A selfish person does not see any reason to help others; they receive no emotional benefit from doing so.

Call it selfishness or egoism, or whatever else you'd like to call it, but I'd say helping others because it makes you feel good is selfish or egoist, if we are looking for another word.

Are you suggesting that a "union of egoists" may in fact help others, due to the emotional benefits associated with doing so? If that is the case, then I fail to see what distinguishes a "union of egoists" from any other union, save the philosophical emphasis on the self.

Most unions exist (from what I know) in a very bureaucratic manner with elected delegates or consensus direct democracy where individuals have to sacrifice their desires to meet the needs of a "greater good." All involved have to do this, so that the outcome is something that no one is really passionate about.

Stirner's "the union of egoists" is all about free associations of affinity groups. No bureaucratic system like say.. the IWW. A union of egoists isn't a formal union. I'm against formal unions because I believe its primary concern is the continuation of its own existence and not the members of it.