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

To comply with environmental regulations,formulators have reformulated to water-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 has wide ranging effects on viscosity, surface defects, film shrinkage, adhesion, and durability. Formulators often adjust paint viscosity by balancing the levels of cosolvents, surfactants, and rheology modifiers. Reformulating with non-HAPs solvents such as propylene oxide-based glycol ethers (PG-glycol ethers) helps reduce volatile organic content (VOC) to meet environmental compliance and eliminates HAPs reporting requirements. When replacing ethylene oxide-based glycol ethers (EG-glycol ethers) with their PG-glycol ethers, reformulation seems simple enough, particularly if evaporation rates and solubility parameters are matched. A drop-in replacement, however, requires 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.