Shellac is an insect resin secreted by the Lac bug, a very small red parasitic bug that attaches itself to a small variety of trees in India and Southeast Asia. The insect feeds on the sap of the tree and secretes the Lac as a protective shell in which the female lay their eggs.
Once the Lac is removed from the branches, it is crushed and washed with water to remove a once valuable red or bright orange dyestuff from it. It is then heated and forced through a sieve to extract the filtered resin. It is now gathered and rolled while it is still soft and pliable and stretched into long, thin sheets. The stretched-out sheets are allowed to cool and are broken into flakes. This flake form allows fresh quality shellac to be prepared and avoid waste. The flakes are mixed with denatured alcohol to produce a liquid solution that can be applied with a paintbrush.
Shellac's uses in different Industries
Pharmaceutical -
Shellac is used to coat enteric pills so that they do not dissolve in the stomach, but in the lower intestine, which alleviates upset stomachs.
Confectionery -
Shellac is approved by the FDA as a food safe coating. Solvents must be pure ethanol (not denatured). One common use is in protective candy coatings or glazes on candies like Reese's Pieces, because of its unique ability to provide a high gloss in relatively thin coatings, even M&M's. This Non-toxic glaze is also used for fruit, coffee beans, and nuts.
Leather & Hats -
Shellac is used to stiffen felt used to make hats. It allows the makers to shape the felt into brims, bowl shapes, etc.
There are thousands of uses for shellac, some you'd never think of. Examples include: Manufacture of grinding wheels, acting as an adhesive that breaks down at low heat allowing the appraise wheels to slowly dissolve and self-clean. Early electrical insulators employed shellac as a glue, it bonds glass and metal surprisingly well.
Shellac is used as a dye, previously in fabric, and to this day in oriental carpets. It is a component in rubber compounds, as a sealing wax, component in gasket cement, as a mould for dental plates, as printing ink. It is even found in cosmetics such as hair lacquer. Even the finish on playing cards often contains shellac.
