Borealis Technology Oy

Borealis A/s

Berggren Oy Ab

Hannu Salminen

Arild Follestad

Kalle Kallio

Hilkka R Knuuttila

Markku Sainio

Harri Hokkanen

Erkki Laiho

Ari Palmroos

Arja Lehtinen

Martti Vähälä

Tarja Soderberg

Martti V&auml;h&auml;l&auml;

Jari Tervonen

Antero Ahvenainen

This invention concerns a process for coating a substrate, and an extrusion coating structure. According to the present process, the coating is provided by producing a bimodal polyethylene composition by subjecting ethylene, optionally with hydrogen and/or comonomers to polymerization or copolymerization reactions in a multistage polymerization sequence of successive polymerization stages. The polymerization reactions are carried out in the presence of a single site catalyst capable of forming a composition which comprises a low molecular weight component with an MFRof 20 g/10 min or more and a density higher than the density of the composition, and a high molecular weight component, said composition having a melt flow rate MFRof 5 g/10 min or more and a density of 915&#x2013;960 kg/m. The composition is extruded on the substrate as such or by adding 10 wt-% or less, calculated from the total weight of the coating, of high pressure PE-LD by blending into the extrusion composition or by coextrusion.

Process for producing a polyethylene coating on a substrate

The invention relates to a process for the preparation of an olefin polymer comprising at least two polymerization stage in the presence of an olefin polymerization catalyst material, an olefin polymer produced by such process, and the use of such polymers for the production of fibres, pipes, films, moulded products and products for wire and cable applications.

Olefin polymerization process

This invention relates to a process for the preparation of olefin polymers, preferably a multi-stage process, in which hydrogen is used to control the molecular weight of the olefin polymer produced in a continuous reactor, in particular a process wherein a metallocene or other single site catalyst is present in the polymerization reaction mixture, as well as to olefin polymers produced thereby.

Extrusion coating structure in which at least one layer is made of a polymer composition comprising a multimodal ethylene polymer, which contains from 80 to 100% by weight of ethylene repeating u nits and from 0 to 20% by weight of C,-C,alpha-olefin repeating units, has a density of between 0.920 and 0.960 kg/m,, and which is a blend of at least two different ethylene polymers.

Extrusion coating structure

Process for manufacturing LLDPE polymers

The polymerization of certain alpha-olefins in a gas phase involves the problem of agglomeration of the product into particles disadvantageous from the viewpoint of its handling. In the present invention this problem has been solved by means of a new type of process for the homo- or copolymerization of alpha-olefins. In the process the catalyst system is pretreated by contacting and reacting a transition-metal compound which is solid or on a solid carrier with an organoaluminum compound, and possibly an electron donor, in a liquid medium, and by drying the thus formed reaction product to produce a solid catalyst system. The thus pretreated solid and active catalyst system is then fed together with an alpha-olefin in the gaseous state into a gas-phase reactor, and polymerization is carried out by contacting them with each other. By feeding a dry and active catalyst system into the gas-phase reactor, it is possible to avoid the agglomeration of the product which occurs in conventional processes in which an organoaluminum compound and possibly an electron donor are fed in a liquid medium into the reactor.

Process for the gas-phase homo- or copolymerization of alpha-olefin with

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Porvoo, Finland

Hannu Salminen