Characterization of an acrylic pressure-sensitive adhesive blended with hydrophilic monomer exposed to hygrothermal aging: Assigning cloud point resistance as an optically clear adhesive for a touch screen panel

Optically clear adhesive (OCA) is a key material for assembling a touch screen panels (TSP). TSPs are now applied to many devices; therefore, their preparation and adhesion performance examination including durability can be beneficial work. Cloud point resistance means that a material does not have a hazy appearance under any environment, especially under sudden temperature and humidity changes. It is a critical property for an OCA because it is directly related to image display on a TSP. A hydrophilic component needs to be incorporated to the OCA, and 2-hydroxyethyl acrylate (HEA) was selected as the monomeric hydrophilic component. The change in adhesion performance under hygrothermal aging conditions was investigated. The aging behavior was also monitored using infrared (IR) and Raman spectra and chemiluminescence (CL) analysis. The HEA-containing pressure-sensitive adhesive (PSA) exhibited a good cloud point resistance and adhesion performance along with stable adhesion properties during aging. This consequence is considered suitable behavior for the prepared PSA as an OCA.