New Chromium Free Pretreatment Method for Plating on ABS Resin Using TiO2under UV Light Irradiation

Abstract

ABS resin has been widely applied as a plating substrate on plastics in applications such as vehicles and electrical devices. Generally the ABS resin is etched by strong oxidizing agents including H2SO4and CrO3for the improvement of adhesion strength between the deposited metal and the ABS resin. This etching method has been used in production for over 40 years. In recent years, environmental pollution control has become an important concern, as we can see in documents such as the EU Directive on Waste from Electrical and Electronic Equipment (WEEE) and Restriction on Hazardous Substances (RoHS). Surface finishing technologies for corrosion protection in automobiles have become especially urgent matters for cutting down the hazardous substances. As per the EU Directive on the End of Life Vehicles (ELV), the use of hexavalent chromium on automobiles related parts will be forbidden in the European Union area after July, 2007. Accordingly, we are required to develop an alternative technology without using hazardous materials. We have focused on the application of titanium oxide (TiO2), which is a photocatalyst, as an alternative to chromic acid, and have found chemical reforming on the ABS resin surface by UV light irradiation under the presence of TiO2. We confirmed that reforming of the ABS substrate by this process improved the adhesion between electroless Ni-P plating film and ABS. Adhesion strength of about l. Okgf/cm between ABS and deposited metal was obtained under the optimum treatment condition. © 2005, The Japan Institute of Electronics Packaging. All rights reserved.