Abstract: A method of forming a three-dimensional object of polyurethane, polyurea, or copolymer thereof is carried out by: (a) providing a carrier and an optically transparent member having a build surface, the carrier and the build surface defining a build region therebetween; (b) filling the build region with a polymerizable liquid, the polymerizable liquid including at least one of: (i) a blocked or reactive blocked prepolymer, (ii) a blocked or reactive blocked diisocyanate, or (iii) a blocked or reactive blocked diisocyanate chain extender; (c) irradiating the build region with light through the optically transparent member to form a solid blocked polymer scaffold and advancing the carrier away from the build surface to form a three-dimensional intermediate having the same shape as, or a shape to be imparted to, the three-dimensional object, with the intermediate containing the chain extender; and then (d) heating or microwave irradiating the three-dimensional intermediate sufficiently to form from the three-dime

Abstract: A polymerizable liquid, or resin, useful for the production by additive manufacturing of a three-dimensional object of polyurethane, polyurea, or a copolymer thereof, is described. The resin includes at least one of (i) a blocked or reactive blocked prepolymer, (ii) a blocked or reactive blocked diisocyanate, or (iii) a blocked or reactive blocked diisocyanate chain extender.