| 摘要 |
A moulding composition comprises an olefinic hydrocarbon polymer, e.g. polyethylene, between 0,25 and 1,5 parts of carbon black per part by weight of the polymer, and minor amounts of an organic cross-linking agent with a perbenzoxy group and a metal oxide selected from zinc, calcium, barium, strontium and magnesium monoxides and aluminium trioxide. The cross-linking agents may be of general formula: <FORM:0873159/IV (a)/1> where R is an alkyl, cycloalkyl or aryl radical or a combination thereof, e.g. t-butyl-, p-menthane and cumyl perbenzoates, and the preferred oxide is magnesium oxide. The composition may be prepared by milling e.g. at 180 DEG to 230 DEG F. and cured on fabrication, e.g. at 350 DEG F. for 10 minutes, to give a tough, flexible, temperature resistant electrical insulator suitable for drop-wire and high frequency applications. |
