Optimization of UV LED-Curable Ink for Reverse-Offset Roll-to-Plate (RO-R2P) Printing

摘要

Reverse-offset roll-to-plate printing has become increasingly popular in the printing industry because of the ease with which the printing process can be manipulated to achieve a high-resolution pattern with line widths as narrow as 5 mu m with precision and accuracy. The printing procedure involves three stages, and a roller is required to transfer ink from each stage. The substrates used throughout this experiment were chosen by measuring their contact angles (theta) and using them in accordance with the sequence: theta (Stage 1) >theta (roller) >theta (Stage 2) and theta (Stage 3). An ultraviolet (UV) light-emitting diode (LED)-curable ink was used during the printing process; however, the pristine solution of this ink was unsuitable for printing a final pattern on the substrate because of its viscosity. Diluting the solution of the UV LED-curable ink with 40% CH3OH resulted in reduced viscosity. The original solution had a viscosity of approximately 40.7 cP whereas that of the diluted solution was approximately 25 cP. The two solutions behaved as non-Newtonian, dilatant, shear-thickening fluids. The UV LED-curable ink solutions, both dilute and non-dilute, were successfully printed by use of an inkjet printer and three-dimensional printing methods.