D21F PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
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.
Filing statistics
CPC subclass D21F recorded 14,174 patent applications worldwide between 2013 and 2023. Annual filings grew from 937 in 2013 to 950 in 2023 (+1%), peaking at 1,654 applications in 2017. 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
8 direct subcodes
Child Classifications
Navigate with arrow keys, Enter to open
- D21F 1/00 Wet end of machines for making continuous webs of paper
- 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
- 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)
- D21F 2/00 Transferring continuous webs from wet ends to press sections
- D21F 3/00 Press section of machines for making continuous webs of paper
- D21F 5/00 Dryer section of machines for making continuous webs of paper
- D21F 7/00 Other details of machines for making continuous webs of paper
- D21F 9/00 Complete machines for making continuous webs of paper
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