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IPC Subgroup
D21H 23/12

by measuring properties of the formed web

Introduced: January 1990

Last revised: January 2006

Full Title

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 measuring properties of the formed web

Classification Context

Section:
TEXTILES; PAPER
Class:
PAPER-MAKING; PRODUCTION OF CELLULOSE
Subclass:
PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES ,; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS OR SUBCLASS; PAPER NOT OTHERWISE PROVIDED FOR

Top Applicants

Top 10 applicants by patent filingsfor 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