D21F PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
Introduced: September 1968
Description
D21F covers machines and methods for manufacturing paper from cellulose pulp, encompassing the complete papermaking process from pulp preparation through final product formation. This includes wet-end machinery (forming sections, pressing units, dryers), size presses, coating and calendering equipment, and associated control systems. The classification addresses both the mechanical equipment and operational methods for producing various paper grades and qualities on industrial paper machines.
IPC and CPC are identically structured here. All 8 subcodes exist in both systems.
2 shared codes have differing titles between IPC and CPC.
Child Classifications
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- D21F 1/00 Wet end of machines for making continuous webs of paper +4 CPC IPC+CPC Available in IPC and CPC
- D21F 11/00 Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines +4 CPC IPC+CPC Available in IPC and CPC
- D21F 13/00 Making discontinuous sheets of paper, pulpboard or cardboard, or of wet web, for fibreboard production (making discontinuous sheets of board in moulds D21J; drying paper, pulpboard, or cardboard, in discontinuous sheet form F26B) IPC+CPC Available in IPC and CPC
- D21F 2/00 Transferring continuous webs from wet ends to press sections IPC+CPC Available in IPC and CPC
- D21F 3/00 Press section of machines for making continuous webs of paper IPC+CPC Available in IPC and CPC
- D21F 5/00 Dryer section of machines for making continuous webs of paper +6 CPC IPC+CPC Available in IPC and CPC
- D21F 7/00 Other details of machines for making continuous webs of paper +5 CPC IPC+CPC Available in IPC and CPC
- D21F 9/00 Complete machines for making continuous webs of paper +1 CPC IPC+CPC Available in IPC and CPC
Top Applicants
Top Applicants (IPC)
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
Top Applicants (CPC)
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