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Truly eco-friendly paints

The 100 per cent solids coatings use a combination of nanoparticles combined with microparticles.

CONVENTIONAL PAINT is composed of a solid portion (resin, fillers, pigments, curing agents and performance additives) and a liquid carrier. Most paints are in the range of 25-30 per cent solids and have a carrier content of 70-75 per cent.

A carrier may be either a volatile organic solvent or water. If water is used as the carrier, additional components such as ammonia may be used to keep the resin and other additives in suspension.

Eliminating carrier

Eliminating the use of a carrier is important for many reasons. When carriers evaporate during curing, they can leave tiny pinholes that promote corrosion.

The ammonia used in water borne paint is corrosive and promotes flash-rusting. Volatile organic compounds used as carriers are neurotoxic, carcinogenic and flammable. Handling, transporting and finally getting rid of them without causing environmental damage is an expensive process.

Now, Ecology Coatings, a privately held company based in Akron, Ohio, U.S., has come out with path-breaking eco-friendly paint formulations which are comprised of 100 per cent solid material, use no carriers but which are fluid enough to be easily sprayed.

These coatings are composed of oligomers (which flow better than resins) and reactive diluents, as well as pigments, fillers, curing agents, and additives. Reactive diluents, also known as monomers, lower the viscosity of the coating enough for application.

The secret of Ecology's paints is nano-engineering. The 100 per cent solids coatings use a combination of nanoparticles combined with microparticles. Such an arrangement packs space very densely, resulting in superior hardness and water resistance. Ecology's coatings have excellent adhesion and abrasion resistance.

Enhancing hiding power

Nanoparticles greatly enhance hiding power. While other companies sell tinted coatings that must be applied at 4 mils to obtain full coverage of a substrate, Ecology's pigmented coatings are truly opaque and coverage is achieved with as little as 0.3mil. Ecology's coatings require only UV light to cure. During the cure, instead of evaporating, monomers become an integral part of the final cured coating.

All of the applied coating remains after the curing process. If a user wants a 1mil dry film thickness he will only apply and cure 1mil of coating. Whereas in case of conventional paint with 25 per cent solids, the user will have to apply and cure 4mil of coating to get a 1mil dry film thickness.

Advantage ecology

Compared to conventional paints, the use of Ecology's paint technology reduces the finishing process from 20 minutes to three seconds, cuts down manufacturing line space by 80 per cent and energy consumption by 75 per cent.

Thus, although the price of Ecology's paints is higher than conventional paints, in the net term, they can yield a 20 per cent cost saving to the user. This does not take into account the better deal to the general public in terms of less harm to the environment.

Besides coatings for metal substrates, which have proved very popular with the automobile industry, Ecology has successfully developed some unique products for other applications such as a flexible, urethane based coating used to bond metal and plastic parts for use on a major medical device manufacturer's heart catheters.

Under development are coatings to produce surfaces resistant to microbial growth and a coating to `print' connections in electronic circuit boards. For plastic surfaces,

Ecology has produced hard coats that have excellent adhesion to TPO, ABS and even plated ABS without use of a primer and show enhanced abrasion and weathering resistance and cosmetic appearance.

Just two spray-able coats

Ecology's coatings for wood easily fill and seal pores, do not raise the grain and resist common stains as well as abrasion and impact. A first class finish is possible in just two sprayable coats, compared to ten coats of conventional wood paint.

A break-through white primer that is applied to wood without raising the grain and can be applied and cured at 1,000 feet perminute has also been developed.

N.N. Sachitanand

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