HOW DID WE GET THIS FAR?

In past years a great many types of Polyurea were placed on the market, elastomers and coatings, some of which were true polyureas, while others were improperly called such.

The “Polyurea” system and its technology, in fact, has unique and important characteristics. However, the emphasis on the new product has hidden its certain advantages. In industry elastomeric Polyurea has been advertised as a new miracle. For many manufacturers the Polyurea system is a new area. For many companies that have already been produced elastomers for a decade, in fact, including Futura coatings, the Polyurea technique is the main component of their products that are solvent free and which gel quickly. In other words, until now, many manufacturers have not differentiated their products between those based on Texaco amines (polyurea components) and those with a polyester/polyether hydroxyl base (polyurethane components).  Both were called “polyurethanes”. In recent years manufacturers have started to distinguish between products made with different resins, i.e. those with a Polyurea base and those with a Polyol base. Many manufacturers have also described Polyurea as a miraculous product, the solution to all problems. This means that we must get rid of all doubts and intervene enthusiastically with instruments that allow us to establish when the best choice for an application must be Polyurethane or Polyurea.

THE KLEENEX EFFECT

So why is it that the term Polyurea can indicate a product so confusedly? It’s simple. What happens can be compared to what happens with the use of the name Kleenex. When you ask for a “Kleenex”, do you always specifically mean a Kleenex or just a paper handkerchief? In the same way, many users ask for a Polyurea, but do they really specifically want a Polyurea? Or do they want a product that gels quickly, without solvents and at a low temperature, and which is soft and flexible with high quality characteristics? Both systems, Polyurethane and Polyurea, correspond to this description. For decades the two products followed parallel paths, at times one of them moving ahead, at times the other. But the two products have specific uses in which the features of each can excel. Without favouring one over the other, there is always a specific product for each specific application. One product or technology alone cannot be used every time as the solution for all uses. For that matter, this is why hundreds of manufacturers develop different systems and products. Furthermore, an attentive manufacturer will always take the time to advise which is better for an application, Polyurethane or Polyurea, to get the best results. If a “miracle product” is recommended as the solution for all cases, be careful! You will run up against problems.

THE CHEMISTRY OF POLYUREA

There are very important differences and similarities between the chemistry of Polyurea and that of Polyurethane.  The first thing to note is that both systems can use the same (or similar) component “A” (ISO). Therefore, the main differences are in the “B” component of the system. The “B” component of the Polyurethane system can include various polyols (polyether, polyester) and normally requires a catalyser for fast gelling. One advantage of the Polyurethane system is that the catalyser can be dosed to control the reaction according to the application. Some applications require a smooth finish, but if the system gels too fast an “orange peel” surface will result. Furthermore, in many applications, the material has to penetrate in corners or cracks and therefore slower gelling is required. In such applications, a Polyurethane is usually chosen, so that gelling time can be controlled by means of the catalyser. The catalyser can be dosed to obtain a very fast reaction, just a few seconds, also at low temperatures.

The Polyurea systems features “polyether-amine” or “amine-compound” polyols. This polymeric systems is highly reactive and requires no catalyser. (It is a self-catalysing polymer.) The reaction is normally fast (between 5 and 15 seconds) and gels well even on cold surfaces. The reaction is so fast that the Polyurea is normally indifferent to humidity and does not react in a humid environment or if there is water on the surface. One inconvenience of Polyurea is that the reaction may be too fast for certain applications that require a smooth surface, or which require a longer reaction time.