Patent.
A method of hydrating fibers (or something like that) doesn't teach away from a subsequent process -- a user wanting a different composition would simply vary the hydration.
Or something like (or utterly unlike) that.
http://www.cafc.uscourts.gov/sites/default/files/opinions-orders/15-1272.Opinion.1-6-2016.1.PDF
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.