Hydrosilane additives for increased polyolefin molecular weight
A process for polymerizing olefins is disclosed. The process uses a hydrosilane in a polymerization catalyzed by an open architecture, bridged indenoindolyl organometallic complex and an activator. Polyolefins from the process have increased molecular weight.
1. A process which comprises polymerizing an olefin in the presence of a hydrosilane and a catalyst system which comprises an activator and a bridged indenoindolyl Group 4-6 transition metal complex having open archit architure, wherein the hydrosilane is used in an amount effective to increase polyolefin molecular weight.
2. The process of claim 1 wherein the transition metal complex has the general structure selected from the group consisting of:
in which M is a Group 4-6 transition metal, G is a linking group, R is alkyl, aryl, dialkylboryl, or trialkylsilyl, R 1 is C 1 -C 20 hydrocarbyl, X is alkyl, aryl, alkoxy, aryloxy, halide, dlalkylamino, or slioxy, and n satisfies the valence of M.
3. The process of claim 1 wherein the olelin is selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and mixtures thereof.
4. The process of claim 1 wherein the activator is selected from the group consisting of alumoxanes, ionic borates, ionic aluminates, alkylaluminums, and aluminoboronates.
5. The process of claim 2 wherein M is a Group 4 transition metal.
6. The process of claim 2 wherein M is Ti or Zr, G is dimethylsilyl, and X is halide or alkyl.
7. The process of claim 1 wherein the polymerization is performed at a temperature within the range of about 30° C. to about 100° C.
8. A slurry polymerization process of claim 1 .
9. A gas-phase polymerization process of claim 1 .
10. The process of claim 1 wherein the hydrosilane has the general structure:
wherein each R 2 is independently selected from the group consisting of hydrogen, C 1 -C 10 hydrocarbyl, and trifluoroalkyl; R 3 is C 1 -C 10 hydrocarbyl; x is an integer from 0 to 200 and R 4 a selected from the group consisting of hydrogen, trialkylsiloxy and C 1 -C 10 hydrocarbyl with the proviso that when x is 0, R 4 is hydrogen.
11. The process of claim 10 wherein R 2 is C 1 -C 10 hydrocarbyl, x is 0 and R 4 is hydrogen.
12. The process of claim 10 wherein x is an integer from 5 to 100, R 2 is C 1 -C 10 hydrocarkyl, and R 4 is trialkylsiloxy.
13. The process of claim 12 wherein R 2 and R 3 are methyl and R 4 is trimethylsiloxy.
14. The process of claim 10 wherein the hydrosilane is used at a level of from about 20 to about 1000 grams of silicon per gram of transition metal.
15. The process of clam 14 wherein the hydrosilane is used at a level of from about 50 to about 500 grams of silicon per gram of transition metal.