| 摘要 |
<p>A flame retardant thermoplastic elastomeric compsn. contains an elastomeric (I) and non-elastomeric component (II). (I) in moulded form has a durometer hardness of 70 Shore A to 50 Shore D and is made from a blend of 25-75 pts.wt. of crystalline thermoplastic olefin resin and 75-25 pts.wt. of fully vulcanised mono-olefin copolymer rubber derived from ethylene or propylene and alpha-olefin(s) CH2=CHR (where R is 1-12C alkyl) and opt. a minor amt. of a copolymerisable diene. The rubber is vulcanised to provide the blend with a tensile strength at least 60 kg/sq.cm. greater than that of the unvulcanised blend, the rubber also being in the form of small dispersed particles. (II) comprises (a) 20-40 pts.wt. of chlorinated, brominated or chlorobrominated flame retardant(s) per 100 pts.wt. of (I), the cpds. having a halogen content of 50-85 wt.%, (b) 5-20 pts.wt. of Sb oxide per 100 pts.wt. of (I) and (c) 0.01-8 pts.wt. of Pb oxides, -stearate, -fumarate or -phthalate stabilisers or mixt. per 100 pts.wt. (I). The compsn. has ASTM D2863 limiting oxygen index of 24-27% and in the form of an insulating covering about an electrical conductor, the compsn. meets or exceeds the flame test requirements of UL VW-1. In the form of a jacket about an electrical cable, the compsn. meets or exceeds the cable flame test requirements of IEEE-383.</p> |
