US Patent 11655329 Delayed action catalysts for dual cure additive manufacturing resins

Provided herein is a dual cure resin useful for the production of an object by additive manufacturing, comprising or consisting essentially of: (a) a photoinitiator; (b) not more than 5, 10 or 20 ppm of a polyurethane catalyst (e.g., tin, tertiary amine, bismuth, zinc, zirconium, or nickel catalysts); (c) a polyol; (d) free (i.e., unblocked) polyisocyanate; and (e) blocked polyisocyanate, the isocyanate groups of which are blocked by reaction with an amine (meth)acrylate blocking agent. Methods of making an object with the resin are also provided.