| 摘要 |
A CABLE-SHEATHING COMPOSITION AND ITS USE AS OUTER SHEATH FOR A POWER CABLE OR A COMMUNICATION CABLE ARE DISCLOSED. THE CABLE-SHEATHING COMPOSITION IS A MULTI-MODAL, PREFERABLY BIMODAL, MIXTURE OF OLEFIN POLYMERS, PREFERABLY ETHYLENE PLASTICS, HAVING A DENSITY OF ABOUT 0.915-0.955 G/CM3 AND A MELT FLOW RATE OF ABOUT 0.1-3.0 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/CM3 AND ABOUT 50-2000 G/10 MIN AND (B) ABOUT 0.88-0.93 G/CM3 AND ABOUT 0.1-0.8 G/10 MIN. PREFERABLY, THE OLEFIN POLYMER MIXTURE HAS BEEN OBTAINED BY COORDINATION-CATALYSED POLYMERISATION OF AT LEAST ONE ALPHA-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 POLYMERISATION OR COPOLYMERISATION OF ETHYLENE IN THE FIRST STAGE AND COPOLYMERISATION OF ETHYLENE WITH BUTENE, 4-METHYL-1-PENTENE, 1-HEXENE OR 1-OCTENE IN THE SECOND STAGE. |
