B A C K

WHAT MAKES A QUALITY WOOD STAIN AND WHY DOES IT MATTER?

Manufacturers of pressure treated lumber products, like any manufacturer, face the challenge of continuous product improvement in order to stay competitive. Besides competition from other pressure treating companies, there is growing competition from non-wood products with substantial marketing support aimed at consumers. As always, the challenge requires solutions that are eco-friendly as well as affordable.

With their established expertise in waterborne coatings technology, Eco Chemical™ entered the market over twenty years ago with the unprecedented offer of a stain that was compatible with preservative chemicals, while being able to deliver the critical benefits of UV color fade resistance, low VOCs, flexibility, breathability, durability, and easy cleanup. Since that time, Eco Chemical has earned its position in the market as the leading supplier of wood stains to the industry in the western U.S.

Since the start, Eco Chemical has worked in cooperation with their pressure treating clients to identify and pursue opportunities for product improvement that resonated with market demand and offered greater manufacturing versatility.  Avenues of pursuit include greater overall durability, richer color, improved weather resistance, better adhesion, and quicker dry times, without sacrificing the advantage of a water-based product. This work has involved the investigation of a host of ingredient choices over the years.

The Components of a Quality Stain

Every wood stain consists of four basic ingredients: volatiles, pigments, resins, and additives. The volatile is the vehicle that carries the solids onto the substrate surface. The volatile will evaporate once the stain has been applied to the wood, allowing the stain to form a film. The role of any volatile is to eventually evaporate and re-enter the atmosphere. Being able to formulate a superior stain using water as the carrier eliminated the concern for the impact of this ingredient on air quality. By contrast, most solvent-based stains contain mineral spirits or xylene as a volatile, both of which are classified as hazardous.

A quality wood stain requires pigments composed of extremely small particles of iron oxides, ideally available in a wide array of colors – reds, yellows, browns – that can be blended to achieve a variety of finish colors, depending on the customer’s preference. Iron oxides do not fade or discolor over time when exposed to UV radiation, unlike less costly dyes or organic pigments that tend to fade more rapidly with UV exposure.

The resin component of a wood stain is the glue that binds pigments together and then binds pigments to the wood substrate. There are many different types of resins, including acrylic, epoxy and alkyd. Resin options allow for dealing with variety of substrates, and coatings performance requirements. Eco Chemical’s work has included testing and development of various resins, including renewable vegetable oil based emulsions. These resins offer a sustainable, environmentally acceptable alternative for the market.

Other quality- sensitive additives are essential to the building of a good stain, including dispersants to break pigments up into small particles and keep them separated, thickeners to keep pigments in suspension, and build finished coating thickness. Other additives are used to prevent foaming, help the stain to flow and level, and wet out the wood to enhance product penetration. Other additives are used to provide water repellency and mildew protection.

Bringing It All Together

What makes it all work? Regardless of the coating being manufactured, balance is the key – particularly in the case of the pigment/resin ratio. This ensures the coating has enough resin to bind the pigments to the surface while holding the film together. Stains manufactured for pressure-treated lumber must meet other application requirements. Often the stain is applied to wet and cold lumber, or is not given a proper amount of drying time before being re-bundled. Frequently stains must be specifically formulated to work with a specific species of wood, or modified depending on when the stain is being applied relative to the treatment process. Eco Chemical wood stains are built to work through those requirements and deliver a coating quality with the added value of being a waterborne product.

Eco Chemical continues to push the limits of available chemistry and production technologies to provide the best products for their manufacturer customers. Contact Eco Chemical today if you are interested in learning more.