Study On Preparation And Properties Of Isotropic Conductive Adhesive Nanocomposites With High Performance

Thermoset type isotropic conductive adhesive (ICA) comprised of epoxy resin E-51 as the matrix, nanosized and microsized copper particles modified by silane coupling KH550 as conductive fillers, polyamide resin with low molecular weight as curing agent, and some other additives. In this work, we reported creatively a new liquid curing agent, polyamide resin with low molecular weight, which solved some difficult problems during preparation of ICA, such as limit of quantity of conductive fillers. Therefore application of this liquid curing agent will decrease greatly the resistivity of ICA under the condition of keeping enough adhesion strength. The influence of different factors such as curing agent, silane coupling agent, reducer, and conductive filler are discussed on bonding performance and conductivity for conductive adhesive by orthogonal experiment. At the same time, the preparation parameters were optimized for conductive adhesive, and the optimal project of preparation conductive adhesive was obtained. The results showed that optimum conditions of conductive adhesive composed of 65 wt% of nano-and micron copper powder with curing time for 4 hours at 60℃. The adhesion strength reached 17.6 MPa and the bulk resistivity is lower than 3.6×10-4Ω·cm. The change rates of bulk resistivity were less than 10% at high temperature (85℃).In the follow-up study, polyimide prepared conductive composites with thermal stability was tested and analysed for their property. These results supply research directions and theoretical support for the applications of polyimide matrix conductive composites in electronic material field.