PROCESS FOR THE PRODUCTION OF AN ALPHA-OLEFIN POLYMER
The present invention is directed to a process for the production of an alpha-olefin polymer, which process comprises feeding of at least one alpha-olefin to a mechanically stirred bed gas phase reactor containing particles of the alpha-olefin polymer and polymerizing the alpha-olefin in the presence of a catalyst based on a titanium compound and a magnesium compound, an aluminum-alkyl compound and optionally an organosilane donor, in which process an amount of less than 100 ppm of at least one compound selected from the group of ethoxylated amines, fatty acid esters, diethanol amides, ethoxylated alcohols, alkylsulfonates and alkylphosphates is present during the polymerization.
1 . Process for the production of an alpha-olefin polymer, which process comprises feeding of at least one alpha-olefin to a mechanically stirred bed gas phase reactor containing particles of the alpha-olefin polymer and polymerizing the alpha-olefin in the presence of a catalyst based on a titanium compound and a magnesium compound, an aluminum-alkyl compound and optionally an organosilane donor, in which process an amount of less than 100 ppm of at least one compound selected from the group of ethoxylated amines, fatty acid esters, diethanol amides, ethoxylated alcohols, alkylsulfonates and alkylphosphates is present during the polymerization.
2 . Process according to claim 1 , wherein the amount of the said at least one compound is between 5 and 80 ppm.
3 . Process according to claim 1 , wherein the said at least one compound is an ethoxylated amine, preferably an N-alkyl-diethanolamine.
4 . Process according to claim 1 , wherein an alpha-olefin having from 3 to 5 carbon atoms is present in the gas phase in a molar concentration of from 20 to 90% with respect to the total gas.
5 . Process according to claim 1 , wherein the alpha-olefin is propylene.
6 . Process according to claim 1 , characterized in that the titanium compound comprises at least one halide-Ti bond.
7 . Process according to claim 1 , wherein the aluminum alkyl compound is selected from triethylaluminium or other trialkylaluminium.
8 . Process according to claim 1 , wherein the gas phase reactor has a gas phase which is at least partly recirculated over the reactor.
9 . Process according to claim 1 , wherein the stirred bed gas phase reactor is horizontally oriented.
10 . Process according to claim 1 , wherein the stirred bed gas phase reactor is vertically oriented.
11 . Process according to claim 2 , wherein:
the said at least one compound is an ethoxylated amine, preferably an N-alkyl-diethanolamine;
an alpha-olefin having from 3 to 5 carbon atoms is present in the gas phase in a molar concentration of from 20 to 90% with respect to the total gas;
the alpha-olefin is propylene;
the titanium compound comprises at least one halide-Ti bond; and
the aluminum alkyl compound is selected from triethylaluminium or other trialkylaluminium.
12 . Process according to claim 11 , wherein the gas phase reactor has a gas phase which is at least partly recirculated over the reactor.
13 . Process according to claim 11 , wherein the stirred bed gas phase reactor is horizontally oriented.
14 . Process according to claim 12 , wherein the stirred bed gas phase reactor is horizontally oriented.
15 . Process according to claim 11 , wherein the stirred bed gas phase reactor is vertically oriented.
16 . Process according to claim 12 , wherein the stirred bed gas phase reactor is vertically oriented.