Manufacture of polyethylenes

Abstract

Blends of two or more polyethylenes are made by reacting ethylene with an oligomerization catalyst that forms α-olefins, and two polymerization catalysts, one of which under the process conditions copolymerizes ethylene and α-olefins, and the other of which under process conditions does not readily copolymerize ethylene and α-olefins. The blends may have improved physical properties and/or processing characteristics.

What is claimed is:  
     
         1 . A process for producing a blend of two or more polyethylenes, comprising the step of contacting: 
 (1) ethylene;    (2) an active ethylene oligomerization catalyst under conditions to oligomerize at least a portion of the ethylene to one or more α-olefins of the general formula R 18 CH═CH 2 , wherein R 18  is alkyl containing an even number of carbon atoms;    (3) a first active polymerization catalyst under conditions to copolymerize ethylene and the α-olefins generated from the active ethylene oligomerization catalyst; and    (4) a second active polymerization catalyst under conditions to polymerize ethylene, but not readily copolymerize ethylene and α-olefins.    
     
     
         2 . The process as recited in  claim 1  wherein the active ethylene oligomerization catalyst is an Fe complex of a ligand of the general formula (I)  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 1 , R 2  and R 3  are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or an inert functional group, provided that any two of R 1 , R 2  and R 3  vicinal to one another taken together may form a ring;  
 R 4  and R 5  are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or an inert functional group;  
 R 6  and R 7  are each independently an aryl or substituted aryl having a first ring atom bound to the imino nitrogen, provided that: 
 in R 6 , a second ring atom adjacent to said first ring atom is bound to a halogen, a primary carbon group, a secondary carbon group or a tertiary carbon group; and further provided that  
 in R 6 , when said second ring atom is bound to a halogen or a primary carbon group, none, one or two of the other ring atoms in R 6  and R 7  adjacent to said first ring atom are bound to a halogen or a primary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom; or  
 in R 6 , when said second ring atom is bound to a secondary carbon group, none, one or two of the other ring atoms in R 6  and R 7  adjacent to said first ring atom are bound to a halogen, a primary carbon group or a secondary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom; or  
 in R 6 , when said second ring atom is bound to a tertiary carbon group, none or one of the other ring atoms in R 6  and R 7  adjacent to said first ring atom are bound to a tertiary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom.  
 
 
     
     
         3 . The process as recited in  claim 2  wherein the active ethylene oligomerization catalyst is an Fe complex of a ligand of the general formula (II):  
       
         
           
           
               
               
           
         
       
       wherein: 
 each of R 1 , R 2 , R 3 , R 4 , R 5 , R 9 , R 10 , R 11 , R 14 , R 15  and R 16  is independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl and an inert functional group; and  
 R 8  is a primary carbon group, a secondary carbon group or a tertiary carbon group;  
 provided that:  
 when R 8  is a primary carbon group none, one or two of R 12 , R 13  and R 17  are independently a primary carbon group, an inert functional group or a trihalo tertiary carbon group, and the remainder of R 12 , R 13  and R 17  are hydrogen;  
 when R 8  is a secondary carbon group, none or one of R 12 , R 13  and R 17  is a primary carbon group, a secondary carbon group, a trihalo tertiary carbon group or an inert functional group, and the remainder of R 12 , R 13  and R 17  are hydrogen;  
 when R 8  is a tertiary carbon group all of R 12 , R 13  and R 17  are hydrogen;  
 any two of R 1 , R 2  and R 3  vicinal to one another, taken together may form a ring; and  
 any two of R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16  and R 17  vicinal to one another, taken together may form a ring.  
 
     
     
         4 . The process as recited in  claim 1  wherein the second active polymerization catalyst is chemically different than the first active polymerization catalyst, and has little or no tendency to copolymerize ethylene and α-olefins.  
     
     
         5 . The process as recited in  claim 1  wherein the second active polymerization catalyst is an Fe complex of a ligand of the general formula (III):  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 1 , R 2 , R 3 , R 4  and R 5  are each independently hydrogen hydrocarbyl, substituted hydrocarbyl, or an inert functional group, provided that any two of R 1 , R 2  and R 3  vicinal to one another, taken together may form a ring; and  
 R 6  and R 7  are aryl or substituted aryl.  
 
     
     
         6 . The process as recited in  claim 1  wherein the first polymerization catalyst is a metallocene-type catalyst.  
     
     
         7 . The process as recited in  claim 1  wherein the oligomerization catalyst, first polymerization catalyst and second polymerization catalyst are supported.  
     
     
         8 . The process as recited in  claim 7  carried out in the gas phase.  
     
     
         9 . The process as recited in  claim 1  wherein the polyethylenes are homopolyethylenes.  
     
     
         10 . The process as recited in  claim 2  wherein the second active polymerization catalyst is chemically different than the first active polymerization catalyst, and has little or no tendency to copolymerize ethylene and α-olefins.  
     
     
         11 . The process as recited in  claim 10  wherein the first polymerization catalyst is a metallocene-type catalyst, and the second active polymerization catalyst is an Fe complex of a ligand of the general formula (III):  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 1 , R 2 , R 3 , R 4  and R 5  are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or an inert functional group, provided that any two of R 1 , R 2  and R 3  vicinal to one another, taken together may form a ring; and  
 R 6  and R 7  are aryl or substituted aryl.  
 
     
     
         12 . A polymerization catalyst component, comprising: 
 (a) an oligomerization catalyst that oligomerizes ethylene to one or more α-olefins of the formula H 2 C═CHR 18 , wherein R 18  is an alkyl containing an even number of carbon atoms;    (b) a first polymerization catalyst that is capable of copolymerizing ethylene and one or more α-olefins of the formula H 2 C═CHR 18 ; and    (c) a second polymerization catalyst chemically distinct from the first polymerization catalyst, that is capable of polymerizing ethylene but does not readily copolymerize ethylene and α-olefins.    
     
     
         13 . The polymerization catalyst component as recited in  claim 12 , further comprising (d) one or more catalyst supports onto which one or more of (a), (b) and/or (c) has been supported.  
     
     
         14 . The polymerization catalyst component as recited in  claim 12  wherein the ethylene oligomerization catalyst is an Fe complex of a ligand of the general formula (I)  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 1 , R 2  and R 3  are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or an inert functional group, provided that any two of R 1 , R 2  and R 3  vicinal to one another taken together may form a ring;  
 R 4  and R 5  are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or an inert functional group;  
 R 6  and R 7  are each independently an aryl or substituted aryl having a first ring atom bound to the imino nitrogen, provided that:  
 in R 6 , a second ring atom adjacent to said first ring atom is bound to a halogen, a primary carbon group, a secondary carbon group or a tertiary carbon group; and further provided that 
 in R 6 , when said second ring atom is bound to a halogen or a primary carbon group, none, one or two of the other ring atoms in R 6  and R 7  adjacent to said first ring atom are bound to a halogen or a primary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom; or  
 in R 6 , when said second ring atom is bound to a secondary carbon group, none, one or two of the other ring atoms in R 6  and R 7  adjacent to said first ring atom are bound to a halogen, a primary carbon group or a secondary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom; or  
 in R 6 , when said second ring atom is bound to a tertiary carbon group, none or one of the other ring atoms in R 6  and R 7  adjacent to said first ring atom are bound to a tertiary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom.  
 
 
     
     
         15 . The polymerization catalyst component as recited in  claim 14  wherein the ethylene oligomerization catalyst is an Fe complex of a ligand of the general formula (II):  
       
         
           
           
               
               
           
         
       
       wherein: 
 each of R 1 , R 2 , R 3 , R 4 , R 5 , R 9 , R 10 , R 11 , R 14 , R 15  and R 16  is independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl and an inert functional group; and  
 R 8  is a primary carbon group, a secondary carbon group or a tertiary carbon group;  
 provided that:  
 when R 8  is a primary carbon group none, one or two of R 12 , R 13  and R 17  are independently a primary carbon group, an inert functional group or a trihalo tertiary carbon group, and the remainder of R 12 , R 13  and R 17  are hydrogen;  
 when R 8  is a secondary carbon group, none or one of R 12 , R 13  and R 17  is a primary carbon group, a secondary carbon group, a trihalo tertiary carbon group or an inert functional group, and the remainder of R 12 , R 13  and R 17  are hydrogen;  
 when R 8  is a tertiary carbon group all of R 12 , R 13  and R 17  are hydrogen;  
 any two of R 1 , R 2  and R 3  vicinal to one another, taken together may form a ring; and  
 any two of R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16  and R 17  vicinal to one another, taken together may form a ring.  
 
     
     
         16 . The polymerization catalyst component as recited in  claim 12  wherein the second active polymerization catalyst is an Fe complex of a ligand of the general formula (III):  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 1 , R 2 , R 3 , R 4  and R 5  are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or an inert functional group, provided that any two of  
 R 1 , R 2  and R 3  vicinal to one another, taken together may form a ring; and  
 R 5  and R 7  are aryl or substituted aryl.  
 
     
     
         17 . The polymerization catalyst component as recited in  claim 12  wherein the first polymerization catalyst is a metallocene-type catalyst.  
     
     
         18 . The polymerization catalyst component as recited in  claim 12  wherein the first polymerization catalyst is a metallocene-type catalyst, and the second active polymerization catalyst is an Fe complex of a ligand of the general formula (III):  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 1 , R 2 , R 3 , R 4  and R 5  are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or an inert functional group, provided that any two of R 1 , R 2  and R 3  vicinal to one another, taken together may form a ring; and  
 R 6  and R 7  are aryl or substituted aryl.  
 
     
     
         19 . The polymerization catalyst component as recited in  claim 18 , further comprising (d) one or more catalyst supports onto which one or more of (a), (b) and/or (c) has been supported.  
     
     
         20 . A polymer blend comprising: 
 (a) a first polyethylene that contains at least three different branches of the formula —(CH 2 CH 2 ) n H, wherein n is an integer of 1 or more, and    (b) a second polyethylene that is different from the first polyethylene, in a weight ratio of about 1:4 to about 4:1 based on the total weight of the first and second polyethylenes, and provided that said second polyethylene has a melting point at least 20° C. higher than said first polyethylene, or said second polyethylene has a heat of fusion at least 50 J/g greater than said first polyethylene, or both.    
     
     
         21 . The polymer blend of  claim 20  wherein the first and second polyethylenes are homopolyethylenes.  
     
     
         22 . A polymer blend comprising: 
 (a) a third polyethylene having a density of less than 0.93 g/mL, containing at least 2 ethyl branches, at least 2 hexyl or longer branches and at least one butyl branch per 1000 methylene groups, and provided that said third polyethylene has fewer than 5 methyl branches per 1000 methylene groups; and    (b) a fourth polyethylene having a density of 0.93 g/mL or more.    
     
     
         23 . The polymer blend of  claim 22  wherein the third and fourth polyethylenes are homopolyethylenes.  
     
     
         24 . A polymer blend comprising: 
 (a) a fifth polyethylene containing about 20 to about 150 branches of the formula —(CH 2 CH 2 ) n H per 1000 methylene groups, wherein n is an integer of 1 to 100, provided that said fifth polyethylene has less than about 20 methyl branches per 1000 methylene groups; and    (b) a sixth polyethylene that is different from the fifth polyethylene and has a density of about 0.93 g/mL or more.    
     
     
         25 . The polymer blend of  claim 24  wherein the fifth and sixth polyethylenes are homopolyethylenes.