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Expired European patentEurope

Process for the chlorine-free bleaching and delignification of pulp

EP 0442425 B1 · Applicant: SKW Trostberg Aktiengesellschaft

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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 February 11, 1991 and granted March 30, 1994. A European patent lasts at most 20 years from filing, so its term ended February 11, 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 11, 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 11, 1991
PublishedAugust 21, 1991
GrantedMarch 30, 1994
Term endedFebruary 11, 2011
Application numberEP 91101890
Classification (CPC)D21C9/147 +2 more

Timeline

Timeline From EPO dates

1992199419961998200020022004200620082010Application filedFeb 11, 1991PublishedAug 21, 1991Patent grantedMarch 30, 1994Term endedFeb 11, 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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