Electroplating on PP/ Plastics

A. Some olefins can be plated but the end product may not be very good. This can be achieved by either using a co-polymer or by special surface activation by plasma etching. Conventional chromic acid etching does not appear to be very good on olefinic monopolymers. The problem with PP is that it has a very low SG (less than 1 so it floats in water) and it has a high coefficient of thermal expansion. Combined with its reluctance to produce a chemically active surface, any metal coating has major adhesion problems, especially if the product is to be thermally cycled.

? I am no expert on plating-on-plastics, Trevor, and I do recognize that ABS is the predominant substrate. But am I wrong in believing that decorative plating-on-plastics started on polypropylene? I seem to recall programming large automated plating lines where they ran polypro parts through electroless copper and ABS parts through electroless nickel (or vice versa) after activation and sensitizing.

A. Ted,

I cannot answer your point about the origins of POP, as I was not aware of your point! My only comment is I have always found it very difficult to get a good adherent coating onto it. I would be very interested in knowing how the polypro was activated and sensitised in those days. Sorry I cannot shed any more light on your thoughts!

 Thanks, Trevor. We'll have to wait for some oldtimer to either confirm this dim memory of mine or refute it. It was a very long time ago when I was only into the programming of plating machines and not the process chemistry, and my recollection was that the line handled both PP and ABS, and all work went through the conventional chromic-sulfuric etch and sensitization and activation first. It could be an erroneous memory though :-)

A. Hi Sameer. Automotive quality plating on plastic, which requires outstanding adhesion, would probably be beyond your budget and convenient resources.

But a more generalized plating on plastic or organic materials sounds quite doable. Please see our FAQ, "Plating Organic Materials". Good luck.

Regards,

A. Hi Kacper. You can try 'plating polypropylene' at surfacequery.com and see if anything comes up. Most of the papers published in finishing journals are indexed there. Good luck.

Regards,