Skip to content
PCE
Search Classifications
Search for IPC and CPC classification codes or keywords
IPC Subclass
D21B

FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT

Introduced: September 1968

Classification Context

Section:
TEXTILES; PAPER
Class:
PAPER-MAKING; PRODUCTION OF CELLULOSE
Subclass:
FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT

Description

D21B covers the preparation and mechanical processing of fibrous raw materials destined for papermaking, including pulping processes, fiber separation, and treatment operations prior to paper formation. This subclass encompasses both wood and non-wood fiber sources (such as plant stalks, recycled paper, and textile waste) and their conversion into usable pulp through chemical, mechanical, or combination methods. The classification includes fiber washing, screening, cleaning, and other mechanical treatments that condition raw fibers for subsequent papermaking stages. D21B excludes the actual papermaking process itself (covered by D21D-D21H) and fiber-to-pulp chemical conversion that is part of integrated pulping systems.

Additional Content

Splitting wood; manufacture of veneer, wooden sticks, wood shavings, wood fibres or wood powder Obtaining fibres from plant material (mechanical separation) Hackling or heckling machines Pretreatment of the finely-divided materials before digesting Methods of beating or refining pulp Purification of the pulp suspension by mechanical means

Related Keywords

pretreatment of fibrous cellulosic materials in paper-makingDISINTEGRATING of raw material for paper-makingobtaining FIBRES for paper-makingFIBRILLATING raw material peculiar to paper-makingGRINDING of raw material for paper-makingMILLING raw material peculiar to paper-makingtreatment of RAGS in papermakingSHREDDING of fibrous materialSHREDDING of raw material for papermakingtreatment of WASTE paper in paper-making

1 direct subcode

Child Classifications

Navigate with arrow keys, Enter to open

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