Esterquats properties

Taking into consideration its physico-chemical properties, removal efficiencies, low biodegradability, predicted environmental levels, toxicity, and the need to provide sufficient safety margins for aquatic organisms, the demand for alternative cationic surfactants arose. Since 1991, DTDMAC has been replaced in some European countries due to producer s voluntary initiatives with new quaternary ammonium compounds, the esterquats. These contain an ester function in the hydrophobic chain (Table 1.3) that can be easily cleaved, releasing intermediates that are susceptible to ultimate degradation [24-26]. The effects of the phasing-out and replacement of DTDMAC can be demonstrated by the results of a Swiss study, where the surfactant... 

In esterquat-based and more so in DHTDMAC-based softening compositions, PDMS improves the wettability of the treated cotton at low PDMS/quaternary ratio. This property is surprising, considering the strong hydrophobicity of the material. Since PDMS is not very substantive, it is easily removed in the subsequent wash. 

TABLE 2 Compilation of Acute and Chronic Toxicity Data of Esterquats and Their Degradation Products to Aquatic Organisms [14,37,38] Physical Properties of Some Alkanolamines... 

The fatty acids used to manufacture esterquats for fabric softeners usually have a high Cig and Cig content. The used fatty acids are tallow or palm based. The alkyl groups are partially or fully hardened. Softening performance and physical properties like dispersion viscosity and melting point depend on chain length and the degree of unsaturation of the alkyl chains in the esterquat [50]. Dispersion stability is an important item, especially in the United States for the ultraconcentrated formulations. 

Softener esterquats based on alkanolamines have been extensively investigated for their environmental properties. A number of very comprehensive studies has been published [14,37,41]. All materials biodegrade rapidly and show comparatively low toxicity to aquatic organisms. It has been suggested that abiotic degradation (hydrolysis of esterbonds) contributes to the favorable environmental profiles of these esterquats [37],... 

Triethanolamine based esterquats are a mixture of mono- di- and tries-terquats. It is claimed that for softeners and hair conditioners an esterquat with at least 50% diester content is preferred [49]. Methyldiethanolamine-based esterquats are mainly diesterquats with only slight amounts of mono-esterquat. Monoesterquats are useful as cationic surfactants in hair care formulations [124]. Solid esterquats with improved dispersibility and emulsifying properties are obtained by quaternization of fatty acid triethanolamine esters in the presence of a dispersing agent or nonionic emulsifier [125-127]. Esterquats can be used in sprayable conditioning systems for hair care [128]. 

Like other quaternaries, esterquats exhibit fabric softening properties. They are also claimed to be nonsensitizing agents in the dermatological sense and are readily biodegradable. 

Applications. The esterquats are suitable substitutes for straight quaternaries they present an improved environmental profile and comparable softening properties compared to straight quaternaries. Indeed, the esterquat molecules show faster biodegradability compared to the ditallow-dimethyl-ammonium compound (DTDMAC) which has been the... 

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