A new one-component electrically conductive adhesive with excellent electrical conductivity and mechanical properties using tetra-functional polyurethane acrylate oligomers and silver particle fillers

Electrically conductive adhesives (ECAs) are mainly used in integrated circuit (IC) packaging, light-emitting diode (LED) packaging and other electronic industries to replace traditional solders and lead-free solders. The electrical conductivity and mechanical properties are contradictory with an increase in the content of conductive fillers. Therefore, there is a continuous need to improve electrical conductivity without serious damage to the mechanical properties of ECAs. In this work, a tetra-functional polyurethane acrylate oligomer was used as the main composition of silver filled one-component ECAs to improve performance. By introducing the tetra-functional oligomer, low volume resistivity with good adhesion characteristics was achieved. The volume resistivity and lap shear strength of the silver flake filled ECAs were studied systematically. The ECA with 30.6 vol% content of silver flakes exhibits low volume resistivity of 1.02 × 10−7 Ω m, with a lap shear strength of 8.995 MPa.