Nonionic surfactants
The main varieties of nonionic surfactants are alkyl alcohol amides (FFA), fatty alcohol ethoxylates (AE), alkyl phenol ethoxylates (APE or OP). Nonionic surfactants have good solubilization, washing, antistatic, irritation, calcium soap dispersion and other properties; the actual application of pH range is wider than the general ionic surfactants; in addition to decontamination and foaming, other properties are often better than the general anionic surfactants. Experiments show that: adding a small amount of nonionic surfactants in ionic surfactants can make the surface activity of the system increase – the same active substance content comparison.
Alkyl alcohol amides are a class of nonionic surfactants with superior performance and wide range of applications and high frequency of use, and are commonly used in various liquid detergents. The specifications of alkyl alcohol amides commonly used in liquid detergents are “2:1 amide” and “1.5:1 amide,” and “1:1 amide” can also be used. These three specifications differ in terms of water solubility and thickening properties. Generally speaking, “1.5:1 amide” is more moderate and is more often used in detergents. Usually “1:1 amide” is used in combination with other water-soluble surfactants for easy solubilization. Alkanolamides are more suitable for alkaline detergents, but can also be used in general acidic detergents. Alkyl alcohol amides are the cheapest of the nonionic surfactants, with a price of RMB 7800/t in 2002.Alkyl alcohol amides are more frequently used in liquid detergents than fatty alcohol polyoxyethylene alcohols. The nonionic surfactants used in shampoo are often alkyl alcohol amides. The reason may be: the comprehensive function of FFA is better or more than AE; the price of FFA products is lower than AE; the solubility of FFA is better than AE; the foaming property of FFA is better than AE.
4. Amphoteric surfactant
Amphoteric surfactant refers to the surfactant with both anionic and cationic hydrophilic group, so this surfactant is cationic in acidic solution, anionic in alkaline solution, and has similar nonionic property in neutral solution. Amphoteric surfactants are easily soluble in water, soluble in concentrated acid and alkali solutions, even in the concentrated solution of inorganic salts can also be dissolved, good hard water resistance, skin irritation is small, fabric softness is good, good antistatic properties, good bactericidal effect, and a variety of surfactants with good compatibility.
These products can be used in a wide pH range, but from the viewpoint of the ionic state corresponding to different acid and alkaline media conditions, the performance under acidic and neutral conditions should be better than under alkaline conditions. Generally speaking, the price of amphoteric surfactants is higher than that of nonionic surfactants.
Important amphoteric surfactants include dodecyldimethyl betaine and carboxylate imidazolines. Compared with anionic surfactants, nonionic surfactants have more comprehensive performance and fewer defects–only the detergency and foaming are poorer; compared with nonionic surfactants, some of the performance of amphoteric surfactants is better, and the rest of the performance is not lagging behind. Amphoteric surfactants have better foaming ability than general nonionic surfactants—the foaming ability of AE is poor; better bactericidal ability—relative to nonionic and anionic. Better conditioning. Therefore, in liquid detergents, amphoteric surfactants are mainly used in shampoo shampoos, followed by skin cleansers such as shower solutions.
