Polyurea, a 100% organic compound that can be used as a wear- or waterproofing coating, is gaining rapid market acceptance, owing to its application techniques and composition, says chemicals company a.b.e. Construction Chemicals.
The polyurea available from a.b.e. Construction Chemicals is manufactured by Germany-based surface protection systems company Voelkel Industrie Produkte (VIP).
The company started importing VIP polyurea into South Africa in 2013, with a dedicated department having been initiated to deal exclusively with the product in July 2013.
However, polyurea has been available from other sources in South Africa as early as 2006.
VIP Polyurea Systems divisional manager Noel Abendroth says the compound is a spray-on elastomer, describing it as a “protection technology” coating.
He adds that polyurea can be compared with polyurethane, which is widely used for the rubber-lining of bakkie loading areas; however, polyurea has better physical properties and is stronger.
Other advantages include its fast-drying ability in as little as eight seconds, with its spray-on ability onto appropriately prepared surfaces leading to a seamless application (unlike other waterproofing technologies), thereby ensuring longevity and watertight sealing properties. This also prevents any tendencies of the compound peeling away at the seams.
Abendroth notes that an alternative method to line a tank is to glue rubber lining patches together to the inside of the tank, but the glue takes about seven days to cure before the tank can be used. However, the same tank can be back in production within 24 hrs using polyurea, he states.
Another advantage is that poly-urea will combust, but not promote the acceleration of a fire. Once the flame is extinguished, the polyurea will cease to combust. Polyurea systems are inert once cured and are solvent-free with no volatile organic compounds. Also, toxic smoke is not released when the compound burns.
How It Works
Polyurea consists of two compounds that are mixed and heated in the spraying system, which is available in high- and low-pressure systems.
Heating the two components is required to alter the viscosity of the compound and spray it in uniform flow onto a prepared surface. The hose of the spraying systems is also heated to ensure the polyurea does not cool down and solidify in the hose and cause blockages.
Meanwhile, VIP is the only company that has developed technology to apply polyurea in a cold process, suitable for small-scale waterproofing applications.
Abendroth says the application of polyurea requires specialised techniques. “The product is very unforgiving – the operator gets only one chance to do it correctly; therefore, a.b.e. Construction Chemicals specifies that only its certified and approved applicators can apply the product.”
The company trains polyurea equipment operators and it takes at least 18 months for applicators to perfect the process. Abendroth tells Engineering News that, to date, eight operators have been certified nationally by a.b.e. Construction Chemicals, adding that more than 140 polyurea machines are currently in use in South Africa.
The typical life span of polyurea depends on the application in which it is used. For example, in a rooftop waterproofing application, it will have a life span longer than 20 years, he says, adding that chemical applications range from 5 years to 20 years or even longer, depending on the corrosiveness of the chemical.
He says an example of polyurea’s robustness is evident in its application in a cement-mixing truck, where it was applied to a thickness of 2 mm to the discharge chute of the mixer: “When the truck was eventually decommissioned, it had more than of 104 m3 of concrete passing over it and the polyurea coating had not yet worn out.”
To apply polyurea successfully requires a firm and clean substrate for it to adhere to, advises Abendroth. “Any coating is only as good as the quality of the surface it is applied to and, therefore, it is of utmost importance to obtain the best possible substrate onto which polyurea can be applied from the outset.”