Surfactant compatibility with skin, mildness

There has been a recent revival of interest in zwitterionic surfactants (L 4) because of certain useful properties shown by these molecules, including 1) mild behavior on the skin, 2) compatability with both anionics and cationics, 3) adsorption onto skin and hair, and 4) lime soap dispersing ability. Although this type of surfactant has been produced and used industrially for the last few decades, there have been few studies of the properties of well purified surfactants of this type (5-11) and almost all of these have been concerned with the micellar properties of these compounds rather than with their behavior at interfaces. 

U.S. 5514369 (1996) Salka etal. (Henkel) Alkyl poly glycosides, betain, and polymeric slip agents Mild to skin and eyes more efficient deposition of antidandruff agents anionic surfactant free compatible with cationic materials such as conditioners and colorants... 

In recent years, protein-based surfactants are finding some applications in personal care products due to their abilities to interact with skin and hair." A-acyl polypeptide condensates (protein derivatives) belong to the mild surfactant category with foaming performance inferior to alkyl sulfates, but they produce creamy lather and leave hair feeling soft and manageable. However, it appears that extra attention and care should be taken to ensure preservation of these protein derivatives due to compatibility with other anionic surfactants when present in shampoo formulations. 

These surfactants are well established as extremely mild surfactants [7]. They are referenced in the CTFA dictionary as sodium coco (or lauryl) amphoacetate and disodium coco (or lauryl) amphodi-acetate. Amphoterics are widely used in mild, tear-free shampoos and sensitive skin cleansers due to their favorable surfactant properties, low irritation profile, and irritation-mollifying properties [8], Amphoacetates or diacetates are excellent foaming agents, even in hard water, and they exhibit compatibility with all other types of surfactants. 

Acylated protein hydrolysates are known to be very mild surfactants. In the formulation of surfactants, the addition of small amounts of acylated protein hydrolysates to the more strongly irritating bulk surfactants results in a more than proportional improvement in their compatibility with the skin [10]. 

Mild to the skin. Foam builder, thickener and emollient. Excellent foam stability in hard water, acidic and alkaline solutions. Compatible with nonionic, anionic and most cationic surfactants. 

Their functional properties are similar to those of betaines. They are mild for skin but generally show a poor to moderate emulsifying ability. They are compatible with other surfactants (formation of complexes with anionics) and tolerate hard water and a high level of electrolytes. 

Sarcosinates Performance similar to soaps but milder and not alkaline compatible with cationic surfactants Used to improve mildness, reduce skin drying... 

Uses Wetting agent, detergent for industrial cleaners including wax strippers, bottle washes, acid and alkaline metal cleaners, carpet cleaners Features Lower foam mild to skin compat. with other surfactants high caustic tolerance... 

Uses Surfactant for mild shampoos, skin cleansers, liq. hand soaps, body washes, toweletles, automobile washes, heavy duty cleaners, dishwashing preps. Features High toam mild to eyes and skin compat. with other surfactants high elecbelyte tolerance... 

Uses Cleanser, vise, modifier and solubilizer, emollient tor baby shampoos, baby washes, sensitive skin formulations and other mild personal care formulations emulsifier and solubilizer for fragrances and oils Features Mild compat. with other nonionic surfactants and most anionic and cationic surfactants... 

Uses Surfactant for mild hand soaps, incontinence washes, bath gels, bubble baths, conditioning shampoos, facial washes anti-irritant for anionics Features Mild compat. with lauryl sulfetes, lauryl ether sulfates, alpha olefin sulfonates, amides, and betaines imparts a smooth feel to skin after drying provides detergency to formulations without irritation Properties Amber cl. liq. pH 5.5-7.5 (10% aq.)... 

Uses 0/w SE wax for neutral, mildly acidic and alkaline systems incl. relaxers, creams/lotions, hair and skin care, creme rinses, antiperspirants Features Compat. with anionic, nonionic, and cationic surfactants mod. electrolyte tolerance... 

Features Mild high foaming good skin compatibility can be applied in a pH range of 5-9 compat. with anionic, amphoteric and nonionic surfactants... 

Uses Emulsifier, lubricant, slip aid, surfactant, antitackifler, emulsion stabilizer, emollient, spreading agent for hair and skin prods, including creams, body lotions, after-shave balms and gels, shampoos, and conditioners Features Nongreasy compat. with many anionic surfactants and quaternary compounds normally used in hair care formulations Properties Gardner 2 cl. yel. liq. mild odor sol. in ethanol disp. in water, propylene glycol, isopropyl myristate and min. oil acid no. 11 100% act. 

Uses Surfactant, conditioner, and emulsifier, and detergent for skin and hair prods. Features Good on treated hair compat. with other surfactants and does not adversely effect foam or detergency in shampoos Properties Gardner 6 max. yel. liq. mild odor water-disp. dens. 0.99 g/ml b.p. 

Chem. Descrip. Undecylenamidopropyl betaine Ionic Nature Amphoteric CAS 133798-12-6 EINECS/ELINCS 308-783-3 Uses Antidandruff base, fungicide for antidandruff shampoos mild surfactant Features Offers lathering and washing chars. well-tolerated by skin active at low cones. compat. with anionic and cationic surfactants AMPHOSOL CB3 [Stepan]... 

Uses Mild conditioner, surfactanf emollient, emulsifier for shampoos, bath gels, conditioners, shave prods., skin creams and lotions Features Broad pH stability salt-tolerant compat. with all dasses of surfactants Properties Amber liq., mild ar. odor sp.gr. 1.06 HLB 9.0 pH 7 25% solids, 30% act. 

Betaines are insensitive to water hardness, almost nontoxic, mild to the skin and have antimicrobial properties. They are therefore used in cosmetic formulations and in household cleaners. They are compatible with other surfactants and have good washing and foaming performance. 

The solubihty characteristics of sodium acyl isethionates allow them to be used in synthetic detergent (syndet) bars. Complex blends of an isethionate and various soaps, free fatty acids, and small amounts of other surfactants reportedly are essentially nonirritant skin cleansers (66). As a rule, the more detersive surfactants, for example alkyl sulfates, a-olefin sulfonates, and alkylaryl sulfonates, are used in limited amounts in skin cleansers. Most skin cleansers are compounded to leave an emollient residue on the skin after rinsing with water. Free fatty acids, alkyl betaines, and some compatible cationic or quaternary compounds have been found to be especially useful. A mildly acidic environment on the skin helps control the growth of resident microbial species. Detergent-based skin cleansers can be formulated with abrasives to remove scaly or hard-to-remove materials from the skin. 

Good synergy with anionic surfactants Excellent environmental compatibility Improve rheological properties and sebum solubilization Good foaming properties Very mild on skin... 

For 40-50 years, phosphate esters occnpied the role of relatively small-volume anionic surfactants. They have been unable to effectively compete economically and possessed lesser surface activity than sulfates. Consequently, they have primarily been nsed in indnstrial, household, industrial, and institutional (HI I), and agricultural applications. The recent advance in processes for high MAPs and the development of phospholipid-type molecnles have provided prodncts with increased surface activity, mildness, and superior skin compatibility. Conseqnently, interest is beginning to develop in the personal care indnstry. 

Amphoterics are usually used in conjunction with other surfactants (anionics or nonionics) to boost desired properties such as foam or detergency. Since the optimal surface activity of amphoterics takes place around neutral pH, they are particularly appreciated in personal care products (shower gels, foam baths, shampoos, etc.) for their mildness and skin compatibility. 

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