STUDIES ON ADHESION OF ALLYLIC RESIN .I. ADHESION OF DIALLYLPHTHALATE RESIN AND DICHROMATE-TREATED COPPER FOIL

An effective copper surface treatment for adhesive bonding of copper foil and diallylphthalate resin was investigated. It involves dipping the copper foil in the potassium dichromate‐sulfuric acid solution (K2Cr2O7:76 g/l, H2SO4:0.67 N) at 60°C for 5 min. The dichromate treated copper foil and glass based prepregs of diallylphthalate resin were laminated under the pressure of 38 kg/cm2 for 30 min at 145°C. Interface characteristics of the dichromate treated copper foil and diallylphthalate resin were examined. It was found that chromium is formed on the surfaces of the treated copper foil, and allyl groups in diallylphthalate molecule are oriented to the atoms, that is, the adhesive bonding is performed by the chemical affinity of chromium and allyl groups. The allyl group has a delocalized π‐electron system, and that its bonding to a transition metal as chromium is appropriate and justifiable by quantum chemical considerations. Copyright © 1969 John Wiley & Sons, Inc.