Anionic surfactants personal care products

Sulfonation and sulfation processes are utilized in the production of wateT-soluble anionic surfactants as principal ingredients in formulated light-duty and heavy-duty detergents, liquid hand cleansers, general household and personal care products, and dental care products. Other commercially significant product applications include emulsifiers, lube additives, sweeteners, pesticides, medicinals. ion-exchange resins, dyes and pigments. 

Applications. Sarcosinates show low irritation potential and are good foamers. Due to these properties they find applications in personal care products where synergistic effects with other surfactants may also be exploited. In combination with other anionics, sarcosinates will often detoxify the formulation and give improved foaming and skin feel. Sarcosinates are also used for their hydrotropic properties - the addition of sarcosinate to other anionics often gives a reduced Kraft point or a raised cloud point if combined with non-ionic surfactants. Lauroyl sarcosinate is used to formulate SLS-free toothpastes which are claimed to have improved taste profile. 

Hydroxysultaines find use in personal care products, where they function as secondary surfactants to enhance the properties of anionic-based formulations, in much the same way as betaines. They are also among the best lime soap dispersants known, so they are used effectively in natural soap based products where they make the use of hard water practical. They are also used in petroleum production chemicals were they serve as foaming agents for acid and foam fracturing procedures. 

The change in charge with pH of amphoteric surfactants affects their properties, such as wetting, detergency, and foaming. Atthe i.e.p., the properties of amphoterics resemble those of nonionics very closely, but below and above the i.e.p. the properties shift towards those of cationic and anionic surfactants, respectively. Zwitterionic surfactants have excellent dermatological properties, and also exhibit low eye irritation consequently, they are frequently used in shampoos and other personal care products (e.g., cosmetics). 

The salts of monoesters of sulphuric acid (mainly known as alkyl sulphates, alcohol sulphates or sulphated higher alcohols and ether sulphates or sulphated ethoxylated alcohols) have been proceeded for tens of years through the competition with alkylbenzenesulphonates and other anionic and nonionic surfactants with respect to the consumer s merits and cost performance. Among other surfactants, the today s world consumption share of alcohol sulphates and ether sulphates is ca. 25 % in household and laundry aids and ca. 20 % in personal care products [81]. The formers are mostly based on sulphates of petrochemical origin whereas the least are more oriented to sulphates from oleochemicals. 

As shown in Figure 22.1, 7% of total surfactants are used in cosmetics and pharmaceuticals, especially in personal care products such as shampoos, bath preparations or toothpastes. Surfactants are important in their function as emulsifiers in creams and lotions. A great variety of anionic, nonionic, cationic and also amphoteric surfactants are used here. 

Different analytes are determined by using electrochemical techniques such as differential pulse voltammetry (e.g., metal ions and chlorhexidine in oral care products, glycolic acid in creams, dyes in lipsticks) or potentiometry (e.g., inorganic compounds and anionic and cationic surfactants in personal care products). Modified carbon electrodes and biosensors have been developed to determine some cosmetic ingredients by techniques such as voltammetry or potentiometry. 

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. 

Surfactants are consumed in various industrial applications directly or indirectly connected to our daily lives. Market shares of surfactants in the United States in 1997 are shown in Figure 1. Consumption of household cleansing products, personal care products, and industrial and institutional (I I) cleansing products exceeds more than 60% of the 5.14 billion pounds of surfactants produced in the United States in 1997 [1]. In Japan, I I consumption exceeds over 50% of total production [2]. Anionic surfactants are the most common type utilized for every application because of their highly effective detergency and relatively lower cost. Thus anionic surfactants dominate household cleaning products. 

STEPAN CO. Personal Care Products Surfactants (Continued) Anionics (Continued) ... 

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. 

Other, even more specialized amide surfactants are known and used in selected products [17]. Sodium cocoyl sarcosinate (CS) and sodium cocoyl tau-rate (CT) are amide-based specialty anionic surfactants closely related to sodium cocoyl isethionate (CIS) structurally (Fig. 13) [18]. All are mild to skin and useful in personal care products. These three surfactants are some-... 

Amphoteric surfactants can function either as anionic or cationic surfactants, depending on the pH of the system. They contain both anionic and cationic functions in the same moiecuie. More costiy to produce than ionic surfactants, amphoteric surfactants represent oniy about 3% of surfactant voiume in Europe and less than 1% in the United States. They are less irritating than other materials and are largely used in personal care products. A distinction can be made between amphoteric and zwitterionic surfactants. This distinction does not affect their analysis. For the analyst, a more important distinction is between am-photerics with a secondary or tertiary amine group and those containing a quaternary amine function. The former only have cationic properties when protonated at low pH, while the quaternary amines have cationic properties even under alkaline conditions. 

In polymer applications derivatives of oils and fats, such as epoxides, polyols and dimerizations products based on unsaturated fatty acids, are used as plastic additives or components for composites or polymers like polyamides and polyurethanes. In the lubricant sector oleochemically-based fatty acid esters have proved to be powerful alternatives to conventional mineral oil products. For home and personal care applications a wide range of products, such as surfactants, emulsifiers, emollients and waxes, based on vegetable oil derivatives has provided extraordinary performance benefits to the end-customer. Selected products, such as the anionic surfactant fatty alcohol sulfate have been investigated thoroughly with regard to their environmental impact compared with petrochemical based products by life-cycle analysis. Other product examples include carbohydrate-based surfactants as well as oleochemical based emulsifiers, waxes and emollients. 

This class of surfactants has possibly the widest range of use of any anionic surfactant. It is found in almost every product where foaming is desirable, in industrial, household and personal care applications. Alkyl ether sulphates are described in terms of their parent alcohol and the degree of ethoxylation. Thus, sodium laureth-2 is the sodium salt of a sulphated (predominantly) C12 alcohol, with an average of 2 mol of ethylene oxide added. Often, the alcohol is assumed to be the typical C12-14 and the surfactant simply called a 2-or 3-mol ether sulphate. 

---