Patent Yard Sign in
Expired Australian patentAustralia

Preparation of ethylidene diacetate and/or acetic acid anhydride

AU 1983020826 · Applicant: Shell Internationale Research Maatschappij Bv

AusPat record

Overview

Drawings and full text

Its specification, documents and status are on IP Australia's AusPat.

Open the AusPat record

Read the whole patent

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

Why it's free to use

  • Filed October 31, 1983 and granted February 9, 1988. An Australian standard patent lasts 20 years from its date of patent, which is at most a year after this filing, so its term ended by October 31, 2004.
  • A pharmaceutical extension adds at most five years, so even that would have ended by October 31, 2009.
  • We check Australian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledOctober 31, 1983
GrantedFebruary 9, 1988
Term ended byOctober 31, 2004
Application numberAU 1983020826
Classification (IPC)C07C53/12 +2 more

Timeline

Timeline From IP Australia dates

1984198719901993199619992002Application filedOct 31, 1983Patent grantedFeb 9, 1988Term ended byOct 31, 2004

Sources & verification

Everything on this page comes from the IP Australia record linked above. Data from IP Australia's IPGOD, licensed under CC BY 2.5 AU.