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, a reinforcing filler, a vulcanizing system and a plasticizing system comprising a hydrocarbon resin having a Tg between 50°C and 120°C, an aliphatic proton content greater than or equal to 95% and a number-average molar mass (Mn) less than or equal to 800 g / mol; the highly saturated diene elastomer being 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.

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 prior art. 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. In WO2020128250A1, the Applicant demonstrated that combining a specific plasticizing system with highly unsaturated copolymers improves the tire's grip performance and even shifts the trade-off between grip and rolling resistance.

[0003] In the field of plasticizers, and in particular plasticizing resins, some of the Applicant's documents mention the use of high Tg resins as plasticizers in SBR-type elastomer-based tire rubber compositions in order to shift the balance between various desired tire performance characteristics, including wear resistance and wet grip. Document WO2013 / 039498 AL is an example.

[0004] Nevertheless, tire manufacturers are always looking for solutions to improve tire performance or shift the balance of their properties. In the area discussed above of tires comprising a highly saturated diene elastomer tread, there is still a need for rubber compositions that give the tire improved rolling resistance properties without compromising other properties such as grip on the road, particularly on wet surfaces. Description of the invention

[0005] 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. Specifically, the Applicant has found a composition of ca rubber which combines the use of a highly saturated diene elastomer with the use of a high Tg resin, and which gives the tire, against all expectations, good rolling resistance properties and an offset compromise of rolling resistance / wet grip properties, notably with improved wet grip properties compared to the combined use of an SBR type diene elastomer and the same high Tg resin.

[0006] Thus, a first object of the invention is a rubber composition based on at least

[0007] - an elastomeric matrix comprising predominantly a highly saturated diene elastomer, - a reinforcing load, - a vulcanization system and - a plasticizing system comprising a high Tg resin.

[0008] 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

[0009] The invention, described in more detail below, relates to at least one of the embodiments listed in the following points:

[0010] 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 load, - a vulcanization system and - a plasticizing system comprising a high Tg (glass transition temperature) hydrocarbon resin, optionally hydrogenated, exhibiting - a Tg between 50°C and 120°C, the Tg being measured according to the standardized method described below, - an aliphatic proton content greater than or equal to 95%, the aliphatic proton content being measured by NMR according to the standardized method described below, and - an average number molar mass (Mn) of less than 800 g / mol, the Mn being measured according to the method described below.

[0011] 2. Rubber composition according to embodiment 1, wherein the ethylene units represent at least 50% and at most 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 65% by mole of the monomer units of the highly saturated diene copolymer, preferably from 65% to 90% by mole of the monomer units of the copolymer.

[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 is statistical.

[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 high Tg hydrocarbon resin content is in the range of 10 to 120 pc, preferably 20 to 110 pc and even more preferably 20 to 80 pc.

[0018] 9. Rubber composition according to any one of the preceding embodiments in which the high Tg hydrocarbon resin has a Tg within a range of 55°C to 110°C, more preferably from 60°C to 100°C.

[0019] 10. Rubber composition according to any one of the preceding embodiments in which the high Tg hydrocarbon resin has a Tg within a range of 60°C to 90°C.

[0020] 11. Rubber composition according to any one of the preceding embodiments in which the high Tg hydrocarbon resin has a number average molar mass greater than or equal to 250 g / mol and less than or equal to 600 g / mol, preferably less than or equal to 500 g / mol.

[0021] 12. Rubber composition according to any one of the preceding embodiments in which the high Tg hydrocarbon resin has a polydispersity index value (PI = Mw / Mn) of at most 2.0, preferably at most 1.8.

[0022] 13. Rubber composition according to any one of the preceding embodiments in which the high Tg hydrocarbon resin has an aliphatic proton content measured by NMR (standard method) of at least 97%.

[0023] 14. Rubber composition according to any one of the preceding embodiments in which the high Tg hydrocarbon resin has a proton ali- phatic measured by NMR (standardized method) of at least 99%.

[0024] 15. Rubber composition according to any one of the preceding embodiments in which the high Tg hydrocarbon resin has an aromatic proton content measured by NMR (standard method) of less than 5%.

[0025] 16. Rubber composition according to the preceding embodiment in which the resin presents an aromatic proton level measured by NMR (standard method) ranging from 0% to 4%, preferably from 0% to 2%.

[0026] 17. Rubber composition according to any one of the preceding embodiments in which the high Tg resin has an ethylenic proton content measured by NMR (standard method) of less than 5%.

[0027] 18. Rubber composition according to any one of the preceding embodiments in which the resin has an ethylenic proton content measured by NMR (standardized method) of less than or equal to 3%.

[0028] 19. Rubber composition according to any one of the preceding embodiments in which the plasticizing system further comprises at least one plasticizing oil or at least one hydrocarbon resin with a Tg of less than 50°C, or at least one plasticizing oil and one hydrocarbon resin with a Tg of less than 50°C.

[0029] 20. Rubber composition according to any one of the preceding embodiments in which the total percentage of plasticizers constituting the plasticizing system is greater than or equal to 10 parts per annum, preferably within a range of 10 to 120 parts per annum.

[0030] 21. Rubber composition according to the preceding embodiment in which the rate The total amount of plasticizers constituting the plasticizing system is in the range of 20 to 120 parts per annum, preferably from 20 to 110 parts per annum.

[0031] 22. 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.

[0032] 23. Rubber composition according to any one of the preceding embodiments in which the reinforcing filler comprises silica as the major reinforcing filler.

[0033] 24. Rubber composition according to any one of the preceding embodiments in which the reinforcing load ratio is within a range of 5 to 200 pc, preferably from 40 to 160 pc.

[0034] 25. Rubber composition according to any one of the preceding embodiments in which the silica content is within a range of 50 to 160 parts per cubic meter.

[0035] 26. Pneumatic or non-pneumatic bandage comprising a composition of ca outchouc according to any of the previous designs.

[0036] 27. Pneumatic or non-pneumatic bandage according to the preceding embodiment comprising a rubber composition according to any one of embodiments 1 to 26 in all or part of its tread. Definitions

[0037] 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.

[0038] 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.

[0039] In the present, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0040] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​from greater than a to less than b (i.e., excluding the bounds a and b), while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​from a to b (i.e., including the strict bounds a and b). In the present case, when an interval of values ​​is designated by the expression "from a to b", the interval represented by the expression "between a and b" is also and preferably designated.

[0041] 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.

[0042] 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 to say, it is the one that represents the greatest 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 charge is the one representing the greatest mass among the charges in the composition. By way of example, in a system comprising a single elastomer, this elastomer is the major compound for the purposes of this invention; and in a system comprising two elastomers, the major elastomer represents more than half the mass of the elastomers. Conversely, a "minor" compound is a compound that does not represent the fraction the largest mass proportion among compounds of the same type. Preferably, by major, we mean a mass proportion of more than 50%; when the compound represents 100% by mass, it is also described as "major".

[0043] 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 in use, 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, plasticizers, fillers, etc.

[0044] 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 1-1 Elastomer matrix

[0045] By "elastomer matrix", we mean the set of elastomers in the composition.

[0046] According to the invention, the elastomeric matrix predominantly comprises at least one highly saturated diene elastomer, namely a copolymer containing ethylene units and 1,3-diene units (hereinafter referred to as "the copolymer").

[0047] The highly saturated diene elastomer useful for the purposes of the invention is a copolymer, preferably a statistical copolymer. A "statistical copolymer" is understood to be a copolymer in which the sequential distribution of the monomer units obeys a known statistical law.

[0048] The highly saturated diene elastomer useful for the purposes of the invention is a copolymer comprising ethylene units resulting from the polymerization of ethylene. The term "ethylene unit" refers, as is known, to the motif -(CH2-CH2)- resulting from the insertion of ethylene into the elastomer chain. The highly saturated diene elastomer is rich in ethylene units, since 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, and more preferably at most 90% by mole. Thus, according to one embodiment, ethylene units represent from 50% to 95% by mole of the monomer units of the highly saturated diene copolymer.

[0049] Preferably, the highly saturated diene elastomer comprises at least 65% molar percentage of ethylene units. In other words, ethylene units preferably represent at least 65% by mole of all the monomer units of the highly saturated diene elastomer. More preferably, the highly saturated diene elastomer comprises 65% to 90% molar percentage of ethylene units, the molar percentage being calculated on the basis of all the monomer units of the highly saturated diene elastomer.

[0050] 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.

[0051] The 1,3-diene units are those, for example, of a 1,3-diene having 4 to 24 carbon atoms.

[0052] Suitable as 1,3-diene include butadiene, isoprene, 2,3-di(alkyl in C1 to C5)-1,3-butadiene such as, for example, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene or 2-methyl-3-isopropyl-1,3-butadiene, aryl-1,3-butadiene such as phenyl-1,3-butadiene, 1,3-pentadiene. A suitable 1,3-diene is also a 1,3-diene of the formula CH2=CR-CH=CH2, 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 (Ci5H24), like [3-farnesene etc....

[0053] 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.

[0054] 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, preferably statistically.

[0055] 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.

[0056] 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, and according to known synthetic methods, in particular 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.

[0057] 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.

[0058] According to the invention, the content of the 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). Even more preferably, the content of the highly saturated diene elastomer in the rubber composition varies in the range of 60 to 100 wt, preferably 80 to 100 wt. Most preferably, it varies in the range of 90 to 100 wt.

[0059] 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. 1-2 Specific plasticizer

[0060] High Tg resin

[0061] The composition of the invention comprises at least one hydrocarbon resin having a Tg between 50 °C and 120 °C, referred to as "high Tg", and an average number molar mass (Mn) less than or equal to 800 g / mol.

[0062] Preferably, the high Tg hydrocarbon plasticizing resin has at least one of the following characteristics:

[0063] - a Tg within a range of 55°C to 110°C, more preferably from 60°C to 100°C, and even more preferably from 60°C to 90°C;

[0064] - an average number-average molar mass (Mn) greater than or equal to 150 g / mol, of preferably greater than or equal to 250 g / mol and less than or equal to 600 g / mol, plus preferably greater than or equal to 250 g / mol and less than or equal to 500 g / mol;

[0065] - a polydispersity index (PI = Mw / Mn) value of at most 3.0, preferably at most 2.0, preferably at most 1.8.

[0066] More preferably, this high Tg hydrocarbon plasticizing resin has all the above preferred characteristics.

[0067] The Tg is measured according to ASTM D3418 (1999). The macrostructure (Mw, Mn and IP) of the hydrocarbon resin is determined by size exclusion chromatography (SEC): tetrahydrofuran solvent; temperature 35°C; concentration 1 g / l; flow rate 1 ml / min; solution filtered on 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").

[0068] The hydrocarbon resins according to the invention may be aliphatic or of the mixed aliphatic / aromatic type, that is to say, the hydrocarbon resins according to the invention comprise aliphatic constitutional units or aliphatic constitutional units and aromatic constitutional units. They may be natural or synthetic, petroleum-based or not.

[0069] The hydrocarbon resins according to the invention may be obtained from the polymerization of one or more monomers, including aromatic and aliphatic monomers. The hydrocarbon resins may have undergone partial or total hydrogenation following polymerization.

[0070] According to one embodiment, the high Tg hydrocarbon plasticizing resin of the invention is selected from the group consisting of cyclopentadiene (CPD) or dicyclopentadiene (DCPD) homopolymer or copolymer resins, terpene homopolymer or copolymer resins, terpene-phenol homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins, styrene homopolymer or copolymer resins, C9-cut homopolymer or copolymer resins (or more generally, C8 to C10 cuts), and mixtures of these resins. The term "terpene" here encompasses, in a well-known manner, the alpha-pinene, beta-pinene, and limonene monomers.

[0071] According to one embodiment of the invention, the high Tg hydrocarbon resin has an aliphatic proton content of at least 97%. According to a particular embodiment of the invention, the high Tg hydrocarbon resin has an aliphatic proton content of at least 99%.

[0072] According to any one of the embodiments, the hydrocarbon resin useful for the purposes of the invention preferably has an aromatic proton content of less than 5%, preferably within a range of 0% to 4%, of preference of 0% to 2%.

[0073] According to any one of the embodiments, the hydrocarbon resin useful for the needs of the invention preferably has an ethylenic proton content of less than 5%, preferably within a range of 0% to 3%.

[0074] The aliphatic proton content, the aromatic proton content (%HA), and the ethylenic proton content (%HE) are measured by 1H NMR. This determination is performed with respect to all detected signals. Thus, the results obtained are expressed as a percentage of peak area.

[0075] The samples are solubilized in deuterated chloroform (CDC13) at a ratio of approximately 10 mg of resin in approximately 1 mL of solvent. Spectra are acquired on a Bruker Avance 500 MHz spectrometer equipped with a Bruker 5 mm z-grad BBO broadband probe. The 1H NMR experiment uses a single 30° pulse sequence and a 5-second repetition delay between each acquisition. 64 accumulations are performed at room temperature. The chemical shifts are calibrated with respect to the protonated impurity of the deuterated chloroform; 0 ppm 1H at 7.20 ppm. The 1H NMR signals of aromatic protons are located between 8.5 ppm and 6.2 ppm. Ethylene protons, on the other hand, generate signals between 6.2 ppm and 4.5 ppm. Finally, the signals corresponding to aliphatic protons are located between 4.5 ppm and 0.1 ppm. The areas of each proton category are expressed as the sum of these areas to give a percentage distribution of the area of ​​each proton category.

[0076] Resins usable within the framework of the invention are commercially available, for example sold by Kolon Industries under the name "SU-640" (Tg = 83°C, 100% aliphatic, Mn 398g / mol).

[0077] According to any one of the embodiments of the invention, the percentage of high Tg hydrocarbon plasticizing resin is advantageously greater than or equal to 10 pc, preferably within a range of 10 pc to 120 pc, preferably from 20 to 120 pc, preferably again from 20 pc to 110 pc or even from 20 to 80 pc.

[0078] The high Tg hydrocarbon plasticizing resin can be a mixture of several high Tg hydrocarbon plasticizing resins as described above.

[0079] The plasticizing system according to the invention may comprise, in addition to the high Tg hydrocarbon plasticizing resin, at least one plasticizing oil or at least one hydrocarbon resin with a Tg below 50°C, or at least one plasticizing oil and one hydrocarbon resin with a Tg below 50°C. These plasticizers are well known to those skilled in the art and are commercially available.

[0080] The total proportion of plasticizers (high Tg hydrocarbon plasticizing resin, plasticizing oil, hydrocarbon resin with a Tg below 50°C) constituting the plasticizing system is greater than or equal to 10 parts per cent, preferably within a range of 10 to 120 parts per cent. According to certain embodiments, the total proportion of plasticizers constituting the plasticizing system is included in a range of 20 to 120 pieces, preferably included in a range of 20 to 110 pieces. 1-3 Reinforcing Load

[0081] 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 tire manufacturing 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 particularly, the reinforcing filler comprises at least silica, carbon black, or a mixture of silica and carbon black.

[0082] 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).

[0083] 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.

[0084] 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.

[0085] The composition according to the invention may optionally also contain coupling agents, coupling activators, inorganic filler coating agents, or more generally processing aids capable, in a known manner, of improving the dispersion of the filler in the rubber matrix and lowering the viscosity of the composition, of improving its The ability to be implemented in the raw state, these agents being for example hydrolyzable silanes such as alkylalkoxysilanes, polyols, fatty acids, polyethers, primary, secondary or tertiary amines, hydroxylated or hydrolyzable polyorganosiloxanes. In particular, polysulfide silanes, described as "symmetric" or "asymmetric" depending on their specific structure, as described for example in applications WO03 / 002648 (or US 2005 / 016651) and WO03 / 002649 (or US 2005 / 016650), can be used.

[0086] In the rubber composition according to the invention, the coupling agent content is preferably between 1 and 20 parts per cent. Typically, the coupling agent content represents 0.5% to 15% by weight relative to the amount of reinforcing inorganic filler.

[0087] A person skilled in the art will understand that, as an equivalent filler to the silica described in this paragraph, 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 hydroxylated sites, requiring the use of a coupling agent to establish the bond between the filler and the elastomer.

[0088] 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.

[0089] 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 200 parts per annum, more preferably from 40 to 160 parts per annum. Below 5 parts per annum, the composition may not be sufficiently reinforced, while above 200 parts per annum, the composition may have lower rolling resistance.

[0090] Preferably, silica is used as the major filler, preferably in a proportion of 50 to 160 parts per cent, more preferably 60 to 150 parts per cent, and optionally, carbon black. Carbon black, when present, is then used in a minor proportion, preferably in a proportion of 0.1 to 10 parts per cent, more preferably 0.5 to 10 parts per cent, in particular 1 to 5 parts per cent. 1-4 Crosslinking System

[0091] 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.

[0092] 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, from Optionally, and also preferentially, various known vulcanization activators such as zinc oxide, stearic acid or equivalent compounds such as stearic acid salts and transition metal salts, guanidine derivatives (in particular diphenylguanidine), or even known vulcanization retardants can be used.

[0093] 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 accelerator mixture 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.

[0094] 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. 1-5 Possible Additives

[0095] 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, 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).

[0096] 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).

[0097] 1-6 Preparation of the rubber composition

[0098] 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, including the elastomeric matrix, the reinforcing filler, and any other components, are introduced into a suitable mixer such as a standard internal mixer (for example, of the 'Banbury' type). Various additives, with the exception of the crosslinking system, may be used. The incorporation of any filler into the elastomer may be carried out in one or more stages by thermomechanical mixing. If the filler is already fully or partially incorporated into the elastomer as a master mix, as described, for example, in applications WO 97 / 36724 or WO 99 / 16600, the master mix is ​​mixed directly, and, if necessary, any other elastomers or fillers present in the composition that are not in master mix form, as well as any other miscellaneous additives other than the crosslinking system, are incorporated. The non-productive phase may be carried out at high temperature, up to a maximum temperature between 110°C and 200°C, preferably between 130°C and 185°C, for a duration generally between 2 and 10 minutes.

[0099] - 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, for example between 40°C and 100°C. The crosslinking system is then incorporated, and the whole is then mixed for a few minutes, for example between 5 and 15 min.

[0100] Such phases are well known to those skilled in the art.

[0101] 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 the manufacture of tires, according to techniques known to those skilled in the art.

[0102] 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.

[0103] 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. 1-7 Pneumatic

[0104] The present invention also relates to a pneumatic or non-pneumatic bandage comprising a rubber composition according to the invention.

[0105] Preferably, the composition according to the invention is present at least in the tread of the pneumatic or non-pneumatic tire according to the invention.

[0106] The aforementioned features of the present invention, as well as others, will be better understood by reading the following description of several examples of implementation of the invention, given for illustrative and non-limiting purposes. II. EXAMPLES OF THE IMPLEMENTATION OF THE INVENTION II.1 Tests and measurements:

[0107] IL 1-1 Determination of the microstructure of elastomers:

[0108] The microstructure of the elastomers 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.

[0109] For insoluble elastomers 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.

[0110] For measurements on soluble elastomers, a liquid NMR probe is used allowing observation of the proton and carbon in proton-decoupled mode.

[0111] 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.

[0112] The soluble samples are dissolved in a deuterated solvent (approximately 25 mg of elastomer 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.

[0113] In both cases (soluble sample or swollen sample):

[0114] 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.

[0115] For carbon NMR, a simple 30° pulse sequence is used with proton decoupling only during acquisition to avoid Nuclear Overhauser (NOE) effects and maintain quantitative accuracy. The spectral window is adjusted to observe all resonance lines belonging to the analyzed molecules. The accumulation number is adjusted to obtain a sufficient signal-to-noise ratio. for the quantification of each pattern. The recycling time between each pulse is adjusted to obtain a quantitative measurement.

[0116] NMR measurements are carried out at 25°C. II. 1-2 Determination of Mooney viscosity

[0117] The Mooney viscosity ML(l+4) at 100 °C is measured according to ASTM D 1646.

[0118] An oscillating consistometer is used as described in ASTM D 1646. The Mooney plasticity measurement is performed according to the following principle: the raw composition (i.e., before firing) is molded in a cylindrical chamber heated to 100 °C. After one minute of preheating, the rotor rotates inside the test specimen at 2 revolutions per minute, and the torque required to maintain this rotation after 4 minutes of rotation is measured. The Mooney plasticity ML(l+4) is expressed in "Mooney units" (MU, with 1 MU = 0.83 Nm). II. 1-3 Measurement of dynamic properties: Dynamic properties

[0119] The dynamic properties tan(φ)max are measured on a viscoanalyzer (Metravib V A4000), according to ASTM D5992-96. The response of a vulcanized composition sample (cylindrical specimen 2 mm thick and 79 mm² cross-section) subjected to sinusoidal loading in alternating simple shear at a frequency of 10 Hz is recorded. A temperature sweep is performed from -80°C to +100°C with a ramp of +1.5°C / min, under a stress of 0.7 MPa.

[0120] Temperature hysteresis is determined by taking the integral of the loss angle (tan(θ)) in the interval [-30°C; 0°C] over a temperature sweep at an imposed stress of 0.7 MPa. This measurement is a descriptor of the tire's grip on the wet or damp surface. The value based on 100 is calculated using the following formula: (value of the integral of the loss angle in the interval [-30°C ; 0°C] of the sample / value of the integral of the loss angle in the interval [-30°C ; 0°C] of the control) * 100. In this way, a lower value represents a decrease in wet grip performance (i.e. a lower value of the integral of the loss angle in the interval [-30°C ; 0°C]) while a higher value represents better wet grip performance (i.e. a higher value of the integral of the loss angle in the interval [-30°C ; 0°C]).

[0121] Strain hysteresis is determined by taking the maximum value of the loss angle on a return scan from a strain scan at 23°C ranging from 0.01% to 100% peak-to-peak strain. This measurement is a descriptor of hysteresis and therefore an indication of the tire's rolling resistance property. The value, based on 100, is calculated using the following formula: (value of tan(φ)max at 23°C of the control / value of tan(φ)max at 23°C of the sample) * 100. In this way, a value A lower value represents decreased performance in hysteresis (i.e., increased hysteresis), while a higher value represents better performance in hysteresis (i.e., weaker hysteresis). II.2 Preparation of rubber compositions:

[0122] The rubber compositions, the detailed formulation of which is shown in Table 1, were prepared in the following manner:

[0123] The elastomer is introduced into an internal mixer (final filling rate: approximately 70% by volume), the initial tank temperature of which is approximately 90°C. When the temperature reaches 100°C, half of the silica and resin, as well as the carbon black and coupling agent, are introduced. The other half of the silica and resin, the oil, and the various other ingredients, with the exception of sulfur and vulcanization accelerators, are introduced at 120°C. 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 collected, cooled, and then sulfur and vulcanization accelerators are incorporated on a mixer (homo-finisher) at 30 °C, mixing everything (productive phase) for an appropriate time (for example, about ten minutes).

[0124] The compositions thus obtained are then calendered either in the form of plates (thickness 2 to 3mm) or thin sheets of rubber for the measurement of their physical or mechanical properties, or extruded in the form of a tread for tire. Preparation of the elastomer

[0125] The elastomer (EBR) is prepared according to the following procedure:

[0126] The EBR elastomer is prepared in the presence of a catalytic system based on a metallocene [Me2Si(Flu)2Nd(q-BH4)2Li(THF)] and a co-catalyst, butyloctyl-magnesium, according to the following procedure:

[0127] In a reactor containing methylcyclohexane, the co-catalyst (0.36 mmol / L) is added, followed by the metallocene (0.07 mmol / L). The alkylation time is 10 minutes, and the reaction temperature is 20 °C. Ethylene and 1,3-butadiene are then added continuously in molar amounts of 80% and 20%, respectively, to the reactor. Polymerization is carried out at 80 °C under a pressure of 8 bar. 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 by drying in a vacuum oven to a constant mass (Method in accordance with that of patent application WO2020 / 212184 A1).

[0128] [Tables] Cl C2 C3 C4 C5 C6 Elastomer (1) 100 100 100 Elastomer (2) 100 100 100 Carbon Black (3) 2 2 2 2 2 2 Silica (4) 96 96 96 96 96 96 Silane (5) 8 8 8 8 8 8 Plasticizer (6) 15 15 15 15 15 15 Plasticizer (7) 30 30 Plasticizer (8) 30 30 Plasticizer (9) 30 30 DPG (10) 2.1 2.1 2.1 2.1 2.1 2.1 Ozone Wax (11) 2.6 2.6 2.6 2.6 2.6 2.6 6PPD (12) 3.8 3.8 3.8 3.8 3.8 3.8 TMQ(13) 1.6 1.6 1.6 1.6 1.6 1.6 Stearic acid (14) 3 3 3 3 3 3 ZnO (15) 1 1 1 1 1 1 CBS (16) 2.3 2.3 2.3 2.3 2.3 2.3 Sulfur 0.9 0.9 0.9 0.9 0.9 0.9

[0129] 1. E / ostoraer E8R .• ethylene cough of 77.1% 010 / 0 / / ¾ dutodene cough of 22.9% moi of which lOSèmof of moft / s 1,2-, 5.3%mo / de motÿs .1,4- and 7.6%mal cycles, with «n Mooney ML / 1-+4 / at 1®°C of &5et ««e Tg -40 "C 2. Elastamer SBR; 27% by weight styrene and 24% by weight relative to the diene portion of 1,2-butadiene motifs, with a Mooney 0 100 aC of 54 and a Tg = -4S*C 3. Wofr^SFM #234 of your company CABOT 4. "Zeosil 1165 'MPM of Soh / ày-fl / iod / à sous fpmie de microperles 5. Silane / / qu / de triethoxysii^ fTESPT / « 8169 » of your company Evonik 6. Triocty! phosphate ftri-2-ethythexyi phosphate) «Disflamoil TOT» from the company LanxessfTg = -110'Q 7. Exxon ktabU "Squeeze 5600" resin (Tg = SS^C, 90% atypical, Mn 50Gg / mo#) 8. : Resin « R2495 s du^t / rn / sseur P1Ü0VA (Tg = 33*C, 96% aliphatic, Mn 8É9g / / no / J 9. Res / he “SU-64&” from Kolon Industries (Tg = dJT, 100% ailphatic, Mn 398g / mal) 10. Diphenylgugnldine “Perkacit DPG” from Flexsys 11. Anti-osorie wax “VARAZON 4959 & from your company Sosp / M / ox 12. Saoto / tex 6PPD from FLEXSYS company 13, 2,2,4-trin}ethyl-l,2-dlhydroquihidlne (TMQ) from the company Lonxess 14. Stearic acid “Pnsterene 4931 -” from the company tfrdqema 15. Industrial grade zinc oxide from the company l / ra / core 16, ,JV-cyc / o / jexy / -2r&enzothlacoi-su / fénamfde « Santacure CSS » of the company Elexsys

[0130] The characteristics of the resins, ingredients 7 to 9 are shown in Table 2.

[0131] [Tables2] Name Tg Mn IP % Aliphatic % Aromatic % Ethylene “Escorez 5600” resin (7) 55°C 500g / mo 1 1.6 90% 10% - “R2495” resin (8) 93°C 869g / mo 1 1.32 96% 1% 3% “SU-640” resin (9) 83°C 398g / mo 1 1.65 100% - - n.3 Results:

[0132] The results are shown in Table 3.

[0133] [Tables3] Cl C2 C3 C4 C5 C6 Summary of elastomeric components and resins EBR (la) 100 100 100 SBR (1b) 100 100 100 Resin (7) 30 30 Resin (8) 30 30 Resin (9) 30 30 Results tan(φ)max at 23°C 100 91 105 100 89 110 Int. tan(φ) [-30°C ; 0°C] 100 93 87 100 106 109

[0134] Composition Cl is the control for compositions C2 and C3 based on SBR, composition C4 is the control for compositions C5 and C6 based on EBR.

[0135] The results show that the composition according to the invention, with an elastomer matrix based on an EBR and a high Tg resin with a high aliphatic proton content, makes it possible, against all expectations, to greatly improve hysteresis performance (rolling resistance) while improving adhesion on wet ground.

[0136] The adhesion performance on wet ground is degraded for compositions whose elastomer matrix is ​​based on SBR with tg = -48°C associated with a high Tg resin with a high aliphatic proton content (comparison of C3 with respect to Cl and C2).

[0137] The results also show that when the high Tg resin does not have all the required characteristics, particularly in terms of Mn (Resin (8)), when the elastomer matrix is ​​based on an EBR, the improvement in hysteresis performance is less and the wet surface adhesion / hysteresis compromise is degraded compared to a composition comprising a high Tg resin according to the invention and an elastomer matrix based on an EBR (comparison of C5 compared to C4).

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 and - a plasticizing system comprising a high Tg (glass transition temperature) hydrocarbon resin, optionally hydrogenated, having - a Tg between 50°C and 120°C, measured according to ASTM D3418 (1999), - an aliphatic proton content greater than or equal to 95%, measured by NMR according to the standardized method described therein, and - a number-average molar mass (Mn) less than or equal to 800 g / mol, measured according to the method described therein.

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%.

3. Rubber composition according to any one of the preceding claims, wherein the 1,3-diene is 1,3-butadiene, isoprene, myrcene, [3-farnesene, or a mixture of myrcene and [3-famesene, preferably 1,3-butadiene or isoprene.

4. 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.

5. 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.

6. Rubber composition according to any one of the preceding claims wherein the high Tg hydrocarbon resin content is in the range of 10 to 120 pc, preferably 20 to 110 pc.

7. Rubber composition according to any one of the claims previous in which the high Tg hydrocarbon resin has a Tg within a range of 55°C to 110°C, more preferably from 60°C to 100°C.

8. Rubber composition according to any one of the preceding claims wherein the high Tg hydrocarbon resin has a number-average molar mass greater than or equal to 250 g / mol and less than or equal to 600 g / mol.

9. Rubber composition according to any one of the preceding claims wherein the high Tg hydrocarbon resin has a polydispersity index value (PI = Mw / Mn) of at most 2.0, preferably at most 1.

8.

10. Rubber composition according to any one of the preceding claims wherein the high Tg hydrocarbon resin has an aliphatic proton content measured by NMR (standard method) of at least 97%.

11. Rubber composition according to any one of the preceding claims wherein the high Tg hydrocarbon resin has an aliphatic proton content measured by NMR (standard method) of at least 99%.

12. Rubber composition according to any one of the preceding claims wherein the high Tg hydrocarbon resin has an aromatic proton content of less than 5%.

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 50 to 160 parts per cent.

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