Solids Determination in Latex and Latex-Based Coatings

Abstract

Solids determination is crucial to the correct formulation of latex-based coatings. Generally, too high a level of solids can result in degradation of physical properties, while a solids content which is too low can contribute to problems in both surface and pigment binding. Although standard oven procedure has been a commonly accepted method of solids determination, test times are generally very lengthy and therefore not suitable for spot-checking formulations during processing. An alternative method is now available providing quick, accurate solids determinations in both latex and latex-based coatings. Using an electronic force balance to continuously monitor weight loss during heating, a microprocessor interprets the information and compares the sample’s weight loss to a standard drying curve. The final solids value is then extrapolated from the curve and results are available within minutes. This method gives results in direct correlation to the oven method, but in a fraction of the time. It is suitable for the laboratory as well as the production environment.