You can't rub out this paint

THE milky latex of thorny succulents, found in abundance in semi-arid regions, can yield paints, adhesives, and corrosion- and moisture-resistant coatings, reveal scientists at the Delhi-based Shriram Institute of Industrial Research (SIIR). They say that they are in the process of setting up a pilot plant to process about 50 litres of latex per day, to produce low-cost commercial products like emulsion paint, water-resistant coatings for mud houses in rural areas, and jute and latex composites for making roofs.

Under a project sponsored by the Development and Promotion of Rural Technology division of the Delhi-based National Research Development Corporation, SIIR scientists are upscaling technologies that they have developed over the last few years. Paints and adhesives available in the market use expensive petroleum-based resins. Says SIIR's D A Dabholkar, "Latex could provide a low cost alternative to these petroleum-based products."

Plants belonging to the family Euphorbiaceae that yield the milky latex grow wild in the arid and semi-arid regions of Maharashtra, Madhya Pradesh and Rajasthan. Shunned even by cattle as fodder, these plants have few takers.

The scientists are using latex extracted from 3 species of the Euphorbiaceae family -- E nivulia, E neriifolia and E royleana. The latex is collected from the plants by tapping, a method akin to the one used in rubber plantations. Incisions are made on the bark and the latex is collected in small containers. This is preserved in formalin and the various constituents of the latex are later separated in the laboratory.

According to Dabholkar, the latex-based emulsion paints produced by his group conform to ISI specifications, but are cheaper than the synthetic emulsion paints. He estimates that while a litre of acrylic emulsion paint works out to some Rs 90 per litre, the latex-based substitute is likely to cost around Rs 15 per litre.

Given the economics, Dabholkar is confident that these plants can even be cultivated as cash crops, and the technology to produce latex-based products soon transferred to the rural areas.