Patents for paper deacidification

The brittle-paper problem, i.e. the acid-catalyzed decay of cellulose originating from the invention of alum-rosin sizing at the beginning and of wood as a raw material for papermaking in the middle of the 19(th) century, has challenged chemists and technicians to search for remedies. Since the beginning of relevant research in the first half of the last century more than 70 patents have been issued. After a highlight in the early and a certain drop in the late 90s a new rise is observed in the first years of the new century, concentrating on safer and more environmentally friendly chemicals and procedures.