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Expired European patentEurope

Improved drilling fluids based on a mixture of sulfonated thermoplastic polymer and an amine-treated clay

EP 0103482 B1 · Applicant: EXXON RESEARCH AND ENGINEERING COMPANY

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Overview

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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 September 13, 1983 and granted May 20, 1987. A European patent lasts at most 20 years from filing, so its term ended September 13, 2003.
  • 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 March 13, 2009.
  • 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.
FiledSeptember 13, 1983
PublishedMarch 21, 1984
GrantedMay 20, 1987
Term endedSeptember 13, 2003
Application numberEP 83305334
Classification (CPC)C09K8/36

Timeline

Timeline From EPO dates

1984198619881990199219941996199820002002Application filedSep 13, 1983PublishedMarch 21, 1984Patent grantedMay 20, 1987Term endedSep 13, 2003

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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