Process for the preparation of organic polyisocyanates having at least partially blocked isocyanate groups, compounds obtained by this process and their use in the preparation of polyurethanes, stoving varnishes or aqueous polyisocyanate solutions or dispersions

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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 July 9, 1984 and granted April 1, 1987. A European patent lasts at most 20 years from filing, so its term ended July 9, 2004.
• 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 January 9, 2010.
• 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.