Protected Polyurea Acrylate Oligomers for Stable Photo-Curing Resins

The patent introduces protected groups (such as acetal, ketal, or orthoester groups) during the synthesis of polyurea acrylate oligomers that preemptively prevent the dissociation of hindered urea bonds under ambient conditions. These protected groups act as temporary blockers that stabilize the resin during synthesis, storage, and printing, while being removable under specific post-curing conditions to enable the desired bond dissociation and toughness improvement

The protected groups serve as intermediary structures that mediate between the stable resin state and the reactive state needed for toughness improvement. During synthesis and storage, the protected groups prevent premature dissociation of hindered urea bonds. Under controlled post-curing conditions (such as specific temperature, pH, or enzymatic treatment), the protected groups are removed to expose the active hindered urea bonds, enabling them to dissociate and react with water or side chain functional groups to improve material toughness

The patent combines the introduction of protected groups with the existing polyurea acrylate oligomer synthesis process. The protected groups are incorporated during the standard polyaddition reaction between diisocyanate and polyol, merging the protection function with the main synthesis pathway rather than requiring separate protection/deprotection steps. This integration minimizes additional process complexity while achieving the desired resin stability

The patent utilizes parameter changes in the synthesis conditions (such as temperature, catalyst, or reactant ratios) to control the formation and removal of protected groups. By adjusting these parameters, the protected groups can be introduced and removed efficiently within the existing synthesis framework, minimizing the increase in process complexity while ensuring resin stability during storage and enabling toughness improvement during post-curing