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Expired European patentEurope

Process for making non-porous, micron-sized high purity silica

EP 0517841 B1 · Applicant: CABOT CORPORATION

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Overview

The published document from the EPO: abstract, claims, description and drawings. Open it full size

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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 February 28, 1991 and granted December 14, 1994. A European patent lasts at most 20 years from filing, so its term ended February 28, 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 August 28, 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.
FiledFebruary 28, 1991
PublishedDecember 16, 1992
GrantedDecember 14, 1994
Term endedFebruary 28, 2011
Application numberEP 91906293
Classification (CPC)C03C1/006 +2 more

Timeline

Timeline From EPO dates

1992199419961998200020022004200620082010Application filedFeb 28, 1991PublishedDec 16, 1992Patent grantedDec 14, 1994Term endedFeb 28, 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

Everything on this page comes from the EPO record linked above. EPO data used under CC BY 4.0.