Polyurea – The New Generation of Lining and Coating

Abstract

Few seconds setting time, superior flexibility along with high mechanical strength and moisture insensitivity are only a small portion of the characteristics of the unique technology named Polyurea. This technology is on the move around the globe and recently some intriguing projects were done also in Israel. This paper is a brief introduction of the Polyurea technology. Nearly two decades ago, a new technology was introduced to the world. It was not an innovative semi-flexible Epoxy, with a better UV stability. Nor was it a new kind of fast set Urethane, with improved chemical resistance. Rather, it was a new generation of polymers, which is free of some of the drawbacks of the old conventional coatings. It is well known, for example, that epoxies excels in chemical resistance, high mechanical strength and hardness. However, it is also known that in spite of the great advance of recent years, epoxies still tend to be brittle and crack due to thermal stress and other causes. Chalking and yellowing caused by UV exposure is another notorious characteristic of Epoxies. Urethanes on the other hand are very flexible and have excellent weatherabilty. But what about hydrolytic stability, moisture sensitivity during the application and chemical resistance issues? There is much room for improvement on this regard. Polyurea combines high mechanical strength, unusual elongation, excellent water resistance and good chemical resistance. UV stability of some Polyureas is nothing less than high quality aliphatic urethanes. Therefore, in recent years the Polyurea technology is on the move all over the world in diverse fields, such as the building, petrochemical and chemical industries, corrosion protection, flooring, water systems and wastewater treatment plants, bridges and tunnels, etc.

A review on the applications of polyurea in the construction industry

“…Polyurea linings are structurally divided into aromatic and aliphatic categories; aromatic polyurea has low resistance against the UV rays. It loses its color and gloss; therefore, it is not suitable for application in the outdoors and beauty purposes and is mostly used indoor buildings while the aliphatic type is resistant against the UV rays and is used as a complete coating; of course, it should be considered that the latter is much more expensive than the former 35 …”

“…The advancement and versatility of the applications, including high moisture tolerance—whether in terms of environment, substrate, or temperature—have been making polyurea a very suitable coating for the concrete in the construction applications such as roof repair, retaining liners (due to high abrasion resistance), membranes, parking decks, bridges, and coastal sectors 21 . It has been shown that these coatings in the concrete reduce the water absorption and improve the chemical abrasion and resistance against the cold 35 …”

“…The San Raphael Bridge in California, the USA, covering an area of 50,000 m 2 with polyurea, is an example regarding the uses of this waterproof coating on the bridges. This bridge is in contact with the seawater on many days, and polyurea has acted well in this project due to its properties, including the corrosion resistance against the seawater 35 . The use of this coating has also been considered in the parking lots.…”

Protection of Concrete Structures: Performance Analysis of Different Commercial Products and Systems

“…Traditional polymeric coatings have always been widely used in the construction sector. The main categories of polymeric coatings are epoxy resins [18][19][20], acrylics [21][22][23] and polyurethanes [24][25][26], each of them with their own strengths and weaknesses as reported in Table 1. They exert their protective ability by increasing the resistance against aqueous solutions penetration due to a barrier effect.…”

Effect of NCO/OH ratio on the physico-mechanical properties of polyurethane-polyurea hybrid spray coatings

“…Polyurethane-polyurea hybrid technology represents a major type of resins in development of the coating for different substrates including metal, concrete, wood and asphalt [1,2]. This technology is based on preparation of polyurea based on the reaction of polyurethane prepolymer with a resin blend [3][4][5][6][7]. The resin blend mad up of amine terminated polymer resin or an amine chain extender.…”