Hydrophobic coatings from emulsion polymers

One important feature of protective coatings which determines utility is the resistance to water in the form of liquid and vapor. Since water is present in most applications, a task of the formulator is to choose the most water resistant components available consistent with cost and processing requirements. The functions of a polymeric binder are to encapsulate and localize pigment particles, to provide an adhering interface at the substrate to be coated, and to form a coherent film which will resist water penetration. In this way structural and adhesive strength can be maintained while the substrate is protected. Since the binder is a major part of most coatings, current research in emulsion polymer design is aimed at providing more effective barrier properties by minimizing hydrophilic components and increasing the hydrophobic nature of the polymers produced. The availability of long-chain branched vinyl esters provides the polymer designer with new choices of raw materials with which to accomplish this task. Not only do these monomers react favorably with vinyl acetate (VAc) but they also react with acrylic monomers. This versatility provides the means of tailoring polymer properties to fit a variety of applications including interior and exterior paints, clear and pigmented wood coatings, corrosion resistant metal coatings, and stable coatings and additives for cement and concrete.