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US-12617939-B2 - Functional ethylene and 1,3-diene copolymers

US12617939B2US 12617939 B2US12617939 B2US 12617939B2US-12617939-B2

Abstract

A copolymer of ethylene and of a 1,3-diene of formula CH 2 ═CR—CH═CH 2 , which copolymer bears a silanol or alkoxysilane function, the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms, is provided. Such a copolymer improves the compromise between the content of ethylene in the polymer, its crystallinity and the stiffness of a rubber composition containing it.

Inventors

  • Emma MORESO
  • Vincent LAFAQUIERE

Assignees

  • COMPAGNIE GENERALE DES ETABLISSEMENTS MICHELIN

Dates

Publication Date
20260505
Application Date
20200917
Priority Date
20190918

Claims (19)

  1. 1 . A copolymer of ethylene and of a 1,3-diene of formula (I), which copolymer bears a silanol or alkoxysilane function, CH 2 ═CR—CH═CH 2 (I) the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms, which copolymer contains units of the 1,3-diene of 1,2 or 3,4 configuration, the group consisting of units of the 1,3-diene of 1,2 configuration and units of the 1,3-diene of 3,4 configuration representing more than 50 mol % of the units of the 1,3-diene.
  2. 2 . A copolymer consisting of ethylene and of a 1,3-diene of formula (I), which copolymer bears a silanol or alkoxysilane function, CH 2 ═CR—CH═CH 2 (I) the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms, and in which the copolymer is a statistical copolymer.
  3. 3 . The copolymer according to claim 2 , in which the silanol or alkoxysilane function is at the chain end of the copolymer.
  4. 4 . The copolymer according to claim 2 , which copolymer contains more than 50 mol % of ethylene units.
  5. 5 . The copolymer according to claim 2 , which copolymer contains at most 90 mol % of ethylene units.
  6. 6 . The copolymer according to claim 2 , in which the symbol R represents an aliphatic chain.
  7. 7 . The copolymer according to claim 2 , in which the symbol R represents a hydrocarbon chain having from 6 to 16 carbon atoms.
  8. 8 . The copolymer according to claim 2 , in which the symbol R represents an acyclic chain.
  9. 9 . The copolymer according to claim 2 , in which the symbol R represents a linear or branched chain.
  10. 10 . The copolymer according to claim 2 , in which the 1,3-diene is myrcene or β-farnesene.
  11. 11 . The copolymer according to claim 2 , which copolymer has a glass transition temperature below −35° C.
  12. 12 . The copolymer according to claim 11 , wherein the glass transition temperature is between −90° C. and −35° C.
  13. 13 . A rubber composition which comprises a copolymer defined according to claim 2 , a reinforcing inorganic filler, and a crosslinking system, which copolymer is an elastomer.
  14. 14 . The rubber composition according to claim 13 , wherein the reinforcing inorganic filler is a silica.
  15. 15 . A tire which comprises a rubber composition defined according to claim 13 .
  16. 16 . A process for preparing a copolymer defined according to claim 2 , which process comprises the following steps: (a) the copolymerization of ethylene and of a 1,3-diene of formula (I) in the presence of a catalytic system comprising a metallocene of formula (II) and an organomagnesium compound of formula (III) CH 2 ═CR—CH═CH 2 (I), P(Cp 1 Cp 2 )Nd(BH 4 ) (1+y) -L y -N x (II) MgR 1 R 2 (III) the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms, Cp 1 and Cp 2 , which may be identical or different, being selected from the group consisting of the cyclopentadienyl group of formula C 5 H 4 , the unsubstituted fluorenyl group of formula C 13 H 8 and substituted fluorenyl groups, P being a group bridging the two Cp 1 and Cp 2 groups and representing a ZR 3 R 4 group, Z representing a silicon or carbon atom, R 3 and R 4 , which are identical or different, each representing an alkyl group comprising from 1 to 20 carbon atoms, y, which is an integer, being equal to or greater than 0, x, which may or may not be an integer, being equal to or greater than 0, L representing an alkali metal selected from the group consisting of lithium, sodium and potassium, N representing a molecule of an ether, R 1 and R 2 , which are identical or different, representing a carbon group, (b) the reaction of a functionalizing agent, compound of formula (IV), with the copolymer obtained in step a), Si(FC 1 ) 4-g (Rc 2 ) g (IV) the Fc 1 symbols, which may be identical or different, representing an alkoxy group or a halogen atom, the Rc 2 symbols, which may be identical or different, representing a hydrogen atom, a hydrocarbon chain or a hydrocarbon chain substituted by a chemical function Fc 2 , g being an integer ranging from 0 to 2, (c) where appropriate, a hydrolysis reaction.
  17. 17 . A process according to claim 16 , in which the functionalizing agent is dimethoxydimethylsilane, diethoxydimethylsilane, dimethoxydiethylsilane, diethoxydiethylsilane, (N,N-dimethyl-3-aminopropyl)methyldimethoxysilane, (N,N-dimethyl-3-aminopropyl)methyldiethoxysilane, (N,N-dimethyl-3-aminopropyl)ethyldimethoxysilane, (N,N-dimethyl-3-aminopropyl)ethyldiethoxysilane, 3-methoxy-3,8,8,9,9-pentamethyl-2-oxa-7-thia-3,8-disiladecane, trimethoxymethylsilane, triethoxymethylsilane, trimethoxyethylsilane, triethoxyethylsilane, (N,N-dimethylaminopropyl)trimethoxysilane, (N,N-dimethylaminopropyl)triethoxysilane, (N-(3-trimethoxysilyl)propyl)-N-(trimethylsilyl)silanamine, (N-(3-triethoxysilyl)propyl)-N-(trimethylsilyl)silanamine or 3,3-dimethoxy-8,8,9,9-tetramethyl-2-oxa-7-thia-3,8-disiladecane.
  18. 18 . A process for preparing a copolymer defined according to claim 2 , which process comprises the following steps: (a) the copolymerization of ethylene and of a 1,3-diene of formula (I) in the presence of a catalytic system comprising a metallocene of formula (II) and an organomagnesium compound of formula (III) CH 2 ═CR—CH═CH 2 (I), P(Cp 1 Cp 2 )Nd(BH 4 ) (1+y) -L y -N x (II) MgR 1 R 2 (III) the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms, Cp 1 and Cp 2 , which may be identical or different, being selected from the group consisting of the cyclopentadienyl group of formula C 5 H 4 , the unsubstituted fluorenyl group of formula C 13 H 8 and substituted fluorenyl groups, P being a group bridging the two Cp 1 and Cp 2 groups and representing a ZR 3 R 4 group, Z representing a silicon or carbon atom, R 3 and R 4 , which are identical or different, each representing an alkyl group comprising from 1 to 20 carbon atoms, y, which is an integer, being equal to or greater than 0, x, which may or may not be an integer, being equal to or greater than 0, L representing an alkali metal selected from the group consisting of lithium, sodium and potassium, N representing a molecule of an ether, R 1 and R 2 , which are identical or different, representing a carbon group, (b) the reaction of a functionalizing agent, compound of formula (IV), with the copolymer obtained in step a), Si(FC 1 ) 4-g (Rc 2 ) g (IV) the Fc 1 symbols, which may be identical or different, representing an alkoxy group or a halogen atom, the Rc 2 symbols, which may be identical or different, representing a hydrogen atom, a hydrocarbon chain or a hydrocarbon chain substituted by a chemical function Fc 2 , g being an integer ranging from 0 to 2, (c) where appropriate, a hydrolysis reaction, wherein R 3 and R 4 each represent a methyl and N represents diethyl ether or tetrahydrofuran.
  19. 19 . A process for preparing a copolymer defined according to claim 2 , which process comprises the following steps: (a) the copolymerization of ethylene and of a 1,3-diene of formula (I) in the presence of a catalytic system comprising a metallocene of formula (II) and an organomagnesium compound of formula (III) CH 2 ═CR—CH═CH 2 (I), P(Cp 1 Cp 2 )Nd(BH 4 ) (1+y) -L y -N x (II) MgR 1 R 2 (III) the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms, Cp 1 and Cp 2 , which may be identical or different, being selected from the group consisting of the cyclopentadienyl group of formula C 5 H 4 , the unsubstituted fluorenyl group of formula C 13 H 8 and substituted fluorenyl groups, P being a group bridging the two Cp 1 and Cp 2 groups and representing a ZR 3 R 4 group, Z representing a silicon or carbon atom, R 3 and R 4 , which are identical or different, each representing an alkyl group comprising from 1 to 20 carbon atoms, y, which is an integer, being equal to or greater than 0, x, which may or may not be an integer, being equal to or greater than 0, L representing an alkali metal selected from the group consisting of lithium, sodium and potassium, N representing a molecule of an ether, R 1 and R 2 , which are identical or different, representing a carbon group, (b) the reaction of a functionalizing agent, compound of formula (IV), with the copolymer obtained in step a), Si(FC 1 ) 4-g (Rc 2 ) g (IV) the Fc 1 symbols, which may be identical or different, representing an alkoxy group or a halogen atom, the Rc 2 symbols, which may be identical or different, representing a hydrogen atom, a hydrocarbon chain or a hydrocarbon chain substituted by a chemical function Fc 2 , g being an integer ranging from 0 to 2, (c) where appropriate, a hydrolysis reaction, in which the functionalizing agent is dimethoxydimethylsilane, diethoxydimethylsilane, dimethoxydiethylsilane, diethoxydiethylsilane, (N,N-dimethyl-3-aminopropyl)methyldimethoxysilane, (N,N-dimethyl-3-aminopropyl)methyldiethoxysilane, (N,N-dimethyl-3-aminopropyl)ethyldimethoxysilane, (N,N-dimethyl-3-aminopropyl)ethyldiethoxysilane, 3-methoxy-3,8,8,9,9-pentamethyl-2-oxa-7-thia-3,8-disiladecane, trimethoxymethylsilane, triethoxymethylsilane, trimethoxyethylsilane, triethoxyethylsilane, (N,N-dimethylaminopropyl)trimethoxysilane, (N,N-dimethylaminopropyl)triethoxysilane, (N-(3-trimethoxysilyl)propyl)-N-(trimethylsilyl)silanamine, (N-(3-triethoxysilyl)propyl)-N-(trimethylsilyl)silanamine or 3,3-dimethoxy-8,8,9,9-tetramethyl-2-oxa-7-thia-3,8-disiladecane, wherein the functionalizing agent is dimethoxydimethylsilane, dimethoxydiethylsilane, (N,N-dimethyl-3-aminopropyl)methyldimethoxysilane, (N,N-dimethyl-3-aminopropyl)ethyldimethoxysilane, 3-methoxy-3,8,8,9,9-pentamethyl-2-oxa-7-thia-3,8-disiladecane, trimethoxymethylsilane, trimethoxyethylsilane, (N,N-dimethylaminopropyl)trimethoxysilane, (N-(3-trimethoxysilyl)propyl)-N-(trimethylsilyl)silanamine or 3,3-dimethoxy-8,8,9,9-tetramethyl-2-oxa-7-thia-3,8-disiladecane.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This U.S. national phase patent application claims priority to and the benefit of International Patent Application No. PCT/FR2020/051602, filed on Sep. 17, 2020, which claims priority to and the benefit of French patent application no. FR1910304, filed Sep. 18, 2019, the contents of which are incorporated herein by reference in their entirety. BACKGROUND 1. Technical Field The present invention relates to copolymers of ethylene and of 1,3-diene intended to be used in rubber compositions for tires. 2. Related Art The most widely used diene copolymers in the manufacture of tires are polybutadienes, polyisoprenes, in particular natural rubber, and copolymers of 1,3-butadiene and of styrene. It has been proposed, in particular in document WO 2014114607, to use copolymers of ethylene and of 1,3-butadiene in rubber compositions for tires. These copolymers are synthesized by copolymerization of ethylene and 1,3-butadiene in the presence of a catalytic system comprising a rare-earth metallocene. The reinforced rubber compositions of ethylene/1,3-butadiene copolymer are in particular described for use in a tread of a tire. These diene rubber compositions, once crosslinked, exhibit a much higher stiffness than the diene rubber compositions customarily used and may therefore prove unsuitable for certain applications. There is therefore a need to significantly reduce the cured stiffness of such compositions comprising an ethylene-based diene rubber. SUMMARY The applicant has discovered a copolymer which makes it possible to solve the problems mentioned. Thus a first subject of the invention is a copolymer of ethylene and of a 1,3-diene of formula (I), which copolymer bears a silanol or alkoxysilane function, CH2═CR—CH═CH2  (I) the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms. Another subject of the invention is a rubber composition which comprises a copolymer in accordance with the invention, a reinforcing inorganic filler and a crosslinking system, which copolymer is an elastomer. The invention also relates to a tire which comprises a rubber composition in accordance with the invention. The invention also relates to a process for preparing a copolymer in accordance with the invention, which process comprises the following steps: a) the copolymerization of ethylene and of a 1,3-diene of formula (I) in the presence of a catalytic system comprising a metallocene of formula (II) and an organomagnesium compound of formula (III) CH2═CR—CH═CH2  (I), P(Cp1Cp2)Nd(BH4)(1+y)-Ly-Nx  (II) MgR1R2  (III) the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms,Cp1 and Cp2, which may be identical or different, being selected from the group consisting of the cyclopentadienyl group of formula C5H4, the unsubstituted fluorenyl group of formula C13H8 and substituted fluorenyl groups,P being a group bridging the two Cp1 and Cp2 groups and representing a ZR3R4 group, Z representing a silicon or carbon atom, R3 and R4, which are identical or different, each representing an alkyl group comprising from 1 to 20 carbon atoms, preferably a methyl,y, which is an integer, being equal to or greater than 0,x, which may or may not be an integer, being equal to or greater than 0,L representing an alkali metal selected from the group consisting of lithium, sodium and potassium,N representing a molecule of an ether, preferably diethyl ether or tetrahydrofuran,R1 and R2, which may be identical or different, representing a carbon group,b) the reaction of a functionalizing agent, compound of formula (IV), with the copolymer obtained in step a), Si(Fc1)4-g(Rc2)g  (IV) the Fc1 symbols, which may be identical or different, representing an alkoxy group or a halogen atom,the Rc2 symbols, which may be identical or different, representing a hydrogen atom, a hydrocarbon chain or a hydrocarbon chain substituted by a chemical function Fc2,g being an integer ranging from 0 to 2,c) where appropriate, a hydrolysis reaction. DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS Any interval of values denoted by the expression “between a and b” represents the range of values greater than “a” and less than “b” (that is to say limits a and b excluded), whereas any interval of values denoted by the expression “from a to b” means the range of values extending from “a” up to “b” (that is to say including the strict limits a and b). The abbreviation “phr” means parts by weight per hundred parts by weight of elastomer (of the total of the elastomers if several elastomers are present). The expression “based on” used to define the constituents of a catalytic system or of a composition is understood to mean the mixture of these constituents, or the product of the reaction of a portion or of all of these constituents with one another. Unless otherwise indicated, the contents of the units resulting from the insertion of a monomer into a copolymer are expressed as molar percentage with respect to a