D21 PAPER-MAKING; PRODUCTION OF CELLULOSE
Classification Context
- Section:
- TEXTILES; PAPER
- Class:
- 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.
Related Keywords
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
- D21H PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES ,; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS OR SUBCLASS; PAPER NOT OTHERWISE PROVIDED FOR
- D21J FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MÂCHÉ
Top Applicants
Top 10 applicants by patent filings, 2013–2023, worldwide · Source: EPO PATSTAT
- VOITH PATENT DE 1,809
- STORA ENSO FI 1,467
- KEMIRA FI 1,086
- KIMBERLY-CLARK CORPORATION US 935
- VALMET TECHNOLOGIES FI 924
- VALMET SE 904
- P&G (PROCTER & GAMBLE COMPANY) US 862
- OJI HOLDINGS CORPORATION 696
- OMYA INTERNATIONAL CH 584
- SOUTH CHINA UNIVERSITY OF TECHNOLOGY 571