Surfactant and emulsion coatings

In recent years, water as the medium of water paint in coating production percentage increase year by year, which has become one of the main varieties of paint in the future development. Emulsion coatings play an important role in water-borne coatings, it is a polymer-based materials (film) together with fillers and additives of the coating system. Because they can be thinned with water, the construction is convenient, safe and nontoxic, low costs and excellent coating properties and other characteristics, they are widely used for Interior and exterior painting, industrial and maintenance of paint as well as others, such as fiber, paper, leather and many other application areas, plays an increasingly important role.

Competitive adsorption of surfactant is frequently asked questions in emulsion paints, paint system is complex, so it has a lot of different surfactants and a different interface. Different types of surfactants as Binder resin in the polymer or latex particles will produce competitive adsorption on the pigments surface. This mainly depends on the compatibility of base material, surfactant and surface with each other. The adsorption and desorption of surfactant may cause changes in the rheological behavior and make dispersion system to lose stability.

Competitive adsorption of surfactants are also related to associative thickeners in the coating system. Associative thickeners has a high surface activity, they have greater tendencies on hydrophobic surfaces such as latex particles. Hydrophobically modified polyurethane is the so-called HEUR thickener. If LaTeX surface not covered by the surfactant fully, activity of hydrophobic associating polymer on the surface will be adsorbed on the surface of particles, and it often lead to gel. After adding the non-ionic surfactants, it is uniform dispersion of flowing again, which suggests that non-ionic surfactant replacement surface polymer of latex particles.

These special surfactants can eliminate surface tension gradients due to surface faster than the internal when coating solvent evaporation in the applications. In addition, applications of reactive surfactant in the emulsion polymerization has received more and more attention in recent years. The emulsifier connected with the latex particles in the form of Covalent bonds, it can avoid or at least minimize a lot of problems when using traditional emulsifier, improving the stability of polymer emulsion and its film-forming properties. Read more here!