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Fabrication of Void- and Dicy-Crystal-Free Epoxy Prepreg Using a Modified Fr-4 Epoxy Resin System

IP.com Disclosure Number: IPCOM000039062D
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Cibulsky, M: AUTHOR [+6]

Abstract

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.

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Fabrication of Void- and Dicy-Crystal-Free Epoxy Prepreg Using a Modified Fr-4 Epoxy Resin System

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. Typical epoxy prepreg fabrication processes provide for the coating of an epoxy resin system onto a glass cloth, followed by the heating of the impregnated cloth in a heat treater with multiple heating zones having temperatures as high as 150 degrees Centigrade, for forming the partially cured prepreg. In such a fabrication process it is desirable to provide a prepreg without voids between the glass filaments. The hereinafter described epoxy resin solution including a resin and a catalyst has been found to provide such a prepreg with 280 glass cloth. The preferred epoxy resin includes the following ingredients in their listed proportions: 90.0 parts bisphenol A-type epoxy resin 10.0 parts epoxy cresol novolac

42.0 parts N-methyl-pyrrolidone The preferred catalyst mixture includes the following ingredients in their listed proportio...