CPC Subgroup
C04B 7/421 Full Title
Hydraulic cements (calcium sulfate cements C04B11/00) > Manufacture of hydraulic cements in general > Preparing or treating the raw materials individually or as batches > Active ingredients added before, or during, the burning process (after the burning process C04B22/00, C04B24/00)
4 direct subcodes
Child Classifications
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Top Applicants
Top 10 applicants by patent filingsfor class C04, 2013–2023, worldwide · Source: EPO PATSTAT
- HALLIBURTON ENERGY SERVICES GROUP US 2,158
- CHINESE ACADEMY OF SCIENCES 1,569
- NGK INSULATORS JP 1,504
- SIKA TECHNOLOGY CH 1,181
- CORNING US 974
- WUHAN UNIVERSITY OF TECHNOLOGY 926
- UNITED STATES GYPSUM COMPANY US 882
- GE (GENERAL ELECTRIC COMPANY) US 828
- MITSUBISHI MATERIALS CORPORATION JP 792
- SAUDI ARABIAN OIL COMPANY SA 686