D TEXTILES; PAPER
D21 PAPER-MAKING; PRODUCTION OF CELLULOSE
D21H PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
D21H17/00 Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
D21H17/03 Non-macromolecular organic compounds
D21H17/05 containing elements other than carbon and hydrogen only
D21H17/07 Nitrogen-containing compounds