Waterborne overprint varnish (OPV) has a significant role in the graphic arts industry. Some of the polymers used in this coatings industry segment are non-film formers at room temperature. A plasticizer and/or a coalescent is required to help form a film properly to ensure full development of performance properties with these hard polymers. Glycol ethers, phthalates esters (such as butyl benzyl phthalate) and benzoate esters have been employed as plasticizers/coalescents for OPVs as well as ink. A new dibenzoate triblend plasticizer platform has been recently introduced for use in architectural coatings as a low VOC plasticizer/coalescent. Based on its broad range of compatibilities with polymers utilized in the coatings industry (for example, in vinyl acrylic, acrylic and styrene acrylic types), one of the triblend plasticizers, X-20, was evaluated initially in polymer dispersion/coalescent binary blends, a waterborne OPV and an ink formulation. In addition to the triblend, an entirely new monobenzoate plasticizer/coalescent will be introduced to the industry as an effective lower VOC alternative. The polymer selected for this evaluation is an industry standard hard styrene acrylic type utilized in simple starting formulations. This basic OPV evaluation includes the effect of the plasticizer/coalescent on minimum film formation temperature, adhesion to different substrates, rub resistance, alkali and water resistance, viscosity response of the polymer dispersion, gloss, and other supporting data.
