semi-finished products forming tire casings such as, for example, underlays, bonding compounds between rubbers of different kinds or coating metallic or textile reinforcements, sidewall compounds or treads and obtain tires with improved properties, including reduced rolling resistance.
• EP-A-0 299 074 and EP-A-0 447 066 disclose functionalized polymers having alkoxysilane functions. These functionalized polymers have been described in the prior art as being effective in reducing hysteresis and improving abrasion resistance, however, their properties are still insufficient to allow the use of these polymers in compositions intended to form strips of adhesive. tire rolling. Moreover, the formulation of these polymers poses problems of evolution of the macrostructures during the removal of the polymerization solvent, which leads to a severe degradation of the potentially interesting properties. In addition, this evolution is very little controllable.
• patent application EP-A-0 877 047 has described a rubber composition using as reinforcing filler carbon black having silica fixed on its surface, based on a diene polymer functionalized at the chain end by a silanol function or a polysiloxane block having at least one silanol end or a functionalized diene polymer along its chain with silanol functions.
• This composition has improved hysteresis properties over compositions containing carbon black as a reinforcing filler.
• said composition is delicate due to the high Mooney viscosity of the raw mixture.
• Patent applications EP 1 398 347 A1, EP 1 400 559 A1, EP 1 400 560 A1 disclose the use of rubber compositions usable for the manufacture of tire casings comprising a polymodal and preferably bimodal composite SBR having at least a SiOH or SiOR function in the middle of the chain marketed by Japan Synthetic Rubber Corporation under the trademark T596.
• This polymodal composite SBR comprises 35 to 55% by weight of a non-functional SBR1 with a number-average molecular weight Mn ranging from 200,000 to 300,000 g / mol and from 65 to 35% by weight of an SBR2 having a number-average molecular weight Mn ranging from 400,000 to 500,000 g / mol, a styrene content ranging from 25 to 35% and a content of 1,2 units for the butadiene part ranging from 50 to 70% (a glass transition temperature Tg ranging from -15 ° C. at -30 ° C.) and from 0 to 10% by weight of an SBR3 having a number-average molecular weight greater than 550,000 g / mol.
• the elastomers usable in a crosslinkable rubber composition for use in a tire are mainly butadiene and styrene copolymers (SBR) or polybutadienes (BR). Their synthesis requires the use of a polar agent during the polymerization step to allow the adjustment of the glass transition temperature.
• SBR styrene copolymers
• BR polybutadienes
• polar agents may be used, among which non-chelating polar agents of THF type and polar chelating agents having on at least two atoms at least one non-binder doublet, for example of the tetrahydrofurfuryl ethyl ether or tetramethylethylenediamine type.
• the present invention relates, as a new industrial product, to a coupled diene elastomer having a mid-chain silanol function, an overall Si function rate T, which is the ratio N / N p , in which N s is the number of moles of silicon bound to the coupled polymer determined by 1 H NMR nuclear magnetic resonance and expressed in mmol / kg, N p represents the number of mmoles of polymer before coupling per kilogram of polymer, ranging from 0.36 to 0.60 (ie one function rate Si ranging from 36% to 60%), a silanol (SiOH) function level in the middle of the chain T1, which is the ratio corresponding to the number of moles of SiOH functions over the number of moles of Si (Si), determined by 1 H- 29 Si NMR2D nuclear magnetic resonance ranging from 80 to 100% and a monomodal distribution of the number-average molecular weights of the coupled polymer chains.
• N s is the number of moles of silicon bound to the coupled polymer determined by 1
• the present invention also relates to a process for obtaining a monomodal diene elastomer coupled having a mid-chain silanol functional group comprising, in a first step, reacting the monomer (s), in the presence or absence of an inert hydrocarbon solvent, in the presence of a chelating polar agent having at least two at least one non-binder doublet, with a polymerization initiator, to form a living diene polymer and to react, in a second step, as known per se, said living polymer with a polymer chain coupling agent to obtain, after hydrolysis, the monomodal diene polymer coupled having a silanol function in the middle of the chain.
• elastomer or monomodal polymer means, in relation to the distribution of molecular weights, a molecular weight distribution in number determined by SEC (size exclusion chromatography) corresponding to a single peak during the decomposition of the SEC chromatogram.
• the nature of the polar agent employed during the polymerization step has an influence on the selectivity of the coupling reaction between the living polymer chains and the polymer chain coupling agent.
• T-rate is high, that is to say ranging from 0.36 to 0.60, which shows that the majority of the polymer chains comprising an Si atom are coupled, knowing that the optimum of the coupling reaction consists in having two polymer chains coupled to an Si atom, which corresponds to a Si function rate of 0.5, and on the other hand that it forms very predominantly (functionalization ratio T1> 80%, that is to say ranging from 80 to 100%), coupled elastomers having a mid-chain silanol functionality due to a very high selectivity of said chelating polar agent and that the number-average molecular weight distribution of
• agents comprising at least one tertiary amine function or at least one ether function and preferably tetrahydrofurfuryl ethyl ether or tetramethyl ethylenediamine agents are particularly suitable.
• 1,3-butadiene, 2-methyl-1,3-butadiene and 2,3-di (C 1 to C 5 alkyl) are particularly suitable.
• 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, 2 methyl-3-isopropyl-1,3-butadiene, phenyl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene, etc.
• vinylaromatic compounds are especially suitable styrene, ortho-, meta, para-methylstyrene, the commercial mixture "vinyltoluene", para-tert-butylstyrene, methoxystyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, etc.
• the copolymers may contain from 99% to 20% by weight of diene units and from 1% to 80% by weight of vinylaromatic units.
• Coupled monomodal diene polymers carrying a silanol function in the middle may have any microstructure which is a function of the polymerization conditions used.
• the polymers can be block, statistical, sequence, microsequencer, etc. and be prepared in dispersion or solution.
• the microstructure of these polymers may be determined by the presence or absence of a modifying and / or randomizing agent and the amounts of modifying and / or randomizing agent employed.
• coupled monomodal diene polymers capable of being prepared according to the process according to the invention, is meant any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms, any copolymer obtained by copolymerization of one or more conjugated dienes with each other or with one or more vinylaromatic compounds having from 8 to 20 carbon atoms.
• the monomodal diene polymer coupled carrying a silanol function in the middle of the chain is chosen from the group of "highly unsaturated" diene elastomers prepared in solution consisting of polybutadienes (BR), synthetic polyisoprenes (IR), butadiene-styrene copolymers (SBR), butadiene-isoprene copolymers (BIR), isoprene-styrene copolymers (SIR), butadiene-styrene-isoprene copolymers (SBIR).
• BR polybutadienes
• IR synthetic polyisoprenes
• SBR butadiene-styrene copolymers
• BIR butadiene-isoprene copolymers
• SIR isoprene-styrene copolymers
• SBIR butadiene-styrene-isoprene copolymers
• said elastomer belongs to the family consisting of polybutadienes, butadiene-styrene copolymers and butadiene-styrene-isoprene copolymers prepared in solution and polyisoprene.
• said elastomer is a butadiene-styrene copolymer prepared in solution.
• said elastomer is a butadiene-styrene copolymer prepared in solution having a styrene content of between 20% and 45% by weight, a vinyl bond content of the butadiene part of between 15% and 65%, a bond content of trans-1,4, between 15% and 75% and a Tg between -5 and -65 0 C, and preferably between -20 and -55 0 C.
• Polybutadienes and in particular those having a content of 1,2-units of between 15% and 80%, polyisoprenes and copolymers of butadiene-styrene, and in particular those having a styrene content of between 4 and 50, are particularly suitable. % by weight and more particularly between 20% and 40% by weight, a 1,2-butadiene content of the butadiene part of between 15% and 65%, a content of trans-1,4 bonds of between 10% and 80%.
• Tg transition temperature glass
• butadiene-styrene-isoprene copolymers those having a styrene content of between 5 and 50% by weight and more particularly of between 10% and 40%, and isoprene of between 15% and 60% by weight, and more particularly between 20% and 50% by weight, a butadiene content of between 5 and 50% and more particularly of between 20% and 40% by weight, a 1,2-unit content of the butadiene part of between 15% and 50% by weight.
• trans-1,4 units content of the butadiene part of between 6% and 80%, a content of 1,2-units plus 3,4 of the isoprenic part of between 15% and 70% and a trans-1,4 units content of the isoprenic part of between 10% and 50% and more generally butadiene-styrene-isoprene copolymer having a Tg between -5 ° C. and -70 ° C.
• any known monofunctional anionic initiator can be used.
• an initiator containing an alkali metal such as lithium is used in a preferred manner.
• Suitable organolithium initiators include those having a carbon-lithium bond. Representative compounds are aliphatic organoliths such as ethyllithium, n-butyllithium (n-BuLi), isobutyl lithium, etc., lithium amides which are obtained from a cyclic secondary amine, such as pyrrolidine. and hexamethyleneimine and which are soluble in a hydrocarbon solvent without the use of a solvating agent are highly preferred.
• the polymerization is, as known per se, preferably carried out in the presence of an inert hydrocarbon solvent which may be for example an aliphatic or alicyclic hydrocarbon such as pentane, hexane, heptane, isooctane, cyclohexane , methylcyclohexane or an aromatic hydrocarbon such as benzene, toluene, xylene.
• an inert hydrocarbon solvent which may be for example an aliphatic or alicyclic hydrocarbon such as pentane, hexane, heptane, isooctane, cyclohexane , methylcyclohexane or an aromatic hydrocarbon such as benzene, toluene, xylene.
• the polymerization can be carried out continuously or discontinuously.
• the polymerization is generally carried out at a temperature of between 20 ° C. and 150 ° C. and preferably in the region of 30 ° C. to 110 ° C.
• the coupling reaction of the living diene polymer obtained at the end of the first step can be carried out at a temperature of between -20 and 100 ° C., by adding a non-polymerizable coupling agent to the living polymer chains or Conversely.
• the mixing can be carried out by any appropriate means, in particular with the aid of any mixer having static agitation and / or any dynamic stirrer of the perfectly stirred type known to those skilled in the art.
• the reaction time between the living diene polymer and the coupling agent can be between 10 seconds and 2 hours.
• Suitable coupling agents are all compounds having the formula RSiX n wherein R represents a primary or secondary alkyl, cycloalkyl, aryl group having from 1 to 20 carbon atoms, and X represents a halogen atom and a preferably chlorine or bromine, n is the integer 3.
• the ratio for the coupling between the coupling agent RSiX n and the metal of the initiator of the living polymer chains is between 0.4 and 1.0 and preferentially between 0.5 and 0.7.
• the solvent used for the coupling reaction of the polymer chains preferably, is the same as the inert hydrocarbon solvent used for the polymerization, and preferably cyclohexane or any other aliphatic hydrocarbon solvent.
• the mass ratio solvent / monomer (s) before the reaction will be between 1 and 15 and preferably between 4 and 7.
• the polymerization process may be carried out in a continuous or batch process.
• the diene coupled polymers which possess in the middle of a chain a silanol functional group and prepared according to the process according to the invention have a number average molecular weight Mn determined by the conventional SEC technique of between 100,000 g / mol and 350,000 g / mol. and preferably between 1 14 000 and 185 000 g / mol.
• the Mooney viscosity (ML1 +4 at 100 ° C.) will preferably be between 20 and 1 50.
• the coupled diene polymers which have a silanol function in the middle of the chain and are prepared according to the process according to the invention are recovered according to the conventional methods of recovery, in particular by hot drying and / or reduced pressure or by stripping.
• the object of the invention is also to provide a crosslinkable or crosslinked rubber composition based on at least one or more monomodal diene polymer (s) coupled having a silanol function in the middle of the chain.
• Si global T which is the ratio N / N p , in which N s represents the number of moles of silicon bound to the coupled polymer determined by 1 H NMR and expressed in mmol / kg, N p represents the number of moles of polymer before coupling per kilogram of polymer, ranging from 0.36 to 0.60 (ie a functional level Si ranging from 36% to 60%), a silanol (SiOH) functional level in the middle of the chain T1 determined by NMR2D'H- 29 Si nuclear magnetic resonance ranging from 80 to 100% and a monomodal distribution of number-average molecular weights of the coupled polymer chains, and a reinforcing inorganic filler which exhibits reduced hysteretic losses in the cross-linked state and improved workability in the uncrosslinked state and which has
• a crosslinked rubber composition obtained by the combination with a reinforcing inorganic filler of at least one coupled monomodal diene elastomer according to the invention which comprises a silanol function in the middle of the chain, an overall Si function rate T, which is the ratio N / N p , in which N s represents the number of moles of silicon bound to the coupled polymer determined by 1 H NMR and expressed in mmol / kg, N p represents the number of moles of polymer before coupling per kilogram of polymer, ranging from 0.36 to 0.60 (ie a function rate Si ranging from 36% to 60%), a function rate silanol (SiOH) in the middle of the chain T1 determined by nuclear magnetic resonance NMR2D'H- 29 Si ranging from 80 to 100% and a monomodal distribution of the number-average molecular masses of the coupled polymer chains, for example obtained the process of preparation described above, exhibits reduced hysteretic losses at small
• the characteristics of the coupled monomodal diene elastomer comprising a silanol function in the middle of the chain, an overall (Si) functional level T ranging from 0.36 to 0.60 and a silanol (SiOH) function level in the middle chain T1 ranging from 80 to 100%, according to the invention make it usable to form a rubber composition advantageously usable as a tire tread having in particular a reduced rolling resistance for new tire or retreaded or as an internal mixture to the tire, for example for the production of underlays, for the calendering of crown reinforcements or carcasses.
• the subject of the invention is also a tire comprising a tread based on a rubber composition based on at least one monomodal diene polymer coupled according to the invention having a silanol function in the middle of the chain, a function ratio If global T, which is the ratio N / N p , in which N s represents the number of moles of silicon bound to the coupled polymer determined by 1 H NMR and expressed in mmol / kg, N p represents the number of moles of polymer before coupling per kilogram of polymer, ranging from 0.36 to 0.60 (ie a functional level Si ranging from 36% to 60%), a resonance-determined silanol (SiOH) function level in the chain of T1 NMR2D'H- 29 Si nuclear magnetic resonance ranging from 80 to 100% and a monomodal distribution of number-average molecular weights of the coupled polymer chains, and a reinforcing inorganic filler.
• T which is the ratio N / N p , in which N s represents the number of
• said composition is based on an elastomer matrix comprising predominantly at least one monomodal diene elastomer coupled having a silanol function in the middle of the chain, an overall Si function rate T, which is the ratio N / N p , in which N 5 represents the number of moles of silicon bound to the coupled polymer determined by 1 H NMR and expressed in mmol / kg, N p is the number of moles of polymer before coupling per kilogram of polymer, ranging from 0.36 to 0.60 (ie a functional level Si ranging from 36% to 60%), a silanol (SiOH) function level in the middle of the chain T1 determined by nuclear magnetic resonance NMR2D'H- 29 If ranging from 80 to 100% and a monomodal distribution of the number of molecular weights of the coupled polymer chains, even more preferably, this elastomer matrix consists exclusively of termed monomodal diene elastomer having a silanol function in the middle of the chain, an overall Si function rate
• composition based on is meant a composition comprising the mixture and / or the reaction product in situ of the various constituents used, some of these basic constituents being capable of or intended to react with each other, at least in part, during the various phases of manufacture of the composition, in particular during its crosslinking.
• compositions according to the invention may contain a single coupled monomodal diene elastomer having a silanol function in the middle of the chain, an overall Si function rate T, which is the ratio N / N p / in which N s represents the number of moles of silicon bound to the coupled polymer determined by nuclear magnetic resonance NMRH and expressed in mmol / kg, N p represents the number of moles of polymer before coupling per kilogram of polymer ranging from 0.36 to 0.60 (ie a Si function level ranging from 36% to 60%), a silanol (SiOH) functional level in the T1 chain medium determined by NMR2D'H- 29 Si nuclear magnetic resonance ranging from 80 to 100% and a monomodal mass distribution.
• T is the ratio N / N p / in which N s represents the number of moles of silicon bound to the coupled polymer determined by nuclear magnetic resonance NMRH and expressed in mmol / kg, N p represents the number of moles of polymer before coupling per kilogram of poly
• the monomodal diene monomer (s) having the silanol function at the middle of the chain, an overall Si function rate T, which is the ratio N / N p , in which N 5 represents the number of moles of silicon bound to the coupled polymer determined by 1 H NMR nuclear magnetic resonance and expressed in mmol / kg, N p represents the number of moles of polymer before coupling per kilogram of polymer, ranging from 0.36 to 0.60 (ie a Si function rate ranging from 36% to 60%), a silanol (SiOH) functional level in the T1 chain medium determined by 1 H- 29 Si NMR2D nuclear magnetic resonance ranging from 80 to 100% and a monomodal distribution number-average molecular weights of the coupled polymer chains, according to the invention may be used alone in the composition according to the invention or in blending with any other functionalized or non-functional diene elastomer which is conventional
• this inorganic filler being able to reinforce on its own, without any other means than an intermediate coupling agent, a rubber composition intended for the manufacture of tires, in particular other terms capable of replacing, in its reinforcing function, a conventional load of pneumatic grade carbon black.
• a charge is generally characterized, in known manner, by the presence of hydroxyl groups (-OH) on its surface, thereby requiring the use of an agent or coupling system intended to ensure a stable bond between the elastomer and load.
• the reinforcing inorganic filler is present in the composition of the invention in an amount of between 20 and 200 phr. [phr: parts by weight per hundred parts of elastomer (s)], more preferably between 40 and 150 phr, the optimum being different depending on the intended applications. Also preferably, said reinforcing inorganic filler is present in the reinforcing filler that comprises the composition of the invention in a mass fraction greater than 50% and up to 100%.
• said reinforcing inorganic filler is, wholly or at least predominantly, silica (SiO).
• 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 mVg, even if the highly dispersible precipitated silicas are preferred.
• the BET surface area is determined in a known manner, according to the method of Brunauer-Emmet-Teller described in "The Journal of the American Chemical Society” Vol. 60, page 309, February 1938 and corresponding to standard AFNOR-NFT-45007 (November 1987); the CTAB surface area is the external surface determined according to the same standard AFNOR-NFT-45007 of November 1987.
• highly dispersible silica any silica having a very important ability to deagglomeration and dispersion in an elastomeric matrix, observable in known manner by electron or optical microscopy, thin sections.
• preferential highly dispersible silicas include Perkasil KS 430 silica from Akzo, BV 3380 silica from Degussa, Zeosil 1165 MP, 1135 MP and 1115 MP from Rhodia, Hi-SiI 2000 and Hi-SiI EZ 150G silica from PPG, the Zeopol 8715, 8755 or 8745 silicas of the Huber Company as described in application WO 03/016387, treated precipitated silicas, such as, for example, silicas, doped with aluminum described in EP-A-735 088.
• the physical state in which the reinforcing inorganic filler is present is indifferent, whether in the form of powder, microbeads, granules, or beads.
• the term reinforcing inorganic filler is also understood to mean mixtures of different reinforcing inorganic fillers, in particular highly dispersible silica as described above.
• As a reinforcing inorganic filler also highly dispersible alumina (Al 2 O 3 ) having a BET surface area ranging from 30 to 400 m 2 / g, more preferably from 60 to 250 m 2 / g, an average particle size, is suitable. at most equal to 500 nm, more preferably at most equal to 200 nm.
• aluminas As non-limiting examples of such reinforcing aluminas, there may be mentioned the aluminas “Baikalox A125” or “CR125” (Baikowski Company), “APA-100RDX” (Condea), “Aluminoxid C” (Degussa) or “AKP-G015" (Sumitomo Chemicals).
• the reinforcing filler of a rubber composition according to the invention may contain, in addition to the abovementioned reinforcing inorganic filler (s), carbon black as a minority (that is to say at a mass fraction of less than 50%) or inert (non-reinforcing) fillers.
• Suitable carbon blacks are all carbon blacks, especially blacks of the HAF, ISAF, SAF type conventionally used in tires and particularly in tire treads.
• blacks N115, N134, N234, N339, N347, N375 there may be mentioned blacks N115, N134, N234, N339, N347, N375.
• Inert, non-reinforcing fillers are suitable for particles of clay, bentonite, talc, chalk, kaolin.
• black / silica or partially or fully silica-coated blacks are suitable for forming the reinforcing filler.
• Reinforcing fillers comprising carbon blacks covered at least in part by an inorganic layer, for example silica, which in turn require the use of a coupling agent to establish the bond with the elastomer, such as, for example, without limitation, the charges which are marketed by CABOT under the name "CRX 2000", and which are described in patent document WO-A-96/37547.
• aluminas of formula Al 2 O 3
• high dispersibility aluminas which are described in European patent document EP-A-810 258.
• further aluminum hydroxides such as those described in WO-A-99/28376.
• the mass fraction of this carbon black in said reinforcing filler is preferably chosen less than or equal to 30%.
• the rubber composition according to the invention further comprises, in a conventional manner, a reinforcing inorganic filler / elastomer matrix.
• binding agent is more specifically meant an agent capable of establishing a sufficient chemical and / or physical connection between the charge in question and the elastomer, while facilitating the dispersion of this charge within the elastomeric matrix.
• a binding agent at least bifunctional, has for example as simplified general formula "Y-T-X", in which:
• Y represents a functional group ("Y" function) which is capable of binding physically and / or chemically to the inorganic filler, such a bond being able to be established, for example, between a silicon atom of the coupling agent and the hydroxyl (OH) groups of the surface of the inorganic filler (for example the surface silanols when it is silica);
• X represents a functional group ("X" function) capable of bonding physically and / or chemically to the elastomer, for example via a sulfur atom;
• T represents a divalent group making it possible to connect Y and X.
• the bonding agents should not be confused with simple charge-covering agents considered which, in a known manner, may comprise the active Y function with respect to the charge but lack the active X function vis-à-vis the load -vis the elastomer.
• Any binding agent known for, or capable of effectively ensuring, in the tire rubber compositions used for the manufacture of tires, the bonding (or coupling) between an inorganic reinforcing filler such as silica and a diene elastomer may be used.
• organosilanes especially polysulfurized alkoxysilanes or mercaptosilanes, or else polyorganosiloxanes bearing the aforementioned X and Y functions.
• Silica / elastomer bonding agents in particular, have been described in a large number of documents, the best known of which are bifunctional alkoxysilanes such as polysulfurized alkoxysilanes.
• polysulphurized alkoxysilanes known as “symmetrical” or “asymmetric” according to their particular structure, are used, as described, for example, in US-A-3,842,111, US-A-3,873,489, US-A. No. 3,978,103, US-A-3,997,581, US-A-4,002,594, US-A-4,072,701, US-A-4,129,585, or in newer patents US-A-5,580,919.
• N is an integer of 2 to 8 (preferably 2 to 5);
• A is a divalent hydrocarbon radical (preferably C 1 -C 18 alkylene groups or C 6 -C 12 arylene groups, more particularly C 1 -C 10 alkylenes, in particular C 1 -C 4 alkylenes, in particular propylene);
• n is a fractional number, preferably ranging from 2 to 5 and more preferably close to 4.
• polysulfides especially disulfides, trisulphides or tetrasulfides
• bis- (alkoxy (C r C 4 ) - alkyl (C 1 -C 4 ) silylalkyl (C 1 -C 4 ) such as, for example, bis (3-trimethoxysilylpropyl) or bis (3-triethoxysilylpropyl) polysulfides.
• TESPT bis (3-triethoxysilylpropyl), abbreviated TESPT, of formula [(C 2 H 5 O) 3 Si (CH j) 3 S 2].
• the TESPD is marketed for example by the company Degussa under the names Si266 or Si75 (in the second case, under form of a mixture of disulfide (75% by weight) and polysulfides), or by the company Witco under the name Silquest A1589 TESPT is marketed for example by the company Degussa under the name Si69 (or X50S when it is supported at 50% by weight on carbon black), or by the company Osi Specialties under the name Silquest A1289 (in both cases, a commercial mixture of polysulfides with a mean value for n which is close to 4).
• Polysulfides (especially disulfides, trisulfides or tetrasulfides) of bis- (mon oalkoxyl (C 1 -C 4) -dialkyl (C, -C 4) silylpropyl), particularly tetrasulfide or disulfide bis-monoethoxydimethylsilylpropyl (abbreviated MESPT), which are the subject of the international patent application WO 02 / 083782 (or US 2004/0132880) on behalf of the applicants.
• MESPT tetrasulfide or disulfide bis-monoethoxydimethylsilylpropyl
• the level of coupling agent is advantageously less than 20 phr, and preferably less than 10 phr, it being understood that it is generally desirable to use as little as possible and adjusted to the amount of reinforcing inorganic filler.
• compositions according to the invention also comprise, besides said monomodal diene elastomer coupled having a silanol function in the middle of the chain, an overall Si function rate T, which is the ratio N / N p , in which N s represents the number of moles of silicon bound to the coupled polymer determined by 1 H NMR nuclear magnetic resonance and expressed in mmol / kg, N represents the number of moles of polymer before coupling per kilogram of polymer, ranging from 0.36 to 0.60 (ie a function rate Si ranging from 36% to 60%), a silanol (SiOH) function level in the middle of the chain T1 determined by NMR2D'H- 29 Si nuclear magnetic resonance ranging from 80 to 100% and a monomodal distribution of the number of molecular weights of the coupled polymer chains, and said reinforcing inorganic filler, plasticizers, pigments, antioxidants, anti-fatigue agents, anti-ozonating waxes, adhesion promoters, reinforcing or plasticizing resins
• compositions may be such that said coupled monomodal diene elastomer having a silanol function in the middle of the chain, an overall Si function rate T, which is the ratio N / N p , in which N 5 represents the number of moles of silicon coupled to the coupled polymer determined by 1 H NMR and expressed in mmol / kg, N p represents the number of moles of polymer before coupling per kilogram of polymer, ranging from 0.36 to 0.60 (a ratio of Si function ranging from 36% to 60%), a silanol (SiOH) function level in the T1 chain medium determined by NMR2D'H- 29 Si nuclear magnetic resonance ranging from 80 to 100% and a monomodal distribution of molecular masses by number coupled polymer chains, is extended to an aromatic or nonaromatic or very weakly aromatic oil, selected from the group consisting of a paraffinic oil, naphthenic, MES oil, TDAE oil, ester glycerol, the hydrocarbon plasticizing resins having a high T
• thermomechanical working time (i) the production, at a maximum temperature of between 130 ° C. and 200 ° C., of a first thermomechanical working time (sometimes qualified as phase
• Non-productive of the necessary basic constituents, with the exception of the crosslinking system, of said composition comprising said coupled monomodal diene elastomer having a mid-chain silanol function, an overall Si function rate T, which is the ratio N / N p , in which N 5 represents the number of moles of silicon bound to the coupled polymer determined by 1 H NMR and expressed in mmol / kg, N p is the number of moles of polymer before coupling per kilogram of polymer , ranging from 0.36 to 0.60 (ie a functional level Si ranging from 36% to 60%), a silanol (SiOH) function level in the middle of the chain T1 determined by nuclear magnetic resonance NMR2D'H- 29 Si ranging from 80 to 100% and a monomodal distribution of the number of molecular weights of the coupled polymer chains, and a reinforcing inorganic filler, with the exception of a crosslinking system, and then
• This process may also comprise the preparation of a monomodal diene elastomer coupled having a silanol function in the middle of the chain, an overall Si function rate T, which is the ratio N / N p , in which N 5 represents the number of moles of silicon coupled to the coupled polymer determined by 1 H NMR and expressed in mmol / kg, N p represents the number of moles of polymer before coupling per kilogram of polymer, ranging from 0.36 to 0.60 (a ratio of If function ranging from 36% to 60%), a function rate silanol (SiOH) in the middle of the chain T1 determined by nuclear magnetic resonance NMR2D'H- 29 Si ranging from 80 to 100% and a monomodal distribution of the number-average molecular weights of the coupled polymer chains, consisting, in a first step, in making reacting the monomer (s) in the presence or absence of an inert hydrocarbon solvent in the presence of a chelating polar agent having at least two atoms at least one non-binder
• the invention also relates to a tire tread which is such that it comprises a crosslinkable or crosslinked rubber composition such as that mentioned above, or which is such that it consists of this composition.
• a tire according to the invention is such that it comprises this tread.
• FIGS. 1 to 6 show the molecular weight distributions in weight Mi determined by the SEC technique, respectively copolymers A, B, E, F, G, H according to the invention.
• the X axis represents in decimal logarithmic form a scale of the molecular weights (Mi) in g / mole of the polymers; the Y-axis represents an arbitrary scale proportional to the weight of the number-average molecular weight polymer (Mi).
• EXAMPLE 1 Synthesis of SBR in a Batch Mode
• Coupled copolymer B prepared in the presence of a non-chelating polar agent
• a "control" bottle of 0.25 l maintained under nitrogen and in another identical bottle intended for the implementation of the invention 105 grams of cyclohexane (135 ml), butadiene and styrene, are introduced according to the respective weight ratios 1 / 0.091 / 0.051. 22 ppm of tetrahydrofurfuryl ethyl ether is also introduced as a vinyl-link promoter. After neutralization of the impurities using n-butyllithium (n-BuLi), 123 ⁇ mol of n-butyl lithium is added. The polymerization is conducted in each of the two bottles at 40 ° C., and the converted monomer content is 76% after 100 min. This level is determined by weighing an extract dried at 110 ° C. under the reduced pressure of 200 mmHg.
• control In the "control" bottle containing the polymerization product, it is stopped with an excess of methanol relative to lithium.
• the inherent viscosity (initial" viscosity), which is measured at 25 ° C. at 0.1 g / dl in toluene, is 0.94 dl / g.
• the molecular weight Mn of this control determined by the SEC3D technique, is 92,000 g / mol, Np is 1.07.
• the viscosity jump defined as the ratio of said "final” viscosity to said "initial” viscosity, is here 1.62.
• the ML viscosity of the polymer thus coupled is 41.
• the resulting chain-functionalized SiOH-functional copolymer A was subjected to an antioxidant treatment by the addition of 0.35 parts per hundred parts of elastomers (phr) of 4,4'-methylene-bis-2,6- tert-butylphenol and 0.10 parts per hundred parts elastomers (phr) of N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine. This copolymer is recovered by drying in an oven at 60 ° C. under a stream of nitrogen.
• the mass ratio of 1,4-trans units is 34%, that of 1,4-cis units is 25% and that of 1,2 units is 41% (each of these three levels relates to butadiene units). .
• the mass content of styrene is 27%.
• the molecular weight Mn of this copolymer A determined by the conventional SEC technique, is 139,000 g / mol, the molecular weight Mw is 158,000 g / mol, the Ip is 1.14.
• the degree of CH 3 Si functions determined by 1 H NMR for copolymer A is 4.15 mmol / kg, which, taking into account the molecular weight Mn, corresponds to a T ratio of 0.38.
• NMR and SEC analyzes illustrate that the coupling reaction carried out in the presence of a polar chelating agent is particularly selective.
• This test is a control over the invention.
• a "control" bottle of 0.25 l maintained under nitrogen and in another identical bottle intended for the implementation of the invention 105 grams of cyclohexane (135 ml), butadiene and styrene are introduced, according to respective weight ratios 1/0, 104 / 0.045. 2,600 ppm of tetrahydrofuran is also introduced as a vinyl-link promoter. After neutralization of the impurities using n-BuLi, 123 ⁇ mol of n-butyl lithium is added. The polymerization is conducted in each of the two bottles at 40 ° C., and the converted monomer content is 78% after 100 min. This level is determined by weighing an extract dried at 110 ° C. under the reduced pressure of 200 mmHg.
• control In the "control" bottle containing the polymerization product, it is stopped with an excess of methanol relative to lithium.
• the inherent viscosity (initial" viscosity), which is measured at 25 ° C. at 0.1 g / dl in toluene, is 0.92 dl / g.
• the molecular weight Mn of this control determined by the SEC3D technique, is 98 000 g / mol, the Ip is 1.07.
• the viscosity jump defined as the ratio of said "final” viscosity to said "initial” viscosity, is here 2.01.
• the ML viscosity of the polymer thus coupled is 60.
• the resulting chain-functionalized SiOH-functional copolymer B was subjected to an antioxidant treatment by the addition of 0.35 parts per hundred parts of elastomers (phr) of 4,4'-methylene-bis-2,6- tert-butylphenol and 0.10 parts per hundred parts elastomers (phr) of N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine. This copolymer is recovered by drying in an oven at 60 ° C. under a stream of nitrogen.
• the mass ratio of BR 1,4-trans is 34%, that of BR 1,4-cis is 22% and that of BR 1,2 is 44% (each of these three rates refers to butadiene units) .
• the mass content of styrene is 26%.
• the molecular weight Mn of this copolymer B determined by the conventional SEC technique, is 170,000 g / mol, the molecular weight Mw is 209,000 g / mol, the Ip is 1.23.
• the overall CH 3 Si function rate determined by 1 H NMR for the copolymer B is 4.2 mmol / kg, which corresponds to a T ratio of 0.42.
• the copolymer B has a proportion of Si in the form of middle chain SiOH functions of 47%.
• NMR and SEC analyzes allow to conclude the existence of several functions in significant proportions characterizing the fact that the coupling reaction carried out in the presence of a non-chelating polar agent is not selective.
• This linear "control" SBR C functional hexamethylcydotrisiloxane is prepared by a copolymerization of styrene and butadiene.
• the molecular weight M n of this copolymer C is 133,000 g / mol.
• the ML viscosity of the copolymer is 39.
• this copolymer C is determined by NMR ⁇ 3 C, the mass ratio of BR 1, 4-trans is 34%, that of BR 1, 4-cis is 25% and that of BR 1, 2 is 41% (each of these three rates refers to butadiene units).
• the mass content of styrene is 26%.
• This non-functional "Control" SBR is prepared by copolymerization of styrene and butadiene.
• the linear "control" D copolymer thus obtained is subjected to an antioxidant treatment by the addition of 0.35 parts per hundred parts of 4,4'-methylene-bis-2,6-tert-butylphenol elastomers (phr). and 0.1 parts per hundred parts elastomers (phr) of N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine.
• This copolymer is recovered by drying in an oven at 60 ° C. under a stream of nitrogen.
• the ML viscosity of the copolymer is 39.
• the molecular weight Mn of this copolymer D is 143,000 g / mol.
• this copolymer D is determined by 13 C NMR: the mass ratio of BR 1, 4-trans is 33%, that of BR 1, 4-cis is 24% and that of BR 1, 2 is 43%. % (each of these three rates refers to butadiene units).
• the mass content of styrene is 26%.
• Copolymers E, F, G, H coupled and functional SiOH chain medium according to the invention in comparison with SBR copolymers I, J, K, L "controls" functionalized SiOH at the end of the chain and non-functional
• 32.5 l of cyclohexane, butadiene, styrene and tetrahydrofurfuryl ethyl ether are continuously fed into a 32.5-l reactor with a mass flow rate of 100/1 1 / 3.2 / 0.045, respectively.
• 160 micromoles of n-butyllithium (n-BuLi) are introduced at the line inlet for 100 g of monomers in order to neutralize the protic impurities introduced by the various constituents present in the line inlet.
• 1,160 ⁇ mol of n-BuLi is introduced per 100 g of monomers.
• the different flow rates are adjusted such that the average residence time in the reactor is 40 minutes.
• the temperature is maintained at 70 ° C.
• the conversion rate which is measured on a sample taken at the reactor outlet, is 96% and the inherent viscosity, which is measured at 25 0 C in
• 0.1 g / dl in toluene is 1.28 dl / g.
• the molecular weight Mn measured by SEC3D is 83,000 g / mol.
• the copolymer thus treated is separated from its solution by a stripping operation with steam, and then dried on a roll tool at 100 ° C. for 20 min to obtain the coupled and functionalized SiOH copolymer in the middle of the chain. according to the invention.
• the inherent viscosity of this copolymer E is 1.69 dl / g, the viscosity jump is 1.32 and its viscosity ML is 55.
• the molecular weight of the copolymer, determined by the conventional SEC technique, is 137,000. g / mol, the molecular weight Mw is 237 000 mol / g, the Ip is 1.73.
• microstructure of this copolymer E is determined by 13 C NMR.
• the SBR block of this copolymer E contains 25% of styrene (by weight) and, for its butadiene part, 59% of vinyl units, 21% of 1,4-cis units and 20% of 1,4-trans units.
• NMR and SEC analyzes illustrate that the coupling reaction carried out in the presence of a polar chelating agent is particularly selective.
• the different flow rates are adjusted so that the average residence time in the reactor is 40 minutes.
• the temperature is maintained at 70 ° C.
• the conversion rate which is measured on a sample taken at the reactor outlet, is 95% and the inherent viscosity, which is measured at 25 0 C in
• 0.1 g / dl in toluene is 1.61 dl / g.
• the molecular weight Mn measured by the SEC3D technique is 1 18 000 g / mol.
• the copolymer thus treated is separated from its solution by a stripping operation with steam, and then dried on a roll tool at 100 ° C. for 20 min to obtain the coupled and functionalized SiOH copolymer in the middle of the chain. according to the invention.
• the inherent viscosity of this copolymer F is 2.18 dl / g, the viscosity jump is 1.35 and its viscosity ML is 81.
• the molecular weight of the copolymer, determined by the conventional SEC technique, is 185,000 g / mol, the molecular weight Mw is 323,000 mol / g, the Ip is 1.75.
• the SBR block of this copolymer F contains 25% of styrene (by weight) and, for its butadiene part, 58% of vinyl units, 21% of 1,4 cis units and 21% of 1,4 trans units.
• 32.5 l of cyclohexane, butadiene, styrene and tetrahydrofurfuryl ethyl ether are continuously fed into a 32.5-l reactor at mass flow rates of 100/1 1 / 3.2 / 0.048, respectively. .
• 160 micromoles of n-butyllithium (n-BuLi) per 100 g of monomers are introduced at the line inlet in order to neutralize the protic impurities introduced by the various constituents present in the line inlet.
• 1460 ⁇ mol of n-BuLi is introduced per 100 g of monomers.
• the different flow rates are adjusted so that the average residence time in the reactor is 40 minutes.
• the temperature is maintained at 70 ° C.
• the conversion rate which is measured on a sample taken at the reactor outlet, is 97% and the inherent viscosity, which is measured at 25 0 C in
• 0.1 g / dl in toluene is 1.06 dl / g.
• the molecular weight Mn determined by the SEC3D technique is 66,000 g / mol.
• the copolymer thus treated is separated from its solution by a stripping operation with steam, and then dried on a roll tool at 100 ° C. for 20 min to obtain the coupled and functionalized SiOH copolymer in the middle of the chain. according to the invention.
• the inherent viscosity of this copolymer G is 1.40 dl / g, the viscosity jump is 1.32 and its viscosity ML is 37.
• the molecular weight of the copolymer, determined by the conventional SEC technique, is 1 14 000 g / mol, the molecular weight Mw is 190,000 mol / g, the Ip is 1.67.
• microstructure of this copolymer G is determined by 13 C NMR.
• the SBR block of this copolymer G contains 25.1% of styrene (by weight) and, for its butadiene part, 58% of vinyl units, 22% of 1,4 cis units and
• the ratio of CH 3 Si functions determined by 1 H NMR for the copolymer G is 6.16 mmol / kg, which corresponds to a T ratio of 0.40.
• 32.5 l equipped with a turbine-type stirrer are continuously fed with cyclohexane, butadiene, styrene and tetrahydrofurfuryl ethyl ether, at respective mass flow rates of 100.
• n-butyllithium (n-BuLi) per 100 g of monomers are introduced at the line inlet in order to neutralize the protic impurities introduced by the various constituents present in the line inlet.
• n-BuLi n-butyllithium
• the different flow rates are adjusted so that the average residence time in the reactor is 40 minutes.
• the temperature is maintained at 80 ° C.
• the conversion rate which is measured on a sample taken at the outlet of the reactor, is 89%, and the inherent viscosity, which is measured at 25 ° C. at 0.1 g / dL in toluene, is 1.27 dl / g.
• the molecular weight Mn determined by the SEC3D technique is 76,000 g / mol.
• the copolymer thus treated is separated from its solution by a stripping operation with steam, and then dried on a roll tool at 100 ° C. for 20 min to obtain the coupled and functionalized SiOH copolymer in the middle of the chain. according to the invention.
• the inherent viscosity of this copolymer H is 1.68 dl / g, the viscosity jump is 1.32 and its viscosity ML is 53.
• the molecular weight of the copolymer, determined by the conventional SEC technique, is 130,000. g / mol, the molecular weight Mw is 208,000 mol / g, the Ip is 1.60.
• the SBR block of this copolymer H contains 28% of styrene (by weight) and, for its butadiene part, 24% of vinyl units, 30% of 1,4 cis units and 46% of 1,4-trans units.
• the ratio of CH 3 Si functions determined by 1 H NMR for the copolymer H is 7.63 mmol / kg, which corresponds to a T ratio of 0.58.
• the different flow rates are adjusted so that the average residence time in the reactor is 40 minutes.
• the temperature is maintained at 70 ° C.
• the conversion rate which is measured on a sample taken at the outlet of the reactor, is 98%.
• the copolymer thus treated is separated from its solution by a stripping operation with steam, and then dried on a roll tool at 100 ° C. for 20 min to obtain the functionalized SiOH functional copolymer at the end of the chain.
• the ML viscosity of this copolymer I is 53.
• the molecular weight of the copolymer, determined by conventional SEC, is 123,000 g / mol.
• the microstructure of this copolymer I is determined by 13 C NMR.
• the SBR block of this copolymer I contains 25% of styrene (by weight) and, for its butadiene part, 58% of vinyl units, 21% of 1,4 cis units and 21% of 1,4 trans units.
• the 1 H- 29 Si 2D NMR analysis makes it possible to conclude that an end-of-chain function SBR (CH 3 ) 2 SiOH exists.
• the degree of function (CH 3 ) 2 Si determined by 1 H NMR for the copolymer I is 5.85 mmol / kg.
• the ML viscosity of copolymer J is 53.
• the molecular weight of the copolymer, determined by conventional SEC, is 123,000 g / mol.
• microstructure of this copolymer J is determined by 13 C NMR.
• the SBR block of this copolymer J contains 25% of styrene (by weight) and, for its butadiene part, 58% of vinyl units, 21% of 1,4 cis units and 21% of 1,4 trans units.
• 32.5 l of cyclohexane, butadiene, styrene and tetrahydrofurfuryl ethyl ether are continuously fed into a 32.5-l reactor, with respective mass flow rates of 100 / 9.8 / 4.4. 0.0043.
• 200 micromoles of n-butyllithium (n-BuLi) per 100 g of monomers are introduced at the line inlet in order to neutralize the protic impurities introduced by the various constituents present in the line inlet.
• 610 ⁇ mol of n-BuLi is introduced per 100 g of monomers.
• the different flow rates are adjusted so that the average residence time in the reactor is 40 minutes.
• the temperature is maintained at 80 ° C.
• the conversion rate which is measured on a sample taken at the outlet of the reactor, is 93%.
• the copolymer thus treated is separated from its solution by a stripping operation with steam, and then dried on a roll tool at 100 ° C. for 20 min to obtain the functionalized SiOH functional copolymer at the end of the chain.
• the ML viscosity of copolymer K is 54.
• the molecular weight of the copolymer, determined by conventional SEC, is 19,000 g / mol.
• the microstructure of this copolymer K is determined by 13 C NMR.
• the SBR block of this copolymer K contains 27% of styrene (by weight) and, for its butadiene part, 24% of vinyl units, 30% of 1,4 units. cis and 46% 1,4 trans units.
• the viscosity ML is 54.
• microstructure of this copolymer L is determined by 13 C NMR.
• the SBR block of this copolymer L contains 27% of styrene (by weight) and, for its butadiene part, 24% of vinyl units, 30% of 1,4-cis units and 46% of 1,4-trans units.
• compositions comprising either an elastomer having a silanol function in the middle of the chain according to the invention, or an elastomer not in accordance with the invention
• compositions A, B, C or D has the following formulation (expressed in phr: parts per hundred parts of elastomer):
• Aromatic oil (“ENERFLEX 65”) (5) 39.5
• compositions are carried out, in a first thermomechanical working time, by two steps separated by a cooling phase, then, in a second finishing time, by mechanical work.
• the first thermomechanical working step is carried out for 4 to 5 minutes, until a maximum temperature of about 160 ° C. falls.
• the elastomeric block is then recovered and cooled.
• thermomechanical working step is carried out in the same mixer for a period of 3 to 4 minutes, with addition of zinc monoxide and antioxidant, up to a maximum temperature of 160 ° C. about.
• thermomechanical work is thus achieved, it being specified that the average speed of the pallets during this first time is 45 rpm.
• the mixture thus obtained is recovered, cooled and then, in an external mixer (homo-finisher), the sulfur and sulfenamide are added at 30 ° C., mixing again for a period of 3 to 4 minutes (second time). aforementioned mechanical work).
• the compositions thus obtained are then calendered, either in the form of plates (with a thickness ranging from 2 to 3 mm) or thin rubber sheets, for the measurement of their physical or mechanical properties, or in the form of directly usable profiles, after cutting and / or assembly to the desired dimensions, for example as semi-finished products for tires, in particular for treads.
• the crosslinking is carried out at 150 ° C. for 40 min.
• composition A B C D Composition A B C D
• composition A according to the invention has a Mooney value "mixture” which is comparable to that of the composition D based on a non-functional elastomer.
• the composition A according to the invention has a Mooney value "mixture” which is significantly lower than that of the composition C based on an elastomer which comprises a SiOH function at the end of the chain.
• the functional elastomer according to the invention makes it possible to improve the implementation with respect to the functional SiOH elastomer at the end of the chain.
• the MA300 / MA100 ratio of the composition A according to the invention is equivalent to that of the composition C based on an elastomer which comprises an SiOH function at the end of the chain.
• the composition A according to the invention has an M A300 / MA 100 ratio which is significantly higher than that of the composition D based on a non-functional elastomer.
• the functional elastomer according to the invention makes it possible to improve the reinforcement with respect to the non-functional elastomer.
• composition B has an MA300 / MA100 ratio which is lower than that of composition A according to the invention. This result clearly demonstrates that the reinforcement is markedly improved only for the composition according to the invention.
• the hysteretic properties (at low and high deformations) of the composition A according to the invention are close to those of the composition C based on an elastomer which comprises an SiOH function at the end of the chain.
• the composition A according to the invention has hysteretic properties (at low and high deformations) which are significantly improved compared with those of the composition D based on a non-functional elastomer.
• the functional elastomer according to the invention makes it possible to improve the hysteretic properties (at low and high deformations) relative to the non-functional elastomer.
• the functional elastomer according to the invention gives composition A a compromise of properties in the uncrosslinked state.
• composition B has hysteretic properties (at low and high deformations) which are degraded compared with those of composition A according to the invention. This result clearly demonstrates that the hysteretic properties (at low and high deformations) are better only for the composition according to the invention.
• composition A according to the invention based on an elastomer which comprises a SiOH function in the middle of the chain, the proportion of Si found as a mid-chain SiOH function is 100%, has cross-linked rubber properties which are improved over those of the non-functional elastomeric composition D due to reduced hysteresis. and with respect to the elastomeric composition C comprising an end-chain SiOH function due to improved processability.
• Composition A according to the invention based on an elastomer which comprises a SiOH function in the middle of the chain, the proportion of Si in the form of SiOH function in the middle of the chain is 100%, has rubber properties in the crosslinked state which are improved over those of composition B, the proportion of Si in the form of middle chain SiOH function is 47%, due to reduced hysteresis at low and high deformations and because of improved reinforcement.
• compositions comprising either an elastomer having a silanol function in the middle of the chain according to the invention, or an elastomer not in accordance with the invention
• compositions E, I and J has the following formulation (expressed in phr: parts per hundred parts of elastomer):
• Antioxidant (3) 1.9 Anti-Ozone Wax "C32ST” (6) 1.5
• compositions are carried out, in a first thermomechanical working time, by two steps separated by a cooling phase, then, in a second finishing time, by mechanical work.
• the first thermomechanical working step is carried out for 4 to 5 minutes, until a maximum temperature of about 160 ° C. falls.
• the elastomeric block is then recovered and cooled.
• thermomechanical working step is carried out in the same mixer for a period of 3 to 4 minutes, with the addition of zinc monoxide and antioxidant, up to a maximum temperature of 160 ° C. about.
• thermomechanical work is thus achieved, it being specified that the average speed of the pallets during this first time is 45 rpm.
• the mixture thus obtained is recovered, cooled and then, in an external mixer (homo-finisher), the sulfur and sulfenamide are added at 30 ° C., mixing again for a period of 3 to 4 minutes (second aforementioned mechanical working time).
• compositions thus obtained are then calendered, either in the form of plates (with a thickness ranging from 2 to 3 mm) or thin rubber sheets, for the measurement of their physical or mechanical properties, or in the form of directly usable profiles, after cutting and / or assembly to the desired dimensions, for example as semi-finished products for tires, in particular for treads.
• the crosslinking is carried out at 150 ° C. for 40 min.
• the composition E according to the invention has a Mooney value "mixture” which is comparable to that of the composition J based on a non-functional elastomer.
• the composition E according to the invention has a Mooney value "mixture” which is significantly lower than that of the composition I based on an elastomer which comprises an SiOH function at the end of the chain.
• the functional elastomer according to the invention makes it possible to improve the implementation with respect to the functional SiOH elastomer at the end of the chain.
• the MA300 / MA100 ratio of the composition E according to the invention is close to that of the composition I based on an elastomer which comprises an SiOH function at the end of the chain.
• composition E according to the invention has a MA300 / MA100 ratio which is significantly higher than that of the composition J based on a non-functional elastomer.
• the functional elastomer according to the invention makes it possible to improve the reinforcement with respect to the non-functional elastomer.
• the hysteretic properties (at low and high deformations) of the composition E according to the invention are close to those of the composition I based on an elastomer which comprises an SiOH function at the end of the chain.
• the composition E according to the invention has hysteretic properties (low and high deformations) which are improved compared to those of the composition J based on a nonfunctional elastomer.
• the functional elastomer according to the invention makes it possible to improve the hysteretic properties (at low and high deformations) relative to the non-functional elastomer.
• composition E according to the invention based on elastomer which comprises a SiOH function in the middle of the chain, and the proportion of Si in the form of SiOH function in the middle of the chain is 94% has cross-linked rubber properties which are improved over those of the non-functional elastomeric composition J due to reduced hysteresis on the one hand and relative to the composition I based on elastomer comprising an SiOH function at the end of the chain because of improved processability on the other hand.
• compositions comprising either an elastomer having a silanol function in the middle of the chain according to the invention, or an elastomer not in accordance with the invention
• compositions H, K, and L has the following formulation (expressed in phr: parts per hundred parts of elastomer):
• the first thermomechanical working step is carried out for 4 to 5 minutes, until a maximum temperature of about 160 ° C. falls.
• the elastomeric block is then recovered and cooled.
• thermomechanical work is thus achieved, it being specified that the average speed of the pallets during this first time is 45 rpm.
• compositions thus obtained are then calendered, either in the form of plates (with a thickness ranging from 2 to 3 mm) or thin rubber sheets, for the measurement of their physical or mechanical properties, or in the form of directly usable profiles, after cutting and / or assembly to the desired dimensions, for example as semi-finished products for tires, in particular for treads.
• the crosslinking is carried out at 150 ° C. for 40 min.
• the composition H according to the invention has a Mooney value "mixture” which is comparable to that of the composition L based on a non-functional elastomer.
• the composition H according to the invention has a Mooney value "mixture” which is significantly lower than that of the composition K based on an elastomer which comprises a SiOH function at the end of the chain.
• the functional elastomer according to the invention improves the implementation compared to the SiOH functional elastomer chain end.
• the ratio M A300 / MA 100 of the composition H according to the invention is equivalent to that of the composition K based on an elastomer which comprises a SiOH function at the end of the chain. .
• composition H according to the invention has a MA300 / MA100 ratio which is significantly higher than that of the composition L based on a non-functional elastomer.
• the functional elastomer according to the invention makes it possible to improve the reinforcement with respect to the non-functional elastomer.
• the hysteretic properties (at low and high deformations) of the composition H according to the invention are close to those of the composition K based on an elastomer which comprises an SiOH function at the end of the chain.
• the composition H according to the invention has hysteretic properties (low and high deformations) which are significantly improved over those of the composition L based on a nonfunctional elastomer.
• the functional elastomer according to the invention makes it possible to improve the hysteretic properties (at low and high deformations) relative to the non-functional elastomer.
• the composition H according to the invention based on elastomer which comprises a SiOH function in the middle of the chain, and the proportion of Si in the form of SiOH function in the middle of the chain is 92% , has rubber properties which are improved in the crosslinked state compared to those of the non-functional elastomeric composition L due to a reduced hysteresis on the one hand and in the uncrosslinked state with respect to the elastomer composition K comprising an end-chain SiOH function because of improved processability on the other hand.
• the macromolecules are physically separated according to their respective sizes in the inflated state, in columns filled with a porous stationary phase.
• the polymer sample is solubilized at a concentration of about 1 g / l in tetrahydrofuran. Then the solution is filtered on a 0.45 ⁇ m porosity filter before injection.
• the injected volume of the polymer sample solution is 100 ⁇ l.
• the detector is a differential refractometer "WATERS” whose model is “2410”.
• Chromatographic data exploitation software whose trade name is WATERS EMPOWER, is also used.
• the calculated average molar masses relate to a calibration curve produced for SBRs of microstructure as follows: 25% by weight of styrene type units, 23% by mass of type 1-2 units and 50% by mass of type 1-4 trans units.
• SEC size exclusion chromatography
• This technique makes it possible to separate the macromolecules in solution according to their size through columns filled with a porous gel.
• the macromolecules are separated according to their hydrodynamic volume, the larger ones being eluted first.
• the SEC Associated with 3 detectors (3D), a refractometer, a viscometer and a 90 ° light scattering detector, the SEC allows to apprehend the distribution absolute molar masses of a polymer.
• the different average absolute molar masses by number (Mn), by weight (Mw) can also be calculated.
• the macromolecules are physically separated according to their respective sizes in the inflated state, in columns filled with a porous stationary phase.
• the polymer sample is solubilized at a concentration of about 1 g / l in tetrahydrofuran. Then the solution is filtered on a 0.45 ⁇ m porosity filter before injection.
• the apparatus used is a "WATERS alliance" chromatograph.
• the elution solvent is tetrahydrofuran, the flow rate is 0.5 ml / min and the temperature of the system is 35 ° C.
• a set of four columns POLYMER LABORATORIES is used in series, of commercial designations: two "MIXED A LS" and two "MIXED B LS”.
• the injected volume of the solution of the polymer sample is 100 ⁇ l.
• the detection system used is the "TDA 302 of VISCOTEK", it is composed of a differential refractometer, a differential viscometer and a 90 ° light scattering detector. For these 3 detectors, the wavelength is 670nm.
• the value of the refractive index increment dn / dC of the polymer solution previously defined value in tetrahydrofuran at 35 ° C and 670nm.
• the data exploitation software is the "OMNISEC system of VISCOTEK".
• the 1 H- 29 Si 2D NMR spectrum makes it possible to verify the nature of the function by virtue of the chemical shift values of the silicon nuclei and the protons in the neighborhood 2 J (via 2 links). It uses a coupling constant value 2 J 1H.29Si of 8 Hz.
• the chemical shift of the silicon of the product CH 3 Si (SBR) 2 OH in the middle of the chain is about 8 ppm, that of the form SBR (CH 3 J 2 SiOH at the end of the chain around 1-12 ppm.
• the samples are solubilized in carbon disulfide (CS 2 ).
• 100 ⁇ L of deuterated cyclohexane (C 6 D 12 ) are added for the lock signal.
• the NMR analyzes are carried out on a BRUKER 500 MHz spectrometer equipped with a BBI 5 mm broadband probe.
• the sequence uses a 30 ° pulse and a repetition time of 2 seconds.
• Ref 1 Beebe, DH Polymer 1978, 19, 231-33.
• Ref 2 Bradbury, JH; They, JA; Perera, MCS Journal of PoIy Sea Science 1988, 26, 615-26.
• Ref 3 durbetaki, AJ; miles, CM analytical chemistry 1965, 37, 1231-35.
• Ref 4 Gronski, W .; Murayama, N .; Cantow, H.-J. Polymer 1976, April, 358-60.
• Ref 5 Kobayashi, E .; Furakawa, J .; Ochiai, M .; Tsujimoto, T. European Polymer J. 1983, 10, 871-75.
• the spectral width is 200 ppm, the number of scans is 8192.
• the spectra are calibrated on the central peak of the CDCI triplet 3 to
• the inherent viscosity is determined by measuring the flow time t of the polymer solution and the flow time t 0 of toluene in a capillary tube.
• the Shore A hardness of the compositions after curing is assessed according to ASTM D 2240-86.
• ⁇ G * max and tan ( ⁇ ) max are measured on a viscoanalyzer (Metravib VA4000) according to ASTM D 5992-96.
• the response of a sample of vulcanized composition (cylindrical specimen 4 mm in thickness and 400 mm 2 in section) is recorded, subjected to sinusoidal stress in alternating simple shear, at the frequency of 10 Hz, under normal conditions. temperature (23 0 C or 40 0 C) according to the standard
• the hysteresis properties can be evaluated by measuring the energy loss by rebound energy imposed samples measured at 6 th shock, under normal conditions of temperature (23 0 C) or at higher temperature (60 0 C) and expressed in% according to the following relationship:
• PH (%) 100 [(WO-W1) / WO] with WO: energy supplied; W1: restored energy.

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