Grafted polymer carrying pendant imidazole functional groups

Abstract

The present invention relates to a process for the preparation of a modified polymer comprising pendant imidazole functional groups, said process comprising a step of grafting, onto a starting polymer comprising at least one unsaturation, a compound comprising an epoxide group, and a step of reacting the grafted polymer obtained at the end of the preceding step with a compound comprising an imidazol group.

Description

[0001] DESCRIPTION

[0002] POLYMER GRAFT CARRYING FUNCTIONAL IMIDAZOLS PENDANT GROUPS

[0003] FIELD OF INVENTION

[0004] The field of the invention is that of polymers, in particular that of functional elastomers, especially dienic elastomers, comprising nitrogen and hydroxyl heterocycle functions or epoxy functions, nitrogen and hydroxyl heterocycles, their manufacturing processes and their uses in compositions, in particular in rubber compositions intended especially for the manufacture of pneumatic or non-pneumatic tires.

[0005] STATE OF THE ART

[0006] Ideally, a rubber compound intended for use in pneumatic or non-pneumatic tires must meet a large number of technical requirements. One of these requirements concerns its cohesion, which is generally achieved through a good level of reinforcement. It is known that the reinforcement of a rubber compound can be improved by introducing reinforcing fillers, coupling agents to bond the rubber to the reinforcing filler, or functional elastomers.

[0007] Another technical requirement that these rubber compositions must meet is to have good limiting properties so that the pneumatic or non-pneumatic tire exhibits good endurance, and therefore the longest possible lifespan.

[0008] However, it is known that improving one property of a rubber composition comes at the expense of another.

[0009] For example, experts know that increasing the reinforcement of a rubber compound makes it more rigid. This increased rigidity results in a decrease in its extensibility. If extensibility decreases, the tire will be less resistant to physical stress, thus exhibiting reduced durability and ultimately a shorter lifespan. Given the dwindling cost of raw materials and energy, it is becoming increasingly important for manufacturers to offer pneumatic and non-pneumatic tires with a certain longevity, and therefore good durability.

[0010] It is therefore a permanent objective of designers of rubber compositions to ensure that the improvement of certain properties does not come at the expense of others, in particular that obtaining a rubber composition with good cohesion also exhibits good extension properties.

[0011] It is therefore desirable to have polymers that promote good reinforcement of the rubber composition to which they are added without an excessive decrease in mechanical properties such as tensile strength and elongation at break.

[0012] We know from document W02015059269A1 and W02020249631A1 of elastomers grafted by a 1,3-dipolar compound of formula QAB in which the group Q comprises a dipole containing at least one nitrogen atom, A is a divalent group which may be aromatic, heteroaromatic or not and B an imidazole function.

[0013] In the past, it has also been discovered that the introduction of diene polymers, particularly elastomers, bearing at least one epoxide pendant group via the modification of a polymer having an unsaturation by a 1,3-dipolar compound bearing an epoxide group (W02019102126A1, W02019102128A1 and US20120046418A1) makes it possible to access rubber compositions having reinforcement properties maintained or improved compared to compositions not comprising functionalized polymers (W02019102132A1, and W02022 / 003278A1).

[0014] There is therefore a constant need to provide new processes for the preparation of functional polymers, in particular elastomers, especially dienic ones, allowing access to compositions with a good compromise of properties which are reinforcement as well as mechanical properties such as elongation at break and tensile strength at break.

[0015] DESCRIPTION OF THE INVENTION

[0016] The applicant has thus developed a new process for the preparation of a modified polymer (III) comprising the following steps:

[0017] (a) a grafting step, on a starting polymer comprising at least one unsaturation, of a compound of formula (I) comprising an epoxide group, said grafting step comprising a step (a1) of mixing said polymer and said compound of formula (I) as follows: in which:

[0018] Q represents a dipole comprising at least one nitrogen atom; A represents a C0-CM arenediyl ring, possibly substituted by one or more identical or different, aliphatic hydrocarbon chains, preferably saturated, linear or branched, possibly substituted or interrupted by one or more heteroatoms;

[0019] E represents a divalent hydrocarbon group in C1-C20 possibly comprising one or more heteroatoms;

[0020] Xi, X?, X3, identical or different, represent a hydrogen atom, an alkyl in CI-CO or an aryl in CO-CM;

[0021] (b) a reaction step between the grafted polymer obtained at the end of step (a) and a compound of formula (II) to obtain the modified polymer (III), said reaction step comprising a mixing step (b1) of said grafted polymer and said compound of formula (II) as follows: in which Z, Y, R and R', identical or different, represent a hydrogen atom, a CI-CO alkyl, a (CI-CO)alkyl-aryl in C or a CO-CM aryl, possibly comprising one or more heteroatoms, Y and Z being able to form together a ring, in particular an aromatic ring, with the carbon atoms of the imidazole ring to which they are attached, the product obtained at the end of said process being a composition comprising the modified polymer (III), or the modified polymer (III) itself.

[0022] Preferably, the starting polymer is an elastomer, more preferably a diene elastomer.

[0023] Preferably, the compound of formula (I) is chosen from the compound of formula (Via) and the compound of formula (Vlb) of the following formulas:

[0024] in which:

[0025] - a grouping chosen from R7 to Ru of formula (la) and a grouping chosen from R7 to R13 of formula (Ib) designates the group according to formula (V), such that: E is an -O-R14- group with R14 a linear or C1-C10 branched alkyl group; Xi, X? and X3 are hydrogen atoms

[0026] - the four other groups from R7 to Ru of formula (la) and the six other groups from R7 to R13 of formula (Ib) represent independently of each other, a hydrogen atom or a hydrocarbon chain, aliphatic, preferably saturated, linear or branched, possibly substituted or interrupted by one or more heteroatoms.

[0027] Preferably, compound (II) is chosen from the group consisting of 1-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 1-benzyl-2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1,2-dimethylimidazole and mixtures of these compounds.

[0028] Preferably, the molar ratio of the compound of formula (I) relative to the starting polymer is from 0.1% to 0.6%, more preferably from 0.2% to 0.5%, even more preferably from 0.2% to 0.4%.

[0029] Preferably, the ratio of the molar content of compound of formula (II) to the molar content of compound of formula (I) is from 20% to 125%, preferably from 40% to 120%, even more preferably from 50% to 120%. Preferably, steps a1) and b1) are carried out in bulk, and step a1) is carried out at a temperature below 40°C, and is followed by a heat treatment step a2) under pressure or in an oven at temperatures from 40°C to 200°C, or step a) consists of step a1) carried out at a temperature above 60°C; and step b1) is carried out at a temperature below 40°C, and step b1) is followed by a step b2) of heat treatment under press or in oven at temperatures ranging from 40°C to 200°C, preferably from 80°C to 200°C, or step b) consists of step b1) carried out at a temperature above 60°C.

[0030] Preferably, steps a1) and b1) are carried out in bulk, and step a) consists of step a1) carried out at a temperature below 40°C, and step b1) is carried out at a temperature below 40°C, and it is followed by a step b2) of heat treatment under press or in oven at temperatures ranging from 40°C to 200°C, preferably from 80°C to 200°C, or step b1) is carried out at a temperature above 60°C.

[0031] Another object of the invention relates to a composition that can be obtained according to the process as described above, comprising a modified polymer (III), of formula (Ilia) if R'=H or (I II b) if R' is different from H: * representing the bond to the starting polymer, said bond being made up of the E, A groups, and the covalent bond resulting from the cycloaddition [3+2] of the Q group of the compound of formula (I) on at least one unsaturation of said polymer.

[0032] Another object of the invention relates to a modified polymer (III), of formula (Hla) if R'=H or (Illb) if R' is different from H:

[0033] * representing the bond to the starting polymer, said bond being made up of the E, A groups, and the covalent bond resulting from the cycloaddition [3+2] of the Q group of the compound of formula (I) on at least one unsaturation of said polymer, said polymer being capable of being obtained according to the process as described above.

[0034] The invention also relates to a rubber composition based on at least one reinforcing filler, a crosslinking system and at least:

[0035] - a composition as described above or obtained according to the process as described above;

[0036] - and / or a modified polymer (III) as described above or obtained by the process as described above.

[0037] Another object of the invention relates to a semi-finished article for pneumatic or non-pneumatic tires, said semi-finished article comprising a rubber composition as described above. Another object of the invention relates to a pneumatic or non-pneumatic tire comprising at least one rubber composition as described above, or alternatively, a semi-finished article as described above.

[0038] Other aspects of the invention are as described below.

[0039] DETAILED DESCRIPTION OF THE INVENTION

[0040] Definitions

[0041] In this application, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0042] 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, 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, including the strict bounds a and b).

[0043] The invention therefore relates to a process for the preparation of a modified polymer (III) comprising the following steps:

[0044] (a) a grafting step, on a starting polymer comprising at least one unsaturation, of a compound of formula (I) comprising an epoxide group, said grafting step comprising a step (a1) of mixing said polymer and said compound of formula (I) as follows: in which:

[0045] Q represents a dipole comprising at least one nitrogen atom;

[0046] A represents an arendiyl ring in C0-CM, possibly substituted by one or more hydrocarbon chains, identical or different, aliphatic, preferably saturated, linear or branched, possibly substituted or interrupted by one or more heteroatoms;

[0047] E represents a divalent hydrocarbon group in C1-C20 possibly comprising one or more heteroatoms; Xi, X?, X3 identical or different, represent a hydrogen atom, an alkyl in CI-CO or an aryl in CO-CM;

[0048] (b) a reaction step between the grafted polymer obtained at the end of step (a) and a compound of formula (II) to obtain the modified polymer (III), said reaction step comprising a mixing step (b1) of said grafted polymer and said compound of formula (II) as follows: in which Z, Y, R and R', identical or different, represent a hydrogen atom, an alkyl in CI-CO, a (CI-CO)alkyl-aryl in CO OR an aryl in CO-CM, possibly comprising one or more heteroatoms, Y and Z being able to form together a ring, in particular an aromatic one, with the carbon atoms of the imidazole ring to which they are attached, the product obtained at the end of said process being a composition comprising the modified polymer (III), or the modified polymer (III) itself.

[0049] Polymer

[0050] A "grafted or graft-modified polymer" is defined as a polymer containing functional groups that have been introduced into the polymer chain after its polymerization. In practice, a grafted polymer is obtained by grafting a compound bearing a functional group capable of forming a covalent bond with an unsaturation in the polymer chain. The grafting reaction is therefore the covalent attachment of the compound of formula (I) to unsaturates in the polymer chain. Subsequent modification of the grafted polymer by covalent attachment of the compound of formula (II) results in the modified polymer.

[0051] As is known, a polymer generally comprises at least one main polymer chain. This polymer chain can be considered main when all other chains in the polymer are considered pendant chains, as mentioned in the document "Glossary of basic terms in polymer science" (IUP AC recommendations 1996), PAC, 1996, 68, 2287, p2294. "Unsaturation" refers to a multiple covalent bond between two carbon atoms; this multiple covalent bond can be a carbon-carbon double bond or a carbon-carbon triple bond, preferably a carbon-carbon double bond.

[0052] For the purposes of this invention, the term "initial polymer chain" or "starting polymer" refers to the polymer chain prior to the grafting reaction; this chain comprises at least one unsaturation capable of reacting with the compound of formula (I) described above. The initial polymer is therefore the polymer used as the starting reagent in the grafting reaction. The grafting reaction allows a modified polymer to be obtained from an initial polymer.

[0053] As previously stated, the initial polymer is a polymer comprising in its chain at least one unsaturation capable of reacting with the compound of formula (I) described above.

[0054] Even more preferably, the initial polymer is an elastomer, preferably a diene elastomer.

[0055] By "dienic" elastomer (or indistinctly rubber), whether natural or synthetic, should be understood in a known way as an elastomer consisting at least in part (i.e., a homopolymer or a copolymer) of diene monomer units (monomers bearing two carbon-carbon double bonds, conjugated or not).

[0056] These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". Generally, "essentially unsaturated" refers to a diene elastomer derived at least in part from conjugated diene monomers, having a proportion of diene motifs or units (conjugated dienes) greater than 15% (mole percent); thus, diene elastomers such as butyl rubbers or EPDM-type diene-alpha-olefin copolymers do not fall under the previous definition and can be described as "essentially saturated" diene elastomers (low or very low proportion of diene motifs, always less than 15%).

[0057] The term "diene elastomer suitable for use in the context of the present invention" specifically refers to:

[0058] - any homopolymer of a diene monomer, conjugated or not, having from 4 to 18 carbon atoms; - any copolymer of a diene, conjugated or not, having from 4 to 18 carbon atoms and at least one other monomer.

[0059] The other monomer can be ethylene, an olefin or a diene, conjugated or not.

[0060] Suitable conjugated dienes are those having 4 to 12 carbon atoms, in particular 1,3-dienes, such as 1,3-butadiene and isoprene.

[0061] Suitable as unconjugated dienes are unconjugated dienes having 6 to 12 carbon atoms, such as 1,4-hexadiene, ethylidene norbomene, dicyclopentadiene.

[0062] Suitable olefins include vinylaromatic compounds with 8 to 20 carbon atoms and aliphatic α-monoolefins with 3 to 12 carbon atoms.

[0063] Examples of suitable vinylaromatic compounds include styrene, ortho-, meta-, para-methylstyrene, the commercial mixture "vinyl-toluene", and para-tert-butylstyrene.

[0064] Acyclic a-monoolefins with 3 to 18 carbon atoms are particularly suitable as aliphatic a-monoolefins.

[0065] More specifically, diene elastomer is:

[0066] - any homopolymer of a conjugated diene monomer, in particular any homopolymer obtained by polymerization of a conjugated diene monomer having 4 to 12 carbon atoms;

[0067] - any copolymer obtained by copolymerization of one or more dienes conjugated together or with one or more vinylaromatic compounds having 8 to 20 carbon atoms;

[0068] - a copolymer of isobutene and isoprene (butyl rubber), as well as halogenated versions, in particular chlorinated or brominated, of this type of copolymer.

[0069] - any copolymer obtained by copolymerization of one or more dienes, conjugated or not, with ethylene, an α-monoolefin or their mixture such as for example elastomers obtained from ethylene, propylene with a non-conjugated diene monomer of the aforementioned type.

[0070] Preferably, the initial polymer can be a diene elastomer selected from the group consisting of ethylene-propylene-diene monomer copolymers (EPDM), butyl rubber (IRR), natural rubber (NR), synthetic polyisoprenes (IR), polybutadienes (BR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

[0071] Preferably, the initial polymer can be a diene elastomer selected from the group consisting of ethylene-propylene-diene monomer (EPDM) copolymers, butyl rubber (IRR), natural rubber (NR), synthetic polyisoprenes (IR), polybutadienes (BR), butadiene-styrene copolymers (SBR), ethylene-butadiene copolymers (EBR), isoprene-butadiene copolymers (BIR) or isoprene-butadiene-styrene copolymers (SBIR), isobutene-isoprene copolymers (butyl rubber - HR), isoprene-styrene copolymers (SIR) and mixtures of these elastomers.

[0072] Preferably, the initial polymer can be a diene elastomer selected from the group consisting of ethylene-propylene-diene monomer copolymers, butyl rubber and mixtures of these rubbers.

[0073] Preferably, the initial polymer may be a diene elastomer selected from the group consisting of natural rubber, synthetic polyisoprenes, polybutadienes, butadiene copolymers, isoprene copolymers, and mixtures of these elastomers. More preferably, the initial polymer may be a diene elastomer selected from the group consisting of natural rubber, synthetic polyisoprenes, polybutadienes, butadiene-styrene copolymers, ethylene-butadiene copolymers, isoprene-butadiene copolymers, isoprene-styrene copolymers, isoprene-butadiene-styrene copolymers, isobutene-isoprene copolymers, isoprene-styrene copolymers, and mixtures of these elastomers. Even more preferably, the initial polymer can be a diene elastomer chosen from the group consisting of natural rubber, synthetic polyisoprene and mixtures of these elastomers.

[0074] The starting polymers usable within the scope of the invention, preferably elastomers, more preferably diene elastomers, can have any microstructure that depends on the polymerization conditions used. These polymers can, for example, be block, random, sequenced, or microsequenced, and be prepared as dispersions, emulsions, or solutions. They can be coupled and / or star-shaped, for example, by means of a silicon or tin atom that links the polymer chains together.

[0075] According to the invention, the initial polymer, preferably an elastomer, more preferably a diene elastomer, having an unsaturation, preferably a carbon-carbon double bond, is modified by grafting a compound of formula (I) as defined above, also called a functionalizing agent.

[0076] According to formula (I), this functionalizing agent contains a Q group designating a dipole comprising at least one nitrogen atom.

[0077] For the purposes of this invention, "dipole" means a function capable of forming a 1,3 dipole addition on an unsaturated carbon-carbon bond.

[0078] Preferably, the dipole comprising at least one nitrogen atom is chosen from the group consisting of nitrile oxide, nitrone and nitrile imine.

[0079] For the purposes of this invention, nitrile oxide means a dipole corresponding to the formula -CN— >0, including its mesomeric forms.

[0080] Nitrile imine, in the context of the present invention, means a dipole corresponding to the formula -C=N^O, including its mesomeric forms.

[0081] For the purposes of this invention, nitrone means a dipole corresponding to the formula - C=N(— >0)-, including its mesomeric forms.

[0082] More preferably, group Q is a group of formula (IVa), (IVb) or (IVc), preferably of formula (IVb), in which:

[0083] - the symbol * represents the connection of Q to A; and

[0084] - R4, R5 and RÔ are chosen independently from a hydrogen atom, a linear or branched alkyl in C1-C20, a cycloalkyl in C3-C30 possibly substituted by a hydrocarbon chain, an aryl in C6-C20 possibly substituted by a hydrocarbon chain.

[0085] By "hydrocarbon chain" is meant a chain comprising one or more carbon atoms and one or more hydrogen atoms. The hydrocarbon chain may be saturated or unsaturated, preferably saturated, linear, branched, or cyclic, and may comprise from 1 to 24 carbon atoms. Preferably, R4, R5, and R0 are chosen independently from a hydrogen atom, a linear or branched alkyl group in the C1-C20 range, a C3-C30 cycloalkyl group optionally substituted by a saturated C1-C24 hydrocarbon chain, or a C6-C20 aryl group optionally substituted by a saturated C1-C24 hydrocarbon chain. More preferably still, R4, Rs and RÔ are chosen, independently of each other, from among a hydrogen atom, an alkyl, linear or branched, in C1-C20, a cycloalkyl in C3-C30 possibly substituted by an alkyl, linear or branched, in CI-CÔ, an aryl in C6-C20 possibly substituted by an alkyl, linear or branched, in CI-CÔ.

[0086] According to formula (I), group A represents a C0-CM arenediyl ring, optionally substituted by one or more identical or different aliphatic hydrocarbon chains, preferably saturated, linear or branched, optionally substituted or interrupted by one or more heteroatoms.

[0087] For the purposes of this invention, an "arendiyl ring" is defined as a monocyclic or polycyclic aromatic hydrocarbon group derived from an arene in which two hydrogen atoms have been removed. An arendiyl ring is therefore a divalent group.

[0088] By "monocyclic or polycyclic aromatic hydrocarbon group," we mean one or more aromatic rings whose backbone is composed of carbon atoms. In other words, there are no heteroatoms in the ring's backbone. The arenediyl ring can be monocyclic, that is, composed of a single ring, or polycyclic, that is, composed of several condensed aromatic hydrocarbon rings; such condensed rings then share at least two successive carbon atoms. These rings can be orthocondensed or ortho- and pericondensed. Preferably, when the arenediyl ring is substituted by one or more identical or different aliphatic hydrocarbon chains, independent of each other, this chain or these chains are inert with respect to the epoxide function and the Q group.

[0089] For the purposes of this invention, "inert hydrocarbon chain(s) with respect to the epoxide function and the Q group" means a hydrocarbon chain that does not react with either the epoxide function or the Q group. Thus, the inert hydrocarbon chain with respect to the function and the Q group is, for example, a hydrocarbon chain that does not contain alkenyl or alkynyl groups capable of reacting with the function or the Q group. Preferably, these hydrocarbon chains are saturated and may comprise from 1 to 24 carbon atoms. Preferably, the A group is a C0-CM arenediyl ring, optionally substituted by one or more identical or different aliphatic hydrocarbon chains, saturated at C1-C24, optionally substituted or interrupted by one or more heteroatoms.More preferably still, group A is an arendiyl ring in CÔ-CM, possibly substituted by one or more alkyl group(s), identical or different, in C1-C12, (more preferably in CI-CÔ, more preferably in C1-C4) or substituted by an -O-R3 group in which R3 is an alkyl in C1-C12, preferably in CI-CÔ, more preferably in C1-C4.

[0090] Preferably, the compound of formula (I) is chosen from the following compounds of formula (la) and (Ib): in which:

[0091] - the Q group is as defined previously; preferably is chosen from the group consisting of nitrile oxide, nitrone and nitrile imine, more preferably Q is nitrile oxide of formula (IVb);

[0092] - a grouping chosen from R7 to Ru of formula (la) and a grouping chosen from R7 to R13 of formula (Ib) designates the group according to formula (V),

[0093] E, Xi, X2 and X3 being as described above,

[0094] - the four other groups from R7 to Ru of formula (la) and the six other groups from R7 to R13 of formula (Ib), identical or different, represent independently of each other, a hydrogen atom or a hydrocarbon chain, aliphatic, preferably saturated, linear or branched, possibly substituted or interrupted by one or more heteroatoms.

[0095] The group according to formula (V) is also referred to in the remainder of the application as 'group of formula E' – epoxide group according to formula (V). Preferably, said hydrocarbon chain in the compounds of formula (la) and (1b) is inert with respect to the epoxide group and the Q group. Preferably, said hydrocarbon chain is saturated and may comprise from 1 to 24 carbon atoms, optionally substituted or interrupted by one or more heteroatoms. Preferably, said hydrocarbon chain is a C1-C12 alkyl (more preferably C1-C2, more preferably C1-C4) or a group selected from -OR3, -NHR3, -SR3, R3 being a C1-C12 alkyl, more preferably C1-C2, more preferably C1-C4.

[0096] According to a preferred embodiment of the invention, in formula (la), Rs represents an E-epoxide group according to formula (V), and R7, R9, R10, and Ru, identical or different, represent a hydrogen atom or a linear or branched hydrocarbon chain, preferably saturated at C1-C24, optionally substituted or interrupted by one or more heteroatoms. More preferably, Rs represents an E-epoxide group according to formula (V), and R7, R9, R10, and Ru, identical or different, represent a hydrogen atom or a C1-C12 alkyl group (more preferably C1-C2, more preferably C1-C4) or a group selected from -OR3, -NHR3, -SR3, R3 being a C1-C12 alkyl group, more preferably C1-C2, more preferably C1-C4.

[0097] More preferably in this embodiment, Rs represents a group of formula E-epoxide group according to formula (V), R10 represents a hydrogen atom, and R7, R9, and R11 represent a linear or branched hydrocarbon chain, preferably saturated at C1-C24, optionally substituted or interrupted by one or more heteroatoms. More preferably still, Rs represents a group of formula E-epoxide group according to formula (V), R10 represents a hydrogen atom, and R7, R9, and Ru represent a C1-C12 alkyl, more preferably C1-C2, more preferably C1-C4, or a group selected from -OR3, -NHR3, -SR3, R3 being a C1-C12 alkyl, more preferably C1-C2, more preferably C1-C4.

[0098] According to another preferred embodiment of the invention, in formula (a), R9 represents an E-epoxide group according to formula (V), and R7, Rs, R10, and Ru, identical or different, represent a hydrogen atom or a hydrocarbon chain, linear or branched, preferably saturated at C1-C24, optionally substituted or interrupted by one or more heteroatoms. More preferably, R9 represents an E-epoxide group according to formula (V), and R7, Rs, R10, and Ru, identical or different, represent a hydrogen atom or a C1-C12 alkyl group (more preferably C1-C2, more preferably C1-C4) or a group selected from -OR3, -NHR3, -SR3, R3 being a C1-C12 alkyl group, more preferably C1-C2, more preferably C1-C4.

[0099] More preferably in this embodiment, R9 represents an epoxy group of formula E according to formula (V), R7, Rs, and Ru represent a hydrogen atom, and R10 represents a linear or branched hydrocarbon chain, preferably saturated at C1-C24, optionally substituted or interrupted by one or more heteroatoms. More preferably still, Rs represents an epoxy group of formula E according to formula (V), R7, Rs, and Ru represent a hydrogen atom, and R10 represents a C1-C12 alkyl, more preferably C1-C2, more preferably C1-C4, or a group selected from -OR3, -NHR3, -SR3, R3 being a C1-C12 alkyl, more preferably C1-C2, more preferably C1-C4.

[0100] According to another preferred embodiment of the invention, in formula (Ib), R7 represents an E-epoxide group according to formula (V), and Rs to R13, identical or different, represent a hydrogen atom or a linear or branched hydrocarbon chain, preferably saturated at C1-C24, optionally substituted or interrupted by one or more heteroatoms. More preferably, R7 represents an E-epoxide group according to formula (V), and Rs to R13, identical or different, represent a hydrogen atom or a C1-C12 alkyl group (more preferably C1-C2, more preferably C1-C4) or a group selected from -OR3, -NHR3, -SR3, R3 being a C1-C12 alkyl group, more preferably C1-C2, more preferably C1-C4.More preferably in this embodiment, R7 represents a group of epoxide of formula E-group according to formula (V) and R8 to R13, identical, represent a hydrogen atom.

[0101] According to the compounds of formula (I), (la), and (Ib), group E is a C1-C20 hydrocarbon divalent bonding group that may optionally contain one or more heteroatoms. For the purposes of this invention, "hydrocarbon divalent bonding group" means a spacer group forming a bridge between group A in formula (I) and the epoxide group in formula (I). This spacer group is a hydrocarbon chain, saturated or unsaturated, preferably C1-C20 saturated, linear or branched, that may optionally contain one or more heteroatoms such as, for example, N, O, and S. This hydrocarbon chain may optionally be substituted, provided that the substituents do not react with group Q and the group of formula (V) as defined above.Preferably, in compounds of formula (I), (la) and (Ib), the E group is a linear or branched hydrocarbon chain, preferably saturated in C1-C20, more preferably in C1-C10, even more preferably in Cl-CÔ, possibly interrupted by one or more nitrogen, sulfur or oxygen atoms.

[0102] Preferably, in compounds of formula (I), (la), and (Ib), the E group is selected from the group consisting of -R14-, -NH-R14-, -O-R14-, and -S-R14-, where R14 is a linear or branched C1-C20 diyl alkane, preferably C1-C10, more preferably C1-C20. Even more preferably, in compounds of formula (I), (la), and (Ib), the E group is selected from the group consisting of -R14- and -O-R14-, where R14 is a linear or branched C1-C20 diyl alkane, preferably C1-C10, more preferably C1-C20.

[0103] Even more preferably, in compounds of formula (I), (la) and (Ib), the E group is chosen from -(CH2) n - with n=1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 and -O-(CH2) n - n=1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0104] According to the compounds of formula (I), (la) and (Ib), the groups Xi, X2, X3 of the epoxide group are identical or different, represent a hydrogen atom, an alkyl in CI-CO OR an aryl in CO-CM.

[0105] Even more preferentially, Xi, X2 and X3, being identical, are a hydrogen atom.

[0106] Preferably, among the compounds of formula (la) and (Ib), the compound of formula (Via) and the compound of formula (Vlb) are respectively preferred: in which:

[0107] - a grouping chosen from R7 to Ru of formula (la) and a grouping chosen from R7 to R13 of formula (Ib) designates the group according to formula (V), such that: E is an -O-R14- group with R14 a linear or C1-C10 branched diyl alkane; Xi, X? and X3 are hydrogen atoms,

[0108] - the four other groupings among R7 to Ru of formula (la) and the six other groupings among R7 to R13 of formula (Ib) are as described above.

[0109] Preferably, the compounds (Via) are such that the Rs group denotes the E-formula epoxide group according to formula (V), R10 represents a hydrogen atom and R7, R9 and R11 represent a C1-C4 alkyl.

[0110] Preferably, the compounds (Via) are such that the R9 group denotes the E-formula epoxide group according to formula (V), R7, Rs and Ru represent a hydrogen atom and R10 represents an -OR3 group, R3 being a C1-C4 alkyl.

[0111] Preferably, the compounds (Vlb) are such that R7 denotes the group of formula E- epoxide group according to formula (V) and Rs to R13, identical, represent a hydrogen atom.

[0112] More preferably, the compound of formula (I) is chosen from among the compounds of formula (Via) and (Vlb), more particularly is chosen from the group consisting of the compounds:

[0113] Compounds of formula (I) can be synthesized in particular according to the processes described in W02019102131 A1, US20120046418A1, W02022003278 and W02023117844A1.

[0114] Grafting:

[0115] Step a) is a grafting step, on a starting polymer comprising at least one unsaturation, of the compound of formula (I) comprising an epoxide group as described above, said grafting step comprising a step (a1) of mixing said polymer and said compound of formula (I).

[0116] The grafting is carried out by cycloaddition [3+2] of the Q group of the compound of formula (I) onto said unsaturation.

[0117] The mechanism of this cycloaddition is illustrated in particular in document W02015059269A1 pages 7 and 8.

[0118] Advantageously, the molar rate of the compound of formula (I) relative to the starting polymer ranges from 0.1% to 0.6%, preferably from 0.2% to 0.5%, even more preferably from 0.2% to 0.4%.

[0119] The molar ratio corresponds to the ratio of the number of moles of epoxide groups of the compound of formula (I) to the number of moles of monomer units constituting the starting polymer.

[0120] When the molar content is less than 0.1%, the polymer modification has a limited impact on the mechanical properties of rubber compositions containing reinforcing fillers. When the molar content is too high, the reinforcing properties are no longer optimal, and the mechanical properties, particularly elongation at break and tensile strength, are degraded.

[0121] Step (a1) is a mixing step of said polymer and said compound of formula (I).

[0122] This mixing step can be carried out in solution or in bulk, for example in an extruder, an internal mixer such as a Bandbury mixer, or an external mixer such as a roller mixer. Preferably, step (a1) is carried out in bulk.

[0123] Advantageously, step a1) is carried out in bulk, in an extruder, an internal mixer or in an external mixer.

[0124] Advantageously, step a1) is carried out at a temperature below 40°C, and is followed by a step a2) of heat treatment under press or in oven at temperatures ranging from 40°C to 200°C or step a) consists of step a1) carried out at a temperature above 60°C.

[0125] Other variations are possible depending on the nature of step b), which will be described later. Thus, according to one embodiment, step a) consists of step a1) carried out at a temperature below 40°C. In this case, step a) does not include any further heat treatment.

[0126] When grafting is carried out on a large scale, it is preferably done in the presence of an antioxidant.

[0127] According to another embodiment, the grafting step can be carried out in solution, either continuously or batchwise. The polymer thus obtained can be separated from its solution by any means known to those skilled in the art, and in particular by steam stripping.

[0128] Step b)

[0129] Step b) is a reaction step between the grafted polymer obtained at the end of step (a) and a compound of formula (II) to obtain the modified polymer (III), said reaction step comprising a mixing step (b1) of said grafted polymer and said compound of formula (II) as follows: in which Z, Y, R and R', identical or different, represent a hydrogen atom, an alkyl in CI-CO, a (CI-CO)alkyl-aryl in CO OR an aryl in CO-CM, possibly including one or more heteroatoms, Y and Z being able to form together a ring, in particular aromatic, with the carbon atoms of the imidazole ring to which they are attached.

[0130] Preferably, the compound of formula (II) may be chosen from the group consisting of 1-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 1-benzyl-2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1,2-dimethylimidazole and mixtures of these compounds.

[0131] According to a preferred embodiment, Y and Z are a hydrogen atom.

[0132] According to another preferred embodiment, Y and Z together form an aromatic ring, with the carbon atoms of the imidazole ring to which they are attached, preferably Y and Z form a benzene ring.

[0133] R and R' can be identical and represent an alkyl in CI-CO.

[0134] R and R' can be different. In this case, R' can be a hydrogen atom and R an alkyl in C1-C3, preferably in C1-C3.

[0135] Advantageously:

[0136] Y and Z are hydrogen atoms

[0137] R' is a hydrogen atom and R is an alkyl in C1-C3, preferably in C1-C3.

[0138] Advantageously, compound II is chosen from the following compounds (Ha) and (llb):

[0139] Compounds of formula (II), including compounds of formulas (Ha) and (llb), are available from suppliers such as Sigma Aldrich, Evonik...

[0140] Step b) is a reaction step between the grafted polymer obtained at the end of step (a) and a compound of formula (II) consisting of the partial or total opening by nucleophilic attack of compound (II) on the epoxide rings distributed along the chain of the grafted polymer obtained at the end of step a).

[0141] Advantageously, the molar ratio of the compound of formula (II) with respect to the grafted polymer obtained at the end of step a) ranges from 20% to 125%, preferably from 40% to 120%, even more preferably from 50% to 120% of the molar ratio of the compound of formula (I) incorporated in step a).

[0142] Thus, advantageously, the ratio of the molar rate of the compound of formula (II) to the molar rate of the compound of formula (I) goes from 20% to 125%, preferably from 40% to 120%, even more preferably from 50% to 120%.

[0143] This ratio corresponds to the ratio of the molar content of imidazole groups of compound of formula (II) to the molar content of epoxide groups of compound of formula (I) incorporated during step a), multiplied by 100.

[0144] When the rate is less than 20%, no significant improvement in the mechanical properties of the rubber compositions, in particular no improvement in the strengthening properties, is observed compared to the polymer not having undergone step b) of modification.

[0145] In preferred ranges, polymer modification improves tensile strength without altering the MA300 / MA100 parameter. Elongation at break can also be improved. When the rate exceeds 125%, both elongation at break and tensile strength are reduced.

[0146] Thus, compound (II) may be in slight excess relative to component (I). In this case, the modified polymer contains nitrogenous and hydroxyl heterocyclic functions.

[0147] Otherwise, not all epoxide functions react with compound (II) and the modified polymer then contains epoxide, nitrogen heterocycle and hydroxyl functions.

[0148] Step (b1) is a mixing step of the grafted polymer obtained at the end of step a) and the compound of formula (II).

[0149] As with step a1) described previously, this mixing step can be carried out in bulk, for example in an extruder, an internal mixer or in an external mixer such as a roller mixer, or in solution.

[0150] Advantageously, step b1) is carried out in bulk, in an extruder, an internal mixer or in an external mixer.

[0151] Advantageously, step b1) is carried out at a temperature below 40°C, and is followed by a step b2) of heat treatment under press or in oven at temperatures ranging from 40°C to 200°C, preferably from 80°C to 200°C, even more preferably between 100°C and 200°C, or step b) consists of step b1) carried out at a temperature above 60°C.

[0152] Advantageously, steps a1) and b1) are carried out in bulk, for example in an extruder, an external mixer or an internal mixer, and step a1) is carried out at a temperature below 40°C, and is followed by a heat treatment step a2) under press or in oven at temperatures from 40°C to 200°C, or step a) consists of step a1) carried out at a temperature above 60°C; and step b1) is carried out at a temperature below 40°C, and step b1) is followed by a step b2) of heat treatment under press or in oven at temperatures ranging from 40°C to 200°C, preferably from 80°C to 200°C, even more preferably between 100°C and 200°C, or and step b) consists of step b1) carried out at a temperature above 60°C.

[0153] Other variations in the implementation of steps a) and b) are possible.

[0154] Thus, according to one embodiment, steps a1) and b1) are carried out in bulk, for example in an extruder, an external mixer or an internal mixer and step a) consists of step a1) carried out at a temperature below 40°C, and step b1) is carried out at a temperature below 40°C and is followed by a heat treatment step b2) under pressure or in an oven at temperatures from 40°C to 200°C, preferably from 80°C to 200°C, even more preferably between 100°C and 200°C, or step b1) is carried out at a temperature above 60°C.

[0155] This method of implementation is advantageous from an industrial point of view since it allows minimizing the number of steps in the process.

[0156] When the modification in step b) is carried out on a large scale, it is preferably carried out in the presence of an antioxidant.

[0157] Step b) can be carried out prior to the introduction of the modified polymer into the rubber composition, or during the manufacture of the composition.

[0158] According to another embodiment, step b) can be carried out in solution, either continuously or batchwise. The modified polymer thus obtained can be separated from its solution by any means known to those skilled in the art, and in particular by steam stripping.

[0159] Modified polymer (III)

[0160] The modified polymer (III) has the formula (Ilia) if R'=H or (lllb) if R' is different from H:

[0161] * representing the bond to the starting polymer.

[0162] The groups Xi, X?, X3, Y and Z are as described above.

[0163] The link to the starting polymer consists of the E, A groups, and the covalent link resulting from the [3+2] cycloaddition of the Q group of the compound of formula (I) on at least one unsaturation of said polymer, the E, A and Q groups being as described above.

[0164] Advantageously, the starting polymer is an elastomer, preferably a diene elastomer as described above.

[0165] Advantageously, the molar rate of the compound of formula (I) relative to the starting polymer ranges from 0.1% to 0.6%, preferably from 0.2% to 0.5%, even more preferably from 0.1% to 0.4%.

[0166] Therefore, only a fraction of the unsaturates of the initial polymer reacts with the compound of formula (I).

[0167] Advantageously, the ratio of the molar rate of the compound of formula (II) to the molar rate of the compound of formula (I) goes from 20% to 125%, preferably from 40% to 120%, even more preferably from 50% to 120%.

[0168] The modified polymer (III) contains epoxide, nitrogen heterocycle and hydroxyl functions.

[0169] The product obtained at the end of the process as described above may be a composition comprising the modified polymer (III), or the modified polymer (III) itself. According to some embodiments, a portion of the reactants, in particular the compound of formula

[0170] (II) may not react during the process, so that the product obtained at the end of the process contains the modified polymer (III) but also the unconsumed reactants. The product obtained at the end of the process may thus be a composition comprising the modified polymer

[0171] (III), of formula (Ilia) or (lllb) as described above.

[0172] According to other embodiments, the reactants are consumed during the process so that the product obtained at the end of the process can be the modified polymer (III) itself, of formula (Ilia) or (lllb) as described below.

[0173] Composition comprising the modified polymer (III) or modified polymer (III) capable of being obtained according to the process described above

[0174] An object of the invention relates to a composition that can be obtained according to the process described above comprising a modified polymer (III), of formula (Ilia) or (lllb) as described above.

[0175] The composition containing the modified polymer (III) can be purified to remove unconsumed reagents, in particular the unreacted compound of formula (II). This purification step allows the modified polymer of formula (III) to be isolated.

[0176] This purification step can be carried out by any means known to a person skilled in the art, for example by filtration or washing.

[0177] In this case, the process according to the invention further includes a step c) of purifying the composition obtained at the end of step b).

[0178] Another object of the invention relates to a modified polymer (III) of formula (Ilia) or (lllb) as described above and capable of being obtained according to the process described above.

[0179] The modified polymer (III) of formula (Ilia) or (lllb) can be obtained directly at the end of step b) or after implementation of step c).

[0180] Rubber composition

[0181] Another object of the invention relates to a rubber composition based on at least one reinforcing filler, a crosslinking system and at least: - a composition comprising a modified polymer (III), said composition being as described above or obtained according to the process described above;

[0182] - and / or a modified polymer (III) as described above or obtained by the process as described above.

[0183] The rubber compound contains various types of reinforcing fillers, known for their ability to strengthen a rubber compound suitable for tire manufacturing. Examples include organic fillers such as carbon black, inorganic reinforcing fillers such as silica combined with a known coupling agent, or mixtures of both. Such reinforcing fillers typically consist of nanoparticles with an average size (by mass) of less than one micrometer, generally less than 500 nm, most often between 20 and 200 nm, and particularly and preferentially between 20 and 150 nm.

[0184] According to a particular embodiment of the invention, the reinforcing filler comprises an inorganic filler, preferably silica. In this embodiment, the reinforcing inorganic filler represents more than 50% by mass of the mass of the reinforcing filler in the rubber composition. The reinforcing inorganic filler is then said to constitute the majority of the composition.

[0185] When combined with a predominant inorganic reinforcing agent such as silica, carbon black is preferably used at a concentration below 20%, and more preferably below 10% (for example, between 0.5 and 20%, particularly between 2 and 10%). Within these ranges, the coloring (black pigmenting agent) and UV-resistant properties of carbon black are beneficial without compromising the typical performance provided by the reinforcing inorganic agent.

[0186] The term "reinforcing inorganic filler" here refers to any inorganic or mineral filler, regardless of its color or origin (natural or synthetic), also called "white" filler, "light" filler, or even "non-black" filler (as opposed to carbon black), capable of reinforcing, on its own and without the need for an intermediate coupling agent, a rubber compound intended for tire manufacturing. It is well known that certain reinforcing inorganic fillers are characterized by the presence of hydroxyl groups (-OH) on their surface. Suitable reinforcing inorganic fillers include mineral fillers of the siliceous type, preferably silica (SiO₂), or of the aluminous type, particularly alumina (Al₂O₃).

[0187] The silica used can be any reinforcing silica known to a person skilled in the art, including any precipitated or pyrogenated silica.

[0188] Precipitated silica can be produced from non-renewable raw materials, including those derived from inorganic sand (silicon dioxide from inorganic sand), recycled materials such as foundry sands, end-of-life tires and in particular the treads of end-of-life tires which mainly contain silica as a reinforcing filler, or from bio-based raw materials such as organic waste from plants, preferably inedible organic waste from plants.

[0189] Non-renewable raw materials are defined as raw materials that do not regenerate on a human timescale. These are therefore exhaustible resources. Examples include minerals such as stones or sand, metals, gas, and oil.

[0190] Among the plants that contain silicon dioxide in their tissues are mustard, grasses, corn, sugarcane bagasse, rice, wheat, and in particular mustard husks, bamboo leaves, corn ears, rice husks, and wheat husks.

[0191] Silica derived from non-renewable raw materials such as natural inorganic sand is usually obtained by heating sand in a glass furnace in the presence of sodium carbonate. The resulting sodium silicate is then dissolved in water, possibly in the presence of a base such as sodium hydroxide. Precipitated synthetic silica is formed from this aqueous solution by controlled treatment of the silicate with an acid (e.g., a mineral acid and / or an acidifying gas such as carbon dioxide). Sometimes, an electrolyte (e.g., sodium sulfate) may be present to promote the formation of precipitated silica particles. The recovered precipitated silica is amorphous.

[0192] Silica derived from bio-based raw materials such as those mentioned above can, for example, be obtained by burning the bio-based raw material in order to recover the ash of this bio-based material which contains mainly silicon dioxide.For example, with rice husks, and in a process equivalent to that described above for silicas based on non-renewable or recycled mineral raw materials, rice husk ash is generally treated with a strong base such as sodium hydroxide to form an aqueous silicate solution (e.g., sodium silicate). Following this, precipitated synthetic silica is formed by the controlled addition of an acid (e.g., a mineral acid and / or an acidifying gas such as carbon dioxide) in which an electrolyte (e.g., sodium sulfate) may be present to promote the formation of precipitated silica particles derived from rice husks. The recovered precipitated silica is amorphous precipitated silica. Silica derived from rice husk ash is commonly referred to as RHA silica (Rice Husk Ash Silica).Bio-based silicas are available, for example, from suppliers such as Solvay, Evonik, Quechen, Wilmar International, Wuxi.

[0193] In summary, the synthesis of a precipitated silica usable within the scope of the invention can be carried out from a sodium silicate obtained entirely from bio-based, recycled, or non-renewable raw materials, but also from a mixture of bio-based and / or recycled and / or non-renewable raw materials. Preferably, the precipitated silica, whether obtained from mineral, non-renewable, recycled, or bio-based raw materials, has a specific surface area (BET) and a specific surface area (CTAB), both less than 450 m². 2 / g, preferably within a range of 30 to 400 m 2 / g, particularly from 60 to 300 m 2 / g.

[0194] Any type of precipitated silica can be used, including highly dispersible precipitated silicas (known as "HDS" for "highly dispersible" or "highly dispersible silica"). These precipitated silicas, whether highly dispersible or not, are well known to those skilled in the art. Examples include the silicas described in applications W003 / 016215-A1 and W003 / 016387-A1. Among commercial HDS silicas, the following can be used: "Ulsilsil® 5000GR" and "Ulsilsil® 7000GR" from Evonik, and "Zeosil® 1085GR", "Zeosil® 1115 MP", "Zeosil® 1165 MP", "Zeosil® Premium 200 MP", and "Zeosil® HRS 1200 MP" from Solvay.As non-HDS silica, the following commercial silicas may be used: “Ultrasil ® VN2GR”, “Ultrasil ® VN3GR” silicas from Evonik, “Zeosil® 175GR” silica from Solvay, “Hi-Sil EZ120G(- D)”, “Hi-Sil EZ160G(-D)”, “Hi-Sil EZ200G(-D)”, “Hi-Sil 243LD”, “Hi-Sil 210”, “Hi-Sil HDP 320G” silicas from PPG, “K160”, “K185”, “K195” silicas from Wilmar International.

[0195] In this presentation, 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 0.17]. For inorganic fillers such as silica, for example, the CTAB specific surface area values ​​were determined according to the NF ISO 5794-1 standard, 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.

[0196] Preferably, the total reinforcing filler content is between 30 and 160 parts per annum (ppm), more preferably between 40 and 160 ppm. Below 30 ppm, the reinforcement of the rubber compound is insufficient to provide an adequate level of cohesion or wear resistance for the rubber component of the tire comprising this compound. Even more preferably, the total reinforcing filler content is at least 50 ppm. Above 160 ppm, there is a risk of increased hysteresis and therefore increased rolling resistance of the tires. For this reason, the total reinforcing filler content is preferably in the range of 50 to 120 ppm, particularly for use in a tire tread. Any of these ranges of total reinforcing filler content can be applied to any of the embodiments of the invention.

[0197] To couple the reinforcing inorganic filler to the modified polymer, a coupling agent, in particular a silane (or linking agent), is used in a well-known manner. This agent must be at least bifunctional and ensure sufficient chemical and / or physical connection between the inorganic filler (the surface of its particles) and the modified polymer. Organosilanes or polyorganosiloxanes, at least bifunctional, are used in particular. More specifically, polysulfide silanes, described as "symmetric" or "asymmetric" depending on their specific structure, are used, as described, for example, in applications W003 / 002648 (or US 2005 / 016651) and W003 / 002649 (or US 2005 / 016650). Examples of polysulfurized silanes include polysulfides (especially disulfides, trisulfides or tetrasulfides) of bis-(alkoxyl(Ci-C4)-alkyl(Ci-C4)silyl-alkyl(Ci-C4)), such as bis(3-trimethoxysilylpropyl) or bis(3-triethoxysilylpropyl) polysulfides.Among these compounds, in particular, the tetrasulfide of bis(3-triethoxysilylpropyl), abbreviated TESPT, with the formula [(CzHsO^SilCHzhSz](CzHsO^SilCHzhSz), or the disulfide of bis-(triethoxysilylpropyl), abbreviated TESPD, with the formula [(C2H5O)3Si(CH2)3S]2, is used.

[0198] The coupling agent content is advantageously less than 20%, it being understood that it is generally desirable to use as little as possible. Typically, the coupling agent content represents 0.5% to 15% by weight relative to the amount of inorganic filler. Its content is preferably between 0.5% and 12%, and more preferably within the range of 3% to 10%. This content is easily adjusted by those skilled in the art according to the amount of inorganic filler used in the formulation.

[0199] The rubber composition according to the invention may also contain, in addition to coupling agents, coupling activators, inorganic filler covering agents or more generally processing aids capable of lowering the viscosity of the compositions, improving their processing ability in the raw state.

[0200] The rubber composition according to the invention may also comprise all or some of the usual additives commonly used in elastomer compositions intended to form external compounds of finished rubber articles such as tires, in particular treads, such as plasticizers or extending oils, pigments, protective agents such as ozone-blocking waxes, chemical ozone-blockers, antioxidants, anti-fatigue agents, reinforcing resins (such as resorcinol or bismaleimide), acceptors (e.g., novolac phenolic resin) or methylene donors (e.g., HMT or H3M) as described, for example, in application WO 02 / 10269

[0201] The crosslinking system can be any type of system known to those skilled in the art in the field of tire rubber compounds. It may, in particular, be sulfur-based, and / or peroxide-based, and / or bismaleimide-based. It may also be polyacid-based, including diacids as described in patent applications W02014095582 and W02014095585.

[0202] Preferably, the crosslinking system is sulfur-based; this is then 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 such as stearic acid salts and transition metal salts, guanidine derivatives (particularly diphenylguanidine), or known vulcanization retarders may be used.

[0203] Sulfur is used at a preferential rate of between 0.5 and 12 parts per thousand (ppm), particularly between 1 and 10 ppm. The vulcanization accelerator is used at a preferential rate of between 0.5 and 10 ppm, more preferably between 0.5 and 5.0 ppm.

[0204] Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur can be used as an accelerator, including thiazole-type accelerators and their derivatives, sulfenamide-type accelerators, thiurams, dithiocarbamates, dithiophosphates, thioureas and xanthates.

[0205] The rubber compound according to the invention is 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) at high temperature, up to a maximum temperature between 130°C and 200°C, followed by a second mechanical working phase (the so-called "productive" phase) at a lower temperature, typically below 110°C, for example between 40°C and 100°C, a finishing phase during which the crosslinking system is incorporated. The rubber compound according to the invention can be either in its raw state (before crosslinking or vulcanization) or in its cured state (after crosslinking or vulcanization).

[0206] Pneumatic

[0207] Another object of the invention relates to a semi-finished article for a pneumatic bandage for a non-pneumatic bandage, this semi-finished article comprising all or part of a rubber composition as described above.

[0208] Semi-finished products for pneumatic or non-pneumatic tires are rubber products intended for the manufacture of pneumatic or non-pneumatic tires. These can include any type of rubber strip, such as treads, crown reinforcement plies (e.g., working plies, protective plies, or reinforcement plies), carcass reinforcement plies, sidewall plies for pneumatic tires, bead plies, protector plies, underlayer plies, rubber block plies, and other plies providing the interface between the aforementioned areas of the tires.

[0209] Preferably, the semi-finished article for pneumatic or non-pneumatic tires is a tread.

[0210] As is well known, the tread of a pneumatic or non-pneumatic tire comprises a rolling surface designed to be in contact with the ground when the tire is in motion. The tread pattern includes tread elements or basic blocks delimited by various main grooves, which may be longitudinal, circumferential, transverse, or oblique. These basic blocks may also include various finer incisions or sipes. A "pneumatic tire" is defined as a tire designed to form a cavity by cooperating with a supporting element, such as a rim. This cavity is capable of being pressurized to a pressure higher than atmospheric pressure.A pneumatic tire usually consists of two beads intended to come into contact with a rim, a crown made up of at least one crown reinforcement and a tread, two sidewalls, the tire being reinforced by a carcass reinforcement anchored in the two beads.

[0211] In contrast, a "non-pneumatic tire" is a tire that supports a vehicle's load by means other than pressurized inflation gas. Thus, a non-pneumatic tire is a toroidal body made of at least one polymeric material, designed to perform the function of a tire but without being subjected to inflation pressure. A non-pneumatic tire can be solid or hollow. A hollow non-pneumatic tire may contain air, but at atmospheric pressure; that is, it lacks the pneumatic rigidity provided by inflation gas at a pressure higher than atmospheric pressure. A non-pneumatic tire typically consists of a base, designed, for example, for mounting on a rigid rim, a crown reinforcement that connects to a tread, and a deformable structure, such as spokes, ribs, or dimples, positioned between the base and the crown.Such non-pneumatic tires do not necessarily include a sidewall. Non-pneumatic tires are described, for example, in documents WO 03 / 018332 and FR2898077.

[0212] The pneumatic tires according to the invention are intended to equip in particular vehicles of all types such as passenger vehicles, two-wheeled vehicles, heavy goods vehicles - i.e. metro, bus, road transport vehicles (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering vehicles - aircraft, transport or handling vehicles or, more generally, on any rolling device.

[0213] Non-pneumatic tires are intended to be fitted in particular to passenger vehicles or two-wheelers.

[0214] Preferably, the pneumatic tires according to the invention are intended to equip passenger vehicles.

[0215] 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.

[0216] Examples 1. Methods

[0217] 1.1 Measurement of the number-average molar masses (Mn), weight-average molar masses (Mw) and the polydispersity index of elastomers

[0218] Size exclusion chromatography (SEC) is used. SEC separates macromolecules in solution according to their size using columns filled with a porous gel. The macromolecules are separated according to their hydrodynamic volume, with the largest eluting first. While not an absolute method, SEC allows for the determination of the molar mass distribution of an elastomer. Using commercial standard products, the various number-average (Mn) and weight-average (Mw) molar masses can be determined, and the polymolecularity index (Ip = Mw / Mn) can be calculated using a Moore calibration.

[0219] Preparation of the elastomer sample to be tested

[0220] No special preparation of the elastomer sample is required prior to analysis. It is simply solubilized to a concentration of approximately 1 g / L in chloroform or in the following mixture: tetrahydrofuran + 1% vol. diisopropylamine + 1% vol. triethylamine + 1% vol. distilled water (% vol. = % vol.). The solution is then filtered through a 0.45 µm pore size filter before injection.

[0221] SEC Analysis

[0222] The equipment used is a WATERS Alliance chromatograph. The deposition solvent is the following mixture: tetrahydrofuran + 1% vol. diisopropylamine + 1% vol. triethylamine or chloroform, depending on the solvent used to dissolve the elastomer. The flow rate is 0.7 mL / min, the system temperature is 35 °C, and the analysis time is 90 min. A set of four WATERS columns in series is used, with the trade names "STYRAGEL HMW7", "STYRAGEL HMW6E", and two "STYRAGEL HT6E".

[0223] The injected volume of the elastomer sample solution is 100 pL. The detector is a WATERS 2410 differential refractometer with a wavelength of 810 nm. The chromatographic data processing software is the WATERS EM POWER system. The calculated average molar masses are relative to a calibration curve created using commercially available PSS READY CAL-KIT polystyrene standards. 1.2 Characterization of compounds grafted onto diene elastomers

[0224] The molar content of compounds grafted onto dienic elastomers was determined by NMR analysis. Spectra were acquired on a 500 MHz BROKER spectrometer equipped with a CryoSonde BBFO-zgrad-5 mm. The quantitative 1H NMR experiment used a single 30° pulse sequence with a 5-second repetition interval between acquisitions. Samples were solubilized in deuterated chloroform (CDCL) to obtain a lock signal. 2D NMR experiments were used to verify the nature of the grafted motif by observing the chemical shifts of carbon and proton atoms.

[0225] 2. Preparation of 2-(glycidyloxy)-1-naphtonitrile oxide (compound A) and 2,4,6-trimethyl-3-((2-methyl-l / - / -imidazol-l-yl)methyl)benzonitrile oxide (compound B).

[0226] 2-(glycidyloxy)-1-naphtonitrile oxide (compound A, CAS No. 1357580-85-8) was synthesized according to the procedure described in US patent application 20120046418 - see formula (Life)

[0227] Compound C (ethyl-imidazole) with formula (llb) is also used.

[0228] (Hb)

[0229] Compounds A and C are used in the manufacturing process of a modified polymer according to the invention.

[0230] Compound B is used in the manufacturing process of a modified polymer outside the scope of this invention.

[0231] 3. Tests

[0232] Rubber compositions are characterized after cooking, as indicated below.

[0233] Traction tests

[0234] These tensile tests determine the breaking properties. Unless otherwise specified, they are carried out in accordance with the French standard NF T 46-002 of September 1988.

[0235] The tensile strengths (in MPa) and elongations at break (in %) are measured at 23°C ± 2°C according to standard NF T 46-002.

[0236] The nominal secant modulus (or apparent stress, in MPa) is measured at 100% elongation (noted MA100) and at 300% elongation (noted MA300) at the first elongation (i.e., after an accommodation cycle at the extension rate planned for the measurement itself).

[0237] 4. Preparation of rubber compositions

[0238] The following tests are conducted as follows: the modified or unmodified diene elastomer(s), reinforcing filler(s), and any coupling agent are introduced into an internal mixer, filled to 70% capacity and with an initial tank temperature of approximately 90°C. After one to two minutes of mixing, the various other ingredients, with the exception of the vulcanization system (sulfur and sulfenamide accelerator), are then added. A thermomechanical process (non-productive phase) is then carried out in a single step (total mixing time of approximately 5 minutes) until a maximum "drop" temperature of approximately 160°C is reached. The resulting mixture is collected, cooled, and then the vulcanization system (sulfur and sulfenamide accelerator) is added to an external mixer (homo-finisher) at 70°C, mixing everything together (productive phase) for approximately 5 to 6 minutes.

[0239] The rubber 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.

[0240] The test specimens are then placed under a press at a temperature of 150°C for 30 min.

[0241] 5. Tests

[0242] 5.1. Tests - Series 1

[0243] The same starting polymer is used for grafting. The polymers are grafted with compound A (as defined above), compound B (as defined above), or with compound A followed by compound C (ethylimidazole). The polymers are named according to the compound(s) grafted and their grafting ratio.

[0244] Thus, a polymer named “polymer A 0.3% - ethyl-imidazole 0.3%” corresponds to a polymer grafted by compound A at a molar rate of 0.3% and then by the compound ethyl-imidazole at a molar rate of 0.3%.

[0245] Functional polymers

[0246] • Functional polyisoprene A 0.3%

[0247] 2-(glycidyloxy)-1-naphtonitrile oxide (compound A) of 93% purity (229 mg, 0.882 mmol, i.e., a mole fraction of 0.3 mol%), with an NMR purity of 94 mol%, is incorporated into 20 g of synthetic polyisoprene (containing 99.35% by weight of cis-1,4-isoprene units and 0.65% by weight of isoprene-3,4- units; Mn = 375,000 g / mol and lp = 3.6, measured according to the method described above) using a roller tool (external mixer at 30°C). The mixture is homogenized in 15 wallet passes. This mixing phase is followed by heat treatment (10 min at 80°C) under a press at 10 bar pressure.

[0248] • Functional polyisoprene A 0.5%

[0249] The process is identical to that of 0.3% polyisoprene A, except that compound A (381 mg, 1.47 mmol, i.e., a mole fraction of 0.5 mol%) is incorporated into the synthetic polyisoprene. • Functional polyisoprene A 1%

[0250] The process is identical to that of polyisoprene A 0.3% except that compound A (763 mg, 2.94 mmol or a mole fraction of 1% mol) is incorporated into the synthetic polyisoprene.

[0251] • Functional polyisoprene B 0.3%

[0252] 2,4,6-Trimethyl-3-((2-methyl-l / - / -imidazol-l-yl)methyl)benzonitrile oxide (Compound B), with an NMR purity of 94 mol% (0.255 g, 1.47 mmol, i.e., a mole fraction of 0.3 mol%), is incorporated into 20 g of synthetic polyisoprene (containing 99.35% by weight of cis-1,4-isoprene units and 0.65% by weight of cis-3,4-isoprene units; Mn = 375,000 g / mol and lp = 3.6, measured according to the method described above) using a roller tool (external mixer at 30°C). The mixture is homogenized in 15 wallet passes. This mixing phase is followed by heat treatment (10 min at 120°C) under a press at 10 bar pressure.

[0253] • composition comprising polyisoprene and compound C, denoted C 0.5%

[0254] 2-Ethyl imidazole (compound C) from Aldrich (0.144 g, 1.47 mmol, i.e., a mole fraction of 0.5 mol%) is incorporated into 20 g of synthetic polyisoprene (containing 99.35% by weight of cis-1,4-isoprene units and 0.65% by weight of 3,4-isoprene units; Mn = 375,000 g / mol and lp = 3.6, measured according to the method described above) using a roller mill (external mixer at 30°C). The mixture is homogenized in 15 wallet passes. This mixing phase is followed by heat treatment (10 min at 150°C) under a press at 10 bar pressure.

[0255] Compound C is not grafted onto polyisoprene.

[0256] • Functional polyisoprene A 0.3% - C 0.35%

[0257] 2-Ethylimidazole (compound C) from Aldrich (0.100 g, 1.03 mmol, i.e., a mole fraction of 0.35 mol%) is incorporated into 20.23 g of 0.3% functional polyisoprene A using a roller mill (external mixer at 30°C). The mixture is homogenized in 15 wallet passes. This mixing phase is followed by a heat treatment (10 min at 150°C) under a press at 10 bar pressure.

[0258] • Functional polyisoprene A 0.3% - C 0.5%

[0259] The process is identical to that of polyisoprene A 0.3% - C 0.35%, except that 2-ethylimidazole (compound C - 0.144 g, 1.47 mmol, i.e., a mole fraction of 0.5 mol%) is incorporated into polyisoprene A 0.3%. • Functional polyisoprene A 0.5% - C 0.2%

[0260] 2-Ethylimidazole (compound C) from Aldrich (0.059 g, 0.61 mmol, i.e., a mole fraction of 0.2 mol%) is incorporated into 20.381 g of 0.5% functional polyisoprene A using a roller mill (external mixer at 30°C). The mixture is homogenized in 15 wallet passes. This mixing phase is followed by a heat treatment (10 min at 150°C) under a press at 10 bar pressure.

[0261] • Functional polyisoprene A 0.5% - C 0.35%

[0262] The process is identical to that of polyisoprene A 0.5% - C 0.2% except that 2-ethyl imidazole (0.100 g, 1.03 mmol mmol i.e. a molar fraction of 0.35% mol) is incorporated into functional polyisoprene A 0.5%.

[0263] • Functional polyisoprene A 0.5% - C 0.5%

[0264] The process is identical to that of polyisoprene A 0.5% - C 0.2% except that 2-ethyl imidazole (0.144 g, 1.47 mmol i.e. a mole fraction of 0.5% mol) is incorporated into functional polyisoprene A 0.5%.

[0265] • Functional polyisoprene A 1% - C 0.5%

[0266] 2-Ethylimidazole (compound C) of 98% purity from Aldrich (0.144 g, 1.47 mmol, i.e., a mole fraction of 0.5 mol%) is incorporated into 20.76 g of 1% functional polyisoprene A using a roller mill (external mixer at 30°C). The mixture is homogenized in 15 wallet passes. This mixing phase is followed by a heat treatment (10 min at 150°C) under a press at 10 bar pressure.

[0267] Rubber compositions and results

[0268] Rubber compositions comprising the polymers were prepared as previously indicated in section 4, some of which conform to the invention (denoted Cx) and some of which do not conform (denoted NCx).

[0269] All rubber compositions have the same quantitative formulation, with quantities expressed as parts by weight per hundred parts of elastomer (pwc), i.e.:

[0270] 100 pcs of functionalized or non-functionalized synthetic polyisoprene;

[0271] 3 pieces of ASTM N234 grade carbon black (ASTM D1765-17) marketed by Cabot Corporation;

[0272] 60 pc of silica “Zeosil 1165MP” marketed by Solvay; 1 pc of antioxidant: 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) marketed by the company Flexys;

[0273] 5 pieces of paraffin

[0274] 1.5 pc of antioxidant: N-1,3-dimethylbutyl-N-phenyl-para-phenylenediamine marketed by Flexys under the reference "Santaflex 6-PPD";

[0275] 6 pc of a coupling agent of silica to diene elastomer: Bis[3- (triethoxysilyl)propyl] tetrasulfide silane (TESPT) marketed by Evonik under the reference "Si69";

[0276] 2.5 pc of stearic acid: stearin “Pristerene 4031” marketed by the company Uniquema;

[0277] 2.7 pc of zinc oxide (industrial grade - Umicore company);

[0278] 1.65 pc of N-cyclohexyl-2-benzothiazyl-sulfenamide accelerator marketed by Flexys under the reference "Santocure CBS"; and 1.33 pc of sulfur.

[0279] A reference rubber composition based on unfunctionalized polysiprene is used to compare the mechanical properties of the rubber compositions (results base 100).

[0280] The extensometry results at 23 °C are shown in Tables 1 (rubber compositions outside the invention) and 2 (rubber compositions according to the invention).

[0281] [Table 1]

[0282] [Table 2]

[0283] The MA300 / MA100 parameter characterizes the strengthening properties induced by the polymer modification. The higher this parameter, the greater the strengthening properties, which is linked to better interaction between the rubber and the fillers.

[0284] It is desirable to have polymers that promote the dispersion of charges (for which the MA300 / MA100 ratio of the rubber composition is high) without causing excessive degradation of mechanical properties such as elongation at break and even allowing, where appropriate, for an increase in elongation at break.

[0285] The results in Table 1 show that: increasing the grafting rate of compound A (carrying an epoxy group) is accompanied by a decrease in the elongation at break and the stress at break of the rubber composition, at the same grafting rate (0.3%), grafting of compound B (carrying an imidazole group) leads to a significant decrease in the elongation at break of the rubber composition compared to a rubber composition using a polymer grafted with compound A, compound C has no impact on the MA / 300 / MA100 parameter of the rubber compositions.

[0286] Comparing the results in Tables 1 and 2 shows that, surprisingly, compared to the rubber composition with the polymer grafted with 0.3% of compound A (containing an epoxy group) – composition NC1 – modifying this polymer with 0.35% compound C (composition C1) improves the tensile strength without altering the MA300 / MA100 parameter or the elongation at break. When the percentage of compound C is 0.5% (composition C2), both the elongation at break and the tensile strength are reduced. Compared to the rubber composition with the polymer grafted with 0.5% of compound A (carrying an epoxy group) - NC2 rubber composition, the modification of this polymer by compound C at a rate of 0.2%, 0.35% or 0.5% (respective rubber compositions C3, C4 and C5) makes it possible to improve the breaking strength without significantly modifying the MA300 / MA100 parameter and the elongation at break.

[0287] 5.2. Tests - Series 2:

[0288] In this second series of tests, functional polyisoprene A 0.5% - C 0.5% is manufactured by modifying the manufacturing process parameters according to several variations. In particular, the grafting of compound A is carried out using either an external or internal mixer, and the modification of the grafted polymer with compound C is also carried out using either an external or internal mixer.

[0289] 5.2.1. Process for preparing rubber compositions with a functional polymer (grafting of compound A in an external mixer with heat treatment and modification of the grafted polymer with compound C in an external mixer with heat treatment of variable duration) - variant 1

[0290] Functional polymers

[0291] • Functional polyisoprene A 0.5% - C 0.5% according to the process described in section 5.1. (reference)

[0292] 2-(glycidyloxy)-1-naphtonitrile oxide (compound A) of 93% purity (381 mg, 1.47 mmol, i.e., a mole fraction of 0.5 mol%), with an NMR purity of 94 mol, is incorporated into 20 g of synthetic polyisoprene (containing 99.35% by weight of cis-1,4-isoprene units and 0.65% by weight of isoprene-3,4- units; Mn = 375,000 g / mol and lp = 3.6, measured according to the method described above) using a roller tool (external mixer at 30°C). The mixture is homogenized in 15 wallet passes. This mixing phase is followed by heat treatment (10 min at 80°C) under a press at 10 bar pressure. The 0.5% functional polymer A is obtained. 2-Ethyl imidazole (compound C) from Aldrich (0.144 g, 1.47 mmol, i.e., a mole fraction of 0.5% mol) is incorporated into 20.381 g of 0.5% functional polyisoprene A using a roller mill (external mixer at 30°C). The mixture is homogenized in 15 wallet passes.This mixing phase is followed by a heat treatment (10 min at 150°C) under a press at 10 bar pressure. The functional polymer A 0.5% - C 0.5% is obtained.

[0293] • Functional polyisoprene A 0.5% - C 0.5% - variant

[0294] The process is identical to that of polyisoprene A 0.5% - C 0.5% except that the duration of the heat treatment at 150°C under a press at 10 bars of pressure after the addition of compound C is 20 min.

[0295] Rubber compositions

[0296] The rubber compositions are manufactured according to the protocol described in section 4). Their quantitative composition is the same as that of the first series of tests (see section 5.1).

[0297] The rubber compositions obtained are respectively composition C5 and composition C6 for the variant.

[0298] 5.2.2. Process for preparing rubber compositions with a functional polymer (grafting of compound A in the external mixer without heat treatment and modification of the grafted polymer with compound C in the internal mixer) - variants 2

[0299] Functional polymer

[0300] 2-(glycidyloxy)-1-naphtonitrile oxide of 93% purity (381 mg, 1.47 mmol, i.e., a mol fraction of 0.5 mol%, compound A), of 93 mol% NMR purity, is incorporated into 20 g of synthetic polyisoprene (containing 99.35% by weight of cis-1,4-isoprene units and 0.65% by weight of isoprene-3,4-units; Mn = 375,000 g / mol and lp = 3.6, measured according to the method described above) using a roller tool (external mixer at 30°C). The mixture is homogenized in 15 wallet passes. There is no heat treatment under pressure; the 0.5% functional polyisoprene A is then used directly.

[0301] Rubber compositions In an internal mixer, filled to 70% and with an initial tank temperature of approximately 90°C, 20.38 g of functional polyisoprene A 0.5 obtained according to the above process, 2-ethyl imidazole (compound C) (0.144 g, 1.47 mmol i.e. a mole fraction of 0.5% mol), with silica (40 pc) with the silica coupling agent to the diene elastomer and finally, after one to two minutes of mixing, the second portion of silica (20 pc) and the various other ingredients are added, with the exception of the vulcanization system (sulfur and sulfenamide accelerator). A thermomechanical process (non-productive phase) is then carried out in one step (total mixing time of approximately 5 min), until a maximum "falling" temperature of approximately 160°C is reached.The mixture thus obtained is collected, allowed to cool, then the vulcanization system (sulfur and sulfenamide accelerator) is added to an external mixer (homo-finisher) at 70°C, mixing everything (productive phase) for about 5 to 6 min.

[0302] The rubber 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.

[0303] The calendered rubber compositions are then placed under a press at a temperature of 150°C for 30 min for their vulcanization.

[0304] Four compositions C7 to C10 are prepared differing by the conditions of addition of compound C (Table 3).

[0305] [Table 3]

[0306] Ingredients (2) to (10) are the same as those in test 1. Condition for adding compound C for compositions C7, C8, C9 and C10

[0307] The functional polyisoprene A 0.5% described previously is introduced into an internal mixer, whose initial tank temperature is about 90°C, followed by 2-ethyl imidazole (compound C) (0.144 g, 1.47 mmol, i.e., a mole fraction of 0.5% mol).

[0308] Compound C is introduced as shown in Table 4 below.

[0309] For composition C7, functional polyisoprene and compound C are added simultaneously.

[0310] For C8 to C10 rubber compositions, compound C is added 1 minute after the introduction of functional polyisoprene A 0.5%, with the internal mixer temperature differing.

[0311] [Table 4]

[0312] The first part of the silica is then introduced with the possible coupling agent and finally, after one to two minutes of mixing, the other part of the silica is introduced in proportions equal to the formulation C10, and the various other ingredients with the exception of the vulcanization system (sulfur and sulfenamide accelerator).

[0313] 5.2.3. Method of rubber with Internal functional and modification of the é with the treatment - Functional variant 3

[0314] 2-(glycidyloxy)-1-naphtonitrile oxide (compound A) (381 mg, 1.47 mmol, i.e., a mole fraction of 0.5 mol%), with an NMR purity of 93 mol⁻¹, is introduced into an internal mixer with an initial cell temperature of approximately 80°C. This mixture is then mixed with 20 g of synthetic polyisoprene (containing 99.35% by weight of cis-1,4-isoprene units and 0.65% by weight of isoprene-3,4-units; Mn = 375,000 g / mol and lp = 3.6, measured according to the method described above). The mixture is then subjected to thermomechanical processing in the same internal mixer at a temperature of 80°C for 1 min. This yields functional polyisoprene A 0.5%. Using an external roller mixer, 20.38 g of 0.5% functional polyisoprene A is mixed with 2-ethyl imidazole (compound C) from Aldrich (0.144 g, 1.47 mmol, i.e., a mole fraction of 0.5% mol). The mixture is homogenized in 15 wallet passes.This mixing phase is followed by a heat treatment at 150°C under a press at 10 bar pressure for 10 min to obtain the functionalized polyisoprene A 0.5% - C 0.5%.

[0315] C11 Rubber Composition

[0316] The C11 rubber composition (of the same composition as that of series 1) is obtained according to the process described in section 4.

[0317] 5.2.4. Process for preparing rubber compositions with a functional polymer (grafting of compound A in the internal mixer and modification of the grafted polymer with compound C in the internal mixer) - variants 4

[0318] Functional polyisoprene A 0.5% is manufactured as in paragraph 5.2.3.

[0319] 2-Ethylimidazole (compound C) (0.144 g, 1.47 mmol, i.e., a mole fraction of 0.5 mol%) is then introduced into an internal mixer with an initial tank temperature of approximately 80°C. A thermomechanical process is then carried out at the temperature and time specified in Table 5 below: [Table 5]

[0320] 3 compositions (C12 to C14) are prepared according to the conditions of addition of compound C (table 6).

[0321] Then, 40 parts per liter of silica are introduced, along with any coupling agent. Finally, after one to two minutes of mixing, the remaining 20 parts of silica and the various other ingredients are added, with the exception of the vulcanization system (sulfur and sulfenamide accelerator). A thermomechanical process (non-productive phase) is then carried out in a single step (total mixing time approximately 5 minutes) until a maximum "fall" temperature of approximately 160°C is reached. The resulting mixture is collected, cooled, and then the vulcanization system (sulfur and sulfenamide accelerator) is added to an external mixer (homo-finisher) at 70°C, mixing everything together (productive phase) for approximately 5 to 6 minutes.

[0322] The rubber 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.

[0323] The calendered rubber compositions are then placed under a press at a temperature of 150°C for 30 min for their vulcanization.

[0324] [Table 6]

[0325] Ingredients (2) to (10) are the same as those used in test 1.

[0326] 5.2.5. Results

[0327] The extensometry results at 23 °C for the C5 rubber composition (reference process) and the C6 to C14 rubber compositions are shown in Table 7. [Table 7] The results show that it is possible to obtain modified polymers that promote the dispersion of charges (for which the MA300 / MA100 ratio of the rubber composition is high) without causing excessive degradation of mechanical properties such as elongation at break and even allowing, where appropriate, for an increase in elongation at break.

[0328] Some processes can be advantageous from an industrial point of view by minimizing, for example, the number of steps (case of the C7 rubber composition for which the grafting of compound A is carried out in an external mixer without a heat treatment step) or by carrying out hot mixing operations at lower temperatures (case of the C7-C10 rubber compositions on the one hand and C12-C13 on the other).

Claims

DEMANDS 1. A process for preparing a modified polymer (III) comprising the following steps: (a) a step of grafting, onto a starting polymer comprising at least one unsaturation, a compound of formula (I) comprising an epoxide group, said grafting step comprising a step (a1) of mixing said polymer and said compound of formula (I) as follows: in which: Q represents a dipole comprising at least one nitrogen atom; A represents an arendiyl ring in C0-CM, possibly substituted by one or more hydrocarbon chains, identical or different, aliphatic, preferably saturated, linear or branched, possibly substituted or interrupted by one or more heteroatoms; E represents a divalent hydrocarbon group in C1-C20 possibly comprising one or more heteroatoms; Xi, X?, X3, identical or different, represent a hydrogen atom, an alkyl in CI-CO or an aryl in CO-CM; (b) a reaction step between the grafted polymer obtained at the end of step (a) and a compound of formula (II) to obtain the modified polymer (III), said reaction step comprising a mixing step (b1) of said grafted polymer and said compound of formula (II) as follows: in which Z, Y, R and R', identical or different, represent a hydrogen atom, an alkyl in CI-CO, a (CI-CO)alkyl-aryl in CO, OR an aryl in CO-CM, possibly comprising one or more heteroatoms, Y and Z being able to form together a ring, in particular aromatic, with the carbon atoms of the imidazole ring to which they are attached; the product obtained at the end of said process being a composition comprising the modified polymer (III), or the modified polymer (III) itself.

2. A process according to claim 1, wherein the starting polymer is an elastomer, preferably a diene elastomer.

3. A method according to claim 1 or claim 2 characterized in that the compound of formula (I) is selected from the compound of formula (Via) and the compound of formula (VIb) of the following formulas: in which: - a grouping chosen from R? to Ru of formula (la) and a grouping chosen from R? to R13 of formula (Ib) designates the group according to formula (V), such that: E is an -O-RM- group with RM a linear or branched C1-C10 alkyl group; Xi, X? and X3 are hydrogen atoms - the four other groups from R7 to Ru of formula (la) and the six other groups from R7 to R13 of formula (Ib) represent independently of each other, a hydrogen atom or a hydrocarbon chain, aliphatic, preferably saturated, linear or branched, possibly substituted or interrupted by one or more heteroatoms.

4. A process according to any one of the preceding claims, characterized in that compound (II) is selected from the group consisting of 1-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 1-benzyl-2-methylimidazole, 2-ethyl-4- methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1,2-dimethylimidazole and mixtures of these compounds.

5. A process according to any one of the preceding claims characterized in that the molar ratio of the compound of formula (I) relative to the starting polymer ranges from 0.1% to 0.6%, preferably from 0.2% to 0.5%, even more preferably from 0.2% to 0.4%.

6. A method according to any one of the preceding claims, characterized in that the ratio of the molar rate of the compound of formula (II) to the molar rate of the compound of formula (I) ranges from 20% to 125%, preferably from 40% to 120%, even more preferably from 50% to 120%.

7. A process according to any one of the preceding claims characterized in that steps a1) and b1) are carried out in bulk, and step a1) is carried out at a temperature below 40°C, and is followed by a step a2) of heat treatment under pressure or in an oven at temperatures from 40°C to 200°C, or step a) consists of step a1) carried out at a temperature above 60°C; and step b1) is carried out at a temperature below 40°C, and step b1) is followed by a step b2) of heat treatment under pressure or in an oven at temperatures from 40°C to 200°C, preferably from 80°C to 200°C, or step b) consists of step b1) carried out at a temperature above 60°C.

8. A process according to any one of claims 1 to 6 characterized in that steps a1) and b1) are carried out in bulk, and step a) consists of step a1) carried out at a temperature below 40°C; and step b1) is carried out at a temperature below 40°C, and is followed by a heat treatment step b2) under press or in oven at temperatures from 40°C to 200°C, preferably from 80°C to 200°C, or step b1) is carried out at a temperature above 60°C.

9. Composition obtainable according to the process of any one of claims 1 to 8, comprising a modified polymer (III), of formula (Ilia) if R'=H or (IIb) if R' is different from H: * representing the bond to the starting polymer, said bond being made up of the E, A groups, and the covalent bond resulting from the cycloaddition [3+2] of the Q group of the compound of formula (I) on at least one unsaturation of said polymer.

10. Modified polymer (III), of formula (Ilia) if R'=H or (lllb) if R' is different from H: * representing the bond to the starting polymer, said bond being made up of the E, A groups, and the covalent bond resulting from the cycloaddition [3+2] of the Q group of the compound of formula (I) on at least one unsaturation of said polymer, said polymer being capable of being obtained according to the process of any one of claims 1 to 8.

11. Rubber composition based on at least one reinforcing filler, a crosslinking system and at least: - a composition according to claim 9 or obtained according to the process of any one of claims 1 to 8; - and / or a modified polymer (III) according to claim 10 or obtained according to any one of claims 1 to 8.

12. Semi-finished article for pneumatic or non-pneumatic tire, said semi-finished article comprising a rubber composition according to claim 11.

13. Pneumatic or non-pneumatic bandage comprising at least one rubber composition according to claim 11 or a semi-finished article according to claim 12.

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