Additive production process with a thermoplastic radically cross-linkable construction material

A method of producing an article in an additive manufacturing method from a precursor, comprising:

• I) depositing a first layer of a free-radically crosslinked build material corresponding to a first selected cross section of the precursor on a carrier;
• II) depositing a further layer of the free-radically crosslinked build material corresponding to a further selected cross section of the precursor onto the first layer or another previously applied layer of the free-radically crosslinked build material;
• III) repeating step II) until the precursor is formed;
• wherein the depositing of the free-radically crosslinked build material at least in step II) comprises exposing and/or irradiating a selected region of a free-radically crosslinkable build material corresponding to the respectively selected cross section of the precursor;
• wherein the carrier is disposed within a container providing the free-radically crosslinkable build material, wherein the carrier is vertically raisable counter to the direction of gravity and wherein the carrier is additionally raised by a predetermined distance prior to each step II), such that a layer of the free-radically crosslinkable build material forms below a lowermost layer of the build material as viewed in a vertical direction;
• wherein the free-radically crosslinkable build material comprises a thermoplastic free-radically crosslinkable polyurethane having a urethane group content of ≥15% by weight to ≤30% by weight and a photoinitiator;
• and
• wherein the free-radically crosslinkable build material comprises an isocyanate trimerization catalyst;
• wherein the free-radically crosslinkable build material is heated in step II) to a processing temperature greater than a melting point, determined by dynamic differential calorimetry, first heating, at a heating rate of 20 K/min, of the free-radically crosslinkable polyurethane;
• wherein the free-radically crosslinkable polyurethane has a melting point, determined by dynamic differential calorimetry, first heating, at a heating rate of 20 K/min, of ≥50° C.;
• and
• wherein, after step III), the article is formed by allowing the precursor to cool to a temperature of about 20° C., or wherein, after step III), the article is formed by performing step IV):
• IV) performing a chemical reaction in the precursor obtained after step III) to obtain the article.