CPC technology class · B28

B28B — Shaping CLAY OR Other Ceramic Compositions

Shaping clay or other ceramic compositions; shaping slag; shaping mixtures containing cementitious material, e.g. plaster. 3,309 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

3,309
US patents granted
B28
Parent CPC class
20
Active assignees
+71%
5-yr velocity
Top assignee: CORNING INCORPORATED (157 patents)

CPC subclass B28B — SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER — covers 3,309 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records. This subclass sits within the broader CPC class B28 (WORKING CEMENT, CLAY, OR STONE), one of roughly 250 top-level technology categories in the Cooperative Patent Classification system jointly maintained by the USPTO and the European Patent Office. At the subclass level, four-character codes like B28B give the most practical resolution for tracking a specific technology domain without losing sight of adjacent filings. Every grant here has been classified by a USPTO examiner based on the technical disclosure in the patent specification.

The competitive landscape in B28B is shaped by 20 distinct companies actively filing in this space. CORNING INCORPORATED leads with 157 patents, followed by NGK INSULATORS, LTD. at 1,631 grants and UNITED STATES GYPSUM COMPANY at 233. Concentration at the top of the leaderboard indicates whether this technology area is dominated by a handful of incumbents or fragmented across many filers — a useful signal for investors evaluating competitive moats and for product teams mapping freedom-to-operate risk.

Filing trajectory matters as much as static counts. The yearly series on this page plots grants from 2015 through 2025, highlighting whether innovation in B28B is accelerating, plateauing, or cooling. Technology areas with rising post-2020 activity often reflect emerging markets or new platform shifts, while declining filings can signal mature domains where incremental improvement has slowed. Researchers, licensing professionals, and competitive-intelligence teams use these patterns — together with the top-assignee distribution — to decide where to invest, where to license, and where to avoid entanglement. All counts on this page come directly from USPTO PatentsView and reflect US granted utility patents only.

Is B28B innovation accelerating?

US utility-patent grants per year in B28B, 2015–2025 — recent five years are up 71% versus 2015–2019.

150200250300350400 20152016201720182019202020212022202320242025 238

Who leads B28B?

The 12 most active assignees in SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER — wider bars mean more grants

patents

What this shows Corning Incorporated is the most active filer in B28B, holding 157 of the 3,309 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

About This Class

CPC subclass B28B belongs to class B28.

3,309 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.

Frequently Asked Questions

What is CPC class B28B?
CPC subclass B28B covers SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER. It belongs to CPC class B28 (WORKING CEMENT, CLAY, OR STONE). The Cooperative Patent Classification is a hierarchical system used by the USPTO and European Patent Office to categorize patents by technology.
How many patents have been filed in B28B?
3,309 US utility patents were granted in CPC subclass B28B between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in B28B?
CORNING INCORPORATED leads B28B with 157 patents, making it the most active assignee in this technology area.
How is patent data for B28B 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 B28B provide finer granularity within that category. PlainPatent organizes data at the subclass level (4-character codes) for the most useful view of technology domains.

Learn More

Explore the patent dataset

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