Particle size control of metallocene catalyst systems in loop slurry polymerization reactors
Catalyst compositions containing a metallocene compound, a solid activator, and a co-catalyst, in which the solid activator or the supported metallocene catalyst has a d50 average particle size of 15 to 50 μm and a particle size distribution of 0.5 to 1.5, can be contacted with an olefin in a loop slurry reactor to produce an olefin polymer. A representative ethylene-based polymer produced using the catalyst composition has excellent dart impact strength and low gels, and can be characterized by a HLMI from 4 to 10 g/10 min, a density from 0.944 to 0.955 g/cm 3 , a higher molecular weight component with a Mn from 280,000 to 440,000 g/mol, and a lower molecular weight component with a Mw from 30,000 to 45,000 g/mol and a ratio of Mz/Mw ranging from 2.3 to 3.4.
1. A catalyst composition comprising:
a metallocene compound;
a solid activator;
and optionally, a co-catalyst;
wherein the solid activator has:
a d50 average particle size in a range from 15 to 30 μm; and
a particle size span in a range from 0.6 to 1.3; and
wherein an amount of the solid activator having:
a particle size of less than 10 μm is less than or equal to 8 wt %; and
a particle size of greater than 45 μm is less than or equal to 10 wt %.
2. The catalyst composition of claim 1 , wherein:
the solid activator comprises fluorided alumina, sulfated alumina, fluorided silica-alumina, sulfated silica-alumina, fluorided silica-coated alumina, fluorided-chlorided silica-coated alumina, sulfated silica-coated alumina, or any combination thereof; and
the catalyst composition comprises an organoaluminum co-catalyst.
3. The catalyst composition of claim 1 , wherein the catalyst composition:
is substantially free of aluminoxane compounds, organoboron or organoborate compounds, ionizing ionic compounds, or combinations thereof; and
comprises a single metallocene compound or two metallocene compounds at a weight ratio in a range from 10:1 to 1:10.
4. A polymerization process comprising:
contacting the catalyst composition of claim 1 with an olefin monomer and an optional olefin comonomer in a polymerization reactor system comprising a loop slurry reactor under polymerization conditions to produce an olefin polymer.
5. The polymerization process of claim 4 , wherein:
the catalyst composition is contacted with ethylene and an olefin comonomer comprising 1-butene, 1-hexene, 1-octene, or a mixture thereof; and
the solid activator comprises a fluorided solid oxide and/or a sulfated solid oxide.
6. The polymerization process of claim 5 , wherein the polymerization reactor system comprises only one loop slurry reactor or the loop slurry reactor and one additional reactor.
7. The catalyst composition of claim 1 , wherein the amount of the solid activator having a particle size of greater than 45 μm is less than or equal to 5 wt %.
8. The catalyst composition of claim 7 , wherein the d50 average particle size is from 15 to 25 μm.
9. The catalyst composition of claim 7 , wherein the d50 average particle size is from 17 to 25 μm.
10. The catalyst composition of claim 7 , wherein the span is from 0.7 to 1.2.
11. The catalyst composition of claim 7 , wherein the span is from 0.6 to 1.1.
12. The catalyst composition of claim 11 , wherein the d50 average particle size is from 17 to 27 μm.
13. The catalyst composition of claim 11 , wherein the d50 average particle size is from 20 to 30 μm.
14. The catalyst composition of claim 1 , wherein the amount of the solid activator having a particle size of less than 10 μm is less than or equal to 5 wt. %.
15. The catalyst composition of claim 14 , wherein the d50 average particle size is from 15 to 25 μm.
16. The catalyst composition of claim 14 , wherein the d50 average particle size is from 17 to 25 μm.
17. The catalyst composition of claim 14 , wherein the span is from 0.7 to 1.2.
18. The catalyst composition of claim 14 , wherein the span is from 0.6 to 1.1.
19. The catalyst composition of claim 18 , wherein the d50 average particle size is from 17 to 27 μm.
20. The catalyst composition of claim 18 , wherein the d50 average particle size is from 20 to 30 μm.
21. The catalyst composition of claim 1 , wherein the amount of the solid activator having:
a particle size of less than 10 μm is less than or equal to 5 wt %; and
a particle size of greater than 45 μm is less than or equal to 5 wt %.
22. The catalyst composition of claim 1 , wherein the amount of the solid activator having:
a particle size of less than 10 μm is less than or equal to 2 wt %; and
a particle size of greater than 45 μm is less than or equal to 2 wt %.
23. The catalyst composition of claim 22 , wherein the d50 average particle size is from 17 to 25 μm.
24. The catalyst composition of claim 1 , wherein:
the d50 average particle size is from 15 to 25 μm; and
the particle size span is from 0.6 to 1.1.
25. The catalyst composition of claim 1 , wherein:
the d50 average particle size is from 17 to 27 μm; and
the particle size span is from 0.7 to 1.2.
26. A catalyst composition comprising:
a supported metallocene catalyst and an optional co-catalyst;
wherein the supported metallocene catalyst has:
a d50 average particle size in a range from 17 to 27 μm; and
a particle size span in a range from 0.6 to 1.3; and
wherein an amount of the supported metallocene catalyst having:
a particle size of less than 10 μm is less than or equal to 5 wt %; and
a particle size of greater than 45 μm is less than or equal to 5 wt %.
27. The catalyst composition of claim 26 , wherein:
the d50 particle size is from 17 to 25 μm; and
the span is from 0.6 to 1.1.
28. The catalyst composition of claim 26 , wherein:
the d50 particle size is from 17 to 25 μm; and
the span is from 0.7 to 1.2.
29. The catalyst composition of claim 26 , wherein the amount of the supported metallocene catalyst having:
a particle size of less than 10 μm is less than or equal to 2 wt %; and
a particle size of greater than 45 μm is less than or equal to 2 wt %.
30. The catalyst composition of claim 26 , wherein the supported metallocene catalyst has a ratio of d90/d10 from 1.8 to 3.
31. The catalyst composition of claim 26 , wherein the supported metallocene catalyst comprises a single metallocene compound.
32. The catalyst composition of claim 26 , wherein the supported metallocene catalyst comprises two metallocene compounds.
33. A polymerization process comprising:
contacting the catalyst composition of claim 26 with an olefin monomer and an optional olefin comonomer in a polymerization reactor system comprising a loop slurry reactor under polymerization conditions to produce an olefin polymer.
34. The process of claim 33 , wherein the catalyst composition is contacted with ethylene and an olefin comonomer comprising 1-butene, 1-hexene, 1-octene, or a mixture thereof.