Carrier for olefin polymerization catalysts

Abstract

Procedure for the preparation of a solid carrier for olefin polymerization catalysts comprising the steps: a) impregnating a silica with a solution of Mg-chloride in the presence of electron donors, b) drying the impregnated silica obtained in (a) and impregnating it with a solution of Mg-alkyls in SiCl 4 at a temperature from −10 to 20° C., optionally adding a further. amount of electron donors, c) subsequently treating the slurry obtained in (b) at a temperature from 40° C. to reflux temperature, d) drying the carrier obtained in (c). The carrier which is obtained according to the above procedure is advantageously used for the preparation of supported catalysts for the polymerization of olefins

1 . Procedure for the preparation of a solid carrier for olefin polymerization catalysts, comprising the steps: 
 a) impregnating a silica with a solution of Mg-chloride in the presence of electron donors,    b) drying the impregnated silica obtained in (a) and impregnating it with a solution of Mg-alkyls in SiCl 4  at a temperature from −10 to 20° C., optionally adding a further amount of electron donors,    c) subsequently treating the slurry cotained in (b) at a temperature from 40° C. to reflux temperature.    d) drying the carrier obtained in (c).    
     
     
         2 . Procedure according to  claim 1 , wherein an ester is used as a solvent for Mg-chloride.  
     
     
         3 . Procedure according to  claim 2 , wherein the solvent for Mg-chloride is ethyl formiate, ethyl acetate, ethyl propionate, isopropyl acetate or isopropyl propionate  
     
     
         4 . Procedure according to any of  claims 1  to  3 , wherein the silica obtained after the impregnation step (a) contains less than 6% wt of Mg, referred to the final carrier.  
     
     
         5 . Procedure according to any of  claims 1  to  4 , wherein the carrier obtained in step (d) contains 2 to 10% wt, preferably 5 to 8% wt of Mg, referred to the final carrier.  
     
     
         6 . Procedure according to any of  claims 1  to  5 , wherein the silica has a content of OH-groups of 0 to 5 mM/g.  
     
     
         7 . Procedure according to any of  claims 1  to  6 , wherein the silica is spheroidal and porous without a content of free water, and having an average particle size of 15 to 150 micron, a surface area of 100 to 500 m 2 /g, a pore volume of 1.2 to 3 ml/g and an average pore diameter of 20 to 500 angstrom.  
     
     
         8 . Procedure according to any of  claims 1  to  7 , wherein the molar ratio of Mg-alkyl: SiCl 4  is from 1:5 to 1:30.  
     
     
         9 . Procedure according to any of  claims 1  to  8 , wherein phthalic acid esters are used as donors.  
     
     
         10 . Procedure according to  claim 9 , wherein diisobutylphthalate is used as the donor  
     
     
         11 . Procedure according to any of  claims 1  to  10 , wherein the donor is used in an amount of 20 to 100% wt, referred to the silica.  
     
     
         12 . Procedure according to any of  claims 1  to  11 , wherein the Mg-alkyl is a Mg-diethyl, Mg-ethylbutyl, Mg-dihexyl or Mg-butyloctyl.  
     
     
         13 . Procedure for the preparation of a supported catalyst for the polymerization of α-olefins. wherein a carrier (or support) obtained according to any of  claims 1  to  12 , is contacted with a transition metal halide of group IVb, Vb or VIb of the periodic table, and optionally with electron donors.  
     
     
         14 . Process for the preparation of polyolefins by homopolymerization or copolymerization of olefins, wherein a supported catalyst according to  claim 13  is used.