CPC technology class · C04

C04B - LIME

Lime, magnesia; slag; cements; compositions thereof, e.g. mortars, concrete or like building materials; artificial stone ; ceramics ; refractories; treatment of natural stone. 14,853 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

Compiled byPlainPatent Editorial, US Patent Intelligence Editorial Team · May 15, 2026

14,853
US patents granted: C04
Parent CPC class: 20
Active assignees: +18%
5-yr velocity

The verdict

LIME ranks #123 of 670 CPC technology areas - 14,853 US patents granted since 2015, with filing up 18% over five years.

#123
of 670 CPC technology areas: 14,853
US patents granted, 2015–2025: Ngk Insulators
leading assignee (451): +18%
filing velocity, last 5 yrs

Top assignee: NGK Insulators, Ltd. (451 patents)

CPC subclass C04B - LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE ; CERAMICS ; REFRACTORIES; TREATMENT OF NATURAL STONE - covers 14,853 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class C04 (CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES). See our CPC classification guide for how the system works.

The competitive landscape in C04B is shaped by 20 distinct companies actively filing in this space. NGK Insulators, Ltd. leads with 451 patents, followed by Halliburton Energy Services, Inc. at 417 grants and Saudi Arabian OIL Company at 271.

Filing activity in C04B is up 18% over the past five years versus 2015-2019, a relatively steady filing pace. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is C04B innovation accelerating?

US utility-patent grants per year in C04B, 2015–2025 - recent five years are up 18% versus 2015–2019.

Ngk Insulators

451
Halliburton Energy Se…

417
Saudi Arabian Oil

271
Corning Incorporated

262
Tdk

164
Rolls-royce

135
United States Gypsum

132
Mitsubishi Materials

129
Sika Technology

121
Raytheon

106
Rtx

104
Taiyo Yuden

95

What this shows Ngk Insulators is the most active filer in C04B, holding 451 of the 14,853 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 C04B
Rank	Company	Patents in C04B
#1	NGK Insulators, Ltd.	451
#2	Halliburton Energy Services, Inc.	417
#3	Saudi Arabian OIL Company	271
#4	Corning Incorporated	262
#5	TDK Corporation	164
#6	Rolls-royce Corporation	135
#7	United States Gypsum Company	132
#8	Mitsubishi Materials Corporation	129
#9	SIKA Technology Ag	121
#10	Raytheon Technologies Corporation	106
#11	RTX Corporation	104
#12	Taiyo Yuden Co., Ltd.	95
#13	Saint-gobain Ceramics & Plastics, Inc.	92
#14	KING FAHD University OF Petroleum AND Minerals	90
#15	Goodrich Corporation	87
#16	Saint-gobain Centre DE Recherches ET D'etudes Europeen	75
#17	Schlumberger Technology Corporation	72
#18	Skyworks Solutions, Inc.	68
#19	Rolls-royce High Temperature Composites, Inc.	65
#20	Sumitomo Electric Hardmetal Corp.	63

About This Class

CPC subclass C04B belongs to class C04.

14,853 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 C04B 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 C04B assignees by class footprint. Bubble size = patents in C04B. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class C04B?

CPC subclass C04B covers LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE ; CERAMICS ; REFRACTORIES; TREATMENT OF NATURAL STONE. It belongs to CPC class C04 (CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES), with 14,853 US utility patents granted since 2015.

How many patents have been filed in C04B?

14,853 US utility patents were granted in CPC subclass C04B between 2015 and 2025, based on USPTO PatentsView data.

Which company holds the most patents in C04B?

NGK Insulators, Ltd. leads C04B with 451 patents, making it the most active assignee in this technology area.

How is patent data for C04B 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., C04) is a broad technology category. Subclasses like C04B 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.