Formulating water-based systems with propylene-oxide-based glycol ethers

To comply with environmental regulations,formulators have reformulated to w ater-based systems using non-hazardous air pollutants (non-HAP) cosolvents and developed new resin technology. In fully formulated wafer-based systems , however, Changing the solvent system to meet environmental regulations ha s wide ranging effects on viscosity, surface defects, film shrinkage, adhes ion, and durability. Formulators often adjust paint viscosity by balancing the levels of cosolvents, surfactants, and rheology modifiers. Reformulatin g with non-HAPs solvents such as propylene oxide-based glycol ethers (PG-gl ycol ethers) helps reduce volatile organic content (VOC) to meet environmen tal compliance and eliminates HAPs reporting requirements. When replacing e thylene oxide-based glycol ethers (EG-glycol ethers) with their PG-glycol e thers, reformulation seems simple enough, particularly if evaporation rates and solubility parameters are matched. A drop-in replacement, however, req uires optimization. This study compares the use of PG-glycol ethers in four architectural latex paints and assesses their effects on rheology, drying, and some key performance attributes.