Lathers

Such water, and also that containing salts of multipositive metals, (usually sulphates), is said to be hard since it does not readily produce a lather with soap. Experiments with alkali metal salts can be performed to verify that the hardness is due to the presence of the multipositive metal ions and not to any of the anions present. The hardness due to calcium and magnesium hydrogencarbonates is said to be temporary since it can be removed by boiling ... 

Shake vigorously with a httle sodium hydroxide solution. Determine whether the resulting solution possesses lathering properties. 

Hlkanolamides. The fatty acid alkanolamides are used widely ia shampoo formulations as viscosity and lather builders. They are formed by the condensation of a fatty acid with a primary or secondary alkanolamine. The early amides were compositions of 2 1 alkanolamine to fatty acid. Available technology allows the formation of amides with a 1 1 ratio of these additives. These amides are classified as superamide types. The typical amide used ia shampoo preparations usually contains the mono- or diethanolamine adduct, eg, lauric diethanolamide [120-40-1] (see Amides, fatty acid). 

Soap is one example of a broader class of materials known as surface-active agents, or surfactants (qv). Surfactant molecules contain both a hydrophilic or water-liking portion and a separate hydrophobic or water-repelling portion. The hydrophilic portion of a soap molecule is the carboxylate head group and the hydrophobic portion is the aUphatic chain. This class of materials is simultaneously soluble in both aqueous and organic phases or preferential aggregate at air—water interfaces. It is this special chemical stmcture that leads to the abiUty of surfactants to clean dirt and oil from surfaces and produce lather. 

Because the core of an aqueous micelle is extremely hydrophobic, it has the abiHty to solubiHze oil within it, as weU as to stabilize a dispersion. These solubilization and suspension properties of surfactants are the basis for the cleansing abiHty of soaps and other surfactants. Furthermore, the abiHty of surfactants to stabilize interfacial regions, particularly the air—water interface, is the basis for lathering, foaming, and sudsing. 

In the presence of excess fatty acid, different soap crystalline phase compounds can form, commonly referred to as acid—soaps. Acid—soap crystals are composed of stoichiometric amounts of soap and fatty acid and associate in similar bilayer stmctures as pure soap crystals. There are a number of different documented acid—soap crystals. The existence of crystals of the composition 2 acid—1 soap, 1 acid—1 soap, and 1 acid—2 soap has been reported (13). The presence of the acid—soaps can also have a dramatic impact on the physical and performance properties of the finished soap. The presence of acid—soaps increases the plasticity of the soap during processing and decreases product firmness, potentially to the point of stickiness during processing. Furthermore, the presence of the acid—soap changes the character of the lather, decreasing the bubble size and subsequently increasing lather stabiUty and... 

It would be incomplete for any discussion of soap crystal phase properties to ignore the colloidal aspects of soap and its impact. At room temperature, the soap—water phase diagram suggests that the soap crystals should be surrounded by an isotropic Hquid phase. The colloidal properties are defined by the size, geometry, and interconnectiviness of the soap crystals. Correlations between the coUoid stmcture of the soap bar and the performance of the product are somewhat quaUtative, as there is tittle hard data presented in the literature. However, it might be anticipated that smaller crystals would lead to a softer product. Furthermore, these smaller crystals might also be expected to dissolve more readily, leading to more lather. Translucent and transparent products rely on the formation of extremely small crystals to impart optical clarity. 

Soap Bars. In soap bars the primary surfactant is predominantly sodium salts of fatty acids. These products typically contain between 70 and 85% soap. Occasionally, potassium soap ( 5-30%) is included in the formulation to increase the solubiUty of the soap and, hence, the bar s lathering properties. The low Krafft temperatures for potassium soap are the basis for the lather enhancement, but also limits their content in bars. 

Anionic surfactants are the most commonly used class of surfactant. Anionic surfactants include sulfates such as sodium alkylsulfate and the homologous ethoxylated versions and sulfonates, eg, sodium alkylglycerol ether sulfonate and sodium cocoyl isethionate. Nonionic surfactants are commonly used at low levels ( 1 2%) to reduce soap scum formation of the product, especially in hard water. These nonionic surfactants are usually ethoxylated fatty materials, such as H0CH2CH20(CH2CH20) R. These are commonly based on triglycerides or fatty alcohols. Amphoteric surfactants, such as cocamidopropyl betaine and cocoamphoacetate, are more recent surfactants in the bar soap area and are typically used at low levels (<2%) as secondary surfactants. These materials can have a dramatic impact on both the lathering and mildness of products (26). 

These surfactants, in conjunction with soap, produce bars that may possess superior lathering and rinsing in hard water, greater lather stabiUty, and improved skin effects. Beauty and skin care bars are becoming very complex formulations. A review of the Hterature clearly demonstrates the complexity of these very mild formulations, where it is not uncommon to find a mixture of synthetic surfactants, each of which is specifically added to modify various properties of the product. Eor example, one approach commonly reported is to blend a low level of soap (for product firmness), a mild primary surfactant (such as sodium cocoyl isethionate), a high lathering or lather-boosting cosurfactant, eg, cocamidopropyl betaine or AGS, and potentially an emollient like stearic acid (27). Such benefits come at a cost to the consumer because these materials are considerably more expensive than simple soaps. 

Hardness The scale-forming and lather-inhibiting qualities which water, high in calcium and magnesium ions, possesses. 

The sense of touch allows one to determine if water is hard or soft. For a domestic application in a hard-water area, more soap is required to produce lather than is required in a soft-water area. 

Schaum, m. foam, froth scum lather (Brewing) head. 

Schaum-bestflndigkeit, /. foam-holding capacity. -bier, n. foaming beer, -bildner, m. frothing agent, foamer. -bildtmg. /. formation of foam or froth, -blaae, /. bubble, -brecher, m. foam breaker, froth killer, schaumen, v.i. froth, foam (of wine, etc.) sparkle, fizz (of soap) lather. — v.t. skim, scum. 

To sell well, the shampoo must look good, must feel thick or creamy in the hands, and must produce a nice-feeling lather. It must smell good, and it must not be too expensive. Other selling points might be the currently popular herbal extracts, or amino acids from exotic protein sources such as silk or the milk of pygmy goats. 

Cocamide DEA (or MEA or TEA) is used as a foaming agent, to make lather. The other surfactants generate a certain amount of suds, but this foaming agent is added to get the amount just right. In addition to its foam-stabilizing effects, it is also a viscosity booster—it s thick. 

The first soaps were probably the saps of plants such as Chloro-galum pomeridianum, the roots of which can be crushed in water to form a lather. Other plants, such as soapbark (Quillaja saponaria), soapberry (Sapindus mukorossi), and soapwort (Saponaria officinalis) also contain the same main ingredient, a compound called saponin, which forms the foamy lather. 

Not all bars that lather contain just soap. Many feature the same detergents that you find in shampoo as well. 

Sodium isethionate is an amphoteric detergent used in detergent bar soaps. It makes a dense lather in addition to the lather made by the soap. It is nondrying and mild on the skin. It works equally well in soft or hard water. It is also an antistatic agent in shampoos. 

Since we want the texture of products like shaving cream to stay stable, and since shampoo advertisers like to pretend that unnecessary extra lather is an important selling point, foam stabilizers are helpful in preventing foams from breaking down. 

The use of alkyl ether carboxylates in manual dishwashing agents was described in 1966 [136]. Subsequently several patents mention combinations of alkyl ether carboxylates with aminoxides [137,142], betaines [138,139,142], different anionic surfactants [140], quaternary compounds [141], alkylpolyglucoside [142], and polyhydroxy fatty acid amide [143]. In all cases the ether carboxylates are used to improve mildness and to achieve good cleaning and lathering properties. 

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