wax

wax, substance secreted by glands on the abdomen of the bee and known commonly as beeswax; also various substances resembling beeswax. Waxes are mixtures comprising chiefly esters of monohydroxy alcohols, besides other esters and free fatty acids, free alcohols, and higher hydrocarbons. They differ from fats in that fats contain chiefly esters of glycerol. Waxes are generally harder and less greasy than fats, but like fats they are less dense than water and are soluble in alcohol and ether but not in water. Among the waxes derived from plants are carnauba wax, obtained from the leaves of a palm grown in Brazil, and candelilla wax, produced by a Mexican plant (Euphorbia antisyphilitica). Those of animal origin include wool wax, or lanolin, obtained from the surface of wool fibers and used in making certain creams, ointments, and soaps, in the processes of finishing and softening leather, and as an ingredient of some paints and varnishes; spermaceti, obtained from the sperm whale, and Chinese wax, which is deposited on certain trees in parts of Asia (especially China and India) by a species of scale insect. Mineral waxes include ozocerite and paraffin, both composed of hydrocarbons. Japan wax and bayberry (or myrtle) wax are composed chiefly of fats.

Figures modeled or molded in beeswax, either as finished pieces or for use as forms for casting metal (see lost-wax casting) or creating preliminary models. At ordinary temperatures, beeswax can be cut and molded easily, it melts at a low temperature, it mixes with any colouring matter and takes surface tints well, and its texture can be modified by a variety of additives. The ancient Egyptians used wax figures of deities in their funeral rites, and the Romans used wax images as presents in the Saturnalia. Michelangelo used wax models in making preliminary sketches for his statues. Wax medallion portraits, popular in the 16th century, enjoyed renewed popularity in the 18th century. John Flaxman made many wax portraits and relief figures which Josiah Wedgwood translated into pottery. Exhibitions of wax figures are still popular, the most famous being those of Madame Tussaud's museums in London and other international cities.

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Any of a class of pliable substances, organic compounds of animal, plant, mineral, or synthetic origin, less greasy, harder, and more brittle than fats. Waxes contain mostly compounds of high molecular weight (fatty acids, alcohols, and saturated hydrocarbons). Many melt at moderate temperatures and form hard films that can take a high polish. Animal and plant waxes are esters of fatty acids and either a sterol (see steroid) or a straight-chain higher alcohol (e.g., cetyl alcohol). Animal waxes include beeswax; wool wax (lanolin), used in pharmaceuticals and cosmetics; and sperm oil and spermaceti (from sperm whales), used as lubricants. Plant waxes include carnauba wax, candelilla wax, and sugarcane wax, used in polishes. About 90percnt of the waxes in commerce are recovered by dewaxing petroleum. There are three main types: paraffin (used in candles, crayons, paper coating, and industrial polishes and as a protective sealant, lubricant, insulating agent, and antifrothing agent), microcrystalline wax (used in paper coating), and petrolatum (used in ointments and cosmetics). Synthetic waxes (carbowaxes), derived from ethylene glycol, are commonly blended with petroleum waxes.

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Mixture of organic compounds traditionally derived from petroleum but also obtained synthetically. It usually consists of alkane hydrocarbons (also called paraffins) and is used for coating and sealing, for candles, and in floor waxes, lubricants, waterproofing agents, and cosmetics. Seealso alkane.

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Traditional method of producing molds for metal sculpture and other castings. It requires a positive, a core made of refractory material and an outer layer of wax. The positive can be produced either by direct modeling in wax over a prepared core (direct lost-wax casting), or by casting in a piece mold or flexible mold taken from a master cast. The wax positive is invested with a mold made of refractory materials and heated to melt the wax, leaving a narrow cavity between the core and the investment. Molten metal is poured into this cavity. When the metal has solidified, the investment and core are broken away. Seealso investment casting.

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Very hard wax obtained from fronds of the carnauba tree, Copernicia cerifera, a fan palm of Brazil. During the regular dry seasons in Brazil, where it is called the tree of life, the carnauba palm protects its fanlike fronds from loss of moisture by secreting a coat of carnauba wax. Carnauba has been used in high-gloss polishes, phonograph records, and explosives. Synthetics have replaced it for many applications.

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Wax has traditionally referred to a substance that is secreted by bees (beeswax) and used by them in constructing their honeycombs.

It is an imprecisely defined term generally understood to be a substance with properties similar to beeswax, namely

• plastic (malleable) at normal ambient temperatures
• a melting point above approximately 45 °C (113 °F) (which differentiates waxes from fats and oils)
• a relatively low viscosity when melted (unlike many plastics)
• insoluble in water
• hydrophobic

Waxes may be natural secretions of plants or animals, artificially produced by purification from natural petroleum or completely synthetic. In addition to beeswax, carnauba (a plant epicuticular wax) and paraffin (a petroleum wax) are commonly encountered waxes which occur naturally. Earwax is an oily substance found in the human ear. Some artificial materials such as silicone wax that exhibit similar properties are also described as wax or waxy.

Wax chemistry

Chemically, a wax is a type of lipid that may contain a wide variety of long-chain alkanes, esters, polyesters and hydroxy esters of long-chain primary alcohols and fatty acids. They are usually distinguished from fats by the lack of triglyceride esters of glycerin (propan-1,2,3-triol) and three fatty acids. In addition to the esters that contribute to the high melting point and hardness of carnauba wax, the epicuticular waxes of plants are mixtures of substituted long-chain aliphatic hydrocarbons, containing alkanes, fatty acids, primary and secondary alcohols, diols, ketones, aldehydes. Paraffin waxes are hydrocarbons, mixtures of alkanes usually in a homologous series of chain lengths.

Uses of wax

Waxes are used to impregnate and coat paper and card, to waterproof it or make it resistant to staining, or to modify its surface properties. Waxes are also used in wax polishes for furniture and other wood products, footwear and vehicles, as mold release agents in mold making, as a coating for Edam and Gouda cheeses, and to waterproof leather and fabric. Wax has been used since antiquity as a temporary, removable model in lost-wax casting of gold, silver and other materials. Waxes and hard fats such as tallow have long been use to make candles, used for lighting and decoration in a number of religious traditions, including Christianity and Hinduism. Chanukah, the Jewish Festival of Lights which centers on the lighting of candles, dates back to 165 BC. There are several Biblical references to candles, and the Emperor Constantine is reported to have called for the use of candles during an Easter service in the 4th century AD. Candles continue to be used to by Christians in worship as symbols of the light of Christ. In the Roman Catholic Church, beeswax candles are used, since a colony of bees is a celibate sisterhood with a single mother. Candles have also played a role in paganism, in Wiccan ceremonies, and in modern humanist festivals. Wax candles were also used in secular life for lighting, signals in warfare, safety in travel and for time keeping, and are still in popular use today to provide soft lighting for meals and other social activities. Wax with colored pigments added has been used as a medium in encaustic painting, and is used today in the manufacture of crayons and colored pencils. Carbon paper, used for making duplicate typewritten documents was coated with carbon black suspended in wax, typically montan wax, but has largely been superseded by photocopiers and computer printers. In another context, lipstick and mascara are blends of various fats and waxes colored with pigments, and both beeswax and lanolin are used in other cosmetics. Also, the sports of surfing, skiing, snowboarding and skateboarding often use wax to enhance the performance.

Wax types

Animal waxes

• Beeswax - produced by honey bees
• Chinese wax - produced by the scale insect Ceroplastes ceriferus
• Shellac wax - from the lac insect Kerria lacca
• Spermaceti - from the head cavities and blubber of the sperm whale
• Lanolin (wool wax) - from the sebaceous glands of sheep
• Ear wax - found in the human ear.

Vegetable waxes

• Bayberry wax - from the surface of the berries of the bayberry shrub, Myrica faya
• Candelilla wax - from the Mexican shrubs Euphorbia cerifera and E. antisyphilitica
• Carnauba wax - from the leaves of the Carnauba palm, Copernica cerifera
• Castor wax - catalytically hydrogenated castor oil
• Esparto wax - a byproduct of making paper from esparto grass, (Macrochloa tenacissima)
• Japan wax - a vegetable triglyceride (not a true wax), from the berries of Rhus and Toxicodendron species
• Jojoba oil - a replacement for spermaceti, jojoba is pressed from the seeds of the jojoba bush, Simmondsia chinensis
• Ouricury wax - from the Brazilian Feather palm, Syagrus coronata.
• Rice bran wax - obtained from rice bran (Oryza sativa)
• Soy wax - from soybean oil.

Mineral waxes

• Ceresin waxes
• Montan wax - extracted from lignite and brown coal
• Ozocerite - found in lignite beds
• Peat waxes

Petroleum waxes

• Paraffin wax - made of long-chain alkane hydrocarbons
• Microcrystalline wax - with very fine crystalline structure

Synthetic waxes

• Polyethylene waxes - based on polyethylene
• Fischer-Tropsch waxes
• Chemically modified waxes - usually esterified or saponified
• substituted amide waxes
• polymerized α-olefins

References

External links

• Waxes
• www.igiwax.com, resource for wax product research
• www.microcrystallinewax.net, resource for microcrystalline wax research