Hi there! Sorry it took a while to get back to you.

An emotion resistant armour is feasible to make, yes! It may require a ton of testing and experimenting and failures (which in turn may lead to various emotional effects), but it can definitely be made. As for what materials may be used for it, Trunks will have to do some island hopping. There are some smaller floating islands that can be accessed via airships. Perhaps the one that's almost dead due to all the lack of emotion and inhabitants may help him...