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DATA No : WWA4201 INFORMANT : Ken-ichi Tomita

NAME : Microcrystalline wax

COMMON NAME: Microcrystalline wax
(Ref. 0021) / (Ref. 0024) / (Ref. 0057) / (Ref. 0058) / (Ref. 0091)
FORMULA: Mixture MOL.WT (average) :
Microcrystalline wax is highly viscous, it has good extensibility, does not become brittle at low temperature, has very fine microcrystals, a high melting point and shows excellent adhesion, particularly when it is heated. When mixed with other waxes, it inhibits crystal growth and if it is mixed with liquid oils, sweating is prevented. In view of these and oter excellent characteristics, it is widely used as an oily ingredient for cosmetics ( creams, lipsticks, etc. ). As mentioned as a damp proofing material for military supplies and is widely used today in paper products, for example in waterproof and damp proof paper, laminated paper, packaging paper and oil and grease proof paper. Afterward, various research on microcrystalline wax has produced application in such areas as the rubber industry, electrical insulation materials, polishing waxes, printing ink and paints, waterproofing textiles and heat adhesives.
In the future we can expect a vast range of new applications be developed. (Ref. 0021)
MELTING POINT:Melting point 60-85degC (Ref. 0021) (Method 2) (Ref. 0001)





Microcrystalline wax occurs as a mass of white to light yellow, somewhat transparent or opaque, flexible or brittle, microcrystalline plate, flakes or small hemispheres. It has a faint, characteristic odor and no taste.The composition of microcrystalline wax varies depending on the type of crude oil, raw material and method of production.The color depends on the extent of refining and ranges from white through brown to black but the raw material used in cosmwtics ranges from white to pale yellow and is transparent or opaque. It is made into thick sheets of around 5 kg in weght or thin sheets and wound around rolls and may also be made into small spheres or flakes depending on the purpose and application. Tere are many diferent types of microcrystalline wax which vary from a soft, elastic material to a hard,brittle material depending on the oil content and the amount of paraffin in it. The crystals are extremely small and cannotbe observed with the naked eye. Continued to UV Spctra
UV SPECTRA: Microcrystalline wax is only sparingly soluble in polar solvents but very soluble in non-polar solvents at room temperature. It is extremely solble at high temperatures (150degF and above). At room temperature, it is usually insoluble in methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol and amyl alcohol. It is also insolble in isopropyl acetate, dichloroethylene, nitrobenzene, furfural and chlorex. It is very soluble in chloroform, ether, benzene, petroleum ether, carbon disulfide, gasoline, carbon tetrachloride, toluene, xylene and terpene. It is sparingly soluble in naphtha and kerosene. High melting point microcrystalline wax (e.g. 170/175) is less soluble in solvents than the low melting point variety. (Ref. 0021)

[Spectrum 0047] (Ishiwata Katsumi Shiseido Research Center 1997 )
Infrared absorption spectrum measurement operation conditions, Equipment: Fourier transform infrared spectrophotometer FTS-40 (Biorad Co., Ltd.) , Resolution: 8 cm-1, Integration factor: 64, Wave number range: 400cm-1-4000cm-1 , Sample treatment: Potassium bromide tablets or liquid film.

[Spectrum 0048] (Nishiya Hiroshi Shiseido Research Center 1993 )
12C-nuclear magnetic resonance spectrometry operation conditions, Equipment: JEOL-EX400 (Japan Electronics Co., Ltd. ), Standard substance: Tetramethylsilane (0.00 ppm ), Irradiation mode: 1H full irradiation, Measurement temperature: 40degC, Deuterium solvent: Deuterium chloroform.


[Chromatograms 0019/0020] (Nakahara Kazuyoshi Shiseido Research Center 1997 )
Gas chromatography operation conditions, Equipment: Gas chromatograph 6980 ( Hewlett Packard ), Column: ULTRA ALLOY plus-1 ( HT ) ( Frontier Laboratories Ltd. ), Internal diameter: 0.50 mm, gas chromatograph capillary column joined to a 15 m long metal tube to produce a 0.50 mm thick film of dimethyl silicone as the liquid phase, Column temperature: maintain at 60 degC for 2 minutes, then raise to 370 degC at a rate of 20 degC per minute and maintain at this temperature for 12.5 minutes, Detector: FID, 380 degC, Injection temperature: 370 degC, Injection volume: 1 ml, Carrier gas: He, 33 kpa, 10ml/min. (at 40 degC ), Splitless: purge start time 2 min., Sample solution: 1 % isopentane/ pyridine ( 9:1 ) solution or 1 % isopentane solution .
During the petroleum refining process, a large number of macromolecular solids contained in crude oil are separated out and paraffin is one of them. These substances are mainly of 2 types. One of them has a relatively low molecular weight and a crystalline wax (ordinary paraffin wax ) structure formed from simple saturatd hydrocarbons. The other is a rather complex compound called microcrystalline wax having a large molecular weight side chains. The molecular weight of microcrystalline wax is 450-1,000 and the carbon number C31 - C70 . It is composed mainly of hydrocarbons ( isoparaffins ) with a main chain and side chains but also contains small amounts of straight chain hydrocarbons ( normal paraffins) and cyclic hydrocarbons (naphthenes ).
Microcrystalline wax was first produced by Standard Oil Co. (Indiana ) in 1925 but at the time it was not very widely used. However, during the Second World war, in view of its superior damp-proof, waterproof and heat-proof qualities and excellent ductility, pliability and adhesion, very large amountswere used as a packaging material for huge consignments of weapons, foodstuffs, and other micellaneous war supplies that had to be transported to the battlefield. (Ref. 0021)
A method of manufacture
Some of the different types of microcrystalline wax made from petroleum are ozocerite, ceresin, motor oil wax, deoiled petrolatum and tank bottom wax. They arebroadly classified under the four following headings depending on their source materials: Continued to Metabolism

1) Naturally occurring waxes or those obtained from certain type of oil drilling operations2) Petrolatum: obtained through the dewaxing process during the manufacture of low fluid point lubricating oil. 3) Tank bottom wax: wax sinking to the bottom of storage tank for the purpose of separating out water, mud, asphalt, etc. during the refining of wax-containing crude oil or from crude oil. 4) Synthetic products: Depending on the raw material and purpose, various types of end-product wax can be made. The ones most often used in Japan are those made from petrolatum.
(1)Microcrystalline wax made from petrolatum
Manufacture of petrolatum
Petrolatum is produced by vacuum distillation when making lubricating oil during oil refining. Topped crude is divided into light oil, a paraffin fraction, motor oil fraction and residue oil fraction. The heavy residue oil is treated with solvents to remove unstable substances.
It is diluted with solvent and cooled until the wax is precipitated and the wax is separated by filtration or by centrifuging. Currently, on an industrial scale, centrifugation method is much used for this purpose. The wax produced in this way is crude petrolatum. Thus petrolatum is a waxy residue obtained in the dewaxing of wax-containing bright stock.
Research has been done on the separation of the wax contained in petrolatum since the 1920s and nowadays, the main 2 methods used for this purpose are the following:
a) Naphtha dilution method
Petrolatum is dissolved in hot naphtha at around 140degF and this is pumped into a cooling tank and gradually cooled to the separation temperature. Initially, the cooling rate is rather fast but during the precipitation of the wax, efforts are made to ensure that itdose not exceed 3-4deg per hour. Continued to Genetic Information
The solution is stirred during cooling and the temperature is lowered to 5-20degF depending on the nature of the raw material and the degree of deoiling required. The cooled solution is transferred to a centrifugal separator to separate the wax.
b) Method using selective solvents
This method uses non-polar and polar solvents which are miscible with each other. A mixture of oil and wax is solubilized in them and then the separation process is carried out under conditions which ensure adequate crystallization for the wax. The wax which separate out is washed with a clean mixed solvent until no oil remains. Normally, petrolatum is added to a 35% acetone (anhydrous) 65% benzene mixture (85%) at a ratio of 15%, respectively, and this is heated at 60-65degC until the mixture becomes clear. This is then cooled to 18-24degC to crystallize out the wax. Next, the wax is filtered out using a revolving leaf filter or Oliver filter to avoid breaking the crystals. As the wax still contains at least 10% oil, it is again dissolved in the mixture of solvents and deoiled by means of centrifugation or other suitable method to make the finished product.

(2) Microcrystalline wax made from tank-bottom
Sludge, dirt, moisture and foreign matter must first be removed from the tank-bottom. In some cases this is possible by simply heating with chemicals. The wax-containing substance obtained by refining the tank-bottom in this way is treated with sulfuric acid, and deasphalted with propane or by other treatment to reduce the asphalt and colored material in it. It may also be treated with fuller's earth to further improve the color. Oil is then removed by distillation until an appropriate concentration is achieved for the wax. Normally, the adjustment is done by means of the flash point and penetration. Continued to Note
The substance thus obtained is considered as the wax raw material and treated just as if it were petrolatum. It is treated mostly by solvent method to produce a high melting point wax (e.g. one with a melting point of 210degF( 99degC ) or a 220degF (104degC ) melting point wax, though the yield is low in this case.
(3) Microcrystalline wax produced from motor oil
Like the process for making wax from petrolatum, this process also uses solvents for deoiling. The crystals of this wax are normally microcrystalline in form. Though thecomposition varies in accordance with the nature of the crude oil and the method used to produce the wax, there are often a large number of straight chain paraffin and their content may be as high as 99%, so this wax is more similar to paaffin wax than petrolatum wax. (Ref. 0021)
AUTHOR:The Japanese Standards of Cosmetic Ingredients Second Edition (1985) pp522-524, YAKUJI NIPPO, LTD.
VOL: PAGE : - ()

AUTHOR:The Japanese Standards of Cosmetic Ingredients Scond Edition (Annotation) I (1984)pp1101-1105, YAKUJI NIPPO, LTD.
VOL: PAGE : - ()

AUTHOR:Tsuji, S., Tonogai, Y., Ito, Y., and Harada, M.
TITLE:General analysis of various natural waxes in cosmetics
JOURNAL:J. Soc. Cosmet. Chem. Jap.
VOL:192 PAGE : 79 -89 (1985)

AUTHOR:Hillman, D. E
TITLE:Characterization and analysis of waxes by gel permeation chromatography
JOURNAL:Anal. Chem.
VOL:438 PAGE : 1007 -1013 (1971)

AUTHOR:Hawthorne, Steven B., Miller, David J
TITLE:Analysis of commercial waxes using capillary supercritical fluid chromatography-massspectrometry
JOURNAL:J. Chromatogr.
VOL:3882 PAGE : 397 -409 (1987)

AUTHOR:Kumar p, Gupta U C
TITLE:Compositional study of FDA grade mycrocrystalline wax by mass spectrometry.
JOURNAL:Indian J. Chem. Technol
VOL:34 PAGE : 197 -200 (1996)

Last updated June 19, 2007. Copyright © 1989-2007 Japanese Conference on the Biochemistry of Lipids (JCBL). All rights reserved.