Production of multimodal polyethylene

US6479589B2 · kind B2 · utility

Assignee

• Fina Research, S.A. · BE

Inventors

• Guy Debras · Les Bons Villers, BE
• Abbas Razavi · Mons, BE
• Jacques Michel · Limeil-Brévannes, FR

Key dates

• Filing date: Jan 4, 2002
• Grant date: Nov 12, 2002
• Expiry date: Jan 4, 2022

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08L2314/06
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A process for preparing polyethylene, including contacting ethylene monomer and an alpha-olefin comonomer to produce a first polyethylene (HLMI of ≦0.5 g/10 min, density ≦0.925 g/ml). The a catalyst system is a bis tetrahydroindenyl formula (IndH4)2R″MQ2 wherein each Ind is the same or different and is indenyl or substituted indenyl, R″ is a bridge which comprises a C1-C20 alkylene radical, a dialkyl germanium or silicon or siloxane, or an alkyl phosphine or amine radical, which bridge is substituted or unsubstituted, M is a Group IVB transition metal or vanadium and each Q is hydrocarbyl having 1 to 20 carbon atoms or halogen. The polyethylene resin having multimodal molecular weight distribution is formed by mixing the first polyethylene with a second polyethylene (produced with a different catalyst and with a lower molecular weight and higher density than the first polyethylene).