China wax
Chinese wax , also Pelawachs or Japan Ibotawachs called, is one from the secretion of wax shield lice derived wax .
properties
China wax is a white to slightly yellowish, hard and brittle substance that is insoluble in water. The wax consists of a mixture of esters of wax acids (C 24-28 ) and long-chain fatty alcohols with 24 to 32 carbon atoms per chain, for example the cerotic acid or the lignoceric acid ester of ceryl alcohol.
The melting point is between 80 and 84 ° C. The density is relatively high and lies between 0.95 and 0.97 g / cm 3 . China wax is almost odorless. The iodine number is 1 to 2, the acid number between 0.2 and 1.5. The saponification number is 73 to 93.
Extraction
The wax is produced by the male larva of the Chinese wax scale Ericerus pela . It is the only species of wax scale that is successfully used in commercial wax production. When the trees are infested (mostly Chinese ash Fraxinus chinensis and Ligustrum lucidum ), a layer of wax up to one centimeter thick is deposited on the branches of the infested trees in about 90 to 100 days. To obtain it, the wax is scraped off the trees and melted in a water bath. The by-product insects are used as pig feed.
The amount of wax that arises depends on the plants used, the insects used and the climatic conditions such as temperature, humidity and duration of sunshine.
Wax production using Ericerus pela has been in use in China for more than 2000 years. The first news about pela wax came to Europe from the Tyrolean Jesuit Father Martino Martini , who went to China in 1640. Production reached its peak around 1900 with 6,000 tons per year. The advance of electric light and the availability of paraffin waxes led to a decline in candle production and thus in China wax production. In the nineties, around 500 tons per year were still extracted.
use
China wax is mainly used in polishes and in candle making. In Chinese medicine, china wax is used for hoarseness, pain relief, worm infestation and nervousness. Externally it is used as a healing ointment for treating wounds.
Other uses are tablet coatings, paper coating, and waxing silk and cotton. China wax was also used in the fine arts.
Saponification
By saponification of China wax can policosanols , a mixture of long-chain aliphatic C 24 - 32 alcohols, win. These are said to have a beneficial effect on the disease of lipid metabolism and the reduction of platelet aggregation . Policosanols are not yet approved as medicinal products in Germany.
literature
- Y. Ben Dov, CJ Hodgson: World Crop Pests Soft Scale Insects. Volume 7, Part A, Elsevier, 1997, ISBN 978-0-444-89303-1 , pp. 303-321.
- Wilhelm Halden, Adolf Grün : Analysis of fats and waxes. Volume 2, Springer, 1929, ISBN 978-3-642-89318-6 , p. 578.
- Gustav Hefter: Technology of fats and oils. Volume 2, Springer, 1908, ISBN 978-3-662-02120-0 , pp. 882-887.
Web links
- Cedric Gillott: Entomology in Google Book Search.
Individual evidence
- ↑ Walther Arndt : The raw materials of the animal kingdom. Borntraeger, 1928, p. 29.
- ↑ D. Hanbury: About the China wax. In: Journal for practical chemistry . Third volume, Barth, Leipzig 1853, p. 434, limited preview in the Google book search.
- ↑ Steffes, Alexander: Mixed technique, oil and china wax on cardboard ( Memento from December 22, 2015 in the Internet Archive )