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DIFF Subgroup
D21H 23/70

Multistep processes; Apparatus for adding one or several substances in portions or in various ways to the paper, not covered by another single group of this main group

Introduced: January 1990

Full Title

Full titles differ between systems:

IPC:

Processes or apparatus for adding material to the pulp or to the paper > characterised by the manner in which substances are added > Addition to the formed paper > Multistep processes; Apparatus for adding one or several substances in portions or in various ways to the paper, not covered by another single group of this main group

CPC:

Processes or apparatus for adding material to the pulp or to the paper (applying liquids or other fluent material to surfaces, in general B05; processes for making continuous lengths of paper D21F11/00) > characterised by the manner in which substances are added > Addition to the formed paper > Multistep processes; Apparatus for adding one or several substances in portions or in various ways to the paper, not covered by another single group of this main group

IPC and CPC are identically structured here. All 2 subcodes exist in both systems.

IPC defines codes here since 1990.

Child Classifications

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  • D21H 23/72 Plural serial stages only since 1990 IPC+CPC Available in IPC and CPC
  • D21H 23/74 Apparatus permitting switching from one technique to another since 1990 IPC+CPC Available in IPC and CPC

Top Applicants

Top Applicants (IPC)

Class D21,2013–2023, worldwide · Source: EPO PATSTAT

  1. VOITH PATENT DE 1,809
  2. STORA ENSO FI 1,467
  3. KEMIRA FI 1,086
  4. KIMBERLY-CLARK CORPORATION US 935
  5. VALMET TECHNOLOGIES FI 924
  6. VALMET SE 904
  7. P&G (PROCTER & GAMBLE COMPANY) US 862
  8. OJI HOLDINGS CORPORATION 696
  9. OMYA INTERNATIONAL CH 584
  10. SOUTH CHINA UNIVERSITY OF TECHNOLOGY 571

Top Applicants (CPC)

Class D21,2013–2023, worldwide · Source: EPO PATSTAT

  1. VOITH PATENT DE 1,857
  2. STORA ENSO FI 1,552
  3. KEMIRA FI 1,173
  4. KIMBERLY-CLARK CORPORATION US 1,107
  5. VALMET TECHNOLOGIES FI 965
  6. VALMET SE 943
  7. P&G (PROCTER & GAMBLE COMPANY) US 941
  8. OMYA INTERNATIONAL CH 821
  9. UPM-KYMMENE CORPORATION FI 512
  10. SEIKO EPSON CORPORATION JP 501