Ziegler-natta catalyst compositions for producing polyethylenes with a high molecular weight tail and methods of making the same

Abstract

Methods of preparing a polymerization catalyst component is provided, in which a magnesium component, a Lewis acid solubilizing component, a titanium compound, optionally a transition metal compound different than the titanium compound, and typically an inert filler are combined in a slurrying agent and spray-dried to produce a catalyst precursor in the form of a substantially spherical and porous solid particle. The methods and catalysts of this disclosure can provide ethylene homopolymer and copolymer resins having a high molecular weight tail and a broadened molecular weight distribution as compared to more traditional Ziegler-Natta catalysts.

1 . A method of preparing a catalyst component, the method comprising:
 a) contacting in a slurrying agent:
 i) at least one magnesium dihydrocarbyl oxide; 
 ii) at least one Lewis acidic solubilizing agent; and 
 iii) at least one titanium compound; 
   
       and
 b) spray drying the slurry of step a) to evaporate the slurrying agent and to produce solid particles; 
 where the magnesium dihydrocarbyl oxide and the titanium compound are present in the slurry in any molar ratio. 
 
     
     
         2 . The method according to  claim 1 , where step a) of contacting in a slurrying agent components i), ii), and iii) further comprises contacting with:
 iv) at least one transition metal compound different from the titanium compound, where the transition metal is selected from the Groups 4-6 metals.   
     
     
         3 . The method according to  claim 2 , where the transition metal compound different from the titanium compound is selected from:
 a) Zr(OR 4 ) b Cl 4-b , Hf(OR 4 ) b Cl 4-b , VOCl 3 , or any combination thereof, where b is an integer from 0 to 4, and R 4  in each occurrence is an alkyl group having from 1 to 12 carbon atoms;   b) Ti(OR 5 ) c X 1   4-c , or any combination of compounds of this formula, where X 1  is Cl, Br, or I; c is an integer from 0 to 3; and R 5  in each occurrence is an alkyl group having from 1 to 12 carbon atoms;   c) TiX 2   d  where X 2  is Cl, Br, or I and d is a number from greater than 0 to less than 4; or   d) any combination thereof.   
     
     
         4 . The method according to  claim 1 , where step a) of contacting in a slurrying agent components i), ii), and iii) further comprises contacting with:
 v) a non-porous filler.   
     
     
         5 . The method according to  claim 1 , where the slurrying agent is selected from an alcohol having up to 4 carbon atoms or any combination of alcohols having up to 4 carbon atoms. 
     
     
         6 . The method according to  claim 1 , where the Lewis acid solubilizing agent is carbon dioxide and the slurrying agent is an alcohol having from 1 to 4 carbon atoms. 
     
     
         7 . The method according to  claim 1 , where:
 the magnesium dihydrocarbyl oxide has the formula Mg(OR 1 ) 2  where R 1  in each occurrence, is selected independently from an alkyl having up to 6 carbon atoms inclusive; and   the Lewis acidic solubilizing agent is selected from carbon dioxide, sulfur dioxide, formaldehyde, Al(OR 2 ) 3 , B(OR 2 ) 3 , or any combination thereof, where R 2  in each occurrence is selected independently from an alkyl having up to 6 carbon atoms inclusive.   
     
     
         8 . The method according to  claim 1 , further comprising step c), as follows:
 c) contacting the solid particles of step b) with at least one halogenating agent under conditions that partially halogenate the catalyst precursor.   
     
     
         9 . The method according to  claim 1 , further comprising step c), as follows:
 c) contacting the solid particles of step b) with:
 i) at least one mild first halogenating agent and at least one strong second halogenating agent in succession, under conditions which partially halogenate the catalyst precursor; or 
 ii) at least one strong halogenating agent under conditions which partially halogenate the catalyst precursor. 
   
     
     
         10 . A catalyst system comprising:
 a) a catalyst component prepared according to  claim 1 ;   b) a halogenating agent; and   c) an activating co-catalyst.   
     
     
         11 . The catalyst system according to  claim 10 , where the activating co-catalyst is selected from at least one compounds of the formula AlR 10   3 , where R 10  in each occurrence is independently a saturated hydrocarbon groups having from 1 to 14 carbon atoms, optionally substituted with one or more substituents which are inert under the polymerization reaction conditions employed. 
     
     
         12 . A method of preparing a catalyst component, the method comprising:
 a) contacting in a slurrying agent:
 i) at least one magnesium dihydrocarbyl oxide; 
 ii) at least one Lewis acidic solubilizing agent; 
 iii) at least one titanium compound; and 
 iv) at least one non-porous filler; 
   b) spray drying the slurry of step a) to evaporate the slurrying agent and to produce solid particles;   
       and
 c) treating the solid particles of step b) with at least one halogenating agent; 
 where the magnesium dihydrocarbyl oxide, the titanium compound, and the optional transition metal compound different from the titanium compound are present in the slurry in any molar ratio. 
 
     
     
         13 . The method according to  claim 12 , where step a) of contacting in a slurrying agent components i), ii), iii), and iv) further comprises contacting with:
 v) at least one transition metal compound different from the titanium compound, where the transition metal is selected from the Groups 4-6 metals.   
     
     
         14 . A catalyst system comprising:
 a) catalyst component prepared according to  claim 12 ; and   b) an activating co-catalyst selected from at least one compounds of the formula AlR 10   3 , where R 10  in each occurrence is independently a saturated hydrocarbon groups having from 1 to 14 carbon atoms, optionally substituted with one or more substituents which are inert under the polymerization reaction conditions employed.   
     
     
         15 . A catalyst component comprising the contact product of:
 a) a spray-dried mixture or reaction product of:
 i) at least one magnesium dihydrocarbyl oxide; 
 ii) at least one Lewis acidic solubilizing agent; 
 iii) at least one titanium compound; 
 iv) at least one transition metal compound different from the titanium compound, where the transition metal is selected from the Groups 4-6 metals; and 
 v) at least one non-porous filler; 
   b) at least one strong second halogenating agent;   where contacting occurs under conditions that partially or exhaustively halogenate the spray-dried mixture or reaction product.   
     
     
         16 . The catalyst component according to  claim 15 , where the contact product further comprises the contact product of components a) and b) with:
 c) at least one mild first halogenating agent.   
     
     
         17 . The catalyst component according to  claim 14 , where contacting occurs under conditions that partially halogenate the spray-dried mixture or reaction product.