Study on Dyeing and Simultaneous Modification of 3D ‐Printed TPU Parts by Solvent Dip‐Dyeing Method

ABSTRACT Aiming at the problem of rough and porous surfaces and the mechanical properties of thermoplastic polyurethane elastomer (TPU) parts prepared by selective laser sintering, this article used the dip‐dyeing process to improve surface modification of TPU parts. It researched the solvent type, dip‐dyeing temperature, time, pH value of the dyeing solution, and the initial concentration of dyes on the dyeing performance, surface properties, and mechanical properties of TPU parts. It analyzed the mechanism of the TPU parts immersed in solvent simultaneous modification and dyeing. After dip‐dyeing, the surface of TPU parts formed a homogeneous integument; the surface roughness was reduced from 23.3 μm of the original TPU parts to 0.3 μm of the dyed TPU parts. The apparent performance and dirt resistance of TPU parts are improved, and the colorfastness rate is 4 or more. Simultaneous modification of dyeing efficiently improved the mechanical properties of TPU parts through solvent impregnation. When DMF dyeing solution was used, the dyeing temperature was 30°C and the dyeing time was 60 s, the tensile strength of the TPU parts reached 4.51 MPa and the elongation at break reached 421.1%, which are 61.48% and 108.2% higher than that of the original TPU parts.