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Expired European patentEurope

Production of stable aqueous silica sol

EP 0442268 B1 · Applicant: NISSAN CHEMICAL INDUSTRIES LTD.

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Listed from its EPO record in Patent Yard's archive of European patents past their term. Its claims, description and drawings are in the EPO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Filed January 16, 1991 and granted May 25, 1994. A European patent lasts at most 20 years from filing, so its term ended January 16, 2011.
  • A supplementary protection certificate, which can extend a medicine or crop-protection patent, adds at most five and a half years, so even that would have ended by July 16, 2016.
  • We check European rights only. A US or other national patent in its family could still be in force: check its family on Espacenet or Google Patents.
FiledJanuary 16, 1991
PublishedAugust 21, 1991
GrantedMay 25, 1994
Term endedJanuary 16, 2011
Application numberEP 91100432
Classification (CPC)C01B33/149

Timeline

Timeline From EPO dates

1992199419961998200020022004200620082010Application filedJan 16, 1991PublishedAug 21, 1991Patent grantedMay 25, 1994Term endedJan 16, 2011

Sources & verification

Official EPO records

Full published documentClaims, description and drawings as a PDF.EPOEuropean Patent RegisterProcedure, status, file inspection and legal events.EPOLinked open EP data recordThe bibliographic record this page is built from.EPO

Cross-check elsewhere

Google PatentsFull text, worldwide family, citing patents and legal events.patents.google.comEspacenetNational family members and their legal status.European Patent Office

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