Session Details
Session 7: Decorative Automotive Considerations
Abstract Number:
31
CBM, Covalent Bonded Metallization, a chemical surface modification on a molecular level. Adhesion promotion that allows for metal plating on a multitude of polymers (incl. non-plating grade) without the use of hexavalent chromium. This technology also increases the number of platable polymers and furthermore it is more forgiving to injection molding parameters. CBM is also possible technique to use within the PCB industry, especially for production of high frequency electronic, both PCBs and antennas.
Topics:
Advances & New Trends in Surface Finishes/Engineering
Advances in Surface Finishing Technology
CBM, Covalent Bonded Metallization. This emerging technology allows for metallization of polymeric surfaces. Same process for e.g. PCB, POP, Automotive and Sanitary. It is an adhesion promotion technology that after treatment of the pure plastics enables the usage of conventional plating chemistry. However, for the POP industry it also removes the need for pre etching with hexavalent chromium. Plastic surfaces in general are hydrophobic and not particularly susceptible to electrochemical deposition of metals. To overcome these disadvantageous properties the plastic substrate needs to be pretreated. Current techniques utilize etching with metal salts, acids and heat to deteriorate the chemical structure of the surface layer in the plastic. The CBM technology described here achieve hydrophilicity and electrochemical environment, but in an additive manner. Parts are coated with a monomer solution followed by exposure to an energy source. This results in creation/alteration of the molecules on the surface of the plastic. This method is referred to as "grafting" and the added molecules as "graft polymers". The graft polymers have hydrophilic properties, as well as electrochemical properties suitable for metal deposition. The solution is an engineered chemistry with initiators and catalysts that minimize the energy required for the modification of the surface. Following the CBM process, normal Palladium catalysts for electroless metal deposition might be used, but also Silver catalysts have been showed to work well with this system. The CBM allows for a multitude of polymers, including non-plating grade, to be used, i.e., it enables the selection of polymers for desired product properties instead of plating ability. Furthermore, the injection molding parameters are not as crucial when plating with the CBM process. Regarding PCB industry, the surface structure is somewhat irrelevant for the CBM process, it allows for very smooth substrate surface which with increasing frequency becomes more important.