How an Elastomeric Coating Works

April 3, 2015

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Among the most important and useful additions to an industrial setting is the addition of an elastomeric coating to various surfaces in order to ensure higher protection and a longer life than other types of protectant that might be out there. The physics and chemistry behind them address a number of problems, not the least being thermal expansion. They can extend the life of complex or expensive items, not to mention decks and even the building itself.

Understanding the Elastomeric Coating

In order to understand the benefits of an elastomeric coating, it’s important to understand exactly what it is.

An elastomer is a polymer with viscoelasticity. What that means is that it is a form of plastic that has both viscosity, which is the ability to deform under stress, and elasticity, which is the ability to return to its original shape. In terms of viscosity, it’s easy to think of highly viscous liquids like honey, which flow rather thickly but eventually collapse under their own weight. An elastomeric coating is designed to deform under pressure in a similar fashion, but then spring back like rubber when the pressure is no longer present.

Take an outdoor electrical transformer as an example. Imagine that it is inside a metal casing. Like most things, when the casing is exposed to heat – such as the sun on a hot, California summer day – the molecules inside become excited from the energy being added to them. The additional energy from the heat causes the electrons of the atoms making up the material to move to higher energy levels, spreading those atoms out and causing the matter in question, in this case a metal casing for a power transformer, to increase in volume.

Since this is an outdoor transformer, it should be coated with some substance to protect it from the sun, rain, and other elements, and to avoid rust and other damage. This is where the problem generally appears.

Regular coatings are also subject to thermal expansion, but they may not react at the same rate or to the same extent as the metal beneath. As a result, the casing expands faster than the coating and can cause it to crack and split, opening the actual surface to the air and increasing the risk of damage. An elastomeric coating, since it possesses viscoelasticity, is able to deform around the metal casing without cracking, then return to its original shape when the weather cools at night and the case returns to its original volume.

If this sounds a lot like a thin rubber coating, in many ways it is. “Elastic polymer,” where the term comes from, is often used interchangeably with “rubber,” though the latter is more properly a reference to vulcanisates, which are polymers that have had sulfur added to them in order to improve their durability in certain situations.

Where an Elastomeric Coating is Useful

There are a number of excellent uses for this type of coating, and the industrial painting industry often employs it due to the increased safety and durability it grants a particular area or item. For example, it’s not uncommon to see facilities with an elastomeric roof coating. Using this type of coating serves a number of purposes, and can go a long way to ensuring the continued life and viability of a given building.

An elastomeric roof coating creates a solid membrane with the viscoelastic qualities mentioned above. Considering that the roof is going to be most exposed to temperature changes that can result in thermal expansion as well as being consistently at the whim of weather in general, it’s important to protect it as well as possible.

There are a few points that should be addressed, however. When installing elastomeric roof coatings over existing shingles, it is crucial to understand exactly what should be done. Professionals don’t recommend this, since it can reduce the ability of shingles to dry properly after rain or condensation, and force water to collect underneath them.

However, such a coating can reduce damage from sun and water to the extent that properly applied coatings might add up to 25 years to the service life of a roof under ideal circumstances.

It should also be noted that roof coatings are not deck coatings. They are not meant to bear the load of traffic, and should not be used in heavy traffic areas, even if that happens to be a roof.

An elastomeric deck coating is specifically traffic bearing. What that means is that it is designed to be able to remain in place and not wear away or become damaged by the normal application of regular traffic over it, be that foot or vehicle. Much like other applications of elastomeric coating, the use of elastomeric deck coating is to ensure that changes in the stress level on the coating itself do not cause cracks to form and put decks at risk.

These are often used on platforms that are at least partially outside, such as loading docks or the pathways between buildings. In many cases, an elastomeric deck coating can also be used to add traction to a floor or protect against accidents that might otherwise damage it, though that is not always the case. A lot of industrial painting work is for installation of deck coating in an attempt to prevent future problems.

Increasing Use in Industry

According to a 10 year research study done by Dow Chemical Corporation, the use of proper roof coatings can reduce the need for air conditioning by 25 percent. Furthermore, elastomeric coatings have a demonstrably longer lifespan than other coatings that do not have viscoelastic properties.

These solutions are finding a greater purchase in the industrial sector as more and more companies are discovering the savings that an elastomeric coating used properly can create.

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