Preparation and performance of epoxy resin conductive adhesive with fast-curing feature at low temperature

A thermoset type isotropic conductive adhesive (ICA) was prepared by epoxy resin E-51 as the matrix, nanosized and microsized copper powder modified by silane coupling KH550 as the conductive fillers, polyamide resin with low molecular weight as the curing agent, and some other additives. A new liquid curing agent, polyamide resin with low molecular weight, was used which solved some difficult problems during the preparation of ICA, such as limit of quantity of conductive fillers. The effects of different factors such as curing agent, silane coupling agent, reducer, and conductive filler on the bonding performance and the conductivity for conductive adhesive were discussed by the orthogonal experiments. The preparation parameters of the conductive adhesive were optimized, and the optimal preparation parameters for the conductive adhesive was obtained. The results show that optimum conditions of conductive adhesive are composed of 65% of nano-and micro-copper powder with curing time for 4 hours at 60 ℃. The adhesion strength reaches 17.6 MPa and the bulk resistivity is 3.6×10^-4 Ω·cm. The change rates of bulk resistivity are less than 10% at the high temperature (85 ℃) and the high humidity(RH 85%).