Research materials are physical items that are generally either purchased by the University or manufactured from materials that were purchased by the University. The items themselves are owned by the University. A researcher could not, for example, take cell lines or microscopes that the PI created, sell them, and put the money in her pocket. The PI could, of course, write about the process of creating them, and would own copyright in the written material. (And, if the materials are patentable, the Patent Policy would apply to the underlying invention).
Research data are “the recorded factual information associated with the research” collected or generated in the course of the research, and which may be physical or digital. Research data “necessary for the reconstruction and evaluation of the results of research” are subject to this policy.