PRODUCTS

ALUMINIUM MONOSTEARATE

CAS No. : 7047-84-9
EC No. : 230-325-5

Synonyms:
Dihydroxy(stearoyloxy)aluminium; Aluminum monostearate; Dibasic aluminum stearate; Dihydroxyaluminum stearate; Dihydroxy(octadecanoato-O-)aluminium; Dihydroxy(stearato)aluminium; dihydroxyaluminium; Aluminum monostearate; 7047-84-9; Dibasic aluminum stearate; Dihydroxyaluminum stearate; dihydroxy(stearato)aluminium; Dihydroxy(stearato)aluminum; Aluminium monostearate; Aluminum, monostearate; Aluminum, dihydroxide stearate; Dihydroxyaluminium stearate, pure; EINECS 230-325-5; ALUMINUM, DIHYDROXY(STEARATO)-; CHEBI:31197; Aluminum, dihydroxy(octadecanoato-O-)-; NCGC00160596-02; Aluminum, dihydroxy(octadecanoato-kappaO)-; Aluminum monostearate [JAN]; C18H37AlO4; Aluminum dextran; Aluminum monostearate [JAN:NF]; Aluminum stearate 300; Dibasic aluminium stearate; Aluminum, dihydroxy(octadecanoato-.kappa.O)-; Aluminium Monostearate; octadecanoyloxyaluminum dihydrate; Aluminium, dihydroxide stearate; CHEMBL3185220; DTXSID9048697; dihydroxido(octadecanoato)aluminium; Aluminum monostearate (JP17/NF); LS-16475; U196; CAS-7047-84-9; D01867; Aluminum monostearate, technical, ~75% (Al), powder; dihydroxyaluminium; Aluminum monostearate; Aluminum stearate 300; Dibasic aluminium stearate; Dibasic aluminum stearate; Dihydroxyaluminum stearate; Aluminum dihydroxide stearate; Stearic acid aluminum dihydroxide salt; Aluminum monostearate (JP15/NF); Aluminum, dihydroxide stearate; Aluminum, monostearate; Dibasic aluminum stearate; Dihydroxido(octadecanoato)aluminium; Dihydroxy(stearato)aluminium; Dihydroxy(stearato)aluminum; Dihydroxyaluminium stearate, pure; octadecanoyloxyaluminum dihydrate; aluminum tristearate; octadecanoic acid aluminum salt; stearic acid aluminum salt; aluminum stearate white (AAT); stéarate d'aluminium (Fr.); Daiwax WA1; Metaspa XX; Rofob 3

Aluminium Monostearate

Aluminium monostearate is an organic compound which is a salt of stearic acid and aluminium. It has the molecular formula Al(OH)2C18H35O2. It is also referred to as dihydroxy(octadecanoato-O-)aluminium or dihydroxy(stearato)aluminium.

Aluminium monostearate is used to form gels in the packaging of pharmaceuticals, and in the preparation of colors for cosmetics. It is usually safe in commercial products, but aluminium may accumulate in the body.

Properties of Aluminium Monostearate
Chemical formula C18H37AlO4
Molar mass 344.472 g·mol−1

Antacids perform a neutralization reaction, ie. they buffer gastric acid, raising the pH to reduce acidity in the stomach. When gastric hydrochloric acid reaches the nerves in the gasitrointestinal mucosa, they signal pain to the central nervous system. This happens when these nerves are exposed, as in peptic ulcers. The gastric acid may also reach ulcers in the esophagus or the duodenum. Other mechanisms may contribute, such as the effect of aluminum ions inhibiting smooth muscle cell contraction and delaying gastric emptying. Aluminum is known to bind troponin C (a muscle protein) and to interfere with voltage-dependent calcium transport. Aluminum also binds to and inhibits the activity of mitochondrial voltage gated channels (VDAC).

Description of Aluminium Monostearate
Aluminium monostearate is a salt of stearic acid and aluminium with the molecular formula Al(OH)2C18H35O2. Also known as dihydroxyaluminium or dihydroxy(stearato)aluminium, it is used to form gels in the packaging of pharmaceuticals and in the preparation of colors for cosmetics. While considered safe for use, extensive usage may result in aluminum accumulation.

Aluminium Stearate (C54H105AlO6) exists as white powder and is an aluminum salt of stearic acid. In the pharmaceutical industry, it is used as an anticaking agent; colorant; emulsion stabilizer; and viscosity increasing agent. According to the FDA, aluminum stearate is considered safe for general or specific, limited use in food. Aluminium stearate is not classifiable as a human carcinogen (cancer-causing agent).

Description of Aluminium Monostearate
Aluminium monostearate is a salt of stearic acid and aluminium. It is used to form gels in the packaging of pharmaceuticals, and in the preparation of colors for cosmetics. Aluminum is the most abundant metal in the earth's crust and is always found combined with other elements such as oxygen, silicon, and fluorine. (5, 6, 7)

What is Aluminium Monostearate?
Aluminium monostearate (C54H105AlO6) exists as white powder and is an aluminum salt of stearic acid. In the pharmaceutical industry, it is used as an anticaking agent; colorant; emulsion stabilizer; and viscosity increasing agent. According to the FDA, Aluminium monostearate is considered safe for general or specific, limited use in food. Aluminium monostearate is not classifiable as a human carcinogen (cancer-causing agent).

Compound Type
Aluminum Compound
Household Toxin
Industrial/Workplace Toxin
Organic Compound
Organometallic
Synthetic Compound

Uses of Aluminium Monostearate
Aluminium monostearate is used to form gels in the packaging of pharmaceuticals, and in the preparation of colors for cosmetics.

Use:
Aluminium Monostearate is one of numerous organo-metallic compounds sold by American Elements under the tradename AE Organo-Metallics™ for uses requiring non-aqueous solubility such as recent solar energy and water treatment applications. Similar results can sometimes also be achieved with Nanoparticles (also see Nanotechnology and Quantum Dots) and by thin film deposition. Note American Elements additionally supplies many materials as solutions. Aluminum Monostearate is generally immediately available in most volumes. High purity, submicron and nanopowder forms may be considered. Additional technical, research and safety information is available.

Use:
Aluminium Monostearate can be used in the preparation of colors for cosmetics and for the packaging of pharmaceuticals.

Aluminium monostearate is the aluminum salt of the fatty acid, stearic acid.

Aluminium Monostearate
The Stearate salts, including Lithium Stearate, Aluminum Distearate, Aluminium monostearate, Aluminum Tristearate, Ammonium Stearate, Calcium Stearate, Magnesium Stearate, Potassium Stearate, Sodium Stearate, and Zinc Stearate are fine, white powders with a slight fatty odor. In cosmetics and personal care products, Stearate salts are used mainly in the formulation of makeup products such as eyeliner, eyeshadow, mascara, lipsticks, blushers, face powders and foundations. They are also used in fragrances, deodorants, and hair and skin care products.

Why is Aluminium Monostearate used in cosmetics and personal care products?
The Stearate salts are generally used for their lubricating properties. They also help to keep emulsions from separating into their oil and liquid components. The Stearate salts increase the thickness of the lipid (oil) portion of cosmetics and personal care products and reduce the clear or transparent appearance of finished products.

Scientific Facts of Aluminium Monostearate:
The commercial stearic acid from which the Stearate salts are manufactured is actually a mixture of monocarboxylic acids obtained from animal and/or vegetable sources.

Aluminium monostearate is an organic compound which is a salt of stearic acid and aluminium. It has the molecular formula Al(OH)2C18H35O2. It is also referred to as
dihydroxy(octadecanoato-O-)aluminium or dihydroxy(stearato)aluminium.

It is used to form gels in the packaging of pharmaceuticals, and in the preparation of colors for cosmetics. It is usually safe in commercial products, but aluminium may accumulate in the body.

Aluminium monostearate (aluminum distearate) is a white, wax-like powder (metallic soap) that dissolves in mineral spirits or hot oil. A small amount (2% or less) added to oil paint imparts a short, buttery consistency. It eliminates the separation of pigment and oil, thickens varnishes considerably. A concentrate of Aluminium monostearate and linseed oil can be prepared ahead of time and added to the paint whenever needed.

Aluminium monostearate is made via the precipitation process using high quality stearic acid and exhibits the following properties: Good gelling and thickening action, excellent water repellency, transparency and a synergistic effect with zinc stearate or calcium stearate.

The effects of metal soaps on pigments have been extensively studied. Aluminium monostearate was found to coat the surface of pigment particles and helped prevent settling as well as reducing the amount of oil needed to wet the pigment. The amount of Aluminium monostearate needed to coat pigments varied on a weight basis, but a solution of 2% by weight (weight of Aluminium monostearate/weight of oil) of Aluminium monostearate was more effective than 0.5% or 4% solutions in altering pigment surfaces (Gardner 1930). The soaps coat the surface of the pigments and by steric effects keep the particles from aggregating (Pilpel 1963), which helps to keep the particles in suspension.

With increasing amounts of Aluminium monostearate the oil pigment mixture becomes viscous, and by using an appropriate amount of Aluminium monostearate the paint can gel at a lower pigment concentration (Mayer 1965). This can be used to create a "cheaper" paint since a smaller amount of a costly pigment needs to be used. A significant advantage of using stearates is that the oil and pigment do not separate greatly over long periods of time in the paint tube. Manufacturers of artists' paints often use Aluminium monostearate in their formulations without listing it as a component on the product label.

Substituents of Aluminium monostearate
Carboxylic acid salt
Organic metal salt
Monocarboxylic acid or derivatives
Organic oxygen compound
Organic oxide
Hydrocarbon derivative
Organic salt
Organooxygen compound
Carbonyl group
Aliphatic acyclic compound

Solubility of Aluminium monostearate
Aluminium monostearate exhibits relatively high solubility in hydrocarbon solvents (such as mineral spirits) when compared to other metallic stearates. It is insoluble in water, alcohol and ether; but is readily soluble in benzene, acids and common solvents when hot.

Storage of Aluminium monostearate
Aluminium monostearate has long storage life if stored in cool and dry location.

Uses of Aluminium monostearate
It has been used as a Drier, thickener, Emulsifier, and matting agent in paints and varnishes although excess amounts produce soft, noncohesive films. Aluminium monostearate is also used to waterproof fabrics, ropes, Paper, Leather, Concrete, and Stucco. It is used as an ingredient in photographic emulsions.

Aluminium monostearate dissolves in vegetable oils on heating and if a high enough concentration of the soap is used, gelling occurs on cooling. In the usual practice of making paints, the Aluminium monostearate is ground with the pigment before the bulk of the oil is added. To prepare a concentrated solution (10% w/v), add 100 grams of Aluminium monostearate (nearly fills a half liter measuring cup without compacting) to one liter of linseed oil. Heat the oil to about 150° C. and gradually slowly adding the white powder to the hot oil with stirring. Add one part of this solution to four parts of oil by weight of oil before adding to pigments and grinding.

There are multiple types of Aluminium monostearates, generally classified as aluminum mono-, di-, and tri-stearate. They vary in terms of physical properties such as melting point, free
fatty acids, and particularly the gelling properties.

Oils with a low viscosity are best thickened by aluminum di- and tri-stearate, whilst very viscous oils from stiffer gel when combined with aluminum mono- or di-stearates.

All Aluminium monostearates are highly hydrophobic, and feature outstanding transparency and excellent adhesion to metal surfaces. Due to their water repellency, aluminum di- and tri-stearate
are used as hydrophobic agents in the building industry.

Aluminium monostearate exhibits relatively high solubility in hydrocarbon solvents (such as mineral spirits) when compared to other metallic stearates. It is insoluble in water, alcohol and ether; but is readily soluble in benzene, acids and common solvents when hot.

How to Use Aluminium monostearate
Aluminium monostearate dissolves in vegetable oils on heating and if a high enough concentration of the soap is used, gelling occurs on cooling. In the usual practice of making paints, the Aluminium monostearate is ground with the pigment before the bulk of the oil is added. To prepare a concentrated solution (10% w/v), add 100 grams of Aluminium monostearate (nearly fills a half liter measuring cup without compacting) to one liter of linseed oil. Heat the oil to about 150° C. and gradually slowly adding the white powder to the hot oil with stirring.
Add one part of this solution to four parts of oil by weight of oil before adding to pigments and grinding.

Aluminium monostearate (C54H105AlO6) exists as white powder and is an aluminum salt of stearic acid. In the pharmaceutical industry, it is used as an anticaking agent; colorant; emulsion
stabilizer; and viscosity increasing agent. According to the FDA, Aluminium monostearate is considered safe for general or specific, limited use in food. Aluminium monostearate is not
classifiable as a human carcinogen (cancer-causing agent). A hard, thermoplastic white powder prepared from Tallow and Alum. Aluminium monostearate forms gels with turpentine, Mineral spirits, and oils. It has been used as a Drier, thickener, Emulsifier, and matting agent in paints and varnishes although excess amounts produce soft, noncohesive films. Aluminium monostearate is also used to waterproof fabrics, ropes, Paper, Leather, Concrete, and Stucco. It is used as an ingredient in photographic emulsions.

Synonyms and Related Terms
aluminum tristearate; octadecanoic acid aluminum salt; stearic acid aluminum salt; Aluminium monostearate white (AAT); stéarate d'aluminium (Fr.); Daiwax WA1; Metaspa XX; Rofob 3

Other Properties
Soluble in ethanol, benzene, turpentine and mineral oils.

When Aluminium monostearate was first introduced to artists' paints specifically is not known, but it is directly mentioned in a 1942 painting materials review (Gettens and Stout 1942) and in a paper by Levison in 1949 when he wrote " ... the use of Aluminium monostearate, customary for several decades, was openly declared, .." (Levison 1949 p. 826). He also notes that this soap can be added in quantities up to 2% of the grind without perceptible dilution of pigment color.

Unlike calcium and zinc stearates that are available as 100% pure salts, the Aluminium monostearate as used in commerce is a non-stoichiometric compound. The trivalent aluminum may be united with one or two stearate anions with the balance of the charge being neutralized by hydroxyl anions (Elliott 1946; Pilpel 1971). Aqueous systems for the preparation or use of disalts seems to lead to a range of products containing varying amounts of stearate, hydroxyl, and water units (Pilpel 1963). Anhydrous systems are needed to prepare stearates higher than the di-salt. Commercial preparations of Aluminium monostearate may also contain anywhere from 2 to 7% by weight free stearic acid (Pilpel 1971; Witco 1999). Analysis by weight of two commercial specimens by the author showed free stearic acid as 2 and 3% respectively. Early preparations may also contain significant amounts of palmitate (from palmitic acid) since the commercial stearic acid used in the preparation of metal soaps was often only 90% pure. Other fatty acids (palmitic, oleic, linoleic etc.) were also present as impurities.

In a series of experiments Gardner tested the effects of metal soaps on pigments. Aluminium monostearate was found to coat the surface of pigment particles and helped prevent settling as well as reducing the amount of oil needed to wet the pigment. The amount of Aluminium monostearate needed to coat pigments varied on a weight basis, but a solution of 2% by weight (wt stearate/wt oil) Aluminium monostearate was more effective than 0.5% or 4% solutions in altering the surface (Gardner 1930). The soaps coat the surface of the pigments and by steric effects or electrical charge mechanisms keep the particles from aggregating (Pilpel 1966). This keeps the pigments in suspension.

The earliest and simplest oil paints were mixtures of pigments and drying oils. Eventually driers, resins, fillers, sometimes adulterants and suspension aids were also added. Aluminium monostearate was one of the components introduced in the 20th century. The gelling of oil solutions by aluminum soaps was known since at least the late 19th century but the use of Aluminium monostearate to alter the properties of paint did not come into use until much later. Church in 1901 mentions the use of "linoleate or oleate of alumina" to prevent the "subsidence" of vermilion in tubes (Church 1901), a comment not found in the 1890 edition (Church 1890). No further mention is made of this or similar materials until decades later even in Gardner's test protocols of 1911, the first of a series of books which would become the industry standard for paint analysis (Gardner 1911).

Aluminium monostearate has been used to help suspend pigments in oil to prevent separation, to reduce the amount of oil needed to wet the pigment, and/or to increase the body of the paint by forming a gel with the oil thereby requiring less pigment.

Research into the use of aluminum and zinc stearates as aids to grinding pigments and preventing settling or separation of pigment from vehicle (medium) resulted in a patent application in 1920 and issue of U.S. patent #1,421, 625 on July 23, 1922 to Clarence A. Ward. The Aluminium monostearate was added in a range of from 1 to 5% by weight. U.S. patent #1,428,273 describing a variation of this procedure but using unsaturated mineral oils as a vehicle and aluminum soaps (stearate, palmitate etc.) to "jellify" the oil was issued on September 5, 1922 to W. A. Collings.

A 1923 commercial painters manual, however, does not list these soaps (Kelly 1923), but by 1927 the fourth edition of Gardner's paint testing manual states: "Aluminium monostearate has been used in considerable quantities during recent years, in the paint and varnish industries." (Gardner 1927, p. 664). A British test manual of 1927, however, fails to mention Aluminium monostearate or its class of materials (Fox and Bowles 1927). So at least by the early to mid 1920's Aluminium monostearate was available for commercial use and by implication use in artists' paints.

In regard to the wetting of pigments, the small amounts of free fatty acids normally present in pressed oils helped form soaps at the pigment interface, aided dispersion, and improved settling characteristics. Alkali refined linseed with its low free acid content created settling problems which were mediated by pigments precoated with metal soaps.

Aluminium monostearate is one of numerous organo-metallic compounds sold by American Elements under the trade name AE Organo-Metallics™ for uses requiring non-aqueous solubility such as recent solar energy and water treatment applications. Similar results can sometimes also be achieved with Nanoparticles and by thin film deposition. Note American Elements additionally supplies many materials as solutions. Aluminium monostearate is generally immediately available in most volumes. High purity, submicron and nanopowder forms may be considered. Additional technical, research and safety information is available.

Aluminium monostearate is a fine, bulky, odourless and colourless powder forming a plastic mass when heated, having the properties both of organic and inorganic matter. It embraces most of the characteristics of other metallic stearates and is regarded as the most important of these. Several studies of the material have already appeared in past years.

Description
A hard, thermoplastic white powder prepared from Tallow and Alum. Aluminium monostearate forms gels with turpentine, Mineral spirits, and oils. It has been used as a Drier, thickener, Emulsifier, and matting agent in paints and varnishes although excess amounts produce soft, noncohesive films. Aluminium monostearate is also used to waterproof fabrics, ropes, Paper, Leather, Concrete, and Stucco. It is used as an ingredient in photographic emulsions.

Aluminium monostearate is a white, wax-like powder (metallic soap) that dissolves in mineral spirits or hot oil. A small amount (2% or less) added to oil paint imparts a short, buttery consistency. It eliminates the separation of pigment and oil, thickens varnishes considerably. A concentrate of Aluminium monostearate and linseed oil can be prepared ahead of time and added to the paint whenever needed.

Aluminium monostearate has long storage life if stored in cool and dry location.

How to use aluminium monostearate
Aluminium monostearate dissolves in vegetable oils on heating and if a high enough concentration of the soap is used, gelling occurs on cooling. In the usual practice of making paints, the Aluminium monostearate is ground with the pigment before the bulk of the oil is added. To prepare a concentrated solution (10% w/v), add 100 grams of Aluminium monostearate (nearly fills a half liter measuring cup without compacting) to one liter of linseed oil. Heat the oil to about 150° C. and gradually slowly adding the white powder to the hot oil with stirring. Add one part of this solution to four parts of oil by weight of oil before adding to pigments and grinding.