D21H 21/44 Latent security elements, i.e. detectable or becoming apparent only by use of special verification or tampering devices or methods
Full Title
Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties > characterised by function or properties in or on the paper (D21H19/66, D21H27/02 take precedence) > Agents facilitating proof of genuineness or preventing fraudulent alteration, e.g. for security paper (watermarking B41M3/10, D21F1/44; security printing B41M3/14; securities or banknotes characterised by colour effects B42D25/29, B42D25/30; testing paper currency or valuable papers for genuineness G07D7/00) > Latent security elements, i.e. detectable or becoming apparent only by use of special verification or tampering devices or methods
2 direct subcodes
Child Classifications
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- D21H 21/46 Elements suited for chemical verification or impeding chemical tampering, e.g. by use of eradicators
- D21H 21/48 Elements suited for physical verification, e.g. by irradiation
Top Applicants
Top 10 applicants by patent filingsfor class D21, 2013–2023, worldwide · Source: EPO PATSTAT
- VOITH PATENT DE 1,857
- STORA ENSO FI 1,552
- KEMIRA FI 1,173
- KIMBERLY-CLARK CORPORATION US 1,107
- VALMET TECHNOLOGIES FI 965
- VALMET SE 943
- P&G (PROCTER & GAMBLE COMPANY) US 941
- OMYA INTERNATIONAL CH 821
- UPM-KYMMENE CORPORATION FI 512
- SEIKO EPSON CORPORATION JP 501