The protective coatings market has been a major consumer of glassflake materials for many decades now. In fact, the very first glassflake produced in Leeds, UK by Glassflake Ltd was supplied to a protective coatings manufacturer for use in anti-corrosive coating materials. While the demand for glassflake in the heavy duty coatings market remains, the overall protective coatings market has developed to encompass thinner films and novel applications methods of powder coatings and aerosol. Alongside this, glassflake technology has also improved, offering thinner flake to boost barrier properties in thin film coatings and reduced diameter flakes of high aspect ratio, for direct to metal areas.
Glassflake provides an excellent barrier to moisture, this effect is used extensively to control release of moisture from green concrete to an acceptable rate. The overlapping flakes of glass form an incomplete barrier to permeation, forcing moisture to take a tortuous path through the film. Once the film is cured over the concrete, work on other areas of the project can continue without damaging the concrete. Where lower diameter flake is used, the full reinforced coating film is able to penetrate the substrate pores and afford excellent adhesion to the concrete.
For many protective coatings, the requirement to offer substrate protection is driven by the extreme locations for oil & gas extraction. Handling such materials poses very obvious and serious fire hazards, which coatings in these situations must be able to withstand. It is vital that intumescent coatings in these environments can protect steel from rising above 650⁰C to maintain structural integrity—this requirement also now becoming the norm in architectural settings. Glassflake contributes to fire performance by offering an oxygen barrier to prevent flame spread and reinforcing any surface char formed, acting as a thermal insulator.
To offer suitable protection of any substrate, there must be a significant film thickness present. While many specifications will provide an ample film at the time of application, it is important to maintain the film thickness over the full lifespan of the coating – high abrasion rates will in time leave substrate directly exposed to the harsh environments. Glassflake can provide resistance to wear over time, whether this comes from abrasive silt in seawater riser pipes through to heavy vehicle traffic on concrete coatings. This strengthening is provided by the high Mohs hardness and by mechanical reinforcement via the high surface area of the filler.