IPC 2013 : D21J 3/02 : of rings.IPC2013 > D > D21 > D21J > D21J 3/00 > D21J 3/02 > of rings.
D SECTION D — TEXTILES; PAPER.
D21 PAPER-MAKING; PRODUCTION OF CELLULOSE.
D21J FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MÂCHÉ (manufacture of articles by dry processes B27N).
D21J 3/00 Manufacture of articles by pressing wet fibre pulp, or papier-mâché, between moulds.
D21J 3/02 · of rings.