![]() The raw shellac, which contains bark shavings and lac bugs removed during scraping, is placed in canvas tubes (much like long socks) and heated over a fire. The root word lakh is a unit in the Indian numbering system for 100,000 and presumably refers to the huge numbers of insects that swarm on host trees, up to 150 per square inch (23/cm 2). The number of lac bugs required to produce 1 kilogram (2.2 lb) of shellac has variously been estimated between 50,000 and 300,000. The least-coloured shellac is produced when the insects feed on the kusum tree ( Schleichera). The insects suck the sap of the tree and excrete " sticklac" almost constantly. This insect is in the same superfamily as the insect from which cochineal is obtained. Though these tunnels are sometimes referred to as " cocoons", they are not cocoons in the entomological sense. Shellac is scraped from the bark of the trees where the female lac bug, Kerria lacca (order Hemiptera, family Kerriidae, also known as Laccifer lacca), secretes it to form a tunnel-like tube as it traverses the branches of the tree. Most European languages (except Romance ones and Greek) have borrowed the word for the substance from English or from the German equivalent Schellack. Shellac comes from shell and lac, a partial calque of French laque en écailles, 'lac in thin pieces', later gomme-laque, 'gum lac'. įrom the time shellac replaced oil and wax finishes in the 19th century, it was one of the dominant wood finishes in the western world until it was largely replaced by nitrocellulose lacquer in the 1920s and 1930s. ![]() Phonograph and 78 rpm gramophone records were made of shellac until they were replaced by vinyl long-playing records from 1948 onwards. Shellac was once used in electrical applications as it possesses good insulation qualities and seals out moisture. Shellac functions as a tough natural primer, sanding sealant, tannin-blocker, odour-blocker, stain, and high-gloss varnish. It is processed and sold as dry flakes and dissolved in alcohol to make liquid shellac, which is used as a brush-on colorant, food glaze and wood finish. ![]() Chemically, it is mainly composed of aleuritic acid, jalaric acid, shellolic acid, and other natural waxes. Shellac ( / ʃ ə ˈ l æ k/) is a resin secreted by the female lac bug on trees in the forests of India and Thailand.
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