There are several methods for preparing a two-component aqueous polyurethane.
(1) A two-component aqueous polyurethane active hydrogen component is prepared by using an acrylate polymer having a carboxyl group and a hydroxyl group. Acrylate polymers containing carboxyl groups and hydroxyl groups are relatively expensive to prepare.
(2) Partial reaction of the hydrophilic polyether with the polyisocyanate to obtain a much more hydrophilic isocyanate component.
(3) The polyisocyanate component-NCO group is protected by a blocking agent, and when used, the active -NCO group is released under a certain temperature condition, and reacts with a polyhydroxy compound or the like to form a polyurethane.
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