stearin
Stearin is a mixture of stearic and palmitic acid , which is obtained from the corresponding triglycerides (vegetable and animal fats and oils) by saponification and acidification of the soapy water. It is used, among other things, to make candles and soaps .
Stearin was discovered as a suitable raw material for candles in 1818 . Stearin is also used as an additive to industrial lubricants in order to increase the separability. The melting range of stearin is between 55 and 70 ° C, depending on its composition. In contrast to paraffin , which is a by-product of petroleum processing , stearin is mainly obtained from vegetable palm oil or from animal fat and is therefore biodegradable. Stearin candle scraps that only contain natural or nature-identical dyes can be composted. Stearin is sometimes used together with beeswax to make candles.
Market share
Up to now, stearin has rarely been used for making candles because paraffin is cheaper and more universally applicable. Of the 163,532 tons of candles that were sold on the German market in 2005, the share of stearin candles was 7% according to industry estimates. With rising crude oil prices, the share can therefore shift in favor of the stearin candles.
Manufacturing
Stearin candles are mostly made using a casting process. Paraffin is also often added to produce a corresponding quality of candles. Otherwise, stearin candles can be pressed, drawn and extruded like paraffin candles. Since stearin is less pliable and the candles can easily break, paraffin can be added up to a certain amount in Germany and the product can be sold as stearin candles if it contains at least 90 percent stearin.
quality
Stearin candles are stronger than paraffin candles. Compared to paraffin candles, they have the advantage of greater dimensional stability when exposed to heat. Stearin remains relatively solid up to the melting point and usually only then becomes liquid. Paraffin becomes soft at around 40 ° C, depending on its composition. Paraffin candles bend in direct sunlight, while stearin candles retain their shape. Many candles consist of a mixture of paraffin and stearin, for example in a ratio of 80% paraffin to 20% stearin. In this respect there is a connection between price and quality.
Environmental balance
Stearin is obtained 100% from vegetable or animal, and thus renewable raw materials and - in contrast to paraffin from petroleum - can ideally be considered CO 2 -neutral. However, this is not the case if natural vegetation is first removed in order to obtain vegetable oil or fat, as is very often the case with the use of palm oil, for example. In extreme cases, clearing peat forests by fire can result in up to seven times the CO 2 emissions compared to paraffin. As Organic Candles may therefore only be called tallow candles, which are made from sustainably grown raw materials. The production according to RSPO guidelines ("Round Table for Sustainable Palm Oil " - English : Roundtable on Sustainable Palm Oil - with participation of WWF ) is the only so-called sustainability seal for palm oil on the market alongside the seal for certified organic cultivation. However, the RSPO is controversial among many environmental and nature conservation organizations, among other things because palm oil companies choose and pay their certifiers themselves, because the RSPO does not include any independent reviews of the certificates and because the palm oil industry dominates the RSPO in terms of votes.
An allegedly higher pollution load when burning paraffin candles compared to stearin candles due to the formation of polycyclic aromatic hydrocarbons (PAH) or dioxins and furans has not been confirmed by studies.
About naming
In the international literature, the glycerol tristearate ( tristearin ) is indicated by stearin .
See also
Web links
Individual evidence
- ^ Dieter Neubauer: Kekulé's dreams. Springer Spectrum, 2014, ISBN 978-3-642-41709-2 , p. 100.
- ↑ Hans-Dieter Jakubke, Ruth Karcher (Ed.): Lexikon der Chemie. Spectrum Academic Publishing House, Heidelberg 2001.
- ↑ https://www.vis.bayern.de/produktsicherheit/produktgruppen/haushaltswaren/kerzen.htm
- ↑ Rettet den Regenwald eV - Palm oil topic. In: regenwald.org. Retrieved December 23, 2016 .
- ^ RSPO website
- ^ Robin Wood eV - Tropical Forests. In: robinwood.de. Retrieved December 23, 2016 .
- ↑ Bayreuth Institute for Environmental Research (Ed.): Second investigation of combustion gases in paraffin scented candles for toxicologically relevant pollutant classes. Results report . Bayreuth 1999 ( PDF ).
- ↑ VDK - Do burning candles give off harmful substances? ( Memento from November 20, 2012 in the Internet Archive )