sofw journal 4 2011

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4-2011

English Edition

International Journal for Applied Science

Personal Care Detergents Specialties

E. Endlein

K.-H. Peleikis

Natural Waxes

Properties, Compositions

and Applications

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COSMETICSNATURAL WAXES

E. Endlein, K.-H. Peleikis*

Natural Waxes Properties, Compositions and Applications

General Properties of Waxes

Waxes exist in form of natural and syn-thetic substances (Fig. 1). The natural onescan be divided into renewable and non-renewable. The renewable waxes are re-growing and can be either chemicallyunmodified vegetable and animal basedor can be chemically modified like f.i.hydrogenated or re-esterified types. Thenon-renewable fossil waxes are dividedinto crude or refined montan resp. pe-troleum waxes.Synthetic waxes exist as homo-polymers(f.i. PE, PP, PAO, FT, Oxidates) and co-polymers (f.i. EAS).Due to the difficulty to find a commonchemistry for all kind of waxes it is nec-essary to come up with an accepted gen-eral definition.As such a general definition, waxes canbe defined according DGF (German So-ciety for Fat Sciences) as a mixture ofmore or less hydrophobic substances ofmedium chain length with the following

properties:

from soft and tacky to hard andplastic or breakable at 20 C

melting points from 40 to 140 C,approx.

re-solidifying unchanged aftermelting

mostly relatively low melt viscosities

sometimes buffable

strong temperature dependence of

solubility and consistence.

Real natural waxes according to our un-derstanding are re-growing, derived bybiogenesis in a sustainable process and

In general waxes are always a mixture of more or less hydrophobic or-

ganic substances of medium chain length. At 20 C plastic up to hard

and brittle, waxes will melt higher than 40 C up to 140 C without de-

composition and will re-solidify unchanged. Solubility and consistency of

waxes are strongly temperature depending.

Natural waxes are derived by biogenesis in a sustainable process and are

physically refined without any chemical transformation. Hence natural

waxes can be considered truly as natural resp. even organic (bio) in par-

ticular cases. Natural waxes show unrivaled well-balanced compositionsleading to great performances for all kind of applications and offer excep-

tional properties in diverse systems in cosmetic, pharmaceutical, food and

household consumer goods. Especially properties refer to oil gelling and

retention as well as to viscosity build-up and structuring. An array of differ-

ent sensory profiles and textures can be achieved and surface gloss can be

altered as well.

Abstract

-Fig. 1 Diversification of waxes

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will be truly natural (e.g. acc. certifica-tion standards like Ecocert). In case oforganic farming or certified wildflower

collection they are conforming to Euro-pean Directives 834/2007 resp. 2092/ 91and USDA/NOP as well as Natrue Class 1.Natural waxes show unrivalled well-bal-anced compositions leading to greatperformances for all kind of applica-tions. They offer exceptional propertiesin diverse systems in cosmetic, pharma-ceutical, food and household consumergoods.Special properties refer to oil gelling andoil retention as well as to viscosity build-

up and structuring. An array of differentsensory profiles and textures can beachieved and surface gloss can be alteredas well.Natural waxes are composed around abasic principle which is a unique mix oflong-chain, linear and even-numberedaliphatic mono-esters. Partially varyingamounts of linear hydrocarbons (can-delilla and bees wax), free wax acids(bees wax), free wax alcohols resp. poly-cosanoles (shellac and carnauba wax)and other ingredients like phytosterols,

natural resins etc. are also enclosed. Forcosmetic applications in particular berrywax and some further more exotic wax-es (myrtle, mimosa, green tea, jasmin,rose, lotus and orange blossom wax) arealso of interest.

Field of Applications

For applications the main properties ofwaxes refer to oil gelling, viscosity in-

creasing and texturing.A lot of gellifiers (hydrocolloids) for wa-ter based systems are well known but notfor oils. More or less just waxes serve thisrequired performance. Other oil gellifierslike polymers or sugar esters will formnon true crystalline gels. In mixtures ofoils and waxes a special kind of crys-talline structure is formed during solidi-fication these structured oil gels arenot real gels according a more narrowdefinition.When these structures of oil-wax-gelswill be pressed or rubbed the crystals willbreak and melt so that as a result asmooth distribution of the oil gel on f.i.skin and hair is achieved.

A lot of very specific characteristics arisefrom the usage of waxes in very differ-ent applications. Examples are the abili-

ty of

oil binding in shoe polish and lipsticks

water repellency in dragees andindustrial coatings

release performance in bakery andplastics

scratch resistance in car polish andinks

platicizing in hot-melts and chewing

gum lubrication in pencils and metal

working

dispersing in mascara and toners

retard release in agriculture andpharma matrices

binding properties in ceramic andcosmetic powders.

Characterization

For the characterization of waxes thefollowing properties are typical:

melting point (MP), often as dropmelting point

solidification as congealing point

hardness as penetration numberat 25 C

acid and saponification value(AV and SV)

iodine value (IV) and peroxide value(POV)

differential scanning calorimetry(DSC-analysis).

Using the DSC curves waxes can be clas-sified very well by their thermal proper-

ties. These graphes give an informationabout the beginning and ending of thesoftening of the material. In Fig. 2 theDSC curves of several natural waxes(Candelilla Wax/Kahlwax 2039, Beeswax/Kahlwax 8108 and Carnauba Wax/Kahl-wax 2442L) are shown.Candelilla wax (green broken line) showsa little broader but a similar curve likecarnauba wax (black unbroken line)where as candelilla wax melts somewhatlower than carnauba wax. Candelilla waxis still quite hard but much more amor-

phous when compared with carnaubawax. Hence tendency to break is less pro-nounced with candelilla wax.

-Fig. 2 DSC curves of several natural waxes

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Bees wax has a more complex meltingcurve (red dotted line). The softeningstarts already at about 35 C that means

around skin temperature. Hence beeswaxis quite soft and pliable.In contrast to beeswax the curve of car-nauba wax shows the beginning of soft-ening only at about 55 C but the ma-

jority of the composition melts even atmuch higher temperatures. Also the curveis quite narrow. Hence carnauba wax is avery hard high melting wax with a highdegree of crystallinity.

Natural Waxes

In nature waxes are effective protectorsagainst mechanical stress, water-loss, UV-radiation and parasites. The permeabili-ty for gas and water vapor of the thinwaxy films is essential for plants. Incor-porated into cosmetics or as coatings forfruits permeability is an important fac-tor as well.The biogenesis of natural waxes is a sus-tainable process.Refining of crude natural waxes is car-

ried out in a multi-stage process. At thebeginning the crude material will bemolten under steam heating and cleanedby specific filtration processes to receivea so-called pre-cleaned wax. After theaddition of different kind of refining ad-ditives the mixture is cleaned a secondtime to obtain the final fully refined wax.This process requires an in-depth know-how which will be reflected in the veryspecial quality products from Kahl WaxRefinery, Trittau (Germany) which are

offered as Kahlwax.The basic principle of the cleaning andrefining process is schematically shownin the flow chart of Fig. 3.

Shapes of waxes from the range ofKahlwaxesDepending of the processing or applica-tion Kahlwaxes can be applied in theform of pellets, prills, powders and emul-sions with different particle sizes.The emulsions typically contain particleswith mean diameters of about 100 nm.In Fig. 4 the very narrow distribution ofparticles from two typical Kahlwax emul-sions are shown.

-Fig. 3 Cleaning and refining of crude natural waxes

-Fig. 4 Typical particle distribution in Kahlwax emulsions

-Fig. 5 Prill waxes consist of beads (100-fold magnification)(Source: Fraunhofer Institut, Oberhausen, Germany)

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The prill waxes consist of perfectlyround-shaped beads with particle sizesin the micrometer range. The picture in

Fig. 5 shows a 100-fold magnification ofsuch particles.The powdery types of the Kahlwaxeshave the form of either spherical beadsor are particles with finely grained frac-ture pattern in the lower micrometerrange (Fig. 6).The renewable natural waxes can be ani-mal derived like bees wax and shellacwax or plant derived like carnauba, can-delilla, rice brain and sunflower seed waxas well as berry, fruit and flower waxes.

Natural waxes can be divided into firstand second generation. First generationwaxes are beeswax, carnauba wax andcandelilla wax.Natural waxes do not fall under REAChregistration (excempted according toREACh Annex 5).

Genesis of Natural Waxes

Carnauba wax, candelilla wax, sunflowerwax and rice bran wax are leaf and

hull waxes, resp. Examples for fruit andflower waxes are berry wax and japanwax, harvested from rhus vernicifluaandrhus succedanea trees in Asia, and f.i.mimosa wax.Animal derived waxes are bees wax andshellac wax.

Animal Waxes Insect Waxes

Bees wax Cera alba and Cera flava

Bees wax is an exudation of the abdomi-nal glands of the honeybee. To gather

1 kg of honey, ca. 100.000 flights over240.000 km with the contact of roughly15 million blossoms by the bees (apismellifera) are necessary.From a colony with 30-70.000 bees ca.30kg honey p.a. and about 1kg wax canbe harvest.Organic bees wax (Kahlwax 8139) is ob-tained from organic honey productionunder strictly controlled and protocolledconditions.Organic bees wax is obtained mainly fromcapping wax. The product is ecocertifiedas Organic Food Additive according to EC834/2007 and USDA NOP.The main cultivated bees races are show-ing only little differences in the compo-sition of the bees waxes and contain:

approx. 70% C40-C52 esters of C24-C34 long-chain alcohols with C16-C18 fatty acids (C46, Myricylpalmi-tate dominating)

13-18% mainly C25-C35 hydrocar-bons (C27 dominating)

10-15% C24-C32 free wax acids(C26 and C30 = cerin dominating)

approx. 1% C34-C36 free waxalcohols

0.5-1% myristolacton.

Bees wax when freshly exuded is whiteand colourless but will become colouredmainly by picking up and storing pollenand honey. The crude wax is refined byan absorption technology to receivewhite Kahlwax 8104 (Fig. 7). The cosmet-ic definitions are cera flava for the yel-low grade and cera alba for the whitegrade. The INCI name is Bees wax/CeraAlba.

The properties of bees wax are:

relatively low melting point(drop melting point 61-65 C)

moderately hard and a bit sticky

plastic and kneadable at bodytemperature

-Fig. 6 Typical powdered Kahlwaxes (type P100): REM pictures with magnificationsof 250-fold (left) and 500-fold (right) (Source: Fraunhofer Institut, Oberhausen,Germany)

Fig. 7 Bees wax in crude, yellow (Cera flava) and white (Cera alba) quality

Beeswax Crude Beeswax Yellow Beeswax White

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Carnauba wax has very good emulsifica-tion properties and an excellent oil bind-ing capacity for ester oils as well as for

mineral oil. Carnauba wax raises themelting point of oil gels. Therefore it is apreferred additive in lipsticks, lipbalmsand very well suitable for mascaras. Itprovides glossy and slippy surfaces.For pharma and food applications thetypes of Kahlwax 2442L, 2442P100 and2442P5 are used as glazing agents (aloneor in combination with bees wax) and asrelease agents (as a technical aid). It isadded also to chewing gums, fruit coat-ings, bakery (wafer) coatings and retard

tablets.For applications in pharma and foodindustries carnauba wax is subject to dif-ferent regulations and monographs:Phar.Eu. and Food Directive 95/2 as E903,US-Regulations for food (FDA 21 CFR),GRAS184.1978 (Generally Recognized AsSafe) and FCC (Food Chemical Codex).Organic carnauba wax, Kahlwax 6642, isobtained by just melting and filtration ofcrude untreated carnauba wax of high-est quality. Its very light coloured andof a faint pleasant smell. It shows out-

standing oil binding properties. Kahlwax6642 is ecocertified as Organic Food Ad-ditive according to EC 834/2007 and US-DA NOP.

Candelilla wax Candelilla CeraCandelilla wax is an exudation of thewild plant euphorbia cerifera (antisiphi-litica) which is located in the northernMexican desert (Fig. 11). The wax is ob-tained from the upper earth part of the

plant. The weed is dried, boiled with wa-ter and the wax is then skimmed off bydecanting. The dark brown crude can-delilla wax is refined to a pale yellow waxto the type Kahlwax 2039 and 2039 L,resp. (Fig. 12).Candelilla wax has a remarkable hard-ness but little crystallinity. It shows sometackiness at higher temperatures. Themelting point of about 72 C is in be-tween bees and carnauba wax. The con-tent of resins and sitosterols togetherwith the esters are responsible for theexcellent oil binding for ester oils (inparticular Kahlwax 2039 L). The wax pro-vides high surface gloss when applied inlipsticks and serves sufficient contrac-

tion, important for the demoulding oflipsticks.Kahlwax 2039L is peroxide-free, givesa fully transparent melt without anyresinous residues. Kahlwax 2039L en-

hances oil binding and provides excellentsensory properties.As an additive in food and pharma it is aglazing agent for chiclets, used in chew-ing gums and in pharmaceutical tablets.It is regulated acc. Ph.Eur. and as directfood additive according to EU Regula-

tion Food-Additive (95/2) as E902 andacc. US-Regulation (FDA 21 CFR): GRAS184.1976 and FCC (Food ChemicalCodex)

Sunflower wax Helianthus AnnuusSeed CeraThe wax is obtained from Sunflower oilby a special winterisation technology.The crude wax is refined to Kahlwax 6607L. It is a non chemically treated, saturat-

-Fig. 10 Particle structure of carnauba wax: REM picture of Kahlwax 2442P5(Source: Fraunhofer Institut, Oberhausen)

-Fig. 12 Crude candelilla wax in comparison to the refined types Kahlwax 2039 and2039L

-Fig. 11 Mexican plant euphorbia ceri-fera

Crude

2039

2039 L

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ed, high melting and light coloured wax.By chemistry it is a long chain (aboutC60) wax ester from monovalent alco-

hols and acids mainly. Minor compo-nents like alcohols are not important.The melting point is about 80 C.Sunflower wax forms hard and very ho-mogen thermally stable oil gels and istherefore excellent suitable for light-coloured, practically odourless and taste-less lipbalms, lipsticks and other oil gels.Sunflower wax shows a narrow meltingcurve with no molten contents below55 C. Therefore the oil gels are very wellheat resistant.

Rice bran wax Oryza Sativa CeraBy winterisation of rice oil the crude ricebran wax is obtained.Like sunflower wax the main componentsare long-chain wax esters. The chainlengths of the esters are also around C60.Although it is by chemistry very similarto sunflower wax, applications are quitedifferent.Refined Rice bran wax has a very hy-drophobic character. It forms soft oil gels

and is therefore highly preferred foremulsions like mascaras and skincareproducts. It serves a much less sticky tex-ture than bees wax in W/O-emulsions.

Berry wax from Rhus VernicifluaPeel CeraBerry wax, Kahlwax 6290, is extractedfrom an Asian fruit of the tree rhus ver-niciflua (Fig. 13). The wax consists main-ly of saturated triglycerides.

The specific performance of Kahlwax6290 results from the content of glycerolesters of a C20-C22 dicarboxylic acid.

Berry wax contains:

90% glycerolesters of C16-C18 fattyacids

2-5% glycerolesters of C20-C22

dicarboxylic acids (so-called JaponicAcids)

5% free fatty acids and alcohols.

Kahlwax 6290 is of off-white colour and100% vegetable based. A significant partof berry wax already melts below 30 Cand gives therefore a very silky and softfeeling to the skin like a classical emol-lient. On the other hand berry wax showsvery little to almost no crystallinity lead-ing to very soft but significant textures

in creams (whipped cream like).Kahlwax 6290 is the preferred additivefor skincare emulsions to improve signif-icantly texture and sensory behaviour ofO/W emulsions (Fig. 14).Berry wax is an excellent additive for oilgels to be used in lipsticks (pay-off en-hancer), mascaras and similar productsand is well suited for lipgloss formula-tions as well.The content of relatively high molecularweight glycerol esters from the so calledJaponic Acids makes Kahlwax 6290 tothe preferred ingredient of pencil for-mulations, e.g. lipliner or eyebrow pen-cils. Although soft it improves the breakresistance of pencils.

Excotic waxesFrom the range of exotic natural waxesthe following types from Kahlwax areavailable on demand: myrtle wax (6269),mimosa wax (6602), green tea wax (6640),

jasmin wax (6684), rose wax (6692), lo-tus wax (6694) and orange blossom wax(6699).All these flower and leaf waxes areshowing very special performances butare only of limited availability.

* Authors address:

Dr. Edgar EndleinK.-H. Peleikis

Kahl GmbH & Co. KG

22946 TrittauGermany

Email: [email protected]

-Fig. 14 Improvement of the texture of O/W emulsions with berry wax

-Fig. 13 Fruits and leaves of the Asiantree Rhus verniciflua

sofw journal 4 2011

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