Shampoos foaming properties

A.gllsethionates. These are among the oldest of the synthetic detergents and were developed ia Germany to overcome problems of hard water. They are prepared by reaction of fatty acid chlorides with a salt of isethionic acid, ie, 2-hydroxyethanesulfonic acid [107-36-8]. These detergents have moderate foaming properties and have seen only limited use ia shampoos. 

Many of the surfactants made from ethyleneamines contain the imidazoline stmcture or are prepared through an imidazoline intermediate. Various 2-alkyl-imidazolines and their salts prepared mainly from EDA or monoethoxylated EDA are reported to have good foaming properties (292—295). Ethyleneamine-based imida zolines are also important intermediates for surfactants used in shampoos by virtue of their mildness and good foaming characteristics. 2- Alkyl imidazolines made from DETA or monoethoxylated EDA and fatty acids or their methyl esters are the principal commercial intermediates (296—298). They are converted into shampoo surfactants commonly by reaction with one or two moles of sodium chloroacetate to yield amphoteric surfactants (299—301). The ease with which the imidazoline intermediates are hydrolyzed leads to arnidoamine-type stmctures when these derivatives are prepared under aqueous alkaline conditions. However, reaction of the imidazoline under anhydrous conditions with acryflc acid [79-10-7] to make salt-free, amphoteric products, leaves the imidazoline stmcture essentially intact. Certain polyamine derivatives also function as water-in-oil or od-in-water emulsifiers. These include the products of a reaction between DETA, TETA, or TEPA and fatty acids (302) or oxidized hydrocarbon wax (303). The amidoamine made from lauric acid [143-07-7] and DETA mono- and bis(2-ethylhexyl) phosphate is a very effective water-in-od emulsifier (304). 

Sodium alcohol sulfates have a limited solubility compared to sodium alcohol ether sulfates and are more suitable for cream, pearlized, and paste shampoos. Alcohol sulfates are more frequently used in general shampoo formulations in the United States than in Europe. Europe has moved toward alcohol ether sulfates for historical and traditional reasons, different availability of ethylene oxide, and possibly other technical reasons such as the more favorable dermatological properties of alcohol ether sulfates and their better behavior in hard waters. Triethanolamine alcohol sulfates are widely used in shampoos because of their comparatively high solubility in water, good foaming properties, and low irritancy. 

These higher foaming properties are very useful for such cosmetic formulations as shampoos, showerbaths, and so on. This is the same with the forming of fine bubbles and the improving of foam stability of other surfactants such as, for example, alkyl ether sulfates due to the combination with ether carboxylates [57,67-69] (Table 9). 

In combination with alkyl ether sulfates, a synergistic decrease of the irritation level of the ether sulfates and an improvement of the foam stabilization has been described [57,67,78]. A good compromise between mildness and foam properties could be achieved with lauryl ether carboxylic acid sodium salt with 10 mol EO [57,67]. In several articles examples of the use of alkyl ether carboxylates as cosurfactant in mild shampoos as well as bath and shower products have been described [57,69,79]. 

Muller et al. [80] described the use of IOS surfactants together with the sulfonate of a C12-C24 unsaturated fatty acid containing one to six double bonds in shampoo formulations they combine good detergency with good foam properties and mildness to the skin. 

Alcohol sulfates (AS) are usually manufactured by the reaction of a primary alcohol with sulfur trioxide or chlorosulfonic acid followed by neutralization with a base. These are high foam surfactants but they are sensitive to water hardness and higher levels of phosphates are required. This latter requirement has harmed the market for this type of detergent, but they are 2% of production for the major household surfactant market. Sodium lauryl sulfate (R = Cn) is a constituent of shampoos to take advantage of its high-foaming properties. 

By far, the greatest apphcation of fatty alcohol is in the manufacture of fatty alcohol sulfate and fatty alcohol ether sulfate. These materials possess good foaming properties and ready biodegradability and are extensively used as base surfactants for laundry detergent products, shampoos, dishwashing liquids, and cleaners. 

Fatty Amines. Fatty amines are the most important nitrogen derivatives of fatty acids. They are produced by the reaction of fatty acids with ammonia and hydrogen. They are the bases for the manufacture of quaternary ammonium compounds used as fabric softeners and biocides. Fatty amine oxides are mild to the skin with good cleaning and foaming properties and find application as a shampoo ingredient. The above mentioned products are but some of the oleochemical derivatives from coconut fatty acids (5). 

Other coco-based surfactants are sulfosuccinates formed by the reaction of coco fatty alcohol with maleic anhydride and further reaction with sodium sulfite or bisulfite. This product possesses good foaming properties, is compatible with soap, and is a good lime dispersant. It is used in toilet soap formulation, shampoos, hand cleaning pastes, and for scouring raw wool. Its ether variant, with 2-4 moles ethylene oxide, forms intense, finely structured foam and is used in combination with ether sulfate in baby shampoos and bath preparations. 

The foaming potential of shampoos does not directly influence the physical behavior of hair fibers. However, as indicated in the previous section, shampoo foam can infiuence the consumer s perception of hair characteristics. Therefore, a brief introduction into this important shampoo property is provided in this section. 

Uses Thickener in hair conditioners, shampoos, creams/lotions binder in powds., mascara, eyeliner suspending agent thickener for latex paints Features Outstanding tolerance for dissolved electrolytes used pH range of 2-12 does not contribute to foaming Properties Cream to wh. powd., mild odor 98% min. thru 20 mesh sol. in water sp.gr. 1.38-1.40 bulk dens. 400-600 kg/m vise. 300-400 cps (2% aq.) bulking value 0.086 gal/lb pH 6-7 (2% aq.) nonionic 5% moisture by wt. 

Properties Colorless liq. herbal woody minty camphoraceous odor m.w. 154.2 sp.gr. 0.894-0.901 flash pt. 70 C ref. index 1.451-1.457 (20 C) Uses Fragrance in cosmetics, alcoholic lotions, antiperspirants, deodorant sticks, shampoos, foam baths, soaps, detergents, acid cleaners, bleaches, fabric softeners, hard surf, cleaners Use Level 10% max. 

Nonionic surfactants, such as fatty ethoxylated alcohols, are rarely used as primary surfactants in shampoos because of their poor foaming properties (Table 6.8). 

Cocamidopropyl betaine (CAPB) is a common secondary surfactant in shampoo formnlations. It improves mildness and viscosity, and enhances the foam properties. It is milder on the skin than linear alkylbenzene sulfonate (LAS), so adding it to the mix reduces the amount of the harsher detergents needed. It is thicker than the other ingredients, so it can be added to make the mix have the right viscosity. It also has antistatic and moisturizing properties. In many shampoos, CAPB is used in combination with sodium lauryl ether sulfate (LES) (Table 6.10). 

In contrast to the benefits discussed above, cationic surfactants are generally incompatible with anionic surfactants, the primary surfactants used in shampoo formulations, which further limits their applications. The cleaning and foaming properties of cationic surfactants are considerably inferior to those of the anionics, and another major downside is the weighing-down effect on hair. Because of these limitations and compatibility issues, cationic surfactants are not used very often in shampoo formulations, and applications are limited mainly to conditioning, lubricating, and antistatic benefits in conditioners. 

The foaming properties of protein derivatives are also important features for their use in shampoos. They enable formulators to reduce the level of active surfactants in shampoos without reducing overall foaming power. This becomes of great importance in the formulation of low-active, frequent-use type shampoos where overall foaming effects can still be maintained at low-active levels, minimizing skin and eye irritation. 

Af-Fatty P-aminopropionate has an equal number of anionic and cationic groups. A number of iV-fatty P-aminopropionates, under the trade name Deri-phat (Henkel products), has been used in shampoo formulations. Deriphats, as shown structurally in Table 2 [45], either singly or in combination, have shown promise in shampoo formulations. A shampoo with good cleaning and foaming properties has been obtained by combining A-dodecyl-p-alanine and a cationic surfactant (dioctadecyl dimethylammonium chloride). The presence of Deriphats in a shampoo formulation could reduce eye irritation and sting... 

TOMAH Amphoteric N is a unique amphoteric surfactant with exceptionally high foaming properties in the presence of many other surfactants and components typically used in shampoos and personal care products. Amphoteric N is a modified dipropionate amphoteric supplied as a 35% aqueous solution of the partial sodium salt. Amphoteric N is CTFA listed as Sodium C12-15 Alkoxypropyl Iminodipropionate. 

Mild branched chain alkyl ether sulfates for use in shampoo and bath products. These products have excellent wetting and foaming properties. Their mildness is ideal for use in t>aby products. 

Cationic surfactants. Cationic surfactants are known for their anti-microbial efficacy. However, depending on their structure, due to only moderate skin compatibility, and in some cases poor foaming properties, they are rarely used as the main cleaning agent in skin and hair cleansing products. Nevertheless, they are often used in low concentrations in hair conditioners and treatment preparations. They are also used in shampoos, to... 

Applications. Due to their good foaming properties and substantivity on the hair, ester carboxylates are especially suitable in shampoos in combination with alcohol ethoxy sulfates, they reduce skin irritation. 

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