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PCE
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DIFF Subgroup
D21H 23/14

by selecting point of addition or time of contact between components

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 pulp; After-treatment of added substances in the pulp > Controlling the addition > by selecting point of addition or time of contact between components

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 pulp; After-treatment of added substances in the pulp > Controlling the addition > by selecting point of addition or time of contact between components

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

1 shared codes have differing titles between IPC and CPC.

IPC defines codes here since 1990.

Child Classifications

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  • D21H 23/16 Addition before or during pulp beating or refining (disintegrating fibrous raw materials in mills in the presence of chemical agents D21B1/16; methods of beating D21D1/02; methods of refining D21D1/20) since 1990 IPC+CPC Available in IPC and CPC
  • D21H 23/18 Addition at a location where shear forces are avoided before sheet-forming, e.g. after pulp beating or refining 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