The main categories of adjuvants are: fillers, anti-redeposition agents, optical brighteners, thickeners, enzymes, solubilizers, etc.
①Filling agent: There are anhydrous sodium sulfate (Na2SO4, commonly known as Yuanmingfen) and sodium sulfate (Na2SO4·10H2O, commonly known as Glauber's salt) containing 10 crystal waters. Sodium sulfate has a wide range of sources and is cheap. It is mainly used as a filler in washing powder, and it also helps to dry and shape and prevent product agglomeration.
②Anti-redeposition agent: The anti-redeposition agent widely used in synthetic detergents is carboxymethyl cellulose (CMC). Synthetic detergents can remove adhering soils from fabrics, but the sloughed soils will re-attach to the fiber surfaces of the fabrics, a phenomenon known as soil "redeposition". Carboxymethyl cellulose has the effect of preventing this phenomenon. Its dosage in washing powder is generally 1 to 3%. In recent years, polyvinylpyrrolidone has been used, which has good anti-redeposition effect on various fibers, and has the advantages of high solubility and good compatibility with inorganic salts.
③ Optical brightener: an indispensable component of synthetic detergents. In order to increase the whiteness, a small amount of blue (also called blue whitening) can be added as a blue dye for the complementary color of the yellowish tone, thereby improving the apparent whiteness of visual observation. Optical brighteners increase whiteness by converting ultraviolet light into visible light. The whiteness of the luminous light actually reflected in the vision is the effect of the optical brightener. Optical brighteners for detergents include diamine stilbene disulfonic acid type (for cotton fabrics) and naphthalene triazole stilbene type (for cotton and synthetic fibers).
④Thickener: a substance that can increase the consistency of the solution. CMC is a relatively inexpensive common thickener. Some inorganic thickeners such as colloidal silicon dioxide are commonly used for pastes; organic thickeners are used for clear and transparent solutions, such as Carbopol series products and modified cellulose (such as hydroxypropyl methyl cellulose). cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, etc.). These modified celluloses are soluble in cold water, but insoluble in hot water and most organic solvents. Both inorganic salts and pH value will affect the properties of the above thickeners, so before determining the use of a thickener, it is necessary to conduct a sufficient storage test after trial-producing the product according to the formula.
⑤Enzyme preparation: The enzymes added in detergents are mainly proteolytic enzymes and lipolytic enzymes. The former can decompose protein dirt in blood, meat and eggs; the latter can decompose fat, and cellulase can also be added. Detergent enzymes not only require stability in alkaline medium and high temperature resistance, but also have good compatibility with other components of detergents.
⑥Solubilizer: When formulating liquid detergent, it is usually necessary to add a solubilizer to keep all the components in the formula in a dissolved state. A solubilizer is a compound containing a hydrophilic group and a lipophilic group in the molecule, and has the property of dissolving other organic substances in water or an aqueous salt solution at a high concentration. Its molecular morphology is similar to that of surfactants, but the lipophilic group is a low-molecular-weight hydrocarbon. Such as lower alkyl benzene sulfonates, they are particularly effective in liquid detergents formulated with anionic actives. A series of compounds as solubilizers have increasing solubilities in the order of sulfonates of benzene, toluene, xylene and cumene.
Solubilizers are used in the production of washing powders, in addition to formulating liquid detergents. Before spray drying, adding a solubilizer to the slurry can reduce the viscosity of the slurry, that is, the amount of water used in the preparation of the slurry can be reduced, thereby improving the production capacity of the dusting tower. In addition, solubilizers such as sodium toluenesulfonate can also increase the fluidity of the finished powder and prevent agglomeration, especially when the washing powder with a high content of sodium linear alkyl benzenesulfonate, adding a solubilizer is particularly necessary.
In addition, organic adjuvants with less dosage include alkanolamides, amine oxides, pigments, flavors, etc. Alkanolamide itself is a non-ionic surfactant with good degreasing ability and hard water resistance. Alkanolamides are often used as foam stabilizers in synthetic detergents. The amount added is about 2 to 3%. In addition, it can improve the decontamination effect, anti-precipitation, reduce the irritation of sodium alkyl benzene sulfonate to the skin, prevent the skin from drying out, improve the hand of the fabric and inhibit the metal rust. Amine oxide is also a kind of non-ionic surfactant, in addition to having the characteristics of alkanolamide, it also has antistatic effect, and it is also the currently used foam stabilizer. Certain pigments are added to synthetic laundry detergents to make colored powders that improve the appearance of the product. Fragrances are added to detergents to improve the smell of products.
