IPC Subgroup
D21H 21/18 Reinforcing agents
Introduced: January 1990
Last revised: January 2006
Full Title
Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper impregnating or coating material, characterised by its function, form or properties > characterised by function or properties in or on the paper > Reinforcing agents
Classification Context
- Section:
- TEXTILES; PAPER
- Class:
- PAPER-MAKING; PRODUCTION OF CELLULOSE
- Subclass:
- 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
1 direct subcode
Child Classifications
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- D21H 21/2 Wet strength agents
Top Applicants
Top 10 applicants by patent filingsfor class D21, 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