Sigmacover DTM Coating, described as an economical direct-to-metal epoxy system that replaces tar-containing coating systems, has been introduced in the Middle East by Sigma Paints.

The company termed the new coating, developed by Sigma, as the ideal replacement designed to offer significant benefits to both applicator and plant owner.

The popular coal tar epoxy system is gradually being phased out for health and environmental reasons.

"When a new coating is introduced, the applicator often finds that it is more difficult to apply than expected. Sigmacover DTM Coating has been designed with the applicator in mind," said Sigma Paints. "It is safer for staff and the environment and of course it is ideal in applications where tar is forbidden. Its low VOC level meets most regulations."

The company said it was a particularly applicator-friendly product because it sprayed well, allowing easy control of thickness on complex structures. It cured well even in difficult conditions and did not suffer from amine blushing.

Noting that it would not be easy for long-experienced users of tar epoxies to change the habit, it said Sigmacover DTM coating was designed as an economical solution with much the same performance as coal tar epoxy and a few subtle extra advantages. The easy application combined with long-term stability of physical properties.

"Because of the excellent surface wetting, no primer is required even for immersion when cathodic protection systems are in operation. Sigma DTM Coating is normally a two-coat system applied directly to metal and, as with coal tar epoxy, skipping the prime means one coat less and a more economical application," Sigma Paints said.

While coal tar epoxy was available in black and brown only, the new Sigmacover DTM Coating is available in a small colour range allowing more attractive design options, better heat reflection and so on, said Sigma Paints.

"It has typical epoxy weathering characteristics, so where appearance in exposed situations is important, polyurethane topcoats can be used. These may be applied with no fear of tar bleeding spoiling the finish as with coal tar epoxies.

"Sigmacover DTM Coating is a compliant material. It can tolerate all normal movements in steelwork. It can also handle the normal variations in coating thickness that occur in maintenance of rather complex structures."

The change from coal tar epoxy systems has been necessitated following recent studies showing that coal tar contains harmful components that can slowly leach out into soil and groundwater forming a potential hazard for health and the environment. The use of coal tar epoxy coatings is decreasing due to legislation and in some cases company policies.

Tar was cheap and had good resistance to seawater, but there were a number of problems associated with the use of coal tar epoxies. It was not possible to topcoat them with colour stable coatings like polyurethanes because the tar tended to bleed through the topcoat. Additionally the maximum topcoating time was very short and also after long service coal tar epoxies had a tendency to shrink and eventually crack, Sigma Paints explained.

It said most alternatives for coal tar epoxy were more expensive and not always easy to apply.

Bulk purchases and large-scale manufacture in modern factories enabled Sgmacover DTM coating to be produced economically and to offer a system with the advantage of coal tar epoxies, but without the disadvantages.

Sigma Paints Saudi Arabia is the leading company in the development, production and marketing of decorative paint, protective coatings and marine coatings in the Middle East with an annual production capacity of 60,000 tonnes and a staff of 250.

In Saudi Arabia, the company is the largest in its field. It was established in 1980 with its own production, storage, research and development facilities in Dammam. Sigma's expertise is inherited from its association with Sigma Coatings Holland that was founded in 1722.

Sigma Paints is part of SigmaKalon, the result of a merger in 1999 between Sigma Coatings and Kalon. The new entity is ranked as the fifth largest paints and coatings manufacturer worldwide with a sales turnover of $2 billion and a staff of 10,000 in 50 countries.