Patent attributes
The present invention refers to a metallocene catalyst component for producing polyolefins according to formula (I) R″s (CpRn)g (CpRn) M Q3-g (I) or according to formula (II) R″(CpRn)MeXQ (II) wherein—each Cp is a substituted or unsubstituted cyclopentadienyl ring with the bridge-head position of at least one of the cyclopentadienyl rings being occupied by a silicon atom;—each R is the same or different and is hydrogen or a hydrocarbyl radical such as alkyl, alkenyl, aryl, alkylaryl or arylalkyl radical containing from 1 to 20 carbon atoms or two carbon atoms are joined together to form a C4-C6 ring; —R″ is a structural bridge between two Cp rings;—M is a group IIIB, IVB, VB or VIB metal;—Q is a hydrocarbyl radical such as aryl, alkyl, alkenyl, alkylaryl or arylalkyl radical having from 1 to 20 carbon atoms, a hydrocarboxy radical having from 1 to 20 carbon atoms or a halogen and can be the same or different from each other;—s is 0 or 1, g is 0, 1 or 2 and s is 0 when g is 0, n is 4 when s is 1 and n is 5 when s is 0, —X is an hetero atom ligand with one or two lone pair electrons and selected from the group VA or VIA, substituted or unsubstituted. Said metallocene catalyst component is used in a catalyst system for preparing polyolefins with desired properties.
