Olefin polymerisation catalyst

Abstract

The present invention relates to particulate olefin polymerisation catalyst components comprising an alkaline earth metal, a compound of a transition metal and an electron donor, characterized in that the catalyst particle size distribution of the catalyst component is essentially monomodal and has a SPAN value below 1.2, where SPAN is defined as: (Particle diameter at 90% cumulative size)-(Particle diameter at 10% cumulative size)/(Particle diameter at 50% cumulative size). The particulate olefin polymerisation catalyst components of the present invention are provided by a process which comprises preparing a solution of a complex of an alkaline earth metal and an electron donor by reacting a compound of said metal with said electron donor or a precursor thereof in an organic liquid reaction medium, reacting said complex in the solution form with a compound of a transition metal to produce a dispersion, wherein the dispersed phase predominantly contains the alkaline earth metal in said complex, and solidifying said dispersed phase to obtain said catalyst component, and is characterized in that a second organic liquid medium is added to the reactor after mixing the alkaline earth metal complex with the transition metal compound.

1 . A process for producing an olefin polymerisation catalyst component in the form of particles, which comprises
 preparing a solution of a complex of an alkaline earth metal and an electron donor by reacting a compound of said metal with said electron donor or a precursor thereof in an organic liquid medium,   reacting said complex in solution form with a compound of a transition metal wherein a dispersion is formed, wherein the dispersed phase predominantly contains the alkaline earth metal in said complex, and   solidifying said dispersed phase to obtain said catalyst component,   and wherein
 a second organic liquid medium is added to the reactor after mixing the alkaline earth metal complex with the transition metal compound. 
   
     
     
         2 . The process according to  claim 1 , wherein the organic liquid medium comprises C 6 -C 10  aromatic hydrocarbons. 
     
     
         3 . The process according to  claim 1 , wherein the organic liquid medium comprises toluene. 
     
     
         4 . The process according to  claim 1 , wherein the second organic liquid medium is an aliphatic hydrocarbon selected from straight, branched or cyclic hydrocarbons having 5, 6, 7 or 8 C-atoms. 
     
     
         5 . The process according to  claim 1 , wherein the second organic liquid medium is selected from pentane, hexane, heptane, octane or cyclohexane or mixtures or isomers thereof. 
     
     
         6 . The process according to  claim 1 , wherein the second organic liquid medium is heptane. 
     
     
         7 . The process according to  claim 1 , wherein said transition metal is a Group 4 metal. 
     
     
         8 . The process according to  claim 1 , wherein said alkaline earth metal is magnesium. 
     
     
         9 . The process according to  claim 1 , wherein said dispersion is composed of a dispersed phase which is TiCl 4 /toluene-insoluble and has a molar ratio of Group 4 metal/alkaline earth metal of greater than 0.1 and less than 10 and a continuous phase which is less dense than the dispersed phase and has a molar ratio of Group 4 metal/alkaline earth metal of 10 to 100. 
     
     
         10 . The process according to  claim 9 , wherein the molar ratio of Group 4 metal/alkaline earth metal in said continuous phase is 20 to 80. 
     
     
         11 . The process according to  claim 9 , wherein the molar ratio of Group 4 metal/alkaline earth metal in said continuous phase is 45 to 75. 
     
     
         12 . The process according to  claim 1 , wherein said complex and said transition metal compound are reacted at a temperature of 10 to 60° C. 
     
     
         13 . The process according to  claim 1 , wherein the solidification of said dispersed phase is effected by heating. 
     
     
         14 . The process according to  claim 1 , wherein said electron donor is an aromatic carboxylic acid ester. 
     
     
         15 . The process according to  claim 14 , wherein said electron donor is di(ethyl-hexyl) phthalate. 
     
     
         16 . The process according to  claim 1 , wherein said electron donor is formed in situ by reaction of an aromatic carboxylic acid chloride precursor with a C 2 -C 16  alkanol and/or diol. 
     
     
         17 . The process according to  claim 1 , wherein the dispersion is maintained by agitation. 
     
     
         18 . The process according to  claim 1 , wherein the dispersion is maintained by the addition of a dispersion stabilizer. 
     
     
         19 . The process according to  claim 18 , wherein said dispersion stabilizer comprises a surfactant. 
     
     
         20 . The process according to  claim 19 , wherein said surfactant comprises an acrylic or methacrylic polymer. 
     
     
         21 . The process according to  claim 9 , wherein the molar ratio of Group 4 metal/alkaline earth metal in said dispersed phase is 2 to 4 and that of the continuous phase is 55 to 65. 
     
     
         22 . The process according to  claim 21 , wherein the ratio of the molar ratio of Group 4 metal/alkaline earth metal in the continuous phase to that of the dispersed phase is at least 10. 
     
     
         23 . The process according to  claim 1 , wherein the dispersion is heated to a temperature of 70 to 150° C. to solidify said dispersed phase. 
     
     
         24 . The process according to  claim 23 , wherein the temperature to which the dispersion is heated is to 90 to 110° C. 
     
     
         25 . The process according to  claim 1 , wherein the preparation of the alkaline earth metal complex is carried out at a temperature of 20 to 80° C. 
     
     
         26 . The process according to  claim 25 , wherein the alkaline earth metal is magnesium and the preparation of the magnesium complex is carried out at a temperature of 50 to 70° C. 
     
     
         27 . The process according to  claim 7 , wherein said Group 4 metal is titanium. 
     
     
         28 . The process according to  claim 7 , wherein said compound of a Group 4 metal is a halide. 
     
     
         29 . The process according to  claim 1 , wherein said transition metal is a Group 5 metal and/or a Group 6 metal. 
     
     
         30 . The process according to  claim 1 , wherein said transition metal is Cu, Fe, Co, Ni and/or Pd.