Fabrication of h-BN Filled Epoxy-Based Thermally Conductive Adhesive Tapes Containing Cyclic Carbonate-Terminated Oligomers

Thermally conductive (TC) adhesive tapes consisting of adhesives and TC fillers are widely used as thermal interface materials because of their tack properties for temporary fixation and high peel strength for permanent bond. However, the trade-off between peel strength and thermal conductivity with increasing filler loading impedes the manufacture of high-performance TC tapes. Therefore, a technique to realize high thermal conductivity of TC adhesives with lower filler loading is crucial. In this study, epoxy-based adhesives (EAs) was used to fabricate TC adhesive tapes. To secure high peel strength of EAs, a cyclic carbonate-terminated oligomer (CCO) was synthesized and employed as a component. The simultaneous reactions between epoxy resin, CCO and curing agent were analyzed using FTIR spectroscopy. Thanks to tack, the partially cured EAs could be used to fabricate tapes which were temporarily fixed and then permanently bonded via complete curing. Next, EAs and h-BN fillers were admixed to produce TC adhesive tapes. Because h-BN fillers were partially aligned to the in-plane direction by bar-coating, the in-plane thermal conductivity of the TC-1 adhesive containing only 20 wt% h-BN fillers was as high as 2.73 W/m K, which was slightly lower than that (2.97 W/m⋅K) of the TC-4 adhesive containing 35 wt% h-BN fillers. In addition, the peel strength of the TC-1 adhesive tape reached 2307 (± 64) gf/in.