Non-electrically tracking compsn. as outer jacket for cable - comprising highly-filled polyolefin of high softening pt. contg. small proportion of metal hydroxide

摘要

Compsns. (I), which are non-self extinguishing, contain (A) large proportion of polyolefin with high softening pt. (B) large proportion of filler, and (C) small proportion of metal hydroxide. Pref. (A) is high density polyethylene or is polypropylene. (B) is chalk. (C) comprises at most 20%, esp. about 16%. (I) comprises 16-25% (A); 3-8% EVA, EEA, EBA; 45-64% chalk; 10-20% metal hyroxide; 1.6-3.2% C black concentrate (50 kg, sic); and 0.15-1.0% anti-ageing agent(s). Partic. (I) comprises 19.2% HPDE (sic, HDPE, high density polyethylene), 6.4% EVA VAC max. 40%), 6.4% EPDM, 16% Mg(OH)2, 48.1% chalk, 0.7% antiageing agent, and 3.2% C black concentrate (50%). USE/ADVANTAGE - In electric fields of high field strength, e.g., where overhead lines and cables are led together, partic. (claimed) as outer jacket for optical air cables. (I) contain only small proportion of (C) and so are not self-extinguishing but have good nontracking properties, are readily processed, have good shape-stability on mechanical loading, and are shape-stable at up to 60 deg.C.