CN113227155A

CN113227155A - Rubber composition based on at least one compound bearing cyclic carbonate functions

Info

Publication number: CN113227155A
Application number: CN201980086381.0A
Authority: CN
Inventors: F·让-巴蒂斯特-迪特-多米尼克; A·雅斯琳
Original assignee: Compagnie Generale des Etablissements Michelin SCA
Current assignee: Compagnie Generale des Etablissements Michelin SCA
Priority date: 2018-12-27
Filing date: 2019-12-19
Publication date: 2021-08-06
Anticipated expiration: 2039-12-19
Also published as: CN113227155B; FR3091288B1; FR3091289A3; FR3091288A1; WO2020136332A1

Abstract

The invention relates to a rubber composition based on at least one diene elastomer, at least one reinforcing filler, at least one crosslinking agent and at least one compound of formula (I), optionally grafted to the elastomer; wherein: -Q is a dipole comprising at least one nitrogen atom; -A is an arenediyl ring, optionally substituted with one or more hydrocarbon chains, which may be the same or different and independent of each other, andoptionally substituted or interrupted by one or more heteroatoms; -E is a divalent hydrocarbon-based linking group which may optionally contain one or more heteroatoms; -R1, R2 and R3 represent, independently from each other, a hydrogen atom or a hydrocarbon chain, optionally substituted or interrupted by one or more heteroatoms; and-n is an integer having a value greater than or equal to 1. The invention also relates to a semi-finished tyre and a tyre comprising such a composition.

Description

Rubber composition based on at least one compound bearing cyclic carbonate functions

Technical Field

The present invention relates to a rubber composition, in particular intended for the manufacture of tyres, based on at least one diene elastomer, at least one reinforcing filler, at least one cross-linking agent and at least one specific compound bearing cyclic carbonate functions. The application also relates to a process for preparing such a composition, to a semi-finished product for tyres and to a tyre comprising such a rubber composition.

Background

In the industrial field, mixtures of polymers and fillers are generally used. In order for such mixtures to exhibit good properties, methods for improving the dispersibility of the filler in the polymer are constantly being sought.

In particular with respect to rubber compositions intended for the manufacture of tires, manufacturers are always looking for rubber compositions comprising fillers having good mechanical properties, such as reinforcement and as low hysteresis as possible (equivalent to low rolling resistance).

It is known that, in general, in order to obtain the best reinforcing properties imparted by reinforcing fillers, it is desirable to have said reinforcing fillers present in the elastomeric matrix in a final form which is as finely divided as possible and distributed as homogeneously as possible. In fact, such conditions can only be achieved when the reinforcing filler has the excellent ability, on the one hand, to be incorporated into the elastomeric matrix and to deagglomerate during mixing with the elastomer, and, on the other hand, to be homogeneously dispersed in this matrix.

In a well-known manner, carbon black exhibits this capability, which inorganic fillers do not normally possess. This is because, for reasons of mutual affinity, the inorganic filler particles have an undesirable tendency to agglomerate together in the elastomer matrix. If virtually all (reinforcing filler/elastomer) bonds that can be generated during the mixing operation are obtained, these interactions have the detrimental consequence of limiting the dispersion of the filler and therefore the reinforcing properties to levels substantially lower than theoretically possible.

In order to achieve a good dispersion of the reinforcing filler in the rubber composition and to obtain a rubber composition exhibiting good reinforcing properties and reduced hysteresis, various solutions have been experimented.

Mention may in particular be made of the use in the rubber compositions of polymers having a structure modified at the end of the polymerization by a functionalizing agent, a coupling agent or a star branching agent, with the aim of obtaining a good interaction between the polymer thus modified and the reinforcing filler, whether it be carbon black or a reinforcing inorganic filler. Mention may be made, for example, of diene elastomers comprising functional groups containing a carbon-tin bond, aminated functional groups (for example aminobenzophenone) and silanol or polysiloxane functional groups having a silanol end.

In particular, document WO2018015646 discloses a rubber composition based on a terpolymer of styrene, butadiene and 4- (hydroxymethyl) -1, 3-dioxolan-2-one methacrylate, silica and a crosslinking system, the terpolymer carrying along its main chain pendant carbonate functions. The terpolymer is capable of better reinforcing a rubber composition comprising the terpolymer than a rubber composition based on an ungrafted SBR copolymer. The terpolymer is obtained by free radical polymerization.

However, there is still a continuing need for rubber compositions having improved properties compared to prior art rubber compositions.

Disclosure of Invention

This need is met by a rubber composition based on a diene elastomer, a reinforcing filler, at least one compound of a crosslinking system bearing cyclic carbonate functions and optionally having been grafted to said diene elastomer. These rubber compositions have better reinforcing properties and better hysteresis properties. Advantageously, the diene elastomer used in these compositions can have any type of microstructure.

The subject of the invention is therefore a rubber composition based on at least one diene elastomer, at least one reinforcing filler, at least one crosslinking agent and at least one compound of formula (I), optionally grafted to the diene elastomer

Wherein:

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

-a represents an arylenediyl ring, optionally substituted by one or more hydrocarbon chains, which may be identical or different and independent of each other, and optionally substituted or interrupted by one or more heteroatoms;

-E represents a divalent hydrocarbon binding group which may optionally comprise one or more heteroatoms;

-R₁、R₂and R₃Independently of one another, represents a hydrogen atom or a hydrocarbon chain, optionally substituted or interrupted by one or more heteroatoms; and

-n is an integer having a value greater than or equal to 1.

Another subject-matter of the invention is a process for preparing the rubber composition according to the invention.

Another subject-matter of the present invention is a semi-finished product for tyres comprising at least one rubber composition according to the invention.

Another subject of the invention is a tire comprising a rubber composition according to the invention.

Detailed Description

A first subject of the invention is a rubber composition based on at least one diene elastomer, at least one reinforcing filler, at least one crosslinking agent and at least one compound of formula (I), optionally grafted to the diene elastomer

Wherein:

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

-n is an integer having a value greater than or equal to 1.

In the present application, all percentages (%) shown are mass percentages (%), unless explicitly stated otherwise.

Furthermore, any numerical interval denoted by the expression "between a and b" denotes a range of values extending from more than a to less than b (i.e. limits a and b are not included), whereas any numerical interval denoted by the expression "from a to b" means a range of values extending from a up to b (i.e. strict limits a and b are included).

The carbon-containing compounds mentioned in the description may be of fossil or bio-based origin. In the case of a carbon-containing compound bio-based source, it may be partially or completely derived from biomass or obtained by renewable starting materials derived from biomass. In particular to polymers, plasticizers, fillers, and the like.

Within the meaning of the present application, the term "phr (acronym of french" pce ")" means parts by weight per hundred parts by weight of elastomer.

Within the meaning of the present invention, when referring to a "primary" compound, it is understood to mean that, among the same type of compounds of the composition, the compound is primary, i.e. the compound which makes up the greatest amount by mass among the compounds of the same type. Thus, for example, the predominant elastomer is the elastomer that has taken the greatest mass relative to the total mass of elastomers in the composition. In the same way, the "predominant" filler is the filler that makes up the greatest mass of the fillers in the composition. For example, in a system comprising only one elastomer, within the meaning of the present invention, the elastomer is predominant; and in a system comprising two elastomers, the predominant elastomer comprises more than half of the mass of the elastomer, preferably more than 51% by mass of the total mass of the elastomer.

The expression "composition based on" is understood to mean that the composition comprises a mixture and/or an in situ reaction product of the various components used, some of which are capable of (and/or intended to) at least partially react with each other during the various preparation stages of the composition; thus, the composition may be in a fully or partially crosslinked state or in an uncrosslinked state.

The rubber composition according to the invention comprises at least one compound of formula (I), optionally grafted to a diene elastomer.

According to formula (I), the compound comprises a group Q representing a dipole comprising at least one nitrogen atom.

Within the meaning of the present invention, "dipole" is understood to mean a functional group capable of carrying out a1, 3-dipolar addition on an unsaturated carbon-carbon bond.

Preferably, the dipole comprising at least one nitrogen atom is selected from the group consisting of nitrile oxides, nitrones and nitrilimines.

Within the meaning of the present invention, the term "nitrile oxide" is understood to mean the dipole corresponding to the formula C ≡ N → O (including its racemic form).

Within the meaning of the present invention, the term "nitrilimine" is understood to mean a dipole (including its endo-racemic form) corresponding to the formula C ≡ N → N.

Within the meaning of the present invention, the term "nitrone" is understood to mean a dipole (including its racemic form) corresponding to the formula-C ═ N (→ O).

Even more preferably, the group Q is a group of formula (II), (III) or (IV)

Wherein:

-symbol denotes the attachment of Q to a; and

-R₄、R₅and R₆Independently selected from hydrogen atoms, linear or branched C₁-C₂₀Alkyl, C optionally substituted by a hydrocarbon chain₃-C₃₀Cycloalkyl and C optionally substituted by a hydrocarbon chain₆-C₂₀And (4) an aryl group.

The term "hydrocarbon chain" is understood to mean 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 contain from 1 to 24 carbon atoms.

Preferably, R₄、R₅And R₆Independently selected from hydrogen atoms, linear or branched C₁-C₂₀Alkyl, optionally saturated C₁-C₂₄C substituted by hydrocarbon chain₃-C₃₀Cycloalkyl, and optionally saturated C₁-C₂₄C substituted by hydrocarbon chain₆-C₂₀And (4) an aryl group. Even more preferably, R₄、R₅And R₆Independently of one another, from hydrogen atoms, linear or branched C₁-C₂₀Alkyl, optionally linear or branched C₁-C₆Alkyl substituted C₃-C₃₀Cycloalkyl, and optionally linear or branched C₁-C₆Alkyl substituted C₆-C₂₀And (4) an aryl group.

According to formula (I), A represents an arylenediyl ring, optionally substituted by one or more hydrocarbon chains, which may be identical or different and are independent of one another, and optionally substituted or interrupted by one or more heteroatoms.

Within the meaning of the present invention, the term "arenediyl ring" is understood to mean a monocyclic or polycyclic aromatic hydrocarbon radical derived from an arene from which two hydrogen atoms have been removed. Thus, an arene bicyclic ring is a divalent group.

The term "monocyclic or polycyclic aromatic hydrocarbon radical" is understood to mean one or more aromatic rings whose skeleton is composed of carbon atoms. In other words, there are no heteroatoms in the backbone of the ring. The arenediyl ring can be monocyclic (i.e., consisting of a single ring) or polycyclic (i.e., consisting of multiple fused aromatic hydrocarbon rings); such fused rings then share at least two consecutive carbon atoms. These rings may be unilaterally fused or unilaterally and peri-fused. Preferably, the arene bicyclic ring comprises between 6 and 14 carbon atoms.

Preferably, when the arenediyl ring is substituted by one or more hydrocarbon chains, which are identical or different and independent of each other, and substituted or interrupted by one or more heteroatoms, the chain or chains are inert with respect to the cyclic carbonate function and with respect to the group Q.

Within the meaning of the present invention, the term "hydrocarbon chain which is inert with respect to the cyclic carbonate function and with respect to the group Q" is understood to mean a hydrocarbon chain which does not react with said cyclic carbonate function and with said group Q. Thus, the hydrocarbon chain that is inert with respect to the functional group and with respect to the group is, for example, a hydrocarbon chain that does not have any alkenyl or alkynyl functional group capable of reacting with the functional group or the group. Preferably, these hydrocarbon chains are saturated and may contain from 1 to 24 carbon atoms.

Preferably, the group A is C₆-C₁₄An arenediyl ring, optionally substituted with one or more hydrocarbon chains, which are the same or different and independent of each other, and optionally substituted or interrupted with one or more heteroatoms. More preferably, the group A is (preferably C)₆-C₁₄) An arenediyl ring, optionally saturated with one or more C's, the same or different₁-C₂₄A hydrocarbon chain, and optionally substituted or interrupted by one or more nitrogen, sulfur or oxygen heteroatoms. Even more preferably, the group A is C₆-C₁₄An arenediyl ring, optionally substituted by one or more identical or different C₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) The substitution of the alkyl group is carried out,OR by a group selected from-OR ', -NHR' and-SR ', R' being alkyl, preferably C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group.

Preferably, the compound of formula (I) is selected from compounds of the following formulae (Ia) and (Ib):

wherein:

-the group Q is as defined above; preferably it is selected from the group consisting of nitrile oxides, nitrones and nitrilimines, more preferably Q is a group of formula (III);

formula (Ia) is selected from R₇To R₁₁And formula (Ib) is selected from R₇To R₁₃Represents a group of the following formula (V):

wherein n, E and R₁、R₂And R₃As defined above, the above-mentioned,

-the other four radicals of formula (Ia) and the other six radicals of formula (Ib) are identical or different and represent, independently of each other, a hydrogen atom or a linear or branched, preferably saturated, hydrocarbon chain optionally substituted or interrupted by one or more heteroatoms.

Preferably, the hydrocarbon chain in the compounds of formulae (Ia) and (Ib) is inert with respect to the group of formula (V) and with respect to the group Q. Preferably, the hydrocarbon chain is saturated and may contain from 1 to 24 carbon atoms. Preferably, the hydrocarbon chain is C₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) Alkyl, OR a group selected from-OR ', -NHR' and-SR ', R' being C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group.

According to a preferred embodiment of the present invention,in formula (Ia), R₈Represents a radical of formula (V) as defined above, R₇、R₉、R₁₀And R₁₁Identical or different and represent a hydrogen atom or a linear or branched, preferably saturated, C optionally substituted or interrupted by one or more heteroatoms₁-C₂₄A hydrocarbon chain. More preferably, R₈Represents a radical of formula (V) as defined above, R₇、R₉、R₁₀And R₁₁Are the same or different and represent a hydrogen atom or C₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) Alkyl, OR a group selected from-OR ', -NHR' and-SR ', R' being C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group.

Even more preferably, in this embodiment, R₈Represents a radical of formula (V) as defined above, R₁₀Represents a hydrogen atom, R₇、R₉And R₁₁Denotes a linear or branched, preferably saturated, C optionally substituted or interrupted by one or more heteroatoms₁-C₂₄A hydrocarbon chain. Even more preferably, R₈Represents a radical of formula (V) as defined above, R₁₀Represents a hydrogen atom, R₇、R₉And R₁₁Is represented by C₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) Alkyl, OR a group selected from-OR ', -NHR' and-SR ', R' being C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group.

According to another preferred embodiment of the invention, in formula (Ib), R₇Represents a radical of formula (V) as defined above, R₈To R₁₃Identical or different and represent a hydrogen atom or a linear or branched, preferably saturated, C optionally substituted or interrupted by one or more heteroatoms₁-C₂₄A hydrocarbon chain. More preferably, R₇Represents a radical of formula (V) as defined above, R₈To R₁₃Are identical or different and represent a hydrogen atom orC₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) Alkyl, OR a group selected from-OR ', -NHR' and-SR ', R' being C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group. Even more preferably, in this embodiment, R₇Represents a radical of formula (V) as defined above, R₈To R₁₃The same, and represents a hydrogen atom.

According to the compounds of formulae (I), (Ia) and (Ib), the group E is a divalent hydrocarbon-binding group which may optionally contain one or more heteroatoms. Within the meaning of the present invention, the term "divalent hydrocarbon-binding group" is understood to mean a spacer group forming a bridge between the group A and the group of formula (V), the spacer group being a linear or branched, saturated or unsaturated (preferably saturated) C₁-C₂₄A hydrocarbon chain, which may optionally include one or more heteroatoms (e.g., N, O and S). The hydrocarbon chain may optionally be substituted as long as the substituent does not react with the group Q and the group of formula (V) as defined above.

Preferably, in the compounds of formulae (I), (Ia) and (Ib), the radical E is a linear or branched, preferably saturated, C₁-C₂₄More preferably C₁-C₁₀Even more preferably C₁-C₆A hydrocarbon chain, optionally interrupted by one or more nitrogen, sulfur or oxygen atoms.

Preferably, in the compounds of formula (I), (Ia) and (Ib), the group E is selected from the group consisting of-R-, -NH-R-, -O-R-and-S-R-, R being a linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkylene group.

Even more preferably, in the compounds of formulae (I), (Ia) and (Ib), the group E is selected from the group consisting of-R-and-O-R-, R being a linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkylene group.

Even more preferably, in the compounds of formulae (I), (Ia) and (Ib), the group E is selected from-CH₂-、-CH₂-CH₂-、-CH₂-CH₂-CH₂-、-CH₂-CH₂-CH₂-CH₂-、-O-CH₂-、-O-CH₂-CH₂-、-O-CH₂-CH₂-CH₂and-O-CH₂-CH₂-CH₂-CH₂-。

In the compounds of formulae (I), (Ia) and (Ib), n is an integer greater than or equal to 1, more preferably n is an integer having a value of 1,2, 3 or 4; more preferably, n is an integer having a value of 1 or 2, even more preferably n ═ 1.

In the compounds of the formulae (I), (Ia) and (Ib), R₁、R₂And R₃Independently of one another, represent a hydrogen atom or a hydrocarbon chain, optionally substituted or interrupted by one or more heteroatoms (for example N, O and S). More preferably, the group R₁、R₂And R₃Independently of one another, represents a hydrogen atom or a linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkyl group. Even more preferably, the group R₁Is a hydrogen atom, a radical R₂And R₃Identical or different and being linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkyl group. Even more preferably, R₁、R₂And R₃The same and are hydrogen atoms.

Preferably, among the compounds of formula (I), particular preference is given to compounds of formula (VI)

Wherein:

-a represents an arylenediyl ring, optionally substituted by one or more hydrocarbon chains, which are identical or different and independent of each other, and optionally substituted or interrupted by one or more heteroatoms;

-E represents a divalent hydrocarbon group which may optionally comprise one or more heteroatoms;

-n is an integer having a value greater than or equal to 1.

Preferably, in the compound of formula (VI), the group A is (preferably C)₆-C₁₄) An arenediyl ring optionally substituted by one or more identical or different, preferably saturated, C₁-C₂₄A hydrocarbon chain, and optionally substituted or interrupted with one or more heteroatoms (e.g., O, N and S). More preferably, the group A is C₆-C₁₄An arenediyl ring, optionally substituted by one or more identical or different C₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) Alkyl substituted OR substituted by a group selected from-OR ', -NHR' and-SR ', R' being C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group.

Even more preferably, among the compounds of formula (VI), particular preference is given to compounds of formulae (VIa) and (VIb)

Wherein:

-formula (VIa) is selected from R₇To R₁₁And formula (VIb) is selected from R₇To R₁₃Represents a group of the following formula (V):

wherein, n, E, R₁、R₂And R₃As defined above, the above-mentioned,

the other four radicals of formula (VIa) and the other six radicals of formula (VIb) being identical or different and, independently of one another, representing a hydrogen atom or a linear or branched, preferably saturated, radicalC₁-C₂₄A hydrocarbon chain, said hydrocarbon chain optionally substituted or interrupted by one or more heteroatoms. Preferably, the hydrocarbon chain in the compounds of formulae (VIa) and (VIb) is inert with respect to the group of formula (V) and with respect to the group Q. Preferably, the hydrocarbon chain is C₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) Alkyl, OR a group selected from-OR ', -NHR' and-SR ', R' being C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group.

Preferably, in the compounds of formulae (VI), (VIa) and (VIb), the group E is a linear or branched, preferably saturated, C₁-C₂₄More preferably C₁-C₁₀Even more preferably C₁-C₆A hydrocarbon chain, optionally interrupted by one or more nitrogen, sulfur or oxygen atoms. Preferably, the group E is selected from the group consisting of-R-, -NHR-, -OR-and-SR-, R being linear OR branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkylene group. Even more preferably, the group E is selected from the group consisting of-R-and-O-R-, R being a linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkylene group. Even more preferably, the group E is selected from-CH₂-、-CH₂-CH₂-、-CH₂-CH₂-CH₂-、-CH₂-CH₂-CH₂-CH₂-、-O-CH₂-、-O-CH₂-CH₂-、-O-CH₂-CH₂-CH₂and-O-CH₂-CH₂-CH₂-CH₂-。

Preferably, in the compounds of formulae (VI), (VIa) and (VIb), n is an integer greater than or equal to 1, more preferably n is an integer having a value of 1,2, 3 or 4; more preferably, n is an integer having a value of 1 or 2, even more preferably n ═ 1.

Preferably, in the compounds of formulae (VI), (VIa) and (VIb), R₁、R₂And R₃Independently of one another, represents a hydrogen atom or a hydrocarbon chainThe hydrocarbon chain is optionally substituted or interrupted with one or more heteroatoms (e.g., N, O and S). More preferably, the group R₁、R₂And R₃Independently of one another, represents a hydrogen atom or a linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkyl group. Even more preferably, the group R₁Is a hydrogen atom, a radical R₂And R₃Identical or different and being linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkyl group. Even more preferably, R₁、R₂And R₃The same and are hydrogen atoms.

According to a preferred embodiment of the invention, in formula (VIa), R₈Represents a radical of formula (V) as defined above, R₇、R₉、R₁₀And R₁₁Are the same or different and represent a hydrogen atom, C₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) Alkyl OR a group selected from-OR ', -NHR' and-SR ', R' being C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group.

Even more preferably, in this embodiment, R₈Represents a radical of formula (V) as defined above, R₁₀Represents a hydrogen atom, R₇、R₉And R₁₁Is represented by C₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) Alkyl, OR a group selected from-OR ', -NHR' and-SR ', R' being C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group.

Among the compounds of formula (VIa), particular preference is given to compounds having the following characteristics:

·R₇、R₉and R₁₁Are the same or different and represent C₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) Alkyl OR a group selected from-OR ', -NHR' and-SR ', R' being C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group; and is

·R₁₀Represents a hydrogen atom; and is

·R₈Represents a group of formula (V) wherein n ═ 1 or 2, preferably n ═ 1, the group E is selected from-R-and-O-R-, R is linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆Alkylene, even more preferably, the group E is selected from-CH₂-、-CH₂-CH₂-、-CH₂-CH₂-CH₂-、-CH₂-CH₂-CH₂-CH₂-、-O-CH₂-、-O-CH₂-CH₂-、-O-CH₂-CH₂-CH₂and-O-CH₂-CH₂-CH₂-CH₂-, a radical R₁、R₂And R₃Independently of one another, represents a hydrogen atom or a linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆Alkyl groups, and preferably all the same and are hydrogen atoms.

According to another preferred embodiment of the present invention, in formula (VIb), R₇Represents a radical of formula (V) as defined above, R₈To R₁₃Are the same or different and represent a hydrogen atom, C₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) Alkyl OR a group selected from-OR ', -NHR' and-SR ', R' being C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group. Even more preferably, in this embodiment, R₇A group of formula (V), R₈To R₁₃The same and represents a hydrogen atom.

Among the compounds of formula (VIb), particular preference is given to compounds having the following characteristics:

·R₇represents a group of formula (V) wherein n ═ 1 or 2, preferablyn-1, the group E is selected from-R-and-O-R-, R is linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆Alkylene, even more preferably, the group E is selected from-CH₂-、-CH₂-CH₂-、-CH₂-CH₂-CH₂-、-CH₂-CH₂-CH₂-CH₂-、-O-CH₂-、-O-CH₂-CH₂-、-O-CH₂-CH₂-CH₂and-O-CH₂-CH₂-CH₂-CH₂-, a radical R₁、R₂And R₃Independently of one another, represents a hydrogen atom or a linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆Alkyl groups, and preferably all the same and are hydrogen atoms; and

·R₈to R₁₃Are the same or different and represent a hydrogen atom, C₁-C₁₂(more preferably C)₁-C₆Even more preferably C₁-C₄) Alkyl OR a group selected from-OR ', -NHR' and-SR ', R' being C₁-C₁₂More preferably C₁-C₆Even more preferably C₁-C₄An alkyl group; more preferably, R₈To R₁₃The same and represents a hydrogen atom.

According to a particular embodiment, the compound of formula (I), preferably the compound of formula (VI), is selected from the group consisting of a compound of formula (VII) and a compound of formula (VIII)

The functionalizing agents of formula (VI) and preferred embodiments thereof may be obtained, for example, by a preparation process comprising at least the reaction (d) of an oxime compound of formula (IX) with an oxidizing agent in the presence of at least one organic solvent SL1 according to the following reaction scheme:

wherein

-a represents an arene diyl ring, optionally substituted by one or more carbon chains, which are identical or different and independent of each other, and optionally substituted or interrupted by one or more heteroatoms;

-n is an integer having a value greater than or equal to 1.

A, E, R as described above₁、R₂、R₃And the preferred forms of n are also applicable to the process for preparing the compound of formula (VI) from the compound of formula (IX).

Preferably, the oxidizing agent is selected from the group consisting of sodium hypochlorite, N-bromosuccinimide in the presence of a base, N-chlorosuccinimide in the presence of a base, and aqueous hydrogen peroxide solution in the presence of a catalyst. More preferably, the catalyst is selected from the group consisting of N-chlorosuccinimide in the presence of sodium hypochlorite and a base.

Advantageously, the amount of oxidizing agent is from 1 to 5 molar equivalents, preferably from 1 to 2 molar equivalents, relative to the molar amount of oxime compound of formula (IX).

Preferably, the organic solvent SL1 is selected from chlorinated solvents and solvents of the ester, ether and alcohol type, more preferably from dichloromethane, trichloromethane, ethyl acetate, butyl acetate, diethyl ether, isopropanol and ethanol, even more preferably from ethyl acetate, trichloromethane, dichloromethane and butyl acetate.

Preferably, the oxime compound of formula (IX) represents 1 to 30 wt.%, preferably 1 to 20 wt.%, relative to the total weight of the combination comprising said oxime compound of formula (IX), said organic solvent SL1 and said oxidizing agent.

The oxime compounds of the formula (IX) can be prepared by reacting at least one compound of the formula (X) with hydroxylamine NH₂Aqueous solution of OH (compound of formula (XI))The preparation of reaction (c) of the following reaction scheme results:

wherein:

-n is an integer having a value greater than or equal to 1.

A、E、R₁、R₂、R₃And the preferred forms of n are also applicable to the process for preparing the compound of formula (IX) from the compound of formula (X).

Preferably, hydroxylamine (compound of formula (XI)) is added at a temperature of 1 ℃ to 100 ℃, more preferably between 20 ℃ and 70 ℃.

Preferably, the aqueous hydroxylamine solution required for the above reaction is added in two stages.

More preferably, the compound of formula (X) is contacted with a first amount of the compound of formula (XI) in the range of 1.02 to 2 molar equivalents, preferably in the range of 1.1 to 1.75 molar equivalents, relative to the compound of formula (X); after 2 to 10 hours of this contact, a second amount of the compound of formula (XI) is then added to the reaction medium. This second amount of compound of formula (XI) is preferably in the range of 0.25 to 1.5 molar equivalents, preferably between 0.25 and 0.75 molar equivalents, with respect to the compound of formula (X).

The above reaction may be adapted to obtain the compound of formula (I) from the compound of formula (IX). In particular, the process for preparing the compounds of formula (I) wherein Q is a nitrone comprises reacting at least a compound of formula (X) with a compound of formula NR₄R₅-OHWherein R is₄And R₅The same or different (preferably different), and are as defined above (including preferred embodiments thereof).

The compound of formula (X) may be prepared by including at least in CO₂The preparation process of reaction (b) of carbonizing a compound of formula (XII) in the presence of an organic solvent SL2 and a catalyst is obtained according to the following reaction scheme:

wherein:

-n is an integer having a value greater than or equal to 1.

A、E、R₁、R₂、R₃And n are also applicable to the process for preparing the compound of formula (X) from the compound of formula (XII).

The catalyst may be selected from ammonium salts, alkaline earth metal salts (e.g. zinc or cobalt salts), late transition metal salts (e.g. aluminium, titanium or tin salts). Preferably, the catalyst is an ammonium salt, more preferably selected from Tetrabutylammonium (TBAB) and tetrabutylammonium bromide.

The organic solvent SL2 is selected from chlorinated solvents and solvents of the ester, ether, alcohol and amide type, more preferably from dichloromethane, trichloromethane, ethyl acetate, butyl acetate, diethyl ether, isopropanol, ethanol, N-Dimethylformamide (DMF), 1, 4-dioxane, even more preferably from DMF and 1, 4-dioxane.

The compound of formula (XII) can be obtained by a preparation process comprising at least the reaction (a) of a compound of formula (XIII) with a compound of formula (XIV) in the presence of at least one base and at a temperature of 20 ℃ to 150 ℃ according to the following reaction scheme:

wherein

-R₁、R₂and R₃Independently of one another, represents a hydrogen atom or a hydrocarbon chain, optionally substituted or interrupted by one or more heteroatoms;

-n is an integer having a value greater than or equal to 1,

-Y represents a nucleophilic group, and

-Z represents a nucleofugic group.

A、E、R₁、R₂、R₃And n are also suitable for use in a process for preparing a compound of formula (XII) from compounds of formula (XIII) and (XIV).

The term "nucleofugic group" is understood to mean a leaving group.

The term "nucleophilic group" is intended to mean a compound comprising at least one atom bearing a free electron pair or comprising a negatively charged atom.

Preferably, the Y group is selected from the group consisting of hydroxyl functional groups, thiol functional groups, primary amine functional groups and secondary amine functional groups.

The Z group may be selected from chlorine, bromine, iodine, fluorine, mesylate, tosylate, acetate and triflate.

More preferably, the Y group is a hydroxyl functional group and the Z group is chlorine.

The reaction between the compound of formula (XIII) and the compound of formula (XIV) is carried out in the presence of at least one base and at a temperature of 20 ℃ to 150 ℃.

The base may be selected from the group consisting of alkali metal alkoxides, alkali metal carbonates, alkaline earth metal carbonates, alkali metal hydroxides, alkaline earth metal hydroxides, and mixtures thereof.

Preferably, the base is selected from sodium methoxide, potassium carbonate and sodium hydroxide, more preferably potassium carbonate.

Preferably, the molar amount of base is from 1.5 to 8 molar equivalents, preferably from 2 to 6 molar equivalents, relative to the molar amount of compound of formula (XIII).

According to one embodiment, one or more catalysts may be added, selected from the group consisting of silver (I) salt type catalysts, quaternary ammonium type phase transfer catalysts and mixtures thereof.

The compounds of formula (XIII) and (XIV) as defined above are commercially available from commercial suppliers (e.g., Sigma-Aldrich, Merck, etc.).

According to a preferred embodiment, the process for the preparation of the compound of formula (VI) comprises at least the following successive reactions: reaction (c) is followed by reaction (d) as described above. Even more preferably, in this embodiment, the addition of the total amount of hydroxylamine is carried out in two stages in reaction (c).

According to another preferred embodiment, the process for the preparation of the compound of formula (VI) comprises at least the following successive reactions: as described above, reaction (a), followed by reaction (b), followed by reaction (c) and then followed by reaction (d). More preferably, in this preferred embodiment, the addition of the total amount of hydroxylamine is carried out in two stages in reaction (c).

The rubber composition according to the invention also comprises as component at least one diene elastomer, in particular at least one diene elastomer to which a compound of formula (I), in particular a compound of formula (VI), has been grafted.

"diene" elastomer (or rubber without distinction), whether natural rubber or synthetic rubber, is understood in a known manner to mean an elastomer which is at least partially (i.e. a homopolymer or a copolymer) composed of diene monomer units (monomers bearing two conjugated or non-conjugated carbon-carbon double bonds).

These diene elastomers can be divided into two categories: "substantially unsaturated" or "substantially saturated". "essentially unsaturated" is generally understood to mean a diene elastomer derived at least in part from conjugated diene monomers and having a content of units of diene origin (conjugated dienes) which is greater than 15% (mol%); thus, diene elastomers such as butyl rubbers or EPDM type copolymers of dienes and of alpha-olefins do not fall within the preceding definition, but can be described in particular as "essentially saturated" diene elastomers (low or very low content of units of diene origin, always less than 15%).

Diene elastomers which can be used in the context according to the invention are understood in particular to mean:

a. any homopolymer of a conjugated or non-conjugated diene monomer having from 4 to 18 carbon atoms;

b. any copolymer of a conjugated or non-conjugated diene having from 4 to 18 carbon atoms with at least one other monomer.

The other monomer may be ethylene, an olefin, or a conjugated or non-conjugated diene.

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

Suitable as non-conjugated dienes are non-conjugated dienes having from 6 to 12 carbon atoms, such as 1, 4-hexadiene, ethylidene norbornene or dicyclopentadiene.

Suitable as olefins are vinylaromatic compounds having from 8 to 20 carbon atoms and aliphatic alpha-monoolefins having from 3 to 12 carbon atoms.

Suitable as vinylaromatic compounds are, for example, styrene, (o-, m-or p-) methylstyrene, "vinyltoluene" commercial mixtures or p- (tert-butyl) styrene.

Suitable aliphatic alpha-monoolefins are in particular acyclic aliphatic alpha-monoolefins having from 3 to 18 carbon atoms.

More particularly, the diene elastomer is:

a. any homopolymer of conjugated diene monomer, in particular any homopolymer obtained by polymerization of conjugated diene monomer having from 4 to 12 carbon atoms;

b. any copolymer obtained by copolymerization of one or more conjugated dienes with each other or with one or more vinyl aromatic compounds having 8 to 20 carbon atoms;

c. copolymers of isobutylene and isoprene (butyl rubber) and halogenated versions (in particular chlorinated or brominated versions) of such copolymers;

d. any copolymer obtained by copolymerization of one or more conjugated or non-conjugated dienes with ethylene, an alpha-monoolefin or a mixture thereof, for example, elastomers obtained from ethylene, propylene and non-conjugated diene monomers of the type described above.

Preferably, the diene elastomer is chosen from ethylene/propylene/diene monomer (EPDM) copolymers, butyl rubber (IRR), Natural Rubber (NR), synthetic polyisoprene (IR), polybutadiene (BR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

Preferably, the diene elastomer is chosen from ethylene/propylene/diene monomer (EPDM) copolymers, butyl rubber (IRR), Natural Rubber (NR), synthetic polyisoprene (IR), polybutadiene (BR), butadiene/styrene copolymers (SBR), ethylene/butadiene copolymers (EBR), isoprene/butadiene copolymers (BIR) or isoprene/butadiene/styrene copolymers (SBIR), isobutylene/isoprene copolymers (butyl rubber-IIR), isoprene/styrene copolymers (SIR) and mixtures of these elastomers.

Preferably, the diene elastomer is chosen from ethylene/propylene/diene monomer copolymers, butyl rubbers and mixtures of these rubbers.

The diene elastomer is preferably chosen from natural rubber, synthetic polyisoprenes, polybutadienes, butadiene copolymers, isoprene copolymers and mixtures of these elastomers. More preferably, the diene elastomer is chosen from natural rubber, synthetic polyisoprenes, polybutadienes, butadiene/styrene copolymers, ethylene/butadiene copolymers, isoprene/butadiene/styrene copolymers, isobutylene/isoprene copolymers, isoprene/styrene copolymers and mixtures of these elastomers.

Preferably, the diene elastomer is chosen from polybutadienes, butadiene copolymers, isoprene copolymers and mixtures of these elastomers. More preferably, the diene elastomer is chosen from the group consisting of polybutadienes, butadiene/styrene copolymers, ethylene/butadiene copolymers, isoprene/butadiene/styrene copolymers, isobutylene/isoprene copolymers, isoprene/styrene copolymers and mixtures of these elastomers.

The following are suitable: polybutadiene (in particular polybutadiene having a content of 1,2 units (mol%) of between 4% and 80%, or polybutadiene having a content of cis-1, 4 units (mol%) of more than 80%), polyisoprene, butadiene/styrene copolymers (in particular butadiene/styrene copolymers having a Tg (glass transition temperature (Tg, measured according to ASTM D3418-99)) of between 0 ℃ and-90 ℃ and more particularly between-10 ℃ and-70 ℃, a styrene content of between 1% and 60% and more particularly between 20% and 50%, a content of 1, 2-bonds (mol%) of the butadiene moiety of between 4% and 75%, a content of trans-1, 4-bonds (mol%) of between 10% and 80%), butadiene/isoprene copolymers (in particular butadiene/styrene copolymers having an isoprene content of between 5% and 90% and a Tg of- Butadiene/isoprene copolymer at 40 ℃ to-80 ℃) or isoprene/styrene copolymer (in particular isoprene/styrene copolymer having a styrene content of between 5% and 50% by weight and a Tg of between-5 ℃ and-50 ℃). In the case of butadiene/styrene/isoprene copolymers, particularly suitable are those having a styrene content of between 5% and 50% by weight and more particularly between 10% and 40%, an isoprene content of between 15% and 60% by weight and more particularly between 20% and 50%, a butadiene content of between 5% and 50% by weight and more particularly between 20% and 40%, a1, 2-unit content (mol%) of the butadiene moiety of between 4% and 85%, a trans-1, 4-unit content (mol%) of the butadiene moiety of between 6% and 80%, a content (mol%) of 1, 2-plus 3, 4-units of the isoprene moiety of between 5% and 70%, a trans-1, 4-unit content (mol%) of the isoprene moiety of between 10% and 50%, more typically any butadiene/styrene/isoprene copolymer having a Tg between-5 ℃ and-70 ℃.

The diene elastomer may have any microstructure depending on the polymerization conditions used. These polymers may be, for example, block, random, sequential or microsequential polymers, and may be prepared in dispersion, emulsion or solution. Which may be coupled and/or star-branched, for example, by silicon or tin atoms linking the polymer chains together.

As indicated above, the rubber compositions according to the invention are based on at least one diene elastomer and at least one compound of formula (I), in particular of formula (VI). The diene elastomer may be grafted by a compound of formula (I), in particular by a compound of formula (VI), before incorporation into the rubber composition, or may be grafted by reaction with a compound of formula (I), in particular a compound of formula (VI), during the manufacture of the rubber composition. When the rubber composition comprises at least one elastomer grafted beforehand by a compound of formula (I), in particular by a compound of formula (VI), the molar degree of the compound of formula (I), in particular of formula (VI), grafted on said elastomer is in the range from 0.01% to 15%, preferably from 0.05% to 10%, more preferably from 0.07% to 5%. In the embodiment in which the elastomer is grafted by reaction with a compound of formula (I), in particular a compound of formula (VI), during the manufacture of the rubber composition, the content of compound of formula (I), in particular of compound of formula (VI), in the rubber composition according to the invention is in the range from 0.01phr to 150phr, preferably in the range from 0.02phr to 30 phr.

The rubber composition according to the invention may comprise one diene elastomer grafted by a compound of formula (I), in particular by a compound of formula (VI), whether grafted before introduction into the rubber composition or grafted by reaction with said compound of formula (I), in particular said compound of formula (VI), during the manufacture of the rubber composition, or a mixture comprising a plurality of diene elastomers, grafted, or some of them grafted, the remainder not grafted.

Other diene elastomers used in mixture with the grafted elastomer according to the invention are the conventional diene elastomers described above, whether star-branched, coupled, functionalized or not.

The grafted diene elastomer according to the invention is the predominant elastomer in the rubber composition when mixed with at least one other diene elastomer. It should be noted that the property improvement of the rubber composition according to the invention is higher when the proportion of said additional elastomer in the rubber composition according to the invention is lower.

The grafted diene elastomer according to the invention can be used in combination with any type of synthetic elastomer other than a diene elastomer, indeed even with polymers other than elastomers (for example thermoplastic polymers).

As indicated above, another component of the rubber composition according to the invention is a reinforcing filler.

Any type of "reinforcing" filler known to be able to reinforce the capacity of a rubber composition that can be used in particular for the manufacture of tyres may be used, such as organic fillers (for example carbon black), inorganic fillers (for example silica) or mixtures of these two types of filler.

Advantageously, the reinforcing filler is chosen from carbon black, inorganic fillers and mixtures thereof.

All carbon blacks, in particular carbon blacks conventionally used in tires or treads thereof, are suitable as carbon blacks. Among the carbon blacks, mention will be made more particularly of the reinforcing blacks of the series 100, 200 and 300, or of the blacks of the series 500, 600 or 700 (ASTM D-1765-2017 grade), such as the blacks N115, N134, N234, N326, N330, N339, N347, N375, N550, N683 and N772. These carbon blacks may be used in a separate state as is commercially available, or in any other form (e.g., as a carrier for some of the rubber additives used). The carbon black may, for example, have been incorporated into diene elastomers, in particular isoprene elastomers, in the form of a masterbatch (see, for example, applications WO 97/36724-A2 or WO 99/16600-A1). For carbon black, STSA specific surface area was determined according to standard ASTM D6556-2016.

The term "reinforcing inorganic filler" is understood herein to mean any inorganic or mineral filler (whatever its colour and its origin (natural or synthetic)), also known as "white" filler, "clear" filler or even "non-black" filler, with respect to carbon black, capable of reinforcing alone, without processes other than an intermediate coupling agent, a rubber composition intended for the manufacture of tyres. In a known manner, certain reinforcing inorganic fillers may be characterized in particular by the presence of hydroxyl (-OH) groups at their surface.

Mineral fillers of siliceous type (preferably Silica (SiO)₂) Mineral fillers (in particular alumina (Al)) or of the aluminous type₂O₃) Are particularly suitable as reinforcing inorganic fillers.

The silica used may be any reinforcing silica known to the person skilled in the art, in particular having a BET and CTAB specific surface area both of which are less than 450m²A/g, preferably of 30m²G to 400m²Any precipitated silica or fumed silica in the range of/g.

Any type of precipitated silica may be used, in particular highly dispersible precipitated silicas (referred to as "HDS" for "highly dispersible" or "highly dispersible silicas"). These precipitated silicas (which may or may not be highly dispersible) are well known to those skilled in the art. Mention may be made, for example, of the silicas described in applications WO 03/016215-A1 and WO 03/016387-A1. Among the commercial HDS silicas, mention may in particular be made of the silicas from Evonik

5000GR and

7000GR silica, or from Solvay

1085GR、

1115MP、

1165MP、

Premium 200MP and

HRS 1200MP silica. As non-HDS silica, the following commercial silicas can be used: from Evonik

VN2GR and

VN3GR silica, from Solvay

175GR silica or Hi-Sil EZ120G (-D), Hi-Sil EZ160G (-D), Hi-Sil EZ200G (-D), Hi-Sil 243LD, Hi-Sil 210 and Hi-Sil HDP 320G silicas from PPG.

In The present application, The BET specific surface area of inorganic fillers, in particular silica, is determined by gas adsorption using The Brunauer-Emmett-Teller method described in "The Journal of The American Chemical Society" (volume 60, page 309, month 2 1938), more specifically according to The method of standard NF ISO 5794-1, appendix E, adapted from month 6 2010 [ multipoint (5 points) volumetric method-gas: nitrogen-vacuum degassing: 1 hour at 160 ℃ -relative pressure p/po range: 0.05 to 0.17 ]. The CTAB specific surface area values were determined according to standard NF ISO 5794-1, 6 months 2010, appendix G. The method is based on the adsorption of CTAB (N-hexadecyl-N, N, N-trimethylammonium bromide) on the "outer" surface of the reinforcing filler.

When a reinforcing inorganic filler is used in the rubber composition according to the invention (particularly if the filler is silica), the BET surface area of the reinforcing inorganic filler is preferably 45m²G to 400m²In the range of/g, more preferably in the range of 60m²G to 300m²In the range of/g.

It is not important in what physical state the reinforcing inorganic filler is provided, whether it be in the form of a powder, microbeads, granules, beads or any other suitable densified form. Of course, reinforcing inorganic filler is also understood to mean mixtures of different reinforcing inorganic fillers, in particular mixtures of the silicas mentioned above.

For coupling the reinforcing inorganic filler to the diene elastomer, an at least bifunctional coupling agent (or bonding agent) aimed at providing a satisfactory chemical and/or physical connection between the inorganic filler (its particle surface) and the diene elastomer may be used in a known manner.

In particular, at least bifunctional organosilanes or polyorganosiloxanes are used. The term "bifunctional" is understood to mean a compound having a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the diene elastomer. For example, such a bifunctional compound may comprise a first functional group containing a silicon atom, capable of interacting with the hydroxyl groups of the inorganic filler, and a second functional group containing a sulfur atom, capable of interacting with the diene elastomer.

Preferably, the organosilane is selected from organosilane polysulfides (symmetrical or asymmetrical) (for example bis (3-triethoxysilylpropyl) tetrasulfide (abbreviated to TESPT) sold under the name Si69 by Evonik, or bis (triethoxysilylpropyl) disulfide (abbreviated to TESPD) sold under the name Si75 by Evonik), polyorganosiloxanes, mercaptosilanes, blocked mercaptosilanes (for example S- (3- (triethoxysilyl) propyl) octane thioesters sold under the name "NXT Silane" by Momentive). More preferably, the organosilane is an organosilane polysulfide.

Of course, it is also possible to use mixtures of the abovementioned coupling agents.

The content of coupling agent in the composition of the invention is advantageously less than or equal to 35phr, it being understood that it is generally desirable to use as little coupling agent as possible. Generally, the coupling agent is present in an amount comprised between 0.5% and 15% by weight with respect to the amount of reinforcing inorganic filler.

It will be understood by those skilled in the art that instead of the reinforcing inorganic filler described above, a reinforcing filler of another nature may be used, provided that it is covered with an inorganic layer (for example silica) or comprises, on its surface, functional sites (in particular hydroxyl sites) which require the use of a coupling agent to establish the bond between the reinforcing filler and the diene elastomer. By way of example, mention may be made of carbon black partially or completely covered with silica, or carbon black modified with silica, such as, without limitation, those of the CRX2000 series or CRX4000 series from Cabot Corporation

A type of filler.

The person skilled in the art knows how to adjust the content of reinforcing filler in the rubber composition of the invention according to the use concerned, in particular according to the type of tyre concerned, for example a tyre for motorcycles, passenger vehicles or utility vehicles (for example lorries or heavy vehicles). Preferably, the content of reinforcing filler is in the range from 10phr to 200phr, more preferably from 30phr to 180phr, the optimum content varying in a known manner depending on the specific target application.

According to one embodiment, the reinforcing filler comprises predominantly silica; it preferably consists essentially of silica, even more preferably consists of silica. In this embodiment, in which the reinforcing filler comprises mainly silica, the content of carbon black present in the rubber composition is preferably in the range from 2phr to 20 phr.

According to another embodiment of the invention, the reinforcing filler comprises mainly, indeed even essentially, and even more preferably consists of, carbon black.

Another component of the rubber composition according to the invention is a crosslinking agent.

The crosslinking agent may be any type of system known to those skilled in the art of tire rubber compositions. It may be based in particular on sulfur.

Preferably, the crosslinking agent is based on sulfur; it is referred to as a cure system. The sulphur may be provided in any form, in particular in the form of molecular sulphur or a sulphur donor. Also preferably at least one vulcanization accelerator is present, and optionally also preferably, various known vulcanization activators such as zinc oxide, stearic acid or equivalent compounds (e.g., stearates and transition metal salts), guanidine derivatives (especially diphenylguanidine), or known vulcanization retarders may be used.

Sulfur is used in an amount of preferably between 0.5phr and 12phr, in particular between 1phr and 10 phr. Vulcanization accelerators are used in amounts preferably between 0.5phr and 10phr, more preferably between 0.5phr and 5.0 phr.

As accelerators, any compound capable of acting as vulcanization accelerator for diene elastomers in the presence of sulfur can be used, in particular accelerators of the thiazole type and their derivatives, or of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate type. As examples of such accelerators, the following compounds may be mentioned in particular: 2-mercaptobenzothiazole disulfide (abbreviated MBTS), N-cyclohexyl-2-benzothiazolesulfenamide (CBS), N-dicyclohexyl-2-benzothiazolesulfenamide (DCBS), N- (tert-butyl) -2-benzothiazolesulfenamide (TBBS), N- (tert-butyl) -2-benzothiazolesulfenimide (TBSI), tetrabenzylthiuram disulfide (TBZTD), zinc dibenzyldithiocarbamate (ZBEC) and mixtures of these compounds.

The rubber compositions according to the invention may also comprise all or part of the usual additives and processing aids known to the person skilled in the art and generally used in rubber compositions for tires, in particular treads, such as plasticizers (for example plasticizing oils and/or plasticizing resins), non-reinforcing fillers, pigments, protective agents (for example antiozone waxes, chemical antiozonants, antioxidants), antifatigue agents or reinforcing resins (for example as described in application WO 02/10269).

Another subject of the invention is a process for preparing a rubber composition as described above.

The rubber compositions according to the invention are manufactured in a suitable mixer using two successive preparation stages known to those skilled in the art:

a first stage of thermomechanical working or kneading (the "non-productive" stage) carried out at a maximum temperature ranging from 110 ℃ to 200 ℃, preferably from 130 ℃ to 185 ℃, for a duration generally comprised between 2 minutes and 10 minutes,

a second stage of mechanical processing in an open mixer (e.g. open mill) (the "production" stage) after cooling the mixture obtained during the first non-production stage to a lower temperature (typically less than 120 ℃, for example between 40 ℃ and 100 ℃). The crosslinker is then added and the combined mixture is mixed for several minutes, for example between 5 and 15 minutes.

Generally, during the first "non-productive" stage, all the essential components of the composition according to the invention, i.e. the reinforcing filler and the coupling agent (where appropriate), with the exception of the chemical crosslinking agent, are intimately introduced into the diene elastomer(s) by kneading, i.e. at least these various essential components are introduced into a mixer in one or more steps and thermomechanically kneaded, until a maximum temperature of between 110 ℃ and 200 ℃, preferably between 130 ℃ and 185 ℃, is reached.

According to a first embodiment of the invention, the diene elastomer has been grafted by a compound of formula (I), in particular by a compound of formula (VI), before the rubber composition is manufactured. In this case, therefore, the grafted diene elastomer is introduced during the first "non-productive" stage. Thus, according to this first embodiment of the method, said method comprises the steps of:

modifying the diene elastomer by post-polymerization grafting, in solution or in bulk, a compound of formula (I) as defined above, in particular a compound of formula (VI),

introducing the reinforcing filler and all the essential components of the composition, except the crosslinking agent, into the diene elastomer grafted in this way by the compound of formula (I), in particular by the compound of formula (VI), by thermomechanically kneading the mixture one or more times until a maximum temperature of between 110 ℃ and 200 ℃, preferably between 130 ℃ and 185 ℃, is reached,

-cooling the aforesaid mixture to a temperature lower than 100 ℃,

-then introducing a cross-linking agent,

-kneading the mixture obtained in the preceding step to a temperature of less than 120 ℃.

The diene elastomer is grafted by reaction of said diene elastomer with a group Q carried by a compound of formula (I), in particular a nitrile oxide carried by a compound of formula (VI). During this reaction, the group Q forms a covalent bond with the chain of the diene elastomer. More precisely, the grafting of the compound of formula (I), in particular of formula (VI), is carried out by the [3+2] cycloaddition of the group Q (respectively nitrile oxide) to the unsaturation of the initial diene elastomer chain. The [3+2] cycloaddition mechanism can be found in document WO 2012/007441.

The diene elastomer bears, along the polymer main chain, one or more side groups deriving from the grafting reaction of the compound of formula (I) as described above, in particular of the compound of formula (VI). Advantageously, these side chain groups are randomly distributed along the polymer backbone.

The grafting of the compounds of the formula (I), in particular of the formula (VI), can be carried out in bulk, for example in an internal mixer or an open mixer, for example an open mill. The grafting is then carried out in an open or closed mixer at a temperature of less than 60 ℃ and the grafting reaction step is subsequently carried out in a press or in a furnace at a temperature of from 80 ℃ to 200 ℃ or in an open or closed mixer at a temperature of more than 60 ℃ without subsequent heat treatment.

The grafting process can also be carried out continuously or batchwise in solution. The diene elastomer thus grafted can be separated from its solution by any type of process known to the person skilled in the art, in particular by a steam stripping operation.

According to a second embodiment of the invention, the diene elastomer is grafted by a compound of formula (I), in particular of formula (VI), while the rubber composition is being manufactured. In this case, introduced during the first "non-productive" stage are the diene elastomer and the compound of formula (I) (in particular of formula (VI)) which have not been grafted. It is then preferable to add the reinforcing filler subsequently during this same non-productive phase, in order to prevent any side reactions of the compound of formula (I), in particular of formula (VI).

Thus, according to this second embodiment of the method, said method comprises the steps of:

-introducing at least one compound of formula (I) as defined above, in particular at least one compound of formula (VI), by thermomechanically kneading the mixture one or more times, and preferably subsequently introducing the reinforcing filler with all the essential components of the composition, except for the chemical crosslinking agent, into the diene elastomer until a maximum temperature of between 110 ℃ and 200 ℃, preferably between 130 ℃ and 185 ℃, is reached,

-cooling the mixture obtained in the preceding step to a temperature below 100 ℃,

-then introducing a cross-linking agent,

-kneading the mixture obtained in the preceding step to a maximum temperature of less than 120 ℃.

In both preferred embodiments, the molar degree of grafting of the compound of formula (I), in particular of the compound of formula (VI), is in the range from 0.01% to 15%, preferably from 0.05% to 10%, more preferably from 0.07% to 5%.

The term "molar degree of grafting" is understood to mean the number of moles of compound of formula (I), in particular of compound of formula (VI), grafted to the diene elastomer per 100 moles of monomer units constituting the diene elastomer. Can be analyzed by conventional polymer analysis methods (e.g.¹H NMR analysis) to determine the molar extent of grafting.

The final rubber composition thus obtained can then be calendered, for example in the form of a sheet or plate (in particular for characterization), or extruded in the form of a rubber profiled element that can be used as a semi-finished product for tires.

Another subject of the present invention is a semi-finished product for a tyre comprising a rubber composition as defined above; the semi-finished product is preferably a tread.

The subject of the invention is also a tire which preselects in all or part of its tread a rubber composition according to the invention as defined above.

The tyre according to the invention is preferably selected from tyres intended to fit two-wheeled vehicles, passenger vehicles, "heavy" vehicles (i.e. subways, buses, off-road vehicles, heavy road transport vehicles (such as trucks, tractors or trailers)) or aircraft, construction equipment, heavy agricultural vehicles or handling vehicles.

In addition to the above subject matter, the present invention also relates to at least one of the subject matters described in the following points:

1. rubber composition based on at least one diene elastomer, at least one reinforcing filler, at least one crosslinking agent and at least one compound of formula (I), optionally grafted to the elastomer

Wherein:

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

-a represents an arenediyl ring optionally substituted with one or more hydrocarbon groups, which may be the same or different and independent of each other, and optionally substituted or interrupted with one or more heteroatoms;

-n is an integer having a value greater than or equal to 1.

2. The composition according to point 1, wherein the diene elastomer is selected from the group consisting of ethylene/propylene/diene monomer copolymers, butyl rubber, natural rubber, synthetic polyisoprene, polybutadiene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

3. The composition according to point 1, wherein the diene elastomer is selected from the group consisting of ethylene/propylene/diene monomer copolymers, butyl rubbers and mixtures of these rubbers.

4. The composition according to point 1, wherein the diene elastomer is selected from the group consisting of natural rubber, synthetic polyisoprene, polybutadiene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

5. The composition according to point 1, wherein the diene elastomer is selected from the group consisting of polybutadienes, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

6. The composition according to point 1, wherein the diene elastomer is selected from the group consisting of polybutadienes, styrene/butadiene copolymers, isobutylene/isoprene copolymers, ethylene/butadiene copolymers, isoprene/styrene copolymers, isoprene/butadiene/styrene copolymers and mixtures of these elastomers.

7. The composition of any of points 1 to 6, wherein group Q is selected from the group consisting of nitrile oxide, nitrone, and nitrilimine.

8. The composition according to point 7, wherein the group Q is a group of the formula (II), (III) or (IV)

Wherein:

-symbol denotes the attachment of Q to a; and

9. The composition according to any one of points 1 to 8, wherein group A is C₆-C₁₄An arenediyl ring, optionally substituted with one or more hydrocarbon chains, which are the same or different and independent of each other, and optionally substituted or interrupted with one or more heteroatoms.

10. The composition according to point 9, wherein the compound of formula (I) is selected from the group consisting of compounds of formulae (Ia) and (Ib)

Wherein:

-the group Q is as defined according to any one of points 1, 9 and 10;

wherein, n, E, R₁、R₂And R₃As defined by the point 1, as well,

11. The composition according to point 10, wherein the compound of formula (I) is selected from compounds of formula (VI)

Wherein:

-n is an integer having a value greater than or equal to 1.

12. The composition according to point 11, wherein the group A is C₆-C₁₄An arenediyl ring, optionally substituted with one or more hydrocarbon chains, which are the same or different and independent of each other, and optionally substituted or interrupted with one or more heteroatoms.

13. The composition according to any one of points 1 to 12, wherein n ═ 1,2, 3, or 4, preferably n ═ 1 or 2, more preferably n ═ 1.

14. The composition according to any of points 1 to 13, wherein the group E is selected from linear or branched, preferably saturated, C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆A hydrocarbon chain, optionally interrupted by one or more nitrogen, sulfur or oxygen atoms.

15. The composition of any of points 1 to 14, wherein group E is selected from-R-OR-OR-, wherein R is C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkylene group.

16. The composition according to any one of points 1 to 15, wherein group E is selected from-CH₂-、-CH₂-CH₂-、-CH₂-CH₂-CH₂-、-CH₂-CH₂-CH₂-CH₂-、-O-CH₂-、-O-CH₂-CH₂-、-O-CH₂-CH₂-CH₂and-O-CH₂-CH₂-CH₂-CH₂-。

17. The composition according to any one of points 1 to 16, wherein the group R₁、R₂And R₃Independently of one another, represents a hydrogen atom or a linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkyl group.

18. The composition according to any one of points 1 to 17, wherein the group R₁Is a hydrogen atom, a radical R₂And R₃Identical or different and being linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkyl group.

19. The composition according to any one of points 1 to 18, wherein the group R₁And R₂And R₃Are all hydrogen atoms.

20. The composition of any of points 13 to 19, wherein the compound of formula (I) is selected from a compound of formula (VII) and a compound of formula (VIII)

21. The composition according to any one of points 1 to 20, wherein the reinforcing filler is selected from carbon black, inorganic reinforcing fillers and mixtures thereof.

22. The composition of point 21, wherein the reinforcing filler comprises carbon black.

23. The composition of point 21, wherein the reinforcing filler comprises an inorganic reinforcing filler.

24. The composition of point 23, wherein the inorganic reinforcing filler is silica.

25. The composition according to any one of points 1 to 24, wherein the molar degree of grafting of the compound of formula (I) is in the range of 0.01% to 15%, preferably 0.05% to 10%, more preferably 0.07% to 5%.

26. A method of preparing a rubber composition as defined in any of points 1 to 25, the method comprising the steps of:

modifying the diene elastomer by post-polymerization, in solution or in bulk, of a compound of formula (I), in particular of formula (VI);

introducing a reinforcing filler into the diene elastomer grafted by the compound of formula (I), in particular the compound of formula (VI), in this way by kneading the mixture one or more times until a maximum temperature of between 110 ℃ and 200 ℃, preferably between 130 ℃ and 185 ℃, is reached;

cooling the aforementioned mixture to a temperature of less than or equal to 100 ℃,

then introducing a chemical crosslinking agent, and

kneading the mixture obtained in the preceding step to a temperature of less than 120 ℃.

27. A method of preparing a rubber composition as defined in any of points 1 to 25, the method comprising the steps of:

introducing at least one compound of formula (I), in particular a compound of formula (VI), and preferably a reinforcing filler subsequently, into the diene elastomer by thermomechanically kneading the mixture one or more times during the bulk mixing until a maximum temperature of between 110 ℃ and 200 ℃, preferably between 130 ℃ and 185 ℃, is reached;

cooling the mixture obtained in the preceding step to a temperature of less than or equal to 100 ℃;

then the introduction of a chemical cross-linking agent,

28. The process according to point 26 or 27, wherein the diene elastomer is selected from the group consisting of ethylene/propylene/diene monomer copolymers, butyl rubber, natural rubber, synthetic polyisoprene, polybutadiene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

29. The process according to point 26 or 27, wherein the diene elastomer is selected from the group consisting of ethylene/propylene/diene monomer copolymers, butyl rubbers and mixtures of these rubbers.

30. The method according to point 26 or 27, wherein the diene elastomer is selected from the group consisting of natural rubber, synthetic polyisoprene, polybutadiene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

31. The process according to point 26 or 27, wherein the diene elastomer is selected from the group consisting of polybutadienes, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

32. The process according to point 26 or 27, wherein the diene elastomer is selected from the group consisting of polybutadienes, styrene/butadiene copolymers, ethylene/butadiene copolymers, isobutylene/isoprene copolymers, isoprene/styrene copolymers, isoprene/butadiene/styrene copolymers and mixtures of these elastomers.

33. The process of any one of points 26 to 32, wherein the molar degree of grafting of the compound of formula (I) is in the range of 0.01% to 15%, preferably 0.05% to 10%, more preferably 0.07% to 5%.

34. The method of any one of points 26 to 33, wherein group Q is selected from the group consisting of nitrile oxide, nitrone, and nitrilimine.

35. The method of point 34, wherein the group Q is a group of formula (II), (III) or (IV)

Wherein:

-symbol denotes the attachment of Q to a; and

36. The method of any one of points 26 to 35, wherein group a is C₆-C₁₄An arenediyl ring, optionally substituted with one or more hydrocarbon chains, which are the same or different and independent of each other, and optionally substituted or interrupted with one or more heteroatoms.

37. The method of point 36, wherein the compound of formula (I) is selected from the group consisting of compounds of formulae (Ia) and (Ib)

Wherein:

-the group Q is as defined according to any one of points 23, 31 and 32;

formula (Ia) is selected from R₇To R₁₁And formula (Ib) is selected from R₇To R₁₃A group of (A) representsA group of formula (V):

wherein n, E and R₁、R₂And R₃As defined by the point 1, as well,

38. The method of point 35, wherein the compound of formula (I) is selected from compounds of formula (VI)

Wherein:

-n is an integer having a value greater than or equal to 1.

39. The method of point 37, wherein the group A is C₆-C₁₄An arenediyl ring, optionally substituted with one or more hydrocarbon chains, which are the same or different and independent of each other, and optionally substituted or interrupted with one or more heteroatoms.

40. The method of any one of points 26 to 39, wherein n-1, 2, 3, or 4, preferably n-1 or 2, more preferably n-1.

41. The process according to any of points 26 to 40, wherein the group E is selected from linear or branched, preferably saturatedC of (A)₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆A hydrocarbon chain, optionally interrupted by one or more nitrogen, sulfur or oxygen atoms.

42. The method of any one of points 26 to 41, wherein group E is selected from-R-OR-OR-, wherein R is C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkylene group.

43. The method of any one of points 26 to 42, wherein group E is selected from-CH₂-、-CH₂-CH₂-、-CH₂-CH₂-CH₂-、-CH₂-CH₂-CH₂-CH₂-、-O-CH₂-、-O-CH₂-CH₂-、-O-CH₂-CH₂-CH₂and-O-CH₂-CH₂-CH₂-CH₂-。

44. The method according to any one of points 26 to 43, wherein the group R₁、R₂And R₃Independently of one another, represents a hydrogen atom or a linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkyl group.

45. The method of any one of points 26 to 44, wherein the group R₁Is a hydrogen atom, a radical R₂And R₃Identical or different and being linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkyl group.

46. Polymer modified according to any one of points 26 to 45, wherein the group R₁、R₂And R₃Are all hydrogen atoms.

47. The method of any one of points 36 to 46, wherein the compound of formula (V) is selected from a compound of formula (VII) and a compound of formula (VIII)

48. Semi-finished product for tyres comprising at least one rubber composition as defined in any one of points 1 to 25, or obtained according to the process as defined in any one of points 26 to 47.

49. Tire comprising at least one rubber composition as defined in any one of points 1 to 25, or obtained according to a process as defined in any one of points 26 to 47.

The following examples are intended to illustrate the invention, but not to limit it.

Examples

Determination of glass transition temperature

The glass transition temperature Tg of the polymers is measured by differential calorimetry (differential scanning calorimetry) according to the standard ASTM D3418-08.

Characterization of the molecules

Structural analysis and determination of molar purity of the synthesized molecules were carried out by NMR (french abbreviation "RMN") analysis. Spectra were collected on a Bruker Avance 3400MHz spectrometer equipped with a "5 mm BBFO Z-scale broadband" probe. Quantification of¹H NMR experiments used a simple 30 ° pulse sequence and a repetition time of 3 seconds between each of the 64 acquisitions. Unless otherwise stated, samples were dissolved in deuterated solvents (deuterated Dimethylsulfoxide (DMSO)). Deuterated solvents are also used for "lock-in" signals. For example, a calibration is performed on the proton signal of deuterated DMSO at 2.44ppm relative to the TMS reference at 0 ppm.¹H NMR spectra together with 2D¹H/¹³C HSQC and¹H/¹³the C HMBC experiment enables the determination of the molecular structure (refer to the partition table). By quantifying 1D¹The H NMR spectrum was subjected to molar quantification.

Molecules grafted to diene elastomer

The molar content of grafted compound tested on the diene elastomer was determined by NMR analysis. Spectra were collected on a 500MHz Bruker spectrometer equipped with a "5 mm BBFO Z-grade cryoprobe" probe. Quantification of¹H NMR experiments used a simple 30 pulse sequence and 5 seconds between each acquisitionThe time of repetition. Unless otherwise stated, the samples were dissolved in deuterated solvents (deuterated chloroform (CDCl)₃) In order to obtain a "lock" signal. 2D NMR experiments can determine the identity of the grafted units by chemical shift of the carbon atoms and protons.

Measurement of number average (Mn) molar Mass, weight average (Mw) molar Mass and polydispersity index of the diene elastomer

Size Exclusion Chromatography (SEC) was used. SEC can separate macromolecules in a solution according to their size through a column filled with a porous gel. The macromolecules are separated according to their hydrodynamic volume, with the largest volume of the macromolecule eluting first.

SEC enables the molar mass distribution of the elastomer to be understood, but is not an absolute method. The respective number average molar masses (Mn) and weight average molar masses (Mw) can be determined from commercial standards and the polydispersity index (PI ═ Mw/Mn) can be calculated by "molar" calibration.

No special treatment of the elastomer samples was performed prior to analysis. The sample was simply dissolved in chloroform or the following mixture at a concentration of about 1 g/l: tetrahydrofuran +1 vol% of diisopropylamine +1 vol% of triethylamine +1 vol% of distilled water (vol%: vol%). The solution was then filtered through a filter with a porosity of 0.45 μm before injection.

The apparatus used was a Waters Alliance chromatograph. Depending on the solvent used to dissolve the elastomer, the elution solvent is a mixture of: tetrahydrofuran +1 vol% of diisopropylamine +1 vol% of triethylamine, or chloroform. The flow rate was 0.7ml/min, the system temperature was 35 ℃ and the analysis time was 90 min. A set of four Waters columns in series were used, with the trade names Styragel HMW7, Styragel HMW6E and two Styragel HT 6E.

The volume of the elastomer sample solution injected was 100. mu.l. The detector was a Waters 2410 differential refractometer with a wavelength of 810 nm. The software used to process the chromatographic data was the Waters Empower system.

The calculated average molar mass is relative to a calibration curve generated from the PSS Ready Cal-Kit commercial polystyrene standards.

And (3) tensile test:

these tests enable determination of elastic stress and fracture properties after curing. Unless stated otherwise, these tests were performed according to French Standard NF T46-002, 9 months 1988. The actual secant modulus in MPa (i.e. calculated from the real cross-section of the reference specimen) was measured at 100% elongation (expressed as modulus of M100) and 300% elongation (M300) in the first elongation (i.e. without conditioning cycle). All these tensile measurements were carried out under standard conditions of temperature and humidity (23 ℃. + -. 2 ℃, 50%. + -. 5% relative humidity).

The results are expressed as a base 100 and the control is assigned an arbitrary value of 100 in order to calculate and compare M100 for the different samples tested. Calculating the value of the sample to be tested on the basis of 100 according to the following operations: (value of M100 of sample to be tested/value of M100 of control). times.100. The same calculation is done for the M300 and M300/M100 ratios. Of particular interest is the M300/M100 ratio, which gives an indication of enhanced properties. The higher the value of the M300/M100 ratio, the greater the improvement in the reinforcing properties.

Dynamic properties

The dynamic properties Δ G and tan (δ) max were measured on a viscosity analyzer (Metravib VA4000) according to the standard ASTM D5992-96. Samples of the vulcanized composition (thickness 4mm and cross-section 400 mm) subjected to a simple alternating sinusoidal shear stress at a frequency of 10Hz at 60 ℃ were recorded²Cylindrical sample of (d). The strain amplitude scan was performed from 0.1% to 100% (outward cycle) and then from 100% to 0.1% (return cycle).

These same measurements were also made at a temperature of 100 ℃.

The results used are the complex dynamic shear modulus difference (Δ G @) between 0.1% and 100% strain at 60 ℃_{Return at 60 ℃}(ii) a Payne effect) and loss factor tan (δ).

For the outward circulation, the maximum value of tan (. delta.) at 60 ℃ is indicated and is noted tan (. delta.)_{max60 deg.C outwards}. For the return cycle, the maximum value of tan (. delta.) at 100 ℃ is indicated and is noted as tan (. delta.)_{max100 ℃ return}。

The results are expressed as a base 100, and the control is assigned an arbitrary value of 100 in order to calculate and compare the tan (δ) of the different samples tested_{max60 deg.C outwards}. Calculating the value of the sample to be tested on the basis of 100 according to the following operations: (tan (. delta.) of sample to be measured)_max60℃Tan (delta) to the outlier/control_{max60 deg.C outwards}Value) × 100. In this way, a result of less than 100 indicates a decrease in hysteresis (and thus an improvement in hysteresis property), which corresponds to an improvement in rolling resistance property.

To express the result in base number 100, pair tan (δ)_{max100 ℃ return}And (Δ G;)_{Return at 60 ℃}) The same calculation is performed.

Δ G < 100_{Return at 60 ℃}The results show a better dispersion of the reinforcing filler in the rubber composition.

I-Synthesis of Compounds D and I

I-A/Synthesis of Compound D: 2- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) -1-naphthacenitrile oxide

2- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) -1-naphthacenitrile oxide was synthesized in 4 steps as described below. All chemical compounds used in this synthesis were obtained from "Sigma Aldrich".

Step 1: preparation of 2- (Oxiran-2-ylmethoxy) -1-naphthaldehyde (Compound A)

A solution of 2-hydroxy-1-naphthaldehyde (35.0 g; 0.203mol) in epichlorohydrin (270 ml; 320.0 g; 3.456 mol; 17 equivalents) was heated at a temperature of 130 ℃ for 3-5 minutes, after which trimethylbenzylammonium chloride (TMBAC; 3.8 g; 0.020 mol; 0.1 equivalent) was added. The reaction medium is heated to boiling (bath temperature 130-. After this period, the solution was cooled to 30-40 ℃ and then 400ml chloroform was added. The organic solution was washed 4 times with 150ml of water, the organic phase was then separated and concentrated under reduced pressure (11 mbar, bath temperature 50 ℃) to give 76.58g of oil. This oily residue was dissolved in 90ml of 2-propanol and the mixture was stirred for 5 to 10 minutes. The suspension obtained is then left at-18 ℃ for 4-5 hours. The precipitate was then filtered off and washed on the filter with cold 2-propanol (T ═ 18 ℃)3 times 20 ml. The product was dried at ambient temperature and atmospheric pressure.

A white solid was obtained with a melting point of 94.0-97.5 ℃ in a yield of 69% (32.13 g; 0.141 mol). Molar purity greater than 90%, (¹H NMR)。

2-hydroxy-1-naphthaldehyde is commercially available. It can be obtained, for example, from "Sigma Aldrich" (CAS 708-06-5).

Step 2: synthesis of 2- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) -1-naphthaldehyde (Compound B)

Compound A (2- (oxiran-2-ylmethoxy) -1-naphthaldehyde, 16.5 g; 72.3mmol), tetrabutylammonium bromide (1.17 g; 3.61 mmol; 0.05 eq.) and sodium ethylenediaminetetraacetate dihydrate (1.17 g; 3.14 mmol; 0.04 eq.) were mixed in 500ml of 1, 4-dioxane. In CO₂The mixture was heated at 100 c (bath temperature) in an atmosphere for 14-16 hours. Periodic addition of CO by bubbling into the medium₂To maintain stable CO₂And (4) pressure. After the mixture had cooled to ambient temperature, the precipitate was filtered off and washed on the filter with 1, 4-dioxane (2 times 10 ml). The filtrate was concentrated under reduced pressure (75 mbar, bath temperature 45 ℃) until a viscous residue was obtained (41.23 g). Ethyl acetate (20ml) and petroleum ether (30ml) (volume fraction 40/60) were added. After stirring for 10-15 minutes at ambient temperature, the precipitate obtained is filtered off and washed on the filter with an ethyl acetate/petroleum ether mixture (2 times, ethyl acetate/petroleum ether mixture: 5ml/10ml), then with water (3 times 10ml) and finally with petroleum ether (20 ml). A white solid (16.85g) was obtained in 86% yield.

The solid was then dissolved in ethanol (100 ml). After stirring for 10 minutes at the boiling temperature and cooling to ambient temperature (23 ℃), the reaction medium is cooled to +4 ℃ and held at this temperature for 15 to 20 hours. The precipitate was filtered off and washed on the filter with ethanol (2 times 10ml) and then dried in air at ambient temperature. The desired product (white powder with melting point 158-159 ℃) was obtained in 74% yield (14.52 g; 53.33mmol) and a molar purity of > 97%.

[ Table 1]

Numbering	δ¹H(ppm)	δ¹³C(ppm)
			1	10.68	190.8
2	/	116.0
			3	/	130.5
4	9.04	123.9
			5	7.60	129.8
6	7.43	124.9
			7	7.90	128.5
8	/	128.4
			9	8.25	137.9
10	7.52	114.5
			11	/	162.6
12	4.49-4.59	69.1
			13	5.23	74.6
14	4.50-4.63	66.1
			15	/	154.7

Solvent: DMSO (dimethylsulfoxide)

And step 3: synthesis of 2- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) -1-naphthaldehyde oxime (Compound C)

To a solution of compound B (2- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) -1-naphthaldehyde, 5.00 g; 18.37mmol) in ethanol (50ml) was added a solution of hydroxylamine (50% in water; 1.82 g; 27.5 mmol; 1.5 eq.) in ethanol (5ml) at 35 c (bath temperature). The reaction medium is heated to 40 ℃ and then stirred at this temperature for 8 hours. A second addition of a solution of hydroxylamine (50% in water; 0.61 g; 9.2 mmol; 0.5 eq.) in ethanol (25ml) was made. The reaction medium is stirred at 40 ℃ for 7 hours. After cooling to ambient temperature, the reaction medium is diluted by adding water (450ml) at 0 ℃ over 15-20 minutes. After stirring for 10 minutes, the precipitate was filtered off and washed with water (2 times 10ml) on the filter.

A white solid was obtained with a melting point of 182 ℃ and 183 ℃ in 67% yield (3.52 g; 12.25mmol) and a molar purity of more than 95%.

[ Table 2]

Solvent: DMSO (dimethylsulfoxide)

And 4, step 4: synthesis of 2- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) -1-naphthacenitrile oxide (Compound D)

To a suspension of 2- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) -1-naphthaldehyde oxime (product C) (3.42 g; 11.91mmol) in dichloromethane (75ml) at a temperature of +1 ℃ was added dropwise an aqueous solution of NaOCl in water (21.5 ml; 19.05 mmol; 1.6 equivalents)；>4% active chlorine solution) for 3-5 minutes. The reaction medium is stirred at this temperature for 70 to 80 minutes. The precipitate is filtered off and filtered over a filter with CH₂Cl₂(10ml) then washed with water (2 times 15ml) and finally with a dichloromethane/petroleum ether mixture (volume fraction 50/50) (10ml/10 ml). After drying at atmospheric pressure and ambient temperature, a white solid with a melting point of 157-.

[ Table 3]

Solvent DMSO

I-b/Synthesis of Compound I: 2,4, 6-trimethyl-3- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) benzonitrile oxide

2,4, 6-trimethyl-3- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) benzonitrile oxide was synthesized in 5 steps as described below. All chemical compounds used in this synthesis were obtained from "Sigma Aldrich".

Step 1: preparation of 3-hydroxy-2, 4, 6-trimethylbenzaldehyde (Compound E)

This compound can be obtained as 2,4, 6-trimethylphenol and dichloromethyl methyl ether (DCMME) according to the methods described in the following documents: yakubov, a.p.; tsyganov, d.v.; belen' kii, l.i.; krayushkin, M.M. bulletin of the academic of the Sciences of the USSR, Division of the Chemical Science (English translation); volume 40; stage 7.2; (1991); 1427-; izvestiya Akademiii Nauk SSSR, Seriya Khimicheskaya; stage 7; (1991); 1609-.

Obtaining the compound E with a melting point of 108-109 ℃, a yield of 83 percent and a molar purity of more than 90 percent (¹H NMR)。

2,4, 6-trimethylphenol is commercially available. It can be obtained, for example, from "Sigma Aldrich" (CAS 527-60-6).

Step 2: preparation of 2,4, 6-trimethyl-3- (oxiran-2-ylmethoxy) benzaldehyde (Compound F)

To a mixture of compound E (3-hydroxy-2, 4, 6-trimethylbenzaldehyde, 30.00 g; 0.183mol) and epichlorohydrin (42.3 g; 0.457mol) in acetonitrile (80ml) was added potassium carbonate (37.9 g; 0.274 mol). The reaction medium is heated at a temperature of 60 ℃ for 3 hours and then at a temperature of 70 ℃ for 2.5 to 3 hours. After cooling to a temperature of 40-50 ℃, the reaction medium was diluted with a mixture of water (250ml) and ethyl acetate (250ml) and then stirred for 10 minutes. The organic phase was separated and washed with water (4 times 100 ml). The solvent was evaporated under reduced pressure (bath temperature 40 ℃; 12 mbar). A yellow oil (39.116g) was obtained.

In the presence of a catalyst by column chromatography (SiO)₂(ii) a Ethyl Acetate (EA): after Petroleum Ether (PE) ═ 1:4) was separated and a fraction of the objective product was recovered, the solvent was evaporated under reduced pressure (bath temperature 40 ℃; 11 mbar). After evaporation, petroleum ether (150ml) was added to the residue obtained and the mixture was left at-18 ℃ for 2 hours. The precipitate obtained is filtered off and washed with petroleum ether (3 times 25ml) and finally dried in air.

A white solid (21.916g) was obtained in 55% yield.

And step 3: preparation of 2,4, 6-trimethyl-3- ((2-oxo-1, 3-dioxolan-4-yl) methoxy)) benzaldehyde (Compound G)

In CO₂The compound F (2,4, 6-trimethyl-3- (oxiran-2-ylmethoxy) benzaldehyde, 5.00 g; 22.70mmol), tetra-n-butylammonium bromide (TBAB; 0.366 g; 1.135mmol) and Na are mixed in 100ml of 1, 4-dioxane at a bath temperature equal to 110 ℃ in an atmosphere₂EDTA dihydrateCompound (0.422 g; 1.135 mmol). Periodic addition of CO by bubbling the medium for 7-8 hours₂To maintain CO₂The pressure was constant. Internal pressure is maintained by the balloon. After 14 hours a conversion of 60-65% is achieved. After cooling to a temperature of 60 ℃, the precipitate was filtered off and washed with 1, 4-dioxane (2 times 5 ml). The filtrate was concentrated under reduced pressure (bath temperature 50 ℃ C.; 30 mbar) to yield 5.323g of a brown oil.

In the presence of a catalyst by column chromatography (SiO)₂(ii) a After separating and recovering a fraction of the objective product from ethyl acetate-petroleum ether (1: 1), the solvent was evaporated under reduced pressure (bath temperature 40 ℃; 20 mbar). Petroleum ether (5ml) was added to achieve rapid precipitation. The precipitate was filtered off and washed with petroleum ether (2 times 5ml) and finally dried in air.

A white solid (1.835g) was obtained in 31% yield. Molar purity greater than 98%, (¹H NMR)。

[ Table 4]

Solvent DMSO

And 4, step 4: preparation of 2,4, 6-trimethyl-3- ((2-oxo-1, 3-dioxolan-4-yl) methoxy)) benzaldoxime (Compound H)

To compound G (2,4, 6-trimethyl-3- ((2-oxo-1, 3-dioxolan-4-yl) methoxy)) benzaldehyde, 1.200G at ambient temperature; 4.54mmol) in ethanol (50ml) was added sodium acetate (0.559 g; 6.81mmol) and hydroxylamine hydrochloride (0.473 g; 6.81mmol) in water (50 ml). The reaction mixture was stirred at ambient temperature for 3 hours. Then, a volume of 0 ℃ water (50ml) was added and the mixture was stirred for a further 15 minutes. The precipitate obtained is filtered off, washed with water (3 times 30ml) and dried in air.

A white solid (1.161g) was obtained with a melting point of 144-145 ℃ in 92% yield. Molar purity greater than 98%, (¹H NMR)。

[ Table 5]

Solvent DMSO

And 5: synthesis of 2,4, 6-trimethyl-3- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) benzonitrile oxide (Compound I)

To a solution of compound H (2,4, 6-trimethyl-3- ((2-oxo-1, 3-dioxolan-4-yl) methoxy)) benzaldehyde oxime, 1.01g, cooled to 0-2 ℃; 3.62mmol) in CHCl₃TEA (0.476 g; 4.70mmol) was added in one portion to the suspension (50ml) and N-chlorosuccinimide (NCS, 0.531 g; 3.98mmol) was added in portions over 1-2 minutes. The reaction mixture was stirred for 1 hour between 0 and 3 ℃. The organic phase was then washed with water (4 times 100ml) and concentrated under reduced pressure (bath temperature 25 ℃; 10 mbar) to give a yellow oil (1.606 g). Methyl tert-butyl ether (MTBE, 5ml) was then added. The precipitate obtained is filtered off, washed with MTBE (1: 1) and dried in air (2 times 5 ml).

A white solid (0.912g) was obtained with a melting point of 128-129 ℃ in a yield of 91%. Molar purity greater than 94%, (¹H NMR)。

[ Table 6]

Solvent: DMSO (dimethylsulfoxide)

II-rubber composition

II-1 preparation of rubber composition

The aim of this test is to demonstrate the improved properties of the rubber compositions comprising the grafted polymer bearing pendant cyclic carbonate functions according to the invention compared with rubber compositions comprising ungrafted polymer and with rubber compositions comprising polymers bearing pendant cyclic carbonate functions obtained by conventional routes (prior art polymers).

Three compositions based on SBR elastomers reinforced mainly by silica were thus prepared according to the process described below; these compositions differ from each other as follows:

control composition T1 (not according to the invention) comprises elastomer a, which is an ungrafted (unmodified) SBR comprising 26.5% by weight of styrene relative to the total weight of the elastomer and 24% by weight of 1, 2-butadiene units relative to the weight of the butadiene fraction; mn 120000g/mol, polydispersity index PI (french abbreviation "IP") -1.22, Tg-48 ℃;

composition C1 (not according to the invention) comprises an elastomer B with pendant cyclic carbonate functions obtained by radical polymerization; the molar content of cyclic carbonate functions in the elastomer is 2.6%;

composition C2 (according to the invention) comprises an elastomer C bearing a pendant cyclic carbonate function obtained by grafting compound D.

Obtaining elastomer B (not according to the invention)

Terpolymers of styrene, butadiene and 4- (hydroxymethyl) -1, 3-dioxolan-2-one methacrylate (CCMA) were synthesized by cold radical polymerization according to examples II-2 and II-3 (test 1) of document WO 2018015646. This process is repeated as follows.

The following raw materials were prepared in advance:

0.0627mol/l of Na₂FeP₂O₇Suspension in water: diluting FeSO with spray water₄,7H₂O and Na₄P₂O₇Then the mixture was heated at 60 ℃ for 45 minutes with regular stirring,

preparing a 0.079mol/l solution of cumene hydroperoxide in styrene,

preparing a solution of 0.223mol/l of mercaptan (R-SH) in styrene,

a10 g/l solution of N, N diethylhydroxylamine in water was prepared.

The reactor was packed according to the following operations:

introduction of spray water (final volume 22.3ml) at 25 ℃ over half an hour

Introduction of Sodium Dodecyl Sulfate (SDS) into nitrogen at 25 ℃ followed by a 10 minute nitrogen purge (0.3g)

Injection of a styrene feedstock containing R-SH (1ml of a 0.223mol/l solution) at 25 ℃ under nitrogen

Cooling the reactor to 5 deg.C

When the reactor reached about 12 ℃, the remaining styrene (1.815ml, 1.65g) and CCMA (0.39ml, 0.56g) were injected under nitrogen

Then injecting the butadiene feed (9.88ml, 6.42g)

The reactor was cooled to 5 ℃ and then Na was injected₂FeP₂O₇1.7ml of 0.0627mol/l solution)

Wait for 5 minutes, then inject the initiator and a solution of cumene hydroperoxide in styrene (0.5ml)

The end of the initiator addition marks the start of the polymerization (i.e. t ═ 0 min).

Stirring was continued at 5 ℃ for 7 hours and 15 minutes to reach a final conversion of about 63%.

Finally, a stop solution of N, N-diethylhydroxylamine in water was prepared. The latex is then terminated by decanting the monomer over the termination solution with residual pressure. The latex was then coagulated by adding 50ml of acetone. The coagulum was dried at 40 ℃ under partial vacuum under a nitrogen purge for 48 hours.

Table 9 below shows the operating conditions of the test.

[ Table 7]

Water (W)		22.3ml
			SDS	3phr	0.3g
RSH	0.16phr	0.016g
			FeSO₄,7H₂O	0.28phr	0.028g
Na₄P₂O₇	0.266phr	0.026g
			Mass% (mol%) of styrene	30.14％(19％)	3.014g
(mol%) of butadiene	64.23％(79％)	6.42g
			Mass% (mol%) of CCMA	5.63％(2％)	0.56g
Cumene hydroperoxide	0.17phr	0.017g
			N, N-diethylhydroxylamine	0.1phr	0.01g

The following table shows the characteristics of the elastomers obtained. The macrogel content was determined according to the method described on page 15 of document WO 2018/015646. The NMR characterization of the elastomer was carried out according to the procedure described in document WO 2018/015646, pages 15 and 16.

[ Table 8]

Obtaining the grafted elastomer C (according to the invention)

To 50g of SBR (elastomer A) was introduced 2- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) -1-naphthacenitrile oxide (6.908 g; 24.2 mmol; 92 mol% purity) in an open mill (open mixer at 23 ℃). The mixture was homogenized by 15 inversions. This mixing stage is followed by a heat treatment in a press at 120 ℃ and at a pressure of 10 bar for 10 minutes.

¹H NMR analysis makes it possible to verify a molar degree of grafting equal to 2.6% of 2- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) -1-naphthonitrile oxide and a molar grafting yield equal to 94%.

2- ((2-oxo-1, 3-dioxolan-4-yl) methoxy) -1-naphthacenitrile oxide is compound D, the synthesis of which has been described above.

Preparation of rubber composition

The elastomer, other than the vulcanization system, grafted or ungrafted or obtained by free radical polymerization, the reinforcing filler and other additives are introduced continuously to 85cm³The Polylab internal mixer of (a) had a final fill level of about 70% by volume and an initial vessel temperature of about 100 ℃. Thermomechanical working (non-productive phase) is then carried out in one step (total duration of kneading is equal to about 5min) until a maximum "discharge" temperature of 145 ℃ to 165 ℃ is reached. The mixture thus obtained is recovered and cooled, and then the vulcanization system is added in an open mixer, in which the second mechanical working stage is carried out at about 80 ℃ for about 5 to 6 minutes.

The composition thus obtained is then calendered in the form of a rubber sheet or a rubber thin sheet having a thickness of 2mm to 3mm to measure their physical or mechanical properties.

The following table gives the formulation of the rubber composition and shows the properties after curing (about 60 minutes at 150 ℃). Amounts are expressed in parts per 100 parts by weight of elastomer (phr).

[ Table 9]

Composition comprising a metal oxide and a metal oxide	T1	C1	C2
				Elastomer A	100	(-)	(-)
Elastomer B	(-)	100	(-)
				Elastomer C	(-)	(-)	100
Carbon black (1)	1	1	1
				Silicon dioxide (2)	67	67	67
Plasticizing resin (3)	31	31	31
				Antioxidant (4)	3	3	3
Paraffin wax	1	1	1
				Covering agent (5)	5.36	5.36	5.36
Diphenylguanidine (6)	2.5	2.5	2.5
				Stearic acid (7)	3	3	3
ZnO(8)	0.9	0.9	0.9
				Sulfur	2.3	2.3	2.3
CBS(9)	1	1	1

(1) ASTM N234 grade carbon black sold by Cabot;

(2) BET specific surface area from Solvay of 160m²(ii) Zeosil 1165MP silica per gram;

(3) hydrogenated C9/dicyclopentadiene resin E5600 BR sold by Exxon Mobil;

(4)1, 3-dimethylbutyl-N-phenyl-p-phenylenediamine (Santoflex 6-PPD, sold by Flexsys);

(5) trimethoxy (octyl) silane sold by Sigma Aldrich;

(6) diphenylguanidine (Perkacit DPG from Flexsys);

(7) stearin (Pristerene 4931-from Uniqema);

(8) zinc oxide (technical grade-from umcore);

(9) n-cyclohexyl-2-phenylthiazolesulfanimide (Santocure CBS from Flexys).

[ Table 10]

	T1	C1	C2
				ΔG*_{Return at 60 ℃}	100	66	18
Tan(δ)_{max60 deg.C outwards}	100	86	68
				Tan(δ)_{max100 ℃ return}	100	n.m.	44
M100 at 23 ℃	100	193	277
				M300 at 23 ℃	100	282	613
M300/M100 at 23 ℃	100	147	221

n.m.: not measured

According to the above table, it was observed that, as expected, composition C1 not according to the invention, comprising an elastomer bearing pendant cyclic carbonate functions obtained by conventional means, exhibits a reduced hysteresis (Tan (δ) compared with the control composition T1 (tao δ)_{max60 deg.C outwards}) Thus having improved hysteresis properties compared to the control composition T1 which does not comprise any modified elastomer. The non-conforming composition C1 also showed improved reinforcing properties (increased M300/M100 ratio) compared to the control composition T1.

Surprisingly, composition C2 according to the invention, comprising an elastomer bearing pendant cyclic carbonate functions obtained by post-polymerization grafting, shows significantly improved hysteresis and reinforcement properties compared with control composition T1 and composition C1 not according to the invention.

Claims

Wherein:

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

-n is an integer having a value greater than or equal to 1.

2. The rubber composition according to claim 1, wherein the diene elastomer is selected from ethylene/propylene/diene monomer copolymers, butyl rubber, natural rubber, synthetic polyisoprene, polybutadiene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

3. A rubber composition according to any preceding claim, wherein group Q is a group of formula (II), (III) or (IV)

Wherein:

-symbol denotes the attachment of Q to a; and

4. The rubber composition according to any of the preceding claims, wherein group A is C₆-C₁₄An arenediyl ring, optionally substituted with one or more hydrocarbon chains, which are the same or different and independent of each other, and optionally substituted or interrupted with one or more heteroatoms.

5. The rubber composition according to any one of claims 1 to 4, wherein the compound of formula (I) is selected from compounds of formulae (Ia) and (Ib)

Wherein:

-the group Q is as defined according to any one of claims 1 to 4;

wherein:

-n、E、R₁、R₂and R₃As defined in claim 1, wherein the first and second groups are,

6. A rubber composition according to any one of claims 3 to 5, wherein the compound of formula (I) in which the group Q is a nitrile oxide is selected from compounds of formula (VI)

Wherein:

-A is as defined in any one of claims 3 to 5,

-n is an integer having a value greater than or equal to 1.

7. A rubber composition according to any preceding claim, wherein n-1, 2, 3 or 4, preferably n-1 or 2, more preferably n-1.

8. Rubber composition according to any one of the preceding claims, in which group E is chosen from linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆A hydrocarbon chain, optionally interrupted by one or more nitrogen, sulfur or oxygen atoms.

9. Rubber composition according to any one of the preceding claims, wherein the group E is selected from-R-and-OR-, wherein R is a linear OR branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkylene group.

10. Rubber composition according to any one of the preceding claims, wherein the group R₁、R₂And R₃Independently of one another, represents a hydrogen atom or a linear or branched C₁-C₂₄Preferably C₁-C₁₀More preferably C₁-C₆An alkyl group.

11. The rubber composition according to claim 10, wherein the group R₁、R₂And R₃Represents a hydrogen atom.

12. The rubber composition according to any of the preceding claims, wherein the compound of formula (I) is selected from compounds of formula (VII) and compounds of formula (VIII)

13. The rubber composition according to any of the preceding claims, wherein the reinforcing filler is selected from carbon black, inorganic reinforcing fillers and mixtures thereof.

14. Semi-finished product for tyres comprising at least one rubber composition as defined in any one of claims 1 to 13.

15. Tire comprising at least one rubber composition as defined in any one of claims 1 to 13.