CPC Subgroup
D21C 9/12 with halogens or halogen-containing compounds (D21C9/16 takes precedence)
Full Title
After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters > Bleaching > with halogens or halogen-containing compounds (D21C9/16 takes precedence)
3 direct subcodes
Child Classifications
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- D21C 9/14 with ClO2 or chlorites
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