Story at a glance:
- Anti-graffiti coatings can help to prevent harmful markings on buildings.
- Depending on the surface, different types of anti-graffiti coatings may be preferred.
- Innovations in technology are giving rise to more effective coatings.
Graffiti removal has become a costly endeavor, with the US spending more than $12 billion on annual cleanup, according to data from MCA-ALPOLIC. Aside from the financial costs, many products that are used to remove graffiti also contain harmful VOCs that can damage the environment. Pressure washers can use gallons of water trying to strip the paint, and prolonged use can damage the surface.
Anti-graffiti coatings have become an easy and dependable solution to prevent graffiti in the first place.
What is anti-graffiti coating?
Coatings are often used to maintain and protect structures or surfaces long after they’re completed. While there are many types of coatings, an anti-graffiti coating is applied upon a surface in order to prevent graffiti paint from bonding to it.
The coating creates a special, highly cross-linked film between the surface and the paint, preventing staining and allowing for a quick and easy cleanup.
Anti-graffiti coatings can be applied by either roll, brush, or spray method, depending on the product line, and are classified as either sacrificial, semi-permanent, and permanent.
Sacrificial and Semi-Permanent Anti-Graffiti Coatings
Sacrificial anti-graffiti coatings create a clear film barrier upon the surface, so if it gets vandalized the coating itself can be easily removed, absorbing the paint and leaving the below area graffiti-free. The materials used for these types of coatings are usually inexpensive and composed of waxes or polymers that form weak links with the surface, allowing them to be easily removed. Once removed they have to be reapplied again, which can cost both time and money in the long run.
Sacrificial coatings are best used on surfaces like wood because it doesn’t need to get absorbed into the material like permanent coatings do. Sacrificial coatings are also preferred for murals and other artistic surfaces because they won’t gloss over like permanent coatings which can distort the images and paint underneath.
Semi-permanent anti-graffiti coatings are high build, most often acrylic, coatings that can shed layers of itself upon each cleaning. Similar to sacrificial coatings, they must be removed but this happens over a longer period of time and can be reapplied once the coating has been completely worn away. Semi-permanent coatings are ideal for surfaces like natural stone walls and historic buildings because they can be easily cleaned using hot water or high-pressure without damaging the material underneath.
Permanent Anti-Graffiti Coatings
The most sustainable of the classes, permanent anti-graffiti coatings only have to be applied once for long-lasting protection. Once vandalized, a simple solvent is often used to clean the surface, stripping the graffiti paint clean and leaving the area below safe and clear.
Permanent anti-graffiti coatings work well on most surfaces and can be either film-forming or non-film-forming. Film-forming coatings can utilize resins from polymers like polyurethane and fluorinated hydrocarbons to create a hard, protective film over the substrate in order to prevent graffiti paint from penetrating the surface. Additionally, permanent film-forming coatings can be layered to create a gloss or matte finish.
Photo courtesy of APV Engineered Coatings
APV’s VYNGUARD line is a good example of a permanent anti-graffiti coating that creates a film barrier to prevent graffiti plasticizers from migrating into the substrate. These coatings are ideal for metal and plastic surfaces because non-film-forming coatings cannot penetrate those substrates.
The advanced chemistry behind VYNGUARD Anti-Graffiti allows surfaces to resist permanent marker, ketchup, mustard, coffee, blue jean dye, and other tough stains. It is also highly resistant to algae and fungal growth, abrasions, marring, burnishing, and UV degradation, making the finish acceptable for outdoor applications. Once cured, VYNGUARD Anti-Graffiti can accept an emboss without compromising the integrity of the finish. The gloss can be adjusted from ultra matte to high gloss depending on the desired look.
Non-film-forming coatings work to chemically modify the surface tension of the substrate, which can lower the adhesion of graffiti paint, making for a quick and easy cleanup using pressurized hot water. Silicone based coatings can create porous, hydrophobic barriers that allow the substrate to ‘breathe’ while preventing the paint from permanently staining the surface.
Nanoparticle Permanent Coatings
Nanoparticle-based anti-graffiti coatings are a new and innovative type of primary coating that’s growing in popularity. By utilizing a primary binder polymer, reactive and nonreactive silica particles are formed in groups on the surface. Hydrophobic and oleophobic ligands are grafted to the silica resulting in a coating that prevents both water-based and oil-based paints from adhering to the surface. Nanoparticle based anti-graffiti coatings allow for the most proficient protection and have become the more widely used form of pretreatment to date.
