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Wax: a Lesser-known but Vital Component in Domestic and Industrial Products – CPS Talk
By Penny Carmichael, on 4 March 2013
Article by Jack Humphrey
Wax can be sourced from a number of diverse locations. The biggest single source is paraffin wax (a product of the petroleum industry) but there are a number of animal and plant based waxes, of which beeswax is the company’s specialty. A wax is a mixture of long chain hydrocarbons. Paraffin waxes are exclusively alkanes whereas beeswax is a mixture of mostly esters. If you came to the talk expecting a great deal of interesting synthetic reactions you may have left disappointed. The trick with wax is in the refining. By further filtering, washing and crystallizing you can get a purer product. The wax found in chewing gum is a lot more expensive than that found in chipboard.
Wax has a low melting temperature and low viscosity in the liquid state. It’s non-toxic and is amenable to combination with other compounds. It’s also extremely stable and there was talk of thousand-year-old egyptian candles and the wax cargo of sunken warships still being perfectly fine after long periods of time. These factors make wax an incredibly useful material.
Starting with the most obvious uses, the humble candle is a great example of wax’s useful properties. Wax provides a slow releasing fuel source as well as being easy to add colour and scent to. It was interesting, if not a tad disheartening, to learn that most modern candles are produced not by pouring molten wax into a mold but by the compression of solid paraffin particles.
Dr. Case-Green then described various consumer products that wax is used in. No talk about wax could possibly miss out one of the company’s largest customers, the attraction no-one admits to liking or even having visited: Madame Tussaud’s. Here wax is used for its ease of sculpting and the ability to change the properties at will. The hands of the waxworks are made from much harder wax than the faces in order to deter would-be souvenir hunters from breaking off the fingers. Our own UCL waxwork, Jeremy Bentham’s head, is believed to be made of pure beeswax which gives a good approximation of skin colour.
Sidestepping from Tussaud’s to the Olympics, another use of wax is found in gun lubrication. Apparently the company had a hand in a beeswax based lubricant used in the Olympics which earnt 4 gold medals (although not all for the same country, I checked) and had improved accuracy compared to previous lubricants. However it had to be modified for cold temperature use on the ski slopes as part of the biathlon – a bizarre winter time mix of skiing and rifle shooting.
The biggest use of waxes in industry is in lost wax casting. Wax can be easily carved into a model which can then be coated in ceramics. By heating this up not only does the ceramic harden but the wax can heat up and be lost from the process (hence the name), leaving an exact mold to be filled with molten metal. This method is widely used to create complicated metal parts such as jewellery or engine components. Lost wax casting is also widely used in sintering, where solid metal objects are made from powdered metal in molds. Tungsten carbide tools are made this way.The second biggest use in industry is in paper and cardboard products for wax’s shiny surface and cheapness. Industrial waxes are also found rubber and plastics to regulate viscosity and in tyres to protect from ozone damage.
Most people are probably familiar with wax as a depilatory (hair remover). As mentioned before I am personally familiar with this use as, in an act of solidarity with my girlfriend, I agreed to try home wax strips on my leg. Never again. To be technically correct, the majority of depilatory waxes are in fact softened resins (sticky materials from treesap) but unadulterated beeswax can also be used. Waxes also find their way into hair products, lip balms and lipsticks. Wax is particularly good in lipstick as it tolerates the addition of colourants so well.
Wax is also used in a lot of foods. Carnuba wax is used to glaze most sweets and some fruits. Dr. Case-Green remarked that Baby-Bel cheese is a fantastic product for a wax company due to its incomparably high wax-to-food ratio.
After a quick run through of medical applications of wax, chiefly in barrier creams and a very pure wax needed for mounting histological specimens, and an assortment of other uses, in cricket balls, surf boards and explosives the talk finished with a few choice questions. An interesting side effect of the recent campaigns against transfats in foods, Dr. Case-Green explained, is the shift of hydrogenated vegetable oils from food products to use as wax products, particularly in candles. Several academic chemists were tickled that the Company only analyses their wax with relatively simple melting point apparatus. Dr. Case-Green countered that this is all that is required when determining wax purity and that the oil industry, which is far more heavily invested in hydrocarbon analysis, doesn’t use anything more hi-tech than gas chromatography. The idea of creating synthetic beeswax was raised but it would not be possible for a wax refining company to do. It would more likely be the domain of a large chemical company who can cheaply obtain the necessary monomers.
A good question was asked on the effects of colony collapse disorder on the cost of beeswax. As it turns out the company mostly imports their wax from China and Africa, where hives are moved around less, reducing the bees’ exposure to mites and viruses. Dr. Case-Green talks at many beekeeping conferences and he remarked that it is getting harder and harder for amateurs in the UK, not only due to bee mites but also to climate change.
All in all, an interesting talk. Wax on, wax off.
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