IPC 2013 : D21H 23/42 : Paper being at least partly surrounded by the material on both sides (D21H 23/34 takes precedence).

IPC2013 > D > D21 > D21H > D21H 23/00 > D21H 23/42[4] > Paper being at least partly surrounded by the material on both sides (D21H 23/34 takes precedence).
D SECTION D — TEXTILES; PAPER.
D21 PAPER-MAKING; PRODUCTION OF CELLULOSE.
D21H PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C, D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR.
D21H 23/00 Processes or apparatus for adding material to the pulp or to the paper (applying liquids or other fluent material to surfaces, in general B05; processes for making continuous lengths of paper D21F 11/00).
D21H 23/42 · · · · Paper being at least partly surrounded by the material on both sides (D21H 23/34 takes precedence).