Bp Chemicals Limited

Bp Chimie Societe Anonyme

Alain Blaya

Jean C Bailly

Pierre Crouzet

Stylianos Sandis

Laszlo Havas

The present invention relates to a process for polymerizing or copolymerizing alpha-olefins comprising, on the one hand, a prepolymerization stage by contacting one or more alpha-olefins with a Ziegler catalyst system consisting of a solid catalyst containing essentially atoms of halogen, magnesium and transition metal, and a co-catalyst consisting of an organometallic compound, and, on the other hand, a polymerization or copolymerization stage in a gas phase process by means of a fluidized bed, by contacting one or more alpha-olefins with the prepolymer produced in the first stage, process characterized in that the alpha-olefin prepolymer and polymer or copolymer are in the form of a powder consisting of particles having specific values for the transition metal content and the mean diameter by mass, and characterized in that the particle size distribution of the prepolymer is narrow and easily controlled.

Process for the polymerization and copolymerization of alpha-olefins in

The present invention relates to a process for polymerizing or copolymerizing alpha-olefins comprising, on the one hand, a prepolymerization stage by contacting one or more alpha-olefins with a Ziegler catalyst system consisting of a solid catalyst containing essentially atoms of halogen, magnesium and transition metal, and a co-catalyst consisting of an organomatellic compound, and, on the other hand, a polymerization or copolymerization stage in a gas phase process by means of a fluidized bed, by contacting one or more alpha-olefins with the prepolymer produced in the first stage, process characterized in that the alpha-olefin prepolymer and polymer or copolymer are in the form of a powder consisting of particules having specific values for the transition metal content and the mean diameter by mass, and characterized in that the particle size distribution of the prepolymer is narrow and easily controlled.

The present invention relates to a process for polymerizing or copolymerizing alpha-olefins comprising, on the one hand, a prepolymerization stage by contacting one or more alpha-olefins with a Ziegler catalyst system consisting of a solid catalyst containing essentially atoms of halogen, magnesium and transition metal, and a co-catalyst consisting of an organomatellic compound, and, on the other hand, a polymerization or copolymerization stage in a gas phase process by means of a fluidized bed, by contacting one or more alpha-olefins with the prepolymer produced in the first stage, process characterized in that the alpha-olefin prepolymer and polymer or copolymer are in the form of a powder consisting of particles having specific values for the transition metal content and the mean diameter by mass, and characterized in that the particle size distribution of the prepolymer is narrow and easily controlled.

The present invention relates to catalysts for the polymerization and copolymerization of ethylene, characterized in that they comprise a support based on magnesium chloride and possibly on aluminium chloride, of spheroidal shape, having a mean diameter by mass comprised between 10 and 100 microns and with a narrow particle size distribution, such that the ratio of the mean diameter by mass to the mean diameter by number is less than or equal to 3, on which support there has been precipitated a derivative of a transition metal of groups IV, V and VI of the Periodic Table of Elements, and a polymerization process utilizing the said catalysts.

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Martigues, France

Alain Blaya