shellacs

Shellac is a natural resin produced by the lac insect, primarily Kerria lacca, on host trees in parts of South Asia and Southeast Asia. The insects secrete resin that forms on the branches as sticklac or seedlac. After harvesting, the resin is washed, filtered, and refined to remove impurities, yielding flakes or bags of shellac. Variants such as dewaxed or bleached shellac are common for different applications.

Chemically, shellac is a complex mixture of polyesters derived from aleuritic acid and shellac acids. It dissolves in alcohols (such as ethanol or isopropanol) and is largely insoluble in water. When dissolved and dried, it forms a hard, film-forming coating. The natural color ranges from pale blonde to dark orange; dewaxed and white shellac variants are lighter and often more uniform in behavior. The wax content influences gloss, flexibility, and water resistance.

Uses of shellac are diverse. It has long been used as a wood finish and varnish, especially in traditional French polishing, where thin shellac films are built up by hand. It is also used as a glaze for candies and as a binder or coating in pharmaceuticals and tablets. In early electronics, shellac served as an electrical insulating coating for components such as capacitors.

History and context indicate that shellac rose to prominence in the 18th–19th centuries before synthetic resins became widespread. Today it remains valued for restoration work, niche industrial coatings, and certain culinary and pharmaceutical applications where a natural, biodegradable coating is desirable. Production depends on lac insects and regional forestry practices, leading to sustainability considerations.