Hand creams

Why does hand cream lose its milky appearance during hand rubbing ... 

Most hand creams are colloidal, and generally have a thick, creamy consistency. The majority of hand creams are formulated as a liquid-in-liquid colloid (an emulsion), in which the dispersion medium is water based, and the dispersed phase is an oil such as palm oil or cocoa butter . These oils are needed to replenish in the skin those natural oils lost through excessive heat and work. 

The hand cream is opaque as a consequence of the Tyndall effect. 

The mechanical work of rubbing and kneading the hand cream breaks the colloid. The oil enters the skin - as desired - while the water remains on the skin surface before evaporating (hence the cooling effect mentioned above). 

Most oil-in-water emulsions (like cream or hand cream) feel creamy to the touch, and most water-in-oil emulsions (like margarine) feel greasy. 

Handbook of Surfactants (Porter), 24 144 Hand creams, surfactants in, 24 158-159 Hand-dishwashing liquids, acute oral LD50 ranges, S 446t... 

The lanolin extracted from the wool is purified further for use in cosmetics, hand cream, boot-polish, and so on. Part of the permeate from the ultrafiltration is recycled to save fresh water. A particular advantage arises from the fact that the dissolved sweat components exhibit... 

A-Nitrosodiethanolamine at levels of 600-7386 ppb was detected in 11 samples of cosmetics in the United States which included hand creams, face creams, shampoos, cocoa butter cream, moisturizing lotion and a make-up remover (all products listed diethanolamine and/or triethanolamine as ingredients) (Tunick etal., 1982). TV-Nitroso-diethanolamine was found in all seven cosmetic formulations one with traces (< 10 ng/g) and six at levels of 41 7 000 ng/g and in 12 of 13 lotions (seven with traces <10 ng/g and five with 14-140 ng/g) and in eight of nine hair shampoos (three with traces < 10 ng/g and live with 17-280 ng/g) in the United States (Fan et al., 1977b). Of 191 cosmetics analysed, 77 contained from 10 to more than 2000 ppb N-nitrosodiethanolamine (Elder, 1980). Westin etal. (1990) analysed 20 different suntan lotions in Israel and found that three were contaminated with 17-27 ppb TV-nitroso-diethanolamine (with traces 5-10 ppb). 

PG, THBP, TBHQ, NDGA, BHA, Ionox 100, OG, BHT, DG Butter, lard, margarine, shortening, hand creams extraction into acetonitrile after mixing with hexane Supelcosil LC-18 5 /urn, 150 X 4.6-mm ID A Water that contained 25 mM sodium acetate and 25 mM citric acid-methanol 95 5 (v/v) B Water that contained 25 mM sodium acetate and 25 mM citric acid-methanol-acetonitrile 20 40 40. Gradient Initial 25% B with linear increase to 100% B over 12 min, hold for 8 min, return to 25% B and hold 10 min Electrochemical, UV 280 nm 128... 

Rattner, H. Use of urea in hand cream, Arch. Dermatol. Siph., 48, 47, 1943. 

Hand creams are formulated to carry out a variety of cosmetic functions. Among these are softening the skin and preventing dryness elimination of natural waste products (oils) by emulsification cooling the skin by radiation thus helping to maintain body temperature. 

In addition, hand creams must have certain ingredients that aid spreadibility and provide body. In many cases added fragrance improves the odor, and in some special cases medications combat assorted ills. 

Besides the above five basic ingredients, some hand creams also contain alcohols such as propylene glycol (1,2-propanediol), and esters such as methyl stearate, to provide the desired texture of the hand cream. 

In this experiment you will prepare four hand creams using the combination of ingredients as shown in Table 40.1. 

Test the pH of the hand creams prepared using a wide-range pH paper. 

Rubbing a small amount of the hand cream between your fingers, test for smoothness and homogeneity. Also note the appearance. Record your observations on the Report Sheet. 

Dispose of your hand cream preparations in the waste containers provided. DO NOT place in sink. 

What is the most abundant component of all hand creams ... 

In comparing the properties of the hand creams you produced, ascertain the function of each of the missing ingredients in the hand cream ... 

A hand cream appears smooth and uniform after you prepared it, but in a week of storage most of the water settles on the bottom and most of the oil separates on the top. What do you think may have gone wrong with the hand cream preparation ... 

Was the pH of all your hand cream preparation the same If not, explain the differences. 

In one of your hand cream formulation there was no mineral oil. What characteristics was observed in the absence of mineral oil Explain. 

Is used as a component in hand creams and other cosmetic formulations. This versatile ester is also a component for industrial lubricants and lubricant softeners for textiles. 

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