Claims
- 1. A polymerization process comprising contacting under slurry polymerization conditions at a temperature within a range of about 200° F. to about 226° F. (about 93° C. to about 108° C.) in an isobutane diluent:
a) ethylene monomer; b) at least 1 mono-1-olefin comonomer having about three to eight carbon atoms per molecule; c) a catalyst system comprising chromium supported on a silica-titania support, wherein said support comprises from about 1 to about 10 weight percent titanium, based on the weight on the support, wherein said catalyst system has a pore volume within a range of about 0.5 to about 1.3 ml/g, a surface area within a range about 150 to 400 m2/g, and said catalyst system has been activated at a temperature within a range of about 800° F. to about 1300° F. (about 427° C. to about 704° C.); d) about 1 to about 6 mg/kg, based on total reactor contents, of a trialkylboron compound; and e) recovering an ethylene/mono-1-olefin copolymer.
- 2. A process according to claim 1 wherein said comonomer is selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and mixtures thereof.
- 3. A process according to claim 2 wherein said comonomer is 1-hexene.
- 4. A process according to claim 1 wherein said reactor temperature is within a range of about 210° F. to 220° F.
- 5. A process according to claim 1 wherein said titania of the silica-titania support is coprecipitated with the silica.
- 6. A process according to claim 1 wherein said catalyst system is aged twice and wherein the first aging is at a substantially neutral pH and wherein the second aging is at an alkaline pH.
- 7. A process according to claim 1 wherein said catalyst system is calcined at a temperature within a range of about 800° F. to about 1300° F.
- 8. A process according to claim 1 wherein trialkyboron cocatalyst is present in the reactor in an amount within a range of 2 to about 4 mg/kg.
- 9. A composition comprising ethylene and a mono-1-olefin having from about 3 to about 8 carbon atoms carbon atoms per molecule, wherein said copolymer has a high load melt index (HMLI) within a range of about 10 to about 80 g/10 minutes, a density within a range of about 0.95 to 0.96 g/cc, a shear response (HLMI/MI) is within a range of about 100 to about 250, a weight swell lower than about 380%, and a die swell lower than about 43%, an ESCR of greater than about 200 hours, a Mw/Mn of greater than about 12 and the onset of melt fracture of greater than about 2000 sec−1.
- 10. A composition according to claim 9 wherein said mono-1-olefin is 1-hexene.
- 11. A composition according to claim 9 wherein said high-load melt index is within a range of 13 to 40 grams/10 minutes.
- 12. A composition according to claim 9 wherein said shear response (HLMI/MI) is within a range of 125 to 175.
- 13. A polymerization process comprising contacting under slurry polymerization conditions at a temperature within a range of about 210° F. to about 220° F. in an isobutane diluent:
a) ethylene monomer; b) 1-hexene comonomer; c) a catalyst system comprising chromium supported on a silica-titania support, where in said support comprises from 2 to 8 weight percent titanium, based on the weight on the support, wherein said catalyst system has a pore volume within a range of 0.8 to 1.2 ml/g, a surface area within a range of 250 to 350 m2/g, and said catalyst system has been activated at a temperature within a range of 1 100° F. to 1200° F.; d) about 2 to about 4 mg/kg, based on total reactor contents, of a triethylboron cocatalyst; and e) recovering an ethylene/1-hexene copolymer.
- 14. A copolymer composition comprising ethylene and 1-hexene, wherein said copolymer has a high load melt index (HMLI) within a range of 15 10 to 30 g 10 minutes, a density within a range of 0.954 to 0.956 g/cc, a shear response (HLMI/MI) is within a range of 125 to 175, a weight swell lower than about 330%, and a die swell lower than about 38% an ESCR, condition A, of greater than about 1000 hours, a Mw/Mn of within a range of 15 to 22. and the onset of melt fracture of greater than about 2300 sec−1.
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 09/773,296, filed Jan. 31, 2001, which is a division of U.S. patent application Ser. No. 09/213,884, filed Dec. 17, 1998, now U.S. Pat. No. 6,204,346. U.S. patent application Ser. Nos. 09/773,296 filed Jan. 31, 2001 and 09/213,884 filed Dec. 17, 1998 are expressly incorporated by referenced in their entirety.
Divisions (1)
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Number |
Date |
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Parent |
09213884 |
Dec 1998 |
US |
Child |
09773296 |
Jan 2001 |
US |
Continuations (1)
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09773296 |
Jan 2001 |
US |
Child |
10683448 |
Oct 2003 |
US |