TRUTH AND MITH OF POLYUREA

In the past five years, there's been a lot of hype on polyurea coatings and elastomers - some of it true, some of it exagerated.
Polyurea systems and technology, indeed, have many unique and outstanding properties. However, the hype over a new product has gotten the actual advantages of the product lost.
All across the industry, polyurea elastomers are being promoted as a new miracle product. First, polyurea systems may be new to some coating manufacturers but Futura has been quietly using polyurea technology for over 12 years as part of its fast set solventless polyurethane product line.
In other words, until recently, Futura did not differentiate between its products based on Texaco's polyether amines (polyurea component) or polyester/polyether hydroxyl (polyurethane urethane component) resins.
Systems based on either resin were marketed by Futura as "polyurethanes". However, in the last 5 years, Futura has begun to actively indicate which systems it has that are based on polyurea raw materials and which are based on polyol resins.
Secondly, Futura doesn't believe in miracles and would like to dispel the myths and put the "hype" in perspective by providing an accurate gauge to decide whether a polyurea or polyurethane is your best choice for an application.

THE KLEENEX EFFECT

So how has the term "polyurea" gotten so misunderstood? Simple. What is actually happening can be compared to the analogy of the name Kleenex. When you ask for a Kleenex, do you really specifically want the brand Kleenex or just a tissue? Similarly, many contractors, specifiers and fabricators are asking for a "polyurea" but do they really want specifically a polyurea or do they want a system that is fast cure, solventless, cures at low temperature, is tough, flexible and has high performance properties?
A polyurea system and a polyurethane system both fit that description.
At Futura Coatings, we've been producing polyurethanes and polyureas for decades. In that time, we've found that the polyurethane and polyurea systems each have specific areas where their properties excel. It's our position that if optimum performance is needed for an application, one product or technology can't always be used as a universal solution.
This is why Futura has developed over 100 different solventless/fast cure systems. What's more, Futura takes the time to recommend the polyurea or polyurethane which best suits the application performance criteria.

OVERVIEW OF CHEMISTRY

There are some key differences and similarities between polyurethane and polyurea when the chemistry is understood.
A general and simplified reaction of the two systems can be seen in Illustration A. The first thing to notice is that both systems can use the same or similar "A" components.
Therefore, the main properties differences are contributed by the "B" component side of the system.
The "B" component of the polyurethane system is comprised of various polyols (polyether, polyester) and normally requires a catalyst in order to cure rapidly.
An advantage of the polyurethane system requiring a catalyst is that the catalyst can be adjusted to control the reaction profile to fit the application. Some applications require a smoother finish, and if the system gels too fast, a rough orange peel surface will result.
Furthermore, some applications require the material to flow into the corners or hard-to-spray areas and need a few extra seconds before gelling.
This latitude can be accomplished with a polyurethane system choice of catalyst and concentration. The catalyst can be adjusted for a urethane to cure as fast as 10 secs and at low temperatures.
The polyurea system is comprised of polyether-amines or an amine terminated polyol. This polymer is a very reactive polymer and does not require a catalyst (it's an auto-catalytic polymer).
This reactivity is typically always fast (in the 5-15 sec range) and cures well on cold surfaces.
The reactivity is also so fast and preferential that polyureas in general are moisture insensitive and do not easily react with humidity and moist substrates.
One drawback to the speed of polyureas is that they can be too fast for certain applications that require a smooth surface or a delay time before the system gels.