LOW-LOSS FOAM COMPOSITION WITH AND LOW-LOSS FOAM-LAYERED CABLE

摘要

FIELD: chemistry.;SUBSTANCE: invention refers to foam composition for cables and to telecommunications cable containing foam composition. Foam composition of density 85 kg/m³ to 120 kg/m³ is produced by heating up the olefin polymer, mainly, with foaming initiator added to molten state. Molten mixture is extruded under pressure through draw plate using foaming agent containing atmospheric gas, e.g. carbon dioxide, nitrogen or air, and additional foam-blowing agent of boiling point within -65°C to +50°C, selected from hydrofluorocarbons, hydrochlorofluorocarbons or perfluoro compounds. As olefin polymer mixture contains high density polyethylene, average density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene or their combinations. Cable is produced by extruding foam composition to signal-carrying conductor and coating signal-carring conductor embedded in foam material with suitable conducting screen.;EFFECT: produce telecommunication cable of low-loss signal; mixture of foaming agents is ecologically comprehensible, not inflammable and nontoxic and allows for considerable reduction of foam density maintaining number of open pores at comprehensible level.;15 cl, 9 tbl, 16 ex