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.‎

MOLECULAR SURFACE ALTERATION TO ALLOW FOR PLATING ON PLASTICS

Björn Atthoff

CTO

Cuptronic Technology AB