A study of optimization parameters for the development of ultraviolet cured low-acid optically clear adhesive

Abstract

This study introduced multi-quality optimization using the Taguchi method combined with response surface methodology (RSM) and the particle swarm optimization (PSO) method for synthesizing pressure sensitive adhesives (PSAs) of ultraviolet curing optically clear adhesives (OCAs). The process parameters used in this study included 2-ethylhexyl acrylate (2-EHA) monomer content, the photoinitiator content and the oligomer content using N,N-dimethylacrylamide and acrylic acid. The quality responses included the peel strength, the transmittance, the haze and the refractive index. The Taguchi method was adopted because it could reduce the number of experiments and cost, as well as effectively arriving at a single optimum parameter. The results from the Taguchi method were combined with RSM and PSO to obtain a single composition that has the optimum response for all qualities. The results of the confirmation experiment showed that the optimum parameters were 80 wt% of 2-EHA content, 4.32 wt% of photoinitiator content and 45 wt% of oligomer content, which could obtain the peel strength at 720.3 g/25.4 mm, transmittance up to 97.94%, haze of only 1.93% and refractive index at 1.48. All of qualities meet the industrial requirement of OCA PSAs.