Detergents processing

The hydration rate of sodium tripolyphosphate to its stable hexahydrate, Na P O Q 6H20, directly affects detergent processing and product properties. The proportion of STP-I (fast-hydrating form) and STP-II (slow-hydrating form) in commercial sodium tripolyphosphate is controUed by the time—temperature profile during calcination. In most processes, a final product temperature of near 450°C results in a product containing about 30%... 

This reaction is the basis for the Fluff detergent process (26). The heat evolved coupled with the hydration of the STP is sufficient to dry the reaction mass to yield a light density laundry detergent. Requiring a low capital investment, the Fluff process has found use in less-industrialized countries. 

In the detergency process, fatty materials (i.e. dirt, often from human skin) are removed from surfaces, such as cloth fibres, and dispersed in water. It is the surfactants in a detergent which produce this effect. Adsorption of the surfactant both on the fibre (or surface) and on the grease itself increases the contact angle of the latter as illustrated in Figure 4.7. The grease or oil droplet is then easily detached by mechanical action and the surfactant adsorbed around the surface of the droplet stabilises it in solution. 

The commercial availability of enzymes or whole cell biocatalysts for a desired biotransformation is freqnently a limiting factor for commercial application of biocatalysts. Enzymes that are cheaply available are typically used in detergents, processing of food, feed and textiles, as well as in waste management applications. Most of these are hydrolytic enzymes, bnt also isomerases (e.g. glucose isomerase) and oxidorednctases are used on indnstrial scale (Table 5.1). 

Time - resolved spectra of a solid hydrocarbon layer on the surface of an internal reflection element, interacting with an aqueous solution of a nonionic surfactant, can be used to monitor the detergency process. Changes in the intensity and frequency of the CH2 stretching bands, and the appearance of defect bands due to gauche conformers indicate penetration of surfactant into the hydrocaibon layer. Perturbation of the hydrocarbon crystal structure, followed by displacement of solid hydrocaibon from the IRE surface, are important aspects of solid soil removal. Surfactant bath temperature influences detergency through its effects on both the phase behavior of the surfactant solution and its penetration rate into the hydrocaibon layer. 

Solid soils are commonly encountered in hard surface cleaning and continue to become more important in home laundry conditions as wash temperatures decrease. The detergency process is complicated in the case of solid oily soils by the nature of the interfacial interactions of the surfactant solution and the solid soil. An initial soil softening or "liquefaction", due to penetration of surfactant and water molecules was proposed, based on gravimetric data (4). In our initial reports of the application of FT-IR to the study of solid soil detergency, we also found evidence of rapid surfactant penetration, which was correlated with successful detergency (5). In this chapter, we examine the detergency performance of several nonionic surfactants as a function of temperature and type of hydrocarbon "model soil". Performance characteristics are related to the interfacial phase behavior of the ternary surfactant -hydrocarbon - water system. 

An examination of the time - resolved spectra can be made, which provides additional details about the temperature - dependent changes in the nature of the hydrocarbon - bath interface during the detergency process. 

Sodium tripolyphosphate (STP) was commercially available in the mid-1940s and had replaced TSPP because of its superior detergent processing, solubility, and hardness ion-sequestering characteristics. Sequestration is defined as the reaction of a cation with an anion to form a soluble complex. The sequestration of Ca and Mg " ions leads to softened water and is the most important function of any detergent builder [3, 4]. 

Although the contacting experiments were performed with surfactant systems typical of those used in enhanced oil recovery, application of the results to detergency processes may be possible. For example, the growth of oil-rich intermediate phases is sometimes a means for removing oily soils from fabrics. Diffusion path theory predicts that oil is consumed fastest in the oil-soluble end of the three-phase regime where an oil-rich intermediate microemulsion phase forms. 

Use Organic intermediate, cross-linking of rigid polyurethane foams, chelating agent, humectant, gas absorbent, resin formation, detergent processing. 

Flow induced phase inversion (FIPI) has been observed by the author and applied to intensive materials structuring such as agglomeration, microencapsulation, detergent processing, emulsification, and latex production from polymer melt emulsifica-A diagrammatic illustration of FIPI is shown in Fig. 4. When material A is mixed with material B, in the absence of any significant deformation, the type of dispersion obtained [(A-in-B) or (B-in-A)] is dictated by the thermodynamic state variables (TSVs) (concentration, viscosity of components, surface activity, temperature, and pressure). If the... 

The primary function of builders in the detergency process is to tie up the hardness ions, Ca2+ and Mg2+, which are naturally found in water. They also provide other valuable benefits including maintaining the alkalinity of the wash solution, functioning as antiredeposition and soil dispersing agents and, in some cases, as corrosion inhibitors [80-84],... 

Liquid detergent process patents frequently define both compositional and process requirements, such as raw material concentrations and specifications, order of addition of critical components, thermal history, premix or adjuvant preparation methods, product/process stabilizers, distributive and dispersive mixing requirements, and process instrumentation. These patents apply to the production of primary raw material constituents, such as surfactants, builders, conditioning agents, rheology regulators, hydrotropes, disinfectants, bleach additives, etc., in addition to the specification of fully formulated detergent systems. 

As more restrictions on product preservatives have been set in the last 10 years, more instances of microbial contamination have appeared and liquid detergent process equipment and operations have approached those used in the food and pharmaceutical industries. Process equipment is being installed to a more sanitary level, which means easier to clean and disinfect. Predominantly the equipment is designed for cleaning in place (CIP) without the need to disassemble. This chiefly means that surfaces are polished, circulation dead spaces are avoided, and drainage is virtually perfect. Usually the equipment is washed with alkaline and acid solutions, and then with a disinfectant solution. Additional equipment to handle and recirculate disinfectant solutions becomes part of the system design. 

Studies of diffusional phenomena have direct relevance to detergency processes. Experiments are reported which investigate the effects of changes in temperature on the dynamic phenomena, which occur when aqueous solutions of pure non-ionic surfactants contact hydrocarbons such as tetradecane and hexadecane. These oils can be considered to be models of non-polar soils such as lubricating oils. The dynamic contacting phenomena, at least immediately after contact, are representative of those which occur when a cleaner solution contacts an oily soil on a polymer surface. With Ci2E5 as non-ionic surfactant at a concentration of 1 wt.% in water, quite different phenomena were observed below, above, and well above the cloud point when tetradecane or hexadecane was carefully layered on top of the aqueous solution. Below the cloud point temperature of 31°C very slow solubilisation of oil into the one-phase micellar solution occurred. At 35°C, which is just... 

A. Nuria, The role of Microemulsions in Detergency Process, in Industrial Applications of Microemulsions , C. Solans and H. Kunieda (Eds.), Surf. Science Ser., Vol. 66, Marcel Dekker, 1997, pp. 377. 

For practical purposes, in the detergency process, the use of microemulsions should be considered only for special problems such as for the pretreatment of heavily oil soiled workwear. In these processes especially the reusability in the cleaning process is an essential advantage of microemulsions as cleaning media. 

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