Kerria lacca commonly known as LAC, is a species of insect in the family Kerriidae, the lac insects. It belongs to the superfamily Coccoidea, the scale insects. This species is perhaps the most commercially important lac insect as it produces a resin which can be refined into shellac and other products. It is found throughout India, South East Asia, Nepal, Burma, Bhutan and South China. Lac is a resinous substance secreted by certain glands present in the abdomen of the lac insects. The secretion of lac begins immediately after larval settlement on new and tender shoots.
This secretion appears first as a shining layer which soon gets hardened after coming in contact with the air. This forms a coating around the insect and the twig on which it is residing. As the secretion continues, the coating around one insect meets and fuses completely with the coating of another insect.
Lac has been in use in India since the Vedic period. Its earliest reference is found in the Atharva Veda. The name lac seems to be derived from the word Laksha meaning one lac in Sanskrit which is suggestive of the large number of insects that settle on young succulent shoots of host plants. The great Indian epic ‘Mahabharata’ also mentions a ‘Laksha Griha’, an inflammable house of lac, cunningly constructed by the ‘Kauravas’, for the purpose of burning their great enemy the ‘Pandavas’ alive. There is also evidence that the ancient Greek and Roman knew the use of lac.
Lac is the only commercial resin of animal origin and is a natural polymer. It is made up of hydroxy fatty acids, principally aleuritic acid (9,10,16-trihydroxyhexadecanoic acid) and hydroxy sesquiterpenic acids.
Lac extracts yield crimsons to burgundy reds to deep purples using different natural mordant combinations. The colours are warmer, softer, and more muted. It has good light and wash fastness on silk and wool as compared to cotton. Also lac is sensitive to pH. We employ the natural lac dye in powder form to produce pinks (light to dark shades), burgundy, purple etc by standardised dyeing process using different combinations of natural mordants on fibres, fabric and garments with medium to good performance properties.