Ethylene polymerization process

Abstract

A gas phase polymerization of ethylene is disclosed. The process uses a single-site catalyst containing at least one heteroatomic ligand selected from boraaryl, azaborolinyl, pyridinyl, pyrrolyl, indolyl, indenoindolyl, carbazolyl, and quinolinyl. The catalysts are immobilized onto a support. The process comprises polymerizing an ethylene that contains from about 5 to about 15 mole % of a C 3 -C 10 α-olefin and gives polyethylene having a reduced viscosity.

We claim:  
     
         1 . A process that comprises polymerizing ethylene containing about 5 to about 15 mole % of a C 3 -C 10  α-olefin in gas phase in the presence of a supported catalyst comprising: 
 (a) an organometallic compound that contains at least one indenoindolyl ligand;  
 (b) an optional activator; and  
 (c) a support;  
 wherein the polymer produced has a density within the range of about 0.890 to about 0.930 g/mL.  
 
     
     
         2 . The process of    claim 1    wherein the polymerization is performed at a temperature within the range of about 50° C. to about 250° C.  
     
     
         3 . The process of    claim 1    wherein the C 3 -C 10  α-olefin is selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and mixtures thereof.  
     
     
         4 . The process of    claim 1    wherein the support is selected from the group consisting of inorganic oxides and chlorides, and organic polymer resins.  
     
     
         5 . The process of    claim 1    wherein the activator is selected from the group consisting of alumoxanes, alkyl aluminums, alkyl aluminum halides, anionic compounds of boron or aluminum, trialkylboron compounds, and triarylboron compounds.  
     
     
         6 . The process of    claim 1    wherein the process is performed at a pressure within the range of about 300 psi to about 5,000 psi.  
     
     
         7 . The process of    claim 1    wherein the polymer produced has a density within the range of about 0.900 to about 0.920 g/mL.