If you’re ready to “party like its 1989,” you’ll have to talk to Taylor Swift first. The pop star recently applied to trademark that phrase and others related to her songs — a move that marks a shift in the industry, as artists, songwriters and music publishers increasingly become independent brands. But the case also raises questions about where artists and industry players might cross the line and damage their reputations. Among the other phrases that Swift wants to trademark are “This sick beat,” and “cause we never go out of style,” both of which are lyrics from songs on her 1989 album. If she does secure those rights, it will prevent unauthorized use of those phrases in products including soap, sun care products, cosmetics, fragrances and bleaching preparations, among others. Swift’s trademark quest could work out fine, or it could backfire, according to R. Polk Wagner , a professor at the University of Pennsylvania Law School, whose specialties include copyright and trademark law.…