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Expired European patentEurope

Process for preparing crystals of anhydrous sodium sulfide

EP 0361998 B1 · Applicant: SANKYO KASEI CO., 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 August 23, 1989 and granted December 7, 1994. A European patent lasts at most 20 years from filing, so its term ended August 23, 2009.
  • 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 February 23, 2015.
  • 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.
FiledAugust 23, 1989
PublishedApril 4, 1990
GrantedDecember 7, 1994
Term endedAugust 23, 2009
Application numberEP 89402326
Classification (CPC)C01B17/38

Timeline

Timeline From EPO dates

1990199219941996199820002002200420062008Application filedAug 23, 1989PublishedApril 4, 1990Patent grantedDec 7, 1994Term endedAug 23, 2009

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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