D21 PAPER-MAKING; PRODUCTION OF CELLULOSE
Description
This class encompasses the industrial production and processing of paper and cellulose materials, including pulping processes, bleaching, and paper manufacturing techniques. It covers machinery, methods, and apparatus used throughout the paper production chain, from raw material preparation through final paper formation and finishing. The classification includes technologies for producing various paper grades, cellulose derivatives, and related fibrous materials used in industrial and consumer applications. Adjacent classes address textile fiber production (D01) and subsequent paper converting or finishing operations not integral to the core paper-making process itself.
Filing statistics
CPC D21 recorded 101,884 patent applications worldwide between 2013 and 2023, summed across its 7 subclasses. Annual filings declined from 7,573 in 2013 to 7,216 in 2023 (-5%), peaking at 11,293 applications in 2018. The most active applicants in class D21 are VOITH PATENT (1,857 applications), STORA ENSO (1,552 applications) and KEMIRA (1,173 applications).
Source: EPO PATSTAT, worldwide filings
7 direct subcodes
Child Classifications
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- D21B FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- D21C PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21D TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
- D21F PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21G CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES (winders or rewinders for finished products, means for adjustment of wrinkles or lateral extensions B65H)
- 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
- D21J FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE (manufacture of articles by dry processes B27N)
Top Applicants
Top 10 applicants by patent filings, 2013–2023, worldwide · Source: EPO PATSTAT
- VOITH PATENT DE 1,857
- STORA ENSO FI 1,552
- KEMIRA FI 1,173
- KIMBERLY-CLARK CORPORATION US 1,107
- VALMET TECHNOLOGIES FI 965
- VALMET SE 943
- P&G (PROCTER & GAMBLE COMPANY) US 941
- OMYA INTERNATIONAL CH 821
- UPM-KYMMENE CORPORATION FI 512
- SEIKO EPSON CORPORATION JP 501