SEALANTS based on silyl terminated polyethers (MS polymers), and silylated polyurethane (Spur) are among the latest breed of systems that address the region’s requirements for high-performance sealants, according to a leading Saudi-based manufacturer and supplier of construction chemicals.
These sealants find new and a wider spectrum of applications in the fast-track construction of industrial and commercial buildings due to their superior physical properties compared to standard commercial sealants, says S M Musabbar, technical manager of CMCI.
According to Musabbar, the sealant industry has evolved in recent years to meet the technical requirements of the construction market.
“Especially in the Middle East, fast-track projects demand high-performance sealants in industrial and commercial buildings, which prompted the manufacturers to develop and outbeat each other with technological and high-performance products,” he says.
Elaborating on these sealants, he says: “MS sealants have been used for nearly two decades because of its better physical properties. However, the need for a more durable sealant has resulted in the development of Spur sealants, which have a polyurethane backbone end-capped with silane. This chemical structure has given the formulators a wider choice to design superior properties by selecting an appropriate backbone from the extensive range of urethanes.”
Another property of Spur materials which is an improvement over MS types is their chemical resistance.
Spur sealants have a very good set of properties, combining the advantages of silicone-curing technology with the mechanical advantages of a polyurethane backbone. In polyurethanes, the great advantage of silane crosslinking is moisture-curability and paintability, coupled with non-staining of concrete.
CMCI’s wide range of products includes Spur sealants such as Cemtec 40FC and the recently-introduced Cemtec 30A. These sealants, which were inherit all the positive properties of silicones and polyurethanes, while eliminating their drawbacks, according to Musabbar.
Cemtec 30A and Cemtec 40FC are single-component moisture-curing PU sealants that are isocyanate-free and user and environment-friendly. Their superior properties makes them suitable for use in precast concrete panel joints, bridge culverts, retaining wall joints and caulking of doors and window frames edges. The adhesion tensile peel strength makes them suit for sealing/caulking of any substrate be it concrete, wood, aluminium or polyvinyl chloride (PVC), he says (Table 1).
Link for Table 1:
Another advantage of Cemtec 30A and Cemtec 40FC is their fast-curing property, which ensures their paintability after full cure and negligible dirt pick-up. This apart, the excellent chemical and micro-organism-resistant characteristics and their wide temperature tolerance makes them highly suitable for use in difficult environments, Musabbar states.
The Spur technology of Cemtec 30A makes it versatile in use and ensures high durability with a better tensile recovery rate and cost-effectiveness, he adds.
The mechanical properties (Table 2) of Cemtec 30A enable its use in various applications. “The product provides long-lasting weatherability and colour stability against high ultraviolet (UV) exposure. On curing, the sealant results in a smoother surface due to its ‘bubble-free’ nature, a property that is an inherent in only a few polyurethane sealants,” says Musabbar. “Cemtec 30A meets all the fundamental parameters that the present market demands and complies with ASTM C920 standard.”
Link for Table 2:
The Cemtec range, which has been well received in the market, is manufactured in CMCI’s Dammam plant.
Apart from these sealants, CMCI’s range includes the regular polyurethanes, polysulphides, epoxies, epoxidised polyurethanes and coat tar polyurethanes.
CMCI is one of the leading manufacturers and suppliers of a wide range of construction chemicals in the Middle East. Its range includes admixture, industrial flooring, waterproofing systems, joint sealants, repair and protection, and other products designed to meet market requirements.
Link for Physical properties of Spur and MS polymer sealants Chart:
