Builders, detergent carbonates

FIG. 8.13 Sequestration of water hardness ions by detergent builders. Sodium polyacrylate Mw = 170,000, STPP (sodium tripolyphosphate), NTA (nitrilotriacetic acid), EDTA (ethylenediamine tetraacetic acid), sodium citrate, CMOS (sodium carboxymethoxysucci-nate), sodium carbonate, zeolite A. (Reproduced from Nagarajan, M.K., J. Am. Oil Chem. Soc., 62, 949, 1985. With permission.)... 

Ammonium carbonate Citric acid Methyl vinyl ether/maleic acid copolymer Nitrilotriacetic acid Oxidized cellulose PEG-2 cocomonium chloride Sodium disilicate Sodium metaphosphate Sodium sesquicarbonate Sodium silicoaluminate Tetrapotassium pyrophosphate Tetrasodium EDTA Zeolite Zeolite synthetic detergent builder, household cleaners Potassium silicate detergent builder, laundry powders Sodium sulfate... 

Production of Detergent Builders Phosphates, Carbonates, and Polycarboxylates... 

Polycarboxylates, also known as polyacrylates, are polymers having a carbon-carbon backbone with attached carboxyl groups. In household consumer products, the anionic polycarboxylates most commonly used are copolymers of acrylic acid and maleic anhydride, copolymers of acrylic acid and methacrylic acid, or polymers of acrylic acid. Polycarboxylates find use as detergent builders and as partial replacements for polyphosphates. However, they are very expensive for use in high concentrations as builders in detergent formulations and also have poor biodegradability [16]. 

The efforts of the detergent industry toward solution of its part of the eutrophication problem are, at this point, less complete than its response to the biodegradabihty problem. Soda ash, Na2C02, sodium siUcate, and, to a lesser extent, sodium citrate formed the basis of the early formulations marketed in the areas where phosphates were harmed. Technically, these substances are considerably less effective than sodium tripolyphosphate. As a precipitant builder, soda ash can lead to undesirable deposits of calcium carbonate on textiles and on washing machines. 

FIG. 19 Detergency performance of LAS/AES/AS mixtures with phosphate and carbonate builders. Shaded zones represent optimum detergency performance. Conditions 38°C, 0.15 concentration, 15% surfactant/30% builder, 50 and 150 ppm hardness, sebum soil. (From Ref. 42.)... 

Nonionic surfactants, as mentioned previously, have been widely adopted due to their characteristics and properties and, in particular, because they do not require the presence of undesirable phosphate or caustic builders in detergent formulation. However, the relatively lesser degree of biodegradability is an important disadvantage of the nonionic surfactants compared to the ionic ones. Adsorption on activated carbon and various types of clay particles is, therefore, one of the processes that has been effective in removing heterodisperse nonionic... 

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