US Patent 11981778 Chemical recycling of additively manufactured objects

Provided is a method of recycling an additively manufactured object into a reusable thermoplastic polymer, which method in some embodiments may include: (a) providing at least one additively manufactured object produced by stereolithography from a dual cure resin, the object comprising (i) a light polymerized polymer, and (ii) a heat polymerized polymer intermixed with said light polymerized polymer; (b) comminuting the object to produce a particulate material therefrom; (c) contacting the particulate material to a polar, aprotic solvent for a time and at a temperature sufficient to extract the heat polymerized polymer from the particulate material into said solvent, leaving residual particulate material comprising said light polymerized polymer in solid form; (d) separating the residual particulate material from said solvent; and then (e) separating the heat polymerized polymer from said solvent to provide a reusable thermoplastic polymer material in solid form.