Anionic Surfactant Sulfates
Commonly found in this class of active agents are fatty alcohol polyoxyethylene ether sulfate
sodium sulfate and sodium dodecyl sulfate. Sodium fatty alcohol ethoxylate sulfate is also known as AES, sodium alcohol ether sulfate. It is easily soluble in water, with a yellowish viscous liquid (semi-transparent) appearance when the content of active substance is 70%, and its stability is inferior to that of general sulfonates. It is hydrolyzed quickly at pH4 or below, but its hydrolysis stability is good under alkaline environment. Under the condition of 30℃3days,pH2,pH4,pH10,the hydrolysis rate is 100%,50% and 0.Irritation is small,the irritation index of 10% solution is 2.3.Biodegradation rate is more than 90%.LD50 is 1800mg/kg.
Sodium dodecyl sulfate is also known as AS, K12, sodium cocosulfate, sodium lauryl sulfate, foaming agent. It is soluble in water, the solubility is about 15 in 25℃ water, but the degree of water solubility is inferior to AES. it is not sensitive to alkali and hard water, but the stability is inferior to general sulfonate under acidic condition, close to AES, long-term heating should not exceed 95℃, the irritation is medium in the surfactant layer, the irritation index of 10% solution is 3.3, which is higher than AES and lower than LAS. the LD50 is 1,300mg/kg. LD50 is 1300mg/kg.
AES can be used in shampoo, shower liquid, liquid detergent for tableware (dishwashing liquid) and liquid detergent for clothes. If the pH value quality index allows, the pH value should be adjusted to be as high as possible, such as neutral or alkaline. When AES must be used under the condition of lower pH value (in shampoo), its ethanolamine salt is generally used. the water solubility of AES is better than that of AS; it can be formulated into transparent aqueous solution in any proportion at room temperature. not only is AES more widely used than LAS in liquid detergents, but also it is better compatible; it can be compounded with a lot of surfactants in binary or multicomponent to form transparent aqueous solution. AES in the synthetic surfactants, the output of the third, the price is lower than AS, in 2002 70% AES price of 8500 yuan / t. AES outstanding advantages are less irritation, good water solubility, good compatibility, in the prevention of skin dryness and roughness of the performance of the good; the disadvantage is that the stability of the acidic medium is slightly poor – – must control the pH far from the water, and must be used in a large amount of water. The disadvantage is that the stability in acidic medium is a little bit poor – must control the pH far more than 4, the decontamination power is inferior to LAS, AS.
AS in liquid detergents, pay attention to the pH medium conditions – acidity is not too high; in shampoo shampoo application must be the use of its ethanolamine salt or ammonium salt; in the shower liquid is often the use of its ethanolamine salt or ammonium salt. The use of its
ethanolamine salt can not only increase the stability of acid resistance, but also help to reduce the irritation. 10% triethanolamine salt irritation index of 3.0. AS in the dishwasher liquid detergent application frequency is small, and seldom as the main surfactant that is, the amount of formulation is small, the main reason is to reduce the cost of the product is unfavorable, and second is that these products on the foaming property almost no requirements. AS in synthetic surfactants, the production is the fifth, the price is higher, in 2002, the price of powder for 15000 yuan / t. AS in addition to good foaming and decontamination power, other aspects of the use of performance are not as good as AES. such as acid stability is a little worse, the irritation is relatively large – just less than the LAS, the price is also the highest in the common anionic surfactants. In common anionic surfactants, the price is also very high.
