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CPC technology class · D21

D21B - Fibrous RAW Materials OR Their Mechanical Treatment

Fibrous raw materials or their mechanical treatment. 452 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

452
US patents granted
D21
Parent CPC class
20
Active assignees
+27%
5-yr velocity

The verdict

Fibrous RAW Materials OR Their Mechanical Treatment ranks #550 of 670 CPC technology areas - 452 US patents granted since 2015, with filing up 27% over five years.

#550
of 670 CPC technology areas
452
US patents granted, 2015–2025
Seiko Epson
leading assignee (111)
+27%
filing velocity, last 5 yrs
Top assignee: Seiko Epson Corporation (111 patents)

CPC subclass D21B - FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT - covers 452 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class D21 (PAPER-MAKING; PRODUCTION OF CELLULOSE). See our CPC classification guide for how the system works.

The competitive landscape in D21B is shaped by 20 distinct companies actively filing in this space. Seiko Epson Corporation leads with 111 patents, followed by Valmet AB at 20 grants and Fiberlean Technologies Limited at 14.

Filing activity in D21B is up 27% over the past five years versus 2015-2019, a sharp acceleration suggesting an emerging or fast-moving technology area. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is D21B innovation accelerating?

US utility-patent grants per year in D21B, 2015–2025 - recent five years are up 27% versus 2015–2019.

2030405060 20152016201720182019202020212022202320242025 30

Who leads D21B?

The 12 most active assignees in FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT - wider bars mean more grants

patents

What this shows Seiko Epson is the most active filer in D21B, holding 111 of the 452 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

Source USPTO PatentsView, granted utility patents As of 2015–2025 grant years
View data table
Top patent holders in CPC subclass D21B
Rank Company Patents in D21B
#1 Xyleco, Inc. 29
#2 Valmet AB 20
#3 Fiberlean Technologies Limited 14
#4 Unicharm Corporation 13
#5 Upm-kymmene Corporation 10
#6 Andritz Inc. 7
#7 Granbio Intellectual Property Holdings, Llc 5
#8 Forest Concepts, Llc 5
#9 Virent, Inc. 4
#10 Beta Renewables S.p.a. 4
#11 Westrock MWV, Llc 3
#12 The University Of New Brunswick 3
#13 Qilu University Of Technology 3
#14 API Intellectual Property Holdings, Llc 3
#15 Domtar Paper Company, Llc 3
#16 Bouldin Corporation 3
#17 Green Extraction Technologies 3
#18 Zuiko Corporation 2
#19 Andritz OY 2
#20 Department Of Biotechnology 2

About This Class

CPC subclass D21B belongs to class D21.

452 patents were granted in this class between 2015 and 2025.

20 companies actively patent in this space.

Classification System

Cooperative Patent Classification (CPC) is a hierarchical patent classification system used by the USPTO and EPO.

← All Technology Classes Technology Rankings →

Footprint here vs. claim strategy

Each dot is a leading D21B assignee, placed by how many patents it holds in this class (horizontal) against its company-wide average claims per patent (vertical) - a read on whether the class is led by broad-but-shallow filers or focused deep-claim players.

Top 14 D21B assignees by class footprint. Bubble size = patents in D21B. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Top 14 D21B assignees by class footprint. Bubble size = patents in D21B. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 510152025 010203040 Patents in D21B Avg claims / patent (company-wide) XylecoValmet AbFiberleanUnicharmUpm-kymmeneAndritzGranbio Intellectual…Forest ConceptsVirentBeta Renewables S p AWestrock MwvThe University of New…Qilu University of Te…Api Intellectual Prop…
Top 14 D21B assignees by class footprint. Bubble size = patents in D21B. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class D21B?
CPC subclass D21B covers FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT. It belongs to CPC class D21 (PAPER-MAKING; PRODUCTION OF CELLULOSE), with 452 US utility patents granted since 2015.
How many patents have been filed in D21B?
452 US utility patents were granted in CPC subclass D21B between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in D21B?
Seiko Epson Corporation leads D21B with 111 patents, making it the most active assignee in this technology area.
How is patent data for D21B collected?
Patent data comes from USPTO PatentsView, a public research dataset maintained by the United States Patent and Trademark Office. It covers all US granted utility patents and assigns CPC codes based on the technology described in each patent.
What is the difference between CPC class and subclass?
A CPC class (e.g., D21) is a broad technology category. Subclasses like D21B provide finer granularity within that category. PlainPatent organizes data at the subclass level (4-character codes) for the most useful view of technology domains.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from USPTO PatentsView - official U.S. government patent data. See our methodology for computation details. Retrieved and formatted by PlainPatent Editorial

Every figure on PlainPatent is rendered directly from USPTO source data, no number is typed in by an editor. This page draws directly on USPTO source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.