Polyolefin production with a high performance support for a metallocene catalyst system

Abstract

The invention is directed to a metallocene catalyst system and a process for preparing the system. The metallocene catalyst system comprises a support and metallocene bound substantially throughout the support. The selection of certain supports facilitates the production of metallocene catalyst systems having increased catalytic activity than previously recognized.

1 . A metallocene catalyst system (MCS) comprising: 
 a support; and    a metallocene bound substantially throughout said support, wherein on exposure to a reaction environment comprising about 300 g to about 400 g propylene per Liter of reactor volume, about 23 ppm by weight of said MCS, about 37 ppm by weight H 2 , and about 46 ppm triethylaluminum in a 4 liter reactor at about 67° C. and about one hour reaction time, said MCS has a catalytic activity of at least about 10,400 g of polypropylene/g of MCS/hr.    
   
   
       2 . The MCS as recited in  claim 1  wherein said metallocene comprises rac dimethylsilanediyl bis(2-methyl-4-phenyl indenyl)zirconium dichloride and said propylene comprises polymer grade propylene further purified to having COS levels of less than about 20 ppb, O 2  levels of less than about 5 ppm and H 2 O levels of less than about 5 ppm.  
   
   
       3 . The MCS as recited in  claim 1  wherein said catalytic activity is obtained for a metallocene loading up to about 1 wt %.  
   
   
       4 . The MCS as recited in  claim 3  wherein said catalytic activity is at least about 11,800 g of said polypropylene/g of said MCS/hr.  
   
   
       5 . The MCS as recited in  claim 1  wherein said catalytic activity is at least about 14,040 g of said polypropylene/g of said MCS/hr.  
   
   
       6 . The MCS as recited in  claim 5  wherein said catalytic activity is obtained for a metallocene loading of up to about 2 wt %.  
   
   
       7 . The MCS as recited in  claim 1  wherein said catalytic activity obtained for a metallocene loading of about 2 wt % is at least about 20 percent higher than said catalytic activity obtained for a metallocene loading of about 1 wt %.  
   
   
       8 . A metallocene catalyst system (MCS) comprising: 
 a catalyst support system including a support having an average pore diameter of greater than about 140 Angstroms; and    a metallocene bound substantially throughout said support, said MCS having a catalytic activity for a metallocene loading of about 2 wt % that is at least about 20 percent higher than said catalytic activity for said metallocene loading of about 1 wt    
   
   
       9 . The MCS as recited in  claim 8  wherein said average pore diameter is between about 150 Angstroms and about 450 Angstroms.  
   
   
       10 . The MCS as recited in  claim 8  wherein said metallocene is one or more of an isospecific stereo rigid metallocene characterized by the formula:  
       R 2  bis(C 5 (R 1 ) n )MeQp  wherein each (C 5 (R 1 ) n ) is a substituted cyclopentadienyl ring; n may range from 1 to 20 so long as the number of sites available for substitution are not exceeded; each R 1  is the same or different and is a hydrogen or hydrocarbyl radical having 1-20 carbon atoms; R 2  is a structural bridge between said two (C 5 (R 1 ) n ) rings imparting stereorigidity to said metallocene, Me, and imparting a chiral environment to a metal, Me, and R 2  is selected from the group consisting of an alkylene radical having 1-4 carbon atoms, a silicon hydrocarbyl radical, a germanium hydrocarbyl radical, a phosphorus hydrocarbyl radical, a nitrogen hydrocarbyl radical, a boron hydrocarbyl radical, and an aluminum hydrocarbyl radical; said Me is a group 4, 5, or 6 metal as designated in the Periodic Table of Elements; each Q may be independently selected from a hydrocarbyl radical having 1-20 carbon atoms or is a halogen; and 0≦p≦3.    
   
   
       11 . The MCS as recited in  claim 8  wherein said metallocene is selected from the group consisting of: 
 rac dimethylsilanediyl bis(2-methyl-4-phenyl indenyl)zirconium dichloride;    rac dimethylsilanediyl bis(2-methyl indenyl)zirconium dichloride,    rac dimethylsilanediyl bis(2-methyl-4,5-benzoindenyl)zirconium dichloride; and    rac dimethylsilanediyl bis(2-methyl-4-(1-naphthyl) indenyl) zirconium dichloride.    
   
   
       12 . The MCS as recited in  claim 8  wherein said MCS catalyzes the polymerization of a propylene comprising polymer grade propylene further purified to having COS levels of less than about 20 ppb, O 2  levels of less than about 5 ppm and H 2 O levels of less than about 5 ppm.  
   
   
       13 . A process for the preparation of a metallocene catalyst system (MCS) comprising: 
 providing a support having a surface defining pores; and    attaching a metallocene substantially throughout said support to form a MCS having a catalytic activity for a metallocene loading of about 2 wt % that is at least about 20 percent higher than said catalytic activity for said metallocene loading of about 1 wt %.    
   
   
       14 . The process as recited in  claim 13  further including said support comprising silica, attaching an activator to said silica support substantially throughout said pore volume and attaching said metallocene to said activator to form said MCS.  
   
   
       15 . The process as recited in  claim 13  wherein said support is substantially spheroidal and said pores have a peak pore volume of greater than about 0.115 mL/g at a pore diameter between about 250 Angstroms and about 350 Angstroms.  
   
   
       16 . The process as recited in  claim 13  wherein said support is substantially spheroidal and said pores provide a peak surface area of at least about 14.3 m 2 /g at a pore diameter between about 250 Angstroms and about 330 Angstroms.  
   
   
       17 . A process for the polymerization of polyolefin comprising: 
 preparing a metallocene catalyst system (MCS) having a catalytic activity for a metallocene loading of about 2 wt % that is at least about 20 percent higher than said catalytic activity for said metallocene loading of about 1 wt %;    introducing said MCS into a polymerization reaction chamber; and    contacting at least one olefin monomer with said MCS in said reaction chamber.    
   
   
       18 . The process as recited in  claim 17  wherein said olefin monomer comprises an alpha olefin comprising ethylenically unsaturated hydrocarbons having between 2 and 20 Carbon atoms.  
   
   
       19 . The process as recited in  claim 17  wherein said olefin monomer is selected from the group consisting of: 
 a mixture of propylene and ethylene;    a mixture of propylene, butene and ethylene; and    a mixture of propylene and butene.    
   
   
       20 . The process as recited in  claim 17  wherein said olefin monomer comprises polymer grade propylene further purified to having COS levels of less than about 20 ppb, O 2  levels of less than about 5 ppm and H 2 O levels of less than about 5 ppm.  
   
   
       21 . A polyolefin produced by the process comprising: 
 introducing a metallocene catalyst system (MCS) into a polymerization reaction chamber said MCS having a catalytic activity for a metallocene loading of about 2 wt % that is at least about 20 percent higher than said catalytic activity for said metallocene loading of about 1 wt %; and    contacting at least one olefin monomer with said MCS in said reaction chamber.    
   
   
       22 . The polyolefin as recited in  claim 21  wherein said polyolefin has an average particle diameter between about 400 and about 2000 microns.  
   
   
       23 . The polyolefin as recited in  claim 21  wherein said polyolefin has an average particle diameter between about 600 and about 1500 microns.  
   
   
       24 . The polyolefin as recited in  claim 21  wherein said polyolefin has a bulk density of at least about 0.37 g/cc.  
   
   
       25 . The polyolefin as recited in  claim 21  wherein said polyolefin is converted into a resin used for the manufacture of films, fibers or injection molded articles.  
   
   
       26 . The process as recited in  claim 21  wherein said olefin monomer comprises polymer grade propylene further purified to having COS levels of less than about 20 ppb, O 2  levels of less than about 5 ppm and H 2 O levels of less than about 5 ppm.