D21H PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
Introduced: September 1968
Description
D21H covers pulp compositions and their formulation methods that fall outside the scope of more specific pulp-focused subclasses (D21C–D21G), including additives, fillers, and processing modifications to cellulose fibers. It also encompasses surface treatments, impregnation, and coating techniques applied to finished paper that are not addressed in other classes or subclasses, as well as specialized paper types and post-production treatments not elsewhere classified. This subclass serves as a catch-all for paper and pulp innovations that do not fit neatly into dedicated mechanical, chemical, or conversion-specific categories. Examples include paper sizing, wet-strength additives, specialized coatings, and novel pulp blends.
Title
Titles differ between systems:
IPC: 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
CPC: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
Full Title
Full titles differ between systems:
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
PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
Additional Content IPC
Glossary
finished paper paper after passing to the finishing process, creating a surface characteristic of a sheet created by either on-machine or off-machine papermaking processes. Popular text and cover finishes include smooth, vellum, felt, laid, and linen. impregnation process of treating a sheet of paper with a coating material, especially wax, so that the material penetrates into the paper. pulp means a dispersion comprising paper-making fibres and optional additives, which is to be processed, and covers the term "paper stock"; it also means dry paper-making fibres which are to be made into paper by either wet or dry processes. sizing agents substances used during paper manufacture to reduce the paper's tendency when dry to absorb liquid, allowing inks and paints to remain on the surface of the paper and to dry there, rather than be absorbed into the paper. paper stock term used to define pulp after mechanical (refining or beating) and /or chemical treatment (sizing, loading, dyeing, etc.) in the paper making process, e.g. the pulp ready to make paper.
Limiting references
Self-supporting filtering material Printing processes to produce watermarks Printing processes to produce security printing Printing processes to produce particular kinds of wallpapers Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity Identification or security features, e.g. for preventing forgery Decorative panels Wood grain effects Packaging materials of special type or form Adhesives in the form of paper or textile fabric Chemical features in the manufacture of artificial filaments and fibres Methods of producing watermarking devices Dryer section of machines for making continuous webs of paper Patterned paper prepared on the paper-making machines Filter paper making on paper-making machines Coated fibreboard Anti-coiling photographic support
Of 12 combined children, 9 exist in both systems.
3 codes are CPC-only extensions.
5 shared codes have differing titles between IPC and CPC.
IPC defines codes here since 1990.
Child Classifications
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- D21H 11/00 Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only since 1990 IPC+CPC Available in IPC and CPC
- D21H 13/00 Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material (chemical features in the manufacture of artificial fibres D01F) since 1990 IPC+CPC Available in IPC and CPC
- D21H 15/00 Pulp or paper, comprising fibres or web-forming material characterised by features other than their chemical constitution since 1990 IPC+CPC Available in IPC and CPC
- D21H 17/00 Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution since 1990 +2 CPC IPC+CPC Available in IPC and CPC
- D21H 19/00 Coated paper (coated fibreboard D21J1/08); Coating material (recording sheets characterised by the coating used to improve ink, dye or pigment receptivity B41M5/50) since 1990 IPC+CPC Available in IPC and CPC
- D21H 21/00 Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties since 1990 IPC+CPC Available in IPC and CPC
- D21H 23/00 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) since 1990 IPC+CPC Available in IPC and CPC
- D21H 25/00 After-treatment of paper not provided for in groups D21H17/00 - D21H23/00 since 1990 +1 CPC IPC+CPC Available in IPC and CPC
- D21H 27/00 Special paper not otherwise provided for, e.g. made by multi-step processes since 1990 +2 CPC −1 IPC 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