Methods for producing three-dimensional objects

A method of forming a three-dimensional object comprised of polyurethane, polyurea, or copolymer thereof, said method comprising:

• (a) providing a carrier and an optically transparent member having a build surface, said carrier and said build surface defining a build region therebetween;
• (b) filling said build region with a polymerizable liquid, said polymerizable liquid comprising at least one of:
• (i) a blocked or reactive blocked prepolymer, (ii) a blocked or reactive blocked diisocyanate, and (iii) a blocked or reactive blocked chain extender;
• (c) irradiating said build region with light through said optically transparent member to form a solid blocked polymer scaffold and advancing said carrier away from said build surface to form a three-dimensional intermediate having the same shape as, or a shape to be imparted to, said three-dimensional object, with said intermediate containing said at least one of said blocked or reactive blocked prepolymer, blocked or reactive blocked diisocyanate, and blocked or reactive blocked chain extender;
• wherein said irradiating and/or said advancing steps are carried out while also concurrently:
• (i) continuously maintaining a dead zone of polymerizable liquid in contact with said build surface, and
• (ii) continuously maintaining a gradient of polymerization zone between said dead zone and said solid blocked polymer scaffold and in contact with each thereof, said gradient of polymerization zone comprising said polymerizable liquid in partially cured form;
• and then
• (d) heating or microwave irradiating said three-dimensional intermediate sufficiently to form from said three-dimensional intermediate said three-dimensional object comprised of polyurethane, polyurea, or copolymer thereof.