Process for the polymerization of alpha olefins and non-conjugated dienes using a toluene free homogenous co-catalyst system with metallocene pro-catalysts
A homogenous toluene free catalyst system for producing a polyolefin elastomer possessing a unique combination of properties employing a particular type of a metallocene catalyst. The homogenous toluene free catalyst system having a co-catalyst for activating the metallocene pro-catalyst employing a specific molar ratio of the components of the co-catalyst blend to the metal of the pro-catalyst.
1. A process for the polymerization or copolymerization of at least one alpha olefin, and optionally at least one diene monomer, to obtain an elastomer, the process consisting of:
a. forming a catalytically effective homogenous solution of toluene free aliphatic hydrocarbon catalyst mixture by blending together:
(i) a co-catalyst blend consisting of:
(a) a modified methylaluminoxane (MMAO), alkylaluminum alkoxide, siloxalane, dimeric aluminoxane, or oligomeric aluminoxane in an aliphatic hydrocarbon; and
(b) a boron component having the formula M-R 3 , wherein the M is a boron, and R is an alkyl group, aryl group or combinations thereof, with each alkyl or aryl group possessing at least one electron-withdrawing substituent; and
(ii) a metallocene pro-catalyst comprising a transition metal; and
b. polymerizing the at least one alpha olefin in the presence of the catalytically effective homogenous solution of toluene free aliphatic hydrocarbon catalyst to form a polyolefin elastomer.
2. The process of claim 1 , wherein the boron component is a perfluoroarylborane.
3. The process of claim 2 , wherein the perfluoroarylborane is tris(penta fluorophenyl) borane.
4. The process of claim 1 , wherein the metallocene pro-catalyst is selected from the group consisting of: zirconocene dichloride, dimethylbis(indenyl) zirconium, racemic-ethylenebis(indenyl) zirconium dichloride, dimethylsilyl bis(cyclopentadienyl) zirconium dichloride, dimethylsilyl(tetramethylcyclopentadienyl)(tert-butylamido) titanium dichloride, diphenylmethylene (cyclopentadienyl-9-fluorenyl)zirconium dichloride and diphenylsilyl(cyclopentadienyl-9-fluorenyl)zirconium dichloride.
5. The process of claim 1 , wherein the alkylaluminum alkoxide is diisobutylaluminum-tert-butoxide.
6. The process of claim 1 , wherein the siloxalane is diethylaluminum trimethylsiloxane.
7. The process of claim 1 , wherein the dimeric aluminoxane is tetraisobutylaluminoxane.
8. The process of claim 1 , wherein the oligomeric aluminoxane is methylaluminoxane or modified methylaluminoxane.
9. The process of claim 1 , wherein a molar ratio of the first component of the co-catalyst blend to the transition metal is from 10 to 1,000.
10. The process of claim 1 , wherein the molar ratio of the second component of the co-catalyst blend to the transition metal is from 0.2 to 10.
11. The process of claim 1 , wherein the first component of the co-catalyst blend is combined with the second component of the co-catalyst.
12. The process of claim 11 , wherein the metallocene pro-catalyst is combined with a reaction product of the combination of the first component of the co-catalyst and the second component of the co-catalyst blend.
13. The process of claim 1 , wherein the co-catalyst blend further comprises a third component.
14. The process of claim 13 , wherein the third component is a trialkylaluminum.
15. The process of claim 14 , wherein the trialkylaluminum is selected from the group consisting of: trimethylaluminum, triethylaluminum, tri(n-propyl)aluminum, triisopropylaluminum, tri(n-butyl)aluminum, triisobutylaluminum tri(n-hexyl)aluminum and tri(n-octyl)aluminum.
16. The process of claim 13 , wherein the molar ratio of the third component of the co-catalyst blend to the transition metal is from 0.1 to 1,000.
17. The process of claim 1 , wherein the at least one alpha olefin contains from 2 carbon atoms to 20 carbon atoms and the diene, when present, is conjugated or nonconjugated, acyclic or cyclic, diene.
18. The process of claim 1 , wherein the at least one alpha olefin is selected from the group consisting of: ethylene and propylene.
19. The process of claim 1 , wherein the elastomer possesses an Mw from 70,000 to 2,000,000, an ML1+4 at 125 degrees Celsius from 10 to 200, an Mw/Mn from 1.5 to 10, and a Tg of below −25 degrees Celsius.
20. The process of claim 1 , wherein the elastomer possesses an Mw from 250,000 to 1,750,000, an ML1+4 at 125 degrees Celsius from 15 to 150, an Mw/Mn from 2 to 7.5, and a Tg of below −25 degrees Celsius.