PlainPatent

CPC technology class · B28

B28C - Preparing CLAY

Preparing clay; producing mixtures containing clay or cementitious material, e.g. plaster. 511 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

511
US patents granted
B28
Parent CPC class
20
Active assignees
+71%
5-yr velocity

The verdict

Preparing CLAY ranks #540 of 670 CPC technology areas - 511 US patents granted since 2015, with filing up 71% over five years.

#540
of 670 CPC technology areas
511
US patents granted, 2015–2025
Oshkosh
leading assignee (50)
+71%
filing velocity, last 5 yrs
Top assignee: Oshkosh Corporation (50 patents)

CPC subclass B28C - PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER - covers 511 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class B28 (WORKING CEMENT, CLAY, OR STONE). See our CPC classification guide for how the system works.

The competitive landscape in B28C is shaped by 20 distinct companies actively filing in this space. Oshkosh Corporation leads with 50 patents, followed by United States Gypsum Company at 19 grants and Carboncure Technologies Inc. at 19.

Filing activity in B28C is up 71% 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 B28C innovation accelerating?

US utility-patent grants per year in B28C, 2015–2025 - recent five years are up 71% versus 2015–2019.

203040506070 20152016201720182019202020212022202320242025 54

Who leads B28C?

The 12 most active assignees in PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER - wider bars mean more grants

patents

What this shows Oshkosh is the most active filer in B28C, holding 50 of the 511 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 B28C
Rank Company Patents in B28C
#1 Oshkosh Corporation 50
#2 United States Gypsum Company 19
#3 Carboncure Technologies Inc. 19
#4 Verifi Llc 16
#5 Alkon Corporation 13
#6 GCP Applied Technologies Inc. 9
#7 En-tech Corporation 9
#8 KYB Corporation 8
#9 Quipip, Llc 8
#10 CIFA S.p.a. 7
#11 Con-tech Manufacturing, Inc. 7
#12 Sebastos Technologies, Inc. 7
#13 Yoshino Gypsum Co., Ltd. 6
#14 Giatec Scientific Inc. 5
#15 Bautex Systems, Llc 5
#16 ICON Technology, Inc. 4
#17 J&P Invesco Llc 4
#18 Concrete Products Group Llc 4
#19 U.s. Well Services, Llc 3
#20 Kangwon National University University-industry Cooperation Foundation 3

About This Class

CPC subclass B28C belongs to class B28.

511 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 B28C 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 B28C assignees by class footprint. Bubble size = patents in B28C. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Top 14 B28C assignees by class footprint. Bubble size = patents in B28C. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 510152025 0102030405060 Patents in B28C Avg claims / patent (company-wide) OshkoshUnited States GypsumCarboncureVerifiAlkonGcp AppliedEn-techKybQuipipCifa S P ACon-tech ManufacturingSebastosYoshino GypsumGiatec Scientific
Top 14 B28C assignees by class footprint. Bubble size = patents in B28C. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class B28C?
CPC subclass B28C covers PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER. It belongs to CPC class B28 (WORKING CEMENT, CLAY, OR STONE), with 511 US utility patents granted since 2015.
How many patents have been filed in B28C?
511 US utility patents were granted in CPC subclass B28C between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in B28C?
Oshkosh Corporation leads B28C with 50 patents, making it the most active assignee in this technology area.
How is patent data for B28C 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., B28) is a broad technology category. Subclasses like B28C 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.