| 摘要 |
<p>A flame retardant electrical cable comprises at least one elongate electrical conductor bearing a layer of electrical insulation and encased in a protective jacket which is able to meet or to exceed the flame spread requirements of Underwriters Laboratories Tunnel Flame Test UL 910 as a result of at least one of the conductor insulation or protective sheath being made from a first melt processable, non-fluorocarbon polymer (I) and the other of the conductor insulation or sheath being made from a second melt processable fluorocarbon or non-fluorocarbon polymer (II) which may be the same or different from the first polymer (I). The cable satisfies the condition that the composite Stainer Index of the first and second polymers is less than ca. 3500 according to the formula in which S.I. (steiner Index) = (A) (B) (C) (1-O.I.) where mass = the respective number of pounds of (I) and (II) included in the cable subjected to the UL 910 Flame test; (A) = the respective specific heat of the (I) and (II) in Btu/lb; (B) = the respective specific gravity of (I) and (II); (C) = the respective % by mol. wt. of non-halogenated elements of the (I) and (II) to the respective total mol. wt. of these expressed in decimal form; and O.I. = the respective Limiting Oxygen Index of the (I) and (II) according to ASTM D2863, expressed in decimal form. The cable is devoid of any component disposed as a barrier between the conductor insulation and the jacket having at least a portion made from a polymer having more than ca. 35% by mol. wt. of fluorine to the total mol. wt. of the polymer.</p> |
