Fabrication of Void- and Dicy-Crystal-Free Epoxy Prepreg Using a Modified Fr-4 Epoxy Resin System
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
An epoxy resin solution for coating glass cloth in the fabrication of epoxy prepregs is provided and comprises an epoxy resin and a catalyst mixture. The epoxy resin includes bisphenol A-type epoxy resin, epoxy cresol novolac, and an N-methyl-pyrrolidone solvent. The catalyst mixture includes dicyandiamide, tetramethylbutanediamine and the N- methyl-pyrrolidone solvent. The provided solution substantially eliminates the voids and dicyandiamide crystals which appear in the prepregs of the prior art which tend to contribute to short circuits.