Classifications

• • 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
  • C08K5/54—Silicon-containing compounds
  • C08K5/548—Silicon-containing compounds containing sulfur
• • 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
• • 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
  • B60C1/0008—Compositions of the inner liner
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
  • B60C1/0025—Compositions of the sidewalls
• • 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
  • B60C5/00—Inflatable pneumatic tyres or inner tubes
  • B60C5/02—Inflatable pneumatic tyres or inner tubes having separate inflatable inserts, e.g. with inner tubes; Means for lubricating, venting, preventing relative movement between tyre and inner tube
• • 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
  • B60C5/00—Inflatable pneumatic tyres or inner tubes
  • B60C5/12—Inflatable pneumatic tyres or inner tubes without separate inflatable inserts, e.g. tubeless tyres with transverse section open to the rim
  • B60C5/16—Sealing means between beads and rims, e.g. bands
• • 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
  • C08F36/02—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
  • C08F36/04—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
• • 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
  • C08K5/54—Silicon-containing compounds
  • C08K5/549—Silicon-containing compounds containing silicon in a ring
• • 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
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
  • B60C2015/0614—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead characterised by features of the chafer or clinch portion, i.e. the part of the bead contacting the rim

Definitions

• the present invention relates to rubber compositions which can be used in particular for the manufacture of tires or semi-finished products for tires, as well as to crosslinking agents which can be used for crosslinking elastomeric networks in such compositions.
• the principle of vulcanization lies in the creation of sulfur bridges between two macromolecules by reaction on the double bonds of these diene elastomers.
• One of the remarkable characteristics of vulcanization is the simplicity with which this reaction can be controlled by adding compounds having an accelerating or retarding effect.
• By playing on the respective sulfur and accelerator levels it is in particular possible to control the vulcanization yield, to obtain sulfur bridges of different configurations which lead, for a given rubber composition, to possible adjustments of the properties. , both raw and cooked.
• sulfur vulcanization has certain known drawbacks, including the problem of blooming in the raw state, due to migration of sulfur to the surface of the rubber articles considered, and above all a limited resistance of the vulcanizates in the baked state, due to thermal aging of the latter ("thermal aging").
• the vulcanizates of diene elastomers crosslinked from sulfur exhibit significant sensitivity to temperature when the latter reaches a value close to the initial curing or vulcanization temperature.
• This phenomenon known as reversion, is accompanied by a degradation of the mechanical properties of the vulcanized material.
• a first subject of the invention relates to a rubber composition, usable for the manufacture of tires, based on at least one diene elastomer, a reinforcing filler and a siloxane polysulfide corresponding to the general formula (I):
• the number x, whole or fractional, is equal to or greater than 2;
• the radicals Z, which are identical or different, are divalent linking groups preferably comprising from 1 to 18 carbon atoms;
• the radicals R, which are identical or different, are hydrocarbon groups preferably comprising from 1 to 18 carbon atoms.
• the rubber compositions according to the invention having improved resistance to reversion, based on a diene elastomer, a reinforcing filler and a crosslinking system, are capable of being prepared by a process which constitutes a Another object of the invention, said method comprising the following steps: incorporating into a diene elastomer, during a first step called “non-productive", at least one reinforcing filler, by thermomechanically kneading the whole, in one or more times, until reaching a maximum temperature between 110 ° C and 190 ° C; • cool the assembly to a temperature below 100 ° C; then incorporating, during a second so-called “productive” step, the crosslinking system; kneading everything up to a maximum temperature below 110 ° C., and being characterized in that said crosslinking system comprises a polysulfide siloxane corresponding to the general formula (I) above.
• the invention also relates to the use of a composition according to the invention for the manufacture of finished articles or semi-finished products comprising a rubber composition according to the invention, these articles or products being intended for any ground connection system for motor vehicles, such as tires, internal safety supports for tires, wheels, rubber springs, elastomeric joints, other suspension and anti-vibration elements.
• the invention particularly relates to the use of a composition according to the invention for the manufacture of tires or semi-finished rubber products intended for these tires, these semi-finished articles being chosen in particular from the group consisting by the treads, the sub-layers intended for example to be placed under these treads, the crown reinforcement plies, the sides, the plies
• a subject of the invention is also these finished articles and semi-finished products themselves, in particular tires and semi-finished products for tires, when they comprise an elastomeric composition in accordance with the invention.
• the tires in accordance with the invention may in particular be intended for passenger vehicles as well as for industrial vehicles chosen from vans, "Heavy goods vehicles” - ie, metro, bus, road transport equipment (trucks, tractors, trailers), off-road vehicles - the road -, agricultural or civil engineering machinery, planes, other transport or handling vehicles.
• the rubber compositions are characterized, before and after curing, as indicated below.
• the Mooney plasticity measurement is made according to the following principle: the composition in the raw state (i.e., before baking) is molded in a cylindrical enclosure heated to 100 ° C. After one minute of preheating, the rotor turns within the test tube at 2 revolutions / minute and the torque useful for maintaining this movement is measured after 4 minutes of rotation.
• the measurements are carried out at 130 ° C, in accordance with French standard NF T 43-005 (1991).
• the evolution of the consistometric index as a function of time makes it possible to determine the toasting time of the rubber compositions, assessed in accordance with the aforementioned standard by parameter T5 (case of a large rotor), expressed in minutes, and defined as being the time necessary to obtain an increase in the consistometric index (expressed in MU) of 5 units above the minimum value measured for this index.
• P10-1441 / JR rheometric as a function of time describes the evolution of the stiffening of the composition as a result of the vulcanization reaction (see attached FIG. 4).
• the measurements are processed according to DIN 53529 - part 2 (March 1983): the minimum and maximum torques, measured in dN.m (deciNewton.meter), are respectively named C mm and C max ; t, is the induction time, that is to say the time necessary for the start of the vulcanization reaction.
• t is the induction time, that is to say the time necessary for the start of the vulcanization reaction.
• ⁇ Couple in dN.m
• the mechanical or dynamic properties indicated below are those measured at the "optimum cooking", that is to say, in known manner, those obtained, for a temperature of determined cooking, after the minimum cooking time to reach the maximum rheometric torque C max .
• the dynamic properties ⁇ G * and tan max ( ⁇ ) are measured on a viscoanalyzer (Metravib VA4000), according to standard ASTM D 5992-96.
• the response of a sample of vulcanized composition (4 mm thick cylindrical test piece and 400 mm 2 section) is recorded, subjected to a sinusoidal stress in alternating single shear, at the frequency of 10 Hz, under normal conditions of temperature (23 ° C) according to standard ASTM D 1349-99.
• a deformation amplitude sweep is carried out from 0.1 to 50% (outward cycle), then from 50% to 1% (return cycle).
• the exploited results are the complex dynamic shear modulus (G *) and the loss factor tan ( ⁇ ).
• G * complex dynamic shear modulus
• ⁇ loss factor
• the reversion can be analyzed according to different methods, the aim being to determine, in an indirect way, the evolution of the density of the sulfur bridges, between a cooking at the optimum (C max ) and a prolonged cooking.
• the first approach consists in measuring the evolution of the rheometric torque: the parameters ⁇ R 60 and ⁇ R 120 represent the evolution in% of the torque between C max and the torque measured after
• P10-1441 / JR 60 or 120 min of cooking respectively, at a determined cooking temperature (for example 150 ° C or 165 ° C).
• the second approach consists in measuring the evolution of the MAI 00 or MA300 modules: the parameters ⁇ MA100 and ⁇ MA300 correspond to the evolution in% of the respective modules between the optimum cooking (C max ) and after a prolonged cooking of 2 hours, at a specific cooking temperature (for example 150 ° C or 165 ° C).
• the rubber compositions according to the invention are based on at least one diene elastomer, a reinforcing filler and a siloxane polysulphide corresponding to the general formula (I) mentioned above.
• composition based on
• a composition comprising the mixture and / or the in situ reaction product of the various constituents used, some of these base constituents being capable of, or intended to react between them, at least in part, during the various stages of manufacturing the composition, in particular during its crosslinking.
• iene elastomer or rubber in known manner an elastomer derived at least in part (i.e. a homopolymer or a copolymer) from diene monomers (monomers carrying two carbon-carbon double bonds, conjugated or not).
• diene elastomer a diene elastomer derived at least in part from conjugated diene monomers, having a rate of units or units of diene origin (conjugated dienes) which is greater than 15% (% in moles).
• diene elastomers such as butyl rubbers or copolymers of dienes and of alpha-olefins of the EPDM type do not enter into the preceding definition and can be qualified in particular as "essentially saturated diene elastomers". "(rate of motifs of diene origin low or very low, always less than 15%).
• the expression “highly unsaturated” diene elastomer is understood in particular to mean a diene elastomer having a content of units of diene origin (conjugated dienes) which is greater than 50%.
• P10-1441 / JR (a) - any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms;
• 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di (C1-C5 alkyl) -1,3-butadienes such as, for example, are suitable.
• vinyl-aromatic compounds suitable for example, styrene, ortho-, meta-, para-methylstyrene, the commercial "vinyl-toluene" mixture, para-tertiobutylstyrene, methoxystyrenes, chlorostyrenes, vinyl mesitylene, divinylbenzene , vinylnaphthalene.
• the copolymers can contain between 99% and 20% by weight of diene units and from 1% to 80% by weight of vinyl aromatic units.
• the elastomers can have any microstructure which is a function of the polymerization conditions used, in particular the presence or absence of a modifying and / or randomizing agent and the quantities of modifying and / or randomizing agent used.
• the elastomers can for example be block, statistical, sequence, microsequenced and be prepared in dispersion or in solution; they can be coupled and / or stars or functionalized with a coupling and / or star-forming or functionalizing agent.
• polybutadienes are suitable and in particular those having a content of -1,2 units between 4% and 80% or those having a cis-1,4 content greater than 80%, polyisoprenes, butadiene copolymers- styrene and in particular those having a styrene content of between 5% and 50% by weight and more particularly between 20% and 40%, a content of -1,2 bonds in the butadiene part of between 4% and 65%, a content of trans-1,4 bonds of between 20% and 80%, butadiene-isoprene copolymers and in particular those having an isoprene content of between 5% and 90% by weight
• Tg glass transition temperature
• butadiene-styrene-isoprene copolymers are particularly suitable those having a styrene content of between 5% and 50% by weight and more particularly between 10% and 40%, an isoprene content of between 15% and 60% by weight and more particularly between 20% and 50%, a butadiene content of between 5% and 50% by weight and more particularly between 20% and 40%, a content of -1.2 units of the butadiene part of between 4% and 85%, a content in trans units -1.4 of the butadiene part between 6% and 80%, a content in units -1.2 plus -3.4 of the isoprene part between 5% and 70 % and a content of trans units -1.4 of the isoprenic part of between 10% and 50%, and more generally any butadiene-styrene-isoprene copolymer having a Tg of between -20 ° C. and -70 ° C.
• the diene elastomer of the composition according to the invention is chosen from the group of highly unsaturated diene elastomers constituted by polybutadienes (BR), natural rubber (NR), polyisoprenes synthesis (IR), butadiene copolymers (in particular butadiene-styrene (SBR), butadiene-isoprene (BIR), butadiene-acrylonitrile (NBR)), isoprene copolymers (in particular isoprene-styrene (SIR) or butadiene -styrene-isoprene (SBIR)), and mixtures of these elastomers.
• BR polybutadienes
• NR natural rubber
• IR polyisoprenes synthesis
• IR butadiene copolymers
• SBR butadiene-styrene
• BIR butadiene-isoprene
• NBR butadiene-acrylonitrile
• composition according to the invention can, for example, be used as a tread for a tire, whether it is a new or used tire (in the case of retreading).
• the diene elastomer is preferably an SBR or a blend (mixture) of SBR / BR, SBR / NR (or SBR / IR), or BR / NR (or BR / IR).
• an SBR elastomer in particular an SBR is used having a styrene content of between 20% and 30% by weight, a vinyl bond content of the butadiene part of between 15% and 65%, a bond content trans-1,4 between 15% and 75% and a Tg between -20 ° C and -55 ° C
• this SBR copolymer preferably prepared in solution (SSBR), being optionally used in admixture with a polybutadiene (BR ) preferably having more than 90% of cis-1,4 bonds.
• the diene elastomer is preferably, at least for the most part, an isoprene elastomer.
• isoprene elastomer means, in a known manner, a homopolymer or a copolymer of isoprene, in other words a diene elastomer chosen from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), the various isoprene copolymers and mixtures of these elastomers.
• isoprene copolymers mention will be made in particular of isobutene-isoprene (butyl rubber - IIR), isoprene-styrene (SIR), isoprene-butadiene (BIR) and isoprene copolymers.
• the isoprene elastomer is preferably natural rubber or a synthetic polyisoprene of the cis-1,4 type.
• polyisoprenes are preferably used having a rate (mol%) of cis-1,4 bonds greater than 90%, more preferably still greater than 98%.
• the diene elastomer can also consist, in part, of another highly unsaturated elastomer such as, for example, an SBR elastomer.
• the composition according to the invention may contain at least one essentially saturated diene elastomer, in particular at least one EPDM copolymer, that this copolymer is for example used or not in admixture with one or more of the highly unsaturated diene elastomers mentioned above.
• compositions of the invention may contain a single diene elastomer or a mixture of several diene elastomers, the diene elastomer or elastomers being able to be used in combination with any type of synthetic elastomer other than diene, or even with polymers other than elastomers, for example thermoplastic polymers.
• reinforcing filler known for its capacity to reinforce a rubber composition which can be used for the manufacture of tires, for example an organic filler such as carbon black or an inorganic reinforcing filler such as silica which will be used, can be used. then associated a coupling agent.
• carbon blacks all carbon blacks are suitable, in particular blacks of the HAF ("High Abrasion Furnace”), ISAF ("Intermediate Super Abrasion Furnace”), SAF ("Super Abrasion Furnace”) type, conventionally used in tires ( tire grade black tires), for example in the treads of these tires.
• HAF High Abrasion Furnace
• ISAF Intermediate Super Abrasion Furnace
• SAF Super Abrasion Furnace
• the reinforcing carbon blacks of the 100, 200 or 300 series such as, for example, the blacks NI 15, N134, N234, N330, N339, N347, N375.
• mineral fillers of the siliceous type in particular silica (SiO 2), or of the aluminous type, in particular of alumina (Al 2 O 3) or aluminum (oxide) hydroxides, are suitable.
• 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 as well as a CTAB specific surface, both less than 450 mVg, preferably from 30 to 400 m 2 / g .
• Highly dispersible precipitated silicas are preferred, in particular when the invention is used for the manufacture of tires having low rolling resistance; as examples of HD silicas, mention may be made of Ultrasil 7000 and Ultrasil 7005 of the company
• any known coupling or binding agent is used, in particular organosilanes or polyorganosiloxanes which are at least bifunctional.
• Use will be made in particular of polysulphurized silanes, said to be “symmetrical” or “asymmetrical” according to their particular structure, as described for example in patents or patent applications FR 2 149 339, FR 2 206 330, US 3 842 111, US 3 873 489, US 3,978 103, US 3,997,581, US 4,002,594, US 4,072,701, US 4,129,585, US 5,580,919, US 5,583,245, US 5,650,457, US 5,663,358, US 5,663 395, US 5 663 396, US 5 674 932, US 5 675 014, US 5 684 171, US 5 684 172, US 5 696 197, US 5 708 053, US 5 892 085, EP 1 043 3
• the rate of total reinforcing filler is between 20 and 200 phr, more preferably between 30 and 150 phr (parts by weight per hundred parts of elastomer), the optimum being different depending on the intended applications: the level of reinforcement expected on a bicycle tire, for example, is in known manner significantly lower than that required on a tire capable of traveling at high speed in a sustained manner, for example a motorcycle tire, a tire for passenger vehicle or utility vehicle such as Truck.
• siloxane polysulphide used as crosslinking agent in the rubber compositions of the invention therefore corresponds to the following general formula (I):
• This compound is characterized by the presence, in its molecule, of a polysulfide group S x (with x> 2, that is to say the disulfide group included) attached, via two silicon atoms, to a di-siloxane cycleSi-0-Si ⁇ structure (cycle). It can therefore be described as cyclic di-siloxane polysulfide.
• linear or branched radicals R preferably comprising from 1 to 18 carbon atoms, are more preferably chosen from alkyls, cycloalkyls or aryls, in particular
• radicals R there may be mentioned, by way of example, those chosen from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, 2-ethylhexyl, n-octyl, iso-octyl, cyclopentyl, cyclohexyl, 2-methylcyclohexyl, phenyl, toluyl, benzyl.
• radicals R which are identical or different, are C 1 -C 3 alkyls (namely methyl, ethyl, n-propyl, isopropyl), very particularly chosen from methyl and ethyl.
• the radicals Z substituted or unsubstituted, preferably having from 1 to 18 carbon atoms, are preferably hydrocarbon radicals, saturated or unsaturated, these Z radicals being able to be interrupted within the hydrocarbon chain by at least one heteroatom such that O, S or N.
• Particularly suitable are C 1 -C alkylene groups or C 6 -C 12 arylene groups, more particularly C 1 -C 10 alkylene.
• Particularly preferred compounds of formula (I) are those in which the radicals R, which are identical or different, are C 3 alkyl groups and the radicals Z, which are identical or different, are C ⁇ -C 4 alkylene (methylene, ethylene , propylene, butylene), in particular in C 2 -C 4 , with x more preferably greater than 2.
• x has an average value between 3 and 5, more preferably close to 4 (that is to say between 3.5 and 4.5) and Z is a C 2 alkylene - C 4 .
• the content of siloxane polysulfide is preferably greater than 0.5 phr, more preferably between 1 and 15 phr. Below the minimums indicated, the effect is likely to be insufficient, while beyond the recommended maximum there is generally no longer any improvement in crosslinking, while the costs of the composition increase; for these various reasons, this content of siloxane polysulphide is more preferably chosen to be between 3 and 12 phr.
• siloxane polysulfides previously described have been found to be sufficiently effective on their own for the crosslinking of a diene elastomer. Without this being limiting, they can advantageously replace, in the compositions of the invention, all of the sulfur and other usual sulfur donor agent (s).
• product B) it is subjected either to an alcoholysis by the action of an alcohol R'-OH (R 'hydrocarbon radical), or to a hydrolysis by the action of water in an inert organic solvent, in both cases in the presence of a organic base for trapping the acid halide formed, to obtain (hereinafter product B) either a monoalkoxysilane (in this case, R 'is the hydrocarbon radical in formula (B)), or a monohydroxysilane (in this case , R 'is H in formula (B)), of formula:
• a c) a sulphurization step is carried out on the product B by the action of a polysulphide, in order to obtain, as intermediate product (hereinafter product C), an alkoxysilane or hydroxysilane polysulphide of formula:
• the halogens (Hal) of the starting silane (product A) can be identical or different, preferably chosen from bromine and chlorine; chlorine is more preferably used.
• the starting halosilanes (products A) and their intermediate derivatives (products B or C) are liquid products; they can therefore be used as such or else in the diluted state in an appropriate solvent, during the implementation of the various stages of the synthesis process.
• the hydrolysis step of product A is carried out directly on the starting halogenated silane (product A), by the action of water in an inert organic solvent, for example an ether, and in the presence of an organic base intended to trap the acid halide formed.
• an inert organic solvent for example an ether
• the alcoholysis step of product A consists in replacing the halogen (Hal) carried by the silicon atom of product A by the alkoxyl group (OR ') of an alcohol, in the presence of a base organic agent intended to trap the acid halide released during the reaction.
• the hydrocarbon radical R 'of the alcohol (R'-OH) preferably contains 1 to 8 carbon atoms, it is more preferably chosen from C 1 -C 6 alkyls, more preferably still from C 1 alkyls, - C 3 , in particular methyl or ethyl.
• an amine can be used, preferably a tertiary amine such as triethylamine.
• the alcoholysis is carried out at a temperature which is preferably less than 15 ° C, more preferably less than 10 ° C.
• Sodium polysulphide Na ⁇ -, in particular Na ⁇ , Na ⁇ , Na ⁇ , Na ⁇ , NajSg, is preferably used, this polysulfide preferably being generated by the action of sulfur (S 8 ) on NajS.
• S 8 sulfur
• the preparation of such a polysulphide is carried out in a solvent, organic or not, such as for example water, alcohols, ketones or ethers, solvents in which the reagents are partially or completely soluble.
• the sulfurization step in the absence of any alcohol; then preferably working in the aqueous phase, more preferably in a two-phase water / organic solvent medium (for example toluene, xylene, benzene, heptane or the like), as described for example in documents EP-A-694 552 or US-A -5,405,985 relating to the synthesis of polysulphide alkoxysilanes.
• a phase transfer catalyst to which is more preferably added a salt of formula M' ⁇ al or M "SO 4 , M" being chosen from Li, Na, K and Hal being chosen from F, Cl and Br.
• the salt used is then preferably chosen from NaCl, NaBr, Na 2 SO 4 ; NaCl is even more preferably used.
• the amount of salt can vary, for example, from 10% by weight of the aqueous solution until the solution is completely saturated.
• the phase transfer catalyst is for example tetrabutyl ammonium bromide (TBAB).
• the sulfurization step is preferably carried out under an inert gas such as argon.
• the temperature of the reaction medium is not critical, one can for example work at room temperature; it is however preferred to operate hot to increase the reaction rate, for example between 60 ° C and 100 ° C or even up to the boiling point of the solvent.
• the molar ratio between the hydroxysilane or the alkoxysilane (product B) and the polysulfide is preferably adjusted so as to have a slight excess of polysulfide relative to the stoichiometric amount.
• the product B is itself preferably prediluted in the inert organic solvent such as an alcohol, a ketone or an ether.
• the salt (metal halide) which has formed is removed by filtration and the filtrate is freed from the organic solvent by vacuum distillation.
• the organic phase containing the product C is isolated if necessary and the reaction solvent is successively distilled under vacuum followed by the unreacted reagent B.
• the cychsation step on product C is carried out differently depending on whether it is a hydroxysilane polysulfide, in this case by a condensation step preferably
• P10-1441 / JR catalyzed by the presence of an acid or a base, or else of an alkoxysilane polysulfide, in this case by an acid or basic hydrolysis step, preferably of the acid type.
• product C diluted in an organic solvent, is introduced for example into a mixture consisting of an appropriate quantity of water, for example at the rate of two molar equivalents relative to the polysulphide used.
• reaction and a catalytic amount of catalyst such as an organic acid such as a carboxylic acid, more particularly trifluoroacetic acid.
• polysulfide siloxanes synthesized according to the process described above are in fact mixtures of polysulfides, with consequently an average value for x which is different from an integer value.
• the polysulfide siloxane previously described is preferably associated, in the crosslinking system proper, with a primary vulcanization accelerator, at a preferential rate of between 0.1 and 5 phr, more preferably of between 0.5 and 3 phr.
• such an accelerator must allow crosslinking of the rubber compositions in industrially acceptable times, while preserving a minimum safety period ("roasting time") during which the compositions can be shaped without risk. premature vulcanization ("roasting").
• Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur can be used.
• R 5 represents a hydrogen atom, a 2-mercaptobenzothiazyl group of formula:
• R 6 and R 7 independently represent a hydrogen atom, a 2-mercaptobenzothiazyl group (formula IN), a C 1 -C 4 alkyl group or a C 5 -C 8 cycloalkyl group, preferably comprising 6 links , said cycle possibly comprising at least one heteroatom such as S, O or ⁇ .
• Thiazole accelerators and preferential derivatives are notably chosen from the group consisting of 2-mercaptobenzothiazole, 2-mercapto-benzothiazyl disulfide, ⁇ -cyclohexyl-2-benzothiazyl sulfenamide, ⁇ , ⁇ -dicyclohexyl-2-benzothiazyl sulfenamide, N - ter-butyl-2-benzothiazyle sulfenamide, N-cyclohexyl-2-benzothiazyle sulfenimide, N-ter-butyl-2-benzothiazyle sulfenimide and mixtures of these compounds.
• the compounds of the thiuram family (formula VI) and the zinc dithiocarbamate derivatives (formula VII) are also suitable:
• R 8 , R 9 , R 10 and R each independently represent an alkyl group comprising from 1 to 8 carbon atoms, a benzyl group, a combination between R 8 and R 9 and a combination between R 10 and R 11 to form a cyclic pentamethylene group or a methyl-pentamethylene cyclic group and in which R 8 and R 9 and R 10 and R 11 are linked together.
• P10-1441 / JR Thiuram-type accelerators are especially chosen from the preferential group consisting of tetramethyl-thiuram monosulfide, tetramethyl-thiuram disulfide, tetraethyl-thiuram disulfide, tetrabutyl-thiuram disulfide, tetra-iso-butyl disulfide -thiuram, tetrabenzyl-thiuram disulfide and mixtures of these compounds.
• tetrabenzyl-thiuram disulfide is more preferably retained.
• the primary vulcanization accelerators used in the context of the present invention are even more preferably chosen from the group consisting of 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS”), N-cyclohexyl-2-benzothiazyl sulfenamide (abbreviated “CBS”), N, N-dicyclohexyl-2-benzothiazyle sulfenamide (abbreviated “DCBS”), N-ter-butyl-2-benzothiazyle sulfenamide (abbreviated “TBBS”), N-ter-butyl-2-benzothiazyl sulfenimide (abbreviated "TBSI”) and mixtures of these compounds.
• MBTS 2-mercaptobenzothiazyl disulfide
• CBS N-cyclohexyl-2-benzothiazyl sulfenamide
• DCBS N-dicyclohexyl-2-benzothiazy
• the rubber compositions in accordance with the invention also comprise all or part of the additives usually used in rubber compositions comprising a diene elastomer and intended for the manufacture of tires or semi-fine products for tires, such as, for example, plasticizers, protective agents such as anti-ozone waxes, chemical anti-ozonants, anti-oxidants, anti-fatigue agents, adhesion promoters, reinforcing resins as described for example in WO02 / 10269, peroxides and / or bismaleimides , or even sulfur and / or sulfur donor agents, various known secondary accelerators or vulcanization activators such as zinc oxide, stearic acid, guanidic derivatives (in particular diphenylguanidine), etc.
• plasticizers plasticizers
• protective agents such as anti-ozone waxes, chemical anti-ozonants, anti-oxidants, anti-fatigue agents, adhesion promoters, reinforcing resins as described for example in WO02 / 10269, per
• reinforcing filler in particular when it is a reinforcing inorganic filler, can also be associated, if necessary, with a conventional inorganic filler little or not reinforcing, for example particles of clays, bentonite, talc, chalk, kaolin.
• the reinforcing filler used is an inorganic filler
• agents for recovery of the reinforcing inorganic filler or more generally agents for aid in the use which are capable in known manner, thanks to an improvement in the dispersion of the inorganic filler in the rubber matrix and a reduction in the viscosity of the compositions, to improve their ability to be used in the raw state
• these agents being, for example, alkylalkoxysilanes, in particular alkyltriethoxysilanes, as for example example 1-octyl-triethoxysilane marketed by the company Degussa-H ⁇ ls under the name Dynasylan Octeo or 1-hexa-decyl-triethoxysilane marketed by the company Degussa-H ⁇ ls under the name Si216, polyols, polyethers (for example polyethylene glycols ), primary, secondary or tertiary amines (for example trialcano
• compositions are produced in suitable mixers, using two successive preparation phases well known to those skilled in the art: a first working or thermo-mechanical kneading phase (sometimes called a "non-productive" phase) at high temperature, up to a maximum temperature (noted T max ) of between 110 ° C and 190 ° C, preferably between 130 ° C and 180 ° C, followed by a second phase of mechanical work (sometimes referred to as the "productive" phase) at a lower temperature, typically less than 110 ° C., for example between 40 ° C. and 100 ° C., finishing phase during which the crosslinking or vulcanization system is incorporated.
• a first working or thermo-mechanical kneading phase (sometimes called a "non-productive" phase) at high temperature, up to a maximum temperature (noted T max ) of between 110 ° C and 190 ° C, preferably between 130 ° C and 180 ° C
• T max maximum temperature
• the productive phase finishing phase during which the cross
• the process for manufacturing the compositions according to the invention, having improved resistance to reversion comprises the following steps:
• crosslinking system comprises a siloxane polysulfide corresponding to the general formula (I) above.
• the first (non-productive) phase is carried out in a single thermomechanical step during which all the necessary basic constituents, any agents, are introduced into a suitable mixer such as a conventional internal mixer. covering or additional processing and other various additives, with the exception of the vulcanization system.
• a second thermomechanical working step can be added to this internal mixer, after the mixture has fallen and intermediate cooling (cooling temperature preferably less than 100 ° C.), with the aim of subjecting the compositions to a complementary thermomechanical treatment, in particular to improve still the dispersion, in the elastomeric matrix, of the reinforcing filler and other ingredients.
• the total duration of the kneading, in this non-productive phase is preferably between 2 and 10 minutes.
• the vulcanization system is then incorporated at low temperature, generally in an external mixer such as a cylinder mixer; the whole is then mixed (productive phase) for a few minutes, for example between 5 and 15 minutes.
• the final composition thus obtained is then calendered, for example in the form of a sheet, a plate or even extruded, for example to form a rubber profile used for the manufacture of semi-finished products such as treads, crown plies, sidewalls, carcass plies, heels, protectors, air chambers or internal rubber compounds for tubeless tires.
• the vulcanization (or baking) 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 baking temperature, the system vulcanization adopted, the vulcanization kinetics of the composition considered or for example of the size of the tire.
• vulcanization activators such as zinc oxide, stearic acid, guanidine derivatives, etc.
• the invention relates to the rubber compositions described above, both in the so-called “raw” state (ie, before baking) and in the so-called “cooked” or vulcanized state (ie, after crosslinking or vulcanization). .
• compositions in accordance with the invention can be used alone or as a blend (i.e., as a mixture) with any other rubber composition which can be used, for example, for the manufacture of tires.
• product D The above product of formula (II-1) (hereinafter called product D) is synthesized, in the examples which follow, according to the two different processes shown diagrammatically in FIG. 1 (hydrolysis or alcoholysis).
• product D The synthesis of product D is carried out according to a process in accordance with the invention in several stages, starting from chloropropyldimethylchlorosilane (hereinafter referred to as product A), via chloropropyldimethylsilanol (hereinafter referred to as product B) and bis polysulfide ( propyldimethylsilanol) (hereinafter referred to as product C).
• product A chloropropyldimethylchlorosilane
• product B chloropropyldimethylsilanol
• product C bis polysulfide
• the synthesis scheme applied is that shown in Figure 2 attached.
• product B can be prepared directly by hydrolysis of the starting product A, in an inert organic solvent (ether), in the presence of water as a hydroxyl and triethylamine donor intended to trap the acid. hydrochloric acid released.
• An excess of water is preferably introduced so as to promote the desired reaction, and avoid the condensation reaction of the silanol generated on the chlorosilane added.
• the use of a slight excess of triethylamine ensures total trapping of the hydrochloric acid, the residual triethylamine being distilled once the reaction is complete.
• the sodium polysulfide generated by insertion of sulfur in sodium sulfide NajS in an aqueous medium, comes to replace the chlorine atom of two molecules of product C in solution in toluene.
• the reaction is carried out in the presence of a phase transfer catalyst (TBAB) and sodium chloride NaCl.
• TBAB phase transfer catalyst
• reaction medium is then transferred to a separatory funnel so as to isolate the toluene phase, which is dried over magnesium sulfate after having been washed with water.
• organic solution is then filtered and taken up in ether before being distilled in a ball oven (40 ° C), in order to remove the residual chloropropyldimethylsilanol (product B).
• reaction medium is kept under stirring for 24 hours before being dried over magnesium sulfate, filtered and concentrated in vacuo.
• the disulfide S 2 level determined by NMR, is equal to approximately 18% of the polysulfide units.
• product D is carried out according to another process in accordance with the invention, in several stages, starting from chloropropyldimethylchlorosilane (product A), via the
• the first step consists of an alcoholysis which makes it possible to replace the chlorine carried by the silicon atom of product A by an ethoxyl group of ethanol, this reaction being carried out in the presence of triethylamine intended to trap the hydrochloric acid released during the reaction.
• the ice bath is removed while the stirring is continued at room temperature overnight, under a stream of argon.
• the GC analysis gas chromatography
• the reaction medium is then filtered through an Alhin tube in order to separate the product B 'in solution in ethanol from the triethylamine hydrochloride.
• the sodium polysulfide generated by insertion of sulfur in sodium sulfide Na-, S in an aqueous medium, comes to replace the chlorine atom of two molecules of the product (B ') in solution in toluene.
• the reaction is carried out in the presence of a phase transfer catalyst (TBAB) and sodium chloride NaCl.
• TBAB phase transfer catalyst
• reaction medium is then transferred to a separatory funnel so as to isolate the toluene phase, which is dried over magnesium sulfate after having been washed with water.
• organic solution is then filtered and taken up in ether before being distilled in a ball oven (40 ° C), in order to remove the residual chloropropyldimethylethoxysilane (product B '), ie 0.52 g.
• product B ' chloropropyldimethylethoxysilane
• product B ' chloropropyldimethylethoxysilane
• reaction medium is left under stirring at room temperature for 24 h, then dried over magnesium sulfate, filtered and concentrated in vacuo. 20.5 g of a very viscous pale yellow liquid are thus isolated, corresponding predominantly according to NMR analysis to the expected product, any traces of residual solvents which can be eliminated by subjecting the product to a vacuum of 200 mm Hg, at a temperature of 40 ° C, for 48 h.
• a diene elastomer (or mixture of diene elastomers) is introduced into an internal mixer, filled to 70% and whose initial tank temperature is approximately 60 ° C. , if applicable), the reinforcing filler, then the various other ingredients with the exception of the crosslinking system comprising at least the polysulfide siloxane (product D) and the primary accelerator.
• Thermomechanical work (non-productive phase) is then carried out in one or two stages (total mixing time equal to approximately 7 min), until a maximum "fall" temperature of approximately 165 ° C is reached.
• the mixture thus obtained is recovered, cooled, then the polysulfide siloxane (product D) and the accelerator are added to an external mixer (homo-finisher) at 40 ° C., mixing everything (productive phase) for 3 to 4 minutes.
• compositions thus obtained are then calendered in the form of plates (thickness of 2 to 3 mm) or of thin sheets of rubber for the measurement of their physical or mechanical properties, or extruded to form profiles which can be used directly, after cutting and / or assembly to the desired dimensions, for example as semi-finished products for tires, in particular as tire treads.
• This first test carried out using a laboratory mixer, aims to demonstrate that it is possible to crosslink, without addition of sulfur, a rubber composition using the product D previously synthesized.
• thermal stability resistance to reversion
• compositions tested are identical to the nature of the crosslinking agent except
• composition C-1 sulfur (1 pce); composition C-2: product D (3.7 pce); composition C-3: product D (7.5 pce).
• compositions C-1 is the witness of this test
• compositions C-2 and C-3 are in accordance with the invention and incorporate the polysulfide siloxane at the preferential rate of between 3 and 12 phr.
• Tables 1 and 2 give the formulation of the different compositions (Table 1 - rate of the different products expressed in pce), the rheometric properties (at 165 ° C), as well as the evolution of the rheometric couple after 2 hours at 165 ° C, representative of the thermal stability of the compositions.
• FIG. 4 shows the evolution of the rheometric torque (in dN.m) as a function of time (in min), for a temperature of 165 ° C., the curves C1 to C3 corresponding respectively to the compositions C-1 to C -3.
• FIG. 4 clearly confirms the ability of product D to crosslink the rubber compositions while offering them better resistance to reversion.
• compositions are prepared for this, similar to those of test 1 above, these compositions being identical to the nature of the crosslinking system except (sulfur or polysulfide siloxane, nature of the primary vulcanization accelerator).
• Composition C-4 is the control composition (sulfur plus sulfenamide accelerator), compositions C-5 to C-8 are in accordance with the invention and incorporate the polysulfide siloxane, with different accelerators.
• Tables 3 and 4 give the formulation of these compositions (Table 3 - rate of the various products expressed in pce), their rheometric properties at 165 ° C and the evolution of the rheometric couple after 2 hours at 165 ° C (reversion).
• This test was carried out on a larger mixer, compared to the previous tests, to allow a characterization of the rubber compositions in the raw state as in the cooked state, at the optimum baking at 150 ° C. and after prolonged cooking (2 hours at 150 ° C).
• composition C-9 (control): sulfur (1 pce); composition C-10 (invention): product D (7.5 pce).
• Tables 5 and 6 give the formulation of the two compositions, their properties before cooking and after cooking at 150 ° C.
• the thermal stability of the compositions is characterized by the evolution of the ⁇ MA100 and ⁇ MA300 modules.
• composition according to the invention C-10 compared with composition C-9, not only does not have any penalization of the properties in the raw state, but on the contrary reveals a clearly reduced Mooney plasticity, synonymous with an ability to the implementation in the raw state which is improved.
• the roasting times T5 are identical between the two compositions.
• compositions based on NR and BR are prepared, identical to the nature of the crosslinking system except (sulfur or polysulfide siloxane, accelerator rate).
• compositions C-11 and C-13 are control compositions (sulfur plus accelerator sulfenamide), the compositions C-12 and C-14 are those incorporating the polysulfide siloxane, therefore in accordance with the invention.
• compositions C-15 and C-17 are the control compositions (sulfur plus
• compositions C-16 and C-17 are those incorporating the polysulfide siloxane, therefore in accordance with the invention.
• the invention finds particularly advantageous applications in rubber compositions which can be used for the manufacture of finished articles or semi-finished products intended for any system for connecting the ground to motor vehicles, such as tires, internal safety supports for tires, wheels. , rubber springs, elastomeric joints, other suspension and anti-vibration elements.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Processes Of Treating Macromolecular Substances (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

Family

ID=29226129

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (6)

Citations (3)

Family Cites Families (7)

• 2003
  • 2003-04-15 EP EP03725031A patent/EP1499671A1/fr not_active Withdrawn
  • 2003-04-15 WO PCT/EP2003/003906 patent/WO2003087212A1/fr not_active Ceased
  • 2003-04-15 AU AU2003227625A patent/AU2003227625A1/en not_active Abandoned
  • 2003-04-15 JP JP2003584164A patent/JP4637487B2/ja not_active Expired - Fee Related
• 2004
  • 2004-09-21 US US10/945,812 patent/US7098260B2/en not_active Expired - Fee Related

Patent Citations (3)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events