| abstract |
A transmission line, constituted for example by an electric wire or by an optical fiber, comprises a layer of insulation or sheathing material which is formed from a composition comprising: (a) a polyamide-based polymer, polyester, polyphenylene oxide, silicone or alkene-vinyl acetate; and (b) from 10 to 30% by weight, calculated on the basis of the total weight of the composition, of magnesium hydroxide, which has an effective surface A and a weight average particle size S such that the ratio between them (A / S) is at least 8 x 109 mkg-1. By choosing magnesium hydroxide, it has been discovered that a better reduction in the emission of smoke in electrical insulation or sheathing materials based on the polymers described above is obtained in the event of a fire. compared to other polymers. |