How can I balance low, mid and high shear viscosities when utilizing hydrophobic coalescent aids?
In developing a low odor interior semigloss formulation containing UCAR Latex 626 we used the low odor coalescent Velate 262 made by Velsicol. This solvent is very hydrophobic and results in extremely efficient and high viscosity response with associative thickeners. In our initial formula, thickened entirely with associative thickeners, we obtained an unacceptably high mid-shear (KU) viscosity and unacceptable low- shear (Brookfield) and high-shear (ICI) viscosities. To offset the hydrophobicity of the Velate 262 and allow more formulating latitude with the associative thickeners, the dispersants and surfactants were replaced with more hydrophilic alternatives. We also found that adding 1.25# per 100 gallons CELLOSIZE™ QP-4400 improved the rheology of the paint with increased Brookfield viscosity. We were then able to use UCAR POLYPHOBE TR-117 to build the ICI viscosity to an acceptable level while maintaining the proper KU viscosity. Another benefit of the added CELLOSIZE QP-4400 was
