Q: I have a problem with a functional powder coating we use to electrically insulate electric motor armatures. It’s a Bis A/ECN (bisphenol A/epoxy cresol novolac) resin system, calcium carbonate filled and Dicy (dicyandiamide) cured.
When the cure temperature gets above about 210°C, there is an odor given off that a customer is complaining about. What odor maskers or absorbers might help us out of this one?
A: You may have three or four approaches:
1. Identifying and eliminating the source of the odor. This would involve a compositional change, but it may be as simple as comparing different grades and suppliers of the ECN resin.
2. Consuming the odor-causing species. It probably involves volatile, low-molecular-weight fragments, and it may be possible to react or adsorb these compounds to render them less or non-volatile.
3. Masking. This would involve introducing a fragrant compound that would overwhelm the odor caused by the formula. It would be important to find something that would perform at the relatively high temperature.
4. Bonus approach: Replacing the current product with a lower-temperature-cure formula might minimize the evolution of odor.