WAX AND THE COSMETIC CHEMIST carnauba wax (chiefly yellow and bleached), candelilla wax, ozokerites (yellow or white), "ceresines," and various synthetic waxes. Reference must be made to the fact that refined ozokerites are nowadays often blends of microcrystalline waxes (and/or petrolatums of the hard or the plastic types) with paraffin waxes. Genuine ozokerites are hardly available even in pre-war days they contained large proportions of paraffin wax. Ceresines are, as a rule, hardened and/or opacified paraffin waxes and of no greater technological value than paraffin wax. Bleached carnauba waxes often contain 75 per cent or more of added paraffin wax. The principal "related materials" concerned are: stearic acid (double and triple pressed), stearyl and cety] alcohols (and sometimes others), "Lanette wax SX" (sulphated lauryl alcohol), "Lanbritol wax N21" (in principle, a non-ionic fatty alcohol-poly- oxyethylene ether of optimum chain-length), "Opal wax," "Castorwax" (hydrogenated castor oil), hydrogenated coconut oil, cottonseed oil, etc., wool wax (i.e., wool fat alcohol) and its esters, monoesters of glycerol (GMS), and of ,various glycols (ethylene, propy- lene, diethylene glycols, etc.), diesters of pentaerythritol, Carbowaxes (polyethylene glycols), polyoxyethylene-fatty acid esters, Spans (sorbitan-f•tty acid partial-esters) Tweens (polyoxyethylene ethers of sorbitan-fatty acid partial-esters), Polawax, Cetomacrogol 1000, Aerosols, andother proprietary brands. Practically all the materials listed above are rn. ore or less waxy in appear- ance some of them are called waxes by their manufacturers. (The ranges of Carbowaxes, Spans and Tweens also include liquid products.) Probably with the exception of Opal wax and the other types of hydro- genated vegetable oils, which primarily serve as stiffening additives, they are used (as such, or appropriately combined, or in conjunction with soaps or alkalis), as emulsifying, wetting or spreading agents. Carbowaxes act chiefly as thickeners and aqueous lubricants. Obviously as these materials are completely lacking wax properties they fall outside the wax definition. On the other hand, they have to be men- 'rioned in a discussion of waxes for various reasons. In the definition of wax, emulsifiability is not listed as an essential requirement. This can be easily understood by referring to the fact that 137

JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS some waxes are emulsifiable, others (particularly the hydrocarbon waxes) are not. A further reason for omitting emulsifiability is that it is not a typical wax characteristic, although wax emulsions are of considerable importance as polishes and for industrial uses (paper coating, textile impreg- nation, etc.). So far as the emulsifiable types of wax are concerned, the ease of emulsi- fication differs greatly. Various waxes often require different emulsifying agents and the resulting emulsions may exhibit a different degree of fluidity, particle size, stability and compatibility with additives. With a few excep- tions, wax emulsions are primarily used where gloss production is aimed at. For the manufacture of cosmetics, the anionic and nonionic emulsifying agents listed under the heading of "related materials" are, as a rule, superior to waxes as a basis for emulsions. On the other hand, the incorporation of a suitable wax often leads to considerable improvements. The Spans, Tweens, and similar non-ionic surface-active agents are marketed in a wide variety of types with different hydrophilic/lipophilic balances, which make it fairly easy to produce either oil-in-water or water-in- oil emulsions. As mentioned above in connection with waxes, the stability of emulsions and their compatibility with medicating additives greatly depends on the emulsifying agent used. Finally, it should be recorded that even hydrocarbon waxes can relatively easily be emulsified with modern emulsifying agents. MODERN CONCEPTS OF WAX ANALYSIS AND EVALUATION The old-established physico-chemical fat-constants remain very useful so long as their limitations are properly understood and the results not simply recorded but correctly interpreted. In the majority of cases they provide circumstantial evidence only, as materials with identical or very similar constants may widely differ in chemical composition and/or technological properties. With the help of the "constants" only clumsy adulterations can be detected and, by the same token, their identifying value is limited and often misleading. For materiMs of a complicated and/or not fully known chemical com- position and for the analytical evaluation of hydrocarbon waxes, the "con- stants" are of very little use, and physical, physico-analytical, and specific performance and keeping tests have proved to be much better tools than those provided by fat-analytical examinations. The determination of the retention number and the retention effect, in conjunction with that of the paste index, paste consistency, and viscosity, permits the evaluation of hydrocarbon waxes, microcrystalline waxes and the like. The same procedure will be found useful also in the case of other waxes. Retention-number and -effect measure the binding and homogenising 138