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. An ethylene polymer composition having:
a d50 average particle size in a range from 150 to 600 μm;
a particle size span in a range from 0.5 to 1.6;
less than or equal to 20 wt % of the ethylene polymer composition with a particle size of less than 100 μm; and
less than or equal to 5 wt % of the ethylene polymer composition with a particle size of greater than 1000 μm;
wherein the ethylene polymer composition contains less than 0.1 ppm by weight, independently, of Mg, V, Ti, and Cr.
2. The ethylene polymer composition of claim 1 , wherein the ethylene polymer composition has:
a d90 particle size from 300 to 800 μm;
a ratio of d90/d10 from 2 to 5;
a change of less than 7% in a mean size of samples taken from a top to a bottom of a settled polymer bed in a segregation test in accordance with ASTM 6941;
a range of density across the ethylene polymer composition of less than 0.02 g/cm 3 ;
a HLMI from 4 to 10 g/10 min; and
a density from 0.944 to 0.955 g/cm 3 .
3. The ethylene polymer composition of claim 1 , wherein the d50 average particle size is in a range from 150 to 450 μm.
4. The ethylene polymer composition of claim 1 , wherein the particle size span is in a range from 1.1 to 1.5.
5. The composition of claim 1 , wherein less than or equal to 5 wt % of the ethylene polymer composition has a particle size of less than 100 μm.
6. The composition of claim 1 , wherein less than or equal to 2 wt % of the ethylene polymer composition has a particle size of greater than 1000 μm.
7. The ethylene polymer composition of claim 1 , wherein the ethylene polymer composition has a d90 particle size from 400 to 750 μm.
8. The ethylene polymer composition of claim 1 , wherein the ethylene polymer composition has a ratio of d90/d10 from 2 to 4.
9. The ethylene polymer composition of claim 1 , wherein the ethylene polymer composition comprises an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, and/or an ethylene/1-octene copolymer.
10. The ethylene polymer composition of claim 1 , wherein:
less than or equal to 10 wt % of the ethylene polymer composition has a particle size of less than 100 μm;
less than or equal to 3 wt % of the ethylene polymer composition has a particle size of greater than 1000 μm; and
the ethylene polymer composition comprises an ethylene/α-olefin copolymer.
11. The ethylene polymer composition of claim 10 , wherein the ethylene polymer composition is characterized by a film gel count of less than 50 gels per ft 2 of 25 micron film, wherein gels are film defects with a size greater than 200 microns.
12. The ethylene polymer composition of claim 10 , wherein:
the d50 average particle size is in a range from 200 to 275 μm; and
the particle size span is in a range from 1.1 to 1.5.
13. The ethylene polymer composition of claim 10 , wherein the ethylene polymer composition has a d90 particle size from 400 to 500 μm.
14. The ethylene polymer composition of claim 10 , wherein the ethylene polymer composition has a change of less than 5% in a mean size of samples taken from a top to a bottom of a settled polymer bed in a segregation test in accordance with ASTM 6941.
15. The ethylene polymer composition of claim 10 , wherein the ethylene polymer composition has a range of density across the ethylene polymer composition of less than 0.01 g/cm 3 .
16. An ethylene polymer composition having:
a d50 average particle size in a range from 150 to 600 μm;
a particle size span in a range from 0.5 to 1.6;
less than or equal to 20 wt % of the ethylene polymer composition with a particle size of less than 100 μm; and
less than or equal to 5 wt % of the ethylene polymer composition with a particle size of greater than 1000 μm;
wherein the ethylene polymer composition has a change of less than 10% in a mean size of samples taken from a top to a bottom of a settled polymer bed in a segregation test in accordance with ASTM 6941.
17. The ethylene polymer composition of claim 16 , wherein the ethylene polymer composition:
has a d90 particle size from 400 to 750 μm;
a ratio of d90/d10 from 2 to 5; and
comprises an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, and/or an ethylene/1-octene copolymer.
18. The ethylene polymer composition of claim 17 , wherein:
the d50 average particle size is in a range from 200 to 400 μm;
the particle size span is in a range from 1.1 to 1.5;
less than or equal to 5 wt % of the ethylene polymer composition has a particle size of less than 100 μm; and
less than or equal to 1 wt % of the ethylene polymer composition has a particle size of greater than 1000 μm.
19. The composition of claim 16 , wherein the ethylene polymer composition has a change of less than 5% in a mean size of samples taken from a top to a bottom of a settled polymer bed in a segregation test in accordance with ASTM 6941.
20. An ethylene polymer composition having:
a d50 average particle size in a range from 150 to 600 μm;
a particle size span in a range from 0.5 to 1.6;
less than or equal to 20 wt % of the ethylene polymer composition with a particle size of less than 100 μm; and
less than or equal to 5 wt % of the ethylene polymer composition with a particle size of greater than 1000 μm;
wherein the ethylene polymer composition has a range of density across the ethylene polymer composition of less than 0.03 g/cm 3 .
21. The ethylene polymer composition of claim 20 , wherein:
the d50 average particle size is in a range from 200 to 400 μm;
the particle size span is in a range from 1 to 1.6;
less than or equal to 5 wt % of the ethylene polymer composition has a particle size of less than 100 μm;
A less than or equal to 2 wt % of the ethylene polymer composition has a particle size of greater than 1000 μm; and
the ethylene polymer composition comprises an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, and/or an ethylene/1-octene copolymer.
22. The ethylene polymer composition of claim 21 , wherein the ethylene polymer composition has a range of density across the ethylene polymer composition of less than 0.01 g/cm 3 .
23. An ethylene polymer composition having:
a HLMI from 4 to 10 g/10 min;
a density from 0.944 to 0.955 g/cm 3 ;
a d50 average particle size in a range from 150 to 600 μm;
a particle size span in a range from 0.5 to 1.6;
less than or equal to 20 wt % of the ethylene polymer composition with a particle size of less than 100 μm; and
less than or equal to 5 wt % of the ethylene polymer composition with a particle size of greater than 1000 μm.
24. The ethylene polymer composition of claim 23 , wherein:
the d50 average particle size is in a range from 175 to 275 μm;
the particle size span is in a range from 1.1 to 1.5;
less than or equal to 5 wt % of the ethylene polymer composition has a particle size of less than 100 μm; and
less than or equal to 1 wt % of the ethylene polymer composition has a particle size of greater than 1000 μm.
25. The ethylene polymer composition of claim 24 , wherein the ethylene polymer composition:
has a d90 particle size from 400 to 500 μm;
a ratio of d90/d10 from 2.4 to 3.6; and
comprises an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, and/or an ethylene/1-octene copolymer.
26. An ethylene polymer composition having:
a d50 average particle size in a range from 150 to 600 μm;
a particle size span in a range from 0.5 to 1.6;
less than or equal to 20 wt % of the ethylene polymer composition with a particle size of less than 100 μm; and
less than or equal to 5 wt % of the ethylene polymer composition with a particle size of greater than 1000 μm;
wherein the ethylene polymer composition is characterized by a film gel count of less than 50 gels per ft 2 of 25 micron film, wherein gels are film defects with a size greater than 200 microns.
27. The ethylene polymer composition of claim 26 , wherein the composition has:
a d90 particle size from 400 to 750 μm; and
a ratio of d90/d10 from 2 to 5.
28. The ethylene polymer composition of claim 26 , wherein:
the d50 average particle size is in a range from 200 to 400 μm;
the particle size span is in a range from 1.1 to 1.5;
less than or equal to 5 wt % of the ethylene polymer composition has a particle size of less than 100 μm;
less than or equal to 1 wt % of the ethylene polymer composition has a particle size of greater than 1000 μm; and
the ethylene polymer composition comprises an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, and/or an ethylene/1-octene copolymer.
29. The ethylene polymer composition of claim 26 , wherein the film gel count is less than 10 gels per ft 2 of 25 micron film.