Synthesis of adhesion promoter for lead frame bonding and application of epoxy composite materials

Abstract Polymer adhesion promoters were formulated to improve the adhesion strength of lead frame/epoxy composites. The poly(itaconic acid‐ co ‐acrylamide) (IAcAAM) was synthesized via free radical polymerization to improve the interfacial adhesion between Ni and Cu lead frames and epoxy composites. IAcAAM was synthesized by setting itaconic acid (IA) and acrylamide (AAM) at molar ratios of 7:3, 5:5, and 3:7. The interfacial adhesion mechanism was investigated by introducing IAcAAM with three different comonomer molar ratios. The adhesion strength between EMC and Cu and Ni substrates to which each IAcAAM was applied was measured using a universal testing machine, and the effect of IAcAAM with various IA:AAM molar ratios on the surface energy of EMC was closely studied. As a result, the adhesion properties of Ni lead frame/epoxy composite and Cu lead frame/epoxy composite were improved as small amounts of all IAcAAM samples were added to the epoxy mixture. We confirmed that IAcAAM with an appropriate molar ratio can be used in the EMC process and has the potential to increase the adhesion of epoxy composites and metal lead frames. Highlights A polymeric adhesive promoter was synthesized to enhance the adhesion strength of lead frame/epoxy composites. Poly(itaconic acid‐co‐acrylamide) (IAcAAM) was copolymerized from itaconic acid and acrylamide for this purpose. The adhesion strength of lead frame/epoxy composites was compared for different IAcAAM monomer contents and with a commercial adhesive promoter. IAcAAM showed superior adhesion strength in the Ni lead frame/epoxy composite material. The highest adhesion strength was achieved at a monomer composition of 5:5.