Process for the preparation of an unsupported, solid metallocene catalyst system and its use in polymerization of olefins

An unsupported, heterogeneous olefin polymerization catalyst system, obtainable by the steps comprising:

• a) preparing a solution of catalyst components, including an aluminoxane, a compound being effective to form clathrates with aluminoxane and an organometallic compound of a transition metal of Group 3 to 10 of the Periodic Table (IUPAC 2007) or of an actinide or lanthanide, in a hydrocarbon solvent,
• yielding a two phase system with an upper solvent layer, which is separated,
• b) preparing a liquid/liquid emulsion system comprising a continuous phase in which said solution of the catalyst components forms a dispersed phase in the form of droplets,
• c) solidifying said dispersed phase to convert said droplets to solid particles and optionally recovering said particles to obtain said catalyst system.

A polyolefin obtainable by the steps comprising:

• preparing of polyolefins comprising polymerizing at least one olefin monomer in the presence of an olefin polymerization catalyst system,
• wherein the olefin polymerization catalyst system comprises an organometallic compound of a transition metal of Group 3 to 10 of the Periodic Table (IUPAC 2007) or of an actinide or lanthanide in the form of solid particles comprising the steps of:
• a) preparing a solution of catalyst components, including an aluminoxane, a compound being effective to form clathrates with aluminoxane and an organometallic compound of a transition metal of Group 3 to 10 of the Periodic Table (IUPAC 2007) or of an actinide or lanthanide, in a hydrocarbon solvent,
• yielding a two phase system with an upper solvent layer, which is separated,
• b) preparing a liquid/liquid emulsion system comprising a continuous phase in which said solution of the catalyst components forms a dispersed phase in the form of droplets,
• c) solidifying said dispersed phase to convert said droplets to solid particles and optionally recovering said particles to obtain said catalyst system.