Raw material Kerria lacca lives in south and south-east Asia and measures only 1/2 mm in the larva stage. The parasitic lac insect punctures the bark of the host trees and feeds on the sap which is exuded. To protect its offspring, the female insect in particular produces a secretion which forms a crust around the twigs. This resinous secretion contains all the important elements of the later shellac. Before the harvest proper, some of the twigs bearing the insects are cut off and placed on new host trees in order to increase the population. After these lac larvae have been moved, the harvest proper can begin. The most important producer countries for lac, the raw material of shellac, are India with a long tradition of cultivation and industrial processing and Thailand, which only began systematic cultivation and processing after the end of the Second World War. Manufacture Stock lac, which is a raw material for shellac manufacture, is processed to seed lac in the countries of origin. The raw material is separated from the wood, ground and washed. In this process, wood residue is largely removed from the lac and the major share of the water-soluble lac dye contained in the resin is washed out. Finally, the seed lac is dried in the sun. The seed lac is a natural raw material with excellent characteristics in harmony with the environment and the starting product for the refinement of shellac: renewable, biodegradable and physiologically safe. A variety of processes are used in the treatment of this raw material. For many generations in India, the seed lac was processed by strenuous manual labour to make shellac. The raw material is enclosed in long, tightly woven cotton tubes and carefully heated over a covered fire. The lac is pressed through the cotton, residue and contamination remains in the fabric. The workers now take hold of the cleaned lac with their hands and feet and draw it out to large "skins" which are broken into flaked shellac after they have cooled. In the corresponding industrial process, the seed lac is melted, pressed through filters at high pressure and drawn out on a winder belt to a thin film which is broken into the typical flakes after cooling. Shellac manufactured by melting filtration has a natural wax content of 3 to 5 per cent and is therefore admirably suited for the manufacture of furniture polish, wood primers, sealing compound etc. To produce a de-waxed shellac with a lighter colour, the seed lac is dissolved in alcohol, decolorised by physical means and passed through several filtration stages. In this process it is cleaned from impurities and the wax is removed. Finally, the alcohol is recovered and the shellac is rolled out to a film and broken into flakes. This process has decisive advantages over melting filtration. It is more gentle and makes it possible to produce shellac with a consistently high quality and with assured characteristics which fulfil the requirements of the industries which process the shellac further. The bleaching process which enables very light-coloured shellac to be produced contrasts with the decolorisation method by physical means. In bleaching, the seed lac is dissolved in an aqueous alkaline solution, de-waxed, filtered and then chemically bleached. After precipitation, washing and drying, a light yellow powder is obtained.