Effect of a red-shifted benzotriazole UV absorber on curing depth and kinetics in visible light initiated photopolymer resins for 3D printing

We have investigated the effects of a red-shifted UV absorber in projection-microstereolithography operating under blue visible light (405 nm). A 2-(2-hydroxyphenyl)-benzotriazole derivative (Tinuvin (R) CarboProtect (R) : CarboP) was introduced as an absorbing additive. A remarkable decrease of the curing depth from over 800 mu m in the pristine resin to 65 mu m at 0.2 mol% CarboP was observed, while the polymerization and build times were somewhat increased. Microfluidic channels were accurately fabricated with the modified resin whereas the pristine photopolymer did not form any precise patterns. This demonstrates potential applications of modified UV absorbers in visible light initiating resins for precise 3D printing. (C) 2016 Published by Elsevier B.V. on behalf of The Korean Society of Industrial and Engineering Chemistry.