Olefin polymerization catalyst compositions and method of preparation

Abstract

A method of making a solid procatalyst composition for use in a Ziegler-Natta olefin polymerization catalyst composition, said method comprising: contacting a precursor composition comprising a magnesium compound with a titanium halide compound and an internal electron donor in any order, in a suitable reaction medium to prepare a solid procatalyst composition, separating the solid procatalyst from the reaction medium, extracting the solid procatalyst composition by contacting the same one or more times with a liquid diluent at an elevated temperature for a period of time sufficient to prepare a solid procatalyst composition having a decreased titanium content compared to the titanium content of the solid procatalyst composition before said extraction, and recovering the solid procatalyst composition.

What is claimed is:  
     
         1 . A method of making a solid procatalyst composition for use in a Ziegler-Natta olefin polymerization procatalyst composition, said method comprising: 
 contacting a precursor composition comprising a magnesium compound with a titanium halide compound and an internal electron donor in any order, in a suitable reaction medium to prepare a solid procatalyst composition,    separating the solid procatalyst from the reaction medium,    extracting the solid procatalyst composition by contacting the same one or more times with a liquid diluent at an elevated temperature for a period of time sufficient to prepare a solid procatalyst composition having a decreased titanium content compared to the titanium content of the solid procatalyst composition before said extraction, and    recovering the solid procatalyst composition.    
     
     
         2 . The method of  claim 1  wherein the diluent is selected from the group consisting of toluene, xylene, isopentane, isooctane, chlorobenzene, and dichlorobenzene.  
     
     
         3 . The method of  claim 2  wherein the diluent is chlorobenzene.  
     
     
         4 . The method of  claim 1  wherein the extraction is conducted at a temperature above 45° C.  
     
     
         5 . The method of  claim 1  wherein the extraction is conducted at a temperature within the range of from about 115° C. to about 200° C.  
     
     
         6 . The method of  claim 5  wherein extraction takes place at a temperature within the range of from about 120° C. to about 150° C.  
     
     
         7 . The method of  claim 1  where the extraction is conducted for a period of time ranging from about 5 minutes to about 1 day.  
     
     
         8 . The method of  claim 1  wherein the extraction is repeated at least once.  
     
     
         9 . The method of  claim 1  wherein the solid procatalyst is contacted with a halide salt compound in a substitution reaction before or during the extraction step.  
     
     
         10 . The method of  claim 1  wherein the solid procatalyst is dried prior to extraction.  
     
     
         11 . A solid procatalyst composition for use in a Ziegler-Natta olefin polymerization catalyst composition prepared according to the method of  claim 1 .  
     
     
         12 . A Ziegler-Natta olefin polymerization catalyst composition comprising a solid procatalyst composition of  claim 11 , 
 a cocatalyst; and    a selectivity control agent.    
     
     
         13 . A process for polymerizing an olefin monomer comprising contacting the olefin monomer under polymerization conditions with a Ziegler-Natta olefin polymerization catalyst composition according to  claim 12 .  
     
     
         14 . An olefin polymer prepared by the process recited in  claim 13.