CPC Subgroup
D21H 17/63 Inorganic compounds
Full Title
Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution > Inorganic compounds
5 direct subcodes
Child Classifications
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- D21H 17/64 Alkaline compounds
- D21H 17/65 Acid compounds
- D21H 17/66 Salts, e.g. alums
- D21H 17/67 Water-insoluble compounds, e.g. fillers, pigments
- D21H 17/70 forming new compounds in situ, e.g. within the pulp or paper, by chemical reaction with other substances added separately
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