Functionalized thermoplastic elastomer

• US 20030158334A1
• Filed: 01/23/2003
• Published: 08/21/2003
• Est. Priority Date: 05/18/1998
• Status: Active Grant

• Current Assignee: Bridget Ann Spence, Robert Charles Job, Ronald James Hoxmeier
• Original Assignee: Bridget Ann Spence, Robert Charles Job, Ronald James Hoxmeier
• Inventors: Spence, Bridget Ann, Job, Robert Charles, Hoxmeier, Ronald James
• Granted Patent: US 6,750,289 B2
• Time in Patent Office: Days
• US Class Current: 525/70
• CPC Class Codes: C08F 255/00 Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00
• CPC Class Codes: C08F 255/02 on to polymers of olefins having two or three carbon atoms
• CPC Class Codes: C08F 255/08 on to polymers of olefins having four or more carbon atoms
• CPC Class Codes: C08F 283/12 on to polysiloxanes

Abstract

A thermoplastic elastomer produced without a hydrogenation step is functionalized utilizing a free radical initiator and a functionalizing monomer having at least one point of unsaturation. The base polymers can be produced by copolymerizing an α-olefin capable of producing an amorphous backbone with a comonomer which provides a “hook” for grafting to with a living polystyrene chain. Another method is to copolymerize an α-olefin monomer system capable of producing an amorphous backbone with a comonomer containing a functional group from which an anionically polymerizable monomer is grown from the backbone. A third method involves copolymerizing an α-olefin monomer system capable of giving an amorphous backbone with an olefin-terminated polystyrene comonomer. In a less preferred embodiment, a conventional EPDM polymer can be metallated and a monoalkenyl aromatic compound anionically polymerizable monomer grown from the backbone.

Claims

1. A process for producing a functionalized saturated thermoplastic elastomer which comprises:

(a) copolymerizing;

(i) a monomer system selected from the group consisting of at least one C₄-C₃₀ α

-olefins and ethylene plus 20 to 40 mole % of a higher α

-olefin with

(ii) a 1-alkenyl comonomer containing a functional group to which a polymer chain formed by anionic polymerization can be grafted to produce a graft block copolymer;

(b) anionically polymerizing at least one monoalkenyl aromatic compound to form living polymer chains;

(c) grafting said living polymer chains onto said block copolymer to form said thermoplastic elastomer, said elastomer having a saturated olefinic backbone with pendant polyarene side chains; and

(d) contacting said thermoplastic elastomer with a free radical initiator and a functionalizing monomer having at least one point of unsaturation.

2. A method according to claim 1 wherein said functionalizing monomer is selected from carboxylic acids and derivatives of carboxylic acids.

3. A method according to claim 2 wherein said monomer system is ethylene and 20-40 mole % propylene.

4. A method according to claim 2 wherein said monomer system is a single monomer selected from hexene and octene.

5. A method according to claim 2 wherein said comonomer is a 1-alkenylhalosilane.

6. A method according to claim 2 wherein said free radical initiator is a peroxide.

7. A method according to claim 2 wherein said copolymerization takes place in the presence of a catalyst comprising Mg(OCH₂CH₃)₁₀TiCl₄(benzaldehyde)₂ with an ethyl aluminum dichloride cocatalyst and an electron donor selected from benzaldehyde and 1,2-diethoxybenzene.

8. A method according to claim 1 wherein said monomer system is selected from hexene and octene, said comonomer is allyldimethylchlorosilane, said living polymer chains are formed from styrene initiated with secondary butyllithium, said free radical initiator is 2,5-dimethyl-2,5-di-(t-butylperoxy)-hexane and said functionalizing monomer is maleic anhydride and said maleic anhydride is incorporated in an amount within the range of 0.2 to 5 weight percent.

9. A product produced by the method of claim 8.

10. A product produced by the method of claim 1.

11. A process for producing a functionalized saturated thermoplastic elastomer which comprises:

(a) copolymerizing;

(i) a monomer system selected from at least one C₄-C₃₀ α

-olefin and ethylene plus 20 to 40 mole percent of a higher α

-olefin with

(ii) a comonomer selected from

and

CH₂═

H—

(CH₂)_n—

SiR_mH_x

wherein R is selected from alkyl and aryl, x is 0-1, m is 2-3 and x+n=3, said comonomer containing a functional group from which an anionically polymerized polymer is grown to produce a graft block copolymer;

(b) metallating said functional group on said comonomer by reaction with an organo-alkali metal compound in the presence of a metallation activator;

(c) reacting the thus metallated copolymer with at least one monoalkenyl aromatic compound to form a thermoplastic elastomer having a saturated olefinic backbone with pendant anionically polymerized monoalkenyl aromatic compound side chains; and

(d) contacting said thermoplastic elastomer with a free radical initiator and a functionalizing monomer having at least one point of unsaturation.

12. A process according to claim 11 wherein said copolymerizing is done using a catalyst formed from Mg₆(OCH₂CH₃)₁₀TiCl₄(benzaldehyde)₂ with a triethylaluminum cocatalyst and treated with a composition selected from the group consisting of benzaldehyde and 1,2-diethoxybenzene.

13. A method according to claim 11 wherein said comonomer is allyltrimethyl silane.

14. A method according to claim 11 wherein said monomer system is a single monomer selected from hexene and octene, said comonomer is selected from allylbenzene and 4-phenyl-1-butene, said metallating is done with sec-butyllithium, said metallation activator is N,N,N′

,N′

-tetramethylethylenediamine, said monoalkenyl aromatic compound is styrene, said free radical initiator is a peroxide and said functionalizing monomer is maleic anhydride said maleic anhydride being incorporated in an amount within the range of 0.2 to 5 weight percent.

15. A product produced by the method of claim 14.

16. A product produced by the method of claim 11.

17. A process for producing a functionalized saturated thermoplastic elastomer comprising:

(a) copolymerizing, under polymerization conditions to form a thermoplastic elastomer

(i) a monomer system selected from (a) at least one C₄ to C₃₀ α

-olefin and (b) ethylene with 20 to 40 mole percent of a higher α

-olefin, and

(ii) a comonomer of the general formula

wherein R′

is the remnant of an initiator, R″

is a polymerized monoalkenyl arene unit, R is alkyl, n is an integer of from 0 to 16, and x is an integer sufficient to give said monomer a molecular weight within the range of 500-30,000; and

(b) contacting said thermoplastic elastomer with a free radical initiator and a functionalizing monomer having at least one point of unsaturation.

18. A method according to claim 17 wherein said functionalizing monomer is selected from carboxylic acids and derivatives of carboxylic acids.

19. A method according to claim 17 wherein R′

is is the remnant of an unsaturated initiator, said comonomer thus being an α

,ω

-olefin.

20. A method according to claim 17 wherein

(a) said comonomer is formed by reacting an alkyl alkali metal initiator with a monoalkenyl aromatic compound to give a living aromatic polymer chain said reacting being done in an α

-olefin solvent selected from C₆ to C₃₀ olefins;

(b) thereafter reacting said living aromatic polymer chain with an alkenyl halosilane in the presence of a solvent which is an α

-olefin selected from C₄ to C₃₀ α

-olefin; and

(c) thereafter reacting said comonomer with a monomer which is an α

-olefin selected from C₄ to C₃₀ α

-olefins to give a saturated thermoplastic elastomer, no other solvent being used in said method.

21. A method according to claim 20 wherein said α

-olefin of (A), (B), and (C) is the same α

-olefin.

22. A method according to claim 17 wherein said monomer system is a single monomer selected from octene and decene, said comonomer is the reaction product of a living polystyrene lithium chain and 6-hex-1-enyl dimethylchlorsilane, said copolymerizing is done in the presence of a transition metal catalyst.

23. A composition produced by the method of claim 22.

24. A composition produced by the method of claim 17.

25. A process for producing a functionalized saturated thermoplastic elastomer which comprises:

(a) copolymerizing;

(i) a monomer system selected from at least one C₄ to C₃₀ α

-olefin and ethylene plus 20 to 40 mole percent of a higher α

-olefin with

(ii) a comonomer formed by terminating a living polystyrene-lithium chain having a vinyl group at an end of said chain opposite the thus terminated lithium to produce a thermoplastic elastomer; and

(b) contacting said thermoplastic elastomer with a functionalizing monomer having at least one point of unsaturation.

26. A process comprising:

metallating an EPDM polymer;

contacting the thus metallated EPDM polymer with at least one monoalkenyl aromatic compound under anionic polymerization conditions to form anionically polymerized monoalkenyl aromatic compound side chains, thus giving a thermoplastic elastomer; and

contacting said thermoplastic elastomer with a free radical initiator and a functionalizing monomer having at least one point of unsaturation.

27. A method according to claim 26 wherein said metallating is done with secondary butyllithium, said monoalkenyl aromatic compound is styrene, said free radical initiator is a peroxide and said functionalizing monomer is a maleic anhydride.

28. A product produced by the method of claim 27.

29. A product produced by the method of claim 26.