Complex soaps

Within this category, the greases are divided into those based on simple soaps and those based on complex soaps. The latter generally have better high temperature and structural stability properties under high mechanical shear they also have higher resistance to water than their simple soap-based counterparts. 

Calcium complex soap greases, obtained by the reaction of lime and a mixture of fatty acids and acetic acid. These greases offer good high temperature and anti-wear/extreme pressure properties related to the presence, in the soap, of calcium acetate that acts as solid lubricant they have good mechanical stability. 

Lubricating greases frequently contain 10 to 25 % of calcium soaps dispersed in naphthenic or aromatic mineral oils. While greases containing simple soaps are only suitable for use at temperatures up to 60 °C, complex soaps can be used at up to 160 °C [32.50]. 

Aqueous solutions of complex soaps (1-3) are drag reducers, as are certain conventional soaps (4-6) and nonionic surfactants (7-11), and they do not have some of these deficiencies. They have the advantage of regaining their drag reducing effectiveness after subjection to high shear fields. The latter two are effective near their coacervation temperature or cloud point (upper consolute temperature). The addition of electrolyte lowers the cloud point and therefore the temperature at which effective drag reduction occurs. Cloud points can be adjusted to convenient temperatures in this manner. 

White and others (1-3) studied the complex soap, cetyl trimethyl ammonium bromide complexed with 1-naphthol in water. Up to 70% drag reduction was found and shear stress behavior the same as that reported by Savins was observed. This system also proved useful in reducing drag in 20%, (by volume) slurries of sand and of plastic particles in water (2,3). 

White, A., "Flow Characteristics of Complex Soap Systems", Nature, 214, 585-586 (1967). 

Lithium soaps are the most common thickeners used in the formulation of lubricating greases. Lithium soaps used for grease-making are classified into two types Simple soap and complex soap. 

Both soap t5rpes contain the lithium salt of a fatty add. Lithium complex soaps contain an additional lithium salt, or complexing agent, most commonly a dilithium salt of a low molecular weight dibasic organic acid or dibasic ester (13). 

A lubricating grease composition has been described. The composition is based on titanium complex soap thickeners. Several additives are added and described in the Tables 4.5 to 4.9 and shown in Figure 4.4. Zinc di-n-butyldithiocarbamate is shown in Figure 4.5. 

Negative effects on stress-cracking behavior can also be caused by grease thickeners, such as metallic soaps based on lithium, sodium stearate, or lithium-12-hydroxystearate and lithium, barium, or aluminum complex soaps [965]. 

Aside of lubricating properties, corrosion prevention and stability, the dropping point is an important parameter, at which the 1. reaches a certain flow characteristic. The dropping point of Ca-soap 1. is in the range of 100 °C, while high-performance lithium soap 1. of - hydroxy stearic acid reach 190 °C. Complex soaps have also high dropping points. 

The molar ratio between metal and acid determines the nature of the soap. There are neutral soaps (1 1) as well as acid soaps or basic soaps, where either acid or metal is in excess. Complex soaps, e. g., of lea4 may consist of PbO, PbS04 and the m. of Pb. 

Lead soaps are made according to methods 1, 2 a and 2 b if neutral. Method 2 is used for the manufacture of alkaline soaps, and also for making complex soaps. A mixture of PbO and PbS04 is reacted with the fatty acid. - Stearic acid and - oleic acid [1120-46-3] are the main reactants. Three types of stearates are important neutral [1072-35-1], monobasic [90459-52-2] and dibasic [56189-09-4]. Main use is as heat stabilizer and lubricant for PVC (->plastics additives). Other uses are as lubricants in pencil manufacture (- inks) and - paper additives. 

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