PlainPatent

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 grant trajectory.

452
US patents granted
#4/7
in D21
5.5%
D21 class share
+11%
5-yr velocity

The verdict

According to USPTO PatentsView, Fibrous Raw Materials Or Their Mechanical Treatment ranks #550 of 670 CPC technology areas - 452 US patents granted since 2015, with recorded grant volume up 11% over five years.

#550
of 670 CPC technology areas
452
US patents granted, 2015–2025
Seiko Epson
leading assignee (111)
+11%
grant velocity, last 5 yrs

How D21B's grant cadence moved

Between 2020–2024, D21B recorded 217 grants versus 195 in 2015–2019 (+11% equal-window velocity). Across complete years, output peaked in 2021 at 57 grants and bottomed in 2018 at 32 (+78% peak-over-trough). Lead assignee Xyleco, Inc. holds 6.4% of the class ; the top three share 13.9%.

Leaderboard read

D21B concentration, lead at 6.4%

Xyleco, Inc. leads this historical grant record at 6.4% of D21B - foreign corporation assignees hold 55% of class grants (102 of 185). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share
6.4%

29 of 452 grants

Top three share
13.9%

of the class's recorded grants

Lead over #2
9

more grants than Valmet AB

Where D21B sits inside D21

Among 7 subclasses in D21 (PAPER-MAKING; Production OF Cellulose), D21B ranks #4 and holds 5.5% of the parent class's 8,169 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

D21H 4,080 D21C 1,427 D21F 1,255 D21G 371 D21D 314 D21J 270

Rising assignees active in D21B

Company-wide grant multiples (2022–2024 vs 2019–2021) among assignees with ≥5 patents in this subclass. Growth is company-wide; class patent counts are subclass-specific.

  1. #1 Valmet AB 1.96x 22 → 43 company-wide · 20 in D21B
  2. #2 Granbio Intellectual Property Holdings, LLC 1.53x 15 → 23 company-wide · 5 in D21B
  3. #3 Andritz Inc. 0.89x 37 → 33 company-wide · 7 in D21B
  4. #4 Fiberlean Technologies Limited 0.68x 19 → 13 company-wide · 14 in D21B
  5. #5 Upm-kymmene Corporation 0.67x 52 → 35 company-wide · 10 in D21B

D21B grants by year, peak 2021 (57)

US utility-patent grants per year in D21B, 2015–2025 - recent five years are up 11% 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

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

Questions about D21B

Which company holds the most patents in D21B?
Seiko Epson Corporation leads D21B with 111 patents (6.4% of the subclass). By PatentsView assignee type, foreign corporations account for 55% of class grants.
Which D21B assignees grew fastest recently?
Among assignees with ≥5 grants in D21B, Valmet AB shows the highest company-wide grant multiple (1.96x: 22 grants in 2019–2021 → 43 in 2022–2024) while holding 20 patents in this subclass. Growth is company-wide, not class-only.
How does D21B compare inside parent class D21?
Inside D21 (PAPER-MAKING; Production OF Cellulose), D21B ranks #4 of 7 subclasses by grant volume and holds 5.5% of the parent class total. The largest sibling is D21H (4,080 grants).

What to do with this data

D21B in context - here's where to go next.

Figures reflect USPTO PatentsView grant data through 2026-05-15; pending applications not yet granted are not counted.

Methodology - D21B figures are USPTO PatentsView granted-utility totals for this subclass (452 grants in the tracked window).

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.