Study of Plastic Plating Using Highly Concentrated Ozonized Water Pretreatment

In order to achieve good adhesive properties, typical decorative plastic plating technology uses a chromic acid process that creates an anchor effect. Due to environmental concerns with hexavalent chromium, there is a need to find alternative processes. Pretreatment using highly concentrated ozonized water was investigated as a novel approach to achieving this goal.

In the conventional chromic acid process, strong adhesion between plating membranes is achieved by roughing the ABS (acrylonitrile-butadiene-styrene) resin surface by approximately 1 um. On the other hand, the highly concentrated ozonized water process achieves good adhesion with a smooth resin by changing the resin from ABS to ASA (acrylate-styrene-acrylonitrile). It was discovered that the difference in this strength of adhesion was the difference in resin surface strength (existence of deterioration or otherwise).

In addition, chemical analysis and cross-sectional observations were made after each plastic-plating process in order to elucidate plating adhesion mechanisms on smooth resinous surfaces. Analysis revealed the formation of a polar group on resinous surfaces after highly concentrated ozonized water treatment and property modification in resin surface layers. Moreover, by means of catalytic plating, catalytic particles diffuse and absorb into modified resin surface layers. Metal nanoparticles penetrate and are dispersed in the resin surface layers through the subsequent plating process. The above results showed that adhesion was ensured through the achieving of a nano-scale modified layer that is entirely different to the conventional anchor effect.