Enhanced optical properties and thermal stability of optically clear adhesives

To improve the optical properties of acrylic pressure-sensitive adhesives (PSAs) for liquid crystal displays (LCDs), hafnium carboxyethyl acrylate (HCA) was introduced as high refractive index material. Also, UV-curing was used to realize rapid crosslinking so as to enhance the degree of thermal stability. A prism coupler, a UV–visible spectrometer and a thermogravimetric analyzer were employed to assess the optical properties and thermal stability. The results show that the refractive index of the acrylic PSAs with HCA increases suitably compared to that of binder acrylic PSAs in the visible wavelength. Also, a substantial effect is shown on the thermal stability in that hafnium carboxyethyl acrylates are crosslinked due to the presence of tetra-functional acrylic groups caused by the rapid UV-curing.