Improving bonding of EMC to LF metals with melamine-phenol-formaldehyde resins

MPF resoles were synthesized with ammonia catalyst. The nitrogen content of the synthesized MPF resins was measured with Elemetar analyzer and the molecular structure was analyzed with FTIR. The effect of the MPF resoles as primer on the bonding of EMC to Cu, Ni, Ag, Pd or Au was investigated. The melamine moiety as well as the amine catalyst joined to the resoles, leading to higher nitrogen contents than the theoretical values based on the charging ratio of monomers. The introduced nitrogen gave remarkable contribution to the PF resole in adhesion promotion between EMC and LF metals. When the MPF resoles were applied on copper surface as primer, the shear strength increased with increasing nitrogen content till 12 %. Beyond this point the shear strength left off as the nitrogen content increased further. The shear strength would vary also as the concentration of the resole solutions changed. However, within the range from 0.4 % to 10 %, the shear strength could remain at levels above 6 MPa. Even under MSL I condition, the bonding of EMC to LF metals could be enhanced more than two times.