IPC Main Group
D21D 1/00 Methods of beating or refining; Beaters of the Hollander type
Introduced: September 1968
Last revised: January 2006
Classification Context
- Section:
- TEXTILES; PAPER
- Class:
- PAPER-MAKING; PRODUCTION OF CELLULOSE
- Subclass:
- TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
Related Keywords
MILL(S) for refining paper-making pulp
2 direct subcodes
Child Classifications
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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