The Problem with the Primers
As with any other coating system, surface prep is critical. This is especially true for the porous, non-uniform surface of wood. Many of the primers and intermediate coats used on wood flooring today are acrylic or polyurethane dispersions. Often times these dispersions must be stabilized by surfactants or amines. These additives can react with acidic extractable materials present in many wood species and cause discoloration. In addition the latex particle size of many interior floor primers is on the order of 100-1000 nm in diameter. These particles are too large to penetrate the surface of the wood. The lack of penetration into the surface of the wood leads to poor colored stain acceptance and non-uniform grain and pore image. In order to improve upon the appearance aspects that are most important to the consumer, primers should be formulated with binders that are near neutral pH and have a small enough particle size to penetrate the porous surface of the wood floor.
Enhancing Wood with Eastek™ Eastek™ Polymer Dispersions
are the ideal solution to the primer problems listed above. This line of sulfopolyester dispersions from Eastman have two key features that make them a perfect binder for primers used on wood floors; neutral pH and exceptionally small particle size. These key features can further be explained by an understanding of how the sulfopolyester is dispersed and stabilized in water.
The dispersed sulfopolyester in Eastek™ Polymer Dispersions is electrostatically stabilized without the need for amine neutralizing additives or surfactants. As a result, the viscosity of primers and coatings formulated with Eastek™ are independent of pH and adjustments to viscosity during application are not necessary. In addition, reactions with acid materials that are naturally present in wood that may cause color change are reduced.
Eastek™ Viscosity over Varying pH
Small Particle Size
The sulfopolyester polymers particles in Eastek™ Polymer Dispersions have an average particle size of 20 nm. This small particle size is ideal for penetrating the surface of wood flooring. The improved penetration ensures uniform color and stain acceptance as well as better crosscut adhesion. In addition, floor primers and coatings formulated with Eastek™ are nearly transparent. Unlike high solid acrylic dispersions that are opaque and milky during application, Eastek™ based floor primers are nearly translucent upon application and allow the applicator to instantly observe the wetting and appearance of the surface. This ensures fewer overlap areas and visible lap marks on the floor.
Comparison to Other Waterborne Polymers
Formulating with Eastek™
Formulating floor primers with Eastek™ is relatively straight forward. Because the sulfopolyester polymers in Eastek are electrostatically stabilized there is no need for stabilizing additives and surfactants. Eastek™ dispersions range from 30-33% solids and can be easily diluted by adding deionized water. Formulations based on Eastek™ can be tinted using conventional pigment dispersions for wood. Most Eastek™ products will form films without the use of a coalescent. In higher Tg grades like Eastek™ 1200, butyl glycol can be added as a coalescent if necessary.
Summary and Conclusion
The unique characteristics of Eastek™ Polymer Dispersions are an ideal binder for waterborne wood floor primers that provide value to all partners in the value chain. The formulator and coating manufacturer is able to reduce the additive package and formulate a amine and surfactant free primer that wets out well on porous surfaces. The professional craftsman will enjoy working with a water-based primer that shows immediate results, dries well with no grain raise, and leaves harmonic poor image due to the clarity of the primer. Finally the owner of the floor gets to enjoy a wear resistant floor that will not fade or change color over time. Contact us to request your sample of Eastek™ today to test the difference for yourself.