Conjugated diene polymers and copolymer blocks having high vinyl content prepared using mixed microstructure control agents and process for preparing same
View Patent ↗Disclosed is a process for preparing polymers and copolymer blocks of conjugated dienes with high amounts of branching, commonly referred to as vinyl content, comprising the use of at least two microstructure control agents. One of the microstructure control agents can be a bulk microstructure control agents such as diethyl ether. The other microstructure control agent is a specific microstructure control agent such as 1,2-diethoxypropane. The use of a bulk and a specific microstructure control agent together can allow for the production of high levels of vinyl content at high polymerization rates without the undesirable affects experienced with either one alone.
1. A process for preparing a conjugated diene polymer or copolymer block comprising combining: (a) an anionic polymerization site; (b) a conjugated diene monomer; and (c) at least two microstructure control agents; under reaction conditions sufficient to form a living polymer admixture wherein at least one of the at least two microstructure control agents is a monooxygenated acyclic ether and at least one of the at least two microstructure control agents is a polyoxygenated ether effective in forming chelated complexes with Li + and wherein the at least two microstructure control agents are added simultaneously.
2. The process of claim 1 wherein the monooxygenated ether is selected from diethyl ether, dimethyl ether, dibutyl ether, methyl ethyl ether and mixtures thereof.
3. The process of claim 3 wherein the monooxygenated ether is diethyl ether.
4. The process of claim 1 wherein the polyoxygenated ether effective in forming chelated complexes with Li + is selected from 1,2-diethoxyethane, 1,2-diethoxypropane, o-dimethoxybenzene, 1-t-butoxy-2-n-butoxyethane, n-C 4 H 9 OCH 2 CH 2 O-n-C 4 H 9 , crown ethers having more than one oxygen atom in close proximity and mixtures thereof.
5. The process of claim 1 wherein the conjugated diene monomer is selected from the group, 1,3-butadiene, isoprene, piperylene, methylpentadiene, 1,3-cyclohexadiene, 1,3-cyclohepatdiene, 1,3-cyclooctadiene phenylbutadiene, 3,4-dimethyl-1,3-hexadiene, 4,5-diethyl-1,3-octadiene, and mixtures thereof.
6. The process of claim 5 wherein the conjugated diene monomer is 1,3-butadiene.
7. The process of claim 1 wherein the monooxygenated acyclic ether is present in a concentration from about 0.1 to about 10 weight percent and the polyoxygenated ether effective in forming chelated complexes with Li + is present in a concentration from about 1 to about 1000 parts per million.
8. The process of claim 1 wherein the process is for preparing a conjugated diene copolymer and the anionic polymerization site is a living polymer.
9. The process of claim 8 additionally comprising a step of preparing the anionic polymerization site by admixing a monomer different from the conjugated diene monomer with an initiator.
10. The process of claim 9 wherein the monomer different from the conjugated diene monomer is styrene.
11. The process of claim 10 wherein the polyoxygenated ether effective in forming chelated complexes with Li+ is 1,2-diethoxypropane.
12. The process of claim 11 further comprising using a coupling agent to form a coupled block copolymer.
13. The polymer or block copolymer of claim 1 wherein the polymer or block copolymer is a copolymer.
14. The copolymer of claim 13 wherein the copolymer has a general formula AB wherein B is a copolymer block prepared using a conjugated diene and A is a block prepared using a different monomer.
15. The copolymer of claim 14 wherein A is styrene.
16. The copolymer of claim 15 additionally comprising a second A block resulting in a general structure of ABA.
17. The copolymer of claim 13 wherein the copolymer is a copolymer having a general formula (AB) n X wherein A is a vinyl aromatic copolymer block; B is a conjugated diene copolymer block; X is the residue of a coupling agent; and n is from 2 to 40.
18. The copolymer of claim 13 wherein the copolymer is a copolymer having a general formula (ABA) n X wherein A is a vinyl aromatic copolymer block; B is a conjugated diene copolymer block; X is the residue of a coupling agent; and n is from 2 to 40.
19. The copolymer of claim 13 wherein the copolymer is a copolymer having a general formula (BAB) n X wherein A is a vinyl aromatic copolymer block; B is a conjugated diene copolymer block; X is the residue of a coupling agent; and n is from 2 to 40.
20. The process of claim 1 wherein the monooxygenated ether is diethyl ether and the polyoxygenated ether effective in forming chelated complexes with Li + is 1,2-diethoxypropane.
21. The process of claim 4 wherein the polyoxygenated ether effective in forming chelated complexes with Li + is o-dimethoxybenzene.
22. The process of claim 4 wherein the polyoxygenated ether effective in forming chelated complexes with Li + is 1,2-diethoxypropane.