Borealis Polymers Oy

Borealis Technology Oy

Nk Cables Oy

Hans-Bertil Martinsson

Laila Rogestedt

Ruth Dammert

Markku Asumalahti

Leif Leiden

Jari Aarila

Aimo Sahila

Vesa Tuunanen

Jari Aaril&auml;

Tarja Korvenoja

Eeva-Leena Heino

Lars Thorn

Bengt Hagstrom

The present invention is concerned with an optical cable with improved tracking resistance comprising at least one optical fiber and an outer sheath which comprises a polymeric material, characterized in that the polymeric material forms a matrix for the sheath and consists of a multimodal olefin polymer obtained by a coordination catalyzed polymerization, and in that the total composition of the sheath comprises 15&#x2013;40% by weight of a metal hydroxide, preferably magnesium hydroxide and/or aluminium hydroxide, and 0.01&#x2013;0.9% by weight of carbon black.

Optical cable with improved tracking resistance

Conventional coating compositions have the disadvantage of being insufficiently coatable and having an unsatisfactory environmental stress cracking resistance. Now a coating composition has been found which has both good coating processability and environmental stress cracking resistance. It comprises a multimodal ethylene polymer, which contains from 80 to 100% by weight of ethylene repeating units and from 0 to 20% by weight of C -C &agr;-olefin repeating units, has a density of between 0.915 g/cm and 0.955 g/cm , and is a blend of at least a first ethylene polymer having a first average molecular weight and a first molecular weight distribution and a second ethylene polymer having a second average molecular weight, which is higher than said first average molecular weight, and a second molecular weight distribution, said blend having a third average molecular weight and a third molecular weight distribution.

Coating composition

A cable-sheating composition and its use as outer sheath for a power cable or a communication cable are disclosed. The cable-sheating composition is a multimodal, preferably bimodal, mixture of olefin polymers, preferable ethylene plastics, having a density of about 0.915-0.955 g/cm,and a melt flow rate of about 0.1-0.3 g/10 min, said olefin polymer mixture comprising at least a first and a second olefin polymer, of which the first has a density and a melt flow rate selected from (a) about 0.930-0.975 g/cm,and about 50-2000 g/10 min and (b) about 0.88-0.93 g/cm,and about 0.1-0.8 g/10 min. Preferably, the olefin polymer mixture has been obtained by coordination-catalyzed polymerization of at least one &agr;-olefin in several stages, preferably two stages consisting of a loop reactor/a gas-phase reactor or a gas-phase reactor/a gas-phase reactor, through polymerization or copolymerization of ethylene in the first stage and copolymerization of ethylene with butene, 4-methyl-1-pentene, 1-hexene or 1-octene in the second stage.

Cable and method for using a cable-sheathing composition including an ethylene polymer mixture

A multimodal polymer composition for fiber optical cables and a fiber optical cable comprising the composition are disclosed. The composition is characterized in that it comprises a multimodal polyethylene with a density of 0.920-0.965 g/cm,and a viscosity at a shear stress of 2.7 kPa (&eegr;,) of at least 150 kPa.s, said multimodal polyethylene comprising a low molecular weight (LMW) ethylene homo- or copolymer fraction and a high molecular weight (HMW) ethylene copolymer fraction, said multimodal polymer composition having a weight ratio of the LMW fraction to the HMW fraction of (35-55):(65-45). Preferably, the multimodal polyethylene is a bimodal polyethylene and has 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;20-150. Also, preferably, the multimodal polyethylene has a MFR,of 0.1-2.0 g/10 min and a melt strength at 190&deg; C. of at least 4 g. The multimodal polymer composition is particularly useful as a material for slotted core elements of fiber optical cables of the slotted core type.

Multimodal polymer composition

An insulating composition for communication cables (,) is disclosed as well as a telesingle wire (,) which comprises the insulating composition and a telecommunication cable (,) which comprises a plurality of telesingle wires (,) including the insulating composition. The insulating composition comprises a multimodal olefin polymer mixture, obtained by polymerization of at least one &agr;-olefin in more than one stage having a density of about 0.920-0.965 g/cm,, a melt flow rate (MFR,) of about 0.2-5 g/10 min, an FRR,&gE;60, and an environmental stress cracking resistance (ESCR) according to ASTM D 1693 A/10% Igepal, of at least 500 hrs, said olefin polymer mixture comprising at least a first and a second olefin polymer, of which the first is selected from (a) a low molecular weight (MW) olefin polymer with a density of about 0.925-0.975 g/cm,and a melt flow rate (MFR,) of about 300-20 000 g/10 min, and (b) a high molecular weight (MW) olefin polymer with a density of about 0.880-0.950 g/cm,and a melt flow rate (MFR,) of about 0.5-20 g/10 min.

Insulating composition for communication cables

Coaxial high-frequency cable and dielectric material thereof

Growing community of inventors

Varekil, Sweden

Hans-Bertil Martinsson