Ethylene polymer and processes for obtaining it

US6201078A · kind A · utility

Assignee

• Solvay Polyolefins Europe-Belgium (Societe Anonyme) · US

Inventors

• Jacques Breulet · Wezembeek-Oppem, BE
• Benoit Koch · Hannut, BE
• Michel Promel · Brussels, BE
• Jiang Bian · Brussels, BE
• Olivier Lhost · Havré, BE

Key dates

• Filing date: Apr 18, 1996
• Grant date: Mar 13, 2001
• Expiry date: Apr 18, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F2410/04
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Ethylene polymer having a die swell ratio (R.sub.B) of at least 1.4, a resistance to crazing under stress (ESCR) of at least 55 h and a melt index (MI.sub.5) of at least 0.2 g/10 min. Processes for obtaining this ethylene polymer using different catalytic systems, the first based on titanium and zirconium used in a polymerization in two reactors; the second consisting of a mixture of a titanium catalyst and a titanium and zirconium catalyst, used in a polymerization in two reactors; the third based on chromium on a support comprising at least two constituents chosen from silica, alumina and aluminum phosphates, used in a polymerization in a single or in two reactors.