| 摘要 |
A low-density polymer composition and use thereof in undersea flotation cables and the like, the composition comprising by volume based on the whole composition, (a) at least 30 % of a polymer component consisting of (i) thermoplastic polyolefin elastomer of room temperature density less than 0.9 g/cc and/or (ii) thermoplastic olefin/(ester or acid) copolymer elastomer, and (b) at least 30 % of micro-balls of room temperature density less than 0.6 g/cc, at least 80 %, preferably at least 90 %, more preferably at least 95 %, by weight, of the micro-balls having a maximum dimension less than 300 .mu.m, preferably less than 200 .mu.m. Preferred elastomers are metallocene-catalysed olefin copolymers of density 0.86-0.88 g/cc, and micro-balls of diameters 1045, preferably 10-34, micrometers are advantageous in resisting pressures up to 50 MPa (5 km under sea).
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