Vapour Permeation Barrier

Vapour permeability control is key in reducing access of corrosive materials to vulnerable substrate surfaces. While all organic resin based systems have some degree of permeability to moisture vapour, this can be significantly reduced by the use of glassflake. Glassflake has a natural leafing behaviour in an applied coating film, causing it to naturally lie parallel to the substrate surface. This stacking and overlapping of high aspect ratio flakes creates an incomplete barrier of impermeable glass in the coating, creating a 'tortuous’ path around each of the flakes of any permeating vapour to travel to the substrate.

Key Areas of Glassflake Barrier Application

  • Floor sealer coating to control escaping moisture from green concrete
  • Tank linings to prevent permeation of harsh chemicals in storage or processing
  • Desalination pump and pipe coatings to reduce permeation of salt ions
  • Flexible packaging films to slow transmission of oxygen to extend food storage times
  • Non-stick cookware coatings to reduce ingress of oils and staining molecules

With the availability of thinner grades of glassflake, produced by the spun method of manufacture, a greater number of glassflake layers are formed within the film, increasing the length of the tortuous path. With this the rate of permeation can be reduced further, often by an order of magnitude, if not greater, while often requiring a lower loading level of glassflake. The use of thinner flake also allows the retention of a high aspect ratio flake, even when there is a requirement to significantly reduce the particle diameter, for example with a thin film coating.