Kinsella’s recent interview had a part on this (with a few resources as well), and it reminded me of this thread. Here ya go:
Daily Bell: You provide non-utilitarian arguments for intellectual property being incompatible with libertarian property rights principles. Can you explain this?
Stephan Kinsella: I alluded to this above in my discussion about negative servitudes. An IP right gives the holder the right to stop others from using their property as they wish. For example, George Lucas, courtesy copyright law, can use the force of state courts to stop me from writing and publishing “The Continuing Adventures of Han Solo.” J.D. Salinger’s estate was able to block the publication of a sequel to Catcher in the Rye, for example. This is censorship. (See The Patent, Copyright, Trademark, and Trade Secret Horror Files.) And Apple can get a court order blocking Samsung from selling a tablet if it resembles an iPad too closely. This is just protection from competition. (See Intellectual Property Advocates Hate Competition.)