ARTSM, the Association for Road Traffic Safety and Management, has issued guidance to provide a basic understanding of the characteristics of Dew-Resistant and Anti-Graffiti coatings which can be applied to road traffic signs. Click here to download the guidance.

Any coating or surface treatment of a sign can affect its optical properties. This can alter the retro-reflective properties of the sign and reduce its effectiveness.

Basic information on resistance

Hydrophilic = Dew-Resistant

Hydrophobic = Anti-Graffiti

As explained in the guidance provided by ARTSM, ‘the mechanism by which a material can become anti-dew or anti-graffiti is generally based on contact angles of water. The contact angle of droplets determines the wettability of the surface – the lower the contact angle, the more hydrophilic, while the greater the contact angle the more hydrophobic the surface.

For dew-resistant films, this means that the droplets spread out over the surface of the sign, creating an even membrane of water. By contrast, droplets on anti-graffiti surfaces “bubble” up similar to droplets on non-stick frying pans.

As such, it is not possible for a material to be both dew resistant and anti-graffiti.’

Protective Overlays from Rennicks

In the following video, our Group Technical Manager, Sean Coffey, demonstrates the properties of our two specialised overlaminates – Nikkalite Dewtect, and Nikkalite Anti-Graffiti Protective Overlay.

Nikkalite Dewtect Dew Resistant Sheeting consists of a standard overlaminate coated with a specially formulated hydrophilic layer. This layer is receptive to water droplets such that in dew conditions or in rain, the droplets spread out over the surface of the sign to form an even membrane of water. This membrane has the effect of optimising sign visibility even in the worst weather.

Click here for more information on our Dewtect Dew Resistant Sheeting.

Nikkalite Anti-Graffiti Protective Overlay Film is designed to have a hydrophobic Teflon like effect with the additional fluoride compounds which enhance its durability and resilience. It is extremely difficult for any adhesive or ink to form a bond with the surface. This means posters, flyers, graffiti sprays and permanent markers can all be easily removed, which is especially useful in urban areas where advertising flyers and stickers are prevalent.

Click here for more information on our Anti-Graffiti Protective Overlay Film.

Rennicks Dewtect and Anti-Graffiti are the gold standard overlaminates for their respective applications. Rennicks has provided these to UK customers for over 20 years, which is why they’re the most trusted overlaminates on the market today. For more information on our Nikkalite specialised overlaminates, please contact us on 01928 579 966.