Reactive Binders in Detergent Granulation: Understanding the Relationship Between Binder Phase Changes and Granule Growth under Different Conditions of Relative Humidity

The increasing, tendency to enhance consumer products with added functionality is leading to ever more complex products that are manufactured at large scale in conventional processes. Hence, it is important that process operating conditions are matched to the product requirements. We report on the fundamental characteristics of the reactive binder, LAS acid (HLAS), used in detergent granulation, in relation to its wetting behavior and viscosity as it is neutralized by its reaction with sodium carbonate, and how the phase changes are affected by relative humidity (RH) and temperature, in order to establish the relationship between the binder phase changes and granule formation and growth. We have found that the higher the degree of neutralization, the lower the tendency of the liquid to wet the particles (the binder behaves as a sticky paste) and that wetting behavior is strongly dependent on RH. The latter highlights the importance of controlling the environmental conditions during processing and storage of the materials.