| 摘要 |
PCT No. PCT/GB97/00463 Sec. 371 Date Aug. 31, 1998 Sec. 102(e) Date Aug. 31, 1998 PCT Filed Feb. 20, 1997 PCT Pub. No. WO97/31975 PCT Pub. Date Sep. 4, 1997A 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 10-45, preferably 10-34, micrometers are advantageous in resisting pressures up to 50 MPa (5 km under sea).
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