StudyonAnti-tracking Properties ofUnsaturated Polyester ResinSMC

A method of thickening hydroxyl-terminated unsaturated polyester with polyurethane (PU)thatcomesfromthereaction between diisocyanate compounds andpolyglycol is introduced, andtheeffect ofPUprepolymer onthe anti-arc properties ofthesheet molding compounds (SMC)isstudied according tothestandard ofASTM, theelectric strength istested inthetransformer oil under423K,453K,473K,523Krespectively. The anti-tracking properties ofUP-SMCweredeveloped whenAl(OH)3 anddiisocyanate compounds were filled inUP-SMC.Themicrostructure ofUP-SMC struck byelectric arcwasobserved bymeansofSEM (Scanning Electron Microscopy). Theresults show thatUP-SMC samples withno anti-tracking modification havesomepart ofablation andcharring while themodified sample arewiththelowelectric rot. Thearcbreakdown timewouldincrease withthe usage ofPU.TheSMCthickened byPUshowsgood aging resistance aswellasanti-arc properties, itwill bewidely usedonelectrical parts andarc-deflecting cover ofAC switch etc.