Process for preparing a diene copolymer comprising a polyether block, diene copolymer comprising a polyether block, reinforced rubber composition and tire

1. A process for preparing a diene block copolymer, of which at least one of said blocks is constituted of a diene elastomer and at least the other of said blocks is constituted of a polyether, wherein the process comprises a step of reacting a living diene elastomer with a functionalizing agent having a functional polyether block of number-average molecular weight from 150 to 5000 g/mol, represented by general formula I:

R 1 A) m   Formula I

in which:

R 1 represents a C 1 -C 15 alkyl, C 6 -C 15 aryl or C 7 -C 15 aralkyl hydrocarbon-based derivative of valency m;

m is an integer from 1 to 4; and

A represents, identically or differently when m is greater than 1, the group of general formula II

in which:

R 2 represents a C 1 -C 10 alkylene radical;

R 3 represents a divalent hydrocarbon derivative from C 1 -C 50 alkyl, C 6 -C 50 aryl or C 7 -C 50 aralkyl hydrocarbon-based derivative;

R 4 represents a C 1 -C 50 alkyl, C 6 -C 50 aryl or C 7 -C 50 aralkyl radical;

X represents, identically or differently when i is equal to 0 or 1, a group chosen from a halogen atom and a group of formula —OR 5 in which R 5 represents a C 1 -C 18 alkyl, C 5 -C 18 cycloalkoxyl or C 6 -C 18 aryl radical;

n is a number greater than 1, so that the polyether block has a number-average molecular weight from 150 to 5000 g/mol; and

i is an integer from 0 to 2.

2. The process according to claim 1 , wherein in the general formula I, m is equal to 1 or 2.

3. The process according to claim 1 , wherein in the general formula I, R 2 represents the

radical, in which R 6 and R 7 are, independently of one another, a hydrogen atom or a C 1 -C 4 alkyl radical.

4. The process according to claim 3 , wherein in the general formula I, R 2 represents the ethylene radical.

5. The process according to claim 1 , wherein in the general formula I, R 3 represents the propane-1,3-diyl radical.

6. The process according to claim 1 , wherein in the general formula I, i is equal to 0 or 1.

7. The process according to claim 1 , wherein prior to the step of reacting the living diene elastomer with the functionalizing agent of general formula I, the process comprises a step of preparing the living diene elastomer by anionic polymerization of at least one diene monomer in the presence of a monofunctional organometallic initiator.

8. The process according to claim 1 , wherein prior to the step of reacting the living diene elastomer with the functionalizing agent of general formula I, the process comprises a step of intermediate functionalization of the living polymer by reaction of the latter with a cyclic organosiloxane compound to form a silanolate-terminated living diene elastomer, and wherein the prefunctionalized elastomer then reacts with the functionalizing agent of general formula I.

9. The process according to claim 1 , wherein the step of reacting the living diene elastomer with the functionalizing agent of general formula I is followed by a hydrolysis or alcoholysis step.

10. The process according to claim 1 , wherein the process comprises a step of coupling and/or of star-branching and/or else of supplementary functionalization with a functionalizing agent other than a cyclic organosiloxane compound and different from that of general formula I.

11. A diene block copolymer, comprising at least one polyether block of number-average molecular weight from 150 to 5000 g/mol, and corresponds to the general formula III:

R 1 A′) m   Formula III

in which:

R 1 represents a C 1 -C 15 alkyl, C 6 -C 15 aryl or C 7 -C 15 alkylaryl hydrocarbon-based derivative of valency m;

m is an integer from 1 to 4; and

A′ represents, identically or differently when m is other than 1, the block of general formula IV:

in which:

R 2 represents a C 1 -C 10 alkylene radical;

R 3 represents a divalent hydrocarbon derivative from C 1 -C 50 alkyl, C 6 -C 50 aryl or C 7 -C 50 aralkyl hydrocarbon-based derivative;

R 4 represents, independently of one another, a C 1 -C 50 alkyl, C 6 -C 50 aryl or C 7 -C 50 aralkyl radical;

R 8 represents a hydrogen atom or a C 1 -C 18 alkyl, C 5 -C 18 cycloalkoxyl or C 6 -C 18 aryl radical;

n is a number greater than 1, so that the polyether block has a number-average molecular weight of 150 to 5000 g/mol;

i is an integer from 0 to 2;

k is an integer from 1 to 3, such that i+k≦3; and

B represents the —[(—O—SiR 9 R 10 ) q —P] group, in which R 9 and R 10 represent, independently of one another, a C 1 -C 50 alkyl, C 6 -C 50 aryl or C 1 -C 50 aralkyl radical, q is an integer from 0 to 10, and P is a diene elastomer.

12. The diene block copolymer according to claim 11 , wherein in the general formulae III and IV, R 1 , R 2 , R 3 , m and i are, independently of one another, as defined in claim 2 .

13. The diene block copolymer according to claim 11 , wherein in the general formulae III and IV, m is equal to 1 and k is equal to 2.

14. The diene block copolymer according to claim 11 , wherein in the general formulae III and IV, m is equal to 2 and k is equal to 1.

15. The diene block copolymer according to claim 11 , wherein in the general formula IV, i+k is equal to 1 or 2.

16. The diene block copolymer according to claim 11 , wherein in the general formula IV, R 8 represents a methyl or ethyl radical or a hydrogen atom.

17. The diene block copolymer according to claim 11 , wherein in the general formula IV, q is not zero, preferably equal to 1.

18. The diene block copolymer according to claim 11 , wherein in the general formula IV, the diene elastomer P is a styrene/butadiene copolymer.

19. A reinforced rubber composition, that can be used for the manufacture of a pneumatic tire, based on at least one diene block copolymer as defined in claim 11 , which is adapted to interact with a reinforcing filler.

20. The rubber composition according to claim 19 , comprising predominantly a reinforcing inorganic filler as a reinforcing filler.

21. The rubber composition according to claim 20 , wherein the reinforcing filler is constituted by the reinforcing inorganic filler.

22. The rubber composition according to claim 20 , wherein the reinforcing inorganic filler is silica.

23. The rubber composition according to claim 19 , wherein the reinforcing filler comprises carbon black.

24. The rubber composition according to claim 19 , comprising, as a blend with said diene block copolymer, at least one of the polymers chosen from natural rubber, synthetic diene elastomers, synthetic diene elastomers that are coupled and/or star-branched and/or else partially or completely functionalized by a functionalizing agent different from that represented by general formula I:

R 1 A) m   Formula I

in which:

R 1 represents a C 1 -C 15 alkyl, C 6 -C 15 aryl or C 7 -C 15 aralkyl hydrocarbon-based derivative of valency m;

m is an integer from 1 to 4; and

A represents, identically or differently when m is greater than 1, the group of general formula II

in which:

R 2 represents a C 1 -C 10 alkylene radical;

R 3 represents a divalent hydrocarbon derivative from C 1 -C 50 alkyl, C 6 -C 50 aryl or C 7 -C 50 aralkyl hydrocarbon-based derivative;

R 4 represents a C 1 -C 50 alkyl, C 6 -C 50 aryl or C 7 -C 50 aralkyl radical;

X represents, identically or differently when i is equal to 0 or 1, a group chosen from a halogen atom and a group of formula —OR 5 in which R 5 represents a C 1 -C 18 alkyl, C 5 -C 18 cycloalkoxyl or C 6 -C 18 aryl radical;

n is a number greater than 1, so that the polyether block has a number-average molecular weight from 150 to 5000 g/mol; and

i is an integer from 0 to 2,

and synthetic elastomers other than diene elastomers.

25. A tire incorporating, in at least one of its constituent components, a rubber composition according to claim 19 .

26. A tread for a tire, incorporating, in at least one of its constituent components, a rubber composition according to claim 19 .