MXPA97000588A - Rubber composition based on a polymerodenic that has a silanol function and quecomprende a organosil derivative - Google Patents

Abstract

The present invention relates to a sulfur vulcanizable rubber composition comprising at least one functionalized or modified diene polymer, and as a reinforcing filler, humi black or a mixture of carbon black and silica, characterized in that the diene polymer is a functionalized polymer having at the end of the chain a silanol function or a polysiloxane block having a silanol end, or modified along the chain by silanol functions, and in that the composition further comprises at least one organosilane compound having an amine or imine according to general formula I: wherein: Z represents a cyclic or non-cyclic primary or secondary amine function, an imine function or a polyamine radical, R1, R2, and R3, which may be identical or different, represent an alkyl, aryl, alkaryl or aralkyl group having from 1 to 12 carbon atoms and preferably having from 1 to 4 carbon atoms, n is an integer selected from the values 0, 1 and

Description

COMPOSITION OF RUBBER BASED ON A DIÉNICQ POLYMER THAT HAS A SILANOL FUNCTION AND THAT UNDERSTANDS A ORGAN ORGAN DERIVATIVE Field of the Invention The present invention relates to a rubber composition vulcanizable with sulfur and usable mainly for the manufacture of tire covers, which have improved hysteresis properties in the vulcanized state, comprising a functionalized or modified diene polymer and, as a reinforcing filler, black smoke or a mixture of carbon black and silica.

Background of the Invention Since fuel economy and the need to protect the environment have become a priority, it is appropriate to produce polymers possessing good mechanical properties and as low hysteresis as possible, in order to be able to use them in the form of Usable rubber for the manufacture of various semi-finished products that enter the REF: 23971 constitution of tire covers, such as for example sub-layers, rubber bands between different types of rubbers or coating of metal or textile reinforcements, rubber flanks or treads, and obtain tires with better properties, mainly that have a low rolling resistance. To achieve this objective, numerous solutions have been proposed consisting mainly of modifying the nature of the diene polymers and copolymers at the end of the polymerization by means of coupling agents or star structure or functionalization formers. Most of these solutions are essentially concentrated in the use of polymers modified with carbon black as a reinforcing filler, in order to obtain a good interaction between the modified polymer and the carbon black, since the use of reinforcing white fillers, and mainly Silica, has been revealed for some time inappropriate due to the low level of certain properties of the tires that employ these compositions. As an illustrative example of this prior art we can cite the patent US-B-4,550,142 which describes a rubber composition based on carbon black and a diene polymer functionalized with the aid of a benzophenone derivative, which has improved hysteresis properties. Patent US-B-5, 159, 009 which describes the use of carbon black modified by polysulfurized alkoxysilane derivatives in compositions based on diene polymers. Patent US-B-4, 820, 751 which describes a rubber composition usable in the manufacture of tires, comprising particular carbon black used with a silane coupling agent and which can be used with a minor amount of silica when this composition is intended to constitute a tread. Finally, the patent application EP-Al-0519188 which describes a composition intended to constitute a tread tire based on a diene rubber and carbon black modified by incorporation of particular organic silicon compounds to the master mix . Some solutions have also been proposed which relate to the use of silica as a reinforcing filler in compositions intended to constitute tire treads. Thus, patent application EP-A-0299074 discloses a rubber composition loaded with silica, based on a diene polymer functionalized with the aid of a silane compound having a non-hydrolyzable alkoxyl radical. Likewise, patent application EP-A-0447066 describing a silica-loaded composition containing a functionalized diene polymer with the aid of a halogenated silane compound can be cited. The silica compositions described in this prior art are not disclosed as usable for constituting tire treads. In fact, despite the improvement of the properties obtained with the use of said functionalized polymers, these remain insufficient to achieve the required level.

Description of the invention The subject of the present invention is therefore a diene rubber composition containing, as a reinforcing filler, carbon black or a mixture of carbon black and silica, usable in the manufacture of tires, in particular treads, which have improved hysteresis properties.

The invention also relates to treads of tires and tires which have reduced rolling resistance. The applicant company has surprisingly discovered that it is possible, without affecting the other properties, to greatly reduce the hysteresis of the diene rubber compositions which can be used in the manufacture of tire covers, mainly treads, which comprise as a black load of tires. smoke or a mixture of carbon black and silica, by using at least one functionalized diene polymer bearing at the end of the chain a silanol function or a polysiloxane block having a silanol end, or modified throughout the chain by silanol functional groups with at least one organosilane compound comprising one or more amine or i ina functions. The invention relates to a composition of vulcanizable rubber with sulfur comprising at least one functionalized or modified diene polymer, carbon black or a mixture of carbon black and silica as a reinforcing filler, characterized in that the diene polymer is a functionalized polymer that carries either at the end of the chain a silanol function or a polysiloxane block having a silanol end, or modified along the chain by silanol functions, and because it comprises at least one organosilane compound comprising one or more amine functions or imine that responds to general formula I: (ZJ-R'-Si (OR2) 3-n (R3) n wherein: Z represents a primary, secondary, cyclic or non-cyclic amine function, or an imine function or a polyamine moiety, R1, R2 and R3, identical or different, represent an alkyl, aryl, alkaryl or aralkyl group having 1 at 12 carbon atoms and preferably having 1 to 4 carbon atoms, n is an integer chosen from values 0, 1 or 2. Advantageously, a methyl or ethyl group can be chosen to represent R2. Nonlimiting examples of compounds of organosilanes of formula I may be mentioned aminopropyltrimethoxysilane, aminopropyltriethoxy silane, aminopropyl, amino- propildi etilmetoxisilano, dimethylether inopropil trimethoxysilane, methylaminopropyltrimethoxysilane, ethoxysilane aminoetilaminopropiltri, piperidino-propyltrimethoxysilane, pirrolidinopropiltrimetoxi silane piperazinopropiltrimetoxisilano, morpholino- propyltrimethoxysilane, imidazolinopropyltrimethoxysilane, pyrazolopropyltrimethoxysilane, triazolino-propyltrimethoxysilane and benzylidenepropyl aminotrimethoxysilane. These organosilane compounds of formula I can be used in amounts ranging from 0.1 to 10 parts by weight per 100 parts of functionalized polymers. Interesting are all functionalized polymers that carry a silanol function at the end of the chain or modified along the chain by silanol functions, but preferred are the diene polymers corresponding to the general formula II: wherein: R'1 and R'2, identical or different, represent an alkyl group having from 1 to 8 carbon atoms, x is an integer ranging from 1 to 1500 and preferably from 1 to 50, and P represents the chain of a diene polymer selected from the group represented by any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms, and any copolymer of one or more dienes conjugated to each other or to one or more vinylaromatic compounds , which have 8 to 20 carbon atoms. Suitable conjugated dienes are mainly 1,3-butadiene, 2,3-di- (Ci to C5 alkyl) -1, 3-butadienes, aryl-1,3-butadiene, 1,3-pentadiene, 2-hexadiene., etc. As vinylaromatic compounds are mainly interested in styrene, ortho-, meta-, para-methylstyrene, the commercial mixture "vinyltoluene", para-tert-butylstyrene, methoxystyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, etc ... The copolymers may contain between 99 % and 20% by weight of diene units and from 1% to 80% by weight of vinylaromatic units. The functionalized diene polymers bearing at the end of the chain a silanol function or a polysiloxane block having a silanol end, or modified along the chain by silanol functions can have any microstructure which is a function of the conditions of polymerization used. The polymers can be block, statistical, sequenced, micro-sequenced, etc., and prepared in mass, emulsion, dispersion or solution. When it comes to an anionic polymerization, the microstructure of these polymers can be determined by the presence or not of a modifying and / or randomizing agent and the amounts of modifying and / or randomizing agent employed. Preferred are polybutadienes and in particular those having a content in units of 1,2 comprised between 4% and 80% or those having a content of cis-1,4 greater than 80%, polyisoprenes, copolymers of butadiene-styrene and in particular those which they have a styrene content comprised between 4% and 50% by weight and more particularly between 20% and 40%, a 1,2-linkage content of the butadiene portion comprised between 4% and 65%, a content of trans-1 bonds , 4 comprised between 30% and 80%, butadiene-isoprene copolymers and mainly those having an isoprene content comprised between 5% and 90% by weight and a vitreous transition temperature <Tg) from -40 ° C to -80 ° C, isoprene-styrene copolymers and mainly those having a styrene content between 5% and 50% by weight and a Tg comprised between -25 ° C and -50 ° C C. In the case of the butadiene-styrene-isoprene copolymers, those having a styrene content between 5% and 50% by weight and more particularly between 10% and 40%, of isoprene comprised between 15% and 60% by weight, are of interest. weight and more particularly between 20% and 50%, of butadiene comprised between 5% and 50% by weight and more particularly comprised between 20% and 40%, of 1,2 units of the butadiene part comprised between 4% and 85%, of trans-1,4 units of the butadiene part. between 6% and 80%, of 1,2 units plus 3,4 of the isoprenic part comprised between 5% and 70% and of trans-1,4 units of the isoprhenic part comprised between 10% and 50%, and more generally any butadiene-styrene-isoprene copolymer having a Tg comprised between -20 ° C and -70 ° C. As the polymerization initiator, any known anionic or non-mono- or polyfunctional initiator can be used. However, an initiator containing an alkali metal, such as lithium, or alkaline earth metal, such as barium, is preferably used. Suitable organolithium initiators are those which comprise one or more carbonyl lithium bonds. Representative compounds are aliphatic organolithium compounds, such as ethyl lithium, n-butyllithium (n-BuLi), isobutyl lithium, polymethylenes with dilithium, such as 1,4-dilithiobutane, etc. Representative compounds containing barium are those described for example in patent applications FR-A-2, 302, 311 and FR-A-2,273,822 and certificates of addition FR-A-2,338,953 and FR-A-2, 340, 58 whose content is incorporated here. The polymerization is carried out, as is known, preferably in the presence of an inert solvent which can be for example an aliphatic or alicyclic hydrocarbon, such as pentane, hexane, heptane, iso-octane, cyclohexane or an aromatic hydrocarbon, such as benzene, toluene and xylene , The polymerization can be carried out continuously or discontinuously. Generally, the polymerization is carried out at a temperature comprised between 20 ° C and 120 ° C and preferably close to 30 ° C to 90 ° C. Of course, a transmetalization agent can also be added at the end of the polymerization to modify the reactivity of the end of the living chain. The functionalized or modified diene polymers used in the invention can be obtained by analogy by various methods. For example, you can choose one of the four ways described below. A first way is to react as described in Journal of Poly er Science, Part A, vol. 3, pp, 93-103 (1965), the living diene polymer with an organosilane functionalizing agent, preferably at the exit of the polymerization reactor and at an identical or different temperature, and preferably near, at the polymerization temperature, to form a diene polymer having a halogensilane function at the end of the chain and subjecting it, as described in the manual "Chemistry and Technology of Silicones, Academic Press, New York, NY (1968) p.95, to the action of a proton donor to obtain the diene polymer functionalized with silanol at the end of the chain The chaining of these two reactions has already been described by Messrs. Greber et Balciunas in Makromol, Chem. 69, pp. 193-205 (1963) As examples of organosilane functionalization agents capable of reacting with the living diene polymer, mention may be made of linear dihalogensilanes which correspond to the formula: wherein: Ri and R2, identical or different, represent an alkyl group having from 1 to 8 carbon atoms, X represents a halogen atom and preferably chlorine or bromine. As preferred dihalogensilane compounds, mention may be made of dichlorodimethylsilane and dichlorodiethyl silane. A second way is to react the living polymer with a cyclic polysiloxane functionalization agent to obtain a polymer having a SiO "end and this in a medium that does not allow the polymerization of said cyclopropylsiloxane. respond to the formula: wherein: - R3 and R4, identical or different, represent an alkyl group having from 1 to 8 carbon atoms, - m represents an integer from 3 to 8, and as preferred cyclic polysiloxane compounds, there may be mentioned hexamethyl -cyclotrisiloxane, trimethyltriethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopenta-siloxane and mixtures thereof. The polymer comprising a SiO "end is then reacted with a proton donor compound to lead the diene polymer functionalized with silanol at the end of the chain.A third way consists of preparing block copolymers comprising a block of polysiloxane which The block copolymers are obtained by the preparation, as described for example in US-B-3,483,270, US-B-3, 051, 684 and J. Appl. Poly. Sci. Vol. 8, p. 2707-2716 (1964) of a first block of a living diene polymer which is then reacted, in a polar medium, with a cyclic polysiloxane which is anionically polymerized to form a second block to lead to a block copolymer sequenced comprising a A polysiloxane block having one end (SiO ~) which is then reacted with a proton donor to conduct the block diene copolymer comprising a polysiloxane block having a silanol function at the end of the chain. A fourth way consists of preparing block copolymers comprising a block of polysiloxane having a silanol end by grafting 2 polymers, for example, by grafting a polysiloxane diluted or dissolved into a diene polymer having one end (SiX), X represents a halogen atom, the graft product then being reacted with a proton donor to drive the block copolymer comprising a polysiloxane block having a silanol end as described for example by Messrs. Greber and Balciunas in Makromol Chem, 79, pp. 149-160 (1964) or cited by Messrs. Plum and Atherton in the manual "Block Copolymers", Applied Science, England (1973) p. 339. Functionalized diene polymers carrying at the end of the chain a silanol functional group or a polysiloxane block having a silanol end, or modified along the chain by silanol functions, have a particular ability to be used to constitute rubber compositions, which mainly comprise silica as a reinforcing filler. This is what explains the surprise to the person skilled in the art that they improve the hysteresis properties of rubber compositions using said polymers, with the addition of organosilane compounds, when the filler is wholly or partly made up of carbon black. As carbon blacks which can be used in the rubber compositions according to the invention, all carbon blacks which are or are not modified by oxidation or by any other chemical treatment, especially all commercially available carbon blacks or conventionally used in tires and particularly on tire treads. As non-limiting examples of such blacks, mention may be made of blacks N134, N234, N375, N356, N339, etc. The carbon black can represent the totality of the reinforcing filler., but can also be used mixed with a white filler and in particular silica. All silicas are of interest, and can be either conventional silicas or the above-mentioned highly dispersible silicas, but the latter are preferred. "Highly dispersible silica" is understood to mean any silica that has an ability to deagglomerate and dispersion in a very important polymer matrix that can be observed by electron microscopy or optics, on thin layers. As non-limiting examples of said preferred highly dispersible silicas, mention may be made of those having a surface area of CTAB 450 m2 / g and particularly those described in patent applications EP-A-0157703 and EP-A-0520862, the content of which is incorporated herein, or Perkasil KS 340 silica from the Akzo company, silica Zeosil 1165 MP from the company Rhdne-Poulenc, silica Hi-Sil 2000 from the company PPG, silicas Zeopol 8741 and Zeopol 8745 from the company Huber. More preferred are silicas that have a specific surface • C >; _ 10 ° Y < 300 m2 / g and a specific surface BET > 100 and < 300 m2 / g and more preferably those having a specific surface BET / surface area ratio C > 1.0 and < 1,2, not importing its other additional characteristics, such as the oil intake, the porosity and the pore distribution, the medium diameter, the average projected area of the aggregates, etc ... and the physical state in which presents the silica, for example, microballoons, granules, powder, etc. Naturally by silica, it is also understood mixtures of different silicas. The silica can be used alone or in the presence of other white charges. The CTAB surface area is determined according to NFT Method 45007 of November 1987. The BET surface area is determined according to the BRUNAUER, EMMET, TELLER method described in "The Journal of the American Chemical Society, Vol, 80, page 309 (1938). ) "which corresponds to the NFT 45007 standard of November 1987. The proportion of the filler can vary from 30 to 100 parts of functionalized polymer bearing at the end of the chain a silanol function or a block of polysiloxane having one end of the chain. silanol, or modified along the chain by silanol functions. The proportion of silica in the mixture can vary from 1 to 200 parts by weight per 100 parts of carbon black, that is to say that the silica can represent from 1% to 70% by weight of the total reinforcing filler. The compositions according to the invention can comprise one or more functionalized diene polymers, which carry at the end of the chain a silanol function or a polysiloxane block having a silanol end, or modified along the chain by silanol functions as an elastomer, used exclusively or mixed with any other conventional diene polymer and mainly with any elastomer conventionally used in tire treads. As non-limiting of said conventional elastomers, mention may be made of natural rubber, non-functionalized diene polymers corresponding to the P chains of the functionalized or modified polymers corresponding to formula II or the same polymers but coupled or branched or functionalized, but with agents of functionalization, such as for example tin derivatives or benzophenone, such as those described for example in US-B-3, 393, 182, US-B-3,956,232, US-B-4, 026, 865, US-B -4, 550, 142 and US-B-5, 001, 196. When the conventional elastomer used in the mixture is natural rubber or one or more non-functionalized diene polymers, such as, for example, polybutadienes, polyisoprenes, butadiene-styrene copolymers or butadiene-styrene-isoprene, this elastomer may be present between 1 and 70 parts by weight per 100 parts of functionalized diene polymer bearing at the end of the chain a silanol function or a poly block siloxane having a silanol end, or modified along the chain with silanol functions. When the conventional elastomer used in the mixture is a polymer functionalized with a tin derivative or benzophenone, such as, for example, bis-dialkylamino-benzophenones, thiobenzophenone, chlorotrialkyltin, or a polymer which has been star-shaped by tin tetrachloride, this elastomer may be present at a ratio of 1 to 100 parts by weight per 100 parts by weight of functionalized polymer bearing at the end of the chain a silanol function or a polysiloxane block having a silanol end, or modified along the chain by silanol functions. The compositions according to the invention can obviously contain in the same way other constituents and additives commonly used in rubber mixtures, such as plasticizers, pigments, antioxidants, sulfur, vulcanization accelerators, dilution oils, one or more coupling agents or of binding of silica and / or one or more silica coating agents, such as polyols, amines, alkoxysilanes, etc. The subject of the present invention is also a novel process for preparing compositions of diene rubbers comprising as a reinforcing filler carbon black or a mixture of carbon black and silica, characterized in that incorporated by thermo-mechanical work into an elastomer comprising at least one functionalized diene polymer carrying at the end of the chain a silanol function or a block of polysiloxane having a silanol end, or modified along the chain by functions silanols and at least one organosilane compound comprising an amine or imine function corresponding to general formula I.

The incorporation of the organosilane compound of formula I is carried out in any suitable device, for example in an internal mixer or an extruder in a manner known per se. According to a first route, the elastomer or the mixture comprising at least one functionalized diene polymer bearing at the end of the chain a silanol function or a block of polysiloxane having a silanol end, or modified along the chain by silanol functions to a first phase of thermo-mechanical work after which the organosilane compound of formula I is added to the elastomer and the mixture of the two constituents is carried out in a second phase, and then the carbon black is added and the other constituents commonly used in rubber compositions intended for the manufacture of tires, with the exception of the vulcanization system, and the thermo-mechanical work is continued for an appropriate time. According to a second route, the elastomer comprising at least one functionalized diene polymer carrying at the end of the chain a silanol function or a block of polysiloxane having a silanol end, or modified along the chain is subjected to. with silanol functions and the organosilane compound of formula I in a first thermo-mechanical working phase and then the carbon black and the other constituents commonly used in the rubber compositions intended for the manufacture of tires are added with the exception of the system of vulcanization and thermo-mechanical work is continued for an appropriate time. According to a third route, the elastomer comprising at least one functionalized diene polymer bearing at the end of the chain a silanol function or a block of polysiloxane having a silanol end, or modified along the chain is subjected to silanols, the organosilane compound of formula I and the carbon black to a first thermo-mechanical working phase and then the other constituents usually used in rubber compositions intended for the manufacture of tires are added, with the exception of the system of vulcanization, and thermo-mechanical work is continued for an appropriate time. In the case where it is used as a reinforcing filler at the same time carbon black and silica, a thermo-mechanical work is carried out successively of the functionalized elastomer that carries at the end of the chain a silanol function or a block of polysiloxane that has an end of silanol, or modified along the chain by silanol functions, of the organosilane compound of formula I, of the silica and of the binding agent, after which the carbon black is incorporated. The thermo-mechanical work is preferably carried out in two thermal stages separated by a cooling step at a temperature below 100 ° C, as described in the patent application EP-A-0501227. To the mixture obtained according to any one of the embodiments, the vulcanization system is finally added as it is known per se in a finishing step before proceeding to the vulcanization of the composition. The invention is illustrated in a non-limiting manner by the following examples, in which the properties of the composition are evaluated as follows: Mooney viscosity: ML (1 + 4) at 100 ° C measured according to the ASTM standard: D-1646 .

- Shore A hardness: measurements made according to DIN 53505 standard. - 300% elongation modules (MA300), 100% (MA100) and 10% (MA10): measurements made according to ISO 37. - Scott breakage rates: measured at 20 ° C Forces for breaking (FR) in MPa Elongation at break (AR) in% - Hysteresis losses (PH) measured by rebound at 60 ° C in% - Dynamic shear properties: Measures depending on the deformation: carried out at 10 Hertz with a peak-peak deformation ranging from 0.15% to 50%. The non-linearity? G expressed in MPA is the difference of the shear modulus between 0.15% and 50% deformation. Hysteresis is expressed by the measurement of tgd at 7% deformation and at 23 ° C according to ASTM D2231-71 (reapproved in 1977).

Example 1 The aim of this control example is to compare the properties of a composition based on a functionalized polymer that carries at the end of the chain a silanol function with 2 compositions based on the same polymers but one non-functionalized and the other functionalized with an agent of functionalization known in the state of the art for providing interesting hysteresis properties within the framework of compositions reinforced with carbon black. In all tests of this example, the diene polymer is a butadiene-styrene copolymer having a polybutadiene vinyl bond content of 41% by weight, a styrenic bond content of 25% by weight and whose Mooney viscosity is 30. The butadiene-styrene copolymers used in the three compositions are: - for test A, a copolymer carrying a terminal silanol function, functionalized for this purpose with the aid of a cyclic siloxane functionalization agent (SBR-A), - for Test B, a functionalized copolymer (SBR-B) with n-Bu3SnCl as described in US-B-3, 956, 232 and 4,026,865. - for test C, a non-functionalized and methanol-terminated copolymer (SBR-C). For all tests, the copolymer is prepared in a reactor with a capacity of 32 liters with a turbine-type stirrer, in which toluene, butadiene, styrene and THF are continuously introduced in a mass ratio of 100: 10: 4, 3: 0.3 and a solution of 1030 micromoles of active n-BuLi per one hundred grams of monomers. The flow rates of the different solutions are calculated to provide an average time of stay of 45 minutes under strong agitation. The temperature is kept constant at 60 ° C. At the output of the reactor, the measured conversion is 88%. The copolymer is then either terminated with methanol, as in the case of SBR-C, or is functionalized during a subsequent step. The copolymer used in assay A is functionalized as described below. Hexamethylcyclotrisiloxane (D3) is added to the outlet of the reactor at the inlet of a static mixer at an active D3 / n-BuLi ratio of 0.48. The functionalization reaction is carried out at 60 ° C. Three minutes after the addition of the functionalizing agent, 0.5 parts per 100 parts of 4,4'-methylene-bis-2,6-di-tert-butyl-phenol elastomer are added as the oxidizing agent. The functionalized copolymer is recovered by the classical operation of steam separation of the solvent and then dried in an oven at 50 ° C. With the aid of the 3 copolymers SBR-A, B and C, 3 rubber compositions, respectively Al, Bl and Cl reinforced exclusively by carbon black according to the following formulation in which all the parts are expressed, are prepared in per se known manner. in weigh: Elastomer 100 Black N234 50 Aromatic oil 5 Zinc oxide 2.5 Stearic acid 1.5 Antioxidant (a) 1.9 Paraffin (b) 1.5 Sulfur 1.4 Sulfenamide (c) 1.4 (a): Antioxidant: N- (1,3-dimethyl-butyl) - N '-phenyl-p-phenylenediamine (b): paraffin: mixture of macro and microsocrystalline waxes (c): sulfenamide: N-cyclohexyl-2-benzothiazyl-sulfenamide The compositions are prepared in a single step to provide a mixture in a mixer filled internally up to 70%, whose temperature of the vat is 60 ° C and the average speed of the vanes is 45 revolutions per minute. The elastomer is introduced into the tank and then after an appropriate mixing time, the other constituents of the formulation are added with the exception of the vulcanization system and the thermo-mechanical work of kneading is continued until the fall temperature of 180 ° C . The mixture is recovered and then the sulfur and sulfenamide constituting the vulcanization system are added in a termination device by homogenization at 30 ° C. The vulcanization is carried out at 150 ° C for 40 minutes. The properties of the three compositions are compared with each other in both vulcanized and uncured state. The results are shown in Table I: (*) The deformation for this measure of hysteresis loss is 35% In view of the properties in a non-vulcanized state and in a vulcanized state, the composition comprising SBR-A carrying a silanol function at the end of the chain does not give significantly improved properties in relation to the composition Cl using SBR-C finished with methanol. Only the SBR-B functionalized with n-Bu3SnCl allows to obtain a composition Bl with hysteresis properties clearly reduced to a weak and strong deformation.

Example 2 The purpose of this example is to demonstrate the improvement of the properties of the compositions according to the invention. They are prepared with the 3 copolymers SBR-A, SBR-B and SBR-C, used in Example 1, 3 compositions respectively A2, B2 and C2 which differ from the previous ones only by the addition to the elastomer of an organosilane agent that responds to general formula I and which in this case is amino-propyltrimethoxysilane (APTSI) of formula: H2N- (CH2) 3-Si (OCH3) 3 The compositions are prepared according to the first route described above. The addition of one part by weight of the organosilane per 100 parts by weight of elastomer is effected 20 seconds after the beginning of the thermo-mechanical kneading operation.

The properties of the compositions obtained are shown in Table II. (*) the deformation for this measure of hysteresis loss is 35% In view of the properties in the vulcanized state, it is observed that the addition to the internal mixer of aminopropyltrimethoxysilane confers to the composition A2 comprising SBR-A carrying at the end of the chain a silanol function, reinforcing and hysteresis properties improved with relation to composition C2 using SBR-C terminated with methanol and of the same level as those obtained with composition B2 using SBR-B functionalized with n-Bu3SnCl. It is also observed that if the addition of aminopropyltrimethoxysilane strongly improves the properties of the composition A2 using SBR-A, it has practically no effect on the compositions that use SBR-B or SBR-C in this type of mixture based on black of smoke.

Example 3 This example shows through 4 tests relative to compositions according to the invention that employ SBR-A with 4 different organosilane agents that respond to the general formula I, which efficiently provide compositions with improved properties. The modifying agents chosen are therefore: - for test 1, aminopropyltrimethoxysilane (APTSI) of formula H2N- (CH2) 3-Si (0CH3) 3, - for test 2, methylaminopropyltrimethoxysilane (MAPTSI) of formula CH3-HN- ( CH2) 3-Si (OCH3) 3, for test 3, dimethylaminopropyltrimethoxysilane (DMAPTSI) of the formula: (CH3) 2- (CH2) 3-Si (OCH3) 3, - for test 4, imidazolinopropyltrimethoxysilane (IMPTSI) of formula: The properties of the 4 compositions are shown in Table III. ) the deformation for this measurement of loss of hystresis is 35% The results show that the various organosilane agents give the compositions improved hysteresis properties in relation to those presented by the composition using SBR-A in Example 1 and at the same level as those presented by composition Bl employing SBR-B in example 1. Likewise, the reinforcing properties of the 4 compositions according to the invention are improved.

Example 4 The purpose of this example is to show that the improvement of the properties is also obtained when the reinforcing filler is not exclusively carbon black, but consists of a mixture of carbon black and silica. They are prepared with the 3 polymers used in Example 1, 3 compositions A4, B4 and C4 whose formulation is as follows: Elastomer 100 APTS1 1 Silica * 30 Black N234 30 Aromatic oil 20 Bonding agent ** 2.4 Zinc oxide 2.5 Stearic acid 1.5 Antioxidant (a) 1.9 Paraffin (b) 1.5 Sulfur 1.1 Sulfenamide (c) 2 Diphenylguanidine 1.5 (*) Silica is a highly dispersible silica, in the form of microbeads, marketed by the Rhône-Poulenc company under the name Zeosil 1165 MP. (**) The binding agent is a polysulforated organosilane marketed by the company Degussa with the denomination SI69. (a): antioxidant: N- (1,3-dimethyl-butyl) -N'-phenyl-p-phenylenediamine (b): paraffin: mixture of macro and mierocristalin waxes (c): sulfenamide: N-cyclohexyl -2-benzothiazyl-sulfenamide Obtaining compositions A4, B4 and C4, which respectively use the copolymers SBR-A, SBR-B and SBR-C, are produced, according to a preferred embodiment, in two thermo-mechanical stages separated by a cooling phase. The first stage is carried out in an internal mixer with the same conditions of filling coefficient, temperature and vane speed as those indicated in example 1. The organosilane, in this case APTSI, is as in the previous example added to the elastomer 20 seconds after the beginning of the kneading of the elastomer and then, one minute after the addition of APTSI, the silica, the binding agent and the oil are added, then, a minute later, the carbon black followed by the stearic acid and the paraffin The thermo-mechanical work continues until reaching a fall temperature close to 160 ° C and then the elastomer block is recovered and cooled. The second stage is always carried out in the same internal mixer without changing the temperature and speed conditions of the pallets. The elastomer block is subjected to a thermo-mechanical work for an appropriate time to bring the temperature to approximately 100 ° C, then zinc oxide and antioxidant is added, after which the thermo-mechanical work is continued until a fall temperature next to 160 ° C and the mixture is recovered. To this mixture, the 3 components constituting the vulcanization system during a finishing step are incorporated per se. The vulcanization is carried out as in the other examples for 40 minutes at 150 ° C. The properties of the 3 compositions A4, B4 and C4 thus obtained are shown in Table IV and compared with the 3 control compositions A4-T, B4-T and C4-T using the same copolymers but devoid of APTSI.

(*) The deformation for this measure of hysteresis loss is 42% In view of the properties in the vulcanized state, it is observed that the addition in the internal mixer of APTSI confers to the composition A4 using SBR-A functionalized with silanol improved hysteresis properties not only in relation to those of the composition C4 that employs SBR-C finished with methanol, but even in relation to those of composition B4 using SBR-B functionalized by n-Bu3SnCl. Thus, the addition of organosilane agent that responds to formula I, to a polymer functionalized with silanol provides an improvement of the hysteresis properties even when the carbon black is not the only charge. Due to their improved hysteresis properties, the compositions according to the invention when used in a tire in the form of semi-finished products, mainly in the form of treads, allow the obtaining of tires having an improved rolling resistance. and as a result they reduce fuel consumption. It is noted that with respect to this date, the best method known to the applicant to carry out the present invention is that which is clear from the description of the present invention. Having described the present invention as above, the content of the following is claimed as property:

Claims (17)

1. Composition of vulcanizable rubber with sulfur, comprising at least one functionalized or modified diene polymer, carbon black or a mixture of carbon black and silica as a reinforcing filler, characterized in that the diene polymer is a functionalized polymer that carries at the end of the a silanol function chain or a polysiloxane block having a silanol end, or modified along the chain by silanol functions, and in that it comprises at least one organosilane compound comprising one or more amine or imine functions that responds to the general formula I: (Zí-R'-Si (OR2) 3-n (R3) n wherein: Z represents a primary, secondary, cyclic or non-cyclic amine function, or an imine function or a polyamine moiety, R1, R2 and R3, identical or different, represent an alkyl, aryl, alkaryl or aralkyl group having 1 to 12 carbon atoms and preferably having 1 to 4 carbon atoms, and n is an integer chosen from values 0, 1 or 2.

2. Composition according to claim 1, characterized in that R2 represents a methyl or ethyl group.

3. Composition according to any of claims 1 or 2, characterized in that the functionalized or modified diene polymer corresponds to the general formula II: wherein: R'1 and R'2, identical or different, represent an alkyl group having from 1 to 8 carbon atoms, x is an integer ranging from 1 to 1500, and P represents the chain of a polymer diene chosen from the group represented by any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms, and any copolymer of one or more diene conjugated to each other or to one or more vinylaromatic compounds, having from 8 to 20 carbon atoms.

4. Composition according to any of claims 1 to 3, characterized in that it also comprises natural rubber and / or polybutadiene and / or polyisoprene and / or a butadiene-styrene copolymer and / or a butadiene-styrene-isoprene copolymer.

5. Composition according to any one of claims 1 to 3, characterized in that it also comprises one or more polymers functionalized by bis-dialkylaminobenzophenones, thiobenzophenone or chlorotrialkyltin or starred with tin tetrachloride.

6. Composition according to any of claims 1 to 5, characterized in that the carbon black represents the entire reinforcing filler.

7. Composition according to any of claims 1 to 5, characterized in that the reinforcing filler is constituted by a mixture of carbon black and silica, the latter being able to represent up to 70% by weight of the total filler.

8. Composition according to claim 7, characterized in that the silica is a highly dispersible silica having a CTAB surface < 450 m2 / g,

9. Composition according to claim 8, characterized in that the silica has a specific surface BET > _ 100 and < _ 300 m2 / g and a surface area ratio BET to specific surface- CTBA > _ 1 and < _ 1.2.

10. Process for the preparation of a rubber composition based on diene elastomer, vulcanizable with sulfur, which has improved hysteresis properties, characterized in that it is incorporated by thermo-mechanical work into an elastomer comprising at least one functionalized diene polymer bearing at the end of the chain a silanol function or a block of polysiloxane having a silanol end, or modified along the chain by silanol functions, before the addition and incorporation of the other constituents usually used in vulcanizable sulfur-containing diene rubber compositions comprising the reinforcing filler, at least one organosilane compound comprising an amine or imine function corresponding to general formula I: wherein: Z represents a primary, secondary, cyclic or non-cyclic amine function, or an imine function or a polyamine moiety, R1, R2 and R3, identical or different, represent an alkyl, aryl, alkaryl or aralkyl group having 1 to 12 carbon atoms and preferably having 1 to 4 carbon atoms, and n is an integer chosen from values 0, 1 or 2.

11. Process according to claim 10, characterized in that the organosilane compound is used in the presence of the functionalized or modified diene elastomer before any thermo-mechanical work and because then the organosilane compound of formula I is incorporated into the elastomer by thermo-mechanical work.

12. Process according to claim 10, characterized in that the organosilane compound is added to the functionalized or modified diene elastomer after an initial thermo-mechanical working phase of the functionalized or modified diene elastomer and because the organosilane compound of formula I is incorporated into the Dienic elastomer functionalized or modified by thermo-mechanical work.

13. Process according to claim 10, characterized in that the functionalized or modified diene elastomer, the organosilane compound of formula I and the carbon black are subjected to a first thermo-mechanical working phase and then the other constituents usually used in the process are added. rubber compositions intended for the manufacture of tires, with the exception of the vulcanization system, and because the thermo-mechanical work is continued for an appropriate time.

14. Method according to claim 12, characterized in that when the reinforcing filler is constituted by carbon black and silica, they are successively added to the functionalized or modified diene elastomer that has undergone an initial phase of thermo-mechanical work, in the following order: organosilane compound of formula I and then the silica and the binding agent, and then the oil and finally the carbon black with the stearic acid and the anti-oxidant agent, then the elastomer block formed which is cooled is recovered, because in a second thermo-mechanical stage, the other ingredients usually used in said vulcanizable rubber compositions with sulfur are added to the elastomer block of the first stage with the exception of the vulcanization system, which is incorporated by thermo-mechanical work, because it is recovered the mixture and because in a finishing stage the vulcanization system is incorporated and the comp vulcanizable.

15. Tire having improved rolling resistance, comprising a sulfur vulcanizable rubber composition comprising at least one functionalized or modified diene polymer and, as a reinforcing filler, carbon black or a mixture of carbon black and silica, characterized in that the diene polymer is a functionalized polymer that carries at the end of the chain a silanol function or a polysiloxane block having a silanol end, or modified along the chain by silanol functions, and in that the composition further comprises at least one an organosilane compound comprising an amine or imine function corresponding to general formula I: < Z) -Rx-Si (OR2) 3 - "(R3) n wherein: Z represents a primary, secondary, cyclic or non-cyclic amine function, or an imine function or a polyamine moiety, R1, R2 and R3, identical or different, represent an alkyl, aryl, alkaryl or aralkyl group having 1 to 12 carbon atoms and preferably having 1 to 4 carbon atoms, and n is an integer chosen from values 0, 1 or 2.

16. Tire according to claim 15, characterized in that the composition enters into the constitution of the tread.

17. Tire tread, comprising a vulcanizable rubber composition containing at least one functionalized or modified diene polymer and, as a reinforcing filler, carbon black or a mixture of carbon black and silica, characterized in that the diene polymer is a functionalized polymer carrying at the end of the chain a silanol function or a polysiloxane block having a silanol end, or modified along the chain by silanol functions, and in that the composition further comprises at least one organosilane compound comprising an amine or imine function corresponding to general formula I: (Z) -R1-YES (OR) 3-n (R3) n wherein: Z represents a primary, secondary, cyclic or non-cyclic amine function, or an imine function or a polyamine moiety, R1, R2 and R3, identical or different, represent an alkyl, aryl, alkaryl or aralkyl group having 1 to 12 carbon atoms and preferably having 1 to 4 carbon atoms, and n is an integer chosen from values 0, 1 or 2.