CPC Main Group
D21H 25/00 After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
Filing statistics
CPC D21H 25/00 belongs to the parent subclass D21H, which recorded 50,846 patent applications worldwide between 2013 and 2023. Annual filings declined from 3,964 in 2013 to 3,670 in 2023 (-7%), peaking at 5,497 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
5 direct subcodes
Child Classifications
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- D21H 25/02 Chemical or biochemical treatment (D21H25/18 takes precedence)
- D21H 25/04 Physical treatment, e.g. heating, irradiating (D21H25/18 takes precedence; dryer section of machines for making continuous webs of paper D21F5/00)
- D21H 25/08 Rearranging applied substances, e.g. metering, smoothing; Removing excess material
- D21H 25/18 of old paper as in books, documents, e.g. restoring
Top Applicants
Top 10 applicants by patent filingsfor class D21, 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