Development of a washable and antistatic waterborne polyurethane acrylate for dual photo-thermal curing vat photopolymerization three-dimensional printing

Abstract

Traditional photocurable three-dimensional (3D) printing materials rely on organic solvent cleaning, emit high volatile organic compounds, have insufficient mechanical properties, and easily generate static charge. Herein, we developed a water-washable, antistatic, photo-thermal dual-curable waterborne polyurethane acrylate for digital light processing‑based vat photopolymerization 3D printing. A waterborne polyurethane skeleton was constructed using polypropylene glycol, isocyanate, and 2,2-dimethylolpropionic acid, and a tertiary amine blocking agent with photosensitive groups was introduced to synthesize prepolymers containing thermally reversible urea bonds. An ionic antistatic agent was compounded to prepare a photosensitive resin, which was then molded via photo-thermal dual curing. The effects of isocyanate type and content, chain extender, diluent, and antistatic agent on material properties were systematically investigated. Results showed that the material exhibited optimal overall performance with 4,4’-dicyclohexylmethane diisocyanate as the isocyanate, isophorone diamine as the chain extender, N,N-dimethylacrylamide as the diluent, and 1.0 wt% octadecyltrimethylammonium chloride as the antistatic agent. After thermal curing at 110°C for six hours, the material achieved a tensile strength of 26.8 MPa and an elongation at break of 110%, maintaining stable antistatic performance (surface resistivity < 1 × 1010 Ω) within 28 days. The material is fully water-washable with zero volatile organic compound emissions, integrating high strength-toughness, long-term antistatic property, and environmental friendliness. This work provides a new strategy for developing eco-friendly functional 3D printing materials.