PROCESS FOR THE PREPARATION OF HIGH PURITY PROPYLENE POLYMERS

摘要

A process for the preparation of high purity propylene polymers carried out in the presence of a catalyst comprising the product obtained by contacting:
(a) a solid catalyst component comprising Mg, Ti and at least a first internal electron donor compound (HD) selected among the succinates and a second internal electron donor compound (2ID) selected among the 1,3-diethers, wherein the molar ratio of first internal donor over second internal donor 1ID:2ID is comprised between 4:6 and 9:1, with(b) an organo-aluminium compound, and optionally with(c) an external electron donor compound,

said process being carried out at a temperature equal or higher than 78° C. and by employing a molar ratio of organo-aluminum compound over solid catalyst component (b):(a) of lower than 5.

主权项

1. A process for the preparation of high purity propylene (co)polymers comprising (co)polymerizing propylene in the presence of a catalyst system comprising the product obtained by contacting
(a) a solid catalyst component comprising Mg, Ti and at least a first internal electron donor compound (lID) selected among the succinates and a second internal electron donor compound (2ID) selected among the 1,3-diethers, wherein the molar ratio of first internal donor over second internal donor 1ID:2ID is comprised between 4:6 and 9:1, with (b) an organo-aluminium compound, and optionally with (c) an external electron donor compound, said process being carried out at a temperature equal or higher than 78° C., preferably comprised between 78° C. and 90° C., and by employing a weight ratio of organo-aluminum compound over propylene lower than 0.020, preferably comprised between 0.020 and 0.005 Kg/tonn.