Lime soap dispersing requirement

This test measures the minimum lime soap dispersant requirement (LSDR) (in g) which keeps 100 g of sodium oleate from precipitating in hard water (333 ppm CaC03). Although this is a convenient laboratory test, it bears little relation to an real in-use situation. 

TABLE 1 Lime Soap Dispersant Requirement (LSDR) of Various Types of Lime Soap-Dispersing Agents (LSDAs)... 

The search for additional LSDAs over the past 10 years has been extensive and the results are both stimulating and rewarding. New formulations, containing a variety of LSDAs, such as amphoteric sulfobetaines, polymers, and even nonionics, have been introduced. Thus, the older theories on the mechanism of lime soap dispersion require modification and supplementation by newer ones. This line of investigation becomes more significant as some of the LSDAs of this report become commercialized [38]. 

Since the amphoterics have far greater lime soap dispersing power than the anionics, an amphoteric LSDA-soap formulation requires less LSD A and tolerates sodium sulfate in the following soap-LSDA formulation [29]. 

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