CPC technology class · D21

D21J - Fibreboard

Fibreboard; manufacture of articles from cellulosic fibrous suspensions or from papier-mache. 270 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

Compiled by PlainPatent · May 15, 2026

270
US patents granted: #7/7
in D21: 3.3%
D21 class share: +100%
5-yr velocity

The verdict

According to USPTO PatentsView, Fibreboard ranks #588 of 670 CPC technology areas - 270 US patents granted since 2015, with recorded grant volume up 100% over five years.

#588
of 670 CPC technology areas: 270
US patents granted, 2015–2025: Footprint International
leading assignee (20): +100%
grant velocity, last 5 yrs

How D21J's grant cadence moved

Between 2020–2024, D21J recorded 142 grants versus 71 in 2015–2019 (+100% equal-window velocity). Across complete years, output peaked in 2024 at 43 grants and bottomed in 2016 at 5 (+760% peak-over-trough). Lead assignee Footprint International, LLC holds 7.4% of the class ; the top three share 14.4%.

Leaderboard read

D21J concentration, lead at 7.4%

Footprint International, LLC leads this historical grant record at 7.4% of D21J - foreign corporation assignees hold 51% of class grants (69 of 136). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share: 7.4%
Top three share: 14.4%
Lead over #2: 9

Where D21J sits inside D21

Among 7 subclasses in D21 (PAPER-MAKING; Production OF Cellulose), D21J ranks #7 and holds 3.3% 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 D21B 452 D21G 371 D21D 314

Rising assignees active in D21J

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 Papacks Sales GMBH 4.00x 1 → 4 company-wide · 8 in D21J
#2 Acorn West LLC 2.50x 2 → 5 company-wide · 5 in D21J
#3 Footprint International, LLC 2.40x 5 → 12 company-wide · 20 in D21J
#4 Celwise AB 2.00x 2 → 4 company-wide · 8 in D21J
#5 Golden Arrow Printing Technology (KUNSHAN) Co., Ltd. 1.33x 3 → 4 company-wide · 7 in D21J

D21J grants by year, peak 2024 (43)

US utility-patent grants per year in D21J, 2015–2025 - recent five years are up 100% versus 2015–2019.

Footprint Internationa…

20
Smart Planet

11
Papacks Sales

8
Celwise Ab

8
Golden Arrow Printing…

7
Golden Arrow Painting

6
Acorn West

5
Henry Molded Products

5
Westrock Mwv

4
Pulpac Ab

4
Sig Technology

3
Usg Interiors

3

What this shows Footprint Internationa… is the most active filer in D21J, holding 20 of the 270 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

View data table

Top patent holders in CPC subclass D21J
Rank	Company	Patents in D21J
#1	Footprint International, LLC	20
#2	Smart Planet Technologies, Inc.	11
#3	Papacks Sales GMBH	8
#4	Celwise AB	8
#5	Golden Arrow Printing Technology (KUNSHAN) Co., Ltd.	7
#6	Golden Arrow Painting Co., Ltd.	6
#7	Acorn West LLC	5
#8	Henry Molded Products, Inc.	5
#9	WestRock MWV, LLC	4
#10	PulPac AB	4
#11	SIG Technology AG	3
#12	USG Interiors, LLC	3
#13	Cascades Canada ULC	3
#14	Congruens Group, LLC	3
#15	Organoclick AB	3
#16	Huhtamaki Molded Fiber Technology B.V.	3
#17	Yulan Green Technology Co., Ltd.	3
#18	Borregaard AS	2
#19	ECO.LOGIC Brands Inc.	2
#20	Fibria Innovations Inc.	2

Footprint here vs. claim strategy

Each dot is a leading D21J 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 D21J assignees by class footprint. Bubble size = patents in D21J. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Questions about D21J

Which company holds the most patents in D21J?

Footprint International, LLC leads D21J with 20 patents (7.4% of the subclass). By PatentsView assignee type, foreign corporations account for 51% of class grants.

Which D21J assignees grew fastest recently?

Among assignees with ≥5 grants in D21J, Papacks Sales GMBH shows the highest company-wide grant multiple (4.00x: 1 grants in 2019–2021 → 4 in 2022–2024) while holding 8 patents in this subclass. Growth is company-wide, not class-only.

How does D21J compare inside parent class D21?

Inside D21 (PAPER-MAKING; Production OF Cellulose), D21J ranks #7 of 7 subclasses by grant volume and holds 3.3% of the parent class total. The largest sibling is D21H (4,080 grants).

What to do with this data

D21J in context - here's where to go next.

Footprint International, LLC leads D21J with 20 grants in this class. See full portfolio
D21J ranks #588 of 670 by grant volume among all tracked CPC technology areas. See the ranking
Inside parent class D21, the largest sibling subclass is D21H with 4,080 grants. Explore D21H

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

Methodology - D21J figures are USPTO PatentsView granted-utility totals for this subclass (270 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.