Inhibition of Dioxins in Combustion of Printed Wiring Boards by Use of Hydrogenated Alicyclic Epoxy Resin

Abstract

The amount of halogenated dioxins in combustion gases of printed circuit boards depends on the concentration of halogen in the substrate, and also changes with resin structures to be applied. In this study, it was revealed that by combined use of fine aluminum hydroxide, phosphate flame retardant and alicyclic epoxy resin instead of halogenated epoxy resin or aromatic epoxy resin, these printed circuit boards met UL94-V0 flammability classification. Furthermore halogenated dibenzodioxin/dibenzofuran was hardly detected in combustion gases. The printed circuit boards which consisted of alicyclic epoxy resin could control generating of halogenated dioxins, as compared with aromatic resin. According to the heat decomposition behavior, it was suggested that alicyclic resin was easy to decompose because of weak C-C bond strength and generating of halogenated dioxins were controlled by the structure of resins.