Emulsion polymer latexes are gaining increasing market interest in high-performance low-VOC waterborne architectural coatings. Weight fraction (solid concentration) and viscosity are among the most important parameters for commercially relevant solution and colloidal polymer systems. Although very high weight fractions are desired (minimizes the shipping and storage costs, and also broaden the formulation marketability), the polymer latex system must have sufficiently low viscosity to flow.<br/><br/>Molecular weight and temperature are two important factors that influence the viscosity of a solution polymer. However, molecular weight and temperature have much less impact on the viscosity of a latex. For polymer latex, the particle size and particle size distribution are much more important parameters in determining the viscosity of a latex. Additionally, factors such as ionic content can also influence the double layer surrounding latex particles which can affect both viscosity and the stability of a latex.<br/><br/>This paper will discuss the impact of variables on the viscosity and stability using a vinyl acetate latex as a model for case study. Potential routes to lowering the viscosity of the latex polymer while maintaining a high weight fraction, will be discussed. Mechanistic validation using state of the art pulsed field gradient diffusion filter NMR technology will also be discussed.

Synthetic approach for reducing viscosity in commercially relevant polymer latexes

253rd National Meeting (2017)

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