The identification and screening of lower toxicity solvents for contact adhesives

Contact adhesives, which bond to themselves upon contact, frequently contain hazardous air pollutants (HAPs) and volatile organic compounds (VOCs) that detrimentally impact human health and the environment. Commercial formulations containing polychloroprene, SIS, and other rubbers and resins impose demanding requirements that balance solubility, viscosity, evaporation, color, odor, and cost. In this paper, solvent compositions that contain safer solvent alternatives to the hazardous air pollutants, toluene and hexane, and which retain the solubility of contact adhesive polymers and resin in contact adhesives, are predicted with Hansen Solubility Parameters (HSP). A database of solvents selected based on health and environmental data from those available in the Hansen Solubility Parameters in Practice (HSPiP) software was used to identify binary and ternary solvent blends based on solubility, evaporation rate, and density. Promising new solvent blend candidates are experimentally tested for solubility, evaporation rate, adhesive application and edge bond strength and their performance compared to commercial formulations.