Aqueous dispersions of blocked polyisocyanates
AssigneeMiles Inc.
InventorsRobin E. Tirpak, James W. Rosthauser
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Abstract
The present invention is directed to a process for the preparation of an aqueous dispersion of a blocked polyisocyanate by reacting an aqueously dispersed polyisocyanate having an isocyanate content of at least 12% by weight, based on the weight of the polyisocyanate, with a monofunctional blocking agent which is more reactive with isocyanate groups than water at an equivalent ratio of monofunctional blocking groups to isocyanate groups of 0.5:1 to 2:1. The present invention is also directed to the aqueously dispersed blocked polyisocyanates prepared by this process and to compositions containing these polyisocyanates and an isocyanate-reactive compound.
Claims8
A process for the preparation of an aqueous dispersion of a blocked polyisocyanate which comprises reacting an aqueously dispersed polyisocyanate having an isocyanate content of at least 12% by weight, based on the weight of the polyisocyanate, with a monofunctional blocking agent which is more reactive with isocyanate groups than water at an equivalent ratio of monofunctional blocking groups to isocyanate groups of 0.5:1 to 2:1, wherein said monofunctional blocking agent comprises a member selected from the group consisting of secondary aromatic amines, N-methyl toluidines, alkyl amides, imides, lactams, mercaptans, triazoles, alkali metal bisulfites and oximes.
Dependencies are inferred from the claim text.