Borealis Technology Oy

Arja Lehtinen

Kalle Kallio

Merete Skar

Annika Smedberg

Hilkka R Knuuttila

Bill Gustafsson

Jarmo Lindroos

Solveig Johansson

Harri Hokkanen

Ole Jan Myhre

Jari Aarila

Hannu Salminen

Jari Äärilä

Marja Ora

Jussi Laurell

Martti Vähälä

Eija Lappi

Elisabeth Ribarits

Esa Kinnunen

Mats B&auml;ckman

Eeva-Leena Heino

Teija Sihvonen

Jari Aaril&auml;

Anneli Malmberg

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

A process for the preparation of a heat sealable film comprising a core layer and a sealing layer, said process comprising attaching said core layer to said sealing layer, said sealing layer comprising an ethylene copolymer composition in which: (1) there are two distinct maxima in the TREF fractogram of the ethylene copolymer composition; (2) at lest 10%, of the ethylene copolymer composition elutes in TREF at a temperature of less than 50&#xb0; C.; (3) at least 25%, of the ethylene copolymer composition elutes in TREF at a temperature of higher than 75&#xb0; C.; (4) none of the ethylene copolymer composition elutes in TREF at a temperature of higher than 100&#xb0; C.; (5) the ethylene copolymer composition comprises two components, one of which is of relatively high comonomer content and high molecular weight, the other of which is of relatively low comonomer content and low molecular weight, both components being prepared by polymerisation of ethylene with a Calpha-olefin in the present of a single site catalyst; (6) the ethylene copolymer composition has a density of between 905 and 930 kg/m, and an MFRbetween 0.3 and 4.0 g/10 min.

Heat sealable polyethylene film and method for its preparation

An insulating composition for an electric power cable, and an electric power cable that includes a conductor surrounded by an inner semiconducting layer, an insulating layer, and an outer semiconducting layer, where the insulating layer consists of said insulating composition. The insulating composition is characterized in that the ethylene polymer is a multimodal ethylene copolymer obtained by coordination catalyzed polymerization of ethylene and at least one other alpha-olefin in at least one stage, said multimodal ethylene copolymer having a density of 0.890-0.940 g/cm , a MFR of 0.1-10 g/10 min, a MWD of 3.5-8, a melting temperature of at most 125&deg; C., and a comonomer distribution as measured by TREF, such that the fraction of copolymer eluted at a temperature higher than 90&deg; C. does not exceed 10% by weight, and the multimodal ethylene copolymer includes an ethylene copolymer fraction selected from (a) a low molecular weight ethylene copolymer having a density of 0.900-0.950 g/cm and a MFR of 25-500 g/10 min, and (b) a high molecular weight ethylene copolymer having a density of 0.870-0.940 g/cm and a MFR of 0.01-3 g/10 min.

Insulation composition for an electric power cable

This invention concerns process for producing polyethylene compositions, films prepared thereof and process for the preparation of the films. The process comprises subjecting ethylene, optionally hydrogen and comonomers to polymerization or copolymerization reactions in a multistage polymerization. At least one polymerization stage is conducted essentially in the absence of hydrogen. The polymerization reactions are carried out in the presence of a single-site catalyst capable of forming a composition comprising a low molecular weight component with MFR of at least 10 g/10 min and a density higher than the density of the composition and a high molecular weight component. The melt flow rate of the composition is in the range MFR &equals;0.1-5.0 g/10 min and the density of the composition is 915-960 kg/m . The invention makes it possible to produce polyethylene compositions for manufacturing films with a good balance between optical and mechanical properties.

Polymer composition, a process for the production thereof and films prepared thereof

A multimodal polymer composition for pipes is disclosed as well as a pipes made thereof. The polymer is a multimodal polyethylene with a density of 0.930-0.965 g/cm , and a viscosity at a shear stress of 747 Pa of at least 650 Pa.s, said multimodal polyethylene comprising a low molecular weight (LMW) ethylene homopolymer fraction and a high molecular weight (HMW) ethylene copolymer fraction, said HMW fraction having a weight ratio of the LMW fraction to the HMW fraction of (35-55):(65-45). Preferably, the multimodal polyethylene has a viscosity at a shear stress of 2.7 kPa of 260-450 kPa.s; and a shear thinning index (SHI) defined as the ratio of the viscosities at shear stresses of 2.7 and 210 kPa, respectively, of SHI &equals;50-150, and a storage modulus (G&prime;) at a loss modulus (G&Prime;) of 5 kPa, of G&prime; &gE;3000 Pa. The pipe is made of the multimodal polymer composition and withstands a stress of 8.0 MPa gauge during 50 years at 20&deg; C. (MRS8.0). Preferably, the pipe has a rapid crack propagation (RCP) S4-value, determined according to ISO 13477:1997(E), of &minus;5&deg; C. or lower and a slow crack propagation resistance, determined according to ISO 13479:1997, of at least 500 hrs at 4.6 MPa/80&deg; C. The polymer composition affords good non-sagging properties to pipe made thereof.

Polymer composition for pipes

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Helsinki, Finland

Arja Lehtinen