Microcrystalline waxes are a type of

wax Waxes are a diverse class of organic compounds that are lipophilic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to give lo ...

produced by de-oiling

petrolatum Petroleum jelly, petrolatum (), white petrolatum, soft paraffin, or multi-hydrocarbon, CAS number 8009-03-8, is a semi-solid mixture of hydrocarbons (with carbon numbers mainly higher than 25), originally promoted as a Topical medication, topica ...

, as part of the

petroleum Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring un ...

refining Refining is the process of purification of a (1) substance or a (2) form. The term is usually used of a natural resource that is almost in a usable form, but which is more useful in its pure form. For instance, most types of natural petroleum w ...

process. In contrast to the more familiar

paraffin wax Paraffin wax (or petroleum wax) is a soft colorless solid derived from petroleum, coal, or oil shale that consists of a mixture of hydrocarbon molecules containing between 20 and 40 carbon atoms. It is solid at room temperature and melting poi ...

which contains mostly unbranched

alkane In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in whi ...

s, microcrystalline wax contains a higher percentage of

isoparaffin In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in whic ...

ic (branched)

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and Hydrophobe, hydrophobic; their odor is usually fain ...

s and

naphthenic In organic chemistry, the cycloalkanes (also called naphthenes, but distinct from naphthalene) are the monocyclic saturated hydrocarbons. In other words, a cycloalkane consists only of hydrogen and carbon atoms arranged in a structure containing ...

hydrocarbons. It is characterized by the fineness of its

crystals A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosc ...

in contrast to the larger crystal of paraffin wax. It consists of high

molecular weight A molecule is a group of two or more atoms that are held together by Force, attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemi ...

saturated

aliphatic In organic chemistry, hydrocarbons ( compounds composed solely of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (; G. ''aleiphar'', fat, oil). Aliphatic compounds can be saturated (in which all ...

s. It is generally darker, more

viscous Viscosity is a measure of a fluid's rate-dependent resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for example, syrup h ...

, denser, tackier and more elastic than paraffin waxes, and has a higher

and

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilib ...

. The

elastic Elastic is a word often used to describe or identify certain types of elastomer, Elastic (notion), elastic used in garments or stretch fabric, stretchable fabrics. Elastic may also refer to: Alternative name * Rubber band, ring-shaped band of rub ...

and

adhesive Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advantage ...

characteristics of microcrystalline waxes are related to the non-straight chain components which they contain. Typical microcrystalline wax

crystal structure In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat ...

is small and thin, making them more flexible than paraffin wax. It is commonly used in cosmetic formulations. Microcrystalline waxes when produced by wax refiners are typically produced to meet a number of

ASTM ASTM International, formerly known as American Society for Testing and Materials, is a standards organization that develops and publishes voluntary consensus technical international standards for a wide range of materials, products, systems and s ...

specifications. These include congeal point (ASTM D938), needle penetration (ASTM D1321), color (ASTM D6045), and viscosity (ASTM D445). Microcrystalline waxes can generally be put into two categories: "laminating" grades and "hardening" grades. The laminating grades typically have a melting point of 140–175 °F (60–80 °C) and needle penetration of 25 or above. The hardening grades will range from about 175–200 °F (80–93 °C), and have a needle penetration of 25 or below. Color in both grades can range from brown to white, depending on the degree of processing done at the refinery level. Microcrystalline waxes are derived from the refining of the heavy distillates from lubricant oil production. This by-product must then be de-oiled at a wax refinery. Depending on the end use and desired specification, the product may then have its odor removed and color removed (which typically starts as a brown or dark yellow). This is usually done by means of a filtration method or by hydro-treating the wax material.

Industries and applications

Microcrystalline wax is often used in industries such as tire and rubber, candles, adhesives, corrugated board, cosmetics, castings, and others. Refineries may use blending facilities to combine paraffin and microcrystalline waxes; this is prevalent in the tire and rubber industries. Microcrystalline waxes have considerable application in the custom making of jewelry and small sculptures. Different formulations produce waxes from those soft enough to be molded by hand to those hard enough to be carved with rotary tools. The melted wax can be cast to make multiple copies that are further carved with details. Jewelry suppliers sell wax molded into the basic forms of rings as well as details that can be heat welded together and tubes and sheets for cutting and building the wax models. Rings may be attached to a wax "tree" so that many can be cast in one pouring. A brand of microcrystalline wax,

Renaissance Wax Renaissance Wax is a brand of microcrystalline wax Polishing, polish used in Antiques restoration, antique restoration and museum conservation around the world. Commonly used to polish and conserve metal objects, it is also used on gemstones and ...

, is also used extensively in museum and conservation settings for protection and polishing of antique woods, ivory, gemstones, and metal objects. It was developed by

The British Museum The British Museum is a Museum, public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is the largest in the world. It documents the story of human cu ...

in the 1950s to replace the potentially unstable natural waxes that were previously used such as beeswax and carnauba. Microcrystalline waxes are excellent materials to use when modifying the crystalline properties of paraffin wax. The microcrystalline wax has significantly more branching of the carbon chains that are the backbone of paraffin wax. This is useful when some desired functional changes in the paraffin are needed, such as flexibility, higher melt point, and increased opacity. They are also used as slip agents in

printing ink Ink is a gel, sol, or solution that contains at least one colorant, such as a dye or pigment, and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, reed pen, or quill. ...

. Microcrystalline wax is used in such sports as

ice hockey Ice hockey (or simply hockey in North America) is a team sport played on ice skates, usually on an Ice rink, ice skating rink with Ice hockey rink, lines and markings specific to the sport. It belongs to a family of sports called hockey. Tw ...

skiing Skiing is the use of skis to glide on snow for basic transport, a recreational activity, or a competitive winter sport. Many types of competitive skiing events are recognized by the International Olympic Committee (IOC), and the International S ...

and

snowboarding Snowboarding is a recreational and competitive activity that involves descending a snow-covered surface while standing on a snowboard that is almost always attached to a rider's feet. It features in the Winter Olympic Games and Winter Paralym ...

. It is applied to the friction tape of an

ice hockey stick An ice hockey stick is a piece of equipment used in ice hockey to shoot, pass, and carry the hockey puck, puck across the ice. Ice hockey sticks are approximately 150–200 cm long, composed of a long, slender shaft with a flat extension ...

to prevent degradation of the tape due to water destroying the glue on the tape and also to increase control of the hockey puck due to the wax’s adhesive quality. It is also applied to the underside of skis and snowboards as '' glide wax'' to reduce friction and increase the gliding ability of the board, making it easier to control; stickier grades of ''kick'' or ''grip wax'' are also used on cross-country skis to allow the ski to alternately grip the snow and slip across it as the skier shifts their weight while striding. Microcrystalline wax was used in the final phases of the restoration of the

Cosmatesque Cosmatesque, or Cosmati, is a style of geometric decorative inlay stonework typical of the architecture of Medieval Italy, and especially of Rome and its surroundings. It was used most extensively for the decoration of church floors, but was also ...

pavement,

Westminster Abbey Westminster Abbey, formally titled the Collegiate Church of Saint Peter at Westminster, is an Anglican church in the City of Westminster, London, England. Since 1066, it has been the location of the coronations of 40 English and British m ...

, London.

Use in petrolatum

Microcrystalline wax is also a key component in the manufacture of

. The branched structure of the carbon chain backbone allows oil molecules to be incorporated into the crystal lattice structure. The desired properties of the petrolatum can be modified by using microcrystalline wax bases of different congeal points (ASTM D938) and needle penetration (ASTM D1321). However, key industries that utilize petrolatum, such as the personal care, cosmetic, and candle industries, have pushed for more materials that are considered "green" and based on renewable resources. As an alternative, hybrid petrolatum can be used. Hybrid petrolatum utilizes a complex mixture of vegetable oils and waxes and combines them with petroleum and micro wax-based technologies. This allows a formulator to incorporate higher percentages of renewable resources while maintaining the beneficial properties of the petrolatum.

References

External links

ASTM official website
wax tests {{E number infobox 900-909 Cosmetics chemicals Waxes Petroleum products Sculpture materials