Lac is the scarlet resinous secretion of the insect Laccifer lacca.
Laccifer lacca belongs to the family of scale insects and mealy bugs Coccoidea a large family of plant sucking insects. Thousands of these tiny insects colonize branches of suitable host trees and secrete the resinous pigment. The coated branches of the host trees are then cut and harvested as sticklac.
The harvested sticklac is then crushed and sieved to remove impurities. The sieved material is then repeatedly washed to remove insect parts and other soluble material. The resulting product is known as seedlac.
Seedlac which still contains 3-5% impurities is then processed into shellac by heat treatment or solvent extraction .
Geographical distribution:
Lac production is found in Northern India, Bangladesh, Myanmar, Thailand, Laos, Vietnam and parts of China.
Host trees:
Laccifer lacca can be cultivated on either cultivated or wild host trees.
- In India the most common host trees are
- Dhak (Butea monosperma)
- Ber (Zizyphus mauritanea)
- Kusum (Schleichera oleosa)
- In Thailand the most common host trees are
- Rain tree (Samanea saman)
- Pigeon pea (Cajanus cajan)
- In China the common host trees include
Uses:
The use of lac dye goes back to ancient times. It has been used in India as a skin cosmetic and dye for wool and silk. In China it is a traditional dye for leather goods. The use of lac for dye has been supplanted by synthetic dyes.
Shellac (the refined form of lac) is used in several industrial applications
- surface coatings
- textiles
- printing
- Cosmetics and pharmaceuticals
- Adhesives
- Electrical industry