Polymers functionalized with imine compounds containing a protected thiol group

1. A method for preparing a functionalized polymer, the method comprising the steps of:

(i) polymerizing monomer to form a reactive polymer, and

(ii) reacting the reactive polymer with an imine compound containing a protected thiol group.

2. The method of claim 1 , where the imine compound containing a protected thiol group is defined by the formula I:

where R 1 is a hydrogen atom or a monovalent organic group, R 2 is a bond or a divalent organic group, R 3 is a monovalent organic group, and R 4 is a hydrolyzable group, or where R 1 and R 2 join to form a trivalent organic group, or where R 1 and R 3 join to form a divalent organic group.

3. The method of claim 2 , where R 4 is a silyl group.

4. The method of claim 3 , where the silyl group is selected from trihydrocarbylsilyl, dihydrocarbylhydrosilyl, and hydrocarbyldihydrosilyl groups.

5. The method of claim 2 , where R 4 is a silyl group selected from trihydrocarbylsilyl, dihydrocarbylhydrosilyl, and hydrocarbyldihydrosilyl groups.

6. The method of claim 1 , where the imine compound containing a protected thiol group is defined by the formula II:

where R 4 is a hydrolyzable group, R 5 and R 6 are each independently a hydrogen atom or a monovalent organic group, and R 2 is a bond or a divalent organic group, or where R 5 and R 6 join to form a divalent organic group, or where R 2 and R 5 join to form a trivalent organic group.

7. The method of claim 1 , where the imine compound containing a protected thiol group is defined by the formula III:

where R 3 is a monovalent organic group, R 4 is a hydrolyzable group, and R 7 is a trivalent organic group.

8. The method of claim 1 , where the imine compound containing a protected thiol group is defined by the formula IV:

where R 2 is a bond or a divalent organic group, R 4 is a hydrolyzable group, and R 8 is a divalent organic group.

9. The method of claim 1 , where the imine compound containing a protected thiol group is defined by the formula V:

where R 2 is a bond or a divalent organic group, R 4 is a hydrolyzable group, and R 10 is a divalent organic group.

10. The method of claim 1 , where the imine compound containing a protected thiol group is defined by the formula VI:

where R 1 is a hydrogen atom or a monovalent organic group, R 2 is a bond or a divalent organic group, R 3 is a monovalent organic group, and each R 9 is individually a hydrogen atom or a monovalent organic group, or where R 1 and R 2 join to form a trivalent organic group, or where R 1 and R 3 join to form a divalent organic group.

11. The method of claim 1 , where the imine compound containing a protected thiol group is defined by the formula VII:

where R 2 is a bond or a divalent organic group, R 5 and R 6 are each independently a hydrogen atom or a monovalent organic group, and each R 9 is individually a hydrogen atom or a monovalent organic group, or where R 5 and R 6 join to form a divalent organic group, or where R 2 and R 5 join to form a trivalent organic group.

12. The method of claim 1 , where the imine compound containing a protected thiol group is defined by the formula VIII:

where R 3 is a monovalent organic group, R 7 is a trivalent organic group, and each R 9 is individually a hydrogen atom or a monovalent organic group.

13. The method of claim 1 , where the imine compound containing a protected thiol group is defined by the formula IX:

where R 2 is a bond or a divalent organic group, R 8 is a divalent organic group, and each R 9 is individually a hydrogen atom or a monovalent organic group.

14. The method of claim 1 , where the imine compound containing a protected thiol group is defined by the formula X:

where R 2 is a bond or a divalent organic group, each R 9 is individually a hydrogen atom or a monovalent organic group, and R 10 is a divalent organic group.

15. The method of claim 1 , where the imine compound containing a protected thiol group is an N-(silylthiohydrocarbylidene) hydrocarbylamine, N-hydrocarbylidene (silylthiohydrocarbyl)amine, N-(silylthiocyclohydrocarbylidene)hydrocarbylamine, or N-cyclohydrocarbylidene (silylthiohydrocarbyl)amine.

16. The method of claim 15 , where the imine compound containing a protected thiol group is an N-(silylthiohydrocarbylidene)hydrocarbylamine selected from the group consisting of N-[α-(silylthioaryl) hydrocarbylidene]arylamine, N-(silylthioalkylidene)alkylamine, N-[α-(silylthioaryl) hydrocarbylidene]alkylamine, and N-(silylthioalkylidene) arylamine.

17. The method of claim 15 , where the imine compound containing a protected thiol group is an N-hydrocarbylidene(silylthiohydrocarbyl)amine selected from the group consisting of N-(α-arylhydrocarbylidene)(silylthioaryl)amine, N-alkylidene (silylthioalkyl)amine, N-(α-arylhydrocarbylidene)(silylthioalkyl)amine, and N-alkylidene(silylthioaryl)amine.

18. The method of claim 15 , where the imine compound containing a protected thiol group is an N-(silylthiocyclohydrocarbylidene)hydrocarbylamine selected from the group consisting of N-(silylthiocyclohydrocarbylidene)alkylamine, and N-(silylthiocyclohydrocarbylidene) arylamine.

19. The method of claim 15 , where the imine compound containing a protected thiol group is an N-cyclohydrocarbylidene(silylthiohydrocarbyl)amine selected from the group consisting of N-cyclohydrocarbylidene(silylthioalkyl)amine, and N-cyclohydrocarbylidene (silylthioaryl)amine.

20. The method of claim 1 , where the monomer includes conjugated diene monomer.

21. The method of claim 20 , where said step of polymerizing employs a coordination catalyst.

22. The method of claim 21 , where the coordination catalyst is a lanthanide-based catalyst.

23. The method of claim 22 , where the lanthanide-based catalyst includes (a) a lanthanide-containing compound, (b) an alkylating agent, and (c) a halogen source.

24. The method of claim 23 , where the alkylating agent includes an aluminoxane and an organoaluminum compound represented by the formula AlR n X 3-n , where each R, which may be the same or different, is a monovalent organic group that is attached to the aluminum atom via a carbon atom, where each X, which may be the same or different, is a hydrogen atom, a halogen atom, a carboxylate group, an alkoxide group, or an aryloxide group, and where n is an integer of 1 to 3.

25. The method of claim 22 , where said step of polymerizing monomer takes place within a polymerization mixture including less than 20% by weight of organic solvent.

26. The method of claim 20 , where said step of polymerizing employs an anionic initiator.

27. The method of claim 26 , where the anionic initiator is an organolithium compound.

28. A method for preparing a functionalized polymer, the method comprising the steps of:

(i) polymerizing conjugated diene monomer, and optionally monomer copolymerizable therewith, to form a polymer having a reactive chain end; and

(ii) reacting the reactive chain end of the polymer with an imine compound containing a protected thiol group.

29. The method of claim 28 , where said step of polymerizing employs a coordination catalyst or an anionic initiator.

30. A functionalized polymer prepared by the steps of:

(i) polymerizing conjugated diene monomer, and optionally monomer copolymerizable therewith, to form a polymer having a reactive chain end; and

(ii) reacting the reactive chain end of the polymer with an imine compound containing a protected thiol group.

31. A tire component prepared by employing the functionalized polymer of claim 30 .

32. A vulcanizable composition comprising:

the functionalized polymer of claim 30 , a filler, and a curative.