Methods for Reducing Static Charge of a Catalyst and Methods for Using the Catalyst to Produce Polyolefins

Abstract

Catalysts and methods for making and using the same are provided. The method for fabricating a catalyst may includes contacting a supported catalyst with a monomer under conditions that reduce an overall charge of the catalyst to less than about 75% of an initial charge of the catalyst. A method for polymerization may include introducing a pre-polymerized catalyst and one or more olefins into a gas phase fluidized bed reactor, operating the reactor at conditions sufficient to produce a polyolefin, wherein the polymerization is carried out in the substantial absence of any continuity additives.

1 - 28 . (canceled) 
     
     
         29 . A method for gas phase olefin polymerization, comprising:
 injecting a pre-polymerized supported metallocene catalyst into a fluidized bed polymerization reactor system at the start-up of the reactor system, wherein the catalyst has a charge of less than about 0.3 μC/g;   contacting a monomer with the pre-polymerized metallocene catalyst; and   operating the reactor to produce a polyolefin, wherein no continuity additives are added to the reactor system during start-up and the polymerization is carried out in the substantial absence of any continuity additives for at least about 2 hours.   
     
     
         30 . The method of  claim 29 , further comprising, after start-up, discontinuing injection of the catalyst into the reactor system, and injecting a different catalyst into the reactor system. 
     
     
         31 . The method of  claim 29 , wherein said substantial absence means the concentration of continuity additives within the reactor is less than 5 ppmw, based on the rate of polyolefin production. 
     
     
         32 . The method of  claim 29 , wherein the polymerization is carried out in the substantial absence of any continuity additives for at least about 10 hours. 
     
     
         33 . The method of  claim 29 , wherein the polymerization is carried out in the substantial absence of any continuity additives for at least about 20 hours. 
     
     
         34 . The method of  claim 29 , wherein the polymerization is carried out in the substantial absence of any continuity additives for at least about 2 days. 
     
     
         35 . The method of  claim 29 , wherein no detectable amount of polymer agglomeration is formed during operation of the reactor. 
     
     
         36 . The method of  claim 29 , wherein the polymerization is carried out in the substantial absence of any continuity additives for at least about 10 hours and no detectable amount of polymer agglomeration is formed during operation of the reactor. 
     
     
         37 . The method of  claim 29 , wherein the polymerization is carried out in the substantial absence of any continuity additives for at least about 2 days and no detectable amount of polymer agglomeration is formed during operation of the reactor. 
     
     
         38 . The method of  claim 29 , wherein said monomer is ethylene. 
     
     
         39 . The method of  claim 29 , wherein the catalyst is also contacted with a comonomer comprising one or more C 3  to C 12  alpha-olefins. 
     
     
         40 . The method of  claim 39 , wherein said comonomer is hexene. 
     
     
         41 . The method of  claim 29 , wherein said pre-polymerized supported catalyst has coupled thereto the same polymer as the polymer created with the catalyst in said reactor system. 
     
     
         42 . The method of  claim 29 , wherein the catalyst further comprises a metallocene catalyst, a Ziegler-Natta catalyst, a Cr-based catalyst, a Ti-based catalyst, or a combination thereof. 
     
     
         43 . The method of  claim 29 , wherein the catalyst has the formula:
   Cp A Cp B MX n  or Cp A (A)Cp B MX n ,   
       wherein M is a Group 4, 5 or 6 atom; Cp A  and Cp B  are each bound to M and are independently selected from the group consisting of cyclopentadienyl ligands, substituted cyclopentadienyl ligands, ligands isolobal to cyclopentadienyl and substituted ligands isolobal to cyclopentadienyl; (A) is a divalent bridging group bound to both Cp A  and Cp B  selected from the group consisting of divalent C 1  to C 20  hydrocarbyls and C 1  to C 20  heteroatom containing hydrocarbonyls, wherein the heteroatom containing hydrocarbonyls comprise from one to three heteroatoms; X is a leaving group selected from the group consisting of chloride ions, bromide ions, C 1  to C 10  alkyls, and C 2  to C 12  alkenyls, carboxylates, acetylacetonates, and alkoxides; and n is an integer from 1 to 3. 
     
     
         44 . The catalyst of  claim 29 , wherein the catalyst comprises a polymer coupled to the catalyst, and wherein a ratio by weight of the primary monomer in the polymer to the catalyst is less than about 30:1. 
     
     
         45 . A method for fabricating the pre-polymerized supported metallocene catalyst of  claim 29 , the method comprising contacting a supported catalyst with a monomer under conditions that reduce the overall charge of the supported catalyst to less than about 75% of an initial charge of the catalyst. 
     
     
         46 . The method of  claim 45 , wherein the overall charge of the supported catalyst is reduced to less than about 50% of the initial charge of the catalyst. 
     
     
         47 . The method of  claim 45 , wherein the overall charge of the supported catalyst is reduced to less than about 30% of the initial charge of the catalyst.