Rubber composition comprising a highly saturated diene elastomer

Abstract

The present invention relates to a rubber composition based on at least one elastomeric matrix comprising predominantly a highly saturated diene elastomer, which highly saturated diene elastomer is a copolymer of ethylene and a 1,3-diene in which the ethylene units represent at least 50% by mole of the monomer units of the copolymer, a reinforcing filler, a vulcanizing system, a functional liquid butadiene polymer, which polymer is a liquid butadiene polymer functionalized along the chain by pendant alkoxysilyl functions, optionally totally or partially hydrolyzed, having a number-average molar mass (Mn) greater than or equal to 1000 g / mol, and a non-functional liquid butadiene polymer, having a number-average molar mass (Mn) greater than or equal to 1000 g / mol.

Description

Title of the invention: Rubber composition comprising a highly saturated diene elastomer technical field

[0001] The field of the present invention is that of highly saturated diene elastomer-based rubber compositions intended for use in a tire, particularly in its tread. Previous technique

[0002] The use of highly saturated diene elastomers is known in the manufacture of tires. For example, the Applicant described ethylene and 1,3-butadiene copolymers and their application in a tire tread in document WO2014114607A1. This document indicates that the use of these copolymers in the tread results in good wear resistance and rolling resistance properties for the tire.

[0003] Tire manufacturers are constantly seeking ways to improve tire performance. This research involves continuously improving the properties of the rubber compounds used in tire manufacturing. However, tire compounds generally represent a compromise between properties. Therefore, it is a constant objective for compound designers to ensure that improvements in certain properties do not come at the expense of others.

[0004] In the field of tires comprising a highly saturated diene elastomer tread, discussed above, there is a need, particularly under certain heavy-load transport conditions, for rubber compositions offering an improved compromise between tear resistance, stiffness, and hysteresis. Specifically, the aim is to increase stiffness for better wear resistance and reduce hysteresis to minimize rolling resistance, while improving or at least maintaining good tear resistance. Description of the invention

[0005] Continuing its efforts, the Applicant has found a rubber composition that meets this need in the field of application of highly saturated diene elastomers to rubber compositions for tires, and in particular for the tread. Most notably, the Applicant has found, unexpectedly, a rubber composition that combines the use of a highly saturated diene elastomer with the use of a liquid polymer of Functional butadiene, a butadiene polymer functionalized along its chain with alkoxysilyl groups, is combined with a liquid homopolymer of non-functional butadiene. This improves hysteretic properties and stiffness while maintaining, or even enhancing, the tear resistance of the composition, compared to compositions not containing these combined low molecular weight polybutadienes. These properties suggest that the tire will have good rolling resistance and durability, particularly when carrying heavy loads.

[0006] Thus, a first object of the invention is a rubber composition based on at least - an elastomeric matrix comprising predominantly a highly saturated diene elastomer, - a reinforcing load, - a vulcanization system and - a functional liquid butadiene polymer, which polymer is a liquid butadiene polymer functionalized along the chain by pendant alkoxysilyl groups, optionally partially or totally hydrolyzed, and - a non-functional liquid butadiene polymer.

[0007] Another object of the invention is a pneumatic or non-pneumatic tire comprising a rubber composition according to the invention, preferably in its tread. Summary of the invention

[0008] The invention, described in more detail below, relates to at least one of the embodiments listed in the following points:

[0009] 1. Rubber composition based on at least - an elastomeric matrix comprising predominantly a highly saturated diene elastomer, which highly saturated diene elastomer is a copolymer of ethylene and a 1,3-diene in which the ethylene units represent at least 50% by mole of the monomer units of the copolymer, - a reinforcing filler, - a vulcanization system, - a functional liquid butadiene polymer, which functional liquid butadiene polymer is a liquid butadiene polymer functionalized along the chain by pendant alkoxysilyl groups, optionally partially or totally hydrolyzed, having a number-average molar mass (Mn) greater than or equal to 1000 g / mol, and

[0010] - a non-functional liquid butadiene polymer, having a molar mass number average (Mn) greater than or equal to 1000 g / mol.

[0011] 2. Rubber composition according to embodiment 1, wherein the ethylene units represent 50% to 95% by mole of the monomer units of the copolymer.

[0012] 3. Rubber composition according to any one of the preceding embodiments, in which the ethylene units represent at least 60% by mole of the monomer units of the copolymer, preferably from 65% to 90% by mole of the monomer units of the copolymer.

[0013] 4. Rubber composition according to any one of the preceding embodiments, in which the 1,3-diene is 1,3-butadiene, isoprene, myrcene or [3-famesene, or a mixture of myrcene and [3-farnesene, preferably 1,3-butadiene.

[0014] 5. Rubber composition according to any one of the preceding embodiments, in which the copolymer of ethylene and a 1,3-diene is a copolymer of ethylene and 1,3-butadiene.

[0015] 6. Rubber composition according to any one of the preceding embodiments, in which the copolymer of ethylene and a 1,3-diene is a statistical copolymer.

[0016] 7. Rubber composition according to any one of the preceding embodiments, in which the proportion of the highly saturated diene elastomer varies in a range of 60 to 100 pc, preferably 80 to 100 pc and most preferably 90 to 100 pc.

[0017] 8. Rubber composition according to any one of the preceding embodiments in which the functional liquid butadiene polymer is functionalized along the chain by pendant alkoxysilyl functions, optionally partially or totally hydrolyzed.

[0018] 9. Rubber composition according to any one of the preceding embodiments in which the alkoxysilyl functions correspond to the formula Si(OR)nR'3 n, in which each R, independently of the others, designates a hydrogen atom or an alkyl in Ci-Cio, preferably in CrC4, each R', independently of the others, designates an alkyl in Ci-Cio, preferably in Ci-C4, and n is an integer from 1 to 3, preferably 3.

[0019] 10. Rubber composition according to any one of the preceding embodiments in which the alkoxysilyl functions are functions corresponding to the formula Si(OR)3, in which each R, independently of the others, designates a hydrogen atom or an alkyl in Ci-Ci0, preferably in CrC4, preferably an alkyl in CrC4.

[0020] 11. Rubber composition according to any one of the preceding embodiments in which the alkoxysilyl functions are trimethoxysilyl or triethoxysilyl functions, optionally partially or totally hydrolyzed.

[0021] 12. Rubber composition according to any one of the preceding embodiments in which the functional liquid butadiene polymer and the non-functional liquid butadiene polymer independently have a proportion in the rubber composition in the range of 1 to 50 parts per annum, preferably 2 to 30 parts per annum, and preferably still 5 to 15 parts per annum.

[0022] 13. Rubber composition according to any one of the preceding embodiments in which the functional butadiene liquid polymer has a Tg greater than -115°C and less than or equal to -60°C, more preferably from -80°C to -110°C, measured by DSC according to ASTM D3418 (1999).

[0023] 14. Rubber composition according to any one of the preceding embodiments in which the functional liquid butadiene polymer and the non-functional liquid butadiene polymer independently have a number average molar mass greater than or equal to 1000 g / mol and less than or equal to 50000 g / mol, preferably less than or equal to 30000 g / mol, even more preferably less than or equal to 10000 g / mol, measured by SEC.

[0024] 15. Rubber composition according to any one of the preceding embodiments in which the functional liquid butadiene polymer and the non-functional liquid butadiene polymer independently exhibit a number-average molar mass ranging from 1000 g / mol to 10000 g / mol.

[0025] 16. Rubber composition according to any one of the preceding embodiments in which the functional liquid butadiene polymer comprises motifs of formula (a) and (c): \(idov.....If | \ w

[0027] each R1 independently representing a hydrogen atom or an alkyl radical in the form Ci-Ci o, preferably an alkyl in the form CrC4 each R2 independently representing an alkyl radical in the form of Ci-Cio, preferably in CrC4 m is an integer and is equal to 1, 2 or 3, preferably 3.

[0028] 17. Rubber composition according to the preceding embodiment in which the functional liquid butadiene polymer includes a rate of formula motifs (b) ranging from 0% to 10% molar relative to polybutadiene, preferably from 0 to 5% molar.

[0029] 18. Rubber composition according to any one of embodiments 16 and 17 in which the functional liquid butadiene polymer does not include a vinyl-1,2 motif of formula (b). - / ch^hA-^ I

[0030] 19. Rubber composition according to any one of embodiments 16 to 18 in in which the functional liquid butadiene polymer is exclusively made up of motifs (a) and motifs (c).

[0031] 20. Rubber composition according to any one of the preceding embodiments in which the functional liquid butadiene polymer and the non-functional liquid butadiene polymer independently exhibit a Tg greater than -115°C and less than or equal to -60°C, more preferably from -80°C to -110°C, measured by DSC according to ASTM D3418 (1999).

[0032] 21. Rubber composition according to any one of the preceding embodiments in which the sum of the rates of functional liquid butadiene polymer and non-functional liquid butadiene polymer is at most 80%, preferably at most 50%, and preferably even more at most 30%.

[0033] 22. Rubber composition according to any one of the preceding embodiments in which the proportion of each of the two functional and non-functional liquid butadiene polymers is at least 1 pc, preferably at least 2 pc.

[0034] 23. Rubber composition according to any one of the preceding embodiments in which the mass ratio of functional liquid butadiene polymer to non-functional liquid butadiene polymer varies from 4:1 to 1:4, preferably from 1.5:1 to 1:1.5.

[0035] 24. Rubber composition according to any one of the preceding embodiments in which the reinforcing filler comprises at least one silica, one carbon black or a mixture of silica and carbon black.

[0036] 25. Rubber composition according to any one of the preceding embodiments in which the reinforcing filler comprises silica as the major reinforcing filler.

[0037] 26. Rubber composition according to any one of the preceding embodiments in which the reinforcing load rate is within a range of 5 to 150 pce.

[0038] 27. Rubber composition according to any one of the preceding embodiments in which the silica content is within a range of 20 to 60 parts per cent.

[0039] 28. Pneumatic or non-pneumatic bandage comprising a composition of rubber according to any of the previous designs.

[0040] 29. Pneumatic or non-pneumatic bandage according to the preceding embodiment comprising a rubber composition according to any one of embodiments 1 to 28 in all or part of its tread. Definitions

[0041] The term "liquid butadiene polymer" according to the invention means a more or less viscous butadiene polymer which is liquid at room temperature (approximately 23°C below atmospheric temperature), that is to say, as a reminder, having the capacity to take the shape of its container in the future.

[0042] The expression "composition based on" means a composition comprising the mixture and / or the in situ reaction product of the different constituents used, some of these constituents being able to react and / or being intended to react with each other, at least partially, during the different phases of manufacturing the composition; the composition can thus be in a totally or partially crosslinked state or in a non-crosslinked state.

[0043] By the expression "part by weight per hundred parts by weight of elastomer" (or pce), it is to be understood in the sense of the present invention, the part, by mass per hundred parts by mass of elastomer.

[0044] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​going from more than a to less than b (that is to say, bounds a and b excluded) while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​going from a to b (that is to say, including the strict bounds a and b).

[0045] In this application, "all the monomer units of the elastomer" or "all the monomer units of the elastomer" means all the repeating units constituting the elastomer that result from the insertion of the monomers into the elastomer chain by polymerization. Unless otherwise specified, the contents of a monomer unit or repeating unit in the highly saturated diene elastomer are given as a molar percentage calculated on the basis of all the monomer units of the elastomer.

[0046] In the present, the contents of a monomer unit or repeating motif in a liquid butadiene polymer are given as a molar percentage calculated on the basis of the polybutadiene part of the liquid polymer.

[0047] When referring to a "major" compound, for the purposes of this invention, it is understood that this compound is the majority among the compounds of the same type in the composition; that is, it is the one that represents the largest quantity by mass among the compounds of the same type. Thus, for example, a major elastomer is the elastomer representing the greatest mass relative to the total mass of the elastomers in the composition. Similarly, a so-called major filler is the one representing the greatest mass among the fillers in the composition. By way of example, in a system comprising a single elastomer, this elastomer is the major component for the purposes of this invention; and in a system comprising two elastomers, the major elastomer represents more than half of the mass of the elastomers. Conversely, a "minor" compound is a compound that does not represent the largest mass fraction among the compounds of the same type.Preferably, "major" means a mass proportion of more than 50%; when the compound represents 100% by mass, it is also described as "major".

[0048] The compounds mentioned in the description may be of fossil origin or bio-based. In the latter case, they may be partially or totally derived from biomass or obtained from renewable raw materials derived from biomass. Similarly, the compounds mentioned may also come from the recycling of materials already used, that is to say, they may be partially or totally derived from a recycling process, or obtained from raw materials themselves derived from a recycling process. This includes, in particular, polymers, fillers, etc.

[0049] Unless otherwise indicated, as is the case in the examples presented below, the glass transition temperature (Tg) values ​​described herein are measured in a known manner by DSC (Differential Scanning Calorimetry) according to ASTM D3418 (1999). Detailed description of the invention 1- Elastomer matrix

[0050] By "elastomer matrix", we mean all the elastomers in the composition.

[0051] According to the invention, the elastomeric matrix comprises predominantly at least one highly saturated diene elastomer, namely a copolymer containing ethylene units and 1,3-diene units (hereinafter referred to as "the copolymer").

[0052] The highly saturated diene elastomer useful for the purposes of the invention is a copolymer, preferably a statistical one. A "statistical copolymer" is understood to be a copolymer in which the sequential distribution of the monomer units obeys a known statistical law.

[0053] The highly saturated diene elastomer useful for the purposes of the invention is a copolymer comprising ethylene units resulting from the polymerization of ethylene. As is known, the term "ethylene unit" refers to the -(CH2-CH2)- motif resulting from the insertion of ethylene into the elastomer chain. The highly saturated diene elastomer is rich in ethylene units, since the ethylene units represent at least 50% by mole of all the monomer units of the elastomer. The maximum proportion of ethylene units is determined by the elastomeric nature of the polymer; this proportion is preferably at most 95% by mole, more preferably at most 90% by mole, and even more preferably at most 85% by mole. Thus, preferentially, the highly saturated diene elastomer comprises 50% to 95% molar ethylene units, molar percentage calculated on the basis of all the monomer units of the highly saturated diene elastomer.

[0054] Preferably, the highly saturated diene elastomer comprises at least 60 mol% of ethylene units. In other words, the ethylene units preferably represent at least 60 mol% of all the monomer units of the highly saturated diene elastomer. Even more preferably, the ethylene units represent at least 65 mol% of all the monomer units of the highly saturated diene elastomer, and more preferably at least 70 mol% of all the monomer units of the highly saturated diene elastomer. Even more preferably, the highly saturated diene elastomer comprises from 65% to 90 mol% of ethylene units, the mol% being calculated on the basis of all the monomer units of the highly saturated diene elastomer.

[0055] The highly saturated diene elastomer according to the invention being a copolymer of ethylene and a 1,3-diene, it also comprises 1,3-diene units resulting from the polymerization of a 1,3-diene. As is known, the expression "1,3-diene unit" refers to the units resulting from the insertion of 1,3-diene.

[0056] The 1,3-diene units are those, for example, of a 1,3-diene having 4 to 24 carbon atoms.

[0057] Suitable 1,3-dienes include butadiene, isoprene, 2,3-di(C1-alkyl)-1,3-butadiene such as, for example, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene or 2-methyl-3-isopropyl-1,3-butadiene, aryl-1,3-butadiene such as phenyl-1,3-butadiene, and 1,3-pentadiene. A 1,3-diene with the formula CH2=CR-CH=CH 2, in which R represents a hydrocarbon chain having 3 to 20 carbon atoms, such as for example a linear monoterpene (Ci0Hi6), like myrcene, a linear sesquiterpene (C15H24), like [3-famesene etc.

[0058] The highly saturated diene elastomer is preferably a copolymer of ethylene and a 1,3-diene among 1,3-butadiene, isoprene, myrcene, [3-farnesene and a mixture of myrcene and [3-farnesene.

[0059] Preferably, the 1,3-diene is 1,3-butadiene or isoprene, more preferably 1,3-butadiene, in which case the highly saturated diene elastomer is a copolymer of ethylene and 1,3-butadiene, statistically preferred.

[0060] According to the invention, particularly when the first 1,3-diene is 1,3-butadiene or a mixture of 1,3-butadiene and at least one other 1,3-diene, the highly saturated diene elastomer may further contain 1,2-cyclohexanediyl units. The presence of these cyclic structures in the copolymer results from a very specific insertion of ethylene and 1,3-butadiene during polymerization. The content of 1,2-cyclohexanediyl units in the copolymer varies according to the respective contents of ethylene and 1,3-butadiene in the copolymer. The copolymer preferably contains less than 15 mole percent of 1,2-cyclohexanediyl unit units.

[0061] The highly saturated diene elastomer useful for the purposes of the invention can be obtained by various synthetic methods known to those skilled in the art, particularly depending on the desired microstructure of the highly saturated diene elastomer. Generally, it can be prepared by copolymerization of at least one 1,3-diene, preferably 1,3-butadiene, and ethylene, according to known synthetic methods, particularly in the presence of a catalytic system comprising a metallocene complex. Examples include catalytic systems based on metallocene complexes, which are described in documents EP 1 092 731, WO 2004035639, WO 2007054223 and WO 2007054224, as well as WO2020070442, WO2020070443 and WO2020074804 on behalf of the Applicant.The highly saturated diene elastomer, including when statistical, can also be prepared by a process using a preformed catalytic system such as those described in documents WO 2017093654 Al, WO 2018020122 Al and WO 2018020123 AL. The highly saturated diene elastomer is statistical according to an embodiment of the invention.

[0062] The highly saturated diene elastomer useful for the needs of the invention may consist of a mixture of highly saturated diene elastomers which differ from each other by their microstructures or by their macrostructures.

[0063] According to the invention, the proportion of highly saturated diene elastomer in the rubber composition is preferably at least 50 parts by weight per hundred parts of elastomer in the rubber composition (wt). Preferably, The percentage of highly saturated diene elastomer in the rubber composition varies in the range of 60 to 100 parts per million, preferably from 80 to 100 parts per million. More preferably, it varies in the range of 90 to 100 parts per million.

[0064] In addition, the elastomer matrix of the composition of the invention may include at least one other elastomer, in a minor quantity. In particular, we note diene elastomers known to those skilled in the art for their use in the field of tires, such as polybutadiene (abbreviated "BR"), synthetic polyisoprene (IR), natural rubber (NR), butadiene copolymers such as butadiene-styrene copolymer (SBR), isoprene copolymers and mixtures of these elastomers. 2- Functional liquid butadiene polymer

[0065] The composition of the invention comprises a functional liquid butadiene polymer, which polymer is a liquid butadiene polymer functionalized along the chain by pendant alkoxysilyl functions, having a number-average molar mass (Mn) greater than or equal to 1000 g / mol.

[0066] The term "butadiene polymer" means a homopolymer or copolymer of butadiene, in other words, a diene polymer selected from the group consisting of polybutadienes, various butadiene copolymers, and mixtures of these polymers. Among butadiene copolymers, particular examples include copolymers of butadiene and a vinylaromatic monomer, preferably styrene.

[0067] Preferably, the functional liquid butadiene polymer is a liquid polybutadiene.

[0068] According to the invention, the functional liquid butadiene polymer is a liquid butadiene polymer functionalized along the chain by pendant alkoxysilyl groups. By "chain-functionalized polymer" is understood, in a known manner, a polymer having several pendant alkoxysilyl functional groups, distributed along the main chain of the elastomer excluding its ends.

[0069] By "alkoxysilyl function, optionally partially or totally hydrolyzed", is meant a function corresponding to the formula -Si(OR)nR'3, where n, each R, independently of the others, represents a hydrogen atom or an alkyl radical in the form of Ci-Cl₂, preferably CrC₄, each R', independently of the others, designates an alkyl in the form of Ci-Cl₂, preferably CrC₄, and n is an integer from 1 to 3, preferably 3. Preferably, the alkoxysilyl function is a function corresponding to the formula -Si(OR)₃, R being as defined above, preferably an alkyl in the form of Ci-Cl₂, preferably CrC₄. Even more preferably, the alkoxysilyl function is a trimethoxysilyl or triethoxysilyl function, optionally partially or totally hydrolyzed.

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079] Thus, advantageously, the liquid butadiene polymer functionalized along the chain by pendant alkoxysilyl functions is a functionalized liquid polybutadiene bearing along the chain pendant trialcoxysilyl functions, preferably trimethoxysilyl or triethoxysilyl, optionally partially or totally hydrolyzed. According to the invention, the functional liquid butadiene polymer has a number-average molar mass (Mn) greater than or equal to 1000 g / mol and preferably less than or equal to 50,000 g / mol, more preferably less than or equal to 30,000 g / mol, and more preferably less than or equal to 10,000 g / mol. Thus, according to certain embodiments, the functional liquid butadiene polymer has a number-average molar mass (Mn) ranging from 1000 g / mol to 1000 g / mol. Preferably, the functional liquid butadiene polymer according to the invention also has a Tg greater than -115°C and less than or equal to -60°C, more preferably from -80°C to -110°C. According to the invention, the various preferred characteristics above of the liquid butadiene polymer are combinable with each other. According to certain embodiments of the invention, the functional liquid butadiene polymer may comprise motifs (a) and (c) corresponding to the following formulas: (a) . , and (c) ' : / THAT \ s / \ each R1 independently representing a hydrogen atom or an alkyl radical in the form Ci-Cio, preferably an alkyl in the form CrC4, each R2 independently representing an alkyl radical in Ci-Cio, preferably in CrC4 m is an integer and is equal to 1, 2 or 3, preferably 3. According to certain preferred embodiments of the invention, each R1 represents a methyl radical or each R1 represents an ethyl radical. According to these embodiments of the invention, m is 3 and each R1 represents a methyl radical or each R1 represents an ethyl radical. Preferably, m is 3 and each R1 represents an ethyl radical. According to certain embodiments of the invention, the functional butadiene liquid polymer comprises at most 10 mol% of a vinyl-1,2 repeating unit of formula (b), preferably from 0 to 5 mol%. According to certain embodiments of the invention, The functional liquid butadiene polymer does not include a 1,2-vinyl motif, corresponding to formula (b):

[0080] (b) \ «h /

[0081] The microstructure of the liquid polymer is determined by 'H NMR analysis as described below in the section reserved for examples.

[0082] According to certain embodiments of the invention, the functional liquid butadiene polymer is essentially made up of motifs (a) and motifs (c).

[0083] These different embodiments can be combined with each other. Thus, according to certain particular embodiments of the invention, the functional liquid butadiene polymer is essentially made up of motifs (a) and motifs (c), in which m is 3 and each R1 represents a methyl radical or each R1 represents an ethyl radical, preferably each R1 represents an ethyl radical.

[0084] The liquid butadiene polymer functionalized along the chain by alkoxysilyl functions can be obtained in a simple and known way by hydrosilylation of the dangling carbon-carbon double bonds of the vinyl-1,2 motifs of the butadiene part of a liquid butadiene polymer.

[0085] According to certain embodiments of the invention, the functional liquid butadiene polymer preferably comprises at least 2 alkoxysilyl functions per polymer chain, more preferably at least 5 alkoxysilyl functions per polymer chain.

[0086] According to certain embodiments of the invention, the functional liquid butadiene polymer preferably comprises 2 to 30 alkoxysilyl functions per polymer chain.

[0087] Such polymers are described for example in documents EP3466996A1 and EP3293217A1.

[0088] The Tg of the liquid polymer is measured by DSC according to ASTM D3418 (1999). The macrostructure (Mw, Mn and IP) of the functional butadiene liquid polymer is determined by size exclusion chromatography (SEC): tetrahydrofuran solvent; temperature 35°C; concentration 1 g / L; flow rate 1 mL / min; solution filtered through a 0.45 µm porosity filter before injection; Moore calibration with polystyrene standards; set of 3 "WATERS" columns in series ("STYRAGEL" HR4E, HR1 and HR0.5); detection by differential refractometer ("WATERS 2410") and its associated operating software ("WATERS EMPOWER").

[0089] Functional liquid butadiene polymers useful for the needs of the invention can be found commercially under the name for example "X-12-1267B", "X-12-1267B-ES" and "X-12-1287A" marketed by the company Shin-Etsu.

[0090] According to any one of the embodiments of the invention, the proportion of liquid butadiene polymer functionalized along the chain by alkoxysilyl groups is advantageously greater than or equal to 1 pc, preferably within a range of 1 pc to 50 pc, more preferably from 2 to 30 pc, more preferably from 3 to 20 pc, and more preferably from 5 pc to 15 pc.

[0091] The liquid butadiene polymer functionalized along the chain by alkoxysilyl functions can be a mixture of several liquid butadiene polymers functionalized along the chain by alkoxysilyl functions as described above. 3- Non-functional liquid butadiene polymer

[0092] The composition of the invention comprises a non-functional liquid butadiene polymer having a number-average molar mass (Mn) greater than or equal to 1000 g / mol.

[0093] The term "liquid butadiene polymer" according to the invention means a more or less viscous butadiene polymer which is liquid at room temperature (approximately 23°C below atmospheric temperature), that is to say, as a reminder, having the capacity to eventually take the shape of its container.

[0094] The term "butadiene polymer" means a homopolymer or copolymer of butadiene, in other words, a diene polymer selected from the group consisting of polybutadienes, various butadiene copolymers, and mixtures of these polymers. Among butadiene copolymers, particular examples include copolymers of butadiene and a vinylaromatic monomer, preferably styrene.

[0095] Typically, the non-functional liquid butadiene polymer is a low molar mass polybutadiene.

[0096] According to the invention, the non-functional liquid butadiene polymer has a number-average molar mass (Mn) greater than or equal to 1000 g / mol and preferably less than or equal to 50,000 g / mol, more preferably less than or equal to 30,000 g / mol, and more preferably less than or equal to 10,000 g / mol. Thus, according to certain embodiments, the non-functional liquid butadiene polymer has a number-average molar mass (Mn) ranging from 1000 g / mol to 1000 g / mol.

[0097] Preferably, the non-functional liquid butadiene polymer according to the invention also has a Tg greater than -115°C and less than or equal to -60°C, more preferably from -80°C to -110°C.

[0098] According to the invention, the various preferred characteristics above of the non-functional liquid butadiene polymer are combinable with each other.

[0099] The Tg of the non-functional liquid butadiene polymer is measured by DSC according to ASTM D3418 (1999). The macrostructure (Mw, Mn and IP) of the non-functional liquid polymer is determined by size exclusion chromatography (SEC): tetrahydrofuran solvent; temperature 35°C; concentration 1 g / L; flow rate 1 mL / min; solution filtered through a 0.45 µm porosity filter before injection; Moore calibration with polystyrene standards; set of 3 WATERS columns in series ("STYRAGEL" HR4E, HR1 and HR0.5); detection by differential refractometer ("WATERS 2410") and its associated operating software ("WATERS EMPOWER").

[0100] Non-functional low molar mass butadiene polymers useful for the needs of the invention can be found commercially under the name for example "LBR307", "LBR361", "LBR352", "LIR290" marketed by the company KURARAY.

[0101] According to any one of the embodiments of the invention, the proportion of non-functional liquid butadiene polymer is advantageously greater than or equal to 1 pc, preferably within a range of 1 pc to 50 pc, preferably from 2 pc to 30 pc, preferably from 3 pc to 20 pc, preferably still from 5 pc to 15 pc.

[0102] The non-functional liquid butadiene polymer may be a mixture of several non-functional liquid butadiene polymers as described above.

[0103] According to one embodiment of the invention, the sum of the rates of the functional liquid butadiene polymer and the non-functional liquid butadiene polymer is preferably at most 80 parts per cent, preferably still at most equal to 50 parts per cent and preferably still at most 30 parts per cent.

[0104] According to one embodiment of the invention, the proportion of each of the two functional and non-functional liquid butadiene polymers is advantageously at least 2 parts per cent.

[0105] According to one embodiment of the invention, the ratio by mass content of the functional liquid butadiene polymer relative to the non-functional liquid butadiene polymer varies preferably from 4:1 to 1:4, preferably from 1.5:1 to 1:1.5. 4- Reinforcing load

[0106] The composition according to the invention comprises a reinforcing filler. Any type of reinforcing filler known for its ability to reinforce a rubber composition suitable for the manufacture of tires can be used, for example an organic filler such as carbon black, an inorganic reinforcing filler such as silica, alumina, or a blend of these two types of filler. More In particular, the reinforcing filler includes at least one silica, one carbon black, or a mixture of silica and carbon black.

[0107] All carbon blacks are suitable as carbon blacks, particularly those of pneumatic grade. Among the latter, reinforcing carbon blacks of the 100, 200, or 300 series (ASTM grades) are particularly suitable, such as NI 15, N134, N234, N326, N330, N339, N347, N375, or, depending on the intended application, blacks of higher series (e.g., N660, N683, N772). Carbon blacks could, for example, already be incorporated into an isoprene elastomer in the form of a masterbatch (see, for example, applications WO 97 / 36724 or WO 99 / 16600).

[0108] Examples of organic fillers other than carbon blacks include functionalized polyvinyl organic fillers as described in applications WO-A-2006 / 069792, WO-A-2006 / 069793, WO-A-2008 / 003434 and WO-A-2008 / 003435.

[0109] The composition may contain one type of silica or a blend of several silicas. The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenated silica having a BET surface area and a CTAB specific surface area both less than 450 m2 / g, preferably from 30 to 400 m2 / g. Examples of highly dispersible precipitated silicas (HDS) include "Ultrasil 7000" and "Ultrasil 7005" silicas from Degussa, "Zeosil" 1165MP, 1135MP and 1115MP silicas from Solvay, "Hi-Sil EZ150G" silica from PPG, "Zeopol" 8715, 8745 and 8755 silicas from Huber, treated precipitated silicas such as, for example, aluminium-doped silicas described in application EP-A-0735088 or high specific surface area silicas as described in application WO 03 / 16837.

[0110] According to one embodiment of the invention, the reinforcing filler is predominantly an inorganic reinforcing filler (preferably silica), that is to say, it comprises more than 50% (>50%) by weight of an inorganic reinforcing filler such as silica relative to the total weight of the reinforcing filler. Optionally, according to this embodiment, the reinforcing filler also comprises carbon black. According to this option, the carbon black is used at a rate less than or equal to 20%, more preferably less than or equal to 10% (for example, the carbon black content may be in the range of 0.5 to 20%, in particular from 1 to 10%). Within the indicated ranges, the coloring (black pigmenting agent) and anti-UV properties of carbon black are benefited, without otherwise compromising the typical performance provided by the inorganic reinforcing filler.

[0111] In the present exposition, the specific surface area BET is determined by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" (Vol. 60, page 309, February 1938), and more specifically according to a method adapted from the standard NF ISO 5794-1, Annex E of June 2010 [multipoint volumetric method (5 points) - gas: nitrogen - degassing under vacuum: one hour at 160°C - relative pressure range w / in: 0.05 to 0.2].

[0112] For inorganic fillers such as silica for example, the specific surface area values ​​CT AB were determined according to standard NF ISO 5794-1, Annex G of June 2010. The process is based on the adsorption of CTAB (N-hexadecyl-N,N,N-trimethylammonium bromide) on the "external" surface of the reinforcing filler.

[0113] A person skilled in the art will understand that, as an equivalent filler to silica, a reinforcing filler of another nature, in particular organic, could be used, provided that this reinforcing filler is covered with a layer of silica, or has functional sites on its surface, in particular hydroxyl sites, requiring the use of a coupling agent to establish the bond between the filler and the elastomer.

[0114] The physical state in which the reinforcing charge is presented is indifferent, whether in the form of powder, microbeads, granules, balls or any other suitable densified form.

[0115] For the purposes of the invention, the total reinforcing filler content (carbon black and / or inorganic reinforcing filler such as silica) is from 5 to 150 parts per annum, more preferably from 20 to 65 parts per annum. Below 5 parts per annum, the composition may not be sufficiently reinforced, while above 150 parts per annum, the composition may have lower rolling resistance.

[0116] Preferably, silica is used as the major filler. Silica preferably represents more than 50% by mass of the reinforcing filler. In other words, the proportion of silica in the reinforcing filler is greater than 50% by weight of the total weight of the reinforcing filler. More preferably, silica represents more than 85% by mass of the reinforcing filler. According to some preferred embodiments, the silica content varies from 20% to 60%.

[0117] According to the embodiment in which the reinforcing filler comprises silica as the major reinforcing filler, carbon black, when present, is then used, preferably at a rate in the range of 0.1 to 10 pc, more preferably from 0.5 to 10 pc, in particular from 1 to 5 pc.

[0118] To couple the reinforcing inorganic filler to the diene elastomer, a coupling agent (or bonding agent) that is at least bifunctional can be used in a well-known manner to ensure a sufficient connection, of a chemical and / or physical nature, between the inorganic filler (surface of its particles) and the elastomer. diene. Organosilanes or polyorganosiloxanes, at least bifunctional, are used in particular. By "bifunctional," we mean a compound possessing a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the diene elastomer. For example, such a bifunctional compound may comprise a first functional group including a silicon atom, said first functional group being capable of interacting with the hydroxyl groups of an inorganic filler, and a second functional group including a sulfur atom, said second functional group being capable of interacting with the diene elastomer.

[0119] Preferably, the organosilanes are chosen from the group consisting of polysulfide organosilanes (symmetric or asymmetric) such as bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT and marketed under the name "Si69" by Evonik, or bis-(3-triethoxysilylpropyl) disulfide, abbreviated TESPD and marketed under the name "Si75" by Evonik, polyorganosiloxanes, mercaptosilanes, and blocked mercaptosilanes, such as "NXT-Silane" or "NXT-Z45 Silane" marketed by Momentive. Of course, mixtures of these coupling agents could also be used.

[0120] Those skilled in the art will understand that the coupling agent content depends on the amount of reinforcing inorganic filler to be coupled to the elastomer. Typically, the coupling agent content represents 0.5% to 15% by weight relative to the amount of reinforcing inorganic filler, particularly silica.

[0121] The composition according to the invention may optionally also contain coupling activators, inorganic filler recovery agents or more generally processing aids capable, in a known manner, through an improvement in the dispersion of the filler in the rubber matrix and a reduction in the viscosity of the composition, of improving its processing ability in the raw state, these agents being known elsewhere. 5- Crosslinking system

[0122] The crosslinking system can be any type of system known to those skilled in the art in the field of tire rubber compositions. In particular, it can be based on sulfur, and / or peroxide, and / or bismaleimides.

[0123] Preferably, the crosslinking system is sulfur-based; this is referred to as a vulcanization system. The sulfur can be supplied in any form, including molecular sulfur or a sulfur-donating agent. At least one vulcanization accelerator is also preferably present, and optionally, various known vulcanization activators such as zinc oxide, stearic acid, or equivalent compounds may be used. than stearic acid salts and transition metal salts, guanidine derivatives (in particular diphenylguanidine), or known vulcanization retardants.

[0124] Sulfur is used at a preferential rate of between 0.2 and 10 parts per annum, more preferably between 0.3 and 5 parts per annum. The vulcanization accelerator or mixture of accelerators is used at a preferential rate of between 0.5 and 10 parts per annum, more preferably between 0.5 and 5 parts per annum.

[0125] Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur can be used as an accelerator, in particular accelerators of the thiazole type and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. Examples of such accelerators include the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-ter-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds. 6- Possible additives

[0126] The rubber composition according to the invention may optionally also include all or part of the usual additives commonly used in tire elastomer compositions, pigments, plasticizers, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents, reinforcing resins (as described for example in application WO 02 / 10269).

[0127] It goes without saying that the invention relates to the rubber compositions described above both in the so-called "raw" or non-crosslinked state (i.e., before cooking) and in the so-called "cooked" or crosslinked state, or even vulcanized (i.e., after crosslinking or vulcanization). 7- Preparation of the rubber compound

[0128] The composition according to the invention can be manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art: - a first thermomechanical working or mixing phase (the so-called "non-productive" phase), which can be carried out in a single thermomechanical step during which all the necessary constituents are introduced into a suitable mixer such as a standard internal mixer (for example, of the 'Banbury' type), including the elastomeric matrix, the functional and non-functional liquid polybutadiene polymers, the reinforcing filler, and any other miscellaneous additives, with the exception of the crosslinking system. The incorporation of any filler into the elastomer can be carried out in one or more stages by thermomechanical mixing. In the case where the filler is already incorporated, in whole or in part, into the elastomer in the form of a master mix, as described, for example, in applications WO 97 / 36724 or WO 99 / 16600, the master mix is ​​mixed directly, and where applicable, other elastomers or fillers present in the composition that are not in the form of a master mix, as well as any other miscellaneous additives other than the crosslinking system, are incorporated. - a second phase of mechanical work (the so-called "productive" phase), which is carried out in an external mixer such as a roller mixer, after cooling the mixture obtained during the first non-productive phase to a lower temperature, typically below 120°C.

[0129] Such phases are well known to those skilled in the art.

[0130] The final composition thus obtained is then calendered, for example, into a sheet or plate, particularly for laboratory characterization, or extruded (or co-extruded with another rubber composition) into a semi-finished (or profile) rubber product usable in a tire, for example as a tread. These products can then be used for tire manufacturing, according to techniques known to those skilled in the art.

[0131] The composition can be either in the raw state (before crosslinking or vulcanization), or in the cooked state (after crosslinking or vulcanization), can be a semi-finished product that can be used in a tire.

[0132] Crosslinking (or curing), where applicable vulcanization, is carried out in a known manner at a temperature generally between 130°C and 200°C, for a sufficient time which can vary for example between 5 and 90 min depending in particular on the curing temperature, the crosslinking system adopted and the crosslinking kinetics of the composition considered. 8- Pneumatics

[0133] The present invention also relates to a pneumatic or non-pneumatic bandage comprising a rubber composition according to the invention.

[0134] The aforementioned features of the present invention, as well as others, will be better understood upon reading the following description of several examples of embodiments of the invention, given by way of illustration and not limitation. EXAMPLES OF THE INVENTION'S IMPLEMENTATION 1) Tests and measurements

[0135] 1.1- Determination of the microstructure of polymers

[0136] The microstructure of the polymers is determined by ¹H NMR analysis, supplemented by ¹³C NMR analysis when the resolution of the ¹H NMR spectra does not allow for the identification and quantification of all species. The measurements are performed using a BRUKER 500 MHz NMR spectrometer at frequencies of 500.43 MHz for proton observation and 125.83 MHz for carbon observation.

[0137] For insoluble polymers that swell in a solvent, a 4mm z-grad HRMAS probe is used to observe the proton and carbon in proton-decoupled mode. Spectra are acquired at rotation speeds of 4000 Hz to 5000 Hz.

[0138] For measurements on soluble polymers, a liquid NMR probe is used allowing observation of the proton and carbon in proton-decoupled mode.

[0139] The preparation of insoluble samples is carried out in rotors filled with the material being analyzed and a deuterated solvent that allows swelling, generally deuterated chloroform (CDC13). The solvent used must always be deuterated, and its chemical nature can be adapted by those skilled in the art. The quantities of material used are adjusted to obtain spectra with sufficient sensitivity and resolution.

[0140] The soluble samples are dissolved in a deuterated solvent (approximately 25 mg of the polymer in µL), generally deuterated chloroform (CDC13). The solvent or solvent cutting agent used must always be deuterated, and its chemical nature can be adapted by those skilled in the art.

[0141] In both cases (soluble sample or swollen sample):

[0142] For proton NMR, a single 30° pulse sequence is used. The spectral window is adjusted to observe all the resonance lines belonging to the analyzed molecules. The accumulation number is adjusted to obtain a signal-to-noise ratio sufficient for quantifying each motif. The recycling time between each pulse is adapted to obtain a quantitative measurement.

[0143] For carbon NMR, a simple 30° pulse sequence is used with proton decoupling only during acquisition to avoid Nuclear Overhauser Effects (NOE) and maintain quantitative accuracy. The spectral window is adjusted to observe all resonance lines belonging to the analyzed molecules. The accumulation number is set to obtain a signal-to-noise ratio sufficient for quantifying each motif. The recycling time between each pulse is adjusted to obtain a quantitative measurement.

[0144] NMR measurements are carried out at 25°C.

[0145] 1.2- Measurement of dynamic properties

[0146] The dynamic properties G*(25%) and tanômax at 60°C are measured on a viscoelastic analyzer (Metravib VA4000), according to ASTM D 5992-96. The response of a cross-linked composite sample (cylindrical specimen 4 mm thick and 400 mm² cross-section) is recorded under sinusoidal alternating simple shear loading at a frequency of 10 Hz, under the defined temperature conditions of 60°C according to ASTM D 1349-99. A strain amplitude sweep is performed from 0.1 to 100% (forward cycle), then from 100% to 1% (reverse cycle). The results used are the complex dynamic shear modulus G* and the loss factor tan(ô). For the return cycle, we indicate the value of tan(ô) of strain observed at 60°C, noted tanômax, as well as the complex dynamic shear modulus G* at 25% strain, at 60°C.

[0147] The tanômax measurement is a descriptor of hysteresis and therefore an indication of the rolling resistance property of the tire. The value, expressed as a base of 100, is calculated using the following formula: (tanômax value at 60°C of the control / tanômax value at 60°C of the sample) * 100. In this way, a lower value represents a decrease in hysteresis performance (i.e., an increase in hysteresis), while a higher value represents better hysteresis performance (i.e., lower hysteresis).

[0148] The G* (25%) measurement is a stiffness descriptor and therefore an indication of the tire's wear resistance. The value, expressed as a base of 100, is calculated as follows: (G* (25%) value at 60°C of the sample / G* (25%) value at 60°C of the control) * 100. Thus, a lower value represents a decrease in stiffness, while a higher value represents an increase in stiffness.

[0149] 1.3- Measurement of the tearability coefficient (Dz Energy)

[0150] The tear coefficient (expressed in N / m) is the product of the breaking force per unit thickness (expressed in N / mm of thickness) by the elongation at break (expressed in %), measured at 100 °C.

[0151] The tensile strength per unit thickness and the elongation at break in tear resistance are measured on a specimen stretched at 500 mm / min to induce breakage on a tensile testing machine equipped with a system for measuring and acquiring the force and displacement of the moving crosshead. The tensile specimen consists of a parallelepiped-shaped rubber plate, 2.5 mm thick, 145 mm long, and 10 mm wide. Before starting the test, three very fine notches perpendicular to the length of the specimen are made with a razor blade to a depth of 3 mm on one edge of the specimen: one in the middle and the other two on either side of the first, 6 mm apart. The test determines the force (expressed in N per mm of specimen thickness) required to achieve fracture, and the elongation at break (expressed as a percentage) is measured. The test was conducted in air at a temperature of 100°C. High values ​​indicate good cohesion of the rubber composition, even though crack initiation may be present.

[0152] The value in base 100 is calculated according to the operation: (value of the tear coefficient of the sample / value of the tear coefficient of the control) * 100. In this way, a lower value represents a decrease in resistance to tearing, while a higher value represents a better resistance to tearing. 2) Preparation of rubber compositions

[0153] The rubber compositions, the detailed formulation of which is shown in Table 1, were prepared in the following manner:

[0154] The elastomer is introduced into an internal mixer (final filling rate: approximately 70% by volume), the initial tank temperature of which is in the range of 70 to 100°C, for example 80°C. When the temperature reaches 100°C, the liquid butadiene polymer(s), silica, carbon black, and coupling agent are introduced, as well as the various other ingredients, with the exception of sulfur and vulcanization accelerators. A thermomechanical process (non-productive phase) is then carried out in a single step, lasting approximately 3 to 4 minutes in total, until a maximum "drop" temperature of 160°C is reached. The mixture thus obtained is recovered, cooled, and then sulfur and vulcanization accelerators are incorporated on a roller tool at a temperature within a range of 23 to 60°C, for example 40°C, mixing everything (productive phase) for an appropriate time (for example 5 minutes).

[0155] The compositions thus obtained are then calendered either in the form of plates (2 to 3 mm thick) or thin sheets of rubber for the measurement of their physical or mechanical properties. The crosslinking was then carried out at a temperature of 150°C, under pressure. Preparation of the elastomer

[0156] El elastomer is a highly saturated diene elastomer, a copolymer of ethylene and 1,3-butadiene prepared according to the following procedure: In a 70 L reactor containing methylcyclohexane (64 L), ethylene (5600 g), and 1,3-butadiene (2948 g), butylloctylmagnesium (BOMAG) solution is added to the methylcyclohexane and the catalytic system. The Mg / Nd ratio is 6.2. The volume of the catalytic system solution introduced is 840 mL, with an Nd concentration of 0.0065 M. The reaction temperature is controlled at 80°C, and the reaction proceeds as follows: Polymerization begins. The polymerization reaction takes place at a constant pressure of 8.3 bar. The reactor is fed throughout the polymerization process with ethylene and 1,3-butadiene in a molar ratio of 73 / 27. The polymerization reaction is stopped by cooling, degassing the reactor, and adding ethanol. An antioxidant is added to the polymer solution. The copolymer is recovered after steam stripping and drying to a constant mass. The polymerization time is 225 minutes. The weighed mass (6.206 kg) allows the determination of the average catalytic activity of the catalytic system, expressed in kilograms of polymer synthesized per mole of neodymium metal per hour (kg / mol·h). The copolymer has a ML value of 62. The catalytic system is a preformed catalytic system. It is prepared in methylcyclohexane from a metallocene, [Me2Si(Flu)2Nd(q-BH4)2Li(THF)] at 0.0065 mol / L, a co-catalyst, butylmagnesium (BOMAG) with a BOMAG / Nd molar ratio of 2.2, and a preforming monomer, 1,3-butadiene with a 1,3-butadiene / Nd molar ratio of 90. The medium is heated to 80°C for 5 hours. It is prepared according to a method conforming to paragraph II.1 of patent application WO 2017093654 AL

[0157] [Table 1]. Tl T2 T3 Cl Elastomer El (1) 100 100 100 100 Silica (2) 40 40 40 40 Carbon Black (3) 2 2 2 2 Coupling Agent (4) 3.1 3.1 3.1 3.1 LBR-307 (5) 5 10 5 X-12-1267B-ES (6) 5 DPG (7) 1.2 1.2 1.2 1.2 Ozone Wax (8) 1 1 1 1 Antioxidant 6PPD (9) 2 2 2 2 Stearic Acid (10) 2 2 2 2 ZnO(ll) 2.5 2.5 2.5 2.5 Sulfur 1.3 1.3 1.3 1.3 CBS (12) 1 1 1 1 G*25% at 60°C 100 93 90 110 Tanô max at 60°C 100 95 86 104 Energy Dz at 100°C 100 904 1186 894

[0158] (1) Ethylene-1,3-butadiene copolymer containing 74 mol% of unit ethylene, 19% butadiene units in the form of 1,2 and 1,4 motifs and 7 mol% of 1,2-cyclohexanediyl motif, Tg -44°C

[0159] (2) “Zeosil 1165 MP” from Solvay-Rhodia in the form of micropearls

[0160] (3) N234 grade carbon black according to ASTM D-1765, from the company Pooch

[0161] (4) Silane Mercapto - Thiocarboxylate Oligomer ("NXT-Z45") - CAS 922519-17-3 - Momentive company

[0162] (5) “LBR-307”, Kuraray Company, non-functional liquid BR of Tg-95°C and Mn 8000 g / mol

[0163] (6) “X-12-1267B-ES”, Shin-Etsu company, BR functional liquid along the chain of Tg -90°C and Mn 4700 g / mol, of formula

[0164] R* being ethyl.

[0165] (7) Diphenylguanidine “Perkacit DPG” from Flexsys

[0166] (8) Anti-ozone wax “VARAZON 4959” from the company Sasol Wax

[0167] (9) N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine "Santaflex 6PPD" of the Flexsys company

[0168] (70) Stearic acid “Pristerene 4931” from the company Uniqema

[0169] (11 jOxydc of industrial grade Zinc from Umicore Company)

[0170] (12) N-cyclohexyl-2-benzothiazol-sulfenamide “Santicure CBS” of the company Flexsys 3 - Results

[0171] Compositions Tl to T3 are the controls without liquid butadiene polymer (Tl) and with only a non-functional polybutadiene (T2 and T3) at two different concentrations, to evaluate the effect of using combined functional and non-functional liquid polybutadienes, used in composition Cl which is in accordance with the invention.

[0172] The results show, contrary to expectations, that the combined use of a highly saturated diene elastomer and a liquid butadiene polymer functionalized along the chain by pendant alkoxysilyl functions combined with a non-functional liquid butadiene polymer improves the trade-off between the different properties of hysteresis, stiffness and tearability.

[0173] Indeed, the results show that the composition according to the invention (Cl), with an elastomer matrix based on a highly saturated diene elastomer, a liquid polybutadiene functionalized along the chain by alkoxysilyl functions and a non-functional liquid polybutadiene, makes it possible to significantly improve the hysteresis performance (rolling resistance) and the stiffness while maintaining good tear resistance compared with on the one hand a composition (Tl) not comprising any of the liquid polybutadienes and on the other hand compositions (T2 and T3) comprising only a non-functional liquid polybutadiene at two different concentrations.

Claims

Demands

1. Rubber composition based on at least: - an elastomeric matrix comprising predominantly a highly saturated diene elastomer, which highly saturated diene elastomer is a copolymer of ethylene and a 1,3-diene in which the ethylene units represent at least 50% by mole of the monomer units of the copolymer, - a reinforcing filler, - a vulcanizing system - a functional liquid butadiene polymer, which polymer is a liquid butadiene polymer functionalized along the chain by pendant alkoxysilyl groups, optionally totally or partially hydrolyzed, having a number-average molar mass (Mn) greater than or equal to 1000 g / mol, and - a non-functional liquid butadiene polymer, having a number-average molar mass (Mn) greater than or equal to 1000 g / mol.

2. Rubber composition according to claim 1, wherein the ethylene units represent at least 50% and at most 95% by mole of the monomer units of the copolymer, preferably from 65% to 90% by mole of the monomer units of the copolymer.

3. Rubber composition according to any one of the preceding claims, wherein the copolymer of ethylene and a 1,3-diene is a copolymer of ethylene and 1,3-butadiene.

4. Rubber composition according to any one of the preceding claims, wherein the proportion of the highly saturated diene elastomer varies in the range of 60 to 100 pc, preferably 80 to 100 pc, most preferably 90 to 100 pc.

5. Rubber composition according to any one of the preceding claims wherein the functional liquid butadiene polymer is a polybutadiene functionalized along the chain by pendant alkoxysilyl functions, optionally totally or partially hydrolyzed.

6. Rubber composition according to any one of the preceding claims, wherein the liquid polymer of Functional butadiene and non-functional liquid butadiene polymer independently have a rate in the rubber composition in the range of 1 to 50 parts per annum, preferably 2 to 30 parts per annum, and preferably still 5 to 15 parts per annum.

7. Rubber composition according to any one of the preceding claims in which the sum of the rates of functional liquid butadiene polymer and non-functional liquid butadiene polymer is at most 80 pc, preferably at most 50 pc and preferably still at most 30 pc.

8. Rubber composition according to any one of the preceding claims wherein the functional liquid butadiene polymer and the non-functional liquid butadiene polymer independently have a Tg greater than -115°C and less than or equal to -60°C, more preferably from -80°C to -110°C.

9. Rubber composition according to any one of the preceding claims wherein the functional liquid butadiene polymer and the non-functional liquid butadiene polymer independently have a number average molar mass greater than or equal to 1000 g / mol and less than or equal to 50000 g / mol, preferably less than or equal to 30000 g / mol, even more preferably less than or equal to 10000 g / mol.

10. Rubber composition according to any one of the preceding claims wherein the functional liquid butadiene polymer comprises motifs of formula (a) and (c): (a) .. , and (c) .....v. ' ' 1 I çn;; il (R.'OV-Si / \ ' w each R1 independently representing a hydrogen atom or an alkyl radical in Cl-CIO, preferably an alkyl in C1-C4, each R2 independently representing an alkyl radical in CICI 0, preferably an alkyl in C1-C4, m is an integer and is 1, 2 or 3, preferably 3.

11. A rubber composition according to the preceding claim, wherein the functional liquid butadiene polymer does not comprise a vinyl-1,2 motif of formula (b) / Y <b) i ï ] CH \ r /

12. Rubber composition according to any one of the preceding claims wherein the pendant alkoxysilyl functions, optionally totally or partially hydrolyzed, of the chain-functionalized liquid butadiene polymer are trimethoxysilyl or triethoxysilyl functions.

13. Rubber composition according to any one of the preceding claims wherein the reinforcing filler comprises silica as the major reinforcing filler.

14. Rubber composition according to any one of the preceding claims wherein the silica content is in the range of 20 to 60 parts per cent.

15. Pneumatic or non-pneumatic bandage comprising a rubber composition according to any one of the preceding claims.