| abstract |
A halogen-free varnish includes (A) resin, (B) curing agent, (C) flame inhibitor, (D) accelerator and (E) additives. (A) resin has novolac epoxy resin, DOPO-CNE and DOPO-HQ-CNE. (B) curing agent includes Benzoxazine resin and phenol novolac resin. Glass fabric cloth is dipped into the halogen-free varnish so as to form a prepreg with better thermal stability, anti-flammability, low absorbent ability and higher curing rate. Furthermore, the prepreg has more toughness. |