Borealis A/s

Neste Oy

Ismo Pentti

Pauli Leskinen

Ali Harlin

Jukka Koskinen

Henrik Andtsjo

Henrik Andtsj&ouml;

A process for homo or copolymerizing propylene, wherein propylene is polymerized in the presence of a catalyst at an elevated temperature in a reaction medium in which a major part of the reaction medium is propylene and the polymerization is carried in at least one CSTR or loop reactor, where the polymerization is carried out at a temperature and a pressure which are above the corresponding critical temperature and the pressure of the reaction medium and were the residence time is at least 15 minutes. The process can also have a subcritical loop polymerization before the supercritical stage polymerization or gas phase polymerization after the supercritical stage polymerization.

Process for making propylene homo or copolymers

A process for homo or copolymerizing propylene, wherein propylene is polymerized in the presence of a catalyst at an elevated temperature in a reaction medium in which a major part of the reaction medium is propylene and the polymerization is carried in at least one CSTR or loop reactor, where the polymerization is carried out at a temperature and a pressure which are above the corresponding critical temperature and the pressure of the reaction medium and where the residence time is at least 15 minutes. The process can also comprise a supercritical loop polymerization before the supercritical stage polymerization or a gas phase polymerization after the supercritical stage polymerization.

The present invention concerns prepolymerized catalyst composition for polymerization of .beta.-olefins, a process for the preparation thereof and a process for polymerization of .beta.-olefins. According to the polymerization process a procatalyst composition containing a transition metal is prepolymerized with a monomer in order to produce a prepolymerized Ziegler-Natta type catalyst composition and said catalyst composition is contacted with an alpha-olefin monomer, in particular with ethylene or propylene, for preparing a polymer. According to the invention the procatalyst composition is preferably prepolymerized in a medium which is inert to the catalyst components, the viscosity of the medium being so high that the catalyst does not substantially settle in this medium. Because the catalyst composition according to the invention does not have to be dried before being fed into the medium, its activity is high before and during polymerization.

Process for the preparation of repolymerized catalyst composition and a

The present invention concerns prepolymerized catalyst composition for polymerization of .alpha.-olefins, a process for the preparation thereof and a process for polymerization of .alpha.-olefins. According to the polymerization process a procatalyst composition containing a transition metal is prepolymerized with a monomer in order to produce a prepolymerized Ziegler-Natta type catalyst composition and said catalyst composition is contacted with an alpha-olefin monomer, in particular with ethylene or propylene, for preparing a polymer. According to the invention the procatalyst composition is preferably prepolymerized in a medium which is inert to the catalyst components, the viscosity of the medium being so high that the catalyst does not substantially settle in this medium. Because the catalyst composition according to the invention does not have to be dried before being fed into the medium, its activity is high before and during polymerization.

Prepolymerized catalyst composition, a process for the preparation

In conventional spraying methods the problem in the preparation of small carrier particles aimed for the polymerization is that the drops constituting the prestages of the particles agglomerate or form otherwise in different sizes, whereby the size distribution of the carrier particles becomes too broad. This leads due to the so-called replica phenomenon to a polymer product having also a too broad particle size distribution. In the present invention the carrier is prepared by spraying a liquid containing a carrier through a nozzle into inert gas so that its first forms small droplets, which then solidify to small carrier particles. The desired narrow particle size distribution is provided by feeding a liquid containing a carrier through a nozzle, in which or in connection with which the liquid drops by means of the standing sonic waves in the ultrasonic range into small droplets of uniform size. The droplets of uniform size solidify then into small carrier particles of equally uniform size.

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Kulloo, Finland

Ismo Pentti