CN115916847A

CN115916847A - Grafted elastomers with pendant epoxy groups

Info

Publication number: CN115916847A
Application number: CN202180046216.XA
Authority: CN
Inventors: F·让-巴蒂斯特-迪特-多米尼克; K·马迈里
Original assignee: Compagnie Generale des Etablissements Michelin SCA
Current assignee: Compagnie Generale des Etablissements Michelin SCA
Priority date: 2020-06-29
Filing date: 2021-06-24
Publication date: 2023-04-04
Also published as: FR3111898B1; FR3111898A1; WO2022003279A1; CA3175376A1

Abstract

The present invention relates to a modified elastomer obtained by grafting at least one compound having formula (I) onto at least one unsaturated unit of a starting elastomer, wherein: -A is C ₆ ‑C ₁₄ An arenediyl ring, said C ₆ ‑C ₁₄ The arene diyl ring is optionally substituted by one or more hydrocarbon chains, which may be the same or different, aliphatic, preferably saturated, linear or branched; -E is C ₅ ‑C ₁₂ A divalent hydrocarbon group optionally comprising one or more heteroatoms; -X ₁ 、X ₂ 、X ₃ May be the same or different and represents a hydrogen atom, C ₁ ‑C ₆ Alkyl or C ₆ ‑C ₁₄ And (4) an aryl group. The invention also relates to a method for preparing such a modified elastomer and to a process based on at least one modified elastomerA combination of a modified elastomer and an additive.

Description

Grafted elastomers with epoxy side-chain groups

Technical Field

The field of the invention is that of elastomers modified with modifiers, more particularly diene elastomers modified in particular with 1,3-dipolar compounds.

Background

In the industrial field, it is common to use mixtures of elastomers with fillers (for example carbon black or silica).

In order to provide good properties to such mixtures, methods for improving the dispersion of the filler within the elastomer are constantly being sought.

In particular with respect to rubber compositions intended for tire manufacture, manufacturers are constantly looking for filled rubber compositions having good mechanical properties, such as reinforcement and as low hysteresis as possible. Specifically, the reduction in hysteresis of the rubber composition is advantageous for reducing the rolling resistance of the tire, and thus reducing the fuel consumption of a vehicle running with such a tire.

Many solutions have been attempted to achieve a good dispersion of the reinforcing filler in the rubber composition and to obtain rubber compositions having good reinforcing properties. In particular, mention may be made of modifying the structure of the elastomer by functionalizing agents, coupling agents or star branching agents.

More particularly, WO 2019/102132 A1 discloses an aromatic oxynitril compound comprising an epoxide ring via a divalent group-OCH as functionalizing agent ₂ -to an aromatic ring bearing a nitrile oxide. The functionalizing agent 2- (glycidyloxy) -1-naphthonitrile oxide improves the reinforcement index of compositions comprising such modified copolymers and significantly reduces the non-linearity of the compositions when grafted onto styrene-butadiene copolymers, as compared to compositions comprising unmodified styrene-butadiene copolymers. By keeping the hysteresis properties almost equal to those of a composition comprising an unmodified styrene-butadiene copolymerAt the same level of the post-sexual properties, improved enhancement and non-linear behavior of the composition is obtained.

However, there is still a need for modified elastomers (in particular modified diene elastomers) which provide compositions having improved hysteresis properties relative to the compositions of the prior art.

In fact, since fuel economy and the need to protect the environment have become priorities, it is necessary to ensure as low rolling resistance as possible. The rubber compositions used for the manufacture of pneumatic tires must have as low a hysteresis as possible in order to limit fuel consumption.

Obtaining rubber compositions with as low a level of hysteresis as possible while maintaining good other properties (such as reinforcement and stiffness) is a continuing challenge for tire manufacturers. In fact, it is known that a decrease in hysteresis of a rubber composition may be accompanied by a decrease in the baking stiffness (de rigidit a cut). However, the tread must be sufficiently stiff to ensure a good level of road behaviour of the tire.

It is therefore an object of the present invention to propose novel modified elastomers (in particular modified diene elastomers) which make it possible to obtain compositions having improved reinforcement index and improved hysteresis properties without reducing the bake stiffness properties.

Disclosure of Invention

In the course of continuing research, the applicant has surprisingly found that the use of aromatic nitrile oxide-modified elastomers having an epoxide ring linked to an aromatic group bearing a nitrile oxide by a specific divalent group enables compositions to be obtained having both an improved reinforcement index and an improved hysteresis property. Furthermore, advantageously, the compositions thus obtained also show an improvement in the bake stiffness properties.

The first subject of the invention therefore relates to a modified elastomer obtained by grafting at least one compound of formula (I) onto at least one unsaturation of the initial elastomer

Wherein:

-A represents C ₆ -C ₁₄ An arenediyl ring, said C ₆ -C ₁₄ The arene diyl ring is optionally substituted by one or more identical or different, preferably saturated, linear or branched, aliphatic hydrocarbon chains;

-E represents a divalent radical C ₅ -C ₁₂ A hydrocarbon group, the divalent C ₅ -C ₁₂ The hydrocarbyl group optionally contains one or more heteroatoms;

-X ₁ 、X ₂ and X ₃ May be the same or different and represents a hydrogen atom, C ₁ -C ₆ Alkyl or C ₆ -C ₁₄ And (4) an aryl group.

The invention also relates to a process for preparing a modified elastomer, comprising a step of grafting a compound of formula (I) onto an initial elastomer comprising at least one unsaturation by cycloaddition of a nitrile oxide of the compound of formula (I) on the unsaturation [3+2],

wherein:

-A represents C ₆ -C ₁₄ An arenediyl ring, said C ₆ -C ₁₄ The arylenediyl ring being optionally substituted by one or more identical or different, preferably saturated, linear or branched, aliphatic hydrocarbon chains;

Another subject of the invention relates to a composition comprising at least one modified elastomer as defined above or obtained according to the process described above and at least one additive.

The first subject of the invention relates to a modified elastomer obtained by grafting at least one compound of formula (I) onto at least one unsaturation of the initial elastomer

Wherein:

Detailed Description

Herein, 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 compounds of fossil origin or compounds of bio-based origin. In the case of compounds of bio-based origin, they may be partially or completely derived from biomass or may be obtained from renewable starting materials derived from biomass. In particular, elastomers, plasticizers, fillers, and the like.

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 a non-crosslinked state.

For the purposes of the present invention, the expression "parts by weight per hundred parts by weight of elastomer" (or phr) is understood to mean parts by mass per hundred parts by mass of elastomer.

The term "1,3-dipole compound" is understood according to the definition given by IUPAC. By definition, 1,3-dipole compounds comprise dipoles.

For the purposes of the present invention, the term "hydrocarbon chain" means a chain comprising one or more carbon atoms and one or more hydrogen atoms.

Expression "C _i -C _j Alkyl "represents a linear, branched or cyclic hydrocarbon group containing i to j carbon atoms; i and j are integers.

The expression "Ci-Cj aryl" denotes an aromatic group comprising from i to j carbon atoms; i and j are integers.

The term "alkanediyl" means a hydrocarbon group derived from an alkane in which two hydrogen atoms have been removed. Thus, an alkanediyl is a divalent group.

The invention and its advantages will be readily understood from the following description and exemplary embodiments.

The term "modified elastomer obtained by grafting" or "elastomer modified by grafting" denotes an elastomer comprising functional groups (in particular epoxide rings) which have been incorporated into the elastomer chain. In practice, the modified elastomer is obtained by grafting reaction of a compound bearing a functional group which is an epoxide ring and bearing a functional group capable of forming a covalent bond with the unsaturation of the elastomer, this functional group capable of forming a covalent bond being a nitrile oxide. Thus, the grafting reaction is attached to at least one unsaturation of the elastomer chain by a covalent bond of the compound of formula (I) bearing an epoxide ring.

As is known, elastomers generally comprise at least one main elastomer chain. This elastomeric chain may be referred to as the main chain, as long as all other chains of the elastomer are considered as side chains, as mentioned in the literature "Glossary of basic units in polymer science" (IUPAC recogmimentations, 1996), PAC,1996, 68, 2287, p 2294.

The term "unsaturation" means multiple covalent bonds between two carbon atoms: the multiple covalent bonds may be carbon-carbon double bonds or carbon-carbon triple bonds, with carbon-carbon double bonds being preferred.

For the purposes of the present invention, the term "initial elastomeric chain" means the elastomeric chain before the grafting reaction; the chain comprises at least one unsaturation capable of reacting with the compound of formula (I) above. Thus, the initial elastomer is the elastomer which acts as the starting reactant during the grafting reaction. The grafting reaction starting with the initial elastomer enables a modified elastomer to be obtained.

Preferably, the elastomer is a diene elastomer.

The term "diene elastomer" (or rubber without distinction), whether natural or synthetic, is understood in a known manner to mean an elastomer consisting at least in part (i.e. a homopolymer or a copolymer) 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". The term "essentially unsaturated" generally denotes 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 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%).

The term "diene elastomer which can be used in the context of the present invention" means in particular:

-any homopolymer of conjugated or non-conjugated diene monomers comprising from 4 to 18 carbon atoms;

any copolymer of a conjugated or non-conjugated diene comprising 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 conjugated dienes include conjugated dienes containing from 4 to 12 carbon atoms, particularly 1,3-diene, such as 1,3-butadiene and isoprene, among others.

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

Suitable olefins include vinyl aromatic compounds containing from 8 to 20 carbon atoms and aliphatic alpha-monoolefins containing from 3 to 12 carbon atoms.

Suitable vinyl aromatic compounds include, for example, styrene, (ortho-, meta-, or para-) methylstyrene, "vinyltoluene" commercial mixtures or para- (tert-butyl) styrene.

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

More particularly, the diene elastomer may be:

-any homopolymer of conjugated diene monomer, in particular any homopolymer obtained by polymerization of conjugated diene monomer comprising from 4 to 12 carbon atoms;

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

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

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 initial elastomer is preferably a diene elastomer selected from the group consisting of ethylene/propylene/diene monomer (EPDM) copolymers, natural Rubber (NR), synthetic polyisoprene (IR), polybutadiene (BR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

Preferably, the initial elastomer is preferably a diene elastomer selected from the group consisting of ethylene/propylene/diene monomer (EPDM) copolymers, 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 initial elastomer is preferably a diene elastomer selected from ethylene/propylene/diene monomer copolymers, butyl rubbers and mixtures of these rubbers.

Preferably, the initial elastomer is preferably a diene elastomer selected from the group consisting of natural rubber, synthetic polyisoprene, polybutadiene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

More preferably, the initial elastomer is preferably a diene elastomer selected from the group consisting of natural rubber, synthetic polyisoprene, polybutadiene, butadiene/styrene copolymers, ethylene/butadiene copolymers, isoprene/butadiene/styrene copolymers, isobutylene/isoprene copolymers, isoprene/styrene copolymers and mixtures of these elastomers.

Preferably, the initial elastomer is preferably a diene elastomer selected from natural rubber, synthetic polyisoprenes, isoprene copolymers and mixtures of these elastomers.

The initial elastomer (preferably diene elastomer) that can be used in the context of the present invention may have any microstructure that varies with the polymerization conditions used. These elastomers may be, for example, block elastomers, random elastomers, sequential elastomers or microsequential elastomers, and may be prepared in dispersion, emulsion or solution. It may be coupled and/or star-branched, for example by silicon or tin atoms linking the elastomer chains together.

According to the invention, the initial elastomer, preferably a diene elastomer, is modified by grafting a compound of formula (I) as defined above, also referred to as modifier.

According to formula (I), the modifier comprises a group A which represents C ₆ -C ₁₄ An arenediyl ring, said C ₆ -C ₁₄ The arylenediyl ring is optionally substituted by one or more identical or different, preferably saturated, linear or branched, aliphatic hydrocarbon chains.

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

The term "monocyclic or polycyclic aromatic hydrocarbon group" means one or more aromatic rings whose skeleton is composed of carbon atoms. In other words, no heteroatoms are present 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); these fused rings then share at least two consecutive carbon atoms. These rings may be single-sided or fused to each other. The arene bicyclic ring comprises from 6 to 14 carbon atoms.

The arene bicyclic ring may be unsubstituted, partially substituted, or fully substituted. The arylenediyl ring is partially substituted when one or two or more hydrogen atoms (but not all atoms) are replaced by one or two or more, preferably saturated, linear or branched, aliphatic hydrocarbon chains. The chains are also referred to as substituents. If all hydrogen atoms are replaced by the chain, the arene bicyclic ring is fully substituted. The substituents of the arylenediyl ring may be the same or different from each other.

Preferably, when the arene diyl ring is substituted by one or more hydrocarbon chains (which may be the same or different and independent of each other), the chain or chains are inert with respect to the epoxide ring and the nitrile oxide.

For the purposes of the present invention, the term "hydrocarbon chain which is inert with respect to the epoxide ring and the nitrile oxide" means a hydrocarbon chain which does not react with said epoxide ring or said nitrile oxide. Thus, the hydrocarbon chain which is inert with respect to the ring and the nitrile oxide is, for example, a hydrocarbon chain without any alkenyl or alkynyl functional group capable of reacting with the ring or the nitrile oxide. Preferably, these hydrocarbon chains are linear or branched, saturated aliphatic chains and may contain from 1 to 24 carbon atoms.

Preferably, A represents C ₆ -C ₁₄ An arenediyl ring, said C ₆ -C ₁₄ The arene diyl ring being optionally saturated by one or more C, which may be the same or different ₁ -C ₂₄ A hydrocarbon chain is substituted. Even more preferably, the group A is C ₆ -C ₁₄ An arenediyl ring, said C ₆ -C ₁₄ The arenediyl ring is optionally substituted by one or more identical or different substituents C ₁ -C ₁₂ Preferably C ₁ -C ₆ Even more preferably C ₁ -C ₄ An alkyl group.

Preferably, the compound of formula (I) according to the invention is selected from the group consisting of compounds of formula (Ia) and compounds of formula (Ib)

Wherein:

-R of formula (Ia) ₁ To R ₅ And a radical of the formula (Ib) selected from R ₁ To R ₇ Represents a group of the following formula (II):

of which E, X ₁ 、X ₂ And X ₃ As defined above, the symbol (, denotes that the group of formula (II) is attached to the remainder of molecule (Ia) or (Ib);

formula (Ia) is selected from R ₁ To R ₅ With the exception of one radical representing the radical of formula (II) and the radical of formula (Ib) is selected from R ₁ To R ₇ The six groups other than the one representing the group of formula (II) may be the same or different and represent, independently of each other, a hydrogen atom or a preferably saturated, linear or branched aliphatic hydrocarbon chain.

Preferably, in the formulae (Ia) and (Ib)In which compound of formula (Ia) is selected from R ₁ To R ₅ With the exception of one radical representing the radical of formula (II) and the radical of formula (Ib) is selected from R ₁ To R ₇ May be the same or different and independently of one another represent a hydrogen atom or a saturated, linear or branched C ₁ -C ₂₄ An aliphatic hydrocarbon chain.

Even more preferably, in the compounds of formula (Ia) and (Ib), formula (Ia) is selected from R ₁ To R ₅ With the exception of one radical representing the radical of formula (II) and the radical of formula (Ib) is selected from R ₁ To R ₇ May be the same or different and is selected from the group consisting of a hydrogen atom and C ₁ -C ₁₂ Preferably C ₁ -C ₆ Even more preferably C ₁ -C ₄ An alkyl group.

Even more preferably, in the compounds of formula (Ia) and (Ib), formula (Ia) is selected from R ₁ To R ₅ With the exception of one radical representing the radical of formula (II) and the radical of formula (Ib) is selected from R ₁ To R ₇ The six groups other than the one group representing the group of formula (II) may be the same or different and represent, independently of each other, a hydrogen atom or a methyl group.

According to a preferred embodiment of the invention, in formula (Ia), R ₂ A group of formula (II), R ₁ 、R ₃ 、R ₄ And R ₅ May be the same or different and represents a hydrogen atom or a preferably saturated, linear or branched C ₁ -C ₂₄ An aliphatic hydrocarbon chain. More preferably, R ₂ A group of formula (II), R ₁ 、R ₃ 、R ₄ And R ₅ May be the same or different and is selected from a hydrogen atom and C ₁ -C ₁₂ More preferably C ₁ -C ₆ Even more preferably C ₁ -C ₄ An alkyl group.

Even more preferably, in this embodiment, R ₂ A group of formula (II), R ₄ Represents a hydrogen atom, R ₁ 、R ₃ And R ₅ Denotes preferably saturated, linear or branchedC of (A) ₁ -C ₂₄ An aliphatic hydrocarbon chain. Even more preferably, R ₂ A group of formula (II), R ₄ Represents a hydrogen atom, R ₁ 、R ₃ And R ₅ May be the same or different and represents C ₁ -C ₁₂ More preferably C ₁ -C ₆ Even more preferably C ₁ -C ₄ An alkyl group.

According to another preferred embodiment of the present invention, in formula (Ib), R ₁ A group of formula (II), R ₂ To R ₇ May be the same or different and represents a hydrogen atom or a preferably saturated, linear or branched C ₁ -C ₂₄ An aliphatic hydrocarbon chain. More preferably, R ₁ A group of formula (II), R ₂ To R ₇ May be the same or different and is selected from a hydrogen atom and C ₁ -C ₁₂ More preferably C ₁ -C ₆ Even more preferably C ₁ -C ₄ An alkyl group. Even more preferably, in this embodiment, R ₁ A group of formula (II), R ₂ To R ₇ The same and represents a hydrogen atom.

In the compounds of formulae (I), (Ia) and (Ib), E represents a divalent C ₅ -C ₁₂ A hydrocarbyl group, which may optionally contain one or more heteroatoms. For the purposes of the present invention, the term "divalent hydrocarbon radical" is intended to mean the radical X attached to the oxygen atom of A ₁ 、X ₂ And X ₃ A spacer group (or linker group) forming a bridge between the epoxide rings of (a), the spacer group E comprising from 5 to 12 carbon atoms. The spacer group may be C ₅ -C ₁₂ A hydrocarbon chain, which is preferably saturated, linear or branched, and may optionally contain one or more heteroatoms, such as N, O and S. The hydrocarbon chain may be optionally substituted, provided that the substituent does not react with nitrile oxide and epoxide rings as defined above. Surprisingly, when E comprises from 5 to 12 carbon atoms, the compounds of formula (I), when grafted onto an elastomer, preferably a diene elastomer, confer to the compositions based on said grafted elastomer improved hysteresis and reinforcing properties with respect to the compositions of the prior art. Surprisingly, the improvement in these properties does not reduce the bake stiffness properties.

Preferably, in the compounds of formulae (I), (Ia) and (Ib), E represents a divalent C ₅ -C ₁₀ Preferably C ₅ -C ₉ More preferably C ₆ -C ₉ Even more preferably C ₇ -C ₉ Hydrocarbyl groups, which may optionally contain one or more heteroatoms, e.g., N, O and S. Surprisingly, when E is such a divalent compound as described above, the compound of formula (I), when grafted onto an elastomer, preferably a diene elastomer, confers to the compositions based on said grafted elastomer improved hysteresis and reinforcing properties with respect to the compositions of the prior art. Surprisingly, the improvement in these properties does not reduce the bake stiffness properties.

More preferably, in the compounds of formulae (I), (Ia) and (Ib), E represents C ₅ -C ₁₀ Alkanediyl, preferably C ₅ -C ₉ Alkanediyl, more preferably C ₆ -C ₉ Alkanediyl, even more preferably C ₇ -C ₉ An alkanediyl group. Surprisingly, when E is such an alkanediyl as described above, the compound of formula (I), when grafted onto an elastomer, preferably a diene elastomer, confers to compositions based on said grafted elastomer improved hysteresis and reinforcing properties with respect to the compositions of the prior art. Surprisingly, the improvement in these properties does not reduce the bake stiffness properties.

Preferably, in the compounds of formulae (I), (Ia) and (Ib), X ₁ 、X ₂ And X ₃ May be the same or different and is selected from a hydrogen atom, C ₁ -C ₆ Alkyl and C ₆ -C ₁₄ And (3) an aryl group.

Preferably, in the compounds of formulae (I), (Ia) and (Ib), X ₁ 、X ₂ And X ₃ May be the same or different and is selected from a hydrogen atom, a methyl group, an ethyl group and a phenyl group.

According to a preferred embodiment of the present invention, in the compounds of formulae (I), (Ia) and (Ib), X ₁ 、X ₂ And X ₃ The same and represents a hydrogen atom.

According to another preferred embodiment of the present invention, in the compounds of formulae (I), (Ia) and (Ib), X ₁ And X ₂ Represents a hydrogen atom, X ₃ Represents a phenyl group.

According to another preferred embodiment of the present invention, in the compounds of formulae (I), (Ia) and (Ib), X ₃ Is a hydrogen atom, X ₁ And X ₂ May be the same or different and represents a hydrogen atom or a methyl group.

Preferably, the compound of formula (I) may be a compound of formula (Ib), wherein the group R ₁ Is a radical of formula (II) and the radical E represents C ₅ -C ₁₀ Alkanediyl, preferably C ₅ -C ₉ Alkanediyl, more preferably C ₆ -C ₉ Alkanediyl, even more preferably C ₇ -C ₉ Alkanediyl, radical X ₁ 、X ₂ And X ₃ May be the same or different and is selected from a hydrogen atom, C ₁ -C ₆ Alkyl and C ₆ -C ₁₄ Aryl (preferably selected from hydrogen and C) ₁ -C ₆ Alkyl) and the radical R ₂ To R ₇ May be the same or different and is selected from a hydrogen atom and C ₁ -C ₁₂ An alkyl group.

Particularly preferred compounds of formula (I) are compounds of formula (III):

the compounds of (I), (Ia), (Ib) and (III) of the invention can be obtained in particular by a preparation process comprising at least one reaction (d) of an oxime compound of the formula (IV) with an oxidizing agent in the presence of at least one organic solvent SL1 according to the following reaction scheme, in order to obtain the compounds of the formula (I) (in particular the preferred compounds thereof):

wherein:

-A represents C ₆ -C ₁₄ An arenediyl ring, said C ₆ -C ₁₄ The arenediyl ring is optionally substituted by one or more identical or different, preferably saturated, linear or branched, aromatic hydrocarbon ringsSubstituted aliphatic hydrocarbon chain;

A, E, X as described above ₁ 、X ₂ And X ₃ Is also applicable to the process for preparing the compound of formula (I) from the compound of formula (IV).

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 an aqueous hydrogen peroxide solution in the presence of a catalyst. More preferably, the catalyst is selected from the group consisting of N-bromosuccinimide in the presence of sodium hypochlorite and a base. Preferably, the base may be triethylamine.

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 (IV).

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 (IV) accounts for 1 to 30 wt%, preferably 1 to 20 wt%, relative to the total weight of the combination comprising the oxime compound of formula (IV), the organic solvent SL1 and the oxidizing agent.

The oximes of formula (IV) can be obtained in particular by reaction of a compound of formula (V) with hydroxylamine NH ₂ An aqueous solution of OH (compound of formula (VI)) is obtained according to at least one preparation method of reaction (c) of the following reaction scheme:

wherein:

A, E, X as described above ₁ 、X ₂ And X ₃ Is also applicable to the process for preparing the compound of formula (IV) from the compound of formula (V).

Preferably, hydroxylamine (compound of formula (VI)) is added in the temperature range of 1 ℃ to 100 ℃, more preferably between 20 ℃ and 70 ℃.

The compound of formula (V) may be obtained by a preparation process comprising at least one reaction (b) of a compound of formula (VII) with a compound of formula (VIII) in the presence of at least one base at a temperature ranging from 20 ℃ to 150 ℃ according to the following reaction scheme:

wherein

-X ₁ 、X ₂ and X ₃ Can be the same or different, andrepresents a hydrogen atom, C ₁ -C ₆ Alkyl or C ₆ -C ₁₄ An aryl group;

-Z represents a nucleofugic group.

A、E、X ₁ 、X ₂ And X ₃ Is also applicable to the process for preparing the compound of formula (V) from the compound of formula (VIII) and the compound of formula (VII).

The term "nucleofugic group" means a leaving group. The group Z may be selected from chlorine, bromine, iodine, fluorine, mesylate, tosylate, acetate and triflate groups. Preferably, Z is bromo.

The reaction between the compound of formula (VIII) and the compound of formula (VII) is carried out in the presence of at least one base at a temperature ranging from 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 (VII).

According to one embodiment, one or more catalysts may be added, selected from the silver salt type (for example silver oxide Ag) ₂ O), quaternary ammonium salt type phase transfer catalysts and mixtures thereof.

The compounds of formula (VII) as defined above are commercially available from suppliers such as Sigma-Aldrich, merck, chimieliva, etc.

The compound of formula (VIII) can be obtained by epoxidation of the corresponding olefin of formula (IX) according to the following reaction scheme. The synthesis of compounds containing an epoxide ring from the corresponding olefin is well known. For example, the oxidation may be carried out in the presence of a peracid (e.g., m-chloroperbenzoic acid, peracetic acid, or performic acid). Another known technique is to use dimethyldioxirane.

E, X as described above ₁ 、X ₂ And X ₃ Is also applicable to the process for preparing the compound of formula (VIII) from the compound of formula (IX).

The compounds of formula (IX) are commercially available from suppliers such as Sigma-Aldrich and ABCR.

As previously mentioned, compounds of formula (I), in particular compounds of formula (Ib), even more in particular compounds of formula (III), are used as agents for modifying elastomers, preferably diene elastomers. Which may be grafted to one or more elastomers containing at least one unsaturated carbon-carbon bond; in particular, the elastomer may be a diene elastomer as defined previously. The modified elastomers obtained by grafting the compounds of formula (I), in particular the modified elastomers obtained by grafting the compounds of formula (Ib), in particular the modified elastomers obtained by grafting the compounds of formula (III), advantageously enable compositions to be obtained which simultaneously exhibit an improvement in the reinforcement index and an improvement in the hysteresis properties. Furthermore, advantageously, compositions comprising these modified elastomers also show an improvement in the bake stiffness properties.

The subject of the present invention is also a process for preparing a modified elastomer, comprising a step of grafting a compound of formula (I) as defined above, in particular a compound of formula (Ib), more in particular a compound of formula (III), including preferred embodiments thereof, onto an initial elastomer comprising at least one unsaturation by cycloaddition of a compound of formula (I), in particular a compound of formula (Ib), more in particular a nitrile oxide of a compound of formula (III), over the unsaturation [3+2 ]. In the process, preferably, the initial elastomer may be a diene elastomer, in particular a diene elastomer as defined above.

The grafting of these compounds is carried out by cycloaddition of the nitrile oxide functions carried by said compounds of formula (I), in particular by the compounds of formula (Ib), more particularly by the compounds of formula (III), on the unsaturated carbon-carbon bonds of the elastomeric chain [3+2 ]. The mechanism of this cycloaddition is particularly illustrated in WO 2012/007441. During this reaction, the compound of formula (I), in particular the compound of formula (Ib) or (III), forms covalent bonds with the elastomer chain.

According to the invention, the modified elastomer bears, along the main elastomer chain, one or more side chain groups derived from the grafting reaction of a compound of formula (I) as defined above, in particular a compound of formula (Ib), more in particular a compound of formula (III). Advantageously, these side chain groups are randomly distributed along the main elastomer chain.

According to a preferred embodiment, the molar degree of grafting of the compound of formula (I), in particular of the compound of formula (Ib), more in particular of the compound of formula (III), 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" means the number of moles of compound of formula (I), in particular of compound of formula (Ib), more in particular of compound of formula (III), grafted onto the elastomer per 100 moles of monomer units constituting the initial elastomer. Can be analyzed by conventional elastomer analysis methods (e.g. ¹ H NMR analysis) to determine the molar extent of grafting.

According to one embodiment of the process for preparing the modified elastomer, the grafting of the compound of formula (I), in particular of the compound of formula (Ib), more in particular of the compound of formula (III), can be carried out in bulk, for example in an extruder, in an internal mixer or in an open mixer, for example in an open mill, or in solution.

According to another preferred embodiment, the process for preparing the modified elastomer can be carried out continuously or batchwise in solution. The elastomer thus obtained by grafting 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.

The subject of the present invention is also a composition comprising at least one modified elastomer obtained by grafting a compound of formula (I) as described above, preferably a compound of formula (Ib), even more preferably a compound of formula (III), and at least one additive.

Additives that can be used in the composition according to the invention can be plasticizers (for example plasticizing oils and/or plasticizing resins), fillers (reinforcing or non-reinforcing fillers), pigments, protective agents (for example antiozone waxes, chemical antiozonants, antioxidants), antifatigue agents, reinforcing resins (as described, for example, in patent application WO 02/10269), crosslinking systems (for example based on sulfur and other vulcanizing agents and/or peroxides and/or bismaleimides). Preferably, the additive is a reinforcing filler, more preferably, the additive is an inorganic reinforcing filler, even more preferably, the additive is silica.

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

1. modified elastomer obtained by grafting at least one compound of formula (I) onto at least one unsaturation of the initial elastomer

Wherein:

-E represents a divalent radical C ₅ -C ₁₂ Hydrocarbyl radical, the divalent C ₅ -C ₁₂ The hydrocarbyl group optionally contains one or more heteroatoms;

2. The modified elastomer of embodiment 1, wherein the initial elastomer is a diene elastomer.

3. The modified elastomer of embodiment 2 wherein the diene elastomer is selected from the group consisting of ethylene/propylene/diene monomer copolymers, natural rubber, synthetic polyisoprene, polybutadiene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

4. The modified elastomer of embodiment 2, wherein the diene elastomer is selected from the group consisting of natural rubber, synthetic polyisoprene, isoprene copolymers and mixtures of these elastomers.

5. The modified elastomer of any of the preceding embodiments, 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%.

6. The modified elastomer of any of the preceding embodiments, wherein E represents divalent C ₅ -C ₁₀ Preferably C ₅ -C ₉ More preferably C ₆ -C ₉ Even more preferably C ₇ -C ₉ A hydrocarbyl group.

7. The modified elastomer of any of the preceding embodiments, wherein E represents C ₅ -C ₁₀ Alkanediyl, preferably C ₅ -C ₉ Alkanediyl, more preferably C ₆ -C ₉ Alkanediyl, even more preferably C ₇ -C ₉ An alkanediyl group.

8. The modified elastomer of any of the preceding embodiments, wherein X is ₁ 、X ₂ And X ₃ May be the same or different and is selected from a hydrogen atom, C ₁ -C ₆ Alkyl and C ₆ -C ₁₄ And (4) an aryl group.

9. The modified elastomer of any of the preceding embodiments, wherein X is ₁ 、X ₂ And X ₃ May be the same or different and represents a hydrogen atom, a methyl group, an ethyl group or a phenyl group.

10. The modified elastomer of any of embodiments 1-8, wherein X ₁ 、X ₂ And X ₃ All represent hydrogen atoms.

11. The modified elastomer of any of embodiments 1 to 8, wherein X ₁ And X ₂ Represents a hydrogen atom, X ₃ Represents a phenyl group.

12. The method according to any one of embodiments 1 to 8Wherein X is ₃ Is a hydrogen atom, a group X ₁ And X ₂ May be the same or different and represents a hydrogen atom or a methyl group.

13. The modified elastomer of any of the preceding embodiments, wherein the compound of formula (I) is selected from compounds of formulae (Ia) and (Ib)

Wherein:

of which E, X ₁ 、X ₂ And X ₃ As defined in any one of embodiments 1 to 12, the symbol (.) represents an attachment to (Ia) or to (Ib),

14. The modified elastomer of embodiment 13, wherein the compound of formula (I) is selected from compounds of formulae (Ia) and (Ib), wherein:

-selected from R of formula (Ia) ₁ To R ₅ And a radical of the formula (Ib) selected from R ₁ To R ₇ Represents a group of the following formula (II):

whereinE、X ₁ 、X ₂ And X ₃ As defined in any one of embodiments 1 to 12, the symbol (.) represents an attachment to (Ia) or to (Ib),

formula (Ia) is selected from R ₁ To R ₅ With the exception of one radical representing the radical of formula (II) and the radical of formula (Ib) is selected from R ₁ To R ₇ The six groups other than the one group representing the group of formula (II) may be the same or different and represent, independently of each other, a hydrogen atom or a methyl group.

15. The modified elastomer of any of embodiments 13 and 14, wherein the compound of formula (I) is a compound of formula (Ib).

16. The modified elastomer of any of embodiments 1-8, wherein the compound of formula (I) is a compound of formula (III)

17. A process for preparing a modified elastomer, the process comprising the step of grafting a compound of formula (I) onto an initial elastomer comprising at least one unsaturation by cycloaddition of a nitrile oxide of the compound of formula (I) [3+2] onto the unsaturation,

wherein:

18. The method of preparing a modified elastomer of embodiment 17, wherein the initial elastomer is a diene elastomer.

19. The process for preparing a modified elastomer according to embodiment 18, wherein the diene elastomer is selected from ethylene/propylene/diene monomer copolymers, natural rubber, synthetic polyisoprene, polybutadiene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

20. The method of preparing a modified elastomer according to embodiment 18, wherein the diene elastomer is selected from the group consisting of natural rubber, synthetic polyisoprene, isoprene copolymers and mixtures of these elastomers.

21. The process for preparing a modified elastomer according to any of embodiments 17 to 20, 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%.

22. The method of preparing a modified elastomer of any of embodiments 17-21, wherein E represents a divalent C ₅ -C ₁₀ Preferably C ₅ -C ₉ More preferably C ₆ -C ₉ Even more preferably C ₇ -C ₉ A hydrocarbyl group.

23. The method of preparing a modified elastomer of any of embodiments 17 to 22, wherein E represents C ₅ -C ₁₀ Alkanediyl, preferably C ₅ -C ₉ Alkanediyl, more preferably C ₆ -C ₉ Alkanediyl, even more preferably C ₇ -C ₉ An alkanediyl group.

24. The method of making a modified elastomer of any of embodiments 17-23, wherein X ₁ 、X ₂ And X ₃ May be the same or different and is selected from a hydrogen atom, C ₁ -C ₆ Alkyl and C ₆ -C ₁₄ And (4) an aryl group.

25. The method of making a modified elastomer of any of embodiments 17-24, wherein X ₁ 、X ₂ And X ₃ Can be the same as orDifferent from each other, and represents a hydrogen atom, a methyl group, an ethyl group or a phenyl group.

26. The method of making a modified elastomer of any of embodiments 17-24, wherein X ₁ 、X ₂ And X ₃ All represent hydrogen atoms.

27. The method of making a modified elastomer of any of embodiments 17-24, wherein X ₁ And X ₂ Represents a hydrogen atom, X ₃ Represents a phenyl group.

28. The method of making a modified elastomer of any of embodiments 17-24, wherein X ₃ Is a hydrogen atom, a group X ₁ And X ₂ May be the same or different and represents a hydrogen atom or a methyl group.

29. The process for preparing a modified elastomer according to any of embodiments 17 to 28, wherein the compound of formula (I) is selected from compounds of formula (Ia) and (Ib)

Wherein:

of which E, X ₁ 、X ₂ And X ₃ As defined in any one of embodiments 17 to 28, the symbol (.) represents an attachment to (Ia) or to (Ib),

30. The process of preparing a modified elastomer according to embodiment 25, wherein the compound of formula (I) is selected from compounds of formulae (Ia) and (Ib), wherein:

31. The process for preparing a modified elastomer according to any of embodiments 29 and 30, wherein the compound of formula (I) is a compound of formula (Ib).

32. The process of preparing a modified elastomer according to any of embodiments 17 to 24, wherein the compound of formula (I) is a compound of formula (III)

33. A composition comprising at least one modified elastomer as defined in any one of embodiments 1 to 16 or a modified elastomer obtained according to the method as defined in any one of embodiments 17 to 32 and at least one additive.

34. The composition according to embodiment 33, wherein the additive is preferably a reinforcing filler, even more preferably a reinforcing mineral filler, even more preferably silica.

Example (b):

the following examples are capable of illustrating the invention; however, the present invention should not be limited to only these examples.

1. Method of producing a composite material

1.1 measurement of the number-average (Mn) molar mass, the weight-average (Mw) molar mass and the polydispersity index of the 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. Various number average molar masses (Mn) and weight average molar masses (Mw) can be determined from commercial standards, and the polydispersity index (PDI = Mw/Mn) can be calculated by "molar" calibration.

Preparation of elastomer samples

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

SEC analysis

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 +1vol% of diisopropylamine +1vol% of triethylamine, or chloroform. The flow rate was 0.7ml/min, the system temperature was 35 ℃ and the analysis time was 90min. A set of four Waters columns in series were used, with the trade names Styragel HMW7, styragel HMW6E and two Styragel HT6E.

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 a commercially available polystyrene standard from the PSS Ready Cal-Kit.

1.2. Characterization of the molecules

Structural analysis and determination of molar purity of the synthesized molecules were performed by NMR analysis. Spectra were collected on a Brucker Avance 3400MHz spectrometer equipped with a "5mm BBFO Z-scale broadband" probe. Quantification of ¹ H NMR experiments used a30 ° simple pulse sequence and a repetition time of 3 seconds between each of the 64 acquisitions. Unless otherwise stated, the samples were dissolved in a deuterated solvent, 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. ¹ H NMR spectra together with 2D ¹ H/ ¹³ C HSQC and ¹ H/ ¹³ the C HMBC experiment enables the determination of the molecular structure (cf. Distribution tables). By quantifying 1D ¹ The H NMR spectrum was subjected to molar quantification.

Mass spectrometry was performed by direct electrospray ionization (DI/ESI). Analysis was performed on a Br ü ker HCT spectrometer (flow rate 600. Mu.l/min, pressure of atomizing gas 10psi, flow rate of atomizing gas 4 l/min).

1.3. Characterization of the Compounds grafted onto the diene elastomer

The determination of the molar content of the compound grafted to the diene elastomer is carried out by NMR analysis. Spectra were collected on a Bru ker MHz spectrometer equipped with a "5mm BBFO Z-grade cryoprobe" probe. Quantification of ¹ H NMR experiments used a simple 30 ° pulse sequence and a repetition time of 5 seconds between each acquisition. The sample was dissolved in deuterated chloroform (CDCl) ₃ ) The purpose is to obtain a "lock" signal. 2D NMR experiments can determine the nature of the grafted units by chemical shift of the carbon atoms and protons.

1.4. Dynamic properties of the rubber composition:

the dynamic properties G and tan (. Delta.) were measured on a viscosity analyzer (Metravib VA 4000) according to the standard ASTM D5992-96 _max . 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 a temperature of 60 ℃ were recorded ² Cylindrical sample of (d). From 0.1% to 100% peak to peakThe strain amplitude scan was then performed from 100% to 0.1% peak-to-peak (reverse cycle).

The result used was the complex dynamic shear modulus at 25% strain, G (G;) _{25% return} ) The dynamic loss factor tan (δ) at 60 ℃ and the difference in modulus (Δ G) between the values at 0.1% and 100% strain (Payne effect). For the return, the value of the complex dynamic shear modulus G at 25% strain (denoted G x) is recorded _{25% of the mixture returns to 60 DEG C} ) And the maximum value of the observed dynamic loss factor tan (δ) (expressed as tan (δ)) _max60℃ )。

The results are shown in base 100, with the control assigned an arbitrary value of 100, in order to calculate and then compare the tan (. Delta.) of the different samples tested _max60℃ 、G* _{25% of the mixture returns to 60 DEG C} And Δ G.

For tan (delta) _max60℃ The value of the sample based on 100 is calculated according to the following calculation: (tan (. Delta.) of the sample) _max60℃ Tan (delta) value/control _max60℃ Value) × 100. In this way, a result of less than 100 indicates a decrease in hysteresis, which corresponds to an improvement in rolling resistance performance.

For G _{25% of the mixture returns to 60 DEG C} The value of the sample based on 100 is calculated according to the following calculation: (G of the sample;) _{25% of the mixture returns to 60 DEG C} value/G of control _{25% of the mixture returns to 60 DEG C} Value) × 100. In this way, results greater than 100 indicate a complex dynamic shear modulus G _{25% of the mixture returns to 60 DEG C} Which demonstrates an improvement in material stiffness.

For (Δ G), the value of the sample based on 100 was calculated according to the following operation: (Δ G value of sample/Δ G value of control) × 100. In this way, a result of less than 100 indicates a decrease in the modulus difference, i.e., an increase in the linearization of the rubber composition.

1.6. Tensile test

These tensile tests enable determination of the elastic stress. Unless otherwise stated, these tensile tests were performed according to French Standard NF T46-002, 9 months 1988. Handling tensile test records also allows the modulus to be plotted as a function of elongation. At the first elongation, the nominal secant modulus (or apparent stress in MPa) calculated with respect to the initial cross section of the specimen is measured at 100% elongation (denoted MSA 100) and 300% elongation (denoted MSA 300). All these tensile test measurements were performed under standard temperature conditions (23. + -. 2 ℃ C.) according to standard NF T46-002.

The MSA300/MSA100 ratio is the enhancement index. The sample 100-based value was calculated according to the following operation: (MSA 300/MSA100 value of sample/MSA 300/MSA100 value of control). Times.100. In this way, results greater than 100 indicate an improvement in the enhancement index.

2. Synthesis of Compounds

2.1. Synthesis of Compound A: 2- ((9-Oxiran-2-yl) nonyl) oxy) -1-naphthacenitrile oxide

Compound F was synthesized according to the following reaction scheme:

11-bromo-1-undecene, 3-chloroperbenzoic acid, 2-hydroxy-1-naphthaldehyde, hydroxylamine and trimethylamine are commercially available products. It is available from Sigma-Aldrich.

2.1.1. Step a1: preparation of 2- (9-bromononyl) oxirane

10g of 11-bromo-1-undecene (42.9 mmol) were dissolved in 200ml of CH ₂ Cl ₂ In (1).

11.84g of 3-chloroperbenzoic acid (68.6 mmol, i.e. 1.4 equivalents, MCPBA) are then added in portions over about 15 minutes and the reaction medium is stirred for 15 hours. The white precipitate is filtered off and taken up with CH ₂ Cl ₂ Wash (2 × 20 ml). Then NaHSO at room temperature (20 ℃ C.) ₃ Aqueous solution (400 ml of distilled water 40g of NaHSO ₃ ) The filtrate was stirred for 5 hours in the presence of (c). The organic phase is recovered by decantation and is reacted with NaHCO ₃ (40g) Was reacted for 5 hours with an aqueous solution (400 ml). After separation by decantation, CH is used ₂ Cl ₂ The remaining aqueous phase was extracted. Incorporating organic matterPhase, then using Na ₂ SO ₄ Dried and concentrated under reduced pressure (12 mbar; bath temperature =30 ℃). A yellow oil was obtained (10.613g, 42.90mmol, 99% yield). Molar purity>90％( ¹ H NMR)。

[ Table 1]

/>

Solvent CDCl ₃

2.1.2 step a2: synthesis of 2- ((9- (oxiran-2-yl) nonyl) oxy) -1-naphthaldehyde

2-hydroxy-1-naphthaldehyde (11.05g, 64.2mmol), 2- (9-bromononyl) oxirane (15.99g, 64.2mmol) and K ₂ CO ₃ A suspension of (8.87g, 64.2mmol) in 20ml of N, N-Dimethylformamide (DMF) for 3 hours and stirred at 500rpm (rpm = rpm). The reaction medium is then poured into 250ml of distilled water and extracted with ethyl acetate (4X 60 ml). The organic phases were combined and then evaporated under reduced pressure (bath temperature =40 ℃,10 mbar) to obtain a brown oil (24.95 g). The product was then purified by column chromatography on silica gel and eluted with a 3/1 (v/v) mixture of petroleum ether/ethyl acetate.

The residual yellow oil was pulverized using petroleum ether to crystallize it. The precipitate was filtered off and air-dried. Pale yellow solid was obtained (14.545g, 42.7mmol, 67% yield). Molar purity greater than 97%, ( ¹ H NMR)。

[ Table 2]

/>

Solvent: CDCl ₃

2.1.3 step a3: synthesis of 2- ((9- (oxiran-2-yl) nonyl) oxy) -1-naphthaldehyde oxime

1.521g of hydroxylamine (23.02 mmol, i.e. 1.5 eq) were added to a suspension of 2- ((9- (oxiran-2-yl) nonyl) oxy) -1-naphthaldehyde (5.225g, 15.35mmol) in ethanol (50 ml) at room temperature at 20 ℃. The reaction mixture was stirred for 3 hours; at the end of the reaction, a yellow solid precipitated. Then 30ml of distilled water are added and the medium is stirred again for 10 minutes. The precipitate obtained is filtered off, washed with 2 × 5ml of a distilled water/ethanol (1:1, vol/vol) mixture and then air-dried. A yellow solid was obtained (4.979g, 14.01mol, 91% yield). Molar purity 93%, ( ¹ H NMR)。

[ Table 3]

/>

Solvent: CDCl ₃

2.1.4 step a4: synthesis of 2- ((9- (oxiran-2-yl) nonyl) oxy) -1-naphthacenitrile N-oxide (Compound A)

1.824g of trimethylamine (18.03 mmol) and2.037g of N-chlorosuccinimide (15.25 mmol) was added to 100ml of CHCl 2- ((9- (oxiran-2-yl) nonyl) oxy) -1-naphthaldehyde oxime (4.929g, 13.87mmol) at a temperature of 0-2 ℃ ₃ In the solution of (1). The reaction mixture was stirred cold for 90 minutes. The organic phase was then washed with distilled water (3X 50 ml) and Na was used ₂ SO ₄ Dried and concentrated under reduced pressure (bath temperature =25 ℃; until 2 mbar) to obtain 5.005g of yellow solid. Redissolving the product in a minimum volume of ethyl acetate to obtain a homogeneous solution; petroleum ether was then poured until the first sign of turbidity appeared (also not very clear, preferably indicating the volume to be poured). The solution was filtered on a silica gel column (l =5 cm) while eluting with an ethyl acetate/petroleum ether (1:3, volume/volume) mixture. The permeate was evaporated under reduced pressure (bath temperature =25 ℃; as low as 1 mbar). A yellow solid was obtained with a melting point of 52-53 ℃ (4.593 g,12.99mmol, 94% yield). Molar purity 92%, ( ¹ H NMR)。

[ Table 4]

/>

Solvent: CDCl ₃

2.2.2 Synthesis of 2- (glycidyloxy) -1-naphthonitrile oxide

2- (glycidyloxy) -1-naphthonitrile oxide (compound B) was synthesized according to the procedure described in patent application US 2012/0046418 A1.

3. Preparation of modified diene elastomer

3.1 rubber modified with Compound A

In an open mill (open mixer at 30 ℃ C.) willObtained according to the above-mentioned method ¹ 2- ((9- (oxiran-2-yl) nonyl) oxy) -1-naphthonitrile oxide with an H NMR purity of 96% (811mg, 2.3mmol, i.e. mole fraction of 0.3 mole%) (Compound A) was incorporated into 50g of natural rubber. 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.

¹ H NMR analysis can confirm that the molar degree of grafting is 0.16 mol% and the molar grafting yield is 54%.

3.2 rubber modified with Compound B

In an open mill (open mixer at 30 ℃ C.) will ¹ 2- (glycidyloxy) -1-naphthonitrile oxide (564mg, 2.34mmol, i.e. 0.3 mol% mole fraction) with an H NMR purity of 94 mol% (Compound B) was incorporated into 50g of natural rubber. The mixture was homogenized by 15 inversions. This mixing stage is followed by a heat treatment in a press at a pressure of 10 bar (10 minutes at 120 ℃).

¹ H NMR analysis can determine the molar degree of grafting to be 0.16 mol% and the molar grafting yield to be 54%.

3.3 Synthesis of Polyisoprene modified with Compound A

The purity obtained according to the above-described process (open mixer at 30 ℃) is mixed in an open mill (open mixer) ¹ H NMR) was 96 mol% 2- ((9- (oxiran-2-yl) nonyl) oxy) -1-naphthacenitrile oxide (811 mg;2.3mmol, i.e. a mole fraction of 0.3 mol%) (compound a) was introduced into 50g of synthetic polyisoprene (comprising 99.35% by weight of cis 1,4-isoprene units and 0.65% by weight of 3,4-isoprene units; mn =375000g/mol and PDI =3.6, measured according to the method described above). 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.

¹ H NMR analysis can confirm that the molar degree of grafting is 0.22 mol% and the molar grafting yield is 74%.

3.4 Synthesis of Polyisoprene modified with Compound B

Purity (C) in an open mill (open mixer at 30 ℃) ( ¹ H NMR) 94 mol% 2- (glycidyloxy) -1-naphthonitrile oxide (564 mg;2.34mmol, i.e. a mole fraction of 0.3 mol%) (compound B) was introduced into 50g of synthetic polyisoprene (comprising 99.35 wt% of cis 1,4-isoprene units and 0.65 wt% of 3,4-isoprene units; mn =375000g/mol and PDI =3.6, measured according to the method described above). The mixture was homogenized by 15 inversions. This mixing stage is followed by a heat treatment in a press at a pressure of 10 bar (10 minutes at 120 ℃).

4. Ingredients used in rubber compositions

(1) Silica, zeosil 1165MP sold by Solvay;

(2) Bis [3- (triethoxysilyl) propyl ] tetrasulfide (TESPT) silane sold by Evonik under reference number Si 69;

(3) Grade N234 carbon black sold by Cabot Corporation;

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

(5) 2,2,4-trimethyl-1,2-dihydroquinoline sold by the company Flexsys;

(6) Zinc oxide (technical grade) sold by the company umcore;

(7) Stearin Pristerene 4031 sold by the company Uniqema;

(8) N-cyclohexyl-2-benzothiazolesulfenamide sold by Flexsys under the reference Santocure CBS.

(9) Natural rubber modified with compound B obtained according to the method described in section 3.1;

(10) Natural rubber modified with compound a obtained according to the method described in section 3.2;

(11) Synthetic polyisoprene modified with compound B obtained according to the method described in section 3.3;

(12) Synthetic polyisoprene modified with compound a obtained according to the method described in section 3.4.

5. Test 1

The purpose of this test is to show the improvement in the reinforcement of the rubber composition comprising the modified rubber according to the invention (composition C2) with respect to the comparative composition (composition C1).

Table 5 shows the content of the various components of these compositions expressed in phr (parts by weight per hundred parts by weight of elastomer).

[ Table 5]

Compositions C1 and C2 comprise the same number of moles (i.e. 0.3 mole%) of grafted compound a or B.

Compositions C1 and C2 were prepared in the following manner: introducing the natural rubber modified with Compound A or Compound B to 85cm filled to 70% ³ In a Polylab internal mixer, the initial vessel temperature of the internal mixer was about 110 ℃.

Then, for each composition, the reinforcing filler and the agent for coupling the filler with the diene elastomer are introduced, then after kneading for 1 to 2 minutes, the various other ingredients than the vulcanization system are introduced. Thermomechanical working (non-productive phase) is then carried out in one step, which lasts about 5 to 6 minutes in total, until a maximum dripping temperature of 160 ℃ is reached.

The mixture thus obtained is recovered and cooled, then the vulcanization system (sulphur and sulfenamide type accelerator) is added in an open mixer (homogeneous finisher) at 23 ℃ and all the substances are mixed (production stage) for about 5 to 12 minutes.

Subsequently, the composition thus obtained was calendered into the form of a rubber sheet (having a thickness of 2 to 3 mm) or a rubber sheet to measure physical properties or mechanical properties thereof.

The rubber properties of these compositions were measured after curing at 150 ℃ for 60 minutes. The results obtained are given in table 6.

[ Table 6]

Composition comprising a fatty acid ester and a fatty acid ester	C1	C2
			MA300/MA100	100	108
ΔG*	100	88
			Tan(δ) _max60℃	100	88
G* _{25% of the mixture returns to 60 DEG C}	100	104

The rubber composition C2 of the invention shows a significant improvement in the hysteresis properties with respect to the comparative composition C1, while also showing an increase in the linearization (Δ G) and an improvement in the reinforcement index (MA 300/M100). Surprisingly, this significant improvement in hysteresis did not reduce the bake stiffness properties. Conversely, the bake stiffness properties were even improved relative to the comparative compositions.

5. Test 2

The aim of this test was to show the improvement in the reinforcement of the rubber composition comprising the modified synthetic polyisoprene according to the invention (composition C4) with respect to the comparative composition (composition C3).

Table 7 shows the content of the various components of these compositions expressed in phr (parts by weight per hundred parts by weight of elastomer).

[ Table 7]

	C3	C4
			Diene elastomer (11) modified with Compound B	100	-
Diene elastomer (12) modified with Compound A	-	100
			Reinforcing filler (1)	55	55
Coupling agent (2)	5.5	5.5
			Carbon black (3)	3	3
Antioxidant (4)	1.5	1.5
			TMQ(5)	1	1
Paraffin wax	1	1
			ZnO(6)	2.7	2.7
Stearic acid (7)	2.5	2.5
			CBS(8)	1.8	1.8
Sulfur	1.5	1.5

Compositions C3 and C4 comprise the same number of moles (i.e. 0.3 mole%) of grafted compound a or B.

Compositions C3 and C4 were prepared according to the method described above for compositions C1 and C2.

The rubber properties of these compositions were measured after curing at 150 ℃ for 60 minutes. The results obtained are given in table 8.

[ Table 8]

Composition comprising a metal oxide and a metal oxide	C3	C4
			MA300/MA100	100	110
ΔG*	100	83
			Tan(δ) _max60℃	100	82
G* _{25% of the mixture returns to 60 DEG C}	100	105

The rubber composition C4 of the invention shows a significant improvement in the hysteresis properties with respect to the comparative composition C3, while also showing an increase in the linearization (Δ G) and an improvement in the reinforcement index (MA 300/M100). Surprisingly, this significant improvement in hysteresis did not reduce the bake stiffness properties. Conversely, the bake stiffness properties were even improved relative to the comparative compositions.

Claims

1. Modified elastomer obtained by grafting at least one compound of formula (I) onto at least one unsaturation of the initial elastomer,

wherein:

2. The modified elastomer of claim 1, wherein the initial elastomer is a diene elastomer.

3. The modified elastomer of claim 2 wherein the diene elastomer is selected from the group consisting of ethylene/propylene/diene monomer copolymers, natural rubber, synthetic polyisoprene, polybutadiene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

4. Modified elastomer according to any of the preceding claims, 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%.

5. The modified elastomer of any preceding claim, wherein E represents a divalent C ₅ -C ₁₀ Preferably C ₅ -C ₉ More preferably C ₆ -C ₉ Even more preferably C ₇ -C ₉ A hydrocarbyl group.

6. The modified elastomer of any preceding claim, wherein E represents C ₅ -C ₁₀ Alkanediyl, preferably C ₅ -C ₉ Alkanediyl, more preferably C ₆ -C ₉ Alkanediyl, even more preferably C ₇ -C ₉ An alkanediyl group.

7. The modified elastomer of any preceding claim, wherein X is ₁ 、X ₂ And X ₃ May be the same or different and is selected from a hydrogen atom, C ₁ -C ₆ Alkyl and C ₆ -C ₁₄ And (4) an aryl group.

8. The modified elastomer of any preceding claim, wherein X is ₁ 、X ₂ And X ₃ All represent hydrogen atoms.

9. The modified elastomer of any one of claims 1 to 6, wherein X is ₁ And X ₂ Represents a hydrogen atom, X ₃ Represents a phenyl group.

10. The modified elastomer of any one of claims 1 to 6, wherein X ₃ Is a hydrogen atom, a group X ₁ And X ₂ May be the same or different and represents a hydrogen atom or a methyl group.

11. Modified elastomer according to any preceding claim, wherein the compound of formula (I) is selected from compounds of formulae (Ia) and (Ib)

Wherein:

-R of formula (Ia) ₁ To R ₅ And a radical of the formula (Ib) selected from R ₁ To R ₇ A group represented byA group of the following formula (II):

of which E, X ₁ 、X ₂ And X ₃ The symbol (.) as defined in any one of claims 1 to 10, denotes attached to (Ia) or attached to (Ib),

12. The modified elastomer of any one of claims 1 to 8, wherein the compound of formula (I) is a compound of formula (III)

13. A process for preparing a modified elastomer, the process comprising the step of grafting a compound of formula (I) onto an initial elastomer comprising at least one unsaturation by a [3+2] cycloaddition of a nitrile oxide of the compound of formula (I) onto the unsaturation,

wherein:

14. The process for preparing a modified elastomer according to claim 13, wherein the compound of formula (I) is a compound of formula (III)

15. A composition comprising at least one modified elastomer as defined in any one of claims 1 to 12 and at least one additive.