Process for the after treatment of aluminium oxide layers with aqueous solutions containing alkali silicate, and its application during the manufacture of supports for offset printing plates

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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.

Why it's free to use

• Filed August 22, 1983 and granted January 13, 1988. A European patent lasts at most 20 years from filing, so its term ended August 22, 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 February 22, 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.