POLYMER GRAFT CARRYING FUNCTIONAL IMIDAZOLS PENDANT GROUPS

Abstract

The present invention relates to a process for preparing a modified polymer comprising functional pendant imidazole 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 reaction step between the grafted polymer obtained at the end of the previous step and a compound comprising an imidazole group.

Description

Title of the invention: Grafted polymer bearing functional pendant groups of imidazols FIELD OF INVENTION

[0001] 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, nitrogen and hydroxyl heterocycle functions, of their manufacturing processes and of their uses in compositions, in particular in rubber compositions intended especially for the manufacture of pneumatic or non-pneumatic tires. STATE OF THE ART

[0002] Ideally, a rubber compound intended for use in a pneumatic or non-pneumatic tire must meet a large number of technical requirements. One of these technical 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 designed to couple the rubber and the reinforcing filler, or functional elastomers into the rubber compound.

[0003] 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.

[0004] However, it is known that the improvement of one property of a rubber composition is achieved at the expense of another.

[0005] For example, those skilled in the art know that increasing the reinforcement of a rubber compound makes it more rigid. This increase in rigidity results in a decrease in its extensibility properties. If the extensibility properties decrease, the tire will be less resistant to physical stresses, thus exhibiting reduced durability and ultimately a shorter lifespan. Given the depletion of raw materials and energy resources, it is becoming increasingly important for manufacturers to offer pneumatic and non-pneumatic tires with a certain longevity, and therefore good durability.

[0006] 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 presents good extension properties.

[0007] 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.

[0008] We know from document WO2015059269A1 and WO2020249631A1 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.

[0009] In the past, it has also been discovered that the introduction of diene polymers, in particular elastomers, bearing at least one pendant epoxide group via the modification of a polymer having an unsaturation by a 1,3-dipolar compound having an epoxide group (WO2019102126A1, WO2019102128A1 and US20120046418A1) makes it possible to access rubber compositions having reinforcement properties maintained or improved compared to compositions not comprising functionalized polymers (WO2019102132A1, and WO2022 / 003278A1).

[0010] 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. Description of the invention

[0011] The applicant has thus developed a new process for the preparation of a modified polymer (III) comprising the following steps:

[0012] (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 (al) of mixing said polymer and said compound of formula (I) as follows: X2 / K X; ''O

[0013] in which:

[0014] - Q represents a dipole comprising at least one nitrogen atom;

[0015] - A represents a C6-Ci4 arenediyl ring, possibly substituted by a or several hydrocarbon chains, identical or different, aliphatic, of preferably saturated, linear or branched, possibly substituted or interrupted by one or more heteroatoms;

[0016] - E represents a divalent hydrocarbon group in Ci-C2O comprising possibly one or more heteroatoms;

[0017] - Xi, X2, X3, whether identical or different, represent a hydrogen atom, an alkyl in C1-C6 or an aryl in C6-C14;

[0018] (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 (bl) of said grafted polymer and said compound of the following formula (II): R Y.... i || j----R zx R Z

[0019] (II)

[0020] in which Z, Y, R and R1, identical or different, represent a hydrogen atom, a Ci-C6 alkyl, a (Ci-C6)alkyl-aryl in C6, or a C6-Ci4 aryl, 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.

[0021] Preferably, the starting polymer is an elastomer, more preferably a diene elastomer.

[0022] Preferably, the compound of formula (I) is chosen from the compound of formula (Via) and the compound of formula (Vlb) of the following formulas:

[0023] in which:

[0024] - a grouping chosen from R7 to Rn of the formula (la) and a grouping chosen among R7 to Rn of formula (Ib) denotes the group according to formula (V), (V): ...X xO

[0025] such that: E is an -O-Ru- group with R[4] a linear or branched Ci-Cio alkyl group; Xi, X2 and X3 are hydrogen atoms

[0026] - the four other groupings among R7 to Rn of formula (la) and the six other groups among R7 to Rn of formula (Ib) independently represent a hydrogen atom or an aliphatic hydrocarbon chain, 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, l-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) with respect to the starting polymer ranges 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 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%.

[0030] Preferably, steps a1) and b1) are carried out in bulk,

[0031] and step a1) is carried out at a temperature below 40°C, and it is followed by a step a2) of heat treatment under pressure or in an oven at temperatures ranging from 40°C to 200°C,

[0032] or

[0033] step a) consists of step al) carried out at a temperature above 60°C;

[0034] and step bl) is carried out at a temperature below 40°C, and step bl) is followed of a step b2) of heat treatment under pressure or in an oven at temperatures ranging from 40°C to 200°C, preferably from 80°C to 200°C,

[0035] or

[0036] step b) consists of step bl) carried out at a temperature above 60°C.

[0037] Preferably, steps a1) and b1) are carried out in bulk,

[0038] and step a) consists of step a1) carried out at a temperature below 40°C,

[0039] and step b1) is carried out at a temperature below 40°C, and it is followed by a step b2) of heat treatment under pressure or in an oven at temperatures ranging from 40°C to 200°C, preferably from 80°C to 200°C, or step bl) is carried out at a temperature above 60°C.

[0040] 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 (Illb) if R' is different from H:

[0041] (Ilia) to K

[0042] (Illb)

[0043] * representing the bond to the starting polymer, said bond being constituted of the E, A groups, and of 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.

[0044] Another object of the invention relates to a modified polymer (III), of formula (Ilia) if R'=H or (Illb) if R' is different from H:

[0045] (Ilia)

[0046] (Illb)

[0047] * representing the bond to the starting polymer, said bond being constituted of groups E, A, and of the covalent bond resulting from the cycloaddition [3+2] of the Q group of the compound of formula (I) onto at least one unsaturation of said polymer,

[0048] said polymer being capable of being obtained according to the process as described above.

[0049] The invention also relates to a rubber composition based on at least one reinforcing filler, a crosslinking system and at least:

[0050] - a composition as described above or obtained according to the process such as described above;

[0051] - and / or a modified polymer (III) as described above or obtained according to the process as described above.

[0052] Another object of the invention relates to a semi-finished article for pneumatic or non-pneumatic tire, said semi-finished article comprising a rubber composition as described above.

[0053] Another object of the invention relates to a pneumatic or non-pneumatic tire comprising at least one rubber composition as described above or a semi-finished article as described above.

[0054] Other aspects of the invention are as described below. DETAILED DESCRIPTION OF THE INVENTION Definitions

[0055] In this application, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0056] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​going from more than a to less than b (that is to say, bounds a and b excluded) while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​going from a to b (that is to say, including the strict bounds a and b).

[0057] The invention therefore relates to a process for the preparation of a modified polymer (III) comprising the following steps:

[0058] (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 (al) of mixing said polymer and said compound of formula (I) as follows: .¾ (I) Q„ J' XL '0

[0059] in which:

[0060] - Q represents a dipole comprising at least one nitrogen atom;

[0061] - A represents a C6-Ci4 arenediyl ring, possibly substituted by a or several hydrocarbon chains, identical or different, aliphatic, preferably saturated, linear or branched, possibly substituted or interrupted by one or more heteroatoms;

[0062] - E represents a divalent hydrocarbon group in Ci-C2O comprising possibly one or more heteroatoms;

[0063] - Xi, X2, X3, whether identical or different, represent a hydrogen atom, an alkyl in C1-C6 or an aryl in C6-C14;

[0064] (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 (bl) of said grafted polymer and said compound of the following formula (II): R' HAS Y x [| ------R Z"

[0065] (II)

[0066] in which Z, Y, R and R1, identical or different, represent a hydrogen atom, a Ci-C6 alkyl, a C6 (Ci-C6)alkyl-aryl or a C6-Ci4 aryl, 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. Polymer

[0067] By "grafted or graft-modified polymer" is meant a polymer having functional groups that have been introduced into the polymer chain after its polymerization. In practice, the 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 attachment, by a covalent bond, of the compound of formula (I) to unsaturations in the polymer chain.

[0068] The subsequent modification of the grafted polymer by covalent bonding of the compound of formula (II) leads to obtaining the modified polymer.

[0069] As is known, a polymer generally comprises at least one main polymer chain. This polymer chain can be described as main when all other chains of the polymer are considered to be pendant chains as mentioned in the document "Glossary of basic terms in polymer science" (IUP AC recommendations 1996), PAC, 1996, 68, 2287, p2294.

[0070] By "unsaturation" we mean a multiple covalent bond between two carbon atoms; this multiple covalent bond may be a carbon-carbon double bond or a carbon-carbon triple bond, preferably a carbon-carbon double bond.

[0071] 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 comprising 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.

[0072] 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.

[0073] More preferably, the initial polymer is an elastomer, preferably a diene elastomer.

[0074] By "diene" elastomer (or indistinctly rubber), whether natural or synthetic, is to 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).

[0075] These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". Generally, "essentially unsaturated" means 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 copolymers of dienes and alpha-olefins of the EPDM type do not fall within the previous definition and can in particular be described as "essentially saturated" diene elastomers (low or very low rate of motifs of diene origin, always less than 15%).

[0076] The term diene elastomer that can be used in the context of the present invention is particularly understood to mean:

[0077] - any homopolymer of a diene monomer, conjugated or not, having from 4 to 18 atoms of carbon;

[0078] - any copolymer of a diene, conjugated or not, having from 4 to 18 carbon atoms and of at least one other monomer.

[0079] The other monomer may be ethylene, an olefin or a diene, conjugated or not.

[0080] Suitable conjugated dienes are those having from 4 to 12 atoms of carbon, in particular 1,3-dienes, such as 1,3-butadiene and isoprene.

[0081] As unconjugated dienes, unconjugated dienes having 6 to 12 carbon atoms, such as 1,4-hexadiene, ethylidene norbomene, dicyclopentadiene.

[0082] Suitable olefins are vinylaromatic compounds having 8 to 20 carbon atoms and aliphatic α-monoolefins having 3 to 12 carbon atoms.

[0083] Suitable examples of vinylaromatic compounds include styrene, ortho-, meta-, para-methylstyrene, the commercial "vinyl-toluene" mixture, para-tert-butylstyrene.

[0084] As aliphatic α-monoolefins, acyclic aliphatic α-monoolefins having from 3 to 18 carbon atoms are particularly suitable.

[0085] More specifically, the diene elastomer is:

[0086] - 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;

[0087] - any copolymer obtained by copolymerization of one or more conjugated dienes between themselves or with one or more vinylaromatic compounds having 8 to 20 carbon atoms;

[0088] - a copolymer of isobutene and isoprene (butyl rubber), as well as versions halogenated, particularly chlorinated or brominated, of this type of copolymer.

[0089] - any copolymer obtained by copolymerization of one or more conjugated dienes or not, with ethylene, an α-monoolefin or their mixture such as for example elastomers obtained from ethylene, propylene with an unconjugated diene monomer of the aforementioned type.

[0090] 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.

[0091] 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 - IIR), isoprene-styrene copolymers (SIR) and mixtures of these elastomers.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] According to the invention, the initial polymer, preferably the elastomer, more preferably the diene elastomer, having an unsaturation, of

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102] preferentially a carbon-carbon double bond, is modified by grafting a compound of formula (I) as defined above also called a functionalizing agent. Step a) Compound of formula (I) According to formula (I), this functionalizing agent contains a group O designating a dipole comprising at least one nitrogen atom. For the purposes of this invention, "dipole" means a function capable of forming a 1,3 dipole addition on an unsaturated carbon-carbon bond. Preferably, the dipole comprising at least one nitrogen atom is chosen from the group consisting of nitrile oxide, nitrone and nitrile imine. Nitrile oxide, in the context of the present invention, means a dipole corresponding to the formula -C=N—>0, including its mesomeric forms. Nitrile imine, in the context of the present invention, means a dipole corresponding to the formula -C=N—>0, including its mesomeric forms. For the purposes of this invention, nitrone means a dipole corresponding to the formula -C=N(—>O)-, including its mesomeric forms. More preferably, group Q is a group of formula (IVa), (IVb) or (IVc), preferably of formula (IVb), * q - (IVb) *---— N --- (IVc) (IVa) in which:

[0103]

[0104]

[0105]

[0106]

[0107] - the symbol * represents the connection of Q to A; and - R4, R5 and R6 are chosen independently from a hydrogen atom, an alkyl, linear or branched, 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. A "hydrocarbon chain" is defined as 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 consist of 1 to 24 carbon atoms. Preferably R4, R5 and R6 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. . Even more preferably, R4, R5 and R6 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-C6, an aryl in C6-C20 possibly substituted by an alkyl, linear or branched, in Ci-C6.

[0108] According to formula (I), group A represents a C6-Ci4 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.

[0109] For the purposes of this invention, an "arendiyl ring" means 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.

[0110] By "monocyclic or polycyclic aromatic hydrocarbon group," we mean one or more aromatic rings whose skeleton is made up of carbon atoms. In other words, there are no heteroatoms in the ring's skeleton. 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 ortho-condensed or ortho- and peri-condensed. 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.

[0111] 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 have alkenyl or alkynyl functions 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.

[0112] Preferably, group A is a C6-Ci4 arenediyl ring, optionally substituted by one or more identical or different aliphatic hydrocarbon chain(s), saturated at C1-C24, optionally substituted or interrupted by one or more heteroatoms. More preferably still, group A is a C6-C arenediyl ring 14, possibly substituted by one or more alkyl group(s), identical or different, in C1-C12, (more preferably in Ci-C6, more preferably still in C1-C4) or substituted by an -O-R3 group in which R3 is an alkyl in CrC 12, preferably in Ci-C6, more preferably still in C1-C4.

[0113] Preferably, the compound of formula (I) is chosen from the following compounds of formula (la) and (Ib):

[0114] in which:

[0115] - the group Q is as defined above; preferably is chosen among the group consisting of nitrile oxide, nitrone and nitrile imine, more preferentially Q is nitrile oxide of formula (IVb);

[0116] - a grouping chosen from R7 to Rn of the formula (la) and a grouping chosen among R7 to R[3 of formula (Ib) denotes the group according to formula (V), x (V)

[0117] E, Xi, X2 and X3 being as described above,

[0118] - the four other groupings among R7 to Ru of the formula (la) and the six other groups among R7 to Rn of formula (Ib), identical or different, independently represent a hydrogen atom or an aliphatic hydrocarbon chain, preferably saturated, linear or branched, possibly substituted or interrupted by one or more heteroatoms.

[0119] 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).

[0120] Preferably, said hydrocarbon chain in the compounds of formula (la) and (ib) 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 an alkyl. in C1-C12 (more preferably in CrC6, more preferably still in CrC4) or a group chosen from -OR3, -NHR3, -SR3, R3 being an alkyl in C1-C12, more preferably in Ci-C6, more preferably still in C1-C4.

[0121] According to a preferred embodiment of the invention, in formula (la), R8 represents an E-epoxide group according to formula (V), and R7, R9, Rio, and Rn, 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, R8 represents an E-epoxide group according to formula (V), and R7, R9, Rio, and Ru, identical or different, represent a hydrogen atom or a C1-C12 alkyl (more preferably C1-C6, more preferably C1-C4) or a group selected from -OR3, -NHR3, -SR3, R3 being a C1-C12 alkyl, more preferably C1-C6, more preferably C1-C4.

[0122] More preferably in this embodiment, R8 represents an E-epoxide group according to formula (V), Rio represents a hydrogen atom, and R7, R9, and Ru represent a linear or branched hydrocarbon chain, preferably saturated at C1-C24, optionally substituted or interrupted by one or more heteroatoms. More preferably, R8 represents an E-epoxide group according to formula (V), Rio represents a hydrogen atom, and R7, R9, and Ru represent a C1-C12 alkyl, more preferably a C1-C6 alkyl, more preferably a C1-C4 alkyl, or a group selected from -OR3, -NHR3, -SR3, R3 being a C1-C12 alkyl, more preferably a C1-C6 alkyl, more preferably a C1-C4 alkyl.

[0123] According to another preferred embodiment of the invention, in formula (a), R9 represents an E-epoxide group according to formula (V), and R7, R8, Rio, and Rn, 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, R8, Rio, and Rn, identical or different, represent a hydrogen atom or a C1-C12 alkyl group (more preferably C1-C6, more preferably C1-C4) or a group selected from -OR3, -NHR3, -SR3, R3 being a C1-C12 alkyl group, more preferably C1-C6, more preferably C1-C4.

[0124] More preferably in this embodiment, R9 represents an E-group epoxide group according to formula (V), R7, R8 and Rn represent a hydrogen atom and R1 represents a linear or branched hydrocarbon chain of preferably saturated in C1-C24, possibly substituted or interrupted by one or more heteroatoms. More preferably still, R8 represents a group of formula E, an epoxide group according to formula (V), R7, R8 and Ru represent a hydrogen atom and Rio represents an alkyl in C1-C12, more preferably in Ci-C6, more preferably in CrC4 or a group chosen from -OR3, -NHR3, -SR3, R3 being an alkyl in C1-C12, more preferably in Ci-C6, more preferably in C1-C4.

[0125] According to another preferred embodiment of the invention, in formula (Ib), R7 represents an E-epoxide group according to formula (V) and R8 to R[3, 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, R7 represents an E-epoxide group according to formula (V) and R8 to R[3, identical or different, represent a hydrogen atom or a C1-C12 alkyl (more preferably CrC6, more preferably Ci-C4) or a group selected from -OR3, -NHR3, -SR3, R3 being a C1-C12 alkyl, more preferably Ci-C6, more preferably C1-C4.More preferably in this embodiment, R7 represents a group of epoxide groups of formula E-group according to formula (V) and R8 to R[3, identical, represent a hydrogen atom. .

[0126] 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 being 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.

[0127] Preferably, in compounds of formula (I), (la) and (Ib), the E group is a linear or branched hydrocarbon chain, preferably saturated in Ci-C20, more preferably in C1-C10, even more preferably in Ci-C6, optionally interrupted by one or more nitrogen, sulfur or oxygen atoms.

[0128] Preferably, in compounds of formula (I), (la) and (Ib), the E group is selected from the group consisting of -Ru-, -NH-Ru-, -O-Ru- and -S-Ru- with Ru a linear or branched diyl alkane in C1-C20, preferably in C1-C10, plus preferentially in Ci-C6. More preferably still, in compounds of formula (I), (la) and (Ib), the E group is chosen from the group consisting of -Ru- and -O-R14- with Ru a linear or branched diyl alkane in CrC2o, preferably in CrCio, more preferably in Ci-C6.

[0129] More preferably still, in the compounds of formula (I), (la) and (Ib), the E group is chosen from -(CH2)n- with n=l,2,3,4,5,6,7,8,9 or 10 and -O-(CH2)nn=l,2,3,4,5,6,7,8,9 or 10.

[0130] According to the compounds of formula (I), (la) and (Ib), the Xb X2, X3 groups of the epoxide group are identical or different, represent a hydrogen atom, a Ci-C6 alkyl or a C6-Ci4 aryl.

[0131] More preferably still, Xb X2 and X3, being identical, are a hydrogen atom.

[0132] Preferably, among the compounds of formula (la) and (Ib), the compound of formula (Via) and the compound of formula (VIb) are respectively preferred:

[0133] in which:

[0134] - a grouping chosen from R7 to Rn of the formula (la) and a grouping chosen among R7 to R[3 of formula (Ib) denotes the group according to formula (V),

[0135] such that: E is an -O-Ri4- group with R[4] a linear or branched Ci-Cio diyl alkane; Xi, X2 and X3 are hydrogen atoms,

[0136] - the four other groupings among R7 to Rn of formula (la) and the six other groupings among R7 to Rn of formula (Ib) are such as described above.

[0137] Preferably, the compounds (Via) are such that the group R8 designates the group of formula E-epoxide group according to formula (V), Rio represents a hydrogen atom and R7, R9 and Rn represent a C1-C4 alkyl.

[0138] Preferably, the compounds (Via) are such that the group R9 designates the group of formula E-epoxide group according to formula (V), R7, R8 and Rn represent a hydrogen atom and R10 represents a -OR3 group, R3 being an alkyl CrC4.

[0139] Preferably, the compounds (VIb) are such that R7 denotes the E-formula group epoxide according to formula (V) and R8 to Rn, identical, represent a hydrogen atom.

[0140] More preferably, the compound of formula (I) is chosen from among the compounds of formula (Via) and (VIb), more particularly is chosen from the group consisting of the compounds:

[0141] (Life)

[0142] (VId)

[0143] (Life)

[0144] (Vivacious)

[0145] Compounds of formula (I) can in particular be synthesized according to the processes described in WO2019102131A1, US20120046418Al, WO2022003278 and WO2023117844A1. Grafting#:

[0146] 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 (al) of mixing said polymer and said compound of formula (I).

[0147] The grafting is carried out by cycloaddition [3+2] of the Q group of the compound of formula (I) on said unsaturation.

[0148] The mechanism of this cycloaddition is illustrated in particular in document WO2015059269A1 pages 7 and 8.

[0149] Advantageously, the molar ratio of the compound of formula (I) with respect 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%.

[0150] 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.

[0151] When the molar rate is less than 0.1%, a limited impact of the polymer modification on the mechanical properties of rubber compositions comprising reinforcing fillers is observed.

[0152] When the molar ratio value is too high, the strengthening properties are no longer optimal and the mechanical properties, in particular the elongation at break and the stress at break, are degraded.

[0153] Step (al) is a mixing step of said polymer and said compound of formula (I).

[0154] 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 in an external mixer such as a roller mixer. Preferably, step (a1a) is carried out in bulk.

[0155] Advantageously, step a1) is carried out in bulk, in an extruder, an internal mixer or in an external mixer.

[0156] Advantageously, 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 ranging from 40°C to 200°C

[0157] or

[0158] step a) consists of step al) carried out at a temperature above 60°C.

[0159]

[0160]

[0161]

[0162] 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 al) carried out at a temperature below 40°C. In this case, step a) does not include any further heat treatment. When grafting is carried out on a large scale, it is preferably done in the presence of an antioxidant. 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. Step b) 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 (bl) of said grafted polymer and said compound of formula (II) as follows:

[0163]

[0164]

[0165]

[0166]

[0167]

[0168]

[0169] (II) in which Z, Y, R and R', identical or different, represent a hydrogen atom, a Ci-C6 alkyl, a C6 (Ci-C6)alkyl-aryl or a C6-Ci4 aryl, possibly including 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. Preferably, the compound of formula (II) may be 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. According to a preferred embodiment, Y and Z are a hydrogen atom. 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. R and R' can be identical and represent an alkyl in Ci-C6. R and R' can be different. In this case, R' can be a hydrogen atom and R an alkyl group in Ci-C6, preferably in Ci-C3.

[0170] Advantageously: - Y and Z are hydrogen atoms - R' is a hydrogen atom and R is an alkyl in Ci-C6, preferably in CrC3.

[0171] Advantageously, compound II is chosen from the following compounds (lia) and (Ilb):

[0172] (lia) H

[0173] (Ilb)

[0174] Compounds of formula (II), including compounds of formulas (lia) and (Ilb), are available from suppliers such as Sigma Aldrich, Evonik...

[0175] 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).

[0176] 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 compound of formula (I) incorporated in step a).

[0177] 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%.

[0178] This ratio corresponds to the ratio of the molar content of imidazole groups of the compound of formula (II) to the molar content of epoxide groups of the compound of formula (I) incorporated during step a), multiplied by 100.

[0179] 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.

[0180] In preferred ranges, modifying the polymer makes it possible to improve the tensile strength without changing the MA300 / MA100 parameter. The elongation at break can also be improved.

[0181] When the rate is greater than 125%, both the elongation at break and the stress at break are reduced.

[0182] Thus, compound (II) may be in slight excess relative to component (I). In this case, the modified polymer comprises nitrogenous and hydroxyl heterocyclic functions.

[0183] Otherwise, not all the epoxide functions react with compound (II) and the modified polymer then comprises epoxide, nitrogen heterocycle and hydroxyl functions.

[0184] Step (bl) is a mixing step of the grafted polymer obtained at the end of step a) and the compound of formula (II).

[0185] As with step a1) described above, 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.

[0186] Advantageously, step bl) is carried out in bulk, in an extruder, an internal mixer or in an external mixer.

[0187] Advantageously, 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 ranging from 40°C to 200°C, preferably from 80°C to 200°C, even more preferably between 100°C and 200°C,

[0188] or

[0189] step b) consists of step bl) carried out at a temperature above 60°C.

[0190] Advantageously, steps a1) and b1) are carried out in bulk, for example in an extruder, an external mixer or an internal mixer, and

[0191] step a1) is carried out at a temperature below 40°C, and it is followed by a step a2) of heat treatment under pressure or in an oven at temperatures ranging from 40°C to 200°C,

[0192] or

[0193] step a) consists of step al) carried out at a temperature above 60°C;

[0194] and

[0195] step b1) is carried out at a temperature below 40°C, and step b1) is followed by a heat treatment step b2) under pressure or in an 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,

[0196] or

[0197] and step b) consists of step bl) carried out at a temperature above 60°C.

[0198] Other variants of the implementation of steps a) and b) are possible.

[0199] Thus, according to one embodiment, steps a1) and b1) are carried out in bulk, by for example, in an extruder, an external mixer or an internal mixer

[0200] 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 step b2) of heat treatment under press or in 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.

[0201] This embodiment is advantageous from an industrial point of view since it allows minimizing the number of steps in the process.

[0202] When the modification in step b) is carried out in bulk, it is preferably carried out in the presence of an antioxidant.

[0203] 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.

[0204] According to another embodiment, step b) can be carried out in solution continuously or batchwise. The modified polymer thus obtained can be separated from its solution by any type of means known to those skilled in the art, and in particular by a steam stripping operation. Modified polymer (III)

[0205] The modified polymer (III) has the formula (Ilia) if R'=H or (Illb) if R' is different from H:

[0206] (Ilia)

[0207] (Illb)

[0208] * representing the bond to the starting polymer.

[0209] The groups Xb X2, X3, Y and Z are as described above.

[0210] The bond to the starting polymer consists of the E, A, and bond groups covalent resulting from the [3+2] cycloaddition of the Q group of the compound with formula (I) on at least one unsaturation of said polymer, the groups E, A and Q being as described above.

[0211] Advantageously, the starting polymer is an elastomer, preferably a diene elastomer as described above.

[0212] Advantageously, the molar ratio of the compound of formula (I) with respect 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%.

[0213] Only a fraction of the unsaturations of the initial polymer therefore reacts with the compound of formula (I).

[0214] Advantageously, 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%.

[0215] The modified polymer (III) comprises epoxide, nitrogen heterocycle and hydroxyl functions.

[0216] 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.

[0217] Composition comprising the modified polymer (III) or modified polymer (III) capable of being obtained according to the process described above

[0218] 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 (Illb) as described above.

[0219] The composition comprising 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.

[0220] This purification step can be carried out by any means known to a person skilled in the art, for example by filtration or washing.

[0221] In this case, the process according to the invention further comprises a step c) of purifying the composition obtained at the end of step b).

[0222] Another object of the invention relates to a modified polymer (III) of formula (Ilia) or (Illb) as described above and capable of being obtained according to the process described above. Rubber composition

[0223] Another object of the invention relates to a rubber composition based on at least one reinforcing filler, a crosslinking system and at least:

[0224] - a composition comprising a modified polymer (III), said composition being as described above or obtained according to the process described above;

[0225] - and / or a modified polymer (III) as described above or obtained according to the process as described above.

[0226] The rubber composition comprises any type of so-called reinforcing filler, known for its ability to strengthen a rubber composition usable for the manufacture of tires, for example an organic filler such as carbon black, an inorganic reinforcing filler such as silica combined with a known coupling agent, or a mixture of these two types of filler. Such a reinforcing filler typically consists of nanoparticles whose average size (by mass) is less than one micrometer, generally less than 500 nm, most often between 20 and 200 nm, and in particular and more preferably between 20 and 150 nm.

[0227] According to a particular embodiment of the invention, the reinforcing filler comprises an inorganic filler, preferably silica. According to 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 be the major component.

[0228] When combined with a major reinforcing inorganic filler such as silica, carbon black is preferably used at a concentration below 20 parts per cent (ppm), more preferably below 10 parts per cent (for example, between 0.5 and 20 ppm, particularly between 2 and 10 ppm). Within the indicated ranges, the coloring (black pigmenting agent) and UV-resistant properties of carbon black are utilized without compromising the typical performance provided by the reinforcing inorganic filler.

[0229] The term “reinforcing inorganic filler” herein means 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 any other means than an intermediate coupling agent, a rubber composition intended for the manufacture of tires. As is known, certain reinforcing inorganic fillers can be characterized, in particular, by the presence of hydroxyl groups (-OH) on their surface.

[0230] Mineral fillers of the siliceous type, preferably silica (SiO2) or of the aluminous type, in particular alumina (Al2O3), are suitable as reinforcing inorganic fillers.

[0231] The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenated silica.

[0232] Precipitated silica can be produced from non-renewable raw materials, in particular those derived from inorganic sand (silicon dioxide from inorganic sand), and from recycled materials such as foundry sands, end-of-life tires and in particular end-of-life tire treads consisting mainly of silica as a reinforcing filler or from bio-based raw materials such as organic waste from plants, preferably inedible organic waste from plants.

[0233] 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.

[0234] Among the plants having silicon dioxide in their tissues, we can mention mustard, grasses, maize, sugar cane bagasse, rice, wheat and in particular mustard husks, bamboo leaves, ears of maize, rice husks, wheat husks.

[0235] 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 precipitated silica.

[0236] 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...

[0237] In summary, the synthesis of a precipitation silica usable within the framework of the invention can be carried out from a sodium silicate entirely obtained 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.

[0238] 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 CT AB both less than 450 m2 / g, preferably within a range of 30 to 400 m2 / g, in particular 60 to 300 m2 / g.

[0239] Any type of precipitated silica can be used, in particular 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.

[0240] Examples include the silicas described in applications WO03 / 016215-A1 and WO03 / 016387-A1. Among the commercial HDS silicas, the following can be used in particular: “Ultrasil ® 5000GR”, “Ultrasil ® 7000GR” from Evonik, “Zeosil ® 1085GR”, “Zeosil® 1115 MP”, “Zeosil® 1165MP”, “Zeosil® Premium 200MP”, “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.

[0241] In the present exposition, the specific surface area BET is determined by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" (Vol. 60, page 309, February 1938), and more specifically according to a method adapted from the standard NF ISO 5794-1, Annex E of June 2010 [multipoint volumetric method (5 points) - gas: nitrogen - degassing under vacuum: one hour at 160°C - relative pressure range w / in: 0.05 to 0.17].

[0242] For inorganic fillers such as silica for example, the specific surface area values ​​CT AB were determined according to standard NF ISO 5794-1, Annex G of June 2010. The process is based on the adsorption of CTAB (N-hexadecyl-N,N,N-trimethylammonium bromide) on the "external" surface of the reinforcing filler.

[0243] 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 composition is insufficient to provide an adequate level of cohesion or wear resistance to the rubber component of the tire comprising this composition. 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.

[0244] To couple the reinforcing inorganic filler to the modified polymer, a coupling agent, in particular a silane (or bonding agent), at least bifunctional, is used in a well-known manner to ensure sufficient chemical and / or physical connection between the inorganic filler (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 particular 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 (notably disulfides, trisulfides or tetrasulfides) of bis-(alkoxyl(Ci-C4)-alkyl(Ci-C4)silyl-alkyl(CrC4)), such as bis(3-trimethoxysilylpropyl) or bis(3-triethoxysilylpropyl) polysulfides. Among these compounds, bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT, with the formula [(C2H5O)3Si(CH2)3S2]2, and bis-(triethoxysilylpropyl) disulfide, abbreviated TESPD, with the formula [(C2H5O)3Si(CH2)3S]2, are particularly useful.

[0245] The coupling agent content is advantageously less than 20 parts per cent, it being understood that it is generally desirable to use as little as possible. Typically, the coupling agent content is from 0.5% to 15% by weight relative to the amount of inorganic filler. Its content is preferably between 0.5% and 12 parts per cent, more preferably in 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 composition.

[0246] The rubber composition according to the invention may also contain, in addition to coupling agents, coupling activators, inorganic filler recovery agents or more generally, assisting agents implementation methods that are known to lower the viscosity of the compositions and improve their workability in the raw state.

[0247] The rubber composition according to the invention may also comprise all or part 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, for example, plasticizers or extending oils, pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents, reinforcing resins (such as resorcinol or bismaleimide), acceptors (for example, novolac phenolic resin) or methylene donors (for example, HMT or H3M) as described, for example, in application WO 02 / 10269

[0248] The crosslinking system may be any type of system known to those skilled in the art in the field of tire rubber compositions. It may, in particular, be sulfur-based, and / or peroxide-based, and / or bismaleimide-based. It may be polyacid-based, in particular diacid-based, as described in patent applications WO2014095582 and WO2014095585.

[0249] Preferably, the crosslinking system is sulfur-based; this is referred to as a vulcanization system. The sulfur can be supplied in any form, including molecular sulfur or a sulfur-donating agent. At least one vulcanization accelerator is also preferably present, and optionally, various known vulcanization activators such as zinc oxide, stearic acid, or equivalent compounds such as stearic acid salts and transition metal salts, guanidine derivatives (in particular diphenylguanidine), or known vulcanization retardants may be used.

[0250] Sulfur is used at a preferential rate of between 0.5 and 12 parts per annum, in particular between 1 and 10 parts per annum. The vulcanization accelerator is used at a preferential rate of between 0.5 and 10 parts per annum, more preferably between 0.5 and 5.0 parts per annum.

[0251] Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur may be used as an accelerator, in particular accelerators of the thiazole type and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types.

[0252] The rubber composition 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 phase mechanical working (the so-called "productive" phase) is carried out until a lower temperature, typically below 110°C, for example between 40°C and 100°C. This is the finishing phase during which the crosslinking system is incorporated. The rubber composition according to the invention can be either in its raw state (before crosslinking or vulcanization) or in its cured state (after crosslinking or vulcanization). Pneumatic

[0253] 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.

[0254] Semi-finished products for pneumatic or non-pneumatic tires are rubber products intended for the manufacture of pneumatic or non-pneumatic tires. This can be any type of rubber strip, such as, in particular, treads, crown reinforcement plies (for example, working plies, protective plies or reinforcing 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.

[0255] Preferably, the semi-finished article for pneumatic or non-pneumatic bandages is a tread.

[0256] As is known, the tread of a pneumatic or non-pneumatic tire comprises a rolling surface intended to be in contact with the ground when the pneumatic or non-pneumatic tire is in motion. The tread is provided with a tread pattern comprising, in particular, tread elements or elementary blocks delimited by various main grooves, longitudinal or circumferential, transverse or oblique, the elementary blocks possibly also comprising various finer incisions or slits.

[0257] The term "pneumatic tire" refers to a tire designed to form a cavity by cooperating with a supporting element, for example a rim, this cavity being capable of being pressurized to a pressure greater than atmospheric pressure. A pneumatic tire usually comprises two beads intended to come into contact with a rim, a crown consisting of at least one crown reinforcement and a tread, two sidewalls, the tire being reinforced by a carcass reinforcement anchored in the two beads.

[0258] By contrast, a "non-pneumatic tire" is a tire that supports the load of a vehicle by means other than pressurized inflation gas. Thus, a non-pneumatic tire is a toroidal body made of at least one polymeric material, intended 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 does not have the pneumatic rigidity provided by an inflation gas at a pressure higher than atmospheric pressure. A non-pneumatic tire usually comprises a base, designed, for example, for mounting on a rigid rim, a crown reinforcement, ensuring the connection to a tread, and a deformable structure, such as spokes, ribs, or dimples, this structure being arranged 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.

[0259] 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.

[0260] Non-pneumatic tires are intended to be fitted in particular to passenger vehicles or two-wheelers.

[0261] Preferably, the pneumatic tires according to the invention are intended to equip passenger vehicles.

[0262] The aforementioned features of the present invention, as well as others, will be better understood upon reading the following description of several examples of embodiments of the invention, given by way of illustration and not limitation. Examples 1. Methods

[0263] L1 Measurement of the number-average molar masses (Mn), weight-average molar masses (Mw) and the polydispersity index of elastomers

[0264] 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 being eluted 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.

[0265] Preparation of the elastomer sample to be tested

[0266] No special treatment 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. SEC analysis

[0267] The apparatus used is a WATERS alliance chromatograph. The elution 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".

[0268] 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 prepared using commercially available PSS READY CAL-KIT polystyrene standards.

[0269] 1.2 Characterization of compounds grafted onto diene elastomers

[0270] The molar content of compounds grafted onto diene elastomers is determined by NMR analysis. Spectra are acquired on a 500 MHz BRUKER spectrometer equipped with a CryoSonde BBFO-zgrad-5 mm. The quantitative 1H NMR experiment uses a single 30° pulse sequence and a 5-second repetition delay between each acquisition. The samples are solubilized in deuterated chloroform (CDC13) 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.

[0271] 2. Preparation of 2-(glycidyloxy)-l-naphtonitrile oxide (compound A) and of 2,4,6-Trimethyl-3-((2-methyl-l / - / -imidazol-l-yl)methyl)benzonitrile oxide (compound BL

[0272] 2-(glycidyloxy)-l-naphtonitrile oxide (compound A, CAS No. 1357580-85-8) was synthesized according to the procedure described in US patent application 20120046418 - see formula (Life)

[0273] (Life)

[0274] 2,4,6-trimethyl-3-((2-methyl-l / - / -imidazol-l-yl)methyl)benzonitrile oxide (compound B, case no. 1704606-51-8) was synthesized according to the procedure described in patent application WO2015059269. LMCN

[0275] (VII)

[0276] Compound C (ethyl-imidazole) of formula (Ilb) is also used. N H

[0277] (Ilb)

[0278] Compounds A and C are used in the process of manufacturing a modified polymer according to the invention.

[0279] Compound B is used in the manufacturing process of a modified polymer outside the invention. 3. Tests

[0280] The rubber compositions are characterized after baking, as indicated below. Traction tests

[0281] These tensile tests determine the breaking properties. Unless otherwise specified, they are carried out in accordance with French standard NF T 46-002 of September 1988.

[0282] The stresses at break (in MPa) and the elongations at break (in %) are measured at 23°C ± 2°C according to standard NF T 46-002.

[0283] The nominal secant modulus (or stress) is measured at the first elongation (i.e., after an accommodation cycle at the extension rate intended for the measurement itself). apparent, in MPa) at 100% elongation (noted MA 100) and at 300% elongation (noted MA300). 4. Preparation of rubber compositions

[0284] The following tests are carried out as follows: the modified or unmodified diene elastomer(s), the reinforcing filler(s), and any coupling agent are introduced into an internal mixer, filled to 70% 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 one 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.

[0285] The rubber compositions thus obtained are then calendered either in the form of plates (thickness of 2 to 3 mm) or thin sheets of rubber for the measurement of their physical or mechanical properties.

[0286] The test specimens are then placed under a press at a temperature of 150°C for 30 min. 5. Tests 5.1. Tests - Series 1

[0287] 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 (ethyl-imidazole). The polymers are named according to the compound(s) grafted and their grafting ratio.

[0288] 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%. Functional polymers

[0289] • functional polyisoprene A 0.3%#

[0290] 2-(glycidyloxy)-l-naphtonitrile oxide (compound A) of 93% purity (229 mg, 0.882 mmol, i.e., a mole fraction of 0.3 mol%), of 94 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 3,4-isoprene units; Mn = 375,000 g / mol and Ip = 3.6 measured according to the method described above) on a roller tool (external mixer at 30°C). The mixture is homogenized in 15 wallet passes. This phase of mixing is followed by heat treatment (10 min at 80°C) under a press at 10 bars of pressure. functional polyisoprene A 0.5%#

[0291] The process is identical to that of polyisoprene A 0.3% 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%#

[0292] The process is identical to that of polyisoprene A 0.3% except that compound A (763 mg, 2.94 mmol i.e. a mole fraction of 1% mol) is incorporated into the synthetic polyisoprene. Functional polyisoprene B 0.3%#

[0293] 2,4,6-Trimethyl-3-((2-methyl-l / - / -imidazol-l-yl)methyl)benzonitrile oxide (Compound B) of 94 mol% NMR purity (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 3,4-isoprene units; Mn = 375,000 g / mol and Ip = 3.6, measured according to the method described above) on a roller tool (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 120°C) under a press at 10 bars of pressure. composition comprising polyisoprene and compound C, denoted C 0.5%#

[0294] 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 Ip = 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 150°C) under a press at 10 bar pressure.

[0295] Compound C is not grafted onto polyisoprene. Functional polyisoprene A 0.3% - C 0.35%#

[0296] 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 tool (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. Functional polyisoprene A 0.3% - C 0.5%#

[0297] The process is identical to that of polyisoprene A 0.3% - C 0.35% except that 2-ethyl imidazole (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%#

[0298] 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. • Functional polyisoprene A 0.5% - C 0.35%#

[0299] 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%. • Functional polyisoprene A 0.5% - C 0.5%#

[0300] 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%. • Functional polyisoprene A 1% - C 0.5%#

[0301] 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 on a roller tool (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. Rubber compositions and results

[0302] Rubber compositions comprising the polymers were prepared as previously indicated in section 4, some of which conform to the invention (denoted Cx) and some not conforming (denoted NCx).

[0303] All rubber compositions have the same quantitative formulation, the quantities being expressed in parts by weight per hundred parts of elastomer (pce), i.e.: - 100 pce of functionalized or non-functionalized synthetic polyisoprene; - 3 pce of ASTM N234 grade carbon black (ASTM D1765-17) marketed by Cabot Corporation; - 60 pieces of silica "Zeosil 1165MP" marketed by Solvay; - 1 pc of antioxidant: 2,2,4-trimethyl-l,2-dihydroquinoline (TMQ) marketed by the company Flexys; - 5 pieces of paraffin - 1.5 pc of antioxidant: Nl,3-dimethylbutyl-N-phenyl-para- phenylenediamine marketed by Flexys under the reference "Santoflex 6-PPD"; - 6 pieces of a silica coupling agent to the diene elastomer: Bis[3- (triethoxysilyl)propyl] tetrasulfide silane (TESPT) marketed by Evonik under the reference "Si69"; - 2.5 pieces of stearic acid: stearin "Pristerene 4031" marketed by the company Uniquema; - 2.7 pieces of zinc oxide (industrial grade - Umicore company); - 1.65 pc of N-cyclohexyl-2-benzothiazyl-sulfenamide accelerator marketed by Flexys under the reference "Santocure CBS; - and 1.33 parts per annum of sulfur.

[0304] A reference rubber composition based on unfunctionalized polysiprene is used to compare the mechanical properties of the rubber compositions (results base 100).

[0305] The extensometry results at 23°C are shown in Tables 1 (rubber compositions outside the invention) and 2 (rubber compositions according to the invention).

[0306] [Tables 1] Composition T NCI NC2 NC3 NC4 NC5 Functionalized Polymer Non-functionalized A 0.3% A 0.5% A 1% B 0.3% C 0.5% Elongation at break at base 100 100 85 72 53 62 99 Average tensile strength at break at base 100 100 108 95 77 95 115 MA300 / MA100 at base 100 100 140 140 127 140 100

[0307] [Tables2] Composition Cl C2 C3 C4 C5 Functionalized polymer A 0.3% -C 0.35% A 0.3% -C 0.5% A 0.5% C 0.2% A 0.5% -C 0.35% A 0.5% C 0.5% Elongation at break at base 100 84 70 73 66 76 Average breaking strength at the bottom: 100 113 101 101 98 104 MA300 / MA100 at the bottom: 100 140 140 140 133 136

[0308] The MA300 / MA100 parameter characterizes the strengthening properties induced by the modification of the polymer. The higher this parameter, the higher the strengthening properties, which is linked to a better interaction between the rubber and the fillers.

[0309] 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.

[0310] The results in Table 1 show that: - Increasing the grafting rate of compound A (bearing an epoxy group) is accompanied by a decrease in the elongation at break and the tensile strength of the rubber composition, - at the same grafting rate (0.3%), grafting 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 rubber compositions.

[0311] Comparison of 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 (carrying an epoxy group) - NCI composition, the modification of this polymer by compound C at a level of 0.35% (composition Cl) makes it possible to improve the breaking strength without modifying the MA300 / MA100 parameter or the elongation at break.

[0312] When the percentage of compound C is 0.5% (composition C2), the elongation at break and the stress at break are reduced. - compared to the rubber composition with the polymer grafted with 0.5% of compound A (bearing an epoxy group) - NC2 rubber composition, the modification of this polymer by compound C to A height of 0.2%, 0.35% or 0.5% (respective rubber compositions C3, C4 and C5) allows the breaking strength to be improved without significantly changing the MA300 / MA100 parameter and the elongation at break. 5.2. Tests - Series 2#:

[0313] In this second series of tests, the 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 in an external mixer or an internal mixer, and the modification of the grafted polymer with compound C is carried out in an external mixer or an internal mixer.

[0314] 5.2.1. Process for preparing rubber compositions with polymer functional (grafting of compound A in the external mixer with heat treatment and modification of the grafted polymer with compound C in the external mixer with heat treatment of variable duration) - variant 1 Functional polymers

[0315] • Functional polyisoprene A 0.5% - C 0.5% according to the process described in the section 5.1. (reference)#

[0316] 2-(glycidyloxy)-l-naphtonitrile oxide (compound A) of 93% purity (381 mg, 1.47 mmol, i.e., a mole fraction of 0.5 mol%), of 94 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 Ip = 3.6, measured according to the method described above) on a roller tool (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 80°C) under a press at 10 bar pressure. The 0.5% functional polymer A is obtained.

[0317] 2-Ethylimidazole (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 functional polyisoprene A 0.5% 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 resulting functional polymer A 0.5% - C 0.5% is obtained. • Functional polyisoprene A 0.5% - C 0.5% - variant#

[0318] The process is identical to that of polysisoprene A 0.5% - C 0.5% except that the duration of the heat treatment at 150°C under a press at 10 bar pressure after the addition of compound C is 20 min. Rubber compositions

[0319] 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.L).

[0320] The rubber compositions obtained are respectively composition C5 and composition C6 for the variant.

[0321] 5.2.2. Process for preparing rubber compositions with polymer functional (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 Functional polymer

[0322] 2-(glycidyloxy)-l-naphtonitrile oxide of 93% purity (381 mg, 1.47 mmol, i.e., a mole 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 3,4-isoprene units; Mn = 375,000 g / mol and Ip = 3.6, measured according to the method described above) on 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. Rubber compositions

[0323] 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 are introduced 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 approximately 5 to 6 minutes.

[0324] The rubber compositions thus obtained are then calendered either in the form of plates (thickness of 2 to 3 mm) or thin sheets of rubber for the measurement of their physical or mechanical properties.

[0325] The calendered rubber compositions are then placed under a press at a temperature of 150°C for 30 min for their vulcanization.

[0326] 4 C7 to C10 compositions are prepared differing in the conditions of addition of the compound C (Table 3).

[0327] [Tables3] Composition C7 C8 C9 CIO functional polyisoprene N 99.29 99.29 99.29 99.29 2-ethyl imidazole (compound C) 0.71 0.71 0.71 0.71 Carbon black (2) 3.00 3.00 3.00 3.00 Silica (3) 60.00 60.00 60.00 60.00 TMQ (4) 1.00 1.00 1.00 1.00 WAX (5) 1.00 1.00 1.00 1.00 antioxidant (6) 1.50 1.50 1.50 1.50 coupling agent (7) 6.00 6.00 6.00 6.00 Stearic acid (8) 2.50 2.50 2.50 2.50 ZnO (9) 2.70 2.70 2.70 2.70 Accelerator (10) 1.65 1.65 1.65 1.65 Sulfur 1.33 1.33 1.33 1.33 CABCD compound addition condition

[0328] Ingredients (2) to (10) are the same as those in test 1.

[0329] Condition for adding compound C for compositions C7, C8, C9 and C10

[0330] In an internal mixer, the initial tank temperature of which is approximately 90°C, the functional polyisoprene A 0.5% described previously is introduced, followed by 2-ethyl imidazole (compound C) (0.144 g, 1.47 mmol i.e. a mole fraction of 0.5% mol).

[0331] Compound C is introduced as shown in Table 4 below.

[0332] For composition C7, functional polyisoprene and compound C are added simultaneously.

[0333] For C8 to CIO rubber compositions, compound C is added 1 minute after the introduction of functional polyisoprene A 0.5%, the internal mixer temperature differing.

[0334] [Tables4] Time (min) between the introduction of functional polyisoprene A 0.5% and the compound eC Temperature (°C) Condition A 0 90 Condition B 1 100 Condition C 1 120 Condition D 1 150

[0335] 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 CIO formulation, and the various other ingredients with the exception of the vulcanization system (sulfur and sulfenamide accelerator).

[0336] 5.2,3. Process for preparing rubber compositions with polymer functional (grafting of compound A in the internal mixer and modification of the grafted polymer with compound C in the external mixer with heat treatment) - variant 3 Functional polymer

[0337] 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, along with 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 Ip = 3.6, measured according to the method described above). Thermomechanical work is then carried out in this internal mixer at a temperature of 80°C for 1 min. The 0.5% functional polyisoprene A is obtained.

[0338] 2-ethylimidazole (compound C) from Aldrich (0.144 g, 1.47 mmol, i.e., a mole fraction of 0.5 mol%) is incorporated into an external roller-type mixer at 20.38 g of functional polyisoprene A 0.5%. 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 functionalized polyisoprene A 0.5% - C 0.5%. Rubber composition Cil

[0339] The Cil rubber composition (of the same composition as that of series 1) is obtained according to the process described in section 4.

[0340] 5.2,4. Process for preparing rubber compositions with polymer functional (grafting of compound A in the internal mixer and modification of the grafted polymer with compound C in the internal mixer) - variants 4

[0341] Functional polyisoprene A 0.5% is manufactured as in paragraph 5.2.3.

[0342] It is then introduced into an internal mixer, the initial temperature of which is is approximately 80°C, 2-ethylimidazole (compound C) (0.144 g, 1.47 mmol, i.e., a (mole fraction of 0.5% mol). Thermomechanical work is then carried out at a temperature and time specified in the following Table 5:

[0343] [Tables5] Thermomechanical working time (min) Temperature (°C) Condition A1 1 80 Condition A2 1 120 Condition A3 1 150

[0344] 3 compositions (C12 to C14) are prepared according to the conditions of addition of the compound C (table 6).

[0345] Then, 40 parts per liter of silica are introduced, along with any coupling agent, and finally, after one to two minutes of mixing, the remaining 20 parts of silica and the various other ingredients, with the exception of the vulcanization system (sulfur and sulfenamide accelerator), are 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.

[0346] The rubber compositions thus obtained are then calendered either in the form of plates (thickness of 2 to 3 mm) or thin sheets of rubber for the measurement of their physical or mechanical properties.

[0347] The calendered rubber compositions are then placed under a press at a temperature of 150°C for 30 min for their vulcanization.

[0348] [Tableauxô] Composition C12 C13 C14 Functional Polyisoprene O 99.29 99.29 99.29 2-Ethylimidazole (Compound C) 0.71 0.71 0.71 Carbon Black (2) 3.00 3.00 3.00 Silica (3) 60.00 60.00 60.00 TMQ (4) 1.00 1.00 1.00 WAX (5) 1.00 1.00 1.00 Antioxidant (6) 1.50 1.50 1.50 Coupling Agent (7) 6.00 6.00 6.00 Stearic Acid (8) 2.50 2.50 2.50 ZnO (9) 2.70 2.70 2.70 Accelerator (10) 1.65 1.65 1.65 Sulfur 1.33 1.33 1.33 Condition for adding compound C Al A2 A3

[0349] Ingredients (2) to (10) are the same as those used in test 1. 5.2.5. Results

[0350] 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.

[0351] [Tables?] Composition C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 Variant Process Reference Section 5.2.1. Variant 1 Section 5.2.1 Variants 2 Section 5.2.2. Variant 3 Section 5.2.3. Variants 4 Section 5.2.4. Elongation at break at base 100 76 83 81 80 72 79 76 85 87 79 Average breaking stress at base 100 104 103 107 111 102 108 105 107 109 104 MSA300 / MSA100 at base 100 136 133 153 140 147 153 147 133 133 147

[0352] The results show that it is possible to obtain modified polymers promoting 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.

[0353] 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 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: X2 in which: - Q represents a dipole comprising at least one nitrogen atom; - A represents a C6-Ci4 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; - E represents a divalent hydrocarbon group in C1-C20 possibly comprising one or more heteroatoms; - Xi, X2, X3, whether identical or different, represent a hydrogen atom, a Ci-C6 alkyl or a C6-Ci4 aryl; (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: (II) in which Z, Y, R and R', identical or different, represent a hydrogen atom, a Ci-C6 alkyl, a C6 (Ci-C6)alkyl-aryl, or a C6-Ci4 aryl, possibly comprising one or more

2.

3. heteroatoms, Y and Z can together form 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. A process according to claim 1, wherein the starting polymer is an elastomer, preferably a diene elastomer. A method according to claim 1 or claim 2 characterized in that the compound of formula (I) is chosen from the compound of formula (Via) and the compound of formula (Vlb) of the following formulas: in which: - a grouping chosen from R7 to Ru of formula (la) and a grouping chosen from R7 to Rn of formula (Ib) designates the group according to formula (V), r x-(V) X^ such that: E is an -O-Ri4- group with Ru a linear or branched Ci-Ci0 alkyl; Xb, X2 and X3 are a hydrogen atom - the other four groups from R7 to Ru of formula (la) and the other six groups from R7 to Rn of formula (Ib) independently represent a hydrogen atom or an aliphatic hydrocarbon chain, 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, l-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 method 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 pressure or in

9. oven at temperatures ranging from 40°C to 200°C, preferably from 80°C to 200°C, or step bl) is carried out at a temperature above 60°C. 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 (Illb) if R' is different from H: (Ilia) &

10. (Illb) * 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. Modified polymer (III), of formula (Ilia) if R'=H or (Illb) if R' is different from H: (Ilia)

11.

12.

13. (Illb) * 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. 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. Semi-finished article for pneumatic or non-pneumatic tire, said semi-finished article comprising a rubber composition according to claim 11. Pneumatic or non-pneumatic bandage comprising at least one rubber composition according to claim 11 or a semi-finished article according to claim 12.