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

Introduced: September 1968

Last revised: January 1990

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

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.

Additional Content

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

Related Keywords

CARDBOARDCOATING paperDYEING of paper or cardboardcoated or multiple paper or cardboardMETALLISING paperimpregnating or coating of PAPERkinds of PAPERPAPER wall coveringsPULP compositions for paper and the likeSECURITY(-IES) paperTOILET -paperWRITING paper

9 direct subcodes

Child Classifications

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D21H 11/00 Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
D21H 13/00 Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
D21H 15/00 Pulp or paper, comprising fibres or web-forming material characterised by features other than their chemical constitution
D21H 17/00 Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
D21H 19/00 Coated paper; Coating material
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
D21H 23/00 Processes or apparatus for adding material to the pulp or to the paper
D21H 25/00 After-treatment of paper not provided for in groups
D21H 27/00 Special paper not otherwise provided for, e.g. made by multi-step processes

Top Applicants

Top 10 applicants by patent filingsfor 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